Off-grid toilets. Manual for safe sanitation in informal settlements by AECID PUBLICACIONES

This book is dedicated to everyone living under challenging conditions in informal settlements worldwide, and particularly to the people in Karail, Dhaka. The lack of safe sanitation is just one of the many shortages they face daily and is a clear manifestation of rampant inequality across the world.

Contents

Aerosan

Banka bioloo

Biogas plant

RTI International

Biochar by Pyrolysis

Eco-san

Caltech pv-powered

Nano membrane

Fresh-life

Solar septic

Bioﬁllcom

Blue diversion

Bio-toilet

Earth auger

Two-pit ﬂush

Zero discharge

1 234

Introduction

Theoretical aspects

Elements and processes

Off-grid toilet systems

Comparative classification

Collaborators and Research Team

107

161

PATTERNS

ICONS Nature Solar

Fecal Waste

Slurry

Dried Faeces

Treated Waste

Bio-Char

Faeces refers to (semi-solid) excrement that is not mixed with Urine or water. Each person produces approximately 50 L per year of faecal matter, depending on diet.

Slurry refers in this manual to the muddy mixture of solid and liquid human waste. Is it slightly less contaminated that solid human waste due to its dissolution with liquid waste.

Dried faeces are Faeces that have been dehydrated until they become a dry, crumbly material. It can be obtained by storing faeces in a dry environment, high temperatures and/or by mixing with drying agent.

Treated waste experiences different treatment processes to ensure that waste has the most negligible impact on the environment or can be used as fertilizer.

Biochar is a carbon-rich material produced during the thermochemical decomposition of biomass with a temperature of about ≤700°C in the absence or limited supply of oxygen.

Water

Air

Rain

Windy

Snow

Element Fire

Moisture

Liquid

Odor

Vapor

Activated Carbon

Agents User

Entrepreneur

Operator

Franchisor

Repairman

Women

Make Liquid Waste

Supernatant

Anal Cleansing Water

Grey Liquid

Treated Water

In this manual urine states as, liquid waste. Urine product refers to pure urine that is not mixed with faeces or water. Depending on diet, liquid waste contains approximately 1% of its weight in Nitrogen.

It represents the liquid lying above a solid residue after sedimentation process. This liquid is similarly contaminated, like the faecal sludge. This term also refers to water with a high level of pathogens contamination.

Anal cleansing water is the water resulting of the process of cleaning after defecation. With anal-cleansing water we refer to any water contaminated in a moderate proportion with pathogens coming from human waste.

Volume of water generated from washing and kitchen wash, but not from toilets. It may contain traces of Excreta (e.g., from washing diapers) and, therefore, also traces of pathogens.

Treated water is water that undergoes different filtering processes to become free of pathogens. Over here, this type of water is safe for irrigation, flushing, and washing purposes but not for drinking.

Construct

Maintenanace

DIY Build

Compact

Transport

Storage

Values Health

Circular Economy

Job

Protection

Opportunity

Inclusiveness

Power Heat Solid Fertiliser

Liquid Fertiliser

Drying Agent

Earth Soil

Surface Soil

Solid fertiliser refers to the output produced from human solid waste which can be safely manage as an organic fertiliser to supply nutrients to farmlands.

Liquid fertiliser refers to the output produced from human liquid waste which can be safely manage as organic fertiliser to supply nutrients to farmlands.

This refers to any agent (usually sand, sawdust or ashes) used for reducing the moisture of the solid human waste.

Earth soil is the underneath ground material for holding a septic tank or treatment solution. Often subject to contaminate water infilteration.

Surface soil is the uppermost loose layer of the earth, consisting of organic matter and soil organisms suitable for plant growth.

Gas

Electricity

Power generator

Fuel

Human force

H2 Catalyser

Photovoltaic Panel

Combustion Chamber

Hydrogen Fuel Cell

Devices Stirling Engine

Auger Screw

Processes Aerobic Digestion

Anaerobic Digestion

Filter

Condensation

Processing Plant

Land pollution

Bio Sand Sand is a granular material composed of divided rock and mineral particles. For filtration, 0.35-0.60 mm of silica sand is for its ability to hold back precipitates containing impurities.

Natural Fibre Coconut coir or dried sugarcane are good bulking material for composting toilets. These helps dry out the contents of the solid waste reservoir, facilitates decomposition and neutralizes odors.

Fiber Filter Bacteria embedded fibre materials are also used as filter layers to clear the waste waters of pathogens and harmful bacterias.

Gravel Stone Gravel is usually the first stage in a process called sand filtration. The gravel removes the largest contaminants. For effective filtration, 40 – 65 mm gravel stone is used.

Limestone Limestone filter contains 2/3 sand and 1/3 crushed limestone. They act as a base for changing the water's pH content and help remove iron and its byproducts from the water.

Plantation

Farming

Recyling

Wetland

Bio-waste

Composting

Lines Steps

Steps

Connect

Message

Label

Loop

ABOUT THIS BOOK This book was created unintentionally. The idea appeared at some point during two-year-long research as a logical thing to do. Similarly, collaborators and contributors were found gradually along the different phases of this journey without a partnership established beforehand.

INTRODUCTION

This research started with a funding from the University of Liverpool to explore the sanitation conditions in Karail, one of the densest informal settlements in Dhaka. We have worked in Karail before, studying the phenomenal resilience of their people and the importance that they have for the daily functioning of the accommodated city around it. We tried to understand the dynamic of the social assemblage created there from different perspectives and the macro and micro politics of negotiation inside Karail’s communities and between them and the formal city. When visiting Karail, it is quite surprising to find that the same community that has organised a quite functional informal city lives powerless around an open-air sewage system in which Banani lake has been converted. The lives of Karail’s people don’t look to be apparently affected by the presence of this situation, but data reveal a totally different situation. The under-five mortality in informal settlements in Bangladesh is 79% higher compared to other urban areas and 44% higher than the mortality rate in rural Bangladesh (UNICEF, 2010). Waterborne diseases were highly responsible for this situation, and the lack of sanitation infrastructure is behind it. With the support of the University of Liverpool and the collaboration of the Centre for Inclusive Architecture and Urbanism of BRAC University, a group of young and talented research assistants from Bangladesh was put together to explore how to improve the situation. During the first phase of the research, an in-depth exploration was done in some of Karail’s alleys to understand how inhabitants organise themselves to build toilet facilities.

It was found that people were able to manage quite well the construction of toilets and collecting pipes, but they found it difficult to organise more complex infrastructures such as purification plants. Dumping the untreated waste in the closest water body was the only option available. The construction of off-grid sanitation systems seems to be an option to tackle this problem, so the research team started to explore which of these systems are available and what are their functional principles. It was found that the information about these systems was extremely scattered, and a book compiling all this information would be a necessary tool. It was then decided also to include a comparison between all the available systems based on the different contextual situations where to apply them, as a way to help communities and NGOs decide which case to implement in each situation. To make all this information extremely visual was also an approach intending to make it highly comprehensive and easily accessible to the general public. This is how the idea of this book was born.

HOW TO USE THIS BOOK This book can be used in two different ways. One way to use the book is to go through it in an orderly manner. Starting from the beginning, the reader will find in the Introduction chapter a few texts providing the background information of this problem. The second chapter, Elements and Processes, explains in detail the terms and concepts used in later chapters as a way to better understand the main principles for human waste disinfection. In chapter three, the reader will find a selection of sixteen off-grid Toilet Systems which have been implemented worldwide. In this chapter, an explanation is provided about each of these systems as to how they are, how they work and what are their main advantages and expected precautions. In

the last chapter, Comparative Classification, we explore comparatively how the different systems will adapt to the respective user groups and contextual conditions. This classification would help communities and NGOs to make decisions about the systems that can better accomplish their necessities and fit their conditions.

This cross-navigation system allows readers to create their path across the book depending on their particular interests.

Another way to go through this book is to not follow the sequence chapters but use the cross-navigation references inserted across the chapters. Each chapter has a characteristic colour: grey for the introduction, blue for the elements and processes, yellow for the endnotes endnotes systems, and pink fortoto the classification. CHAPTER CHAPTER 33 CHAPTER 3

11 1

CHAPTER22 CHAPTER CHAPTER 2 CHAPTER 2

11 1

In Chapter three (Off-grid Toilet Systems), a set of numbered grey dots guide the reader across different explanations about the steps involved in the different systems purification processes.

to endnotes

22 2

to endnotes

CHAPTER 3

Across chapters two (Elements and Processes) and three (Off-grid Toilets Systems), the reader will find inserted in the text small colour squares guiding to footnotes which refer to specific pages in the same or other chapters where more information related to a particular keyword can be found.

to toendnotes endnotes to endnotes

to CHAPTER CHAPTER44 to to CHAPTER 4

backin in CHAPTER CHAPTER22 back to endnotes back in CHAPTER 2

to CHAPTER 4

CHAPTER33 to CHAPTER to to CHAPTER 3

back in CHAPTER 2

to CHAPTER 3

CHAPTER CHAPTER44 CHAPTER 4

aa a

CHAPTER 4

11 1

a 1

22 2 2

in in the the page page in the page among among chapters chapters in the page among chapters to to endnotes endnotes // footnotes footnotes chapters to endnotes /among footnotes

to endnotes / footnotes

backin in CHAPTER back CHAPTER33 back in CHAPTER 3

bb b b

to CHAPTER CHAPTER44 to to CHAPTER 4 to CHAPTER 4

back in CHAPTER 3

CHAPTER22 to CHAPTER to to CHAPTER 2 to CHAPTER 2

In all chapters, particularly in chapter four (Comparative Classification), a set of superindexes will conduct the reader to the endnotes and footnotes. The superindex numbers will guide to the endnotes compiled at the end of the book, while the letter superindex letters will take the reader to further explanations in the footnotes on the same page.

to tofootnotes footnotes to footnotes

to toendnotes endnotes to endnotes

to footnotes

to endnotes

ACKNOWLEDGEMENTS This book would not be possible without the support of many organisations, colleagues and friends. Firstly, we would like to thank the Spanish Embassy in Bangladesh, particularly the Ambassador Mr Francisco de Asís Benítez Salas and very especially Ms Emilia Celemin Redondo and her successor Mr Ignacio Siles Fernández-Palacios. Their enthusiasm for the project and their support in our application to the Spanish Agency for International Development Cooperation (AECID)’s grants, were key to giving us the confidence and the financial support to start this project.

Importantly, we would like to express our sincere gratitude to the University of Liverpool for funding our research partly. In particular, Professor Iain Jackson for his continuous support in research. Professor Ola Uduku, Professor Soumyen Bandyopadhyay and Professor Peter Buse for the fundamental support from the School. Dr Andrew Holmes, Dr William Mitchell and Dr Gail Donegan for the support in our ODA Fund application in 2020. Mr David Summersgill, Mr Peter Pimblett, Ms Samantha Hankin from the financial administration support, and Ms Rhianna Mottershaw for the operational support. Ms Tina Lewis, Dr Christopher Williams and Dr Giamila Quattrone for the support of the Wellcome Trust Fund, funds from the Faculty of Humanities & Social Sciences and the School of Arts, University of Liverpool. We are very grateful for the kind support and contribution from Dr Md Khairul Islam, the Regional Director at WaterAid for South Asia. We must thank philanthropist and businessman Mr Tareaq Tareaquzzaman who helped us in crucial moments in this journey. His unconditional support represents the generosity of people from Bangladesh.

We very much appreciate the support from Mr S.M. Shafaiet Mahmud, the backbone of the Centre for Inclusive Architecture and Urbanism (Ci+AU), BRAC University, who provided us with all help needed and hospitability while working in the Centre. We would also like to thank the Director of Altrim Publisher, Ms Ariadna Alvarez Garreta. She believed in this book from the beginning showing her generosity and patience as always. Finally, our most hearthfully thanks goes the people from Karail, in particular to Mustafa, Shamsun Nahar, Ruby, Hasina, Nurjahan, Fokrul, Salim, Ershad, Anjuman, Md. Rafiq, Zubed Ali, Polly, Monowara, Salam, Farida Begum, Sumi, Maleka, Monu Miya, Shahidul, Jannat and Mokto from the Pani Tank Alley; and to Shujiya, Rehana, Shahid, Zolekha, Shima, Yesmin, Ruksana, Akkas, Ainal, Anju, Abdul Rahim and Khayer (who invites us to his elder son’s wedding), from Beltala Mosque Alley. Their kindness and resilience have inspired us deeply.

LETTER OF THE AMBASSADOR OF SPAIN TO BANGLADESH The increase in informal settlements is a global phenomenon that accompanies the growth of urban populations. According to UN-Habitat, 25% of the world's population lives in informal settlements with little or no access to sanitation. The lack of access to drinking water and sanitation leads to a high mortality rate and an exacerbated incidence of disease. The fight to guarantee the right to drinking water and sanitation is one of the significant priorities of the Spanish foreign policy's International Cooperation for Development. The water sector is a strategic priority among our foreign action and cooperation initiatives. It contributes to achieving the 'Sustainable Development Goals' and is key to other human rights (health, education, food) since guaranteeing access to water and sanitation is essential in the fight against poverty. That is why this manual on safe sanitation is a much needed instrument, and the Embassy of Spain is a proud contributor to its publication. Written by a group of researchers led by Spanish Professor Paco Mejías Villatoro, it is a compilation of all the current information on off-grid toilet technology, and compares the identified sanitation systems, making it easier to understand them. This initiative will bring together knowledge that is currently widely scattered and whose sources of reference are rather informal. The compilation will, in a structured manner, make the said knowledge available to affected communities and people who work directly with them to help implement solutions to problems related to sanitation. This is a user-friendly, practical reference manual, especially designed keeping in mind the local communities, NGOs, and authorities involved in sanitation who are responsible for creating and maintaining infrastructures for the same. The authors wanted to create a valuable tool to fight problems linked to water contamination,

the most important of which pertain to public health. The many other challenges faced by the communities and addressed in these pages, relate to the spatial and material constraints within which the people live. Bangladesh and its informal settlements are a pertinent example of all that is needed in this realm and all that still needs to be achieved. The Spanish Embassy in Bangladesh and the Spanish Agency for International Development Cooperation proudly support the publication of this manual that puts under the spotlight a pressing problem, the existing solutions to it, and ways to successfully implement these solutions. Francisco de Asís Benítez Salas Ambassador of Spain to Bangladesh

Theoretical aspects

URBAN POVERTY

GOVERNANCE

INFRASTRUCTURE

INEQUALITIES

SOCIO-POLITICS

This chapter provides an introduction to the multidimensional aspects related to safe sanitation worldwide. It wasn’t intended to provide a depth approach to each aspect but a perception of the connection between the different perspectives to better understand the complexity associated with this problem.

Off-grid Toilets

Theoretical Aspects

URBAN POVERTY URBAN POVERTY

GOVERNANCE

INFRASTRUCTURE

INEQUALITIES

SOCIO-POLITICS

Urban Poverty is a Problem of Social Justice Adnan Z Morshed

Bangladesh has been exemplary in poverty reduction. Thanks to the opportunities that urbanization created, the extreme urban poverty rate came down from 19.9% in 2000 to 8.0% in 2016. Reductions in poverty witnessed improvements in non-monetary aspects of wellbeing, such as reduced child mortality, an increase in life expectancy, and enhanced access to safe drinking water and sanitation, electricity, and education. According to a World Bank report, although 80% of Bangladesh’s poor households live in rural areas now, more than half will live in urban areas by 2030. Urban will be the frontier in poverty reduction.

Urban will be the frontier in poverty reduction.

Despite steady progress in mitigation, urban poverty remains to be a tenacious social and policy problem. There is a paradox. Poverty—if defined as a broad problem of lack of access to economic, social, educational, and healthcare opportunities, and, as the Nobel Laureate Amartya Sen notes, lack of freedoms that enable people to lead the lives they choose—is experienced in the city at many levels and domains, but it is invisible. Or rather there have been concerted efforts by policymakers, municipal or local governments, and

The invisibility of the poor occurs when their agency is not acknowledged as a necessary and powerful catalyst for progress itself. planning communities to make the urban poor invisible by confining them to a ghetto or abstracting them into a monolithic group in need of perpetual support. The invisibility of the poor occurs when their agency is not acknowledged as a necessary and powerful catalyst for progress itself. To frame urban poverty in terms of the inadequacy of urban amenities (such as toilets and piped water supplies) in slums alone is to ignore a deeper social question, perpetuating the disenfranchisement of the urban poor. What remains unasked is: what is society's attitude towards the "poor"? Lest we forget, the idea of poverty has not been static in history. Both the idea and strategies for its relief have changed since the Industrial Revolution and industrial cities grew manifold in the modern era. Consider London, for instance. In the wake of the city's intense urbanisation in the 19th century and the proliferation of the urban poor who

left the countryside and flocked to the city in search of jobs and other opportunities, a highly divisive political and philosophical debate raged about reforming laws related to poor people. Should the poor be the charge of the state? It was hardly a straightforward argument between state responsibility and private charity. In fact, as studies show, in 19th-century London, private charity flourished when public relief for the poor was most generous. At the centre of this vexing debate was this question: would top-down "help" (from the state and wealthy private citizens) diminish the poor's ability to take personal responsibility? So intense a philosophical discussion was it that even the French political philosopher Tocqueville and German philosopher Hegel followed the English turmoil with much fascination.

any empirical study of the poor must be coupled with a fundamental ethical position that the poor is not the Other.

Without compassion as public policy, research tends to calcify the poor as a category, one that is isolated from any decision-making power structures. Without any real agency, this category is on perpetual life support. In his work on gender justice, Amartya Sen argued that real societal progress is made when women's empowerment takes a strong hold on the public's ethical imagination. A similar argument could be made in the case of poverty studies. An ethically based view of the poor as fellow citizens, rather than as an objectified research category, is urgently needed for any sustained alleviation of poverty.

We need to rethink urban poverty as a problem of social justice, not just as a problem of economic development.

It is important to revisit this age-old question, in the context of the rapidly urbanizing cities of Bangladesh, to disrupt the cycle of urban poverty in a sustainable way. What is required is an attitudinal change in policies toward poverty reduction. An empirical understanding of poverty is important for meaningful support for the poor. But any empirical study of the poor must be coupled with a fundamental ethical position that the poor is not the Other. The poor should not be abstracted as a social category — a binary opposite of the bourgeois self — to be quarantined for research and experimentation. While empirical research is essential,

without human compassion it bureaucratises the concept of poverty and dehumanises the poor.

The issue of urban poverty should be examined with a bit of moral quandary and introspection into how the class-conscious bourgeoisie defines itself as the opposite of the poor. This very definition constitutes the central problem in the alleviation of urban poverty. The urban poor, the driver of the city's proverbial informal economy, should not be kept socially invisible behind research, big data, and class walls. The poor must be seen with a human face, not as an abstraction.

Planners and city professionals must debunk the mythology that the poor is a closed social group in

Off-grid Toilets

Theoretical Aspects

need of an improved ghetto. It is important not to forget that the poor are typically stuck in spatial traps, often legitimised through official planning processes. These spatial traps are slums, unsanitary industrial zones, flood-prone riverbanks, and footpaths. By keeping the poor on the urban fringe and in hazardous areas, cities often deny them social justice and access to networks of economic and social mobility. By ghettoising the poor in undesirable, environmentally precarious areas, both cities and capitalistic systems seek to fortify a false sense of social hygiene.

American social justice activist Bryan Stevenson stated, “The opposite of poverty is not wealth but justice.” It is time policymakers, municipal administrators, and urban planners in Bangladesh (and in other countries) rethought urban poverty as a problem of social justice, not just as a problem of economic development. Reference: Sen Amartya. 2001. Development as Freedom. Oxford: Oxford University Press Stevenson Bryam. 2015. Just Mercy: A Story of Justice and Redemption. Melbourne Victoria: Scribe Copyright of the image: Author

Off-grid Toilets

Theoretical Aspects

GOVERNANCE

OVERTY

GOVERNANCE

INFRASTRUCTURE

INEQUALITIES

SOCIO-POLITICS

Md Khairul Islam, Vanita Suneja and Faysal Abbas

economy. About 4.5 million kilograms of human excreta without treatment originating from Dhaka city gets mixed up with river water at more than 600 points across the length and breadth of these four rivers.

In the capital city Dhaka itself, all the four rivers are polluted with wastewater from drains connected directly to the latrines of well-off people of Dhaka city.

Mismanagement of human waste is a prime culprit apart from the industrial pollution that grips the environment. In the capital city Dhaka itself, all the four rivers – Buriganga, Turag, Balu and Tongi canal – are polluted with wastewater from drains connected directly to the latrines of well-off people of Dhaka city. Contamination of water with fecal sludge compromises the health, hygiene and wellbeing of people, environment and shackles the

another one becomes active and filled one auto digests the shits to become organic manure. When the second one becomes full then the first one becomes operational again. In this way, safely managed sanitation chain is maintained. In rural areas according to latest JMP stats, 42% of population is using safely managed sanitation. What is possible in rural areas, is rarely doable in urban context, which is stringed with complications mainly due to high population density. A latrine pit gets full in a few weeks’ time and does not get enough time to auto digests fecal matters. Hence, the fecal matters overflow quickly from the pit resulting polluting the environment.

The real challenge now for Bangladesh is the safe containment and disposal of human waste.

Beyond Latrines: Safely Managed Sanitation Services

Bangladesh is interspersed with rivers, and most of its land plain formed by the magnificent river systems of Ganga, Brahmaputra and Meghna as one of the biggest deltas shaping the culture and history of the country. Rivers as tactical pathways were the allies of the Freedom Fighters in 1971. The Bhatiyali (folk) songs with its pathos are inspired by the depth and vastness of the rivers. As providers of livelihoods, water and food, rivers are central to the life of people in here as it has been for many civilizations. However, over the years, these lifelines of the country are threatened by contaminants gushed out of industries and households.

managed services. One of the critical avenues in achieving this is to understand it clearly. The Joint Monitoring Programme for Water Supply and Sanitation (JMP) states that there are three main ways to meet the criteria for use of a safely managed sanitation service: i) people should use improved sanitation facilities which are not shared with other households; ii) the excreta produced should either be: Treated and disposed on-site; Stored temporarily and then emptied and transported to treatment off-site; Transported through a sewer with wastewater and then treated offsite, and that Human waste needs to be safely managed across the entire sanitation service chain. As shown in sanitation service chain figure (adopted):

Bangladesh has been a pioneer on the open Defecation Free (ODF) status during the Millennium Development Goals (MDGs) way back in 2005. Historically, latrines and toilets largely meant digging a few feet of pit on the ground and containing the human waste, which has been one of the cornerstones of ODF success factors in Bangladesh. While treading towards safely managed sanitation under SDGs the similar mindset of focusing only on latrines and toilets may just make Bangladesh’s success in vain.

Sustainable Development Goal 6 – Clean Water and Sanitation – sets targets for Bangladesh to ensure availability and sustainable management of water and sanitation for all by 2030. However, the new service levels of SDGs need to be well-comprehended to succeed in attaining safely

The extent of the sanitation service chain depends widely on context of the location, for example in slums in Dhaka, the full chain may be required which includes capturing, containment, emptying, transport, and disposal of fecal sludge. Whereas in remote rural settings, latrine pits are often covered when full, which doesn’t require the other sections of the service chain; or they use twin pit latrines – meaning when one pit gets full with shit

While aspirations towards safely managed sanitation is high in Bangladesh, the desire to focus and prioritizing only on latrine is still prominent. The result is the failure of sanitation chain and rampant pollution leading to overwhelming threats to people, environment, and the rivers. An example of this is Dhaka which is surrounded with many rivers, but each river has evolved to be a textbook example of pollution and contamination. This situation demands a clear understanding of the concept of safely managed sanitation service chain in Bangladesh’s context. It’s rapid urbanization which surpasses boundaries of Dhaka shows a future in perils, unless proper attention is given on acknowledging the problem of what safely sanitation really means – as a first step.

Off-grid Toilets

Theoretical Aspects

Upazilas (sub-districts) and small towns are rapidly becoming hubs of economic activities leading to higher demands of housing and space, however if immediate attention is not given towards safely sanitation services – cities in Bangladesh will continue to grow taller, but the human waste it generates will only jeopardize nature and human lives. The real challenge now for Bangladesh is the safe containment and disposal of human waste. The safe disposal needs government interventions and community level awareness at various levels along with right investment which can accelerate safely managed sanitations ambitions. A few quick wins which can contribute towards achieving safely managed sanitation can be as follows:

The Arshayan project I and II of Bangladesh Government is offering house with single pit toilet to many families and focusing on 6.2, reaching to landless and homeless people. If with additional funding all these single pit toilets could be transformed into twin pit latrines, then all of those could be brought under safely managed sanitation. In future this revised design may address the hardcore poor with safely managed sanitation too as a game changer in accelerating SGD targets.

They need to make the policy makers understand that having 100% latrine is not equal to 100% safely managed sanitation

The Government officials responsible for supplying information to the policy makers be honest in updating providing actual scenario in terms of safely managed sanitation situation of the country. Providing a sense of complacence is counterproductive. They need to make the policy makers understand that having 100% latrine is not equal to 100% safely managed sanitation; and explain honestly what it means and what needs to be done. Local Government Division has already demonstrated that lowest two income quintiles population can be served to have safely managed sanitation through a program supported by the World Bank implemented by DPHE and PKSF. This model program needs to be scaled up for the lowest two income quintiles of population in line of India’s Souch Bharat Mission.

CWIS (City wide inclusive sanitation) Cell in DPHE should be turned into Country wide inclusive sanitation cell under the Local Government Division of the Ministry to monitor and support countrywide inclusive and safely managed sanitation, including sludge management for rural areas.

Safe management of sanitation also requires a regulatory mechanism and an enabling environment of incentivizing local government agencies like municipalities to invest not only on infrastructure but also on operation and management in the long run. This also requires a financing mechanism where the users would be ready to pay for the services or brought under taxation mechanism for ensuring safely managed sanitation across the value chain. For public health, reducing environmental impacts and rejuvenation of rivers leading to overall wellbeing it is important to prioritize safely managed sanitation in the country; and for breathing life back to Bhatiyali songs of rivers, people, and life.

Off-grid Toilets

Theoretical Aspects

INFRASTRUCTURE

ANCE

INFRASTRUCTURE

INEQUALITIES

SOCIO-POLITICS

Whose Infrastructure? Junjie Xi

I visited Dhaka for the first time in July 2022. Before departure I had already heard of the famous Padma Bridge (opened in June 2022), the longest bridge over the river Ganges, built by the China Major Bridge Engineering Company. The bridge now connects Dhaka with Kolkata much more quickly, connecting Southern Bangladesh to the capital via a shorter route. With the excitement about seeing “big infrastructure” and “big development” in Dhaka, I was soon stuck in the extremely dense traffic.

we’ve encouraged double the volume of vehicles using the same route.”2 (Figure 1: Passing under one flyover in Dhaka on next page) The construction of these flyovers has attracted great attention from scholars and researchers. For example, the Centre for Inclusive Architecture and Urbanism at BRAC University has undertaken a project entitled “Multi-Purposing Flyovers – A Policy Framework for Elevated Road Infrastructures in Bangladesh”, funded by the United Nations Development Programme (UNDP) in Dhaka. They evaluated the use of the current flyovers in Dhaka and identified how people have used the public spaces beneath the flyovers: informal shops, a mosque, shelters, fish markets, toilets and also prostitution. Experiencing this personally, one day I saw from inside a tuktuk several hijra (transgender people) walking past us towards a flyover and then resting there underneath. It seems that this gigantic urban infrastructure has provided a temporary shelter for them in the city. I understood later that Bangladesh has the oldest transgender community in the world, and hijra are unable to gain regular employment, instead

When “big infrastructure” is being planned, it is easy to lose sight of the people living in the informal parts of the city

From the moment I exited Hazrat Shahjalal International Airport, I saw miles of flyovers being built, leading towards traffic that seemingly has no end. To reduce traffic, Dhaka opened its first flyover in 2004, at a total length of 1.12 km.1 As of 2022, seven flyovers have been built in the city. Dr Shamsul Haque from Bangladesh University of Engineering and Technology argues that there is no proof that the flyovers have added any benefits to the city; during an interview with United News of Bangladesh (UNB), he stated, “We’ve built roads over roads. These won’t help solve the problem. Instead,

Off-grid Toilets

Theoretical Aspects

being forced to support their households through sex work and begging on the streets.3 Building infrastructure has a profound effect on the livelihood of urban dwellers. The ninth United Nations Sustainable Development Goal states the need to: “Build resilient infrastructure, promote inclusive and sustainable industrialization and foster innovation”.4 Through common understanding, the development of infrastructure should reflect the value of a society. When “big infrastructure” is being planned, it is easy to lose sight of the people living in the informal parts of the city, where the most fundamental aspects of infrastructure, such as water supply, sewers and electricity, are not met.

reality has shown a strong resilience from the informal settlements, organised through community governance from below.7 The day before I left Dhaka, I went to the rooftop of BRAC University to see Karail in the evening. Karail is a 15-minute walk from the University, and from a distance the informal settlement was pitch black with some tiny dots of light looking like stars from afar. The lights from the wealthy neighbourhood Gulshan 2 create a contrast with this darkness caused by a lack of electricity. But surprisingly, our research findings suggest that Karail’s electricity bills are four times higher than those in the formal city. The people from Karail are an essential part of the formal city: the majority of women work as maids and cook for the people in Dhaka, and most men are rickshaw pullers, an essential part of “easing” the congested traffic in Dhaka. Although known as part of the city, their lives seem so distanced from benefitting from electricity grids, sewage systems, new roads and bridges. When there is a lack of infrastructure, there is also a lack of schools, housing (either formal or informal), medical assistance and community facilities. Under pressure of being evicted, the people of Karail are too afraid to spend their (already extremely limited) money on building better facilities to connect with the infrastructure.8

Water is distributed to households via a self-organised system of connecting boxes and plastic pipes

Since 2020, our ODA-funded research has led us to study the sanitation system in Karail, the largest informal settlement in Dhaka. The dwellers generally lack land and a clean water supply, as well as adequate sewage. To tackle the problem of a lack of land, new land is being created gradually through landfills curated by the bariwalas (land-owners), paying attention to the area’s hydrology.5 Water is distributed to households via a self-organised system of connecting boxes and plastic pipes. A detailed timetable for obtaining water is in operation through negotiation among the residents. All infrastructures and processes are created and governed from below.6 The recent COVID-19 pandemic has intensified this economic inequality: more uncertainty, loss of livelihoods and financial hardship create even larger challenges for the future. Despite the media’s anticipation of the disastrous impact of the pandemic on the dwellers there, and thus on the rest of the city, the

Another increasing challenge is the climate crisis, which has further deepened the pain of inequality. In the summer of 2022, many countries around the globe, including those in South Asia, experienced the worst droughts in history. Before leaving for the airport, our

friend Mehreen noted how strange it was now that Dhaka was not raining much during the monsoon season. “It was raining like cats and dogs when I was a child,”9 she said. Many global organisations claim that climate impacts are projected to lead to increases in the investment required for infrastructure, particularly water storage, flood defences, water supply and sanitation in some regions. However, whether the dwellers from the informal settlements will benefit from the formally planned infrastructure remains a question. I could not help but still hope: if more meaningful awareness from “grass-roots” occurs, then perhaps a “heavy downpour fall[ing] on the new leaves”10 would return and our hearts would dance again like peacocks.11

References: 1. Rezaul Karim, "PM Opens First Flyover; Promises Many More Structures, Underground Railway," The Daily Star 2004. 2. Saykot Kabir Shayok, "Flyovers in Dhaka: Are They Any Solution to Traffic Gridlock or Scraps?," United News of Bangladesh 2019. 3. Joe Wallen, "Pride and Persecution: The Rise and Fall of the World's Oldest Transgender Community," Telegraph. 4. United Nations, Department of Economic and Social Affairs United Nations and Sustainable Development, "Build Resilient Infrastructure, Promote Inclusive and Sustainable Industrialization and Foster Innovation," https://sdgs.un.org/goals/goal9. 5. Tanzil Shafique and Paco Mejias Villatoro, "Karail: A Social Assemblage in Dhaka’s Center’," in Dhaka Totem (Altrim Publishers & AECID (Spanish Agency for International Development Cooperation), 2019). 6. Junjie Xi et al., "Improving Sanitation Safety through Soft Engineering Design Solutions in Informal Settlements: Karail

(Dhaka) and the Pollution at Banani Lake," (2021). 7. Michael Collyer et al., "Covid-19: Community Resilience in Urban Informal Settlements," (Brighton: Institute of Development Studies, 2021). 8. Junjie Xi et al., "Improving Sanitation Safety through Soft Engineering Design Solutions in Informal Settlements: Karail (Dhaka) and the Pollution at Banani Lake." 9. Mehreen Hossain, 7 August 2022. 10. Rabindranath Tagore, Khanika (1900). 11. Ibid. Copyright of the images: Author

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Theoretical Aspects

from a distance the informal settlement was pitch black with some tiny dots of light looking like stars from afar

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Theoretical Aspects

INEQUALITIES

RUCTURE

INEQUALITIES

SOCIO-POLITICS

Beyond an Eyes-wide-shut View: Understanding the Context of Inequalities using Assemblage Thinking Paco Mejias Villatoro

“Over 1.7 billion people still do not have basic sanitation services, such as private toilets or latrines.” (WHO, 2022)

Facts such as these remind us of the sheer scale of the problem of safe sanitation worldwide, and are perhaps another indication of the staggering inequality with which we are, unfortunately, getting used to living. But how are these inequalities maintained every day? What are the relationalities that sustain them? In this essay, taking an informal settlement in Dhaka as a case study, I would like to introduce the hidden mechanisms supporting inequality and who benefits from it in this specific place, although the lessons would be crucial for any development worker, NGO or anyone else who wants to work in such a settlement. This discussion may appear somewhat theoretical but it is written with the firm conviction that good practice is intricately related to our conceptual frameworks, and the following account should similarly expand the reader’s conception of how sanitation in a settlement is entangled within a complex context.

Dhaka is a city where two contrasting built environments and social realities run in parallel. The city hosts almost 5,000 informal settlements, closely embedded within its formal fabric (Angeles et al., 2009). Unequal cohabitation occurs, with both extremes in close connection to each other, like two different cities with different people and mechanisms, each of them only visible from one perspective, from one particular eye. Karail, with a population of approximately 250,000, is one of the biggest informal settlements in Dhaka and is a neighbour to some of the most affluent neighbourhoods in the city. This makes Karail an ideal place in which to study the mechanism behind this double-sided – or we could say “double-eyed” – reality.

Dhaka is a city where two opposite built environments and social realities are running parallelly

Dhaka’s formal inhabitants have easy access to very cheap labour through a huge number of informal workers living in proximity. Bangladesh is considered to be one of the five countries with the cheapest labour in the world: there is an abundance of diligent workers, able to work day and night just to receive a minimum wage below 250 dollars per year (Basicplanet, 2022). Cooks, chauffeurs, maids, cleaners, rickshaw pullers, babysitters and gatekeepers… these are just some examples of this vast cohort of servants

Off-grid Toilets

making the formal urbanites’ accommodated lifestyles possible. Informal settlers work under harsh conditions without social insurance coverage and within a strict discipline, in a context where a simple mistake could result in them losing their jobs, as replacements are easily obtainable.

Theoretical Aspects

For villagers, national or international displacement represents the hype of a better life, hype that becomes an inequality trap difficult to escape from

Mostly arriving from a rural environment, informal settlers are an unqualified workforce in the city. They are simply raw human force in a country where forced economic migration is one of the most fruitful industries. Almost ten per cent of the migrants going abroad come back in a coffin, due to the even more difficult working conditions in foreign countries (Chaity, 2017). Rural dwellers are often pushed to urban migration due to climate-change disasters, such as severe droughts and floods. For villagers, national or international displacement represents the hype of a better life, a hype that becomes an inequality trap from which it is difficult to escape. When rural migrants arrive in informal urban settlements, the scenario is highly unwelcoming: densities of up to 11 times higher than in the formal city (Angeles et al., 2009), poor and unhealthy living conditions and extremely difficult working conditions. In this new context, unsafe sanitation is part of their daily routines, and is, to a very great extent, responsible for staggering levels of under-five child mortality compared with formal urban areas in Dhaka and even in rural Bangladesh (UNICEF, 2010). Only social networks, frequently created by people from their own villages

who had emigrated previously, offer them some comfort in this brutal scenario.

The formal and informal perspectives comprise two sides of a perverse situation based on a de-facto agreement in which each side depends on the other but under very different conditions. This particular social assemblage (Shafique and Mejias, 2018) is organised to retain inequality as the most radical of its functional principles. The assemblage theory – originally put forward by Deleuze and Guattari (1987) in the late 1980s and later developed by Manuel DeLanda (2016) – is helpful in explaining social relationships. Within this theory, social hierarchies and the different processes involved can either change (referred to as processes of territorialisation and deterritorialisation) or be fixed (processes of codification), in search of more stable assemblages. The three processes defined by Deleuze and Guattari as being involved in social assemblages have established vicious dynamics aiming to perpetuate inequality. The stratification of the bodies involved is inviolable, and the role played by the bottom strata is usually meaningless, due to easy and incontestable replacement. The amount of accessible human force (the material side of the role) and the dismissal of their wellbeing and feelings (the

This particular social assemblage is organised to keep inequality as the most radical of its functional principles.

expressive side) are responsible for the irreversibility of the stratification. For Karail’s people, as representatives of informal dwellers across the world, the relations of interiority (their roles in their communities) and exteriority (their roles outside) are extremely asymmetric. Informal dwellers who are empowered by their communities to participate in the self-organisation and construction of important parts of the city in an exemplary way (roles played through their relations of interiority) feel powerless when they have fragile citizenship as part of the formal city (when they play their role of exteriority). This situation determines further steps in the assemblage chain: the “establishment” manages to make this situation stable for its own benefit (to code it), shielding the situation through active and passive mechanisms. The city is then consequently coded through legal frames, political inaction and economic traps, to make this situation last. In this context, “establishment” refers to everyone aware of these mechanisms and passively sitting on the “comfortable” side of the assemblage, a passivity that makes them accomplices.

uses this vulnerability to its advantage. Without stable conditions, informal dwellers are condemned to be unable to invest in improving their homes: standardised metal sheets used for informal constructions are never cut into smaller pieces, as a way to guarantee the reuse of the material in the case of sudden eviction or brutal demolition. The macabre module of the metal sheet’s dimensions reminds the informal inhabitants that each day could be their last one as a resident of the city. However, the establishment is quite confident that pushing informal inhabitants to this situation will not trigger their collective consciousness, moving them from resignation to resistance and, from there, to rebellion, for two main reasons. First, the establishment has control of the law-enforcement authorities (the force of law, as explained by Derrida, 1992), which are corruptible and extremely effective in intimidating vulnerable communities. Second, the establishment may think, as Banerjee and Duflo (2011) remind us, that “the poor are so absorbed by the problems of the present that they don’t have the mental space to worry about the future” (2011: 8).

The electricity price in Karail is up to four times higher than in the formal city

The codification of this situation and its mechanism of perpetuation has several steps perversely curated, and these need to be explained briefly. In the initial step, informal urban dwellers are trapped by the legal frame, which pushes them towards illegality, making each informal dweller a potential criminal. This unofficially declared condition of squatting means that informal settlers live under a constant threat of eviction, leaving them fearful and powerless. Their lack of education and their unfamiliarity with the urban environment make them especially vulnerable to this threat, a situation that is known and managed by the establishment, which

Once informal dwellers have been pushed to illegality due to land poverty, a second step follows when they are condemned to remain in economic instability. A poverty trap is in place to ensure that informal settlers will never have the means to abandon their lower position in the socio-economic stratification. Keeping them as very low-income individuals is a way to ensure that their income in the future will be even lower than it is in the present, thus they will become poorer and poorer, unable to escape this trap (Banerjee and Duflo, 2011). Informal dwellers are confined to parts of the city where no provision of amenities is in place, which

Off-grid Toilets

Theoretical Aspects

allows gangs to sell illegal access to urban utilities such as water, gas and electricity. The electricity price in Karail is up to four times higher than in the formal city (Xi et al., 2021). As a consequence, during the night the site is relatively darker, surrounded by the glow of the expensive neighbourhoods nearby. A corrupted network of supply company employees, policemen and different administration officials act in coordination with the utility gangs to squeeze informal settlers’ slender income. The unofficially claimed land tenure – the one identifying informal settlers as illegal inhabitants – appears to dissolve when searching for who is responsible for the utilities provision in the informal areas. In the formal city, things work quite differently. The right to own land is attached to the obligation to provide utilities to make it suitable for human inhabitation, and the city administration is empowered to request utility provision before allowing people to live in a newly developed area. In the case of Karail, the original limits of the land owned by the Bangladesh Telecommunication Company have been distorted by informal dwellers through reclamation of the surrounding lake, which makes it even more difficult to determine who is on illegal land and who is not, and whether the land existed originally.

possibilities in the future. In one of my visits to Dhaka in 2017, I had the opportunity to meet Mr Biplob Hossain, Karail’s first child to graduate from a university, but he is an exception. Hossain’s struggle to achieve a university degree and get a job, simply because he lived in a “slum”, demonstrated the inviolability of the borders of inequality. Only Hossain’s exceptional determination was able to guide him to success, an exceptionality that is difficult to teach as a model to follow. It is unethical to show Karail’s children a barely achievable possibility.

The rural-to-urban displacement is facilitated by the lack of investment in the rural environment

Threatened by eviction and under exceptional economic stress, informal dwellers tend to have bigger families, thinking that new hands will bring new income. With 63% of the families containing six people or more (Amimul Ehsan, 2012), Karail’s children are sent to work in uncontrolled informal occupations. Not attending school brings with it the final and most definite trap: education poverty, which means a definitive lack of

This paper concludes with a brief explanation as to how the codification system works, and the mechanisms put in place to guarantee cyclical perpetuation. At the beginning of this cycle, the rural-to-urban displacement is ensured by the lack of investment in the rural environment. A lack of quality in educational facilities and the absence of public services and agricultural and farming innovations make villagers vulnerable to unexpected disasters and render the rural environments unattractive. The lack of facilities in rural villages is a passive way in which to promote urban-to-rural displacements in support of fast urban industrialisation. This is an unwise strategy, particularly in places like Bangladesh, with labour-intense agriculture (more than 40% of the workforce is devoted to agriculture – CIA, 2022) and a poorly diversified industrial sector (with the textile industry representing 80% of Bangladesh’s total exports –Reuters, 2013). This data, combined with the fact that Bangladesh is one of the countries most affected by climate-change catastrophes (seventh in the list worldwide – Eckstein et al., 2020), creates the perfect storm for promoting human displacement from rural to urban environments.

Once in the city, the migrant communities find new insecurities, coded again to become permanent. The deliberate ambiguity of the land tenure renders the declaration of squatting conditions somewhat arbitrary, empowering the establishment to declare rural migrants illegal, leaving them in an incontestable condition of legal vulnerability. This fragility adds to the economic situation, as a consequence of the low wages and the lack of labour rights, both situations supported by the perversely constructed statement of rural migrants as being illegal citizens. The lack of land-tenure security creates, at the same time, a lack of investment in infrastructure. For informal dwellers, the constant threat of eviction discourages them from investing in improving their inhabitation conditions. For the formal establishment, which claims land tenure, the infrastructural dismissal is a way in which to remind informal dwellers of their unstable citizenship and the fact that settling down in their dwellings is not an option. If informal dwellers were to see infrastructural improvements taking place in the land that they inhabited, the system based on the hype of their illegality would fall apart. The lack of infrastructural improvement brings health vulnerability, eliciting staggering inequalities in mortality rates, perpetuated by the unreachability of public health for the “squatter” dwellers. This same lack of infrastructure facilitates the economic abuse of informal settlers, who need to pay for expensive illegal access to urban utilities. As a result of land insecurity, various vulnerabilities (legal, economic and health) and financial abuse, the families of informal settlers struggle to survive and thus aim to increase the household income by increasing the number of family members.

As a result, child labour is rampant, codified by the lack of adequate child protection policies or a laxity in applying them. An uneducated human workforce with limited possibilities to progress in the future becomes trapped in this vicious cycle. Even if they finally decide to return to their villages, they would do so without better education, meaning that they would be trapped again in the same cycle. As a body of knowledge and practices, sanitation and hygiene also operate within such complex trajectories and cyclical reinforcement of inequalities. Without a more structural response to these conditions, improving toilet facilities alone would not enable the creation of better living conditions. Clear statements about land tenure, providing land security for informal dwellers; greater attention to informal working conditions, in order to avoid the extremely low wages; a stronger determination to battle corruption in order to stop the abuse of informal citizens; wider access to public health; and stronger policies against child labour are all possible solutions for decoding this situation and making a change. The consequences of such changes for the urban establishment are unpredictable, and so fierce resistance is expected on this path to equality. However, these changes would bring informal settlers a subtle but radical change – simply hope for a better future.

these changes would bring a subtle but radical change – simply hope for a better future.

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Theoretical Aspects

The diagram on the left reflects the expected path of a hopeful

CLIMATE CHANGE DISASTERS

migration (in blue) and the chain of vulnerabilities and abuse

RURAL BANGLADESH

blighting this path (in red). If you were to look at this diagram

High human-force based rural production; High quantity of unskilled workers

LACK OF RURAL INVESTMENT

Low production, economic fragility, poor education

you would observe, when closing one eye or the other, the violent

PROMISE LAND

EMIGRATION

IMMIGRATION

wearing a pair of glasses with one side red and the other blue,

BACK HOME WEALTHER

URBAN SETTING

RESIGNATION 29

VULNERABILITIES ABUSE DEFINITIVE TRAPS

INFORMAL JOBS

PLENTY OF UNSKILLED JOBS

PERMANENT JOB

EDUCATION

BACK HOME UNEDUCATED JOB SECURITY

FORMAL URBANSHIP

BACK HOME POORER

JOB INSECURITY

INFORMAL LAND

BACK HOME UNHEALTHY

LAND INSECURITY

A big quantity of workers make unskilled jobs very cheap and fragile: Workers can be easily replaced

Land under unclear definition allows declaration of illegality and promote lack of investment in infrastructures

ECONOMIC STABILITY

LEGAL STABILTY

LEGAL VULNERABILITY

ECONOMIC VULNERABILITY

Unskilled workers must accept poor wages and hard working conditions

ECONOMIC ABUSE

Declared as illegal, living in places without proper infrastructures, informal settlers need to pay more for urban utilities

LONG-LIFE POVERTY

NEED for MORE INCOME Informal settlers have bigger families for getting more wages per household

HARDSHIP

LAND TENURE

HEALTH VULNERABILITY

Declared as illegal in the city, informal settlers live under constant threat of eviction

Without infrastructural provision, informal settlers are forced to live under unhealthy conditions (high under-five mortality)

HUMAN ABUSE

POOR PUBLIC HEALTH PROVISION

Prostitution, Adictions, Mental unhealth

JAIL

ADICTIONS

MADNESS

CHILD LABOUR Informal workers

EDUCATION

LACK of EDUCATION

PROSPERITY

URBAN DREAMS

As illegal, informal settlers have few opportunities to access to a slim public health system

DEATH

STABILITIES

friction of this assemblage.

References: Amimul Ehsan, M., 2012. Karail: A Land for Informal Urbanism. LAP Lambert Academic Publishing Angeles, G., Lance, P., Barden-O’Fallon, J., Islam, N., Mahbub, A.Q.M. and Nurul Islam Nazem, N.I., 2009. “The 2005 census and mapping of slums in Bangladesh: design, select, results and application”. International Journal of Health Geographics, 8:32, available at: www.ij-healthgeographics.com/content/8/1/32 Banerjee, A.V. and Duflo, E., 2011. Poor Economics: A Radical Rethinking of the Way to Fight Global Poverty. New York: Public Affairs Basicplanet, 2022. “Top 15 countries with cheapest labour in the world”, available at: www.basicplanet.com/top-15-countries-withcheapest-labour-in-the-world/#google_vignette Chaity, A.J., 2017. “Migrant workers’ dreams end in body bags”, Dhaka Tribune, 17 December 2017, available at: https://archive. dhakatribune.com/opinion/special/2017/12/18/migrant-workersdeath CIA, 2022. “Explore all countries: Bangladesh – South Asia”, The World Factbook, available at: www.cia.gov/the-world-factbook/ countries/bangladesh DeLanda, M., 2016. Assemblage Theory. Edinburgh: Edinburgh University Press Deleuze, G. and Guattari, F., 2013 [1987]. A Thousand Plateaus: Capitalism and Schizophrenia. New York: Bloomsbury USA Academic Derrida, J., 1992. “Force of law: the ‘mystical foundation of

authority’”. In: Cornell, D., Rosenfeld, M. and Gray Carlson, D. (eds), Deconstruction and the Possibility of Justice. New York: Routledge Eckstein, D., Künzel, V., Schäfer, L. and Winges, M., 2020. “Global Climate Risk Index: Who suffers most from extreme weather events? Weather-related loss events in 2018 and 1999 to 2018”, German Watch, available at: www.germanwatch.org/sites/germanwatch. org/files/20-2-01e%20Global%20Climate%20Risk%20Index%20 2020_14.pdf Reuters, 2013. “Bangladesh Sept exports soar 36 pct on garment sales”, available at: www.reuters.com/article/bangladesheconomy-exports-idUSL6N0HZ1TV20131009 Shafique, T. and Mejias Villatoro, P., 2018. “Karail: a social assemblage in Dhaka’s centre”. In: Lopez Garcia, A. (ed), Dhaka Totem. Barcelona: Altrim Publishers and AECID UNICEF, 2010. “Understanding urban inequalities in Bangladesh: A prerequisite for achieving Vision 2021”, available at: www. indiaenvironmentportal.org.in/files/Urban_paper_lowres.pdf Xi, J., Morshed, A., Mejias Villatoro, P. and Shafique, T., 2021. “Improving sanitation safety through soft engineering design solutions in informal settlements: Karail (Dhaka) and the pollution at Banani Lake”, ODA Research Seed Funds 2020–2021, University of Liverpool Copyright of the image: Tanzil Shafique Copyright of the diagram: Author

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Theoretical Aspects

SOCIO-POLITICS

ALITIES

SOCIO-POLITICS

Learning Everyday Operational Logics of Sanitation from Karail, Dhaka Tanzil Shafique

“Access to water and sanitation are recognised by the United Nations as human rights, reflecting the fundamental nature of these basics in every person’s life. Lack of access to safe, sufficient and affordable water, sanitation and hygiene facilities has a devastating effect on the health, dignity and prosperity of billions of people, and has significant consequences for the realisation of other human rights.” - UN Water (2022). However, more than 1.7 billion people worldwide do not have access to improved sanitation (WHO 2022). Every year more than a million people die from diarrhoeal disease, mainly caused by unsafe sanitation (WHO 2012). It is quite clear sanitation is such a basic requirement, and yet, it was the worst performer in the Millenium Development Goals, the predecessor of SDGs. Providing sanitation infrastructure has been a critical goal for many international aid agencies, and their local counterparts. One must wonder why it remains a problem even after many years of intervention. Joshi, Fawcett and Mannan’s study (2011) across four different global South cities show the existence of discrepancies between what is considered as best sanitation practices by outsiders/global North standards, and the everyday sanitation needs and uses. In other words, externally funded and built projects often fail in the long term since the infrastructural interventions do not take into consideration the complex entanglements of everyday

social, economic, ecological and technical aspects of sanitation. During my research engagement with informal settlements, one particular story that I learned points to this exact problem. An NGO had come and built new toilet cubicles that were designed and built by experts. With the abundance of funding, the toilet was fitted with strong, sturdy and expensive metal doors. Two weeks after its completion, NGO workers found the doors missing, and a flimsy curtain was put in its stead. Why? Surely they sold it for the money? The answer was more complex than that. These shared toilets were located in communal areas, and often, it was unsafe for women to use the toilet, particularly because of the strong metal doors. The doors could be bolted from inside, and hence one could follow the women into the cubicle and shut it from inside. With a flimsy curtain, it was more difficult, and hence safer. So, the local dwellers got together, pried open the metal doors, sold them off and put up the curtains. The story points out that sanitation is not just about the technical or material aspects brought by experts from outside, it is also about the lived experience with all its social complexities: cultures, norms, belief, rituals, and desires. However, studies/projects in sanitation often are from particular disciplines and often create ‘academic’ knowledge without any direct impact on the struggles

for better sanitation on the ground. Iossifova (2020) argues that “theoretical and practical assumptions in relation to sanitation must be challenged from the ground up in order to develop a rich understanding of sanitation needs, challenges and the possibility for future alternatives to standard sanitation interventions. In the context of mounting ecological, economic and political crises, a unified approach to the study of sanitation which takes into account culture, identity and representation as well as predominant economic and ecological processes across a multitude of scales is needed.” This essay, in line with such an understanding, focuses on the socio-political aspects of sanitation. Without understanding these intricate ways sanitation works in precarious places, we will not be able to intervene in a meaningful and sustainable way. Understanding these entanglements calls for a study of the “soft aspects of everyday sanitation” (Iossifova 2015), the intangible and hidden logics of operation that structure human practice. For this essay here, I will be elaborating on some learnings from the informal settlement of Karail, where I conducted my PhD ethnographic fieldwork, as well as supervised further research. Karail is the largest settlement in Dhaka with a population of around 250,000. The built area map (500 m x 500 m) below shows the western edge of the settlement, where 5 key neighbourhoods were studied in detail.

Each of these areas was further mapped in terms of its sanitation infrastructure, particularly toilets. Three categories of infrastructure were identified: NGO built toilet, self-built toilet, and a wash area for bathing. The maps clearly shows that sanitation infrastructure is somewhat equally distributed across the settlement, with roughly a toilet available for every 30-40 people. The sewage is usually collected by communally shared pipes and disposed of either in the main sewerage line or in the adjacent water body. While the maps are useful to show the spatiality of the toilet infrastructure, the sociopolitical logic remains unexplained. How do people ensure access to sanitation in such a dense environment? How do they manage to share on time? What are the issues related to the everyday lived experience? How does sanitation work in reality? What are relationalities that produce, maintain better sanitation conditions or in many cases, can’t?

The story points out that sanitation is not just about the technical or material aspects brought by experts from outside, but it is also about the lived experience with all its social complexities: cultures, norms, belief, rituals, and desires.

Based on 40 interviews in two of the areas above, the following domains of operating logic/norms were identified that provide a glimpse into how sanitation is practised: 1 Everyday uses and non-uses 2 Power and position 3 Life experiences and events 4 External agents

Off-grid Toilets

Theoretical Aspects

Sanitation infrastructure in informal settlement of Karail, Dhaka

Street Site Locations (500x500m)

3 1

Poshchimpara

Beltola

3 Satellite Poshchim 4

Mosharof Bazar

Bou Bazar

Service Distribution (50x100m) NGO Built toilet block Self-built toilet Stove point

5 0

Poshchimpara

Beltola

Satellite Poshchim

100m

Mosharof Bazar

Power and position

A key factor determining everyday use is the socially acceptable limit of toilet sharing capacity, the number of families/people that can share a number of toilets. The number in Karail appears to be a ratio of 1:35, based on the mapping. This was further corroborated in the interviews, where renters said they look for the toilet facilities in relation to the number of rooms. This impacts the number of rooms in a cluster (each with an avg occupancy of 4), which often means housing clusters are built in multiples of 8 rooms, so as to maximise the return on the investment made in the toilet (toilets are the most expensive part of the house).

The socio-political stratification within the settlement impact access to sanitation and clean water. Local leaders often become service-providing ventures, as they have stronger ties with government and NGO officials. Dwellers with ties to these leaders often will get preferential treatment in service facilities in terms of use and allocation. For example, in Karail, landlords often have more say in how toilets are to be used and renters often have to accept the terms. Moreover, amongst landlords, toilets are often sold and purchased in terms of its usage rights, which explains why some households are without a toilet in their house, but may be using another facility in close proximity, which was built/bought separately. Beyond social positions, the actual spatial position of one’s house often impacts sanitation condition, in what can be termed as ‘conveniences of proximity’. Due to the uneven distribution of resources in the settlement, some people may be closer to infrastructure that may impact their sanitation practices. In Karail, the best sanitation infrastructure often is found in the local mosques. Those who live around the mosque often is able to negotiate access to these infrastructures, eg. adding their own household waste pipe to the mosque’s main line.

However, toilet breakdowns are common and often the only toilet in the housing cluster is out of order. That’s when social capital comes into play. Social capital here is understood as the collective value of all social networks (who people know), and the inclinations that arise from these networks to do things for each other (norms of reciprocity) (Sander 2002). Using the neighbour’s toilet is a key norm that allows the neighbourhood as a whole to function. One interviewee jokingly told us they liked the toilet of one of the neighbours, hence, was always kind to him, just in case he needed to use the toilet in the morning!

Wash area

Everyday uses and non-uses

Some interviewees suggested that they preferred using their workplace toilet/bathing facilities, particularly those who worked as house help and in offices. More than ease of access to those facilities, the decision is also partially due to the high cost of water, which they would have to spend if facilities were used at home more. Hence, not using is often intentional and planned.

Bou Bazar 0

25m

Life experiences and events It is important to see sanitation as a human practice that is embedded in the cultural, and biographical trajectory. In other words, previous life experiences often play a role in how a toilet is viewed and constructed. Therefore, the standard of toilet is subjective but dependent on the previous toilet experience. People who arrived from the villages and those who have been in the City for a long time have different perceptions about hygiene and whatis

Off-grid Toilets

acceptable in terms of sanitation infrastructure. Understanding this perception differential is crucial in proposing new toilet infrastructure. Similarly, certain life events often act as a trigger for dwellers to construct new toilets or upgrade the existing ones. For example, many interviewees mentioned that pregnancy is a trigger for building/upgrading toilets as that is when sharing a toilet becomes more difficult. This points to differences in desire in terms of sanitation and how it can change, thereby fluctuating the need of an community. External agents

While the socio-political factor described so far concerns the dwellers themselves, the last domain is in relation to external agents involved in the sanitation infrastructure process in the community. In the case of Karail, it was various Non-government organisations (NGOs). Evidence from Karail points out the complex nature of these relationships and their consequences. For example, given that NGOs often have strict rules about who is eligible for a new toilet or upgrade, some dwellers purposefully have kept their toilet in an undesirable condition to ensure they are included in the benefit. Some dwellers have used their political positions to ensure that the NGO-funded toilets end up in their house, and if not, at least in close proximity. In some cases in Karail, the dweller has built new housing units around the communal toilet in a form of encroachment and some even have built on top of it. These are not without the knowledge of local NGO workers but there seems to be no repercussions against these internal encroachments.

Theoretical Aspects

Lastly, some NGOs have started using microfinance as a way to finance new toilets, but that is not without its own pitfalls. While anecdotal, these point to complex interrelationships with external agents that impact how santiation infrastructure is used and abused in an informal settlement. The goal in this essay has not been to develop a comprehensive framework in determining how the socio-political entanglements impact sanitation but rather to point to the necessity for examining them before sanitation interventions are planned and executed. Every settlement is different with its own set of idiosyncrasies and only grounded research can reveal its operating logics. References Iossifova, D. (2020). Urban (Sanitation) Transformation in China: a Toilet Revolution and its socio-eco-technical entanglements. In Urban transformations and public health in the emergent city (pp. 102-122). Manchester University Press. Iossifova, D. (2015). Everyday practices of sanitation under uneven urban development in contemporary Shanghai. Environment and Urbanisation, 27(2), 541-554. Sander, T. H. (2002). Social capital and new urbanism: Leading a civic horse to water? National civic review, 91(3), 213-235. WHO. (2022). Sanitation Fact Sheet. Retrieved from https://www.who.int/news-room/fact-sheets/detail/ sanitation#:~:text=In%202020%2C%2054%25%20of%20 the,as%20private%20toilets%20or%20latrines. Copyright of the map and image: Tanzil Shafique

Elements and Processes

HUMAN SOLID WASTE

HUMAN LIQUID WASTE

DIVERSION

SEPARATION

FILTRATION

PLANT-BASED FILTRATION

DISINFECTION

DIGESTION: AEROBIC

DIGESTION: ANAEROBIC

BIO-DIGESTERS

COMPOSTING

ENERGY

CONVERSION ELECTROLYSIS

CIRCULAR ECONOMY

This chapter explains the elements and processes involved in human waste disinfection, which take part in the selected off-grid toilets in this book. These explanations will help the reader to familiarise themselves with the terminology used in the description of the case studies.

Off-grid Toilets

Elements and Processes

HUMAN SOLID WASTE

What is human feces or solid waste?

Human feces is the solid or semisolid remains of food that could not be digested or absorbed in the small intestine of humans but has been further broken down by bacteria in the large intestine. It also contains bacteria and a relatively small amount of metabolic waste products such as bacterially altered bilirubin, and the dead epithelial cells from the lining of the gut. It is discharged through the anus during a process called defecation. Faecal solids are composed of proteins, fats, fibre, bacterial biomass, inorganic materials, and carbohydrates. Their chemical and physical characteristics vary widely depending on a person's health and diet.

1% PROTEIN 4% FATS 4% SALTS 8% DEAD BACTERIA 8% INDIGESTIBLE FIBERS

The World Health Organisation estimates that inadequate sanitation causes 432,000 diarrheal deaths annually. SOLID 25%

WATER 75%

A pathogen is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a germ. There are over 100 different varieties of viruses, bacteria, and helminthes in feces. Some of the systems compiled in this book deliver untreated waste which need further processes to be managed safely. This represent a health hazard. 1 (See each system’s outputs, 1 )

90% (10,000,000) Viruses 9% (1,000,000) Bacteria 0.75% (1,000) Parasite cysts 0.25% (100) Parasitic eggs About 130 to 520 grams of feces are excreted by a human adult daily.

Protein and fat come from the colon due to secretion, epithelial shedding and gut bacterial action. These proportions vary considerably depending on many factors such as mainly diet and body weight.

FAECES PH RANGES BETWEEN 5.3-7.5

A pH value 7 is neutral. Content with a pH value below 7 is considered acidic and above 7 is alkaline. Therefore human solid waste is considered to be slightly acidic. 1_Disinfection #51

(virus)

Polioviruses Hepatitis A Virus Rotaviruses

Poliomyelitis Hepatitis Diarrhea

(protozoal pathogen virus)

Giardia lambia Balantidium coli Entamoeba histolytica

Ulcer

(bacteria)

Campylobacter Pathogenic E.Coli Salmonella typhi Para typhi Typhoid Other salmonella Dystentry Shigella V. Cholera Cholera (these are some pathogens creating notable diseases)

75% moisture FECAL WASTE (RAW) 25% solid DRIED FECAL

40% moisture 60% solid

TREATED WASTE

08% moisture 92% solid

CHARRED WASTE

00% moisture 100% solid

1_Aerosan, #69; Biogas Plan, #77; Caltech PV-Powered, #83; Blue Diversion, #81.

Reuse of human excreta:

There is a large and growing number of disinfection treatments (see disinfection process, 1 ), to make excreta safe and manageable for the intended reuse option. Various technologies and practices (see technology types, 2 ), ranging in scale from a single rural household to a city, can be used to capture potentially valuable resources and make them available for safe, productive uses that support human well-being and broader sustainability.

1_Technology/Type, #143. 2_Expense/Efficiency, #127.

Off-grid Toilets

Elements and Processes

HUMAN LIQUID WASTE

In 2019, more than 404.6 million individuals had UTIs globally, and nearly 236,786 people died of UTIs, contributing to 5.2 million.

What is human urine or liquid waste?

Urine is a liquid by-product of metabolism in humans and many other animals. Urine plays an important role in the earth's nitrogen cycle. For balanced ecosystems, urine fertilizes the soil and thus helps plants to grow. Therefore, urine can be used as a fertilizer. (Systems using liquid waste as liquid fertiliser on-site, 1 ).

0.01% MAGNESIUM 0.015% CALCIUM 0.03% URIC ACID 0.05% AMMONIA 0.1% SODIUM 0.1% CREATININE 0.12% PHOSPHATE 0.18% SULPHATE 0.6% POTASSIUM 0.6% CHLORIDE 2% UREA URINE PH RANGES BETWEEN 0-14

WATER 95%

There are relatively few diseases that are transmitted by urine compared with the myriad of diseases caused by the faecal route. Two well-known diseases that can be spread through urine include typhoid and urinary schistosomiasis.

Up to 10,000 colonies of bacteria/ml are considered normal. Greater than 100,000 colonies/ml represents urinary tract infection.

The normal range for 24-hour urine volume is 800 to 2,000 milliliters per day (with a normal fluid intake of about 2 liters per day). Urine changes can happen for different reasons and are typically seen as changes in the color, smell or consistency of your urine. Often harmless, these changes can be caused by your diet or medications.

A pH of 7 is neutral, whereas a pH result below 7 is acidic and above 7 is alkaline. Urine has the highest range of pH compared to other bodily fluids. 1_Urine-diverting Pan #43

(virus)

Polyomavirus Cytomegalovirus Adenoviruses Hepatitis

Poliomyelitis Hepatitis

(bacteria)

Mychobacteria Salmonella typhi Paratyphi Leptospira interrogans (Fungi Helminths)

Schistosoma haematobium

Typhoid

The hygiene risk of fresh human urine is low, as it is commonly assumed not to transport pathogens. Urine is filtered in the kidneys and is sterile until it passes through the urinarytract, where it comes in contact with comparatively harmless germs (including lactobacilli). Because of this, using urine-diverting pans 1 reduces considerably the quantity of infected waste (Systems using it, 2 ).

Reuse of human urine:

RAW URINE

01% Pathogens 99% Clear

GREY LIQUID

05% Bacteria 95% Clear

CLEAR WATER

00% Bacteria 100% Clear

1_Eco-San, #87; Earth Auger, #85.

Research into how to make reuse of urine and feces safe in agriculture has been carried out in Sweden since the 1990s. To take advantage of the nutrients passed in urine, it can be recycled as fertiliser for agriculture (see Systems’ outputs, 1 ). Research has shown that urine can effectively be used as an alternative to conventional fertiliser. In fact, urine produced by people worldwide contains enough nutrients to fertilise three-quarters of the food we eat.

1_Expense/Efficiency, #127.

Off-grid Toilets

Elements and Processes

DIVERSION

What is an urine-diversion toilet?

A urine-diverting pan is used to divert urine from feces before they contact each other. Some urine-diverting pans may provide a particular inlet as well for cleansing water separately from urine, for facilitating disinfection processes (see Human Liquid Waste in this chapter, 1 ). The main advantage of separating feces and urine is the reduction of pathogens from urine. If anal cleansing takes place with water, then this anal cleansing water must be drained separately to prevent any bacterial contamination by mixing with feces or urine. Dry cover material is usually added to the feces chamber directly after each defecation. This type of diverting excreta management system is an alternative solution to pit latrines and flush toilets, especially in some cases such as: -Locations where water is scarce; where a connection to a sewer system and centralized wastewater treatment plant is not feasible or desired; -Places where fertilizer and soil conditioner are needed for agriculture; or where groundwater pollution needs to be minimized. (See systems using urine-diverting pan , 1 ).

Where does the urine can go?

Figure A

Figure B

How to use a urine-diverting toilet?

Some urine-diverting toilets are simply a pan with two or three three different entrances connected to different tanks, The models with two entrances (such the one shown in Figure C), need to avoid water cleaning for taking advantage of the dry solid waste (easier to disinfect), and the pathogen-free urine. Other models, such as the one shown in Figure A, display three entrances: one for solid waste, a second one for liquid waste, and a third hole for collecting anal-cleansing water. To separate anal-cleansing water and urine is essential for avoiding urine contamination to manage it safely. Other urine-diverting models function based on a particular section able to separate liquid and solid waste in a more passive way (such as the ones in Figure B and Figure D). Separate flushing for the parts collecting solid and liquid waste keep the advantages of collecting disinfected urine and a drier solid waste than with a full flushing.

Why an urine-diversion toilet?

Reasons for keeping urine and feces separate compared to the case of a pit latrine are to:

Urine diverting pans improve the efficiency of the systems and optimise the efficiency of the system to obtain safe to manage outputs. (see Expense/Efficiency, 1 ).

-Reduce odor (mixing urine and feces together causes substantial odor); -Avoid the production of wet, odorous fecal sludge, which has to be removed by someone when the pit latrine is full.

Society and culture: hurdles for acceptance

-Enable fast drying of feces which makes the handling of feces far simpler and more hygienic. -Reduce environmental impacts by allowing the recovery of urine, which can be easily reused as liquid fertilizer, and the recovery of desiccated feces, which can be reused as a soil enhancement.

The urine could be led out in a urine hose to, an infiltration into the ground or a collection vessel. It is recommended connecting an ejector tank where the urine is automatically diluted with water to the right mixture, eight parts water and one part urine, so that plants can absorb the nutrients without being damaged.

Figure C

Figure D 1_Human Liquid Waste, #41.

This waste management system requires some training in order to understand the importance of using it properly. Also, children and conservative adults may have some difficulties in understanding how to use the diverting pan. Accepting and using the system properly is essential for it to prove efficient. (see User/Profile, 2 ).

1_Biochar, #73; Blue Diversion, #81; Eco San, #87; Fresh Life, #89.

1_Expense/Efficiency, #127. 2_User/Profile, #117.

Off-grid Toilets

Elements and Processes

SEPARATION Slurry

Supernatant

What is a auger screw or conveyor?

What is a Centrifugal Force?

A screw conveyor or auger conveyor is a mechanism that uses a rotating helical screw blade, usually within a tube, to move liquid or granular materials. Screw conveyors in modern industry are often used horizontally or at a slight incline as an efficient way to move semi-solid materials. The first type of screw conveyor was the Archimedes' screw, used since ancient times to pump irrigation water. Screw conveyors can be operated with the flow of material inclined upward. When space allows, this is a very economical method of elevating and conveying. As the angle of inclination increases, the capacity of a given unit rapidly decreases. The rotating part of the conveyor is sometimes called simply an auger. (Systems using Auger screws, 1 ).

Solid Waste

Centrifugal force is the apparent force that is felt by an object moving in a curved path that acts outwardly away from the center of rotation. Centrifugal force will cause any particles that have a higher mass to move towards the periphery. Also, the greater the difference in mass, the faster they move. The difference of intensity in the centrifugal forces depending of the mass, is the principle used by the centrifugal separator in the system Zero Discharge ( 3 ). The graphic on the left shows how the combination between the weight of the waste (W) and the centrifugal forces (C) produced by the rotation of the waste inside the centrifugal separator, provides different force vectors for the solid and the liquid waste. These different vectors move the waste in different directions depending on the mass, resulting in separating solid and liquid waste effectively.

What is Sedimentation Process?

Sedimentation is a physical water treatment process. It is the accumulation of solids, or sludge, cast at the bottom of the sedimentation tank, and solid particles are removed periodically. In wastewater treatment plants, particles are removed by this method. Coagulants are typically added to the water before sedimentation to aid in the settling process. After sedimentation, there are often other treatment steps.

What is a liquid displacement chamber?

Gas

Gases have small densities, and therefore they can easily replace higher density fluids like water. This method of displacing water can be used to collect insoluble gases like methane which then can be stored to use for heating or cooking purposes.

Water

Sedimentation of water is one of the most basic processes of purifying water. It may be used as a preliminary step in some water treatment processes. It provides the following benefits: -Fewer chemicals are required for subsequent water treatment. -It makes any subsequent process easier. -The cost is lower than some other methods. -There is less variation in the water quality that goes through the process. (Systems using sedimentation process, 2 ).

Digester

Gas Collection Chamber

Water Collector

The setup for the collection of gas over water involves a con tainer in which the reaction takes place, i.e. the Biodigester, and a gas collection container filled with water and placed upside down in a reservoir of water. The gas evolved from the Biodigester is collected by attaching one end of a hose to the Biodigester container and inserting the other up into the inverted gas collection container. As the gas is created, it displaces water from the container. The volume of gas can be determined by the amount of water that was displaced by the gas. (Systems using displacement chamber, 4 ).

1_Earth Auger, #85; Nano Membrane, #91; RTI International, #93. 2_Banka Bio-loo, #71; Biotoilet, #79; Caltech PV Powered, #83; Nano Membrane, #91, Solar Septic, #95. 3_Zero Discharge, #99. 4_Bio gas Plant, #77.

Off-grid Toilets

Elements and Processes

FILTRATION

Biologically Activated Membrane Bioreactor (BAMBi) Biologically Activated Membrane Bioreactors for wastewater treatment are a combination of a biological treatment method, with membrane filtration equipment– typically low-pressure microfiltration (MF) or ultrafiltration (UF) membranes. Due to the combination of bioreactor and membrane, this system is called a Biologically Activated Membrane Bioreactor (BAMBi) (system using biologically activated membranes, 1 ). The membrane is simply a two-dimensional material used to perform the function of solid-liquid separation ( systems using filtration, 2 ).

There are three stages in the process of using this bioreactor. First, the wastewater needs to pass through a fine screening process or a sedimentation process (see Sedimentation, 1 ). The second stage is in the membrane bioreactor where the combination of biological and filtration process is used. And lastly, occurs the post-disinfection (see Disinfection, 2 ) where Granular Activated Carbon (GAC) and electrolysis 3 processes are employed.

How does a BAMBi work?

Granular activated carbon (GAC):

Aeration Pump

Granular activated carbon

Bioreactor

GAC adsorbs the chemical due to its porous qualities

Ultrafiltration membrane

The wastewater is pumped into a Bioreactor where with the help of an ultrafiltration membrane (porous filter medium of 0.005 to 0.1 micron) solid particles are held back on the filter surface and the liquid portion passes through it. Air is introduced through integral diffusers to continually scour membrane surfaces during filtration, facilitate mixing, and contribute oxygen to the biological process. Airflow also helps to exert slight pressure on the filtration process so that the liquid portion passes at a faster rate through the filter membrane.

How does GAC work? The surface of the Granular activated carbon (GAC) system, removes certain chemicals dissolved in water as they pass through it. The GAC absorbs the chemical due to its porous qualities. The absorption occurs on the internal surface of activated carbon. During absorption, liquids or gases pass through the porous structure of the activated carbon.

Maintenance.

contribute oxygen to the biological process

The solid residue is broken down aerobically 4 by the naturally occurring microbes. A continuous supply of oxygen helps to keep these microorganisms active and also reduces odors due to the denitrification process. The final step for the Membrane bioreactors is to pump the partially treated water for further disinfection to the Granular activated carbon chamber to remove traces of any organic matter and prevent the growth of pathogens.

filter with GAC can remove , organic contaminants, as well as chemicals that produce odors

Granular activated carbon (GAC) generally is an organic carbon filtration media made of materials that are high in carbon, such as coconut shells, coal, peat, and wood and it is used for water purification. A filter with GAC can remove certain unwanted contents from water, particularly organic contaminants, as well as chemicals that produce odors or tastes in water such as hydrogen sulfide or chlorine. Other chemicals, specifically iron and nitrate, cannot be removed with GAC. So, an initial removable of nitrates, iron, and other organic contaminants needs to take place before the water enters the GAC chamber or tube. (Systems using GAC,__) 3

Water further filtered through electrolysis to be used for for washing purposes

Pump treated water for further disinfection 1_Separation/ Sedimentation, #45. 2_Disinfection, #51. 3_Electrolysis, #62. 4_Aerobic Digestion, #53.

It is very important that the type and concentration of contaminants, and average water use, be known to determine the correct size and components of the system. The ability of the GAC to remove chemicals slowly decreases and it needs to be replaced. How often the GAC should be changed is a query that needs to be based on contaminant levels and water use. While some filters may last for several years if contaminant levels and/or water use are low, higher levels or use may require more frequent change-outs. (Maintenance of systems using GAC, 1 ).

1_Blue Diversion (using BAMBi), #81; Banka Bio-loo, #71. 2_Banka Bio-loo, #71; Biofilcom, #75; Biotoilet, #79; Blue Diversion, #81; Caltech PV Powered, #83. 3_Blue Diversion, #81.

1_Time/Maintenance and Obsolescence, #149

Off-grid Toilets

Elements and Processes

06 07

PLANT-BASED FILTRATION

Types

Vertical flow reed-bed - In this system, the effluent is periodically applied uniformly over the bed's surface using a network of pipes. The effluent percolates vertically down through the media and is collected by drainage pipes at the bottom, discharging to the next reed-bed in a series or directly into a watercourse or pond. The bed then remains empty of water until the next dose is applied. Vertical Flow Reed-beds are designed to be aerobic and to nitrify ammonia, converting it into nitrates and nitrites.

What is plant based filtration?

A reed-bed, also known as a constructed wetland, is a structure like a pond used to break down the organic matter in wastewater. This reed-bed contains gravels and sands, which are usually planted with either the common River Reed (Phragmites Australis) or Reed Mace (Typha Latifolia), otherwise known as Cattail in the USA. Contaminated effluent is applied either at one end or generally over the whole surface, depending on the type of reed-bed, and collected from the other end or by a series of drainage pipes at the bottom. (systems using Constructed Wetlands, 1 ) As the effluent passes through the gravels and sands, it comes into contact with the thin film of bacteria which grows naturally on the surfaces of the media particles. They are the primary agents breaking down the effluent's organic matter. These bacteria also grow around the root systems of the reeds, where the oxygen-rich atmosphere produced by the plants helps this process. Some systems need a plant-base filtration as part of their processes, which conditions their location and scalability (see Built Environment/Location, 1 and Time/Scalability, 2 ).

Typhas and Phragmites are the main species of plants used in constructed wetland, because of their widespread abundance, ability to grow at different water depths, ease transplantation, and broad tolerance of water composition (including pH, salinity, dissolved oxygen)

Vertical flow

Horizontal flow

Horizontal flow reed-bed - In this system the effluent is applied at one end and discharges from the other. These are generally low in oxygen and will de-nitrify the effluent converting the nitrogenous compounds into free nitrogen gas, which escapes to the atmosphere. The bed remains full of water at all times.

Life of reedbeds

How is reedbed working?

As the water flows through the different stages of the reedbed system the nutrients contained in the waste are converted by microbes and consumed by plants. This process means that pollutants and any harmful bacteria are reduced to safe levels (see Digestion, 1 ). The first reedbed is a very active ecosystem. It destroys bad bacteria and also converts ammonia into nitrate which is a much safer compound that plants and algae can use. Moving downstream, as the water arrives at the settling pond, naturally occurring bacteria take up the nitrates and release harmless nitrogen into the air, reducing the pollution in the water. Air mixes with the water as it splashes around the aerating flowforms and enters a stream. The water flows down stream to the second reedbed and then a wildlife pond. Here, a long standing time kills

Horizontal Flow Reed-beds will eventually block up and fail. The lifetime expectancy of these beds is between 5 and 15 years, depending on the strength and quality of the effluent being applied to them. Those receiving strong effluents with a high level of suspended solids will block up more rapidly. The media gets blocked easily and needs to be replaced entirely. Vertical Flow Reed-beds, if correctly sized, will last indefinitely. Blockages, when they occur, are generally confined to the top 25 mm of the surface sand layer, which can be easily removed and replaced. (see Time/Maintenance and Obsolescence, 3 )

Root hair Aerobic zone Facultative zone Vertical Flow Reedbed

Horizontal Flow Reedbed

Anaerobic zone

What is constructed wetlands/ treatment ponds?

A constructed wetland (CW) is an artificial wetland to treat sewage, greywater, stormwater runoff or industrial wastewater. Constructed wetlands are engineered systems that use the natural functions of vegetation, soil, and organisms to provide secondary treatment to wastewater. 1_Aerobic and Anaerobic Digestion, #53,54.

1_Solar Septic, #95; Bio-toilet, #79.

1_Built Environment/Location, #129. 2_Time/Scalability, #151. 3_Time/Maintenance and Obsolescence, #149.

Off-grid Toilets

Elements and Processes

DISINFECTION temperature (°C)

How does disinfection work? Feces contain a wide variety of pathogens from viruses, protozoa, and bacteria to helminths (worms) (see Human Solid Waste, 1 ). People can get sick or die from pathogens contained in human feces, but if treated properly, human waste is safe to handle, and it will greatly enhance crop production as well as soil quality (see Composting, 2 ). The most effective way to treat feces and make them safe to manage is by using ‘time and temperature’: the higher the temperature applied, the shorter the time required to destroy the pathogens (see Technology/Type, 3 ). Some systems use very high temperatures to assure pathogens disinfection in a short period of time (see Systems using high temperatures, 1 ).

VIRUS

Viruses cannot multiply outside of a host, but they can survive for several weeks. The lower the temperature, the longer the survival time for viruses while waiting for a new host; in right outdoor conditions and low temperature, viruses can survive for many years. They cannot survive temperatures above 55°C. Also, exposure to sunlight (ultraviolet rays) can destroy the virus within a couple of hours. Urine will not have viruses unless it has been contaminated with feces. (The line in the graphic refers to Enteric Viruses)

BACTERIA

Humans have a large number and types of bacteria in their intestines, and these leave the body along with feces. Bacteria that cause major health illnesses are E-coli, Salmonella, Shigella and Cholera.

E.Coli

These bacteria are very sensitive to the temperature and moisture content of their surroundings. In dry soil conditions, the number of E-coli drops by 99% while in saturated soil it will take three weeks to decrease their number by 90%. Hence water is a strong factor in the survival of E-coli. Temperature plays a significant role in eliminating this type of bacteria: 94 days at 4°C or 27 days at 37°C will cause elimination. At 60°C all E-coli die within a short period of time. (see ideal conditions of temperature and humidity per system, 1 )

SAFETY ZONE

70°

Salmonella

Heating solid waste, feces, at 65°C for a day will ensure that all living organisms are killed. Fluctuating temperature from hot to cold appears to stress the organism and causes a quicker die-off at lower temperatures. Other methods that can be used to kill pathogens include the use of chemicals like chlorine, but chemicals are expensive and must be used consistently and in correct proportions.

65° 60° 55° 50° 45° 40°

They are very hardy and can survive even after the sludge has dried for 85 days. The best way to eliminate Salmonella is to heat the feces for a day at temperatures over 60°C or store at a lower temperature for a longer period.

Shigella

These bacteria can survive for several months in clean water and moderate temperatures. However, they can be destroyed completely in less than 5 days if heated at temperatures of 60°C.

Cholera

At tropical temperatures, these bacteria can only live 2-4 days outside the host but if the temperature falls the survival time is extended up to three weeks say at 4°C. Cholera has a relatively low tolerance for heat, so it can be destroyed at 45°C if heated for about 5 days.

PROTOZOA

They can survive several months in moist soil and low temperature but are destroyed at temperatures of 60°C. (The line in the graphic refers to Entamoeba Hystolitica).

35° 30°

WORMS

25° 20°

time (h)

0.1

1 day

100

1 week

1000

1 month

10000

1 year

1_Human Solid Waste, #39. 2_Composting, #57.

Helminths (worms): Worms do not multiply in the host unless the host is infected with additional eggs or larvae to increase the worm population. Some kinds of common worms are: Hookworm can survive three to six weeks outdoors at moderate temperature. All its eggs in feces are destroyed at a temperature over 65°C. Flatworms, Tapeworms and Roundworms, all are destroyed at temperatures of 60°C. (The line in the graphic refers to Ascaris Lumbricoides) 1_Biochar, #73; Nano Membrane, #91; RTI International, #93.

1_Natural Environment/Climate, #137.

Off-grid Toilets

Elements and Processes

0808

0909

DIGESTION: DIGESTION:ANAEROBIC ANAEROBIC

DIGESTION: DIGESTION:AEROBIC AEROBIC

What Whatisisaerobic aerobicdigestion? digestion?

Aerobic Aerobic digestion digestion is the is the breakdown breakdown of of organic organic waste, waste, in the in the presence presence of of oxygen, oxygen, byby micro-organisms. micro-organisms.

1 1

What Whatisisanaerobic anaerobicdigestion? digestion?

Biomass Biomassdestruction destruction

How Howdoes doesaerobic aerobicdigestion digestionwork? work? 1 Initially 11 1Initially thethemicro-organisms micro-organismsdestroyed destroyedthethecomplex complex substances substances into into simple simple ones ones in in thethe presence presence of of oxygen oxygen to to produce produce carbon carbon dioxide, dioxide, water, water, and and ammonium ammonium bicarbonate. bicarbonate. This This ammonium ammonium bicarbonate bicarbonate increases increases thethe pHpH value, value, which which is is very very toxic toxic to to micro-organisms micro-organisms and and it also it also produces produces pungent pungent odors. odors.

22 22The The second second biological biological process process is nitrification is nitrification where where thethe nitrifying nitrifying bacteria bacteria convert convert ammonium ammonium bicarbonate bicarbonate with with thethe help help of of oxygen oxygen and and produce produce water, water, hydrogen hydrogen atoms atoms (acidic) (acidic) and and nitrates. nitrates. The The combination combination of of thethe byproducts byproducts from from thethe nitrification nitrification process process results results in in thethe formation formation of of nitric nitric acid, acid, creating creating a strong a strong acidic acidic condition condition that that cancan destroy destroy thethe nitrifying nitrifying microorganism. microorganism. 33 33 The The final final stage stage of of aerobic aerobic digestion digestion is is denitrification, denitrification,

which which is accomplished is accomplished in in absence absence of of oxygen. oxygen. At At this this stage, stage, denitrifying denitrifying bacteria bacteria convert convert nitrates nitrates to to nitrogen nitrogen gasgas and and ammonium ammoniumbicarbonate, bicarbonate,which whichagain againgoes goesinto intothethe nitrification, nitrification, thus thus making making thethe process process cyclic. cyclic. The The denitrification denitrification process process is is a very a very important important step step without without which which nitric nitric acid acid would would continue continue to to accumulate accumulate reducing reducing thethe alkaline alkaline environment. environment. Therefore, Therefore, thethe overall overall process process goes goes from from biomass biomass to to carbon carbon dioxide, dioxide, water, water, and and nitrogen nitrogen 1 )1 ) gas. gas. (Systems (Systems using using aerobic aerobic digestion digestion

The The aerobic aerobic process process cancan bebe operated operated under under mesophilic mesophilic (i.e.(i.e. ambient ambient temperatures) temperatures) and and thermophilic thermophilic (elevated (elevated temperatures, temperatures, normally normally 55−70°C) 55−70°C) conditions. conditions. (see (see comparative comparative Givoni Givoni chart chart forfor thethe Natural Natural Environment/ Environment/ Weather Weather 1 ).1 ). Temperature Temperatureis isclosely closelyconnected connectedto tothethedisinfection disinfection process process of of pathogens. pathogens. ( See ( See Disinfection Disinfection in in this this chapter chapter 1 ).1 ).

Polymers Polymers of of organic organic matter matter breaks breaks into into simple simple sugar, sugar, amino amino acid acid and and fatty fatty acid acid

Biomass Biomass breakdown breakdown byby micro-organisms, micro-organisms, in in presence presence of of Oxygen Oxygen

Hydrolysis Hydrolysis1

Polymers Polymers

Acidogenesis Acidogenesis2

Ammonium Ammonium bicarbonate bicarbonate

Water Water H 2O H 2O

Carbon Carbon dioxide dioxide

BYBY PRODUCTS PRODUCTS

COCO 2 2

Monomers Monomers

Nitrification Nitrification

Nitrates Nitrates Water WaterHydrogen Hydrogen + + H 2O H 2O

] HCO ] HCO [ NH [ NH 4 4

Denitrification Denitrification

3 3

+ +

H H

In absence In absence of of oxygen, oxygen, denitrifying denitrifying bacterias bacterias converts converts nitrates nitrates into into nitrogen nitrogen gasgas and and ammonium ammonium bicarbonate bicarbonate

Volatile Volatile Fatty Fatty Acid Acid

+ +

Fatty Fatty Acid Acid

H2SH2S

Acetogenesis Acetogenesis3 + +

Digested Digested

N ON3 O 3

+ +

Carbon CarbonAmmonia Ammonia Hydrogen Hydrogen Dioxide Dioxide NHNH Sulfide Sulfide Volatile Volatile 3 3 COCO 2 2

Ammonium Ammonium bicarbonate bicarbonate

Here Here Monomers Monomers areare broken broken further further into into CO2, CO2, NH3, NH3, H2S, H2S, volatile volatile fatty fatty acid acid and and other other byby products products

2 2

nitrifiying nitrifiying bacteria bacteria converts converts amonia amonia into into water water and and nitric nitric acid acid

How Howdoes doesaerobic aerobicdigestion digestionwork? work?

Monomers Monomers

pHpH

[ NH [ NH ] HCO ] HCO 4 4

+ +

Carbon Hydrogen Hydrogen Acetic Acetic acid acid Carbon dioxide dioxide H2H2 COCO 2 2

The The intermediate intermediate products products of of thethe preceding preceding stages stages areare converted converted into into methane, methane, carbon carbon dioxide, dioxide, and and water. water.

Methanogenesis Methanogenesis4 Nitrates Nitrates NONO 3 3

Ammonium Nitrogen Nitrogen Ammonium bicarbonate gasgas bicarbonate N 2N 2

[ N [N H 4 ]HCO H 4 ]HCO

The The intermediate intermediate products products of of thethe preceding preceding stages stages areare converted converted 2 2+ +3 3 into into methane, methane, carbon carbon dioxide, dioxide, and and water. water.

1_Disinfection 1_Disinfection #51. #51.

Carbon CarbonWater Water Methane Methane dioxide dioxide H O H O C HC H COCO 2 2

Anaerobic Anaerobic digestion digestion is the is the breakdown breakdown of of organic organic waste waste through through thethe action action of of living living organisms organisms that that dodo notnot require require oxygen. oxygen. The The four four keykey stages stagesof ofanaerobic anaerobicdigestion digestioninvolve involvehydrolysis, hydrolysis,acidogenesis, acidogenesis, acetogenesis acetogenesis and and methanogenesis. methanogenesis. Human Human waste waste is made is made upup of of bigbig molecules molecules (polymers) (polymers) and and forfor thethe bacteria bacteria in in anaerobic anaerobic digesters digesters to to access access thethe energy energy potential potential of of thethe material, material, these these large large organic organic units units need need to to bebe broken broken down down into into simple simple ones. ones.

1 Hydrolysis: 1 Hydrolysis: 1. 1. The The process process of of breaking breaking these these large large organic organic units units and and dissolving dissolving thethe smaller smaller molecules molecules into into a solution a solution is called is called hydrolysis. hydrolysis. The The products products from from this this stage stage areare simple simple sugars, sugars, amino amino acids, acids, and and fatty fatty acids. acids. 2 Acidogenesis: 2 Acidogenesis: 2. 2. At At this this stage, stage, thethe simple simple molecules molecules (monomers) (monomers) areare further further broken broken down down into into volatile volatile fatty fatty acids acids along along with with ammonia, ammonia, carbon carbon dioxide, dioxide, and and hydrogen hydrogen sulfide, sulfide, as as well well as as other other by-products. by-products. 3 3. 3Acetogenesis: 3. Acetogenesis: Some Some of of thethe simple simple molecules molecules produced produced in in thethe previous previousstage, stage,thethevolatile volatilefatty fattyacids acidsarearefurther furtherdigested digestedto to produce produce largely largely acetic acetic acid, acid, as as well well as as carbon carbon dioxide dioxide and and hydrogen. hydrogen.

4. 44. Methanogenesis: Methanogenesis: The The intermediate intermediate products products of of thethe preceding preceding 4 stages stages areare converted converted into into methane, methane, carbon carbon dioxide, dioxide, and and water. water. (Systems (Systems using using anaerobic anaerobic digestion digestion 2 )2 )

Anaerobic Anaerobicdigesters digesterscancanoperate operatein inone oneof ofthethethree threefollowing following temperature temperature conditions: conditions: Thermophylic, Thermophylic, which which involves involves break break down down of of organic organic matter matter byby organisms organisms that that cancan livelive at at high high temperatures temperatures of of 49–60°C 49–60°C Mesophylic, Mesophylic,which whichinvolves involvesbreak breakdown downof oforganic organicmatter matterbyby organisms organisms that that grow grow best best in in moderate moderate temperature, temperature, neither neither tootoo hothot nornor tootoo cold, cold, about about 35–41°C, 35–41°C, and and Psychrophylic, Psychrophylic, which which involves involves break break down down of of organic organic matter matter byby organisms organisms that that areare capable capable of of growth growth and and reproduction reproduction in in lowlow temperatures temperatures of of 16–24°C. 16–24°C. Higher Higher heat heat energy energy is required is required in in a thermophilic a thermophilic system system compared compared to to a mesophilic a mesophilic system, system, butbut thethe thermophilic thermophilic system system requires requires much much less less time time and and hashas a larger a larger gasgas output output capacity capacity and and higher higher methane methane gasgas content. content.

1_Biofilcom, 1_Biofilcom, #75; #75; Aerosan, Aerosan, #87; #87; Fresh Fresh Life,Life, #89, #89, andand Zero Zero Discharge, Discharge,#99. #99.2_Eco-san, 2_Eco-san,#87; #87;Solar SolarSeptic, Septic,#95; #95; Bio-toilet, Bio-toilet, #79; #79; Earth Earth Auger, Auger, #85; #85; Two-Pit Two-Pit Flush, Flush, #97; #97; Biogas Biogas Plant, Plant, #77; #77; Banka Banka Bio-Loo, Bio-Loo, #71. #71.

1_Natural 1_Natural Environment/ Environment/ Climate, Climate, #137. #137.

Off-grid Toilets

Elements and Processes

BIO-DIGESTERS

Aerobic Biodigester

Anaerobic Biodigester A biodigester is a tank where the organic material is stored, and the micro-organisms biologically digest it to release gas. This breakdown of organic matter can be done anaerobically (without oxygen--see Anaerobic digestion in this chapter 1 ) or aerobically (with oxygen--see Aerobic Digestion 2 ).

Solar Heater Solid Fertiliser

If the system uses anaerobic conditions for digestion, bacteria in the tank break down organic waste matter into a series of chemical elements through a chain of chemical reactions until methane (commonly known as biogas), carbon dioxide, and water are produced. The quantity of methane gas production depends on the volume of solid content. Therefore, if a group of bio-digester units are installed in proximity significant amount of biogas will be produced, which can be collected for cooking or heating purposes. (see Biogas Plant, 1 ).

In both cases, the solid waste is retained in the tank for digestion, a process that takes place for more than a year before desludging the tank safely. The outcome can be used as solid fertilizer.

CO2

The diagram on the left refers to systems that infiltrate the liquid waste into the ground and retain the solid for digestion (like the system Biofillcom, 4 ). An infiltration medium is provided in order to retain the solid parts before letting the liquids infiltrate into the ground. Coconut fibre and/or gravel layers are displayed for this purpose. The worms will be in charge of digesting the solid waste while the liquid travels into the ground, where naturally-contained bacteria proceed to decompose the waste anaerobically.

Digestion + Heat

Coconut Fibre

Digestion + Filtration

Gravel Gravel

Sedimentation

One or more parallel processes could facilitate the digestion of organic matter. For instance, in solar bio-digestors (such as the one applied in the Solar Septic system, 2 ), a solar heater feeds a coil inserted in the tank where hot water circulates. With this process, Disinfection starts to occur due to pathogens' vulnerability to high temperatures (see Disinfection in this chapter, 3 ). This process has been signalled with the number 1 in the diagram on the right. Other bio-digestors (see Bio-toilet, 3 ) have a filter medium to remove solid particles from the supernatant before being released into the constructed wetland for further plant-based treatment. This way, a higher proportion of solid waste is secured in the bio-digestor (procedure marked with the number 2 .

1 year

Other bio-digestors are based on aerobic decomposition (see Aerobic digestion, 2 ). Here, most of the solid waste is retained to be treated by organisms such as worms which have the capacity to digest the waste producing CO2 and water as byproducts (see comparison about systems' outputs, in Expense/Efficiency, 1 ).

Anaerobic digestion

It is important to consider here that the process of infiltration and the low-speed digestion provided by the ground are incompatible with toilets which require intense use conditions (comparative capacity and simultaneity of the systems mapped in chart Built Environment/Use, 2 ). If systems which use ground infiltration are stressed in their use over the ground's capacity to digest the infiltrated waste, land pollution may occur (see the comparative pollution chart for Natural Environment/Impact, 3 ).

H 2O

Methane

Ground Filtration

Constructed Wetlands 3 to 5 years

Anaerobic Digestion

Solid Fertiliser Treated Water

IFor both or the anaerobic bio-digestorssystems mentioned above, a constructed wetland is used for treating the liquid effluent. The wetland filters the liquid through the ground, retaining the solid particles, which are subject to aerobic and anaerobic decomposition in the ground and around plants' roots. (see Plant-based Filtration, 4 ).

1_Anaerobic Digestion #54. 2_Aerobic Digestion #53. 3_Disinfection #51. 4_Plant-based Filtration #49.

Pros and Cons The main advantage of aerobic digestion over anaerobic digestion is that it includes a reduced odor due to the non-production of hydrogen sulphide or methane and a better nutrient removal efficacy. The advantages of anaerobic treatment processes over aerobic treatment are the production of biogas which can be used as a source of renewable energy (natural gas/methane) and that it is less expensive as there is no need for oxygenation.

1_Biogas Plant, #77. 2_ Solar Septic, #95. 3_ Bio-toilet, #79. 4_ Biofilcom, #75.

1_Expense/ Efficiency #127. 2_Built Environment/ Use #133. 3_Natural Environment/ Impact #139.

Off-grid Toilets

Elements and Processes

COMPOSTING egg shells

Composting is a method of decomposing organic solid wastes by creating a compost pile, which is used to fertilize soil without the use of potentially harmful chemicals. The most important organisms in the breakdown process are bacteria present in the compost pile (see Anaerobic digestion, 1 ). The activity of these bacteria depends upon the raw material present, amount of air in a pile, moisture conditions of the pile, pile temperature and numerous other factors. Compostable organic materials normally contain a large number and many different types of bacteria, fungi, molds, and other living organisms. Throughout the process, these organisms may vary according to the temperature and users need to create the most favorable environment possible for the desired organisms. (System using Composting, 1 ).

fruit peels

kitchen scrap

garden waste

card -boards

Care must be taken, however, not to provide too much oxygen, which can dry out the pile and hinder the composting process. The standard value for moisture content is 50%–40% (or 20:1 to 40:1). (Conditions of temperature and humidity required per system in Natural Environment/Climate, 1 ).

shredded any large items into smaller pieces

5. Temperature:

moisture

Five main areas must be ‘controlled’ during composting:

1. Nutrient Balance:

14 days

Composting requires a proper balance of ‘green’ organic materials and ‘brown’ organic materials. ‘Green’ organic material includes grass clippings, food scraps, and manure, which contain large amounts of nitrogen. ‘Brown’ organic materials include dry leaves, wood chips, and branches, which contain large amounts of carbon but little nitrogen.

14 days

7 days

Vermicomposting:

It is the process by which worms are used to convert organic materials (usually wastes) into a humus-like material known as vermin-compost. (System using Worms or Maggots, 2 ).

CONSIDERATIONS: Worms are sensitive to changes in climate. Extreme temperatures and direct sunlight are not healthy for the worms. The best temperatures for vermicomposting range from 12°C to 25°C. In hot, arid areas, the bin should be placed under the shade

2. Particle Size:

Grinding, chipping, and shredding materials increases the surface area on which microorganisms can feed. Smaller particles produce a more homogeneous compost mixture and improve pile insulation to help maintain optimum temperatures. If the particles are too small, however, they might prevent air from flowing freely through the pile.

Microorganisms require a certain temperature range for optimal activity, which depends on the type of composting process. Certain temperatures promote rapid composting and destroy pathogens and weed seeds. Microbial activity can raise the temperature of the pile’s core to at least 60° C. If the temperature does not increase, anaerobic conditions occur.

95%

15%

moisture

3. Moisture Content:

Microorganisms living in a compost pile need enough moisture to survive. Water is the main element that helps to transport substances within the compost pile and makes the nutrients in organic material accessible to the microbes. Organic material contains some moisture in varying amounts, but moisture also might come in the form of rainfall or intentional watering. For a proper composting process, moisture level needs to be measured and maintained properly.

Aerated (Turned) Windrow Composting:

80%

moisture

40%

moisture

4. Oxygen Flow:

Aerated or turned windrow composting is suited for large volumes such as that generated by entire communities and collected by local governments. It will yield significant amounts of compost, which might require assistance to market the end product. Local governments may want to make the compost available to residents for a low or no cost. This type of composting involves forming organic waste into rows of long piles called ‘windrows’ and aerating them periodically by either manually or mechanically turning the piles. The ideal pile height is between four and eight feet with a width of 14 to 16 ft. This size pile is large enough to generate enough heat and maintain temperatures. It is small enough to allow oxygen to flow to the windrow's core.

CONSIDERATIONS: In a warm, arid climate, the pile needs to be covered or placed under a shelter to prevent water from evaporating. In rainy seasons, the shapes of the pile should be adjusted so that water runs off the top of the pile

Turning the pile, placing the pile on a series of piles, or including bulking agents such as wood chips and shredded newspaper all help aerate the pile. Aerating the pile allows decomposition to occur at a faster rate than in anaerobic conditions. 1_Anaerobic digestion, #54.

1_Biofilcom, #75; Biogas Plant, #77; Earth Auger, #85; Eco-san, #87; Fresh Life, #89; Two-pit Flush, #97; and Zero Discharge, #99. 2_Biofilcom, #75; Fresh Life, #89.

1_Natural Environment/ Climate, #137.

Off-grid Toilets

Elements and Processes

ENERGY e-

Some of the off-grid systems compiled in this book, need electric energy to power some of their mechanisms and processes such as electrolysis or combustion ( 1 ). These are some of the devices used for this purpouse. (See electric need of the systems in Expense/Efficiency, 1 ).

These are the steps of the process:

Hydrogen (fuel)

1 When the external heat source is activated, the heat a) energy starts transforming from the heat source to the hot end of the cylinder. 2 This heat transfer increases the gas molecules b) temperature trapped in the cylinder’s hot end. As the temperature rises, the gas start to expand inside the cylinder. (c) 3 The gas expansion increases the pressure on the displacer piston surface, pushes the piston away. (d) 4 The displacer piston’s movement causes a gas exchange from the hot end to the cold end and the cold end to the hot end of the cylinder. This way the process repeats.

This displacer piston is coupled with a flywheel. The main objective of this connecting rod is to receive reciprocating motion by the piston and delivers it to the cycle. As the cycle gets motion by the connecting rod, it transforms this motion into rotary motion and rotates the flywheel. This way heat energy is converted to mechanical energy. If a generator is connected to the flywheel, the rotation of the flywheel will generate electricity. Stirling engines are unsuitable for applications that need to change power output levels quickly. It is used by some off-grid toilets for converting heat into mechanic movement or to generate electricity to feed back the system. (System using Stirling engines, 1 ).

Crank shaft 1 Heating (a)

Cold air

(-)

H H

(b) 2 Expansion (+)

Water (H2O)

Heat from coil expanding gas molecules and move the piston

Oxygen (air)

HYDROGEN FUEL CELL: A fuel cell is an electrochemical energy conversion device that uses elements like hydrogen and oxygen to generate electricity, producing heat and water as by-products. Hydrogen atoms from hydrogen gas enters the negative side of the cell (anode) where electrons are taken out of their atoms. The remaining part (positively charged hydrogen ion) pass through the membrane to the negative part of the cell (cathode). The electrons flow through the circuit to generate electricity. After passing through the circuit, the electrons combine with the hydrogen ion and oxygens from the air to generate the fuel cell's by-products: water and heat. (Systems using Hydrogen Fuel Cell, 2 ).

PHOTOVOLTAIC PANEL: Sunlight is composed of photons, which contain varying amounts of energy. Photovoltaic panels convert light energy (photons) into electricity using semiconducting materials, which exhibit the photovoltaic effect. Photovoltaic Panels are more profitable in places with high solar thermal energy. (see Natural Environment/Climate, 2 ). When a photon hits a photovoltaic (PV) device, energy is transferred from the photon to the electrons in the material. These free electrons, each carrying a negative charge, begin to flow towards the negative terminal of the cell, creating an imbalance of electrical charge between the cell's positive and negative terminals. This imbalance, in turn, creates a voltage difference like a battery's negative and positive terminals. Electricity starts to flow when this electrical circuit is connected to an external load, such as a battery. (Systems using Photovoltaic Panels, 3 ).

(d) 4 Compression

STIRLING ENGINE: A Stirling engine is a heat engine that is operated by the cyclic compression and expansion of air or other gas between different temperatures, resulting in a net conversion of heat energy to mechanical work. In the off-grid toilets analised in this book, Stirling engine is used for converting heat energy to electrical energy.

The fly wheel rotation can start generators to provide electricity

1_Conversion/ Electrolysis and Combustion #61,62.

1_Biochar, #73; RTI International, #93. 2_Caltech PV Powered, #83. 3_Blue Diversion, #81; Caltech PV Powered, #83; Solar Septic, #95.

1_Expense/ Efficiency, #127. Climate, #137.

2_Natural Environment/

Off-grid Toilets

Elements and Processes

1313

1414

ELECTROLYSIS ELECTROLYSIS

CONVERSION CONVERSION

CONDENSATION: CONDENSATION:

What What is is a hydrophilic a hydrophilic surface? surface?

Sometimes Sometimes water water spreads spreads evenly evenly when when it hits it hits a surface; a surface; sometimes sometimes it it beads beads into into tiny tiny droplets. droplets. Human Human beings beings have have noticed noticed these these differences differences since since ancient ancient times; times; a better a better understanding understanding of of these these properties, properties, and and new new ways ways of of controlling controlling them, them, may may bring bring important important new new applications. applications. Materials Materials with with a special a special affinity affinity forfor water water —those —those it spreads it spreads across, across, maximizing maximizing contact— contact— areare known known as as hydrophilic. hydrophilic. Those Those that that naturally naturally repel repel water, water, causing causing droplets droplets to to form, form, areare known known as as hydrophobic. hydrophobic. If the If the droplet droplet spreads, spreads, wetting wetting a large a large area area of of a surface, a surface, then then such such a surface a surface is is considered considered hydrophilic, hydrophilic, or or a a water-loving water-loving surface. surface. System System that that requires requires water water vapor vapor to to convert convert to to liquid liquid form form cancan useuse a hydrophilic a hydrophilic surface surface as as it attracts it attracts more more water water particles particles and and thethe accumulation accumulation of of water water particles particles onon thethe surface surface makes makes it easier it easier forfor them them to to bebe converted converted into into tiny tiny water water 1 ).1 ). droplets. droplets. (see (see Nano Nano Membrane Membrane in in Systems, Systems,

What What is is Electrolysis? Electrolysis?

‘Electrolysis’ ‘Electrolysis’ literally literally means means thethe breakdown breakdown of of substances substances byby using using electricity. electricity. The The process process occurs occurs in in a liquid a liquid solution solution (electrolyte) (electrolyte) that that gives gives a possibility a possibility to to transfer transfer thethe electrically electrically charged charged particles particles (ions) (ions) between between two two electrodes electrodes (a (a conductor conductor through through which which electricity electricity cancan flow). flow). When When anan electrical electrical current current is applied, is applied, thethe positive-charged positive-charged ions ions (cations) (cations) move move to to thethe cathode cathode (negatively-charged (negatively-charged electrode) electrode) while whilethethenegative-charged negative-chargedions ions(anions) (anions)move moveto tothetheanode anode (positively-charged (positively-charged electrode). electrode). At At thethe cathode cathode oxygen oxygen is removed is removed from from thethe molecules molecules (process (process known known as as reduction) reduction) as as thethe cations cations areare reduced reduced (removal (removal of of oxygen oxygen from from a molecule) a molecule) and and at at thethe anode anode oxygen oxygen is added is added to to thethe molecules molecules (process (process known known as as oxidation). oxidation). Electrochemical Electrochemical treatment treatment systems systems ( 1(),1 employ ), employ thethe process process of of electrolysis electrolysis to to remove remove thethe unwanted unwanted dissolved dissolved toxic toxic chemicals chemicals and and microorganisms microorganisms from from wastewater. wastewater. These These systems systems ( 4( ),4 may ), may need need photovoltaic photovoltaic panels panels forfor producing producing energy energy (see (see suitable suitable locations locations in in 2 and 2 ), Natural Natural Environment/Climate, Environment/Climate, ), and storage storage through through batteries batteries (both (bothcomponents componentscontaining containinga ahigh highcarbon carbonfootprint--see footprint--see 3 ).3 ). Natural Natural Environment/Impact, Environment/Impact,

Waste Waste water water

(+) (+)

High High temperature temperature converting converting water water to to vapor vapor Vapor Vapor particles particles Particles Particles attracted attracted to to hydrophilic hydrophilic beads beads creating creating water water droplets droplets

Disinfecting Disinfecting water water using using table table salt salt (NaCl) (NaCl) Hyrdophobic Hyrdophobic

Hyrdophilic Hyrdophilic

COMBUSTION: COMBUSTION:

Carbonization Carbonization is the is the degradation degradation of of carbonaceous carbonaceous material material such such as as human human waste, waste, or or other other organic organic household household waste waste in in thethe absence absence of of oxygen. oxygen. In In thethe carbonizer, carbonizer, thethe materials materials areare treated treated using using a slow a slow 2 ).2 ). pyrolysis pyrolysis method. method. (Systems (Systems using using Carbonization, Carbonization, Pyrolysis Pyrolysis is the is the heating heating of of organic organic material, material, such such as as biomass, biomass, in the in the absence absence of of oxygen. oxygen. Usually, Usually, thethe temperature temperature reached, reached, is between is between 300°C 300°C to to 500°C. 500°C. Pyrolysis Pyrolysis products products always always produce produce solid solid biochar biochar and andnon-condensable non-condensablegases gasessuch suchas:as:hydrogen hydrogengas, gas,carbon carbon monoxide, monoxide, methane, methane, ethyne, ethyne, and and ethene ethene (gases (gases which which cancan bebe used used to to generate generate electricity). electricity). This This method method of of converting converting human human waste waste to to some some useful useful products products is is one one of of thethe most most favorable favorable and and effective effective 3 ).3 ). mechanisms, mechanisms, which which is environmentally is environmentally friendly. friendly. (See (See BioBio Char, Char,

Electrolyzed Electrolyzed water water is produced is produced byby thethe electrolysis electrolysis of of ordinary ordinary taptap water water containing containing dissolved dissolved saltsalt (sodium (sodium chloride) chloride) to to produce produce a a solution solutionof ofhypochlorous hypochlorousacid acid(HOCI) (HOCI)which whichhashasdisinfectant disinfectant 5 ).5 ). properties. properties. (See (See Caltech Caltech PVPV Powered Powered in in Systems, Systems,

Hydrophilic Hydrophilic beads beads Heat Heatis aisbasic a basic principle principle forfor disinfection, disinfection, thethe higher higher thethe temperature, temperature, 1 ).1Bringing thethe shorter shorter thethe time time needed needed (see (see Disinfection, Disinfection, ). Bringing sludge sludge upup to to thethe right right temperature temperature (180~200 (180~200 °C)°C) forfor 30~60 30~60 minutes minutes results results in an in an irreversible irreversible change change to to its its organic organic matter. matter.

How How does does it it work? work?

Pathogens Pathogens have have charges, charges, much much likelike magnets. magnets. Hypochlorous Hypochlorous acid acid (HOCl) (HOCl) hashas a neutral a neutral charge charge enabling enabling it to it to attach attach to to germ germ surfaces surfaces which which carry carry a negative a negative electrical electrical charge. charge. Electrons Electrons areare removed removed through through thethe combination combination with with oxygen oxygen (oxidation) (oxidation) which which disrupts disrupts thethe cellular cellular structure structure of of pathogens pathogens byby destroying destroying thethe cellcell walls walls of of bacteria bacteria and and protein protein coats coats of of viruses. viruses. The The lowlow molecular molecular weight weight of of thethe disinfectant disinfectant solution solution makes makes it effective it effective enough enough to to penetrate penetrate thethe cellcell walls walls and and protein protein coats coats allowing allowing it to it to react react faster faster and and destroy destroy thetheDNA DNAand andRNA RNAinside insideof ofbacteria bacteriaand andviruses, viruses,thereby thereby inactivating inactivating them. them. Electrolyzed Electrolyzed water water also also hashas nono adverse adverse impact impact onon thethe environment. environment. Because Because it leaves it leaves nono toxic toxic residue, residue, it can it can bebe used used to to wash wash fresh fresh foods, foods, without without affecting affecting taste taste and and quality. quality.

Excess Excessfuel fuelin inthethecombustion combustionchamber chamberduring duringcombustion combustion characterizes characterizes a rich-burn a rich-burn engine, engine, while while excess excess airair in in thethe combustion combustion chamber chamber characterizes characterizes a lean-burn a lean-burn engine. engine. 1_Disinfection, 1_Disinfection, #51. #51.

1_Nano 1_NanoMembrane, Membrane,#91. #91. 2_Biochar, 2_Biochar,#73; #73;Nano Nano Membrane, Membrane, #91; #91; RTIRTI International, International, #93. #93. 3_Biochar, 3_Biochar, #73. #73. 4_Blue 4_Blue Diversion, Diversion, #81; #81; Caltech Caltech PV PV Powered, Powered, #83; #83; RTIRTI International, International, #93. #93. 5_Caltech 5_Caltech PV PV Powered, Powered, #83. #83.

1_Technology/ 1_Technology/Type, Type,#143. #143.2_Natural 2_NaturalEnvironment/ Environment/ Climate, Climate, #137. #137. 3_Natural 3_Natural Environment/ Environment/ Impact, Impact, #139. #139.

Off-grid Toilets

Elements and Processes

CIRCULAR ECONOMY

The Circular Economy (CE) of sanitation focuses on the whole sanitation chain, which includes the provision of toilets, waste collection, treatment and transformation into sanitation-derived products, including fertilizer, fuel, and clean water. Then selling this fertilizer to farmers who will use them for agriculture and generate more incomes.

Compost use

Sale to farmer

Treated water

Basic Model

Collection and transport

Compost Treatment and processing

The main factors determining the value sanitation are: 1) The volume of waste collected, 2) Integration of fecal sludge (FS) with other waste streams, 3) Enabling policies and subsidies, and 4) Marketing

Volume of waste collected

Mixing of sludge with other waste

BLUE DIVERSION TOILET 1 : ENTREPENEUR LOOP 1. 1 Entrepreneurs buy a few sets of toilets from a franchisor. 2. Entrepreneurs pay users to install the toilet. 2 3. User implements the toilet. 3 4. Solid and liquid waste are collected in two separate 4 containers. 5 Employment opportunity is created within the commu5. nity to transfer waste from the user to the treatment plant. 6 6. Waste collection team collect the containers and transfer them to the treatment plant. 7 7. In the treatment plant, waste is converted to fertilizer. 8. Fertilizers are sold to farmers or other agricultural 8 companies, generating more income for entrepreneurs.

Pay

3 1

1 Entrepreneur 8 6

Construct

User 6

Policies

1 The user builds a toilet by taking a loan from the franchi1. sor. 2 Franchisor helps to install the toilet. 2. 3 3. Solid and liquid waste are collected in two separate containers. 4 4. The user follows a self-composting process to convert waste to fertilizer. 5 5. Fertilizers obtained by self-composting can be sold to local farmers, and the user can use them for agricultural purposes. 6 6. Selling or using the fertilizer generates more earnings for the user. 7 7. The user can repay the loan taken from the franchisor from the earnings obtained by selling or using the fertilizer

Loan

Some technical, social, and political transformations would need to take place to make circular economy for sanitation a business that could drive the sanitation service chain. Technically, businesses often struggle to collect sufficient waste to make the concept of reuse feasible. If the treatment plant operates below its designed capacity, it consumes all the electricity produced from the biogas and does not export any to the grid, and consequently it is difficult to achieve a circular economy.

1. Sanergy installed the toilet for the user. 2 2. Solid and liquid waste are collected in two separate containers. 3. Waste collection team collect the containers and 3 transfer them to the treatment plant. 4 4. The treatment plant converts waste to fertilizer using aerobic digestion. 5 5. Fertilizer and animal food is obtained from this system. 6. Fertilizers can be sold, and the sanergy company earns 6 more money. 7 7. A percentage of the earnings is given to the users for using the fresh life toilet.

Technical

Waste collection

Waste management

Social

Marketing

Product awareness

Political

Government policy

Certification of products

1 Self-composting

Self-farming 5

Capacity of treatment plant

4 5 Economy

Pay

Fertilizer

Animal Food 5

Jobs

Transport 6

Marketing

Franchisor

FRESH LIFE TOILET 2 LOOP Subsidies

Along with marketing from the selling organizations, people's resistance to products can also be overcome with assistance from government policy. Political recognition and certification of products can act as a driver of circular economy business viability here.

Transport 3

BLUE DIVERSION TOILET 1 : USER LOOP

Electricity

The Circular Economy Sanitation Model

So, to overcome these issues, an organization can follow container-based sanitation where they are the ones controlling the waste collection process and don't need to encourage people to bring waste to their treatment site. A considerable improvement in financial viability can be achieved by expanding the collection system of fecal sludge. Another difficulty has been that the solid waste received contains plastics that require a lot of time and effort to sort. This was particularly true for fecal sludge treatment plants that rely on desludging trucks bringing sludge to the site. So, proper waste management policies based on the identified gaps and issues of waste collection, integration of other waste streams, and subsidies will play a vital role here.

Since the 1930s, chemical fertilizers have helped farmers in increasing crop production. While chemical fertilizers have their place in increasing plant nutrients in adverse weather conditions or when plants need additional nutrients, there are also many harmful effects of chemical fertilizers. Some of the toxic chemical fertilizers may cause waterway pollution, increased air pollution, and acidification and mineral depletion of the soil. Production of chemical fertilizer also contributes to carbon footprint. Circular sanitation models are implemented in few cities of India such as, Devanahalli, Dharwad, Hyderabad, Nasik, and Puducherry. The reuse of feces as fertilizer has also been common in Japan. Therefore, on local and national level people at many places in the world use human waste as fertilizer but unfortunately at a global level, the use of human-waste derived compost is not recognized by Global Good Agricultural Practices, one of the main farming standards.

Fertilizer Air pollution

Blue Diversion toilet 1 circular economy loop Fresh life toilet 2 circular economy loop

{

Entrepreneur loop User loop

Waterway pollution

Some users work as service provider employees.

7 Treatment plant

1_Composting, #57.

More crop production

Drawbacks

Benefits

For System’s Outputs see Efficiency Chart 1

Contributes more carbon footprint

1_Blue Diversion, #81. 2_Fresh Life #89.

Acidification and mineral depletion of the soil

Plant nutrients in adverse weather conditions

1_Expense/ Efficiency, #127.

Off-grid Toilets

Elements and Processes

ENDNOTES 01. HUMAN SOLID WASTE Rose C, Parker A, Jefferson B, Cartmell E. "The Characterization of Feces and Urine: A Review of the. Critical Reviews in Environmental Science and Technology. September 2015. https://dspace.lib.cranfield.ac.uk/bitstream/handle/1826/9736/The_characterization_of_ feces%20and%20_urine-2015.pdf;jsessionid=909F33BB675C209A29E37A04CFE9B405?sequence=1 Rowan, Karen."'Poop Transplants' May Combat Bacterial Infections"20 Oct. 2012,https://news.yahoo.com/poop-transplants-may-combat-bacterial-infections-130609662.html

02. HUMAN LIQUID WASTE

Pradhikaran, Maharashtra Jeevan. "SANITATION AND LIQUID WASTE MANAGEMENT Training Module for Local Water and Sanitation Management" CEPT University, 2012, https://pas.org.in/Portal/document/ResourcesFiles/pdfs/Module_3%20Sanitation%20and%20 liquid%20waste%20management.pdf

03. DIVERSION

September 07, 2022. http://www.amtaorg.com/Membrane_Bioreactors_for_Wastewater_Treatment.html Beat, Stauffer and Dorothee Spuhler. “Membrane Bioreactor.” SSWM. Accessed September 07, 2022. https://sswm.info/water-nutrient-cycle/wastewater-treatment/hardwares/semi-centralised-wastewater-treatments/membrane-bioreactor#:~:text=Membrane%20Bioreactors%20combine%20conventional%20 biological,advanced%20level%20of%20nutrient%20removal Everblue. “Membrane Biological Reactor MBR || MBR Technology || MBR Filtration System ||Membrane BioReactor.” February 01, 2019. Video, 4:13. https://www.youtube.com/watch?v=qaoM3-xWNjI&ab_ channel=Everblue Minnesota Department of Health. “Water Treatment Using Carbon Filters: GAC Filter Information.” Accessed September 07, 2022. https://www.health.state.mn.us/communities/environment/hazardous/topics/gac.html#types Tuser, Cristina. “What is Granular Activated Carbon (GAC)?.” WWD. January 04, 2022. https://www.wwdmag.com/editorial-topical/ what-is-articles/article/10939799/what-is-granular-activated-carbon-gac

06. PLANT BASED FILTRATION Arm Reedbeds. “Construction Wetlands.” Accessed August 20, 2022. https://armreedbeds.co.uk/constructed-wetlands/

Judd, Simon. “Sludge treatment − an overview of aerobic digestion.” Sludge Processing. May 08, 2020. https://www.sludgeprocessing. com/aerobic-digestion/aerobic-digestion/ Madhusha. “Difference Between Nitrification and Denitrification.” Pediaa. December 15, 2017. https://pediaa.com/difference-between-nitrification-and-denitrification/ Ovivo®. “Aerobic Digestion: Learning the chemistry behind the Aerobic Digestion process.” February 08, 2016. Video, 4:57. https:// www.youtube.com/watch?v=mGYMxzusI0w&ab_channel=Ovivo%C2%AE

09. ANAEROBIC DIGESTION Wikipedia. 2022. “Acidogenesis.” Wikimedia Foundation. Last modified August 18, 2022. 01:40. https://en.wikipedia.org/wiki/Acidogenesis Wikipedia. 2022. “Anaerobic digestion.” Wikimedia Foundation. Last modified July 13, 2022, 16:10. https://en.wikipedia.org/wiki/Anaerobic_digestion

AOS Treatment Solutions. “What Is Sedimentation in Water Treatment?.” May 01, 2018. https://aosts.com/what-is-sedimentation-inwater-treatment-types-settling-tanks/ Lakeside Equipment Corporation. “What is an Archimedes Screw Pump?.” July 28, 2020. https://www.lakeside-equipment.com/whatis-an-archimedes-screw-pump/

Reedbeds. “What is a reed-bed or a constructed wetland?.” Accessed August 20, 2022. https://www.reedbeds.co.uk/page/what-isa-reed-bed-or-a-constructed-wetland.php

Aggie Horticulture. “Chapter 1, The Decomposition Process.” Accessed September 07, 2022. https://aggie-horticulture.tamu. edu/earthkind/landscape/dont-bag-it/chapter-1-the-decomposition-process/#:~:text=The%20process%20of%20decomposition%20 %E2%80%94%20the,matter%20to%20change%20into%20compost

Purdue University. “Collection of Gas Over Water.” Accessed September 07, 2022. https://chemed.chem.purdue.edu/genchem/lab/ techniques/gascollect.html

V. Halverson, Nancy. “Review of Constructed Subsurface Flow vs. Surface Flow Wetlands.” Aiken: Westinghouse Savannah River Company, 2004. https://digital.library.unt.edu/ark:/67531/ metadc782197/m2/1/high_res_d/835229.pdf

05. FILTRATION AMTA. “Membrane Bioreactors for Wastewater Treatment.” Accessed

08. AEROBIC DIGESTION

HZO. “Hydrophilic vs. Hydrophobic – What’s the Difference?.” Accessed August 20, 2022. https://www.hzo.com/blog/hydrophilic-hydrophobic-waterblock-technology-whats-difference/ StudentLesson. “Difference between lean burn and rich burn engine.” April 11, 2022. https://studentlesson.com/difference-between-lean-burn-and-rich-burn-engine/ Wikipedia. 2022. “Carbonization.” Wikimedia Foundation. Last modified July 12, 2022. 02:58. https://en.wikipedia.org/wiki/Carbonization

Canada Agriculture and Food Museum. “Electrolysed Water.” December 17, 2016. Video, 1:55. https://www.youtube.com/watch? v=0mkWNwlp2CY&ab_channel=CanadaAgricultureandFoodMuseum

Pullen, Tim. “Reed Beds: How do They Work for Waste Water Management?.” Housebuilding & Renovating. October 18, 2021. https:// www.homebuilding.co.uk/advice/reed-beds

Knos, Tore, A Sh*tty Little Book: Urine Diverting Dehydrating Toilet, Safe Sewage Best Fertilizer, 2018. Createspace Independent Publishing Platform, UK.

Chandler, David L. “Explained: Hydrophobic and hydrophilic.” MIT News. July 16, 2013. https://news.mit.edu/2013/hydrophobic-and-hydrophilic-explained-0716

“How Does a Biodigester Septic Tank Work: All You Need to Know.” Organica Biotech, 10 June 2021, organicabiotech.com/how-does-abiodigester-septic-tank-work-all-you-need-to-know.

04. SEPARATION

07. DISINFECTION

13. CONVERSION

14. ELECTROLYSIS

margo.M. “All You Need to Know About Biodigester Septic Tanks HomeBiogas.” HomeBiogas, 31 Mar. 2022, www.homebiogas.com/ blog/all-you-need-to-know-about-biodgester-septic-tanks.

Welen, Anders. "User's Manual Aquatron separator Installation and Maintenance" Aquatron International AB, October 201.https:// envirocompostingtoilets.co.nz/wp-content/uploads/2019/03/Aquatron_User_Manual.pdf

Wikipedia. 2022. “Stirling engine.” Wikimedia Foundation. Last modified May 14, 2022. https://en.wikipedia.org/wiki/Stirling_engine

10. BIODIGESTER

Centre for Science and Environment. “Constructed Wetlands Wastewater Treatment Systems.” Accessed August 20, 2022. https:// www.cseindia.org/constructed-wetlands-wastewater-treatment-systems-6215#:~:text=Through%20the%20process%20of%20water,removing%20them%20from%20the%20water

Wikipedia. 2022. “Urine-diverting dry toilet.” Wikimedia Foundation. Last modified August 02, 2022. 19:30. https://en.wikipedia.org/wiki/ Urine-diverting_dry_toilet

Engineer Waqar. “What Is A Crankshaft? | How does a Crankshaft Work?.” Mechanical Boost. Accessed August 20, 2022. https://mechanicalboost.com/crankshaft/

11. COMPOSTING

EPA. “Types of Composting and Understanding the Process.” April 21, 2022. https://www.epa.gov/sustainable-management-food/ types-composting-and-understanding-process

12. ENERGY Alkhalid, Mohammed. “Stirling Heat Engine and Peltier Devices.” Suffolk University. October 31, 2014. https://sites.suffolk.edu/ malkhaldi/2014/10/31/stirling-heat-engine-and-peltier-devices/ Engineer Waqar. “Stirling Engine | How does a Stirling Engine work?.” Mechanical Boost. Accessed August 20, 2022. https://mechanicalboost.com/stirling-engine/

Chopra, A. K., Arun Kumar Sharma and Vinod Kumar. “Overview of Electrolytic treatment: An alternative technology for purification of wastewater.” Archives of Applied Science Research 3, no. 5 (January): 191-206. https://www.scholarsresearchlibrary.com/articles/overview-of-electrolytic-treatment-an-alternative-technology-forpurification-of-wastewater.pdf Wikipedia. 2022. “Electrolysis.” Wikimedia Foundation. Last modified. August 04, 2022. https://en.wikipedia.org/wiki/Electrolysis ·Hughess Safety. “What is Electrolysed Water?.” July 14, 2020. https://www.hughes-safety.com/gb/hub/electrolysed-water/

15. CIRCULAR ECONOMY Hunt, Janet. “Harmful Effects of Chemical Fertilizers.” Hunker. Accessed August 20, 2022. https://www.hunker.com/12401292/harmful-effects-of-chemical-fertilizers Mallory, Adrian, Daniel Akrofi, Jenica Dizon, Sourav Mohanty, Alison Parker, Dolores Rey Vicario, Sharada Prasad, Indunee Welivita, Tim Brewer, Sneha Mekala, Dilshaad Bundhoo, Kenny Lynch, Prajna Mishra, Simon Willcock and Paul HutchiWngs. “Evaluating the circular economy for sanitation: Findings from a multi-case approach.” Science of The Total Environment 744, (November 2020). https://doi. org/10.1016/j.scitotenv.2020.140871

Off-grid toilet systems 01

01 05

05 09

09 13

Aerosan

Aerosan Biogas plant

Biogas plant Earth auger

Earth auger RTI International 13

02 06

06 10

10 14

Banka bioloo

Banka bioloo Bio-toilet

Bio-toilet Eco-san

Eco-san Solar septic

01 05

Biochar by Pyrolysis 03 04 07 08

Biofilcom

05 09

Aerosan

Aerosan Biogas plant

Biochar by Pyrolysis Biofilcom Biogas plant Blue diversion Earth auger Caltech pv-powered 08 09 12 13

07 11

11 15

Blue diversion Fresh-life

Fresh-life Two-pit flush

Caltech pv-powered Earth auger Nano membrane RTI International 12 13 16

Nano membrane Zero discharge

RTI International

02 06

06 10

10 14

Banka bioloo

Banka bioloo Bio-toilet

Bio-toilet Eco-san

Eco-san Solar septic

Solar septic

Biochar by Pyrolysis 03 04 07 08

Biofilcom

Biochar by Pyrolysis Biofilcom Blue diversion Caltech pv-powered 08 12

07 11

11 15

Blue diversion Fresh-life

Fresh-life Two-pit flush

Two-pit flush

Caltech pv-powered Nano membrane 12 16

Nano membrane Zero discharge

Zero discharge

This chapter compiles sixteen off-grid sanitation systems which have been implemented worldwide. The systems are explained in a comprehensive manner through information provided directly by the developers of the systems. Despite the effort to clarify all steps involved in the selected systems, some information gaps are still noticeable due to the confidentiality related to some patent rights involved.

Off-grid Toilets

Off-grid Toilet Systems

AEROSAN Biological

This Low-Cost Sanitation for emergencies was developed by Aerosan in 2012 and was implemented in Nepal and Haiti. This system uses a biological process, aerobic digestion, to break down human waste. This is a four-toilet cluster with a large vent pipe in the center connected to each toilet unit. Due to the use of re-purposed vinyl billboard fabric and the central vent pipe, a Venturi effect enables air to flow and reduces by drying the volume accumulation of excreta, which is followed by a further composting process. Initially, as input, this system requires a layer of coconut fiber. This sanitation system is encouraged for use in sunny and windy climatic conditions as passive solar heating and ventilation aid drying. Work Process:

Roof covering Wooden structure

$ 0.25 k

10-20

(Per Toilet)

Vinyl billboard fabric Waterproof Cleanable surfaces Allows air to flow easily

Structure

Mesh fabric to ventilate odor out

Aerosan has developed a four-toilet array and a separate single-unit cubicle.

Vinyl billboard fabric

Toilet base Squat pan

Module

Raised surface Protects from flood

2 Ventilation: Key to the design is the use of enhanced passive ventilation which draws more air than is necessary for both control of odors and also drying of excreta. a. Material: Re-purposed vinyl billboard fabric. This billboard fabric makes a good barrier against UV radiation and weather in general. It also allows it to be pulled very tightly around the frames making up the cubicle, such that the resulting walls were taut and didn’t blow around in the wind. The holes in the fabric provide air to circulate to move more air through the system than would typically be available in a typical 4” (100 mm) vent pipe.

(50C)

(+) Human waste

Drying agent ( Coconut fiber)

Easy to construct

b. Outlet: The outlet of ventilation chimney is 15’ (4.3 m) above the ground, so odors are released at a higher elevation than typical vented toilet cubicles. Through the improved ventilation, a degree of drying takes place which reduces volume accumulation of excreta and thus increases the number of users that can use the system per maintenance period.

Low cost

Sun

Wind

Treated Waste

Suitable for emergency response

Health and Acceptance -Aerosan toilets provide a hygienic toilet environment through the provision of a large vent pipe resulting in reduced occurrence of flies and mosquitos (the entire vent pipe is covered with fabric). -As these toilets are dry systems, currently, they do not have provision for water-based anal cleansing; hence acceptance in India will have to be assessed before application. -This system is ideal for humanitarian and development applications during emergencies and in water stressed areas.

3 Composting: After certain period, when the collection bin gets full, the waste can be transferred to a treatment plant, or it can go through aerobic decomposition 1_ /composting process 2 . (Other systems using aerobic digestion, 1 ) Pros:

-The Vinyl might tear due to operational abuse or windy conditions. Adequate repairs must be carried out as and when required. -Degraded faecal matter has to be removed from the containment structure below the toilet pan as and when it gets filled. -Applying ash or sand on the pan after every use is advised to prevent stink 2 .

1 No Diversion: Urine and feces fall directly into a collection bin.

Operations and Maintenance Requirement 1

3 Advantage

- Drying leads to a lower faecal sludge accumulation rate, increasing the desludging period. - In areas with high-water table and the problem of flooding, this design is important because all excreta are contained in a waterproof container.

Sun helps to evaporate the liquid waste fast

Suitable for flood-prone region

Also functions in monsoon

Can withstand heavy winds.

With suitable compost cover material, this system will produce 80g/user/day of fertilizer 3 . This will enrich the soil, helping retain moisture and suppress plant diseases and pests. Reduces the need for chemical fertilizers. Encourages the production of beneficial bacteria and fungi that break down organic matter to create humus, a rich nutrient-filled material.

Cons: - Appropriate care must be taken during the rainy season to prevent water from entering the containment system through the vent pipe. - Low-height vent pipes can lead to the presence of mosquitoes and flies.

1_Aerobic Digestion, #53. 2_Composting, #57.

1_Biofilcom, #75; Fresh Life, #89; Zero Discharge, #99.

1_Technology/ Level, #145. 2_Natural Environment/ Impact, #139. 3_Expense/ Efficiency, #127.

Off-grid Toilets

Off-grid Toilet Systems

(Fixed film reactor)

BANKA BIOLOO

Biological

Banka Bioloo toilet was developed by Bank Bio in collaboration with the Defence Research and Development Organization (DRDO), an Indian government agency, in 2008, and was implemented in India. The toilet employs a technology that uses a fixed film reactor with anaerobic bacteria to digest human waste in a Bio-digestor connected below the toilet seat. As inputs, bacteria only need below the pan because they multiply by feeding on the waste. Water and methane gas are the outputs of this system. Special care must be taken during the maintenance because detergents might kill the bacteria. Work Process: 1 No Diversion: All the waste goes directly into the Bio-digester 1 .

$ 1.5 k

Raw sludge enters the bio-digester

Liquids are further treated through filtration and sedimentation

Treated liquid can be used for flushing purposes and for irrigation.

Bacteria embedded sheets

Water collection tank

Bacteria embedded sheet partitions are flexible so that the size of each chamber is adjustable according to the number of users and the context. More users mean the first chamber needs to be bigger so that more waste can be accumulated. Moreover, if the water content is more, the middle two chambers need to be larger. It uses Bio-digester technology to decomposes human waste. When human waste comes in contact with bacteria, it takes 2-3 days to decompose and gets converted into methane and water.

2 Digestion: The Bio-digester tank consists of four different chambers separated by sheets. The sheets (fixed film reactor) separates each chamber with an anaerobic 2 bacterium embedded in it, called Psychrophile. These bacteria have the ability to survive in cold temperatures up to -55°C and multiplies by feeding on human waste. Only one-time bacteria inoculation is required to run the process. (Other toilets that use anaerobic digestion 1 ).

Effluent from previous chamber

4 Human waste

Methane Gas Treated water Released

3 Outputs 1 :

The BioLoo toilet disposes of human waste in a low-cost, and low-maintenance manner, utilizing anaerobic digestion, with bacteria embedded sheets.

12 hours

a. Water: From the last chamber, treated water goes into the storage tank, where it can be used for flushing purposes, watering plants, or safely discharged into the soil.

Compact system

Gas vent pipe Biogas

Bacteria embedded sheet Minimum solid content Clean water rich in nutrients

Inlet

Cooking purposes

The main constituents of a bio-toilet include a prefabricated shelter above the ground and a bio-digester tank.

Chamber 01 Chamber 02 Chamber 03 Chamber 04

When deposited waste comes in contact with bacteria, it gets digested and converted into water and methane gas. The concept of several chambers improves the contact time with the bacteria-embedded sheets (fixed film reactor), accelerating the degradation process and providing more surface area to break down the waste.

Usage: Attention need to be paid to cleaning products to not damage the bacteria. It is a compact, easy-to-install system that can be applied to different locations ( 2 ).

Bacteria embedded sheet

Heating purposes

First, the solid matter gets deposited in each chamber, and only the liquid matter overflows to the adjacent compartment. This way, the waste is filtrated and refined through each chamber.

b. Methane gas: Biogas is produced in minor quantities and continuously let off into the atmosphere. If generated in sufficient volumes (when the number of users increases), it can be used for various energy-intensive activities such as cooking, heating, and electricity generation.

2-3 days

Easy to install

operationalized in 12 hours.

It is compact and it can fit in any available space from 2m2. It can also be designed to be installed above ground, if required. It produces a very low electric consumption (required only for pumping water) and it does not require frequent exhaustion and drainage. Its effluent is clean water that can be recyclable to the environment or for cleaning. (Similarly compact toilets 2 ). It can be designed to be a mobile wastewater treatment systems for disaster areas, temporary construction sites, etc. It can be made to suit any drain depth. It is self-sufficient hence it can scale freely (see free scalability, 3 ). Treated wastewater contains nutrients that are beneficial to crops. These nutrients nourish the plants as well as diminish the need for fertilizers.

Treated water outlet For flushing

1_Bio-digester, #55. 2_Anaerobic digestion, #54.

1_Bio-toilet, #79; Eco-san, #87; Solar Septic, #95; Two-pit Flush, #97. 2_ Caltech Pv-Powered, #83; Earth Auger, #85 ; Nano Membrane, #91.

1_Expense/ Efficiency, #127. 2_Built Environment/ Location, #129. 3_Time/ Scalability, #151.

Off-grid Toilets

Off-grid Toilet Systems

105° C

BIOCHAR BY PYROLYSIS Thermal

2k-4k

$ 100K

Dried Waste: Moisture (30%)

Raw Waste: Moisture (70%)

Odor filter Belt dryer

Vaccum box Climate Foundation developed the conversion of human waste into Biochar using pyrolysis in 2011 and it was implemented in Kenya in 2014. This system uses a thermal process, electric combustion, to decompose human solid waste into a type of biological charcoal or Biochar. It's a heavily equipped system installed on a surface that includes a dryer, a carbonizer, and a waste treatment part to burn the human waste at high-temperature and low-oxygen levels so that Biochar is formed. Designed for the community scale, the system decomposes human waste collected from individual toilets. Heat energy produced, is used to generate electricity to run the system.

Heat recapturer

Engine

This system requires no underground pipes, generates its own energy as a byproduct, and is easily transportable by shipping containers to remote places.

Stirling engine Catalyst 2b

Carbonyzer

Biochar

Work Process 1 Diversion: By using urine-diverting pan 1 liquid and solid waste is collected in two separate containers.

This system reduces the amount of human-borne pathogens, and fertilizer is obtained as a sub-product, which reduces the cost of growing food and improves soil content. This system can be added to the sanitation chain because it can be easily transported to a remote area and process thousands of people's waste per day, making it suitable for community scale 2 . (Similar communal toilets 2 ). Because is a system highly mechanised, maintenance is an imposrt factor to consider when implemented 3 .

2 a. Separation Technique: If needed this liquid waste can be treated separately to use as liquid fertilizer. b. Feces from the urine-diverting toilets are the main inputs for the biochar reactor

3 Drying: At first, an auger screw 2 is used to transport the waste on a drying belt. The drying belt is used to reduce the moisture content from 75% to 30% at 105°C. It is installed on a vacuum chamber where a vacuum pump is used to suck hot air from the radiator through the waste and direct this hot air towards the exhaust pipe. This helps to dry the waste at a relatively low temperature. A carbon filter at the opening of the pipe is used to purify and remove further odors before discharging the gaseous substances to the surrounding. The dryer utilizes heat energy from the carbonizer 3 . 4 Combustion: The dried waste enters the combustion chamber (carbonizer--Other toilets using combustion 1 ) where the human waste is used as a fuel and burned in a rich burn condition 4 . This condition requires high temperature (300–700°C) and excess fuel in absence of oxygen. It burns partially to blacken the surface of the waste instead of burning it completely, that is, it chars (Biochar). 5 Outputs: The Carbonizer leads to the production of (see Outputs chart, 1 ): a. Mixture of gases that cannot be converted to liquid (non-condensable Syngas) i.e., hydrogen, carbon monoxide, methane, ethyne, and ethene. b. Biochar. c. Heat, which is reused at the drying belt for de-moisturizing solid waste. 6 Pyrolysis 5 : Two auger screws underneath the carbonizer transport biochar toward the collection box. The waste is initially decomposed through heating to a high temperature releasing half of the carbon as syngas while charring the remaining. Above the carbonizer, a catalyst is used at the outlets to ensure clean emission of gases. This is done by oxidizing the gases 6 . 7 Usage: The biochar is extracted from this carbonizer chamber and can be used for soil amendments or as a fuel source.

Carbonizer Temperature (300–700°C)

Gasifier

Vacuum pump Carbon filter

75%

Initial moisture

Heat(105° C)

Electricity

Compact system

Syngas

Inlet

Transportation

Odor filter

Vacuum box

Belt drying

Carbonizer (300-700° C)

Stirling engine

Combustion chamber

Syngas

Soil amendments

Biochar is used for landscaping and can be used for agriculture in future. A key benefit is that when a plant is grown in Biochar, the carbon stays in the ground for up to 1000 years. Carbonizer

Stirling engine

Heat recapturing system for drying the waste

7 105°C

70%

Moisture level

Biochar

Remote Area

30%

Heat

It processes 100 kg/h of human excreta.

8 Combustion: To generate electricity, syngas is combusted in an excess air (lean-burn condition 7 ) with high temperature 9 Thermoelectric Generation: The high-temperature gas is used for the Stirling engine 8 to produce electricity. This electricity is used to power the belt dryer and auger screw.

40%~30%

Biochar can be sold for $550/ ton 300°-700°C 15m

Section AA

1_Urine-diverting pan, #43. 2_Auger Screw, #45. 3_Carbonizer, #61. 4_Rich-burn condition, #61. 5_Pyrolysis, #61. 6_Oxidizing, #62. 7_Lean-burn condition, #61. 8_Stirling Engine, #59.

7kg/h CO2 & H2O

Section BB

1_Nano Membrane, #91; RTI International, #93. 2_RTI International, #93.

1_Expense/ Efficiency, #127. 2_User/ Sharing quota, #119. 3_Technology/ Level, #145.

Off-grid Toilets

Off-grid Toilet Systems

BIOFILCOM Biological

The earth worms process feces, remove 99% of the pathogens, produce carbon dioxide and water. After the digestion process it leaves behind no more than 15% of the waste by weight, in the form of compost material.

Solid waste

The Biofil Toilet system was developed by Biofilcom in the year 2005. This project has been implemented in India, Liberia, Ethiopia, Myanmar, Uganda and Bangladesh. This system uses a biological process (aerobic digestion by tiger worms) to break human waste. The Biofil digester is the system's main component, where human waste is broken down into products such as water, carbon dioxide and wormy compost. The rectangular chamber made of brick (digester) is constructed into the ground with a conventional toilet pan on top of it. As an input, initially, one kilogram of worms per household needs to be added, which multiplies by feeding on human waste. This system is not applicable for high groundwater levels or areas prone to flooding as partially treated liquid waste flows into the ground (groundwater pollution). Work process

$ 1.2K

10-20

2kgs/toilet 1

CO2

b. Solid waste: The solid waste remains on the bedding layer containing worms for decomposition.

3 Digestion: The solid waste is decomposed in perfectly aerobic conditions 2 by a self-perpetuating population of natural macro-organisms at the bedding layer. (Vermicomposting 3 ,other systems using vermicomposting 1 )

2b CO2

Aerobic Digestion

2a Coconut Fiber

5 5a

4 Outputs: The product of decomposition is a mixture of water, carbon dioxide, and a small quantity of ‘wormy compost.’ After a few years, this layer can be shoveled out and used as fertilizer.

Gravel

5 Filtration: There are two types of liquids that are filtrated through the filtrate media which contains two layers: a bedding layer and a drainage layer. The bedding layer is the one where the worms live on the coconut husk or wood chips and the drainage layer contains finer gravel above a layer of courser gravel. a. The liquid waste flows with gravity through the filtrate media where the impurities are trapped inside different layers of filtrate and the liquid portion goes into the soil.

Liquid waste Solid waste

1 No diversion: Urine and faeces fall directly into a compartment that houses worms to break human waste efficiently in the biodigester 1 . 2 a. Separation Technique: The liquid human waste is discharged into the ground through filtrate media.

b. Sub products of aerobic digestion: the water, with the nutrients it carries, and carbon dioxide, both of which are odorless and harmless, are allowed to flow into the soil. ( Other systems that infiltrate liquid into the ground 2 )

2a Separation Technique: Both solid and liquid waste falls directly into the biodigester. 3 Digestion: Earth worms being added to initiate aerobic digestion. 5 Filtration: Both supernatant and the byproducts of aerobic digestion (water) are first filtered through dry coconut fibers and then gets further treated through gravels to finish filtered in the soil. This fact makes not recomendable to put them in close proximity (see Time/Scale, 3 ). 4 Outputs: Residue after decomposition becomes fertilizer

General considerations: Water Availability: This system is not suitable in areas where water is scarce. It require water entering the pit to ensure that the worm’s environment remains moist. Soil Infiltration: The soil must be able to absorb the daily fluid inputs and the water table must not rise into the bottom of the pit. (see Natural Environment/Site Condions, 1 ). The close proximitiy to home and low maintainance solution of the toilet ensures safety and hygene for women ( 2 ).

Most of the liquid waste infiltrated

Dry Treated waste

Wormy compost

The main drawback is the initial cost of buying the two kilograms of tiger worms needed per toilet What type of Worms can be Used? The Red (Tiger) Worm (Eisenia Fetida or its close relative Eisenia Andrei), The African Nightcrawler (Eudrilus Eugeniae) The Indian Blue (Perionyx Excavatus) (Check appropiate Climate conditions, 4 ).

Treatment plant In India, they created a few digestors containing tiger worm compartments. From here, every year they collect a huge amount of fertilizer.

Treatment plant containing several digesters to produce large quantity of fertilizer every year.

Biofill toilet cost 47% less than traditional pit latrines over a five-year period. This broke down as a 34% reduction in construction costs, and a 90% decrease in maintenance costs.

Unit Cost

Maintainance

Construction

Right now, the primary market for the Biofill Toilet in India, specifically rural communities. Other markets include Uganda and Myanmar. As of today, more than 4,500 toilets have been installed in India alone. The fertilizers from toilet can provide communities with rich compost for growing crops, according to sanitation specialists. Approximately 20% of total waste is returned to the soil in the form of compost.

Rural community Ground

Tiger Worm Toilet tanks will require desludging between every 3-5 years 1_Biodigester, #55. 2_Aerobic Digestion, #53. 3_Vermicomposting, #58.

1_Fresh Life, #89; Zero Discharge, #99. 2_Eco-san, #87; Two-pit Flush, #97.

1_Natural Environment/ Site Conditions #135. 2_User/ Profile, #117. 3_Time/ Scalability, #151. 4_Natural Environment/ Climate, #137.

Off-grid Toilets

Off-grid Toilet Systems

BIOGAS PLANT

Biological

Active expansion chamber

The Biogas plant sanitation project was developed by Naivasha Water Sewerage and Sanitation Company Ltd. (NAIVAWASS), Water Services Board (WSB), and Water Services Trust Fund (WSTF) in 2007. This project was installed in Kenya, in 2008. A set of toilets discharge into an underground fixed-dome biogas chambers where the human waste is treated through anaerobic digestion to produce biogas, compost for fertilizer, and treated liquid waste. There are two expansion chamber, one expansion chamber is full, it is kept sealed for a year, and solid-free effluent are removed for further treatment. As an input, initially, 10L of water is needed to flush the toilet. A minimum distance of 5 meters needs to be maintained between the biogas plant and the the place where this gas will be used for cooking or heating purposes.

1 No Diversion of solid and liquid waste. All the waste goes directly into the main chamber through gravity. 1 year

2 Separation Technique: When waste enters the chamber, the solid matter gets deposited at the bottom of the chamber (Sedimentation process 1 ), and the liquid portion (supernatant) can go through further treatment.

4 Usage: a. Solid waste: The accumulated waste is digested anaerobically and can be removed once a year to use as a fertilizer.

A curved shell supports more than a flat slab. Curved structural components are more rigid; the stresses are smaller in them. That's why biogas plants are often circular, fixed-domed shaped.

Passive expansion chamber (Closed)

Bus station

1000 Users

Biogas

Best use of biogas is in small restaurants and cafés where food and hot drinks are prepared. The use of biogas for heating water and electricity generation lighting is considered too complicated.

Treatment Biogas reactor Biogas pipe to kitchen Main chamber

Expansion chamber (Closed)

The supernatant can be transported to a treatment plant for further treatment through different processes: electrolysis, heating disinfection or plant-based filtration. (-) (+)

Through Electrolysis

Concrete slab cast Overflow release

Biogas

Plant based filtration (Wetland) Treatment plant

b. Biogas: There is a half-inch galvanized iron pipe connected to a nearby kitchen or cooking area where it could be used for cooking purposes or as fuel for a heating system. Biogas is a renewable, as well as a clean, source of energy. It reduces greenhouse emissions. Another biogas advantage is that unlike other types of renewable energies, the process of creating the gas is natural, not requiring energy for the generation process.

The system has a maximum capacity of 1000 users per day 1 which makes it suitable for public buildings like bus stations, train stations etc.

Work Process:

3 Digestion: There are two chambers of different sizes and capacities depending on the number of users. Both chambers are used alternately; when one expansion chamber is full, the incoming waste is diverted into the second chamber. The chamber that is full is kept sealed for at least a year. During this one year, the waste is digested anaerobically 2 , producing biogas as a byproduct. (Other systems using anaerobic digestion 1 ).

Main chamber

$ 5.7 k

The biogas plant has a volume of 54 m� with two expansion chambers. The underground structure is located about 0.5 m below the surface. The required area for the toilet building and biogas plant is approximately 10 x 15 m. The dimensions of the plant were based on a sufficient settlement of solids. The solids settle and remain in the system for digestion and biogas production. The system works like a gas-tight septic tank. The solids-free effluent flows over to the further treatment process. (Similar toilets with heavy underground infrastructure 2 )

By applying heat

Gas storage Gas Exerts a pressure and force slurry to move to the expansion tank

1_Sedimentation, #45. 2_Anaerobic digestion, #54.

Expansion chamber (Open)

The expansion chamber is used to store the sludge for a year where the solid waste (sediments) will be digested anaerobically. Because the units depend on a common infrastructure, the Scalabitity of the system is modular 2 .

Anaerobic Digestion ( Without oxygen)

Sludge from the passive expansion chamber is removed in 1 year and can be used as fertiliser.

1_ Aerosan, #69; Banka Bioloo, #71; Bio-toilet, #79; Earth Auger, #85; Eco-san, #87; Solar Septic, #95. 2_Two-pit Flush, #97.

1_User/ Sharing quota, #119. 2_Time/ Scalability, #151.

Off-grid Toilets

Off-grid Toilet Systems

CH₄

BIO-TOILET Biological

DRDO Bio-toilet was developed by the Defence Research Laboratory (DRL), India, in 2011 and was implemented in India. This system uses both biological and plant-based filtration methods to treat human waste. The system consists of two main components: a Bio tank that is placed at a lower level, where the fecal matter will be digested anaerobically, and a reed bed or a natural filtration bed where the effluent water from the tank will again be treated for further use, such as flushing or irrigation. Initially, a layer of anaerobic bacteria needs to be added for decomposition. Biogas is generated in this system which can collected and used for cooking purposes. Work Process: 1 No diversion: Both solid and liquid waste goes directly into the tank where anaerobic digestion takes place (Bio-digestor 1 ). 2 Digestion: A special bacteria inoculum is prepared for use in the biodigester (anaerobic decomposition 2 ). It contains three main types of bacteria: Psychrophilic Proteolytic Bacteria, Volatile Fatty Acids (VFA) Degrading Bacteria, and Methanogenic Bacteria. (Other systems using anaerobic decomposition 1 )

$ 0.7 k

Smaller than conventional septic tank system. Minimizes water consumption.

Filtered Grey Water

Easy Maintenance (in terms of sludge cleaning and technology needed) 4 .

Inlet Pipe

Supernatant Solid Outlet

Aquatic Plants

Effluent Water

Bacteria, Fungi, Algae

Pathogen Breakdown

The limitations of small Biodigester:

CH₄

Filtration

Reed bed

c. Methane gas: Methane gas can be collected to use for cooking purposes.

Reed Plant Root

4 Filtration 3 : The reed bed is made up of three gravel layers of varying sizes and various aquatic plants. This filtration media offers an additional level of filtration. (Other systems using plant-based filters 2 )

The optimal temperature for a biodigester to work properly is 38°C. It produces highly flammable gas; therefore, it is essential that at least one member of the family is thoroughly conversant with the system and capable of immediate repairs. Modern cleaning products, bleaches, antibacterial, etc., kill the anaerobic bacteria in the Biodigester.

Silty Sand Gravel 5

e Lor

Design consideration:

Black/grey Water

CO₂

b. Carbon dioxide: Carbon dioxide gas is used by the aquatic plants on the reed bed.

5 Usage : Water filtrated from the reedbed can be used for flushing as well as for irrigation.

The innovation is eco-friendly. This system can be built in all geo-climatic conditions prevalent in the country. The dimensions and internal design vary with the number of users, water availability and geo-climatic conditions.

Byproducts from the Bio-digester are 1 : a. Water: Grey water generated from the biodigester passes through a vegetation-based filter bed, a reed bed, where it undergoes a second phase of filtering.

It can be customized for individual family or community levels.

Pebbles Dry fecal waste chamber

Free technology for human faecal matter digestion. Maintenance free. Customizable & easily adoptable.

Gas Exhaust

Liquid Outlet

3 Outputs:

Bio Digestor

Effluent Liquid

Anaerobic bacteria are affected by temperature within the digester. Different groups of bacteria survive within specific temperature ranges. In order to insulate the digester from wide temperature fluctuations at a low cost, the digester is placed in an excavated installation pit in the ground (be aware of the site conditions, 2 ). Part of the digester is exposed to the ambient environment in order to receive heat.

Constructed wetland

Constructed wetlands can offer a zero energy input way to get our sewage clean. Constructed wetlands are open systems; with water sitting on a soil base and movement of water through a dense filter of leaf litter and plant stems. This means that they are very resilient to sludge overloading and hydraulic shock loading Collection tank: Water for flushing purpose

The bio-digester container should be sealed so no water or gas can enter or leave the chamber uncontrolled. This will help to secure the oxygen-free environment necessary to start the anaerobic digestion process. Each unit requires 12 m2 f wetlands which need to be consider for the scalability of the system 3 . 1_Bio Digester ,#55. 2_Anaerobic Digestion, #54. 3_Plant-based Filtration, # 49.

1_Banka Bioloo, #71; Biogas Plant, #77; Earth Auger, #85; Eco-san, #87; Two-pit Flush, #97. 2_Solar Septic, #95.

1_Expense/ Efficiency, #127. 2_Natural Environment/ Site Conditions, #135. 3_Time/ Scalability, #151. 4_Technology/ Level, #145.

Off-grid Toilets

Off-grid Toilet Systems

BLUE DIVERSION Bio-Electro-Chemical

The Blue Diversion Toilet was developed by Eawag/EOOS in 2011 and was implemented in Kenya and Kampala. This system uses Bio-electro chemical process, biologically activated membrane bioreactor or BAMBi, to disinfect the cleansing water for reusing it for flushing and toilet cleaning. The L-shaped Blue Diversion Toilet consists of a shallow bowl at the base, a tall back that houses a water tank and circulation system, a sink, and a shower head for cleaning; it is installed on a surface level. The urine and feces need to be collected and transported twice a week to the Resource Recovery Plant (RRP), where they are transformed into agricultural products. Initially, 60L of water needs to be added to start the process.

4 Biologically Activated Membrane 3 Bioreactor __

(+) (+)

c. Anal-cleaning water: The anal-cleansing water is diverted to the filtration chamber and recycled back to the water storage tank.

Anal cleansing water

Install

Pay

Fecal Waste

Treat Waste

5 Entrepreneur

Pay

Construct

Economy

User

Fertilizer

5¢/day/user Fertilizer

Treatment plant

Fecal Waste

Pump 1

Ultrafiltration membrane Bio reactor

5 3 Micoorganism Microfilter Purified water

(Other systems using electrolysis 1 )

The system requires just 11.5 watts of power, which is provided by a solar panel 1 . This keeps the water moving around the system with several pumps, and also powers the flushing mechanism. This machinery may complicate system’s maintainace 2 .

5 Usage: Treated water from the filter membrane is used for flushing purposes. 6 Power: The power needed to run the bioreactor and the diverting system of the pan is generated by a photovoltaic panel 7 that is installed on the roof.

Franchisor

Electrolysis

Water basin

(-) (-)

Granular activated carbon Clean water Electronics

b. Urine: Liquid waste is collected in another container that can hold 20 liters of urine and is located below the toilet pan.

4 Filtration: To recycle the anal cleansing water, this system uses a Bioreactor (Biologically Activated Membrane Bioreactor -BAMBi, 3 ) with a porous filter medium (0.005 to 0.1 micron) which is enough to retain particles, viruses, or large molecules. This filter is installed at the back of the toilet. There are four treatment stages to ensure that the water is safe for reuse: -First, the wastewater is pumped into a Bioreactor that supplies air to mix the content evenly and exert pressure so that the filtered liquid gets into the porous filter medium (ultrafiltration membrane), retaining the solid particles. Aeration, or delivery of oxygen, is also very important to prevent the growth of anaerobic bacteria 4 . - The second step is the filtration of water through an ultrafiltration membrane. - Then, in the third step, the filtered water is pumped into a chamber containing some granular activated carbon (GAC) 5 which helps to remove the traces of any organic contaminants, colour, and smell. - Finally, the fourth step of the treatment is done in an electrolysis 6 unit. The purpose of electrolysis is to remove further traces of organic matter and produce disinfectant chlorine, both of which help limit pathogens' growth during storage.

The Blue Diversion Toilet project is not only a toilet but also a sanitation business model. This business model helps to provide sanitation services to low-income people and ensures safe disposal of urine and faeces. Local entrepreneurs can offer services that will collect the separated urine and faeces and bring them to a resource recovery plant (RRP), eventually creating job opportunities. There, wastes are transformed into marketable end products such as fertilizer, and the revenue from selling the fertilizer will help to give salaries to the volunteers. (Other systems using sanitation business model 2 )

4 Electrolysis 6

a. Solid waste: When the flush or shower head is activated a lid automatically closes the feces container (which holds 15 liters) and the valves, below the pan, move into position for collecting the water for recovery and to prevent water from diluting the solid waste.

3 Collection: A team collects both solid and liquid waste from each household twice a week, and takes it to a treatment plant for generating fertilizer (see, Circular economy, 2 ).

The blue diversion sanitation system is an off-grid solution which does not require external electricity source. This toilet separates the feces and urine at source then filters the wastewater into grey water, which is usable for washing purposes.

(-) (-)

Solid waste

1 Diversion: The Blue Diversion Toilet (BDT) uses a urine diverting pan 1 to collect the urine and feces separately in two different containers beneath the pan. 2 Separation Technique: In this system, there are three separate collection points for solid waste, liquid waste, and anal-cleansing water.

$ 0.5 k

(+) (+)

Work Process:

10-12

Anal cleansing water Liquid waste

1_Urine-diverting pan, #43, 2_Circular Economy, #63. 3_ Biologically Activated Membrane Bioreactor-BAMBi, #47. 4_Anaerobic Digestion, #54. 5_Granular Activated Carbon (GAC), #48. 6_Electrolysis, #62. 7_Photovoltaic Panel, #60.

1_Caltech PV-powered, 83; RTI International, #93. 2_Fresh Life, #89.

Job

Local entrepreneurs will have opportunity to become franchisees.

Transport

business

The business model offers Blue Diversion Toilet to business entrepreneurs, landlords, and households. They have to invest in the toilet either through micro-credit or cash and their investment would be paid off in one year. In hot countries, shading and perhaps some cooling is required to keep the water temperature inside the water wall acceptable for human uses as well as for the biological activity in the reactor.

Recycle

1_Expense/ Efficiency, #127. 2_Technology Level/ Maintainance, #145.

Off-grid Toilets

Off-grid Toilet Systems

CALTECH PV-POWERED

Bio-Electro-Chemical

$ 2K

5-50

Human waste

Caltech’s Self-Contained, PV-Powered Domestic Toilet and Wastewater Treatment System was developed by the California Institute of Technology (Caltech) in 2012 and was implemented in India. This system uses an electrochemical process powered by a solar panel to break down human waste. The treatment system is placed in a 20ft long shipping container connected to Indian standard bathroom fixtures (by Kohler). The electrochemical reactor breaks down water and human waste into fertilizer and hydrogen gas. The gas is used in hydrogen fuel cells to generate electricity that provides a backup energy source for night-time operation or use under low-sunlight conditions. The treated water from this system is then reused to flush the toilet or for irrigation. 160L of flush water and one-time loading of 10kg of table salt are required to initiate the process. Backup power of 2KW is recommended in case of failure of the photovoltaic panels.

Inlet

Supernatant

Work Process: 1 No diversion of solid and liquid waste. All the waste goes into the septic tank through gravity.

2 a. Separation Technique: Through the process of particles settling down (process of sedimentation, 1 ), solid waste deposits at the bottom of the tank.

b. The contaminated liquid portion that lies above the sediment (supernatant) flows to a device through gravity, that uses electricity to start a chemical reaction for desired end products (Electrolysis 2 ). (Systems using electrolysis, 1 ) 3 a. Electrolysis: In the electrochemical reactor ( 1 ), human waste contents are oxidized at the semi-conductor anodes while the water is reduced at the metal cathode to form hydrogen. A one-time load of 10kg of table salt is placed at the electrochemical reactor ( 2 ). Chloride from table salt oxidizes to chlorine which increases the disinfection process. b. After two days of the retention period, solid waste (sediment) is taken out to go through a further composting process so that it can be used as fertilizer.

(-) (-)

5 a. Filtration: The disinfected water goes through a microfiltration system with a pore size range between 0.1 to 10μm.

(+) (+)

(-)

7 Usage: This water can be used for irrigation and for flushing purposes. 8 Oxidation products from human waste are used as liquid fertilizer.

Battery Grey water outlet

4c 3b

5a Microfiltration system

Pore size between 0.1 to 10μm.

b. Hydrogen gas produced at the electrochemical reactor flows into a device that uses hydrogen and oxygen to generate electricity, heat, and water as byproducts (Hydrogen fuel cell, 3 ). 6 Recycling: Water from the microfiltration system is then pumped to a decontaminated holding tank.

Electrolysis Grey water

7 7 7

Solar Powered Electrochemical Reactor

Electricity

(+)

4 Outputs: Products from the electrochemical reactor (see outputs chart, 2 ) : a. Oxidation products from human waste. b. Disinfected water. c. Hydrogen gas.

Sediments (Solid waste), retention period : 2days

Power : 0.77 kw 3b

Septic Holding Tank

Microfiltration system

Solar Powered Electro-chemical Reactor

Decontaminated Water Holding Tank

Decontaminated Water Holding Tank For irrigation and flushing purposes.

2a Separation Technique: The solid and liquid portion is separated through a sedimentation process, which flows to the adjacent electrochemical reactor for disinfection.

Flow through gravity into the septic tank

Retention period = 2 days

Regarding the concept of this photovoltaic toilet unit, Caltech presented two prototypes at the Delhi Fair in March 2014. One prototype is constructed in a 3m × 2.5m × 2.5m space in a modified shipping container. The other prototype is integrated with an Indian standard bathroom fixtures by Kohler. This Caltech treatment unit is also used in coin-operated automated public toilets (E-Toilet) developed by Indian technology company Eram. ( Similar compact systems, 2 ) 2.5m

3a Electrochemical Reactor: Human waste is Hydrogen disinfected at this fuel cell electrochemical reactor through an electrolysis process with the help H2 of initially added table salt. The byproduct of hydrogen gas is used in the hydrogen fuel cell to produce backup electric energy.

5a Filtration: For further removal of organic waste, grey water enters this microfiltration chamber. 7 Usage: Used for irrigation and flushing purposes.

2.5m Fertilizer Electro chemical reactor

NaCl (+) (-)

Grey water

Compact system

DIY Build

Despite easy breakdown, packaging, & shipping, the Caltech toilet with its solar panel, electrochemical reactor and hydrogen fuel cell, has been criticized as being too complicated. The Caltech system can be powered by solar panels or by connection to the electrical grid. This system can have a back electric source generated from the hydrogen fuel cell, which will help to operate the system at night or during any power cut.

Treated water

The liquid nitrogen fertilizer that is obtained from the electrochemical reactor can be used to provide the plants with the basic nutrients necessary for growth. Nitrogen is critical to plant growth and reproduction. Pasture and crop growth respond positively to increased availability of soil nitrogen.

This system could be implimented in both way, elevated as well as underground (see Site conditions, 4 ).

For flushing

1_Sedimentation, #45. 2_Electrolysis, #62. 3_Hydrogen Fuel Cell, #60.

With the help of Caltech engineers, Kohler also makes this system for rural India (see Implementation, 3 ). They realized that as effective as the toilets might be, they needed to be integrated into the culture to be accepted. Hiring sign painters, the team decorated the restroom on the inside and outside with tiles and colorful graphics that echo Indian transportation trucks.

1_Blue Diversion, #81; RTI International, #93. 2_Banka Bioloo, #71; Earth Auger, #85; Nano Membrane, #91.

1_Technology/ Type, #143. 2_Expense/ Efficiency, #127. 3_Technology/ Implementation and Development, #141. 4_Natural Environment/ Site Conditions, #135.

Off-grid Toilets

Off-grid Toilet Systems

2a Sawdust from cutting saw or residues can be used over solid waste.

EARTH AUGER

Biological

The Earth Auger Urine Diverting Dry Toilet was developed by Critical Practices LLC in 2001 and was implemented in twelve countries and four continents. The system uses a biological process, anaerobic digestion, to break down human waste. The main component of this system is the pedal-operated auger screw machine that mixes the waste with a drying agent, sawdust or sand, and shifts it to the composting bin. The user needs to add the drying agent with every flush. This system is mainly designed for a single household.

Step on the pedal to flush toilet to add sawdust

+ 1

2 Separation Technique: Solid and liquid wastes are separated by using a urine-diverting pan 1 . a. Solid waste: Once the human solid waste is deposited into the toilet, the user presses the foot pedal, which helps to mix and move the waste inside the tube acting like a processing chamber. A lever releases sawdust onto waste. An auger screw 2 mixes the sawdust with waste and pushes the waste forward to the collection bin.

1 3 When the crank is operated, the faeces, cleansing paper and automatically added sawdust are mechanically mixed by an auger screw inside the pipe and finally stored in a container. Direct handling of excreta by the user is thus not required as the whole process is crank-operated until harvest. This system is very compact. (Similar compact systems 2 )

Rotate the crank to auger/flush toilet and pull flip lever to add sawdust

There are small vents to the odor to get out and decrease foul smell in the environment (see Impact, 4 ). The auger shell body material is colored black to absorb as much heat as possible Considerations included:

3 Composting: Every rotation of the auger screw pushes the waste towards the collection bin so, inside the pipe, a partial treatment occurs due to the presence of sawdust (drying agent). Hence small amounts of partially treated solid waste exit the system with each flush and are collected in a container. Once the solid's container is full, it is replaced with a new container. The full container is sealed and put aside to complete the anaerobic process 3 for an additional six months. Here the composting time is reduced because the waste is partially treated. (Other toilets with anaerobic digestion 1 )

- Sanitary products should go into the trash, not into the toilet, as they are not made of compostable materials. - Step on the pedal to rotate the auger/flush toilet and flip the lever to add sawdust. - Check the level of solid and liquid waste in collection containers weekly. - Solid waste should not be used until it has been composted for at least six months. - It requires changes in the routine of use which may create exclusion of users 1 .

6 Months

b. Liquid waste: The liquid waste is collected in a container, and when it is full, another container is placed for urine collection. This waste can be mixed with grey water and discharged into the soil. If needed, can be used as liquid fertilizer after diluting with water.

Recommendations for use and maintenance:

3 Sawdust covers and dries the waste

$ 0.15 k

Work process 1 Diversion: This system collects solid and liquid waste separately.

2b The liquid waste gets diverted on a movable bucket and is stored under the toilet pan.

- Careful sawdust handling as it could be associated with breathing allergies.

Six months

- The pedal handle can get broken.

Challenges seem to be occurring because of misuse or poor motivation to adhere to operational instructions. Although the Earth Auger toilet was originally designed for four to six users, fifteen users were found to be using monitored toilets. Overuse can adversely affect the stability of the compost created (see Simultaneity, 2 ). __ Requires weekly monitoring to ensure proper mixing of the waste with the sawdust and prevent waste overflow. The Auger screw, hand crank and pedal (parts that move frequently) need to repair very often. (see Maintenance, 2 ).

- Aiming the urine stream into the urine diversion component might be difficult for older people and children.

The processed waste is stored in a container and stored for 6 months before applying as fertilizer

6 months

Human excreta is an excellent fertilizing potential, providing essential plant nutrients and organic matter, building soil structure and reducing erosion.

1 week Weekly maintenance

Frequent repair of moving parts

1_Urine-diverting pan, #43. 2_Auger Screw, #45. 3_Anaerobic Digestion, #54.

1_Banka Bioloo, #71; Biogas Plant, #77; Bio-toilet, #79; Eco-san, #87; Two-pit Flush, #97. 2_Banka Bioloo, #71; Caltech PV-powered, #83; Nano Membrane, #91.

1_User/ Profile, #117. 2_Built Environment/ Use, #133. 3_Time/ Maintenance and Obsolescence, #149. 4_Natural Environment/ Impact, #139.

Off-grid Toilets

Off-grid Toilet Systems

Advantages

ECO-SAN Biological

ECOSAN UDDT (Ecological Sanitation Urine Diversion Dehydration Toilet) was developed by the Society for Community Organization and Peoples Education (SCOPE) in 2006 and was first implemented in India. This double pit system uses a biological process, anaerobic digestion, to break human waste. Using a diverting pan, this system separates anal cleansing water, which flows into the ground; while liquid and solid waste are collected in two separate containers underneath the pan and treated before being used as fertilizer. Ash is used as a drying agent for flushing, and the outputs are partially treated water, liquid fertilizer and compost. Urine may be strongly contaminated by any contact with faeces, particular care should be taken to ensure that users use these toilets properly and do not introduce urine through the seats reserved for faeces or vice versa. Work Process: 1 Diversion: The two-chamber Ecological Sanitation Urine Diversion Dehydration Toilet 1 (ECOSAN UDDT) is an onsite toilet system built above the ground. This system contains an eco-pan with three collecting points from which faeces, urine and anal-cleansing water are collected separately.

2 a. Separation Technique: Urine from the urine drop hole is collected in a mud pot buried outside the toilet. b. Anal-cleansing water is infiltered into the ground (see Site conditions, 1 ) through a filter bed outside the toilet. (Other toilets which infiltrates into the ground 1 ).

$ 0.3k Toilet module: Urine and fecal diversion

50% 25%

Urine inlet

1 year

The user feels uncomfortable while anal cleaning because of a separate hole in the pan. (see User, 3 ). Users did not feel comfortable to use urine container for collecting urine during defecation. It creates dreadful odor to the sensitive people ( 2 ).

Fecal inlet

Anal-cleansing water inlet

Immediately after urination, urine needs to be diluted with water before applying to plants.

After storing for four weeks, 1:10 concentrated urine needs to be diluted with water at a ratio of 1:10.

Conversion of Faeces into Organic Fertilizer ( 3 )

2 months

Usually, there are two chambers in each Eco-San toilet. When one chamber was filled with faeces, it was kept for around two months to be composted. During this period, enough drying agent needs to be added. In order to keep the optimum ratio of Carbon/ Nitrogen, bio-waste can be added and stored for another six months. After that, to ensure complete anaerobic decomposition, the waste must be sealed for additional six months.

Composted faeces were removed from the passive chamber (closed) and spread out in the yard in direct sunlight for around seven days to make it completely dry. After drying, faeces were stored in black poly plastic bags for field application.

c. Solid waste is collected in a separate container. 3 a. Using method: After removing the lid on the drop hole, the user defecates, applies ash over the faeces, and closes the lid (the ash acts as a disinfectant and a dehydrating agent). Care is taken so that water is not entering the chamber. The first chamber containing solid waste will be closed for almost a year when it is full so that solid wastes is anaerobically digested 2 . Faeces in the closed chamber will become an ideal soil conditioner after one year. (other systems using anaerobic digestion, 2 )

Disdvantages

Toilet pan

ECOSAN UDDT uses only a very small quantity of water for anal cleansing. This system is built over the ground and will not contaminate groundwater or the atmosphere (see Impact, 2 ). From the perspective of Bangladesh, this toilet was good in waterlogged areas because faeces were managed in a dry state. No water entered the faeces chamber, as the height was more than flood level, and the structure was sealed with cement. So, it was found that Eco-San toilets would be sustainable technology in a flood-prone area.

A sufficient amount of drying agents is added

(+)

2 Months

b. When the urine container is full, it is stored, and another container is placed for urine collection. 4 Fertilization: After a year, composted faeces are removed from the chamber and spread out in the yard in the sunlight for around seven days to make them completely dry (see composting, 3 ). Then the dried faeces are stored in black poly-plastic bags for field application. The manure can be put into the trenches or pits and covered with soil before plantation.

Family members

Urine container is sealed with an airtight cap and is placed in a dark and cool room for at least two months before applying to fields.

1 year Active solid waste container

Passive solid waste container

1_Diversion/ Urine-diverting pan #43. 2_Anaerobic Digestion, #54. 3_Composting, #57.

Human waste

(+)

To maintain an optimum ratio of Carbon/ Nitrogen bio-waste and stored for at least six months.

Bio-waste

6 Months

6 Months 7 days

Anaerobic digestion

The profits from selling fertilizer varied based on the number of members in each Money family.

Spread out on the yard in the sunlight

A hole must be dug at least 15 cm from the plants to prevent destruction by direct application of fertilizer on plants, and the hole needs to be covered with soil immediately to minimize the loss of nutrients by evaporation. 1_Biofilcom, #75; Two-pit Flush, #97. 2_Banka Bioloo, #71; Biogas Plant, #00; Bio-toilet, #79.

1_Natural Environment/ Site Conditions, #135, 2_Natural Environment/ Impact, #139. 3_User/ Profile, #117.

Off-grid Toilets

Off-grid Toilet Systems

FRESH LIFE TOILET

Biological

The Fresh Life Toilet was developed by Sanergy in 2011, and they installed the first toilet in Kenya. This system uses a biological process, aerobic digestion by black soldier flies, to break human waste. The design includes two different containers under the pan to collect solid and liquid waste separately, which are taken to the treatment plant regularly. Insect-based food, biogas and fertilizer are obtained as outputs from this system. Community engagement is required to run the network for producing organic fertilizer.

The Fresh Life Toilet is a pre-fabricated sanitation facility that can be easily installed in low-income households (see Installatioon Cost, 1 ).

80-120

$ 0.30 k

1 Diversion

Transport

2 Separation Technique Stored in container 1 Month

2 Separation Technique: Solid and liquid wastes are separated by using a urine-diverting pan 1 and collected underneath the toilet pan in two types of containers: one is used to hold liquid waste, and the other is used to contain human solid waste, making collection and conversion safe and easy.

b. Liquid waste needs to be stored for two months before using them as liquid fertilizer. 5 Digestion: The residue left by the black soldiers is mixed with agricultural waste. It goes through a composting process that uses heat-loving insects to digest the waste and make organic fertilizer (thermophilic composting 4 ). Through anaerobic digestion 5 , biogas is produced. Some of the residues left by the black soldiers are compressed at high temperature and pressure to mak biomasse briquettes that are used for industrial boilers and other industrial heating applications. 6 Outputs: The biogas generated from composting is used to power the treatment plant and other operations, which helps to reduce the dependency on existing resources.

Fertilizer

Animal Food

3 Waste collection

Recycle

90% of Sanergy’s employees are Kenyan 60% of them live in the communities of serving.

Containers collected by local volunteers

Two months

Treatment plant

The waste collection team collect the waste on a regular basis. After they have replaced the waste cartridges, they take the waste to a treatment plant to convert it to fertilizer and animal food. These treated products are then sold at a lower price than the competing alternatives offered in Kenya. Essentially, this system is turning human waste into money (see Efficiency, 2 ) Most of the operations involved with the Fresh Life Toilets are run by local business people. Sanergy, developer of this system, is not only creating a more sanitary environment by providing toilets for Kenya, they are also providing jobs.

3 Waste collection: A team regularly collects the waste from each household. After replacing the waste cartridges, they take the waste to a treatment plant to convert it into fertilizer and protein for animal food (see Circular economy 2 ). (Other systems using circular economy 1 ). 4 a. Insect-based treatment: The collected waste is used to feed insects (black soldier flies) for aerobic digestion 3 . Their larvae are harvested, cleaned, pasteurized, dried, and finally packaged as an insect-based animal food called Pure Protein. (Other systems using aerobic digestion 2 ).

Economy

Toilet module installed

Work Process: 1 Diversion: This system collects solid and liquid waste separately.

User

Transported to treatment plant 4a Insect-based treatment Treated with black soldier flies Residue left by the black soldiers is mixed with agricultural waste and it is object of anaerobic digestion

2467 metric tons

of human waste were safely transferred and made into fertilizer

1134 Numbers of toilet in Kenya, 2017

Because of these toilets, over 900 jobs have been provided to Kenyan people.

+900 +

Bio-gas

Job

Opportunity

Economy

Insect-based treatment

By doing this, individuals in the community get both a source of profit and an increase in sanitation benefiting both the Kenyan people and their economy.

Bio-gas

2 months Fertiliser

Using this fertiliser

30% of the crop yield increases.

Animal food

1_Urine-diverting pan, #43. 2_Circular Economy, #63. 3_Aerobic Digestion, #53. 4_Composting, #57. 5_Anaerobic Digestion, #54.

1__Blue Diversion ,#81. 2_Aerosan, #69; Biofilcom ,#75; Zero Discharge, #99.

1_Expense/ Installation Cost,#125. 2_Expense/ Efficiency, #127.

Off-grid Toilets

Off-grid Toilet Systems

NANO MEMBRANE

Thermal

The Nano Membrane Toilet was developed by Cranfield University, UK, in 2012 and was implemented in Ghana. This system uses a thermal process, electric combustion, to break down human solid waste. The design is a compact system that can be installed anywhere without ground excavation. The main component of this system is a unique rotating mechanism, an auger screw, and an electric combustor. Solid and liquid waste are separated through sedimentation and treated individually. The liquid waste is disinfected to obtain water for flushing, and the solids are burned at high temperature to get residue as ash, which is used as a soil conditioner. This system requires a certain skill to replace the glass-hollow tubes used for condensation. Work Process: 1 No Diversion: Urine and faeces fall directly on a semi-circular toilet bowl with a unique rotating mechanism. When the toilet seat lid is closed, the semi-circular toilet bowl rotates 270 degrees and a blade gets activated, which scrapes the waste into the holding tank.

01-10

2 2b 2a

b. Heat: Used to dry solid waste and warms the coil to change the supernatant to a vapour state. 5 Recycling: The purified liquid waste in the vapour state is transferred to a distillation chamber. This chamber has four glass-hollow tubes containing catalyzers (Nano-coated hydrophilic beads 3 ) to turn the vapour into water droplets. The water fall to a collection chambers by gravity, where they are stored to be used for flushing purposes. 6 Generating electricity: There are two ways to generate electricity a. Hand Crank: Rotating a human force generator using a crank by hand to

6a 6b

generate electricity stored in a battery. Most hand crank generators create only between 5-15 watts of power. This means that for every hour of continuous hand cranking a person can run a laptop for about 6 to 10 minutes or an iPhone for about 16 minutes. b. Bicycle generator: Rotating a human force generator using a bicycle. Here the user pedals the bicycle that moves the back wheel to generate electricity stored in a battery. Pedaling a bike at a reasonable pace for eight hours generates about 100 watts of power.

Drying chamber Supernatant

Vapor liquid Hydrophilic beads

Solid waste (Sediments) Treated water

Dryer combustor

Separation Technique Through sedimentation, solids (faeces) are separated from liquids which rise to the top

Auger screw

It is advisable to open the cover of the auger screw periodically and check the screw conveyor for cracks, any reduction in outside diameter, bent or deformed screw, or material build-up. (see Maintenance, 1 )

Combustion 3 Solid waste is carried by an auger screw and burned in the electric combustor.

Sedimented solid waste

4 Outputs: The combustion leads to the production : a. Ashes: For ten users, it produces 100 g/day on average, which needs to be emptied regularly and can be safely disposed of.

Drying chamber

5 3

Waste tray Rotating flushing bowl Scrape blade

Archemidis screw

b. Liquid waste: The liquid portion (supernatant) travels through a coil that is heated by the heat energy generated from the combustion chamber, where it turns to vapour hence destroying all the pathogens and parasites. 3 Combustion: First, the heat energy from the combustion chamber helps to dry the solid waste. Then the dry waste falls into the combustion chamber, which uses electricity generated manually to burn the waste completely. Other complementary energy sources might be needed. (See 6 ) (Other toilets using combustion method are 1 )

Rotator chain Gasifier chamber No diversion a unique 270 degrees rotating mechanism to transport the human waste.

2 Separation Technique: The solid particles settle at the bottom, and the liquid waste floats on top (sedimentation 1 ). a. Solid waste: An Auger screw ( 2 ) moves the solid waste from the bottom of the holding tank to the drying chamber.

$ 0.8 k

Combustion chamber Condensation 5 Nano-coated hydrophilic beads turn the vapour into water droplets

Disinfection and Condensation In this system, liquid waste is heated and converted to a vapour state to destroy pathogens 4 . This vapour is then condensed by using nano-coated hydrophilic beads where water droplets are formed on the surface of the beads and are used for flushing purposes. Nano-coated Hydrophilic beads

Recycling 5 Water droplets from the distillation chamber are collected in a storage tank for using them as flushing purposes.

Supernatant

1_Separation/ Sedimentation #45. 2_Separation/ Auger Screw, #45. 3_Nano-coated hydrophilic beads, #61. 4_Disinfection, #51.

This system may needs an additional power supply like a solar panel or domestic-scale wind turbine.

750

Construction cost per unit

10 5

Number of user

/user/day

Daily operations cost

This compact toilet is designed for single-unit households of up to 10 people. It is meant to be used in developing countries. The glass-hollow tubes need to be changed once every three months, and the tank should be emptied whenever required. Because of these maintenance needs, the toilet is more suitable for urban areas than remote, isolated villages. (Other compact systems 2 ) 700 It is self-sufficient, so freely scalable (Scalability, 2 ).

3 months

Glass-hollow tubes (Replace every three months)

Suitable for urban areas

Not ideal for rural areas, it requires expert maintenance

Ash from biomass can be used as a fertilizer. If applied in proper doses, biochar and biomass ash have a beneficial effect on the chemical properties of soil, by adding elements like such as zinc, copper and magnesium, leading to increased crop yields.

Heat Vapour Glass-hollow tubes containing hydrophilic beads

1_Biochar, #73; RTI International, #93. 2_Banka Bioloo, #71; Caltech PV-powered, #83; Earth Auger, #85.

1_Time/ Maintenance and Obsolescence, #145. 2_Time/ Scalability, #151.

Off-grid Toilets

Off-grid Toilet Systems

RTI INTERNATIONAL

Thermal

The RTI system was developed by RTI International in partnership with Duke University, Colorado State University, Roca, and AppTech Solutions in 2012 and was tested in India. This system uses a thermal process, electric combustion, to break down human solid waste. It's a heavily equipped system installed on a ground level. An auger screw carries the solid waste towards the combustor chamber while the liquid waste falls into the holding tank through gravity, where the process of electrolysis disinfects it. This treated water is reused for flushing, while the ashes formed by burning the solid waste are used as fertilizer.

This system operates as a closed loop, with technology to treat and reuse liquids and generate electricity via a chemical-free combustion process.

50/Day

$ 2.5 k This toilet is highly mechanised and it will require specialised maintenance 1 . This could make it unsuitable for remote areas 2 .

(+) (+)

1 No diversion: Urine and faeces fall directly on an auger screw.

Photovoltaic panels

Electricity

RTI’s incinerator toilet can be operated for $0.01 – 0.06/user/day (max of 50 users per day), which is less than the approximately $0.08/day low-flush toilets currently cost in the U.S.

Combustion chamber

(+) (+)

Holding tank 01 3

Stirling engine

Supernatant Solid sediment

(-) (-) (-) (-)

Can be developed anywhere, urban or rural

Holding tank 02

Liquid Disinfection Consumes 60-80% of electrical energy Holding tank 03

(+) (+) (+) (+)

Grey water Pathogen-free ashes can be reused or safely disposed. Ashes from biomass contains nutrients that can be beneficial for plant growth.

5 Filtration of liquid waste: There are three separate holding tanks for purifying the liquid waste: Combustion chamber 6

Stirling Engine

Holding tank 01 Holding tank 02

b. Holding tank-2: This tank contains an electrochemical reactor where by using electricity, the liquid waste is purified chemically (electrolysis) and converted to treated water that overflows to the holding tank 03. c. Holding tank-3: Here, the treated water is collected and stored for flushing purposes.

Reuse liquid

Peddle to rotate the auger

Heat outlet

a. Ashes: This needs to be emptied regularly and can be safely disposed off.

a. Holding tank-1: First, the liquid waste falls directly into this tank from an auger screw. The solid particles settle at the bottom, and the liquid waste floats on top (sedimentation process 5 ). The liquid portion (supernatant) overflows to the holding tank 02.

Stirling engine

5b (-) (-)

4 Outputs: The combustion leads to the production of:

b. Heat: Some heat is used to dry solid waste, and the rest is used to generate electricity (Stirling engine 3 ) and stored in a battery to power the electrolysis process 4 for disinfecting liquid waste.

Heat

The ultimate goal of this system is to be fully self-contained so it could be used anywhere and to be developed in a way that maximizes performance and cost to users. (Other self-contained toilets 2 ).

b. Liquid waste falls directly by gravity into a holding tank. 3 Combustion of solid waste 2 : Before falling into the electric combustion chamber, the solid waste is dried by the heat from the combustion chamber (250-320 °C). This dried waste is burned at a high temperature (600-800 °C) in the combustion chamber. (Other toilets using combustion 1 ).

Drying faeces consume 60-80% of thermal energy

a. Solid waste is carried along by the auger screw towards the combustion chamber. The auger screw 1 is connected to an electric chain wheel rotator which gets activated every time the foot pedal is pressed.

Combustion

Work Process:

2 Separation Technique: After flushing, when human waste falls on the auger screw, both solid and liquid waste are separated:

Plant

(-) (-)

Electrolysis

Ashes Toilet

6 Power: This system uses photovoltaic panels 6 as a primary source of electricity. Instead of releasing the heat energy from the combustion chamber to the surrounding, this system utilizes this energy by converting it to electricity.

Ashes

Holding tank 03

Low-cost

Electrochemical liquid disinfection: Treatment time: 40 – 60 seconds/L Energy: 4-8 kJ/L Treatment volume: 60 L Users per day: 10 – 50 Power supply: 12VDC automotive battery

This toilet could be deployed in national disaster recovery programs, refugee camps, or remote locations off the electric grid. It is ideal for construction sites in low-resource areas worldwide, where migrant workers often stay for 18 to 24 months with only pit latrines. The system is also suitable for festivals, tourist sites, and other large civic gatherings.

Recycled water

For flushing

Partially treated water can be used for flushing and other non-potable applications. 1_Separation/ Auger Screw, #45. 2_Conversion/ Combustion, #61. 3_Energy/ Stirling Engine, #59, 4_Electrolysis, #62. 5_Sedimentation Process, #45. 6_Energy/ Photovoltaic Panels, #60.

1_Biochar, #73; Nano Membrane, #91. 2_Banka Bioloo, #71; Bio-toilet, #79; Earth Auger, #85; Nano Membrane, #91.

1_Time/ Maintenance and Obsolescence, #149. 2_Built Environment/ Location, #129.

Off-grid Toilets

Off-grid Toilet Systems

SOLAR SEPTIC Thermal

Solar Septic Tank was developed by the Asian Institute of Technology (AIT) in 2015 and was implemented in India and Thailand. This system uses both thermal and plant-based filtration methods to treat human waste. It consists of two main components: a top-floor standard flush toilet pan and lower-level solar septic tank connected to a solar heating device to partially disinfect the liquid waste before discharging it to the wetland unit. Solid waste is treated further to obtain fertilizer. Electricity is generated for pumping purposes by using a photovoltaic panel. Since photovoltaic panel and solar heating device are used to run the process, it is encouraged to install the system in sunny climate conditions. Work Process:

Total solid concentrations in the solar septic tanks were found to be less than those in the conventional septic tank. The direct benefits gained from the increased temperature in the solar septic tanks were a lengthened period between successive desludging and the reduced cost of septic tank sludge treatment, alongside improving the environment, which eventually minimizes the health risks.

40- Solar vacuum tubes heat pipe ( 1000L septic tank)

$ 2.6 k

04-10

Photovoltaic panel

Hot water pumped 3-5L/min/40-55° C

Methane (reusable)

The solar septic tank is made of linear low-density polyethylene material (polyethylene polymer--see embodied carbon, 4 ) with an effective volume of 1000 L. There is a central chamber of volume 70 L inside this tank made from the same polyethylene polymer material that is heated via a low-cost spiral copper coil.

1 No Diversion: Urine and faeces fall directly into the solar septic tank. 2 a. Separation Technique: Through the process of particles settling at the bottom (sedimentation 1 ), solid waste deposits at the bottom of the tank.

b. The liquid portion (supernatant) lies above sediment .

3 Solar septic tank: There is a central chamber inside this tank that is heated via a low-cost spiral copper coil connected to a solar heater. Temperature inside the tank is increased by circulating hot water generated from the solar heater and flow through the spiral copper coil.

[

Water circulate

Solar heater Sun

Hot water

Construction of Wetland

(+)

]

Disinfectant through heat

Partially treated liquid

The first layer of the constructed wetland contains two types of aquatic plants, vetiver grasses and Canna flower, that are planted at a density of 50-100 shoots/m2. The adjacent layer of the wetland is composed of soil mixture boxes with a ratio of laterite soil mixed with sawdust and powdered charcoal . Constructed wetlands offer high efficiency in removing soluble organic/ micropollutants, solids, and nutrients in the wastewater and producing a better quality of discharged wastewater.

Pump

Outlet

4 Digestion: The heat from this central chamber of the solar septic tank helps to enhance the desinfection 2 process of both solid and liquid waste. a. Solid waste: The accumulated sludge can be removed by a faecal sludge truck by opening the cover lid of the tank. The solar septic tank helps to reduce sludge accumulation by drying, thus extending the desludging period (estimated desludging every 3-5 years for one-family use, depending on the size of the tank--see Maintenance, 1 ). After removing the waste, it can be use directly as fertilizer (anaerobic decomposition 3 ). b. Liquid waste: Liquid portion (supernatant) is discharged into the constructed wetland for further treatment. (other systems using plant-base filtration, 1 ). 5 Constructed wetland 4 : The Liquid waste from the solar septic tank is evenly discharged with the help of perforated pipes installed on the top of the constructed wetland. In this way the liquid waste can flow by gravity without any energy input to the 940 L volume of the wetland (volume needed per 1000 L septic tank). The neccesity of the constructed wetland as part of the system needs to be considered 6 when increasing number of units (Scalability, 2 ). Outputs 3 :

Heating Coil Sediments (Solid waste)

Desludging period : 3-5 years

3/5 years

When there are fewer nutrients present, plants are less likely to grow properly. Liquid fertilizer is a powerful way of giving most plants a quick boost in the garden. This can also be helpful when flowering plants go into bloom.

Composition of soil for the wetland

Sand (zeolite)

Laterite soil mixed with sawdust and powdered charcoal at 80, 10, and 10%, respectively, with 5 cm of fine gravel and 25 cm of coarse gravel as an underdrain layer.

Biogas

a. Liquid fertilizer: After passing through all the layers of the wetland, liquid waste can be safely discharged into the soil or, if needed, can be used as liquid fertilizer. b. Biogas: From the anaerobic decomposition in the septic tank, 7L of methane gas per person per day can be collected to use for cooking purposes. 1_Separation/ Sedimentation, #45. 2_Disinfection,#51. 3_Anaerobic Digestion, #54. 4_Plant-based Filtration/ Constructed Wetland, #49.

1_Bio-toilet, #79.

1_Time/ Maintenance and Obsolescence, #149. 2_Time/ Scalability, #151. 3_Expense/ Efficiency, #127. 4_Natural Environment/ Impact, #139.

Off-grid Toilets

Off-grid Toilet Systems

TWO-PIT FLUSH

Biological

Two-pit Flush Toilet was developed by Sulabh International Social Service Organisation (SISSO) and Sulabh Sanitation & Social Reform Movement, and they have been constructed over the past 30 years, mainly in India, Bangladesh and Nepal. The system uses a biological process (anaerobic digestion) to break human waste. This system uses the method of an alternate two-pit system; that is, when one pit is full, the excreta is diverted to another pit. The filled-up pit is emptied after a year, during which the pathogens are inactivated and the organic matter decomposed. Biogas and digested sludge are the outputs. This toilet idea is not applicable for high groundwater levels or areas prone to flooding as liquid waste flows into the ground and might contaminate the nearest water sources. Work Process:

10-12

$ 0.3 k

3 Fecal dries over time into the closed pit

1 year

a. Liquid Waste: Liquids infiltrate into the ground through the porous materials of the pit. Attention need to be paid to the ground conditions on site ( 1 ).(Similar toilets that infiltrates liquid waste into the ground 1 ).

3 Composting: There are two pits of different sizes and capacities depending on the number of users. Both pits are used alternately; when one pit is full, the incoming waste is diverted into the second pit. The pit that is full is kept sealed for at least a year. During this one year, the waste is digested anaerobically 1 , producing biogas as a byproduct. (Other systems using anaerobic digestion, 2 ). 4 Outputs

Toilet Components Toilet chamber

Minimum 1 year

Pit-line closed 1-2 years

Too many wet pits in a small area is not recommended as the soil matrix may not be of sufficient capacity to absorb all the liquid and the ground could become water-logged (oversaturated--see Scalability, 3 ).

This technology is not suitable for areas with a high groundwater table or where there is frequent flooding. Clogging is frequent when bulky cleansing materials are used. .

Active pit section

Pit-line open Gravel layer

Supernatant

b. Digested sludge: After a year, the digested sludge is almost dry and pathogen-free, which is safe for handling as manure.

Pit wall

Drain holes

5 Usage: The digested sludge is odourless and is good manure and soil conditioner. It can be dug out easily and can be used for agricultural and horticultural purposes.

The pan should have a steep slope of 25 to 28° and a specially designed trap with 20 mm water seal (requiring only 1 to 1.5 liters of water for flushing) is installed to avoid smell coming from the pit to enter the toilet cabin.

Soil need permeable conditions

In order for the pits to drain properly, the soil must have a good absorptive capacity; clay, tightly packed or rocky soils are not appropriate 1 .

a. Biogas: If needed, the biogas produced from the digestion of the solid waste can be stored in an inbuilt liquid displacement chamber 2 . 28L/person/day of biogas are produced.

Design guidelines:

This system cant be implemented in proximity with each other

Passive Pit (Closed)

Biogas

DIY Local technology

Relatively high initial investment costs

Extraction fertilizer after a year

Y-channel Diverter

Odorless due to close pit

Moderate to high investment costs ( 2 ); very low operation and maintenance costs. The cost of the initial infrastructure could make it unaffordable for many households. (Similar toilets with heavy underground infrastructure 3 )

4b Sludge turns to fertilizer after totally drying

Squat pan

2 Separation Technique

b. Solid waste: Solid waste remains at the bottom layer of the pit, which was initially filled with 15 cm of gravel layer.

Because double pits are used alternately, their life is virtually unlimited. Flies and odours are significantly reduced (compared to pits without a water seal). Can be built and repaired with locally available materials. After the disinfection process, the stored faecal material can be used as a soil conditioner.

2a Fecal releases supernatant into soil

Unlimited life expectancy

1 No Diversion: Urine and faeces fall directly into the pit, which is lined with porous materials.

1 Fecal enters the pit through drainage

If the maximum groundwater level throughout the year remains 2 m or more below the pit bottom, and if the soil at the site is fine (effective size 0.2 mm or less), the pits should be located maintaining a minimum distance of 3 m from drinking water sources. If the water table is higher, a minimum of 10 m distance from water sources should be kept to minimize the chances of pollution. A minimum gradient of 1:15 should be provided in the connecting drains or pipes.

Solid waste Gravel 1m

Low water table : 3m minimum distance from the drinking water sources. High water table: 10m minimum distance from the drinking water sources. 1_Anaerobic Digestion, #54. 2_Separation/ Liquid Displacement Chamber, #46.

1.5m

The digested sludge not only supplies primary nutrients (nitrogen, phosphorus and potassium) and micronutrients for plant growth but also is a source of organic matter. Increasing soil organic matter improves soil structure, increases the water holding capacity of sandy soils, improves drainage in clay soils, provides a source of slow-release nutrients, and promotes the growth of beneficial soil organisms. Drinking fresh water source

2-10m

1_Biofilcom, #75; Eco-san, #87. 2_Banka Bioloo, #71; Bio-toilet, #79; Earth Auger, #85; Solar Septic, #95. 3_Biogas Plant, #77.

1_Natural Environment / Site Conditions, #135. 2_Expense/ Installation Cost, #125. 3_Time/ Scalability, #151.

Off-grid Toilets

Off-grid Toilet Systems

ZERO DISCHARGE

Biological

The zero Discharge Toilet System was developed by the Indian Institute of Technology in Kanpur, India, in 2007 and was implemented in India. This system uses a biological process (vermicomposting) to break down human waste. A specially designed separator allows to divert solid and liquid waste and treat them individually. Liquid waste is disinfected by using natural disinfectant, whereas solid waste is taken out and carried to a treatment plant- where they are first dried and goes through a further vermicomposting process. The disinfected liquid waste is reused for flushing purposes, and the solid waste is used as fertilizer after being composted. The Separator needs to be installed following specific implementation guidelines, otherwise, it could cause malfunctions.

100-125

2 Separation Technique: Solid and liquid waste is separated by using a specially designed solid-liquid separator that uses centrifugal force 1 to divert liquid waste from the solid matter.

Design Consideration

The Separator must be installed in a vertical position; therefore, the area of usage must be horizontal. If there is a problem of levelling the ground, an adjustment plate is an option to put between the support and the Separator

The horizontal distance between the WC and the Separator must be a minimum of 1 metre, and that last metre (closest to Separator) should be pitched at 5% (5 cm lowering on one meter). At further distances, the earlier part of the pipe should have a 1-2% horizontal slope. Maintaining this slope is very important because less slope could result in the solids and liquid not running off, and too much slope could result in the liquids running faster than the solids. Both cases will result in blockage. Drying and composting:

1 Flow of liquid and anal cleansing water

Urine+Water Faeces 2a

5 Supernatant inlet

a. Liquid waste separation: The geometric shape of the separator allows the formation of a thin liquid film that adheres to the curve surface of the separator due to the centrifugal force and flows outwardly directly towards the urine collection tank. b. Solid waste separation: Solid waste gravitates into the central holding compartment below the separator.

Holding tank 02

4 Outputs: Treated water is then pumped up to the overhead tank so that it can be used as flushing water.

6 Composting: After this, the solid waste is ready for vermicomposting 4 , where various species of worms are added to decompose the waste and finally turn it into a fertilizer. (Other systems using vermicomposting 1 ) LIfe Expectancy: This system declares a life expectancy over 25 years with a maintenance occurring once a year 1 .

Holding tank 01

The tank containing solid waste will have exit points that could be connected to pipes. The solid waste is sucked out and transferred into containers or trolleys. The trolleys will dump the waste into a unit identical to a concrete mixer, which already has some compost. Once adequately mixed, it is left outside and allowed to decompose aerobically for a week on its own. This pre-compost is further added to the fresh load of solid waste which helps to dry the waste faster, and the process is repeated. After several cycles, the concentrated compost is processed by worms (vermicomposting).

Solid waste

Solid waste inlet

Sucked out

1 week

Transferred into containers or trolleys.

Treatment plant

Concrete mixer

100

Holding tank 03 Adding bio waste to maintain carbon: nitrogen ratio.

3 Purification: First, the Liquid waste is collected in holding tank 01, where the solid particles settle at the bottom, and the liquid portion floats on top (sedimentation process 2 ). The liquid portion (supernatant) overflows to the adjacent tank, where a natural disinfectant is used to purify the liquid.

5 Drying: Solid waste from the holding tank 03 is transported to the treatment site where it is placed in a concrete mixer machine and mixed with existing compost and allowed to decompose outside aerobically 3 for a week. Then again, they are placed in the concrete mixer machine; this way, the drying cycle repeats for 40 days to make sure that the moisture level is reduced.

Separator

Work Process: 1 Diversion: This system collects solid and liquid waste together to be separated after.

$ 1.6 k

Centrifugal Separator

Natural disinfectant Outlet Sediments are removed periodically

Left outside for 1 week The process repeat for 40 days

Vermicompost

Outlet for solid waste

Fertilizer

After five to six days, the sediments from holding tank 02 will be removed, which is rich in nitrogen, potassium, and phosphorus. It needs to be dried before using as fertilizer. Vermicompost is the product of earthworm digestion and aerobic decomposition using the activities of micro- and microorganism's at room temperature. Vermicomposting, or worm composting, produces a rich organic soil amendment containing a diversity of plant nutrients.

6 Transferred into containers or trolleys.

For flushing

Treatment plant

This system delivers solid and liquid waste for further treatment off-site (see Impact, 2 ), and because of this needs to be located in close proximity to a vermicomposting plan (Attached scalability, 3 ).

1_Separation/ Centrifugal Force, #46. 2_Separation/ Sedimentation Process, #45. 3_Aerobic Digestion, #53. 4_Composting/ Vermicomposting, #58.

1_Aerosan, #69; Biofilcom ,#75; Fresh Life, #89.

1_Time/ Maintenance and Obsolescence, #149. 2_Natural Environment/ Impact, #139. 3_Time/ Scalability, #151.

Off-grid Toilets

Off-grid Toilet Systems

ENDNOTES 01. AEROSAN Aerosan. “About Us.” Accessed August 14, 2022. https://www.aerosantoilets.ca/about-us

101

03. BIOCHAR BY PYROLYSIS

let-evaluation-rohingya-camp-cox-s-bazar-bangladesh

07. BLUE DIVERSION

Bill & Melinda Gates Foundation. “Reinvent The Toilet Fair: India, March 2014” Accessed 16 August, 2022. https://docs.gatesfoundation.org/documents/Reinvent%20the%20Toilet%20Fair%20India%20 2014%20Technical%20Guide.pdf

Priya S, Lekshmi. “This Toilet Has No Flush & Runs on Worms! Here’s How ‘Tiger’ Can Transform India!.” The Better India. January 14, 2019. https://www.thebetterindia.com/169569/india-eco-friendly-green-toilet-waterless-gates-foundation/.

Better Living Challenge. “Creating a Blue Diversion Toilet to solve sanitation problems.” April 30, 2014. https://betterlivingchallenge. co.za/creating-blue-diversion-toilet/

Centre for Science and Environment. “Wai FSTP (based on pyrolysis Technology)”. Accessed August 14, 2022. https://www.cseindia.org/ thermal-faecal-sludge-treatment-plant-at-wai-9443

Rohit Patankar. “TIGER TOILET TECHNOLOGY.” November 13, 2019. Video, 6:58. https://www.youtube.com/watch?v=8OYktvbdRto.

Aerosan. “Aerosan Hub” Accessed August 14, 2022. https://www. aerosantoilets.ca/model

Climate Foundation. 2014. “India, Biochar and Toilet”. March 31, 2014. https://www.climatefoundation.org/india-biochar-and-toilets. html

Herzen, Brian von, and Laura Talsma, “Adding missing links in the sanitation chain: Community-scale facility to process faeces into safe biochar by pyrolysis.” Webinar, SuSanA, April 29, 2014. https:// www.youtube.com/watch?v=zc0q3nsshPc

Larsen, Andrew. Low-Cost Sanitation Solutions: A report on progress in Post-Earthquake Haiti. Norway: Fontes Foundation. 2013. https:// www.susana.org/_resources/documents/default/2-1716-a63-fsm2larsen-salt-lake-city-usa.pdf

Herzen, Brian von, and Laura Talsma. 2014. Biochar for carbon sustainability and waste management. Stanford University and The Climate Foundation, Stanford, California, USA. Accessed August 14, 2022. https://www.susana.org/_resources/documents/default/21832-b72-fsm2-von-herzen-climate-foundation.pdf

Larsen, Andrew. Urban Sanitation Solutions for High-Use, Flooded, and Difficult to Serve Areas. Norway: Fontes Foundation. 2013. https://www.susana.org/_resources/documents/default/2-1716-andrewlarsen1susanaforumentirereport.pdf SuSanA. “Low-Cost Sanitation for Emergencies, tested in Haiti (Aerosan, USA and Haiti).” Accessed August 14, 2022. https:// forum.susana.org/106-user-interface-technology-innovations/3425-low-cost-sanitation-for-emergencies-tested-in-haiti-aerosan-usa-and-haiti?start=%1$d&setGT=0 Sustainable Sanitation Alliance (SuSanA). “Andrew Larsen: Low-cost sanitation for emergencies (Aerosan, USA) - Part 2.” March 25, 2014. Video, 7:44. https://www.youtube.com/watch?v=oh6nldqiwB8

02. BANKA BIOLOO International WaterCentre. “Banka BioLoo - Sanjay Banka.” August 12, 2020. Video, 5:01. https://www.youtube.com/watch?v=qQCPWwnYsXk&ab_channel=InternationalWaterCentre Namati. “Banka BioLoo Ltd, is a for profit sanitation product manufacturing and service provider.” Accessed August 15, 2022. https:// namati.org/network/organization/banka-bioloo-ltd/ Rotary. “A new project to provide Bio Toilets in India.” Accessed August 15, 2022. https://www.rotaryclubcaloundra.com.au/ Shrachi Ecopal. “Technology.” Accessed August 15, 2022. https:// www.shrachiecopal.com/technology

Talsma, Laura. “Conversion of human waste into biochar using pyrolysis at a community-scale facility in Kenya (Stanford University and Climate Foundation, USA and Kenya)”. SuSanA. August 26, 2013. https://forum.susana.org/169-production-of-biochar-fuel-or-electricity/5430-conversion-of-human-waste-into-biochar-using-pyrolysis-at-a-community-scale-facility-in-kenya-stanford-university-and-climate-foundation-usa-and-kenya

04. BIOFILCOM Bill & Melinda Gates Foundation. “Reinvent The Toilet Fair: India, March 2014” Accessed 16 August, 2022. https://docs.gatesfoundation.org/documents/Reinvent%20the%20Toilet%20Fair%20India%20 2014%20Technical%20Guide.pdf

05. BIOGAS PLANT Enliveeducation. “Fixed dome type biogas plant.” April 09, 2012. Video, 1:47. https://www.youtube.com/watch?v=PmBx5Zo8KZo&ab_channel=Enliveeducation Onyango, P. and C. Rieck. “Public toilet with biogas plant and water kiosk Naivasha, Kenya - Case study of sustainable sanitation projects.” Sustainable Sanitation Alliance (SuSanA), 2010. https://www. susana.org/_resources/documents/default/2-131-en-susana-cs-kenya-naivasha-biogas-public-toilet-final-2009.pdf Onyango, P. and C. Rieck. “Public toilet with biogas plant and water kiosk Naivasha, Kenya - Case study of sustainable sanitation projects.” SuSanA. Accessed August 15, 2022. https://www.susana. org/en/knowledge-hub/resources-and-publications/case-studies/ details/131 The Leafy Agenda. “Biogas in Kenya.” Last modified February 17, 2013. https://theleafyagenda.wordpress.com/2013/02/17/biogas/

06. BIO-TOILET Bajracharya, Nasana. “Kathmandu’s smart toilets give dignity to workers, confidence to women users.” Online Khabar. March 14, 2021. https://english.onlinekhabar.com/kathmandus-smart-toilets-give-dignity-to-workers-confidence-to-women-users.html BSA. “Solution: Bio-Tank Cum Reed.” Accessed August 15, 2022. http://www.biotoilet.biz/solution-bio-tank-cum-reed/

Biofilcom. Accessed August 11, 2022. https://www.biofilcom.net/ our-products/.

DRDO. “DRDO Biotoilet for plains.” Accessed August 15, 2022. https://www.drdo.gov.in/drdo-biotoilet-plains

Guilbert, Kieran. “Tiger Worm Toilets Turn Poo into Fertiliser in Crowded Cities and Refugee Camps.” Reuters. March 8, 2017. https://www.reuters.com/article/health-sanitation-africa-idUKL5N1GJ215.

Lowimpact. “Reed beds – introduction.” Accessed August 15, 2022. https://www.lowimpact.org/categories/reed-beds

Hill, Jake. “The Tiger Toilet Turns Waste into Fertilizer.” BORGEN. March 21, 2021. https://www.borgenmagazine.com/the-tiger-toilet/. International Training Network Centre (ITN-BUET) and Bangladesh University of Engineering & Technology. “Report: Biofil Toilet Evaluation - Rohingya Camp, Cox’s Bazar, Bangladesh.” ReliefWeb. July 11, 2020. https://reliefweb.int/report/bangladesh/report-biofil-toi-

SlideShare. “The use of reed beds for the treatment of sewage and wastewater.” Accessed August 15, 2022. https://www.slideshare.net/ FaisalAhmedBappi/the-use-of-reed-beds-for-the-treatment-of-sewage-and-wastewater The Food Forest. “Composting Toilet & Reedbed Systems.” Accessed August 15, 2022. https://www.foodforest.com.au/fact-sheets/planning-your-house/composting-toilet-and-reedbed-systems/

Eawag. “Wastewater.” Accessed August 14, 2022. https://www. eawag.ch/en/research/humanwelfare/wastewater Eawag. “The Blue Diversion Toilet Business Model.” Accessed August 14, 2022. https://www.eawag.ch/en/department/ess/projects/business-model-thinking-for-converting-vcnew-technologies-into-poverty-alleviation/blue-diversion-toilet-business-model/ He Eric. “Is pursuit of high-tech innovations “Diverting” our attention from issues at hand? An analysis of the Blue Diversion project.” SAIS. February 11, 2020. http://www.saisperspectives.com/2020-issue/2020/2/11/is-pursuit-of-high-tech-innovations-diverting-ourattention-from-issues-at-hand-an-analysis-of-the-blue-diversionproject Larsen, Tove A., Heiko Gebauer, Harald Gründl, Rahel Künzle, Christoph Lüthi, Ulrike Messmer, Eberhard Morgenroth, Charles B. Niwagaba, Bernhard Ranner, “Blue Diversion: a new approach to sanitation in informal settlements.” Water, Sanitation and Hygiene for Development 5, No. 1 (March, 2015): 64-71. https://doi. org/10.2166/washdev.2014.115 Pahwa, Brij. “A ‘Blue’ Diversion That Could Help Keep India Clean.” BW Businessworld. November 29, 2016. https://www.businessworld.in/article/A-Blue-Diversion-That-Could-Help-Keep-IndiaClean/29-11-2016-109000/ Sandec Eawag. “Overview of the Blue Diversion sanitation system.” March 20, 2014. Video, 2:30. https://www.youtube.com/ watch?v=fjKGcVzqCjk Sandec Eawag. “The Blue Diversion business model.” March 20, 2014. Video, 9:29. https://www.youtube.com/ watch?v=0TQW6RVG70g Tobias, Robert, Mark O’Keefe, Rahel Künzle, Heiko Gebauer, Harald Gründl, Eberhard Morgenroth, Wouter Pronk, Tove A. Larsen. “Early testing of new sanitation technology for urban slums: The case of the Blue Diversion Toilet.” Science of the Total Environment 576, (Janury 2017): 264-272. https://doi.org/10.1016/j.scitotenv.2016.10.057 Tribecraft. “Blue Diversion Toilet.” Accessed August 14, 2022. https:// www.tribecraft.ch/en/craft/works/blue-diversion-toilet Various Authors. Blue Diversion Autarky, a self-sustaining grid free toilet - Various documents on results from research grant. Poster. SuSanA. April, 2015. https://www.susana.org/en/knowledge-hub/ resources-and-publications/library/details/2237 Winston, Anna. “Blue Diversion Toilet aims to improve sanitation with built-in Filtration system.” Dezeen, April 6, 2015. https://www.

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Off-grid Toilets

dezeen.com/2015/04/06/blue-diversion-toilet-eoos-eawag-sanitation-water-filter/

08. CALTECH PV-POWERED Bill & Melinda Gates Foundation. “Reinvent The Toilet Fair: India, March 2014” Accessed 16 August, 2022. https://docs.gatesfoundation.org/documents/Reinvent%20the%20Toilet%20Fair%20India%20 2014%20Technical%20Guide.pdf Romell, Rick. Milwaukee Journal Sentinel. “Kohler Helps Caltech in Quest to Reinvent Toilet for World’s Poor.” January 18, 2014. https:// archive.jsonline.com/news/topstories/kohler-helps-caltech-in-questto-reinvent-toilet-for-worlds-poor-b99184547z1-241042421.html/ The Times of India. “World’s First Solar-Powered Toilet Set for India Launch: India News - Times of India.” March 14, 2014. https://timesofindia.indiatimes.com/india/worlds-first-solar-powered-toilet-setfor-india-launch/articleshow/32002202.cms. Walker, Alissa. Gizmodo. “Kohler Is Manufacturing a Solar-Powered Toilet with the Gates Foundation.” November 20, 2014. https://gizmodo.com/kohler-is-manufacturing-a-solar-powered-toilet-withthe-1660628904.

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Woo, Marcus. “Caltech Wins Toilet Challenge.” Caltech. August 15, 2012. https://www.caltech.edu/about/news/caltech-wins-toilet-challenge-23635

09. EARTH AUGER EarthAuger. “EarthAuger Community Systems in India.” Accessed August 15, 2022. http://www.earthauger.org/indiacommunity.html Fioravanti, Marcos. “The Earth Auger Toilet: Innovation in waterless sanitation - Various documents on results from research grant.” SuSanA. October, 2013. https://www.susana.org/en/knowledge-hub/ resources-and-publications/library/details/1779 Fioravanti, Marcos. The Earth Auger. Ecuador, Fundación In Terris, 2013. https://www.susana.org/_resources/documents/default/21779-taladro-de-la-tierra-english-lw.pdf Fioravanti, Marcos. “A mechanized, pedal operated urine diverted dry toilet.” Presentation, Durban, South Africa, 2012. https://www. susana.org/_resources/documents/default/2-1779-c33-fsm2-fioravanti-fundacion-terris-ecuador.pdf SuSanA. “The Earth Auger Toilet: urine-diverting composting toilet (Fundacion In Terris, Ecuador) - updates on progress.” Accessed August 15, 2022.

10. ECO-SAN Bill & Melinda Gates Foundation. “Reinvent The Toilet Fair: India, March 2014” Accessed 16 August, 2022. https://docs.gatesfoundation.org/documents/Reinvent%20the%20Toilet%20Fair%20India%20

Off-grid Toilet Systems

2014%20Technical%20Guide.ppd S. Sarwar, M.R. Shaibur and I. Ahmmed. “Performance of ecological sanitation (eco-san) technology in Keshabpur upazila of Bangladesh.” International Journal of Experimental Agriculture 10, no. 1 (January 2020). https://www.researchgate.net/publication/341701579_PERFORMANCE_OF_ECOLOGICAL_SANITATION_ ECO-SAN_TECHNOLOGY_IN_KESHABPUR_UPAZILA_OF_BANGLADESH

11. FRESH LIFE Borjas, Daniel. “Fresh Life Toilets: Toilets for Kenya.” The Borgen Project. November 3, 2017. https://borgenproject.org/fresh-life-toilets-toilets-for-kenya/ Couder, Louise. “Presenting the Fresh Life Toilet!.” Sanergy. August 30, 2011. https://www.sanergy.com/2011/08/30/presenting-thefresh-life-toilet/ Oxfam. “The Fresh Life Toilets for Safe Sanitation in Schools.” Apr 26, 2016. https://kenya.oxfam.org/latest/image-story/fresh-life-toiletssafe-sanitation-schools Sanergy. Accessed August 15, 2022. https://www.sanergy.com/

12. NANO MEMBRANE Bill & Melinda Gates Foundation. “Reinvent The Toilet Fair: India, March 2014” Accessed 16 August, 2022. https://docs.gatesfoundation.org/documents/Reinvent%20the%20Toilet%20Fair%20India%20 2014%20Technical%20Guide.pdf Canfield Water Science Institute. “Cranfield Nano Membrane Toilet.” March 19, 2014. Video, 3:40. https://www.youtube.com/watch?v=iX0jAn-iNng&ab_channel=CranfieldWaterScienceInstitute Carnfield Universities. “Reinventing the toilet – helping to solve sanitation issues in low income countries.” Accessed August 15, 2022. https://www.cranfield.ac.uk/case-studies/research-case-studies/ nano-membrane-toilet Civil Engineer. “Α waterless toilet, funded by the Bill Gates Foundation.” December 09, 2016. https://www.thecivilengineer.org/news/ waterless-toilet-funded-by-the-bill-gates-foundation Hannah, Furlong. “This Waterless Toilet Is Helping Ghana Turn Poop Into Power, Clean Water.” Sustainable Brands. February 10, 2016. https://sustainablebrands.com/read/product-service-design-innovation/this-waterless-toilet-is-helping-ghana-turn-poop-into-powerclean-water Hennigs, Jan, Kristin T. Ravndal, Thubelihle Blose, Anju Toolaram, Rebecca C. Sindall, Dani Barrington, Matt Collins, Bhavin Engineer, Athanasios J. Kolios, Ewan McAdam, Alison Parker, Leon Williams, Sean Tyrrel. “Field testing of a prototype mechanical dry toilet flush.”

Science of the Total Environment 668, (June, 2019): 419-431. https:// doi.org/10.1016/j.scitotenv.2019.02.220 Mick Redman. “Field Testing Photos with VFX.” November 20, 2018. Video, 0:30. https://www.youtube.com/watch?v=PHrqHlArNdc&ab_ channel=MickRedman StartUp Magazine. “Bill Gates Launches Reinvented Toilet Expo Showcasing New Pathogen-Killing Sanitation Products That Don’t Require Sewers or Water Lines.” November 13, 2018. http://startupmagazine.co.ke/2018/11/13/bill-gates-launches-reinvented-toiletexpo-showcasing-new-pathogen-killing-sanitation-products-thatdont-require-sewers-or-water-lines/

13. RTI INTERNATIONAL A Better Toilet. “RTI Toilet Animation (2015).” Accessed August 16, 2022. Video, 1:08. https://vimeo.com/123623042 Bill & Melinda Gates Foundation. “Reinvent The Toilet Fair: India, March 2014” Accessed 16 August, 2022. https://docs.gatesfoundation.org/documents/Reinvent%20the%20Toilet%20Fair%20India%20 2014%20Technical%20Guide.pdf Phil, Caruso. “Sustainable Toilets: A Pleasant Solution to a Foul Problem.” Digital Initiative. November 04, 2016. https://digital.hbs.edu/ platform-rctom/submission/sustainable-toilets-a-pleasant-solutionto-a-foul-problem/ RTI International. “Designing a waste treatment system for off-grid sanitation needs.” Accessed August 16, 2022. https://www.rti.org/ impact/reinventing-toilet RTI International. “RTI International receives additional funding from Gates Foundation to advance toilet reinvention.” November 18, 2013. https://www.rti.org/news/rti-international-receives-additional-funding-gates-foundation-advance-toilet-reinvention Sellgren, Katelyn L. Christopher W. Gregory, Michael I. Hunt, Ashkay S. Raut, Brian T. Hawkins, Charles B. Parker, Ethan J. D. Klem, Jeffrey R. Piascik, Brian R. Stoner. “Development of an Electrochemical Process for Blackwater Disinfection in a Freestanding, Additive-Free Toilet.” USA: RTI Press, 2017. https://doi.org/10.3768/rtipress.2017. rr.0031.1704

14. SOLAR SEPTIC Bill & Melinda Gates Foundation. “Reinvent The Toilet Fair: India, March 2014” Accessed 16 August, 2022. https://docs.gatesfoundation.org/documents/Reinvent%20the%20Toilet%20Fair%20India%20 2014%20Technical%20Guide.pdf Koottatep, Thammarat, Tatchai Pussayanavin, Chongrak Polprasert. “Nouveau design solar septic tank: Reinvented toilet technology for sanitation 4.0.” Environmental Technology & Innovation 19. May, 2020. https://doi.org/10.1016/j.eti.2020.100933 MDPI. “Solar Septic Tank: Next Generation Sequencing Reveals Effluent Microbial Community Composition as a Useful Index of System Performance.” Accessed August 14, 2022. https://www.mdpi. com/2073-4441/11/12/2660/htm PubMed. “Nouveau design solar septic tank: Reinvented toilet technology for sanitation 4.0.” Accessed August 14, 2022. https:// pubmed.ncbi.nlm.nih.gov/32775556/ ScienceAsia. “Solar septic tanks: A new sanitation paradigm for Thailand 4.0.” Accessed August 14, 2022. http://dx.doi.org/10.2306/ scienceasia1513-1874.2018.44S.039

15. TWO-PIT FLUSH Ahuja, Aastha. “Swachh Bharat Abhiyan: What Are Twin Pit Toilets?.” NDTV. November 18, 2020. https://swachhindia.ndtv.com/swachhbharat-abhiyan-what-are-twin-pit-toilets-53023/ Akvopedia. “Twin Pits for Pour Flush.” Accessed August 15, 2022. https://akvopedia.org/wiki/Twin_Pits_for_Pour_Flush Amit Kumar. “Twin pit toilet.” April 12, 2017. Video, 3:06. https:// www.youtube.com/watch?v=I7kIzNXD5Kc&ab_channel=AmitKumar Bejjanki , Vijeta Rao. “State of Knowledge Report on Twin Leach Pit Toilets.” Accessed August 15, 2022. https://www.communityledtotalsanitation.org/sites/communityledtotalsanitation.org/files/TwinLeachPitToilets.pdf ENVIS. “Two-pit System.” Last modified December 03, 2016. http:// www.sulabhenvis.nic.in/Database/TwopitSystem_7025.aspx#

SuSanA Secretariat. “Electrochemical disinfection unit for treatment of liquid waste.” Flickr. March 22, 2014. https://www.flickr.com/photos/gtzecosan/13359537583/in/album-72157642797170955/

IRC. “Technical guidelines on twin pit pour flush latrine.” Accessed August 15, 2022. https://www.ircwash.org/sites/default/files/323.192TE-12021.pdf

Wikipedia. 2022. “Incinerating toilet.” Wikiwand. Accessed August 16, 2022. https://www.wikiwand.com/en/Incinerating_toilet

PIB India. “Twin Pit Technology Campaign.” May 28, 2018. Video, 1:06. https://www.youtube.com/watch?v=dFpF2RK-gO4&ab_channel=PIBIndia

Wikipedia. 2020. “RTTC Toilet Developed by RTI International.” Wikimedia Commons. Last modified October 31, 2020, 00:37. https:// commons.wikimedia.org/wiki/File:RTTC_Toilet_Developed_by_RTI_International.jpg

Shantz, Andrew, “Learning Brief: Alternating Twin-Pit Latrines– A solution to the emerging faecal sludge challenge?.” SNV. February, 2020. https://snv.org/assets/explore/download/2020-alt-twin-pit-

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Off-grid Toilet Systems

latrines-cambodia.pdf SlidePlayer. “Pour-flush Toilets linked to Twin-pits.” Accessed August 15, 2022. https://slideplayer.com/slide/5946899/

16. ZERO DISCHARGE Centre for Science and Environment. “Zero discharge toilets at residence in Krishna Dham, Aligarh.” Accessed August 16, 2022. https:// www.cseindia.org/zero-discharge-toilets-at-residence-in-krishnadham-aligarh-3784 DRDO. “Biodigester for Indian Railways.” Accessed August 16, 2022. https://www.drdo.gov.in/biodigester-indian-railways IIT Kanpur. “Sponsored Projects (2009-2014).” Accessed August 16, 2022. https://www.iitk.ac.in/ce/CIVIL/Sponsored_Research.htm “India trials new train toilet.” Plumbing Connection. April 04, 2009. https://plumbingconnection.com.au/india-trials-new-train-toilet/ Jha, Srinand. “Discharge From New Bio-Toilets on Indian Trains No Better Than Raw Sewage: Study.” The Wire. November 23, 2017. https://thewire.in/government/discharge-new-bio-toilets-indiantrains-no-better-raw-sewage-study

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Madan. “Indian railway installing eco-friendly ‘zero toilet discharge’ on coaches to keep tracks clean.” Planet Custodian. June 16, 2015. https://www.planetcustodian.com/indian-railway-installingeco-friendly-zero-toilet-discharge-on-coaches-to-keep-tracksclean/3250/ Misra, Savvy Soumya. “Zero-waste toilets by IIT Kanpur.” Business Standard. June 14, 2013. https://www.business-standard.com/article/ economy-policy/zero-waste-toilets-by-iit-kanpur-108020501016_1. html Rao, Srinivasa. “Bio toilets presentation.” SlideShare. February 20, 2014. https://www.slideshare.net/srguduru/bio-toilets-presentation Srinivasan, R K. “Indian Railways’ experimentation with eco-friendly toilets.” Down To Earth. March 31, 2008. https://www.downtoearth. org.in/coverage/indian-railways-experimentation-with-ecofriendly-toilets-4386 Tiwari, Sachin and Praveena Sridh. “Zero Discharge Green Toilet System in Kumbh Mela – 2013 A Study.” Chennai, India: Urbane Industries, 2013. https://contestedrealities.files.wordpress.com/2017/11/ zdts_in_km_2013_a_study_1-2.pdf

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Comparative Classification

USER

Profile

USER

Profile

Share Governance

EXPENSE

Agents

Cost

Efficiency

BUILT ENVIRONMENT Location

Status

Use

EXPENSE

Share Governance

NATURAL ENVIRONMENT Site

Weather

Impact

Agents

Cost

Efficiency

TECHNOLOGY

Implement

Type

Level

BUILT ENVIRONMENT Location

Status

Use

TIME

Usage Maintainance Scale

This chapter proposes a comparative classification of all the systems in relation to users and contextual conditions. The chapter starts with a taxonomy of the significant conditions for deciding what system to apply. An evaluation of the systems has been done to classify which system suits better under what conditions.

Off-grid Toilets

Comparative Classification

GENERAL INFORMATION i) Access to basic sanitation

The United Nations Sustainable Development Goal number 6 established the wish of achieving equitable sanitation for all and the end of open defecation by 2030. The dimension of this problem is staggering and the consequences of this situation for human health and the environment are appealing: 80% of the water resulting from human activities is directly discharged into rivers or sea without any pollution removal, becoming a sickness transmitter responsible for nearly 1,000 children deaths per day. ¹ The distribution of this problem is a trustworthy way to reflect global inequality as it can be seen in the map below.

Percentage of population without access to safe sanitation by regions2

11%

31%

67%

North America

Europe, Central Asia

East Asia, Pacific

Latin America, Caribbean

South Asia

Sub-Saharan Africa

Evolution of rural and urban sanitation coverage⁵

With 45% of the global population living in rural environments, the differences of this problem between rural and urban conditions are huge. Only 62% of the urban population and 44% of the rural one have access to safely managed sanitation.

Urban 57%

36%

44%

62% 22% 26%

16%

8% 3% 1%

19%

8% 5% 2%

109

22%

29%

2020

2015

Access to safe sanitation is a fundamental human right

Rural

Safely Managed Sanitation Basic Sanitation Limited Sanitation Unimproved Sanitation Open Defecation

7% 14% 13%

2015

2020

110

Proportion of population practising open defecation till 20216

1.7 billion, 22.36% of the global population people do not have basic sanitation services, such as private toilets or latrines. 100%

No data

Senegal

10.7

9.78

7.3

4.6

3.7

0.2

South Africa

>75%

11.2

Philippines

50-75%

17.0

Uganda

25-50%

17.7

Indonesia

10-24%

Zimbabwe

0-9%

Access to basic sanitation by countries4

Côte d'Ivoire

Nigeria

18.66

Pakistan

23.5

Ethiopia

25.2

Ghana

Nepal

Myanmar

494 million people, or 6.3 percent of the world population, were still practicing open7 defecation

64.0

Afghanistan

Chad

103 million global population lack access to safely managed sanitation3

Off-grid Toilets

Comparative Classification

GENERAL INFORMATION

ii) Unsafe sanitation across the globe

Unsafe sanitation situation around the world in significantly over populated countries BRAZIL

Rio de Janeiro

Total population = 6.7 million

22 millions (30% of the population) of Rio is not connected to a formal sanitation1

111

LATIN AMERICA AND CARRIBEAN Total population = 666 million

110 million (16.5% of total population) have no access to improved sanitation2

Unsafe sanitation practices around the globe

The lack of proper infrastructure force people across the globe to get involved in unsafe sanitation practices to accommodate their sanitation necessity. Open defecation, untreated disposal of human waste, inevitable contamination of water bodies and high-quotes of sharing facilities, are just some of these practices with lethal consequences.

INDIA

SOUTH AFRICA

Total population = 1,000,000+

Total Population = 400,000+

Dharavi, Mumbai

One toilet is shared by 1440 people at Dharavi6 = 1440x

INDIA

Total population = 1.38 billion

207 million (15% of the total population) in India defecates in the open3 BANGLADESH

Dhaka

Total population = 22 million

Exposed solid waste is responsilbe for 49 vector borne diseases4

2.6 billion around the world5 lack access to a toilet at home 0.5 Billion(500,000,000) People =

Global Population 7.9 billion

Khayelitsha, Cape Town

One toilet is shared by twenty five families on average9 = 25x

NIGERIA

Ajegunle, Lagos

BANGLADESH Karail, Dhaka

Total population = 250,000+

Almost 215,000 dwellers use shared toilets7

Total population = 1,555,000

Only 15% of the required sanitation amenities available10

15%

KENYA

Kibera, Nairobi

Total Population = 700,000+

Eigthy five households shared one toilet12 = 85x

People poo in bags, tie them and throw them away, which is known as "flying toilets” 13

REPUBLIC OF CONGO

Total population = 1,800,000

86%

Shared Toilet

14%

Personal Toilet

Vashantek, Dhaka

Total population = 31,000

Over 70 people compete for a latrine8 = 70x

Makoko, Lagos

Total population = 86,000

People defecate, bathe and fish on the lagoon11

1.6 million (91.8% of total population) has no basic sanitation14

91.8%

112

Off-grid Toilets

Comparative Classification

GENERAL INFORMATION iii) Global sharing quota

145�

INDIA Govandi, Mumbai

Shared sanitation is currently excluded from the United Nation's definition of safely managed sanitation. 113

1440�

INDIA Dharavi, Mumbai

Shared sanitation is currently excluded from the United Nation's definition of safely managed sanitation, one of its Sustainable Development Goals for 2030. This exclusion is motivated by the assumption that shared sanitation fails to safely deliver services, but there are many examples of it working well in practice. On the one hand, the goal is framed against an urban reality where hundreds of millions of people regularly rely on shared sanitation and where the alternative is often open defecation. On the other hand, practices of sharing sanitation increase users' health hazards, as has been demonstrated by the Covid 19 pandemic.

HUMAN DEVELOPMENT INDEX No Data 1 - 0.85 0.849 - 0.55 < 0.55

100 people per toilet

XXX AAAA BBBB

Total people competeitng for a single toilet unit Country Name of the place

100

70��

�

BANGLADESH Vashantek, Dhaka

UGANDA Kampala

103�

2187�

KENYA Mukuru, Nairobi

LIBERIA West Point, Monrovia

17�

GHANA Fante Town, Kumosi

49�

SOUTH AFRICA Langrug, Capetown

250�

KENYA Kibera, Nairobi

100�

KENYA Mathare, Nairobi

71��

BANGLADESH Karail, Dhaka

114

Off-grid Toilets

Comparative Classification

CLASSIFICATION

A few parameters have been considered as important when deciding which of the off-grid toilet sanitation systems to implement. These parameters have been classified under six categories: user, expense, built environment, natural environment, technology and time. Under the USER category, conditions such as user profile, sharing quota and kind of governance have been considered. Under the EXPENSE category, the agents involved (developer and founders), the cost of the systems and their efficiency (the relation

between inputs and outputs), were explore across all the systems.

pollutants and residues, has been investigated comparatively.

The BUILT ENVIRONMENT category explores how the systems suit differently to location (urban, suburban, exurban or remote), building statuses (formal, informal, slum or squatter), or different uses.

The TECHNOLOGY category explains the implementation level and location of the systems studied, the type of technology used and the level of technology needed (in their fabrication, implementation and maintenance).

Under the NATURAL ENVIRONMENT category how the systems adapts to different sites, depending of the geology of the place and climates, and what is the impact of the systems in terms of carbon footprint and emissions of

By last, the TIME category explores the differences of the systems based on use term, maintenance and obsolescence periods and the capacity and limitations of the systems for being scaled throughout time.

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116 USER

Profile

Share USER

EXPENSE

Governance

Agents

Cost EXPENSE

BUILT ENVIRONMENT

Efficiency

Location

Status BUILT ENVIRONMENT

NATURAL ENVIRONMENT

Use

Site

Climate NATURAL ENVIRONMENT

TECHNOLOGY

Impact

Implement

Type

TECHNOLOGY

TIME

Level

Usage

Maintainance

TIME

Scale

Off-grid Toilets

Comparative Classification

Selection by

USER Profile

Age

Regarding gender, Sustainable Development Goal number 6, which aims to achieve equitable sanitation for all by 2030, states that special attention is required for women, girls, and those in vulnerable situations. This requirement is based on multiple different factors: biological (such as menstruation and pregnancy), cultural (in particular contexts, expectations around maintaining 'dignity' and 'modesty'), and greater risk for women and girls of harassment and sexual violence in shared, community, or public toilet facilities. 1

The systems offer significant differences in the way they accommodate user’s profiles in terms of age, gender and cultural background. In terms of age, some systems require a bit of training (such as the ones with diverting pans), or may need some operation for use, making them difficult to use for children. Other systems are commonly installed raised from the ground level due to the tanks or devices located below, which may make them difficult to access for people with mobility problems. About 35% of persons aged 70 and the majority of persons over 85 years have mobility limitations.

To accomplish safer sanitation facilities for women and girls, toilets should be placed at a reasonable distance from home, with the lowest sharing quota possible and should be properly maintained and managed.

Children

Toilet systems which are tough to operate and complex in terms of usage are discouraged for childrens use. Such as systems with diverting pans or foot-pedal flushing systems or systems which need to add drying agents manually.

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Gender

Women Friendly

Adults

Every toilet systems are considered to be suitable for adults. Thus there is no limitation in terms of using, for this age group.

Elderly

Raised platforms and over-complicated operating for the toilets are not suggested for the elderly people.

Liberal

A community where people are more open to adopt novelty.

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Cultural Education

Conservative

A community that is less likely to try any social changes amongst them.

Some of these systems propose significant differences in the traditional way toilets are built and are used, which may need adaptations from the user. Depending on their education and cultural backgrounds, the users might exhibit some resistance in developing these adaptations. Communities with a more liberal education or background could be more open to welcoming routine or aspect changes brought by the new systems. Conservative communities would be more resistant to change their habits leading to unacceptance or misuse of the new toilets. Thus, cultural education may be a factor to consider when selecting the system to implement.

Not suitable for conservative minds due to: a. Unusual aspects: Presence of worms b. Change in use routine: diverting pan c. Change in use routine: need to be operated

USER Profile

Governance

Agents

Cost

NATURAL ENVIRONMENT

BUILT ENVIRONMENT

EXPENSE Efficiency

Location

Status

Use

Site

Climate

TECHNOLOGY Impact

Implement

Type

TIME Level

Usage

Maintainance

Scale

Off-grid Toilets

Comparative Classification

Selection by

USER

Sharing quota 1

Multiple factors are related to the number of users per toilet (sharing quota). Firstly, the density of inhabitants and fabrics. If population density is high and habitation space is minimal, a high sharing quota of sanitation facilities is unavoidable. Secondly, the simultaneity of use. Sometimes, even when the density of inhabitants is high, it

Private

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doesn't mean that facilities are busy. In informal settlements, which act more like bedroom neighbourhoods, inhabitants spend most of the day in other places using work or public sanitation facilities. Finally, the capacity of residents, communities, NGOs and Governments to front the required investment for the infrastructure. Most of the time, the sharing quota is not the one intended

Used by one person or family (less than 10 users)

Off-grid sanitation systems have some limitations in terms of the quota of users they can accommodate. These limitations are due to the capacity of the systems to process waste (due to storage or other restrictions of the process) or the difficulties of accommodating simultaneity of use (due to the speed of the process).

Used by a few residents and families (10 - 50 users)

1-10

4-10

Diarrhea identified an increased risk of 44% for those who shared sanitation facilities compared with those who used individual household latrines4

but the financially possible.

10-12

Shared

10-20

Communal

10-20

10-12

80-120

Profile

Governance

Agents

Cost

NATURAL ENVIRONMENT

BUILT ENVIRONMENT

EXPENSE Efficiency

Location

Status

5-50

a. Unaffordable (Shared) b. No data available c. Need big infrastructure (Communal/Public)

Limit = Range =

USER

Used in public spaces, public facilities or public events (above 300 users)

Used by many residential neighbors (50 - 300 users)

Use

Site

Climate

100-125

Implement

Type

120

2000 -4000

d. Affordable (Shared) e. Slow processing (more for Shared than Communal) f. System implemented for public use

TECHNOLOGY Impact

Public

TIME Level

Usage

Maintainance

Scale

Off-grid Toilets

Comparative Classification

Selection by

USER

Governance

Top - Down Actions that are planned and taken from the top

The selection, financing, installation, and maintenance of a shared or community facility imply communal agreements conditioned by the community's way of governance. There are three clearly different ways of making decisions, implementing, and assessing a policy or facility for the community: top-down, top-bottom-up and bottom-up.

121

In terms of the decision-making process, sometimes decisions are triggered and led by governmental organisations in response to people's necessities (we call this top-down governance). On other occasions, people don't wait for their representatives to respond to their necessities and make decisions on their behalf,

Governance type’s characteristics:

taking the initiative in the decision-making process (bottom-up processes). In these cases, the decision-making process could be highly flat (which means that the opinion of each member of the community is heard and considered), or the community leaders (considered as such for cultural reasons, any kind of recognised privilege or selected informally) could play a more determining role in the decision in behalf of the wider community (a process named as top-bottom-up). These three governance systems also have very different ways of implementation and assessment. Top-down decisions are usually implemented with little participation from the users and this usually implies an assessment with

Decision-making

TOP DOWN

TOP - BOTTOM UP

BOTTOM - UP

Implementation

(Speed)

(Participation + structure)

by Governmental Institutions. (Fast).

No users participation. (Heavily structured)

by user’s leaders or informal representatives (Medium).

Fruitful users participation (Minimally structure).

by user’s themselves. (Low).

High users participation (Loose structure).

USER Profile

poor users’ feedback. The top-bottom-up governance accommodates an implementation that can be efficiently organised for community participation. In this governance system, assessment is commanded by a constant feedback loop where every action is reconsidered after each implementation for its required adjustments. Bottom-up decisions may have a slow implementation depending on the size of the community and the possible disagreements between the members of the community in each phase. This is due to the governance's political flatness, which means the necessity to respond at any time to each member’s concerns. A slower implementation phase usually brings a better assessment and shorter feedback loops, as these loops have taken place during implementation.

Agents

Cost

b, c

(Loops)

The characteristics of the selected case studies could make them more suitable for a particular decision-making, implementation, and assessment processes. In standard solutions, implementation is fast, but assessment is usually slow.

Standardised solutions tend to be implemented by top-down decisions (led by government or NGOs) due to the fact that they might be addressing wider communities, or they just can't attend to particular requirements for each individual.

Actions that are planned and taken by same users in a democratic and equalitarian decision-making process.

b, c

Bottom - Up

NATURAL ENVIRONMENT

BUILT ENVIRONMENT Efficiency

Actions planned and taken by informal community leaders acting in behalf of the community and in close contact with the community members.

Assessment

EXPENSE Governance

Top - Bottom - Up

Location

Status

Use

Site

Climate

Other solutions may require the community's involvement in the construction and maintenance, which is easier to garner if the community owns the decision and has a way to structure themselves (so they could be more suitable for top-bottom-up structures). On other occasions, the implementation needs to be able to accommodate particular requirements stated during flat bottom-up processes, so a system that offers the possibility of customisation is required. Lets keep in mind that the indicated on the left are the Governance's types more suitable for the studied system. It doesn't mean that they cannot be applied in the other conditions, however the highly standarised or mechanised systems are quite inflexible allowing bottom-up decisions.

a. Highly customisable (Bottom-up) b. Highly standardised (Top-Down) c. Serving big communities (Top-Down) d. It needs human cooperation (Top-Bottom-Up/Bottom-Up) e. Required community involvement (Top-Bottom-Up) f. Suitable for a DIY technology (Bottom-Up)

TECHNOLOGY Impact

Implement

Type

TIME Level

Usage

Maintainance

Scale

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Off-grid Toilets

Comparative Classification

Selection by

EXPENSE

Developer

Agents

Three connected agents to consider here: users, developers, and funders. The users of a toilet can be -private, -shared, -communal and -public

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These different kinds of users refers to different sharing conditions. The sharing condition could be important for the selection of the systems because it has an impact on the way in which the system is going to be used and maintained. More resilient systems should be implemented when sharing conditions are more massive and anonymous.

The developer is the private or public organisation who authors the idea of the systems and all the processes until implementation (design, laboratory test, prototype and field-tests). Some systems are developed by private companies, which means that profit is important, and research investment needs to be paid back as private developers usually fund their own projects. In these systems, some information remains secret as part of property tenure. In other cases, research institutes are behind the systems as part of the research. On these occasions, implementation and assessment are usually part of the research as knowledge builders.

or implementation support to the developers. These funding bodies could be governmental or non-governmental organisations (NGOs) or private foundations (such as the Bill and Melinda Gates Foundation). In these cases, accruing financial benefits is at a lower priority than having a positive impact on tackling the problem.

Funding organisation

BIOFILCOM, Ghana

Cranfield University, UK

The California Institute of Technology, USA

Defence Research and Development Organisation, India

Climate Foundation, USA

Sulabh International, India

Society for Community Organization and Peoples Education (SCOPE), India

Asian Institute of Technology, Thailand

Sometimes one or more funding bodies participate in the process by providing financial Swiss Federal Institute of Aquatic Science and Technology, Switzerland

RTI International, USA

Bill & Melinda Gates Foundation, USA

Critical Practices LLC, USA

No shared sanitation is safe sanitation

Safe Sanitation

Sanergy, Kenya

Unsafe Sanitation

Banka Bio, India

Defence Research and Development Organisation, India

Indian Institute of Technology Kanpur, India

Private

Shared

one person or family

few residents of families

USER Profile

Communal many residential neighbours

Public

pedestrians, commuters, workers, etc.

Agents

Cost

Efficiency

Location

Status

Use

Site

Climate

TECHNOLOGY Impact

Implement

Type

European Union, Swedish International Development Agency and German Technical Cooperation

EcoSan Promotion Project, Kenya

NATURAL ENVIRONMENT

BUILT ENVIRONMENT

EXPENSE Governance

AEROSAN sustainable sanitation Pvt. Lid. , Canada

TIME Level

Usage

Maintainance

Scale

124

Off-grid Toilets

Comparative Classification

Selection by

EXPENSE

Installation cost 1 a. Cost may vary due to different material usage and variation in character of the ground b. Price can deviate due to additional upgrades of the toilet system c. Prices may vary due to competitive landscape of the product in market

For the selection of a sanitation system, price is an important determining factor. Sometimes the system that fits better into a particular context doesn't match with the affordable one. Two investments need to be considered here: Firstly, the cost of the system itself, which includes the price of the required machinery and the installation on site (with the necessary preparatory works, if any). Secondly, the cost of maintenance incurred throughout the whole life of the system; this cost can be balanced with the commercialisation of the outputs in some of the systems.

125

For the determination of the installation cost, a unit toilet has been considered across the systems to easily compare the costs. This decision brought some difficulties due to the fact that some of the systems require infrastructural works, which would make the installation of only one unit extremely expensive (these situations have been endnoted in the chart for consideration). In general, the cost of the systems can’t be accurately estimated due mostly to the fact that installation costs may differ depending on the contextual conditions. The range also varies from one system to another, mainly based on the respective price of installation in the total cost. In terms of the determination of maintenance cost, this information wasn’t available in most of the cases. Regarding this cost, it needs to be considered that most of the cases produce some outputs which have an economic value: organic fertilisers, gas, and electricity are subproducts of waste treatment that would help to finance maintenance costs (information about outputs collected in each system is available in the Efficiency chart which follows).

Fluctuation in prices might occur due to the material coﬆs, labour coﬆs and transportation in all cases.

PRICE PER TOILET UNIT

$100,000 $70,000 $50,000 $25,000 $8,000 $6,500 $5,000 $3,500

126

$2,000 $1,800 $1,600 $1,400 $1,200

$1,000 $800 $600 $400 $200

USER Profile

Agents

Cost

Efficiency

Location

Status

NATURAL ENVIRONMENT

BUILT ENVIRONMENT

EXPENSE Governance

Use

Site

Climate

TECHNOLOGY Impact

Implement

Type

TIME Level

Usage

Maintainance

Scale

Off-grid Toilets

Comparative Classification

Selection by

EXPENSE Efficiency 1

The efficiency of a system refers to the relation between the inputs needed and the outputs produced. The higher the outputs in comparison with the inputs, the higher the efficiency.

As the majority of the off-grid case studies selected produce some valuable outputs (fresh or grey water, organic fertiliser, gas or electricity), the efficiency of the systems might be a factor to consider in the decision-making process.

In the chart below, comparatively displayed:

these

outputs

are

For all systems have been considered 5 people per household and a waste production per person per day of 130 to 520 gr of solid faecal waste and 2 L of urine. The outputs listed in the chart are per household. Input = Output = Secondary output = Require Further Treatment = SALT

Worm 1Kg

Natural Disinfectant

Coconut Fibre

Black soldier flies

Drying Agent

10 Kg

Drying Agent

Carbon Dioxide

Biogas

140L/ Day 0.5K/ Day

Wormy Compost

Biogas

Fertilizer

Liquid Fertilizer

Fertilizer

Electricity

Liquid Fertilizer

2.7L/ Day

Animal Food

Biochar

160L Water

Flush 10L Water

1-1.5L/ Use

Flush 60L Water

Flush

(Sawdust)

127

Bacteria Psychrophilic

Table Salt

(Ashes)

Liquid Fertilizer

10L/ Day

Fertiliser

15L/ Day

Fertiliser

0.5K/ Day

Electricity 2.577KW/h

4KW/h

Water

Liquid Fertilizer 75L/ Day

Methane

1.6K/ Day

Clear Water

8L/ Day

35L/ Day

Methane 21L/ Day

Water

5L/ Day

Water

5.5L/ Day

Ashes

Electricity

Profile

BUILT ENVIRONMENT

EXPENSE Governance

Agents

Cost

Efficiency

Location

Status

Solid Waste

NATURAL ENVIRONMENT Use

Site

Climate

Liquid Waste

450W/ Day

Solid Waste

USER

Water

3.4L/ Day

Methane

Supernatant

Slurry

Electricity

TECHNOLOGY Impact

Implement

Type

TIME Level

Usage

Maintainance

Scale

128

Off-grid Toilets

Comparative Classification

Selection by

BUILT ENVIRONMENT

These location conditions determine the selection of the off-grid sanitation system when needed. Some of them are more suitable in particular locations, as shown in this chart:

Location

Unsafe sanitation practices occur in all possible locations: urban, sub-urban, ex-urban, rural and remote. These locations have particular characteristics concerning urban fabrics, services infrastructures (water, electricity, sewage and internet), mobility networks, public facilities, and community attributes.

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Urban location refers to the most consolidated part of the city, characterised by a higher density of people and a tighter and taller urban fabric hosting mixed-used programmes. In these locations, communities have a strong identity and bonding, usually developed through several generations. Public transportation is widely available in different modes, and infrastructures and public facilities are usually fully consolidated and well distributed.

Sub-urban location refers to a more recent peripheral growth of cities characterised by flat homogeneous residential fabrics. Mostly developed from the mid-20th century, the identities of inhabitant communities are usually weak. In these locations, infrastructures are typically completed, but public transportation is limited, with public facilities available in a dispersed way. Ex-urban location describes the dissolution of the urban condition. This part could be partially unplanned or in a development phase, with an uneven mixture of building forms and uses. Industrial land and heavy infrastructures (such as airports or highways) coexist with newly-built and isolated residential developments. The sense of community is often nonexistent or very weak,

and public transportation and public facilities are scarce. Rural location describes small villages or towns surrounded by rural land and mostly based on a primary-sector economy. Rural fabrics are usually compact, hosting small services and public facilities in them. The rural population has a strong sense of community developed throughout generations. Infrastructures have usually been fully developed. Public transportation is nonexistent or poor, with generally quite limited access to interurban transport.

REMOTE

RURAL

Remote location refers to individual residential constructions surrounded by natural environments. There is nothing related to the public sphere in this locations: sense of community, infrastructural services, facilities or transport are all absent.

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EX-URBAN

The characteristics of this locations are summarised in this chart:

SUB-URBAN

COMMUNITY

INFRASTRUCTURES

PUBLIC FACILITIES

URBAN

SUB-URBAN

EX-URBAN

RURAL

REMOTE

Strong

Medium

Weak

Very strong

Non-existant

Completed

Under developed

Completed

Poor or Non-existant

Diverse and well distributed

Specific and well distributed

Uncompleted or non-existant

Small and well distributed

Non-existant

Rich

Medium or poor

Poor or non-existant

Locally poor and limited interurban

Poorly connected

(High provision)

MOBILITY NETWORKS

USER Profile

(Low provision)

Agents

Cost

Efficiency

Location

Status

a. Need space (not for Urban/Suburban) b. It is a cluster, serving a community (no suitable for places with weak communities--Urban/Suburban/Remote) c. Highly mechanised, not suitable for places with limited accessibility (Rural/Remote) d. Infiltrates into the ground, so needs land (not suitable for urban), and can create unaware contamination (not suitable for remote/natural sites) e. Needs accessibility to a treatment plant and requires minimum-size communities (not suitable for places with remote locations) f. Big infrastructure which requires space (not suitable for dense fabrics). It needs a minimum number of users (not appropriate for remote conditions) and sense of community (not for ex-urban) g. Requires human cooperation, it needs a well-established community (not suitable for Ex-urban/Remote)

NATURAL ENVIRONMENT

BUILT ENVIRONMENT

EXPENSE Governance

URBAN

Use

Site

Climate

TECHNOLOGY Impact

Implement

Type

TIME Level

Usage

Maintainance

Scale

Off-grid Toilets

Comparative Classification

Selection by

BUILT ENVIRONMENT

These differences in status can make some of the selected case studies more suitable than others. Systems requiring a significant investment could be expected in formal settlements, but they wouldn’t occur in squatter settlements. Informal settlements and slums could favour highly efficient systems (which means a bigger proportion of profitable outputs) or be willing to promote bottom-up processes. Depending on

Status

The legal status of human settlements is essential when planning infrastructural development as they can limit construction, maintenance, and improvement. Four statuses need to be differentiated: Formal status defines the settlements formally agreed and planned. The different infrastructural facilities are usually coordinated, updated and maintained.

131

Slum status, contrary to the common use of the word, is a settlement resulting from degradation, usually from a formal part of the city. Originated in England, the term referred to places where impoverished people were living in proximity to the wealthy ones. Slum (“back room” in British slang) described the back alleys of the accommo-

dated houses, usually part of the same urban fabric but more densely inhabited and deteriorated over time. In a slum, infrastructure is generally managed by public authorities who could be neglecting these areas, letting them decay. Some of the settlements we commonly refer to as slums are not so because they are involved in bottom-up improvement processes. Squatter status is assigned to places either occupied or built against the legal frame (usually both), and it can take place in all locations and under the shape of formal or informal fabrics. A building occupied by unauthorised inhabitants in a formal part of the city is a squatter settlement built illegally on lands or under building forms or uses that are not allowed. Some infrastructural services (such as water or electricity) could be nonexistent or illegally taken from the surround-

ings. Other essential services, such as sewage, could be unsafely built and managed by the inhabitants. Usually, investment is nonexistent or poor due to the constant threat of eviction.

the perspective, the conditions for these statuses point to similar or different requirements: formal and informal statuses lie in the two extremes of the legal definition, but both share an interest in maintaining and improving the infrastructure. These are reflected in the chart below.

b,f

Informal status refers to places informally built under an unclear definition of illegality. All cities were informal settlements before the urban-planning era. The term relates nowadays to self-built settlements on unplanned or unowned land or under policies where occupation is the first step to land tenure. In these cases, infrastructural services are self-built, and very limited or nonexistent. The settlement usually exhibits a slow-pace process of improvement as it can be seen as a path to tenure.

SLUM

a,f

e,h

a,f

a,f,h

These conditions are summarised in the chart below:

INFORMAL

FORMAL

LEGAL FRAME

SLUM

LEGAL

SQUATTER

INFORMAL

ILLEGAL

UNDEFINED

a,c,d,f

b,c,d,i

b,c

a,f,h

d,f

b,c,g

b,c,d

b,c,i

b,i

FORMAL b,e,f

SQUATTER INFRASTRUCTURES DEVELOPMENT

TIME EVOLUTION

COMPLETED/ MAINTAINED

COMPLETED/ UN-MAINTAINED

UPDATED

NEGLECTION

USER Profile

SELF-COMPLETED

RESISTANCE

SELF-PLANNED SELF-BUILT

SLOW-PACE IMPROVEMENT

Agents

Cost

NATURAL ENVIRONMENT

BUILT ENVIRONMENT

EXPENSE Governance

a. Requires land (Informal/Slums) b. Compact and portable (Formal/Informal/Squatters) c. Unaffordable (Formal) d. Shared infrastructure serving big communities (Formal/Informal) e. Affordable (Informal/Slums/Squatter) f. Low maintenance (Informal/Slum/Squatter) g. Promotes circular economy (informal/slum) h. High desludging period (Informal/Slum) i. Delicate maintenance (Formal)

Efficiency

Location

Status

Use

Site

Climate

TECHNOLOGY Impact

Implement

Type

TIME Level

Usage

Maintainance

Scale

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Off-grid Toilets

Comparative Classification

Selection by

BUILT ENVIRONMENT

Low

Use

Medium

(below 10 users)

(10-50 users)

High

X-High

(50-500 users)

Even when the necessity of off-grid sanitation systems lies mostly in residential uses (generally in informal settlements and squatter constructions), they also can be used in other programmes due to the temporary character of the use or its remote location.

(over 500 users)

Capacity

NUMBER OF TOILETS NEEDED DEPENDING ON USE :

Capacity

Simultaniety

Some cities deploy public off-grid sanitation systems during festivals or in temporary public facilities or events (such as vaccination centres, temporary hospitals or temporary exhibitions). Some buildings or public facilities located away from the urban cores need off-grid sanitation systems due to the lack of sewage infrastructures close by (such as farms, natural visitor centres, summer camps, or observatories).

Inclusiveness

Three factors could affect the selection of the proper off-grid sanitation system: user suitability, capacity, and simultaneity.

Users A unit for more than that

Home

Low

Users A unit per additional 10 users.

500

Users A unit per additional 500 users.

Shops and shopping malls (over 1000 m2)

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Low

Users

200 A unit per additional 70 users

60-120

Restaurants Assembly Buildings with concentrated activity time (theater,cinema, auditorium, sport stadiums...)

Users A unit per additional 100 users

Mandatory for Physically disable people and nappy changing

f,g

Mandatory for Physically disable people

Medium

Users A unit per additional 20 users; up to 500

Medium

High

Mandatory for Physically disable people Special facilities for staff over 25 seats

Profile

Agents

a,c

c,d

b,c

Regarding the capacity, some off-grid systems are unsuitable for intense use due to their holding tanks' fixed capacity or the time the applied technology needs to process the waste. Logically, public uses would need more significant capacity than private ones. Concerning simultaneity, some of these systems are not compatible with high-simultaneity situations when intense use is required. Simultaneity affects the number of units to install: with a similar number of users, scheduled activities (with concentrated periods of activity time and intervals, such as a theatre or a cinema) may need a higher number of units, a system able to be operated quickly and a process able to digest sudden discharge.

Users A unit per additional 30 users; up to 100 A unit per 50, afterwards

Medium

Cost

j,m

j,k

m,j,l

l,m

j,k

The recommendation charts on the left compile these conditions.

j Specifically referring to four exclusive conditions: age, gender, physical impairment and cultural education:

Mandatory for Physically disable people l,m Exclusive (3-4 exclusive conditions)

Location

Status

j,k

Semi-Exclusive (2 or more exclusive conditions)

Semi-inclusive (1 exclusive conditions)

NATURAL ENVIRONMENT

BUILT ENVIRONMENT Efficiency

m,j,l

Mandatory for Physically disable people

EXPENSE Governance

b,c

Inclusiveness

These data may differ depending on local or regional regulations. The figures shown here refer to the British Standard, BS 6465, part 1 (2006). In cases for male users when a differentiations is made between the provision for urinals and WCs, the biggest provision have been taken as the off-grid case studies presented has not diffentiated urinal units.

USER

Users A unit per additional 30 users; up to 120

Assembly Buildings without concentrated activity time (museums, exhibition centres, libraries...)

A unit per additional 25 users; up to 200

Users A unit per additional 100 users

Users A unit per additional 50 users

Users

Up to

Leisure (pubs, bars, nightclubs, discotheques...)

Low

(50-500)

Simultaniety

Mandatory for Physically disable people

100

Users A unit per additional 200 users.

In terms of user suitability, some case studies wouldn’t be suitable in programmes where most users follow a similar profile. For instance, systems that require complicated operations won’t be viable for a primary school or systems that need to be raised wouldn’t be suitable for facilities or events with the majority of elderly people. For public uses, inclusivity (to suit different kinds of users) is, in most cases, highly recommended or mandatory. It is important to point out here that toilet use is gender sensitive in terms of provision: privacy of spaces is required in conservative cultures, and there are differences in the time of use (men take an average of 35 seconds to use a urinal whilst women take 90 seconds to use a WC). 1

High

(10-50)

(below 10)

Offices

Medium

Use

Site

Climate

j. Gender exclusive k. Elderly/Physically impaired exclusive l. Children exclusive m. Conservative-mind exclusive

Inclusive (No exclusive conditions)

TECHNOLOGY Impact

Implement

Type

a. Based on combustion b. Based on electrochemical process (just liquid waste) c. Wide range of number of users d. Big infrastructure e. Based on infiltration into the soil f. Fixed or small number of users g. Slow digestion h. Small retention tanks i. Long desludging period

TIME Level

Usage

Maintainance

Scale

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Off-grid Toilets

Comparative Classification

Selection by

NATURAL ENVIRONMENT

of water. It is also essential to check the consistency of the different soil layers: ideal conditions in the superficial layers could change in deeper layers and distort the compatibility between the selected case study and the site to implement it. A perfectly porous soil could lie on top of clay, which will retain the liquid and stop filtration unnoticeably.

Site Conditions

Site physical conditions may determine off-grid toilet systems applicability due mainly to the geological conditions, particularly groundwater conditions and soil composition. Regarding groundwater conditions, some case studies require underground works that may be rendered difficult by the presence of high water table levels. Even if these underground works are achievable with the presence of groundwater, it

is not recommended to do so as any leak in the system would produce uncontrolled groundwater contamination. Some other systems, which use filtration to dissipate liquid waste, such as the Two Pit Flush, can’t be implemented without assuring a water table level deep enough to prevent that filtrated waste won't contaminate underground water. For soil composition, a basic geological study of

the strata present under the surface is recommended to get an idea about the different soils’ presence and its consistency across soil’s layers. Some rocky grounds would make systems with important components buried underground, challenging to implement. In other cases, the soil is required to have a specific porosity for absorbing liquid waste, making them incompatible with, for instance, clayey soils which become waterproofed with the presence

These conditions could be comprehended in two specific characteristics: the volume of the underground part (which would make bigger underground parts undesirable with hard soils and high water table levels), and the necessity to infiltrate liquid waste into the ground (making some systems incompatible with waterproof soil layers). A more consistent composition of the different soil layers is preferable in all cases.

Based on these two conditions, the systems can be classified as follows: the higher the underground part, the softer soil required, and the bigger need for infiltration the higher soil porosity required.

OFF-GRID TOILETS SYSTEMS SOIL REQUIREMENTS

High ground Filtration

SOIL CLASSIFICATIONS

135

136 GRAVEL

PERMEABLE

SILT SANDY GRAVEL

SAND

SEMI-PERMEABLE ROCKY SAND

IM-PERMEABLE

No ground Filtration

CLAY

STIFF

HARD

Governance

Agents

Cost

NATURAL ENVIRONMENT

BUILT ENVIRONMENT Efficiency

Location

Big underground works

Considering the systems built as fully accessible (which means that, when possible, any installation under the toilet is built underground)

SPT > 50

EXPENSE

Semi underground

No underground works

SOFT

SPT: 3 TO 50

SPT: 0 TO 3

USER Share

SANDY CLAY

ROCK

[SPT: Standard Penetration Test]

Profile

Medium ground Filtration

SILTY SAND

Status

Use

Site

Climate

TECHNOLOGY Impact

Implement

Type

TIME Level

Usage

Maintainance

Scale

Off-grid Toilets

Comparative Classification

Selection by

CLIMATE CONDITION ACCROSS THE GLOBE

NATURAL ENVIRONMENT Climate

Making human waste an inhospitable place for viruses, bacteria, and parasites is a process which initially takes place by drying and heating the waste. Human waste’s disinfection is closely connected to sustained conditions of high temperature and low humidity. The higher the temperature, the shorter the time is needed for waste purification. Because of this, the climate condition is a significant factor to be considered. The basic functional principle applied by off-grid sanitation systems is centred on creating adverse conditions for the pathogens to survive. Keeping a dry and hot environment could combine with biological and electrochemical methods to accelerate the purification process. Some systems rely mainly on passive approaches ( just to keep the humidity low and the temperature high throughout the necessary time), while other systems display more active ways to eliminate pathogens by implementing complementary processes. The significance of the climate conditions in different systems’ efficiency may differ depending on how much the systems rely on passive or active procedures. If the climate conditions are already dry and hot, creating an adverse atmosphere for the pathogens should be easier. Some designs, such as the Aerosan toilet, take advantage of the wind to accelerate the drying process, a circumstance that needs to be considered when selecting a site.

137

Two sets of data have been collected for the systems’ selection based on weather conditions. On one side, the temperature-dryness-wind requirements aimed by each system (shown in a humidity-temperature Givoni chart). On the other side, it has been mapped where extreme temperature, dryness and winds can be found worldwide.

100% 80%

138

60%

The proximity between the aimed conditions and the existing natural ones would increase the efficiency of the systems, pointing out the adequacy of one with the other.

40% E

Tropical Climate Continental Climate Arid Climate

20%

Polar Climate

Temperate Climate F

-5°C

5°C

0°C

10°C

20°C

25°C

Profile

30°C

35°C

40°C

Agents

Cost

High Wind Power Density 3 ( 450-1300< W/m2 )

Arid and Hyper-Arid 4 ( 20% - 40% )

45°C

Neutral

50°C

Neutral

* Most of the coastal areas are considered as high wind power density area.

NATURAL ENVIRONMENT

BUILT ENVIRONMENT

EXPENSE Governance

High Temperature 2 ( >25°C )

Givoni Chart , °C

USER

General footnote for all: It has been defined hot temperatures over 30 degrees and neutral humidity between 30 to 60%

Human Comfort Zone

15°C

High Solar Thermal Energy 1 ( 2201-2800 kWh/m2/y )

Efficiency

Location

Status

Use

Site

Climate

TECHNOLOGY Impact

Implement

Type

TIME Level

Usage

Maintainance

Scale

Off-grid Toilets

Comparative Classification

Selection Selectionbyby

NATURAL NATURALENVIRONMENT ENVIRONMENT

Embodied Carbon Embodied CarbonFootprint Footprintofofdifferent different 2 materials CO₂/Kg ) ) ( Kg CO₂/Kg materials (2 Kg

Impact Impact

Systems SystemsSelf-sufficiency Self-sufficiency

Systems SystemsPollution Pollution

( Air, Land, Odor and Sound ) ) ( Air, Land, Odor and Sound

SOLAR PANEL SOLAR PANEL (PER MW-h) (PER MW-h)

Waste Release On-site (ROS) Waste Release On-site (ROS) Waste Treated Off-site (TOF) Waste Treated Off-site (TOF)

AIR AIR POLLUTION POLLUTION

25.80 25.80

PVC PIPE PVC PIPE

139

ALUMINIUM ALUMINIUM (33% RECYCLED) (33% RECYCLED)

8.24 8.24

HiH ghig h

STAINLESS STEEL STAINLESS STEEL

6.15 6.15

MM ede iudm ium

PLASTIC PLASTIC

6.06.0

COPPER COPPER (37% RECYCLED) (37% RECYCLED)

2.60 2.60

Slurry Slurry (very high infection) (very high infection)

LoLw ow

LAND LAND POLLUTION POLLUTION

Once the systems operate, pollution is is produced atat Once the systems operate, pollution produced different levels that also need toto bebe considered. The different levels that also need considered. The first firstone oneis isrelated relatedtotogreenhouse greenhousegas gasemissions. emissions. OnOnthe theone onehand, hand,some someofofthe thesystems systemsproduce produce emissions emissionsofofone oneorormore moreout outthese thesegases: gases:carbon carbon dioxide (CO ), methane (CH ), chloroflurocarbons 2 ), methane (CH 4 ), chloroflurocarbons dioxide (CO 2 4 (CFCS) or water vapour; and these quantities (CFCS) or water vapour; and these quantitiesneed need totobebeevaluated. evaluated.OnOnthe theother otherhand, hand,most mostofofthe the analysed analysedsystems systemsproduce produceorganic organicfertilisers, fertilisers,which which would wouldpositively positivelyimpact impactthe thecontext contextbybyreducing reducing Nitrous O) emissions, a greenhouse gas 2 O) emissions, a greenhouse gas NitrousOxide Oxide(N(N 2 released by artificial fertilisers. Secondly, the released by artificial fertilisers. Secondly, therisk riskofof soil soilpollution pollutionthat thatsome somesystems systems(particularly (particularlythe the ones using chemical products) present needs toto bebe ones using chemical products) present needs considered. considered.Some Someofofthe thesystems systemscould couldalso also produce produceodour odourpollution pollutionin inthe thesurroundings, surroundings, making makingthe thesite siteselection selectionvery verysensitive. sensitive.Lastly, Lastly,the the systems systemswhich whichinclude includesome somemechanical mechanicaldevices devices would be susceptible to producing sound would be susceptible to producing sound pollution and that also needs toto bebe considered. pollution and that also needs considered.

ODOR ODOR POLLUTION POLLUTION

Similarly Similarlytotoany anyother otherimplementation implementationdecision decision nowadays, the knowledge ofof each system's embodnowadays, the knowledge each system's embodied iedcarbon carbonfootprint footprintcould couldbebea adetermining determining factor. factor.The Thematerials materialsand andtechnologies technologiesdeployed deployedtoto produce these sanitation systems make an accountproduce these sanitation systems make an accountable ableemission emissionofofgreenhouse-effect greenhouse-effectgases gasesthat thathad had already impacted the natural environment already impacted the natural environmentbefore before they theybecame becameoperative. operative.The Theembodied embodiedcarbon carbon footprint counts forfor the emissions produced during footprint counts the emissions produced during the thewhole wholeprocess processofofbuilding buildingand anddismantling dismantling them: them:extraction extractionofofraw rawmaterials, materials,processing, processing, transport, transport,manufacturing, manufacturing,building buildingand andrecycling recycling (so, everything except during their operation time). (so, everything except during their operation time). A Alistlistofofthe embodied carbon in some the embodied carbon in someofofthe the materials materialsused usedin inthe thecase casestudies studiescan canbebeseen seenonon the right side. the right side.

Solid Waste Solid Waste (highest infection) (highest infection)

ExEt xretrme m elye lhy ighi hgh

24.40 24.40

CERAMIC CERAMIC (SANITARY WARE) (SANITARY WARE)

1.51 1.51

Supernatant Supernatant (high infection) (high infection)

STEEL STEEL (AVG. RECYCLED) (AVG. RECYCLED)

140

1.37 1.37

GLUE LAMINATED TIMBER GLUE LAMINATED TIMBER

0.87 0.87

TIMBER TIMBER

0.72 0.72

SOURCES SOURCESOF OFGREEN GREENHOUSE HOUSEGAS GASEMISSIONS EMISSIONS 1 1

Greenhouse-effect factor (relative to to COCO ) ) 2 Greenhouse-effect factor (relative 2 Relative Abundance (relative to to COCO ) ) 2 Relative Abundance (relative

BATTERY BATTERY (PER 1.5Wh) (PER 1.5Wh)

Greenhouse-effect factor combined with Abundance (relative to to COCO ) ) 2 Greenhouse-effect factor combined with Abundance (relative 2

(Water Vapour) (Water Vapour) 0.10.1 2.77 2.77 -72.3% -72.3% (Carbon Dioxide) (Carbon Dioxide) 1 1 1 1 0%0%

(Methane) (Methane) 3030 0.047 0.047 +1.4% +1.4%

H2HO O 2

CO2 CO2

N2No o 2

Share Share

(Chloroflurocarbons) (Chloroflurocarbons) 20,000 20,000 0.00027 0.00027 +0.022% +0.022%

Governance Governance Governance Governance

Agents Agents

(Nitrous Oxide) (Nitrous Oxide) 160 160 0.0083 0.0083 +0.2% +0.2%

Cost Cost

Lastly, Lastly,some someofofthe thesystems systemsare arenot not self-sufficient self-sufficientdelivering deliveringsafe-managesafe-manageable able waste. waste. This This means means that that these these systems release untreated waste into the systems release untreated waste into the environment or oblige users to manage environment or oblige users to manage the necessity of further processes off-site the necessity of further processes off-site toto disinfect the waste. disinfect the waste.

BRICK BRICK 0.24 0.24

CONCRETE CONCRETE 0.13 0.13

Efficiency Efficiency

Location Location

Liquid Waste Liquid Waste (low infection) (low infection)

SELF-SUFFICIENT SELF-SUFFICIENTSYSTEMS SYSTEMS Treating allall the waste On-site Treating the waste On-site

The type and quantity ofof untreated waste The type and quantity untreated waste is isa ameasurement measurementofofthe thesystems’ systems’ self-sufficiency and its possible impact self-sufficiency and its possible impact into the environment. into the environment. NATURAL NATURAL ENVIRONMENT ENVIRONMENT

BUILT BUILT ENVIRONMENT ENVIRONMENT

EXPENSE EXPENSE

USER USER Profile Profile

SOUND SOUND POLLUTION POLLUTION

0.30.3 CFCS CFCS

CH CH 4 4

Anal-cleansig water Anal-cleansig water (moderate infection) (moderate infection)

Status Status

Use Use

Site Site

Climate Climate

SYSTEMS SYSTEMS RELEASING RELEASING WASTE WASTEON-SITE ON-SITE (ROS) (ROS)

TECHNOLOGY TECHNOLOGY Impact Impact Impact Impact

Implement Implement

Type Type

SYSTEMS SYSTEMS TREATING TREATING WASTE WASTEOFF-SITE OFF-SITE (TOF) (TOF)

TIME TIME Level Level

Usage Usage

Maintainance Maintainance

Scale Scale

Off-grid Toilets

Comparative Classification

Selection by

LEVEL OF IMPLEMENTATION AND PLACE

TECHNOLOGY

Implementation and Development

Southern Asia

(284,263 units)

Southern Africa

(35,200 units)

Eastern Africa

(22,032 units)

Norhtern Africa

(14,668 units)

Western Africa

The off-grid sanitation systems are not for exclusive implementation in informal settlements; however, until now, most applications are related to informality (as seen in the world map). Some factors could increase the demand for off-grid systems in the future in urban and rural environments.

141

In urban settings, the increasing growth in size and complexity of cities could require the co-existence of on-grid and off-grid sanitation systems in the near future, as it is already happening with other infrastructures. Some parts of the city could be growing too dispersed to make the extension of the existing sanitation infrastructure cost-effective. Some other parts, could be degrowing at such a fast pace, and could come to a point to make adequate maintenance of infrastructure financially unaffordable (as already happened in some cities, such as Detroit). In rural settings, communities are deeply rooted into a circular-economy mentality which welcomes off-grid systems. Most off-grid systems produce natural fertilisers that can be used directly on-site, with obvious economic and environmental benefits in a rural setting. The small scale of rural communities could also make big infrastructure unaffordable to build and maintain. It needs to be considered as well that dispersion could encourage the implementation of off-grid systems: depending on the size of land exploitations, sometimes rural constructions are pretty dispersed. Four different phases of development need to be differentiated here. These phases represent a sequence as follows: prototype, field-test, implementation and assessment and may include some looping back, particularly from field-test phase to prototype and from assessment to implementation.

The field-test phase implies an on-site application of the system open to users in real contextual conditions unreplicable in a laboratory. Feedback from this phase could need to go back to the prototype adjustments and laboratory-test phase.

245,000

CENTRAL AMERICA

units

All the systems collected in this book have been implemented on different scales, except for Biochar, Nano Membrane, and RTI International, which are in the laboratory-test phase.

SOUTHERN ASIA India 140 units

WESTERN AFRICA

51,195

India 13,540 units

NORHTERN AFRICA

EASTERN AFRICA

units

SOUTH-EASTERN ASIA

Nepal 16 units

17,200 units PROTOTYPE AND LABORATORY TEST

Design completed, one unit built and tested in laboratory.

ASSESMENT

FIELD TEST

SOUTH AMERICA

17,000

IMPLEMENTATION

Compilation and evaluation of users' feedback and definition of improvements if any.

Numerous units construction and installation in different context conditions and open to users

Southern Africa 35,000 units Northern Africa 14,668 units

2005

Agents

Cost

Costa Rica 2 units

2007

Kenya 2 units

2010

Location

Status

Use

Site

Climate

Kenya 1,134 units

India 95 units

Liberia, Ethiopia, Myanmar and Uganda 900 units

Bangladesh 2,176 units

India 4,500 units

2015

2016

2017

2018

2019

2020

2021

2022

Implement

Thailand ? units India ? units

11, 12

7 5

Type

Kenya 3,691 units

Bangladesh 1,387 units

TECHNOLOGY Impact

United States 24 units Ecuador 163 units

NATURAL ENVIRONMENT

BUILT ENVIRONMENT Efficiency

India 245,000 units

Senegal 6 units Cambodia 3 units

Ghana 16 units Benin 10 units South Africa 200 units Vietnam 20 units Mongolia 10 units India 9 units

India 17,000 units

Kenya 1 unit (5 toilet)

Uganda 17,200 units

Cambodia 403 units

2 4

TOP 5 SYSTEMS THAT HAS BEEN IMPLEMENTED THE MOST WORLDWIDE

142

8, 9, 10

units

India On Test

SOUTHERN AFRICA

13,540

One unit installed on real-context conditions and open to users.

23 18

Ghana 700 units

units

EXPENSE Governance

20, 21, 22

NORTHERN ASIA

The assessment phase implies that feedback has been compiled and evaluated from different implementations, and conclusions have been obtained to address maladjustments, if any. This phase could require going back to implementation or even field tests to address the feedback.

USER Share

NORTH AMERICA

The implementation phase means the numerous construction and installation procedures of the system in real and diverse conditions of use.

The prototype phase means that at least one system unit has been built and tested in the laboratory.

Profile

(732 units)

India ? units Kenya ? units

India ? units

TIME Level

Usage

Maintainance

Scale

Off-grid Toilets

Comparative Classification

Selection by

TECHNOLOGY Type

Thermal

Biological

Bio-Electro-Chemical

Slurry

Regarding the technological type, the first differentiation to make is related to passive and active technological approaches. Passive approaches are the ones which don’t need any artificial input. The systems under this category only use the natural resources available in the context (such as solar exposition or air flow) to accelerate the disinfection process. No energy, chemical or electro-mechanical components are added to speed up the process. These almost ‘no-technology’ systems are usually slow but very accessible and sustainable. Depending on the contextual conditions, they can be quite efficient due to the lack of inputs.

143

Mechanical Separator

Sedimentation

Supernatant

Active approaches use the addition of energy, biological, thermal, electrical or chemical devices, or a combination of them, to accelerate the disinfection process of human waste.

Supernatant

In the selected case studies and under these two different approaches, three different technologies are used in their core process of human waste disinfection, namely:

Solid Product

Heat (Evaporation)

Filtration (Plant Based)

CH4 Methane

Dilution / Retention Time

Aerobic

144 Bacteria

CO2 Carbon dioxide

Condensation

Filteration

Electrolysis Reedbed/Wetland

Re-use

Cost

Efficiency

Location

Status

Treated Water

NATURAL ENVIRONMENT

BUILT ENVIRONMENT

EXPENSE Agents

Treated Water

Plant

Use

Site

Climate

TECHNOLOGY Impact

Re-use

Activated Carbon

Plant

Treated Water

Treatment Plant

Partially Treated Water

Treatment Plant

Ashes

USER

Electrolysis

Fertiliser

Treatment Plant Biochar

Bio-Electro-chemical technology is named after the processes combining biological, electrical and chemical technologies. These systems would be using bacteria or worms as part of the process, combined with electrolysis and addition of chemical catalyzers in the process of disinfection. These processes are highly active in their approach.

Governance

Anaerobic

Solid Product

Heat

Biological technology uses organisms to digest human waste aerobically or anaerobically to disinfect it. Anaerobic digestion can take place passively by using the same bacteria included naturally in the human waste. Some systems would require a more active approach through adding specific bacteria or worms for accelerating aerobic or anaerobic digestions.

Supernatant

Dilution / Retention Time

Filtrating (in ground)

Thermal technology uses heat energy to disinfect human waste. Some systems use passive thermal technology, where solar energy is captured and used to heat the waste. Other systems entirely use an active approach as heat energy is produced by several ways, such as; by using electricity to power a coil, by circulating hot water.

Profile

Solid Product

Implement

Type

Plant

TIME Level

Usage

Maintainance

Scale

Off-grid Toilets

Comparative Classification

Selection by

TECHNOLOGY Level

Specialised or High-Tech

The off-grid sanitation systems compiled in this book may require different levels of technological knowledge. These levels are necessary during the three stages of the systems development: fabrication, implementation, and maintenance. Three technological levels will be differentiated for this purpose: -Specialised or High-Tech level means the necessity of highly trained people and/or equipment.

145

-Transferable or Medium-Tech level means that the necessary knowledge or equipment can be easily transferred to untrained people.

easily implemented or maintained, with or without training for these processes (transferable and DIY technologies, respectively).

-Do-It-Yourself (DIY) or Low-Tech level means that no specific knowledge is needed or the knowledge needed can be easily obtained by untrained individuals.

The chart below displays these conditions.

Transferable or Medium-Tech

Do-It-Yourself (DIY) or Low-Tech

Different technological levels could be necessary for the various stages of the systems’ development. Some systems could need high-technology skills for their fabrication, but they could be

146

MAINTENANCE

IMPLEMENTATION

FABRICATION

USER Profile

Governance

Agents

Cost

NATURAL ENVIRONMENT

BUILT ENVIRONMENT

EXPENSE Efficiency

Location

Status

Use

Site

Climate

TECHNOLOGY Impact

Implement

Type

TIME Level

Usage

Maintainance

Scale

Off-grid Toilets

Comparative Classification

Selection by

TIME

Use term

Off-sanitation systems could be implemented to cover necessities in different terms.

facilities covering short-term, medium-term or long-term necessities, respectively.

Buildings could be definitive (long-term use) or temporary in for different periods of time (medium and short-term). A campsite, a vaccination centre or a remote house could be examples of programmes needing sanitation

The length of the use could adapt better to some off-grid sanitation systems than others. Shortand medium-term usage could be discouraged when installation works are very costly. Systems with high portability, intended to be easily

moved, could be more suitable for shorter terms than highly customisable systems designed to accommodate user particularities. Systems which promote human cooperation need longer terms to build community relations.

a. Portability (short/medium)--depending on how portable b. Expensive (long/medium)--depending of how expensive c. Big Infrastructure/Wetland (long) d. Need human cooperation/Business model (long)

COMPACT BIG INFRASTRUCTURE

HUMAN COOPERATION AND OFF-SITE TREATMENT

WET LAND

PORTABLE CONTAINER

NOT VERY COMPACT

UNDERGROUND INFRUSTRUCTURE

LONG TERM

147

148

MID TERM

SHORT TERM a,b

a,c

USER Profile

a,c

Agents

Cost

a,b

a,c

Efficiency

Location

Status

a,b

NATURAL ENVIRONMENT

BUILT ENVIRONMENT

EXPENSE Governance

a,b,c

Use

Site

Climate

TECHNOLOGY Impact

Implement

Type

TIME Level

Usage

Maintainance

Scale

Off-grid Toilets

Comparative Classification

TIME

Maintenance and obsolescence

Frequency

Selection by Maintenance Desludging Refilling

once

a year

a week

every 2-3

twice

a year

once

a week

Maintenance

a week

every 3

low

once

a year

5-7

months

once

days

12-15

a year

years

every 1-2

months

once

years

Maintenance

free

a year

Years

This situation may vary depending on toilets' ownership. Toilets owned directly by the user communities tend to be better maintained than the ones owned by public entities. Communities are aware of the investment represented by the toilet and the importance of keeping them well maintained for comfortable use. Two other important factors need to be considered.

149

On the one hand, the frequency of maintenance needs to be established. Some systems may require weekly attention to keep them functional, while others will require monthly or yearly maintenance operations. This necessity has consequences in the community because it disrupts the use of the toilet and implies some cost (in money or work) that must be covered. On the other hand, it is essential to consider the skills needed for maintenance operations. If a high level of technical knowledge is required, communities need to delegate maintenance to others who are capable to do the job, a situation that implies community organisation and funds supply to do so. Sometimes, the technical knowledge required could be transferred to community members who are capable to handle for these tasks, or maintenance doesn’t require specific expertise or training at all, so users themselves can easily do it. Off-grid sanitation systems, like any other human construct, are subject to obsolescence. The useful life of a system and its vulnerability depends on several factors, some intrinsic and some extrinsic. The intrinsic factors are mainly the technology deployed and the conditions of use and maintenance. Highly mechanised systems would require more attention in maintenance and could be

more vulnerable to deterioration or decay through the partial failure of some of their components. More the components assembled in a system, more demanding is maintenance and higher the risk of deterioration. Public facilities tend to deteriorate faster than private facilities due to the intensity of use and care conditions. The extrinsic factors are related to the environment, natural and built, where the system has been implemented. Some environmental conditions could be more aggressive for the particular materials used in the different sanitation systems. Metalic components could be subject to faster deterioration in humid environments, and the lifespan of batteries is shortened by hot weather. Once obsolescence arrives, an essential factor to consider is how the process of dismantling will take place and what are the difficulties encountered and the residues produced through this process. This factor could determine the selection of a system, particularly in areas susceptible to residues, such as protected natural environments. Systems built with more natural materials, such as bricks, would produce residues easier to treat than systems using plastic, metal, or batteries. Some systems may impact the environment longer than the system itself, for instance, when the infiltration of waste in the ground generates brownfields. Other toilets could be challenging to dismantle due to the complexity of the artefact and the time needed to disassemble it, reducing the possibility of recycling the small components.

Vulnerability Dismantling Dismantling

USER Profile

Low

Medium

High

Easy

Medium

Difficult

Low

Medium

High

a. Needs to check the auger screw. b. Take out the ash. c. Service company give service by giving new sets. d. Low maintenance. e. Replacement of worms' bed depending on the number of user. f. Sediments need to be collected from the septic tank. g. Refill sawdust (depending on sawdust tank's size). h. Depends on the pit size and geology of the soil. i. Per 5 toilet cubicles, 2 showers and one urinal. j. Needed depending on tank size.

Agents

Cost

Efficiency

Location

Status

NATURAL ENVIRONMENT

BUILT ENVIRONMENT

EXPENSE Governance

150

k. Requires dismantling of hard infrastructure. l. It contains significant proportion of electronic waste.

Life Expectency

As reported by the World Bank, most shared and public toilets fail within a few years of installation because of (often) predictable problems associated with ongoing operations and maintenance.

Use

Site

Climate

Implement

TECHNOLOGY Impact

Type

TIME Level

Usage

Maintainance

Scale

Off-grid Toilets

Comparative Classification

Selection by

TIME

Scalability

e rg

Lastly, some other sanitation systems would propose high flexibility in how each unit is built and how it can be extended, allowing augmented levels of adaptation in response to user’s differences. This approach has been named free scalability. Following this strategy, we can find systems without compatible shared components and close to each other, and these can be quite freely scaled.

w ns

ing

l tr a

le a

te d

ta n

tes I n filt r a

pl ork

MODULAR

TO HUMAN COOPERATION

ero

bic d

TO WETLANDS

tla

it e v e r m i c o m p o

-s off

s ti

qu Re

ire

att

152 ATTACHED

(by co m bu

s ti o

at m

a ste

F u l l t re

This system need in the proximity a vermicomposting plan.

fw to

igestion)

(

of w

TO VERMICOMPOSTING

FREE

12m²

area/unit

a by

Requ

lar

SCALABILITY OF THE CASE STUDIES

et w

f u se ro

u ma

ctu

tr u

f u n it s ber o

ATTACHED

4m²

Nee d h

re :

la du

These systems have a layout containing more than one unit.

These systems have a human network in place as part of the infrastructure needed. The capacity of this network needs to be consider before scaling them. Some of these systems create a business opportunity within the community, and the others need a network for transporting waste to further treatment.

t i n t o t h e g ro u

al c

Par tially

This systems have an infrastructure attached able to attend this quantity of users.

4units

fras

5units

X 2000

Shared in

BY UNITS

area/unit

These systems need a particular dimension of wetlands attached as part of the needed infrastructure.

Agents

Cost

NATURAL ENVIRONMENT

BUILT ENVIRONMENT

EXPENSE Governance

BY PEOPLE

MODULAR

USER Profile

infi

FIXED

M odu

These systems have limitations to grow in proximity due to liquid waste infiltration into the ground. The distance between units depend on the soil characteristics.

X 50

r is

These systems can be freely scale. They don't response to any module or have attached infrastructures to consider. These systems are or can be self-sufficient in treating the waste.

Full treat

Some other systems are attached to necessary pieces of infrastructure that need to be considered for scaling them (attached scalability). This is the case of systems which may require a particular dimension of wetlands attached to the toilet to finish the treatment, or systems that rely on a network of human cooperation. If a system of collection and treatment is in place run by human cooperation, the number of units can't be increased without considering the necessity to increase proportionally the supporting network.

Freshwater

e at

151

Other systems are delivered in modules of units or users (modular scalability). This means that the shared infrastructure has a limited capacity and for increasing it, new modules need to be put in place. For instance, some systems can share a ventilation infrastructure every four units, or some of them could be connected to a processing machinery able to cope with a particular number of users. If new demands appear, it need to be kept in mind that it may require the installation of a new module of users or units. If I need five units, to select a modular system organised in four-units modules would be unpractical.

Self-sufficient

2-10 m

Cl u ste r o f u ni

Off-grid sanitation systems, may have a different approach regarding the evolution of users' necessities and context changes throughout time. Some systems do not contemplate the possibility of modification or extension to the infrastructures differently from the construction of new independent units– an approach named fixed scalability. Systems unsuitable for growing in proximity, such as the ones dispersing the liquid waste by infiltrating it into the ground, will follow this strategy.

O nly an

te d

t er

FREE

trea

FIXED

Efficiency

Location

Status

Use

Site

Climate

TIME

TECHNOLOGY Impact

Implement

Type

Level

Usage

Maintainance

Scale

Off-grid Toilets

Comparative Classification

COMPILATION CHART

153

][

[

Construction cost Per Unit

]

[

Input ↓ Output ↑ RFT (Requires further treatment)

Capacity Simultaniety Inclusiveness

]

[

]

Hardness Permeability

][

[

Liberal, Children/Adults

Shared

Top-Bottom up

Aerosan, Canada

$250

[↓ Coconut fibre] [↑ RFT]

Rural Ex-urban

Slums Informal

Low Medium Semi-Exclusive

Stiff Impermeable

Below 30% Over 30°C Neutral/Windy

Conservative, All ages Women friendly

Shared Communal

Top-Down

DRDO, India

$700 - $1500

[↓ Bacteria] [↑ Treated water, Biogas]

All

Formal

Medium Low Inclusive

Stiff Impermeable

Over 60% 25°C to 35°C Neutral/Windy

Liberal, Adult, Elderly

Communal

Top-down

Climate Foudnation, USA

$ 60,000 to $ 100,000

[↓ Electricity] [↑ Biochar]

Rural

Formal Informal

X-High High Exclusive

Hard Impermeable

All neutral

Liberal, All

Shared

Bottom up

Biofilcom, Ghana

$ 1,000 $ 1,200

[↓ Worm] [↑ Fertilizer, CO2, Grey water]

Rural Ex-urban Sub-urban

Informal

Low Medium Semi Exclusive

Soft Permeable

65-75% 15°C-25°C Neutral/Windy

Conservative, All

Public

Top-Bottom up

Ecosan Promotion Project, Kenya

$ 5700

[↓ Flush water] [↑ Biogas, Fertilizer, RFT]

Rural

Formal

Soft Impermeable

Over 60% 25°C-35°C Neutral/Neutral

Conservative, All

Private

Top-Bottom up

DRDO, India

$ 700

[↑ Treated water, Biogas ]

Slum Informal

Low Low Inclusive

Stiff Semi-Permeable

Liberal, Adult, Elderly Women Frendly

Shared

Top-Bottom up

EAWAG

$ 500

[↓Flush water, Electricity] [↑ Treated water, RFT]

Rural Ex-urban Sub-urban Remote

High High Semi-Inclusive

Urban Rural Sub-urban

Formal Infromal

Low Low Semi-Exclusive

Conservative, Children,Adult Women Friendly

Communal

Top-down

Caltech, USA

$ 1,500.00 to $ 2,000.00

All

Formal

Liberal, Adult, Elderly Women Friendly

Private

Bottom up

Critical Practices LLC, USA

$ 100 - $ 150

[↓ Drying Agent] [↑ Fertilizer, liquid fertilizer]

Rural Ex-urban Remote

Liberal, Adult, Elderly Women Frendly

Private, Shared

Bottom up

SCOPE, India

$ 300

[↓ Drying Agent] [↑ Liquid Fertilizer, Fertilizer]

Liberal, Adult, Elderly

Shared, Communal

Top-Bottom-up

Sanergy, Kenya

$ 100.00 $ 300.00

[↓ Black soldier flies] [↑ Animal food, Biogas and fertilizer]

Conservative, All Women Friendly

Private, Shared

Top-down

Cranfield University, UK

$ 750

[↓ Electricity] [↑ Ashes, Treated water]

Conservative, Children, Adult

Communal

Top-Down

RTI Intl., USA

$ 2500

Conservative, All

Shared

Top-Bottom up

AIT, Thailand

Conservative, All

Shared, Communal

Bottom-up

Conservative, Adult

Public, Communal

Profile

USER

]

Embodied Carbon Pollution (Land, Sound, Odor, Gas) Humidity RFT/ROS (Requires Temperature Sun/Wind Further Treatment/Released On Site)

Low L:None/O:X-High G:None/S:None Slurry/None

[

]

Fabrication Implementation Maintenance

]

Units World wide

Medium Medium Low

[

Use Term

[

]

Maintenance/Desludging/Refilling Life Expectancy Vulnerability/Dismantling/Residue

]

Medium

---/1 Year/--4-8 Years Low/Medium/Medium

Modular

Medium Medium Medium

Medium & Short Term

---/---/--? Low/Difficult/high

Modular

Thermal

High Medium High

Medium & Long term

---/---/? 10 years or more High/Difficult/High

Modular

7,576

Biological

Low Low Low

Long term

---/---/5-7 years 10-20 years Low/Medium/High

Fixed

Low No Pollution Supernatant/None

1 (5 Toilets)

Biological

Medium High High

Long term

---/1 Year/--? high/Easy/low

Modular

Over 60% 25°C to 35°C Neutral

High No Pollution None/None

245,000

Biological

Medium Low Low

Medium & Long

---/---/? 30 Years or less Low/Medium/High

Attached

Stiff Impermeable

Neutral 20°C-25°C Sunny/Neutral

Low No Pollution Liquid and solid waste/None

17,200

Bio-ElectroChemical

High Medium High

Long

---/2 weeks/--7-10 Years Medium/Medium/High

Attached

Medium High Semi-inclusive

Stiff Impermeable

Neutral Neutral Sunny/Neutral

X-high No pollution Solid waste/None

Bio-Electro-Chemical

High Medium High

Short & Medium term

---/2 days/--20 years High/Difficult/High

Attached

Slum Infromal

Low Low Semi Exclusive

Hard/Stiff Impermeable

Below 30% Over 30°C Neutral/Windy

465

Biological

Medium Low Low

Medium term

1 week/---/--5 years or more Medium/Medium/Medium

Free

All

Stiff Semi-Permeable

51,195

Biological

Low Low Low

Short

---/1-1.5 Years/--? Low/Easy/Low

Fixed

Rural Urban Sub-urban Ex-urban

Low Low Semi Exclusive

Slums Infromal

High Low Exclusive

Stiff Impermeable

4,825

Biological

Low Low Low

Long Term

---/2-3 Year/--5-6 Years Low/Easy/Low

Attached

Urban Ex-urban Sub-urban

Formal

Low High Semi Exclusive

Hard Impermeable

700

Thermal

High Medium High

Medium & Short term

---/1 Week/3 months 7-14 Years High/Difficult/Medium

Free

[↓ Electricity] [↑ Ashes, Treated water]

Urban Sub-urban Ex-urban

Formal

Medium High Semi Exclusive

Hard Impermeable

Neutral Neutral Sunny/Neutral

On Test

Thermal

High Medium High

Long & Medium term

---/---/--10-13 Years High/Difficult/High

Modular

$ 2,580

[↓ Electricity] [↑ Liquid Fertilizer, CH4]

X-high L:None/O:None/ G:X-high/S:High None/None

Rural Ex-urban Remote

Slum Informal

Low Medium Inclusive

Stiff Semi-permeaable

Neutral Over 30°C Sunny/Neutral

Medium No Pollution None / None

Thermal

Medium Medium Medium

Sulabh Intl., India

$ 31 - $ 275

[↓ Flush water, [Biogas,↑ Fertilizer]

Rural Ex-urban

Slum Informal

Soft Permeable

Over 60% 25°C-35°C Neutral/Neutral

498

Biological

Medium Medium Low

Long term

---/1-2 Years/--? Low/Difficult/High

Fixed

Top-Bottom up

IIT, India

$ 1,625

[↓Natural disinfectant] [↑ Fertilizer, Treated water]

Urban Sub-urban Rural Ex-urban

Low Medium Semi Exclusive

Low L:X-high/O:None/ G:None/S:None None/Supernatant

Medium & Long

Formal Informal Slums

High High Semi-Exclusive

Stiff Impermeable

40-50% 18°C-25°C Neutral/Neutral

X-high No Pollution Solid waste/None

17,000

Biological

Medium Medium Medium

Short term

---/1 Year/--25-30 years Low/Easy/Low

Attached

Governance

Agents

Cost

Efficiency

Location

Status

Use

Site

Climate

Impact

Implement

Type

Level

Usage

Maintainance

Scale

EXPENSE

[↓Table salt, Flush water, Electricity] [↑Liquid Fertilizer, RFT]

BUILT ENVIRONMENT

High L:None/O:None G:High/S:None None/None

Medium L:None/O:None/ G:None/S:X-High Liquid waste/None Low L:X-high/O:high/ G:High/S:None None/None

High L:None/O:X.high/ G:None/S:Medium None/None

High Over 60% L:High/O:High/ 25°C-35°C G:None/S:None Neutral/Windy None/Anal Cleansing Water High 33%-60% L:None/O:High/ 10°C-45°C G:None/S:None Liquid and solid Neutral/Windy waste /None Low L:None/O:None/ All Neutral G:High/S:Medium None/None

NATURAL ENVIRONMENT

Biological

13,540

Biological

TECHNOLOGY

---/1 Year/--10 years or more Medium/Medium/ Medium

TIME

Attached

154

Off-grid Toilets

Comparative Classification

ENDNOTES GENERAL INFORMATION Access to Basic Sanitation 1. World Health Organization. “Sanitation.” Accessed July 27, 2022. https://www.who.int/news-room/fact-sheets/detail/sanitation 2. The World Bank. " People using at least basic sanitation services (% of population)." Accessed November 06, 2022. https://data.worldbank. org/indicator/SH.STA.BASS.ZS?fbclid=IwAR2RRTazCGoBVZYpTp_ c9BpR12Ydbql_y39hRGF1HauDcMDMMYZD2z-X4ig 3. UNICEF Bangladesh. “Billions of people will lack access to safe water, sanitation and hygiene in 2030 unless progress quadruples – warn WHO, UNICEF.” July 01, 2021. https://www.unicef.org/bangladesh/en/ press-releases/billions-people-will-lack-access-safe-water-sanitationand-hygiene-2030-unless?fbclid=IwAR0dolyF7E2G2xCQaoe1JsVSlTco5F huJ3-CfRD1F6wNtbwTvGK6PuvHw6Y

155

4. The World Bank. “Clean water and sanitation.” World Bank. 2017. Atlas of Sustainable Development Goals 2017 : From World Development Indicators. Washington, DC: World Bank. 2017. https:// datatopics.worldbank.org/sdgatlas/archive/2017/SDG-06-clean-waterand-sanitation.html

3. Aggarwal, Shivangi. “Is India really open-defecation-free? Here’s what numbers say.” Down To Earth. July 13, 2021. https:// www.downtoearth.org.in/news/rural-water-and-sanitation/ is-india-really-open-defecation-free-here-s-what-numbers-say77918#:~:text=But%20a%20recent%20joint%20monitoring,India%20 defecates%20in%20the%20open.

14. Humanitarian Information Unit. “World Water Day 2016: HUMANITARIAN INFORMATION UNIT Urban Access to Sanitation.” U.S. Department of State March 18, 2016. https://reliefweb.int/map/world/ world-water-day-2016-urban-access-sanitation-18-march-2016

4. ABC News. “Global Health: Bangladesh.” Accessed October 21, 2022. https://abcnews.go.com/Health/photos/photos-unsafe-water-claimslives-bangladesh-12372642/image-12372835

1. New Humanitarian. "No relief as most Monrovians go without toilets." November 19, 2008. https://www.thenewhumanitarian.org/ news/2008/11/19/no-relief-most-monrovians-go-without-toilets

5. Revkin, Andrew C. “2.6 Billion With No Place to Go (to the Toilet).” Dot Earth. March 20, 2008. https://archive.nytimes.com/dotearth.blogs. nytimes.com/2008/03/20/26-billion-with-no-place-to-go-to-the-toilet/ ?mtrref=undefined&assetType=PAYWALL

2. Foggitt, Ella, Sally Cawood, Barbara Evans and Patricia Acheampong. “Experiences of shared sanitation – towards a better understanding of access, exclusion and ‘toilet mobility’ in low-income urban areas.” Water, Sanitation and Hygiene for Development 9, No.3 (581-590). https://doi.org/10.2166/washdev.2019.025

6. Sinha, Kounteya. “ One toilet for 1,440 people at Dharavi.” Times Of India. November 10, 2006. https://timesofindia.indiatimes.com/india/ one-toilet-for-1440-people-at-dharavi/articleshow/387002.cms 7. Biplob, Pramanik, Dipok Chandra Sarker and Ram Chandra Sarker. “Assessment of Water Supply and Sanitation Facilities for Korail Slum in Dhaka City.” International Journal of Civil & Environmental Engineering IJCEE-IJENS 11, No. 5 (October, 2011): 115-128. https:// www.researchgate.net/publication/282062799_Assessment_of_Water_ Supply_and_Sanitation_Facilities_for_Korail_Slum_in_Dhaka_City 8. “Wash challenges in slum areas of Dhaka city”. Australian Aid, ITN-BUET and Oxfam. Accessed October 21, 2022. https://www. researchgate.net/publication/319348913_WASH_Challenges_in_Slum_ Areas_of_Dhaka_City

5. Geneva: World Health Organization (WHO) and the United Nations Children’s Fund (UNICEF). 2021. “Progress on household drinking water, sanitation and hygiene 2000-2020: five years into the SDGs.”

9. Hendrik, Nombulelo Damba. “South Africa: Fifty Families Share Two Toilets in Taiwan, Khayelitsha.” All Africa. April 26, 2022. https://allafrica. com/stories/202204260226.html

6. United Nations Children’s Fund (UNICEF) and World Health Organization. 2019. "Progress on household drinking water, sanitation and hygiene 2000-2017. Special focus on inequalities." June, 2019. https://www.unicef.org/reports/progress-on-drinking-water-sanitationand-hygiene-2019

10. Apata , Temidayo Gabriel, Sunday Idowu Ogunjimi, Mobolaji Morenike Okanlawon, Oluwaseun Bamigboye, Christopher Adara and Chinwe Egbunonu. “Growing-city pollution and sanitation: causality and evidence from major cities of southwestern Nigeria.” Urbe. Revista Brasileira de Gestão Urbana. Accessed October 21, 2022. https://doi. org/10.1590/2175-3369.011.e20180189

7. Buchholz, Katharina. " 494 Million People Still Defecate Outdoors." Statista. Novermber 19, 2021. https://www.statista.com/chart/18419/ progress-against-open-defecation/?fbclid=IwAR0CjwnaFtM1-xghD0M1 i3fQFevDHaOKVfYXrPrF0LEPrGDRxDrpxoimIyU

Unsafe Sanitation Across the Globe

11. Ukazu, Ijeoma. “Lagos Community Where ‘Shit’, Filth Serves As ‘Meal’.” The Whistler. July 16. 2019. https://thewhistler.ng/lagoscommunity-where-shit-filth-serves-as-meal/

1. Hosek, Emily. “The Troubling State of Sanitation in Rio.” RioOnWatch. August 21, 2013. https://rioonwatch.org/?p=10892

12. Corburn, Jason and Irene Karanja. “Informal settlements and a relational view of health in Nairobi, Kenya: sanitation, gender and dignity.” Health Promotion International. November, 2014. 10.1093/ heapro/dau100

2. The Water and Sanitation Program (WSP). “Fiscal Year 2014 Results.” Accessed October 21, 2022. https://www.wsp.org/index.php/content/ latin-america-and-caribbean

13. Ghani, Hassan. “How to deal with Kibera’s ‘flying toilets’.” Al Jazeera. April 3, 2017. https://www.aljazeera.com/features/2017/4/3/how-todeal-with-kiberas-flying-toilets

Global Sharing Toilet

3. Tshabalala, Thandeka and Baraka Mwau. “Langrug: More than mere taps and toilets. Creating a community space through collaboration.” Community resilience and vulnerability in South Africa (29-37). https:// sasdialliance.org.za/wp-content/uploads/2020/07/SoLG.2014-CORC.pdf 4. African Population and Health Research Center. 2014. “Population and Health Dynamics in Nairobi’s Informal Settlements: Report of the Nairobi Cross-sectional Slums Survey (NCSS) 2012.” Nairobi: APHRC. Accessed October 21, 2022. https://www.kibera.org.uk/factsinfo/#:~:text=Kibera%20Facts%20%26%20Information,about%20 250%2C000%20of%20these%20people 5. ID4D. “The unexpected link between access to toilets and women’s rights.” Last modified June 17, 2021. https://ideas4development.org/ en/unexpected-link-access-toilets-womens-rights/ 6. Weru, Jane and William Cobbett. “Slum Upgrading in Kenya: What Are the Conditions for Success?.” Cities Alliance News. February 26, 2021. https://www.citiesalliance.org/newsroom/news/cities-alliancenews/slum-upgrading-kenya-what-are-conditions-success

11. Biplob, Pramanik, Dipok Chandra Sarker and Ram Chandra Sarker. “Assessment of Water Supply and Sanitation Facilities for Korail Slum in Dhaka City.” International Journal of Civil & Environmental Engineering IJCEE-IJENS 11, No. 5 (October, 2011): 115-128. https:// www.researchgate.net/publication/282062799_Assessment_of_Water_ Supply_and_Sanitation_Facilities_for_Korail_Slum_in_Dhaka_City

USER Profile 1. “Female-friendly public and community toilets: a guide for planners and decision makers.” WaterAid. Accessed October 22, 2022. https:// washmatters.wateraid.org/publications/female-friendly-public-andcommunity-toilets-a-guide-for-planners-and-decision-makers

Sharing Quota 1. Bill & Melinda Gates Foundation. “Reinvent The Toilet Fair: India, March 2014.” Accessed October 22, 2022. https://docs.gatesfoundation. org/documents/Reinvent%20the%20Toilet%20Fair%20India%20 2014%20Technical%20Guide.pdf 2. Namati. “Banka BioLoo Ltd, is a for profit sanitation product manufacturing and service provider.” Accessed October 22, 2022. https://namati.org/network/organization/banka-bioloo-ltd/ 3. Onyango, P. and C. Rieck. “Public toilet with biogas plant and water kiosk Naivasha, Kenya - Case study of sustainable sanitation projects.” SuSanA. Accessed August 15, 2022. https://www.susana.org/en/ knowledge-hub/resources-and-publications/case-studies/details/131 4. Just, Matthew R., Stephen W. Carden, Sheng Li, Kelly K. Baker, Manoj Gambhir and Isaac Chun-Hai Fung. “The impact of shared sanitation facilities on diarrheal diseases with and without an environmental reservoir: a modeling study.” Pathogens and Global Health 112, no. 4 (June 2018): 195-202. https://doi.org/10.1080/20477724.2018.1478927

EXPENSE

7. ReliefWeb. “UGANDA: "Flying toilets" still not grounded.” January 08, 2010. https://reliefweb.int/report/uganda/uganda-flying-toilets-stillnot-grounded

Agents

8. Times Of India. “Raising a stink! 145 people compete for one toilet seat in Govandi Slum.” November 19, 2018. https://timesofindia. indiatimes.com/city/thane/raising-a-stink-145-people-compete-forone-toilet-seat-in-govandi-slums/articleshow/66685546.cms

1. Bill & Melinda Gates Foundation. “Reinvent The Toilet Fair: India, March 2014.” Accessed October 22, 2022. https://docs.gatesfoundation. org/documents/Reinvent%20the%20Toilet%20Fair%20India%20 2014%20Technical%20Guide.pdf

9. Sinha, Kounteya. “ One toilet for 1,440 people at Dharavi.” Times Of India. November 10, 2006. https://timesofindia.indiatimes.com/india/ one-toilet-for-1440-people-at-dharavi/articleshow/387002.cms

2. Namati. “Banka BioLoo Ltd, is a for profit sanitation product manufacturing and service provider.” Accessed October 22, 2022. https://namati.org/network/organization/banka-bioloo-ltd/

10. “Wash challenges in slum areas of Dhaka city”. Australian Aid, ITN-BUET and Oxfam. Accessed October 21, 2022. https://www. researchgate.net/publication/319348913_WASH_Challenges_in_Slum_ Areas_of_Dhaka_City

3. Onyango, P. and C. Rieck. “Public toilet with biogas plant and water kiosk Naivasha, Kenya - Case study of sustainable sanitation projects.” SuSanA. Accessed August 15, 2022. https://www.susana. org/en/knowledge-hub/resources-and-publications/case-studies/ details/131

156

Off-grid Toilets

Installation Cost 1. Bill & Melinda Gates Foundation. “Reinvent The Toilet Fair: India, March 2014.” Accessed October 22, 2022. https://docs.gatesfoundation. org/documents/Reinvent%20the%20Toilet%20Fair%20India%20 2014%20Technical%20Guide.pdf 2. Pathak, Dr. Bindeshwar. “Sulabh Flush Compost Toilet.” Engineering For Change. Accessed October 30,2022. https://www. engineeringforchange.org/solutions/product/sulabh-flush-composttoilet/ 3. UNHCR and Boston Consulting Group, 2015. “Improving Sanitation in Refugee Camps.” 2015. https://wash.unhcr.org/download/improvingsanitation-in-refugee-camps/ 4. Larsen, Tove A. “ Grant on Advanced Toilet with On-Site Water Recovery (Eawag and EOOS, Switzerland and Austria) – Blue diversion toilet.” SuSanA. August 09, 2012. https://forum.susana.org/106-userinterface-technology-innovations/2956-grant-on-advanced-toilet-withon-site-water-recovery-eawag-and-eoos-switzerland-and-austria-bluediversion-toilet

157

5. Banka BioLoo Limited. “Banka BioLoo.” Engineering For Change. Accessed October 30,2022. https://www.engineeringforchange.org/ solutions/product/banka-bioloo/ 7. Weller, Chris. “4 toilets of the future that are backed by Bill Gates.” Insider. March 16, 2016. https://www.businessinsider.com/innovativetoilets-backed-by-bill-gates-2016-3?fbclid=IwAR2EROG27G7nKKvihjobkCzCotCrVFQhT1yhD-4noXI7b25wyDH42pGiiA 8. Koottatep, Thammarat, Stephanie Connelly, Tatchai Pussayanavin, Sopida Khamyai, Wattanapong Sangchun, William Sloan and Chongrak Polprasert. “‘Solar septic tank’: evaluation of innovative decentralized treatment of blackwater in developing countries.” Journal of Water, Sanitation and Hygiene for Development 10, no. 4 (December 2020): 828-840. https://doi.org/10.2166/washdev.2020.168 9. Onyango, P. and C. Rieck. “Public toilet with biogas plant and water kiosk Naivasha, Kenya - Case study of sustainable sanitation projects.” SuSanA. Accessed August 15, 2022. https://www.susana.org/en/ knowledge-hub/resources-and-publications/case-studies/details/131 Efficiency 10. Bill & Melinda Gates Foundation. “Reinvent The Toilet Fair: India, March 2014.” Accessed October 22, 2022. https://docs.gatesfoundation. org/documents/Reinvent%20the%20Toilet%20Fair%20India%20 2014%20Technical%20Guide.pdf

BUILT ENVIRONMENT Use 1. Yoshiharu Asano, A Study on estimating the optimum number of

Comparative Classification

fixtures in multipurpouse stadium lavatory, ( Nagano, Japan: Faculty of Architecture and Engineering, Shinshu University, 2001)

NATURAL ENVRIONMENT Climate 1. SolarPACES. “Potential for Solar Thermal Energy By Country.” Accessed October 22, 2022. https://www.solarpaces.org/csptechnologies/csp-potential-solar-thermal-energy-by-member-nation/ 2. Wikipedia.2022. “List of countries by average yearly temperature.” Wikimedia Foundation. Last modified October 14, 2022, 09:38. https:// en.wikipedia.org/wiki/List_of_countries_by_average_yearly_temperature 3. The European Space Agency. “Global wind atlas.” Accessed October 22, 2022. https://www.esa.int/ESA_Multimedia/Images/2018/01/Global_ wind_atlas 4. Fensholt, Rasmus, Stephanie Horion, Torbern Tagesson, Andrea Ehammer, Kenneth Grogan, Feng Tian, Silvia Huber, Jan Verbesselt, Stephen D. Prince, Compton J. Tucker, and Kjeld Rasmussen. “Assessment of Vegetation Trends in Drylands from Time Series of Earth Observation Data.” January, 2015. https://www.researchgate.net/ figure/World-humidity-classes-World-Atlas-of-Desertification-UnitedNations-Environment_fig1_306167024

Impact 1. IBMichelle. “E3: Greenhouse Gas Effects (UNMODIFIED).” GoConqr. July 07, 2014. https://www.goconqr.com/note/727150/e3-greenhousegas-effects-unmodified2. Circular Ecology. “Embodied Carbon - The ICE Database.” Accessed October 22, 2022. https://circularecology.com/embodied-carbonfootprint-database.html

TECHNOLOGY Implementation 1. WSP. “A Review of EcoSan Experiencein Eastern and Southern Africa.” January, 2005. https://www.wsp.org/sites/wsp/files/publications/ af_ecosan_esa.pdf 2. EarthAuger. “Projects/Installations”Accessed August 12, 2022.http:// www.earthauger.org/indiacommunity.html 3. Onyango, P. and C. Rieck. “Public toilet with biogas plant and water kiosk Naivasha, Kenya - Case study of sustainable sanitation projects.” SuSanA. Accessed August 15, 2022. https://www.susana.org/en/ knowledge-hub/resources-and-publications/case-studies/details/131 4. Madan. “Indian railway installing eco-friendly ‘zero toilet discharge’ on coaches to keep tracks clean.” Planet Custodian. June 16, 2015. https://www.planetcustodian.com/indian-railway-installing-eco-

friendly-zero-toilet-discharge-on-coaches-to-keep-tracks-clean/3250/ 5. Borjas, Daniel. “Fresh Life Toilets: Toilets for Kenya.” The Borgen Project. November 03, 2017. https://borgenproject.org/fresh-lifetoilets-toilets-for-kenya/

18. Aerosan. “AEROSAN sustainable sanitation in Nepal.” Accessed October 22, 2022. https://www.aerosantoilets.ca/copy-of-nepal

6. Ahuja, Aastha. “Swachh Bharat Abhiyan: What Are Twin Pit Toilets?.” NDTV. November 18, 2020. https://swachhindia.ndtv.com/swachhbharat-abhiyan-what-are-twin-pit-toilets-53023/

19. Moudgil, Manu. “A Revolutionary Toilet Saves Water, Money, But It Is Ignored By Target-Obsessed Swachh Bharat Mission.” India Spend. February 19, 2019. https://www.indiaspend.com/a-revolutionary-toiletsaves-water-money-but-it-is-ignored-by-target-obsessed-swachhbharat-mission/#:~:text=In%20the%20two%20districts%2C%20140,to%20declare%20the%20villages%20ODF

7. Snoad, C. “Tiger Worm Toilet: One Stop Shop Manual.” Elrha. March 28, 2019. https://www.elrha.org/researchdatabase/tiger-worm-toiletmanual-globally-relevant-learnings-from-myanmar/

20. Rotary Club Of Caloundra. “A new project to provide Bio Toilets in India.” Accessed October 22, 2022. https://www.rotaryclubcaloundra. com.au/stories/a-new-project-to-provide-bio-toilets-in-india

8. Mint. “Indian Railways has installed bio toilets across 68,000 coaches.” June 06, 2020. https://www.livemint.com/news/ india/indian-railways-has-installed-bio-toilets-across-68-000coaches-11591405535758.html

21. Banka Bio. "Banka Bioloo: We Impact India's Sanitation Value Chain every day." Accessed October 22, 2022. https://www.bankabio.com/ wp-content/uploads/2020/07/Banka-BioLoo-Brochure.pdf

9. Economic Times. “Railways installed over 1 lakh bio-toilets in trains: Government.” March 16, 2018

22. Engineering For Change. “Banka BioLoo.” Accessed October 22, 2022. https://www.engineeringforchange.org/solutions/product/bankabioloo/

10. DRDO. “DRDO Biotoilet for plains.” Accessed October 22, 2022. https://www.drdo.gov.in/drdo-biotoilet-plains

23. Climate Foundation. “India, Biochar, and Toilets.” March 31, 2014. https://www.climatefoundation.org/india-biochar-and-toilets.html

11. Moudgil, Manu. “A Revolutionary Toilet Saves Water, Money, But It Is Ignored By Target-Obsessed Swachh Bharat Mission.” India Spend. February 19, 2019. https://www.indiaspend.com/a-revolutionary-toiletsaves-water-money-but-it-is-ignored-by-target-obsessed-swachhbharat-mission/#:~:text=In%20the%20two%20districts%2C%20140,to%20declare%20the%20villages%20ODF

24. Eawag. “The Blue Diversion Toilet Business Model.” Accessed August 14, 2022. https://www.eawag.ch/en/department/ess/projects/ business-model-thinking-for-converting-new-technologies-intopoverty-alleviation/blue-diversion-toilet-business-model/

12. Ali, Mohammad. “Functionality analysis of ecosan latrines in rural areas of Bangladesh based on environment and health aspects.” 13. International Training Network Centre (ITN-BUET) and Bangladesh University of Engineering & Technology. “Report: Biofil Toilet Evaluation - Rohingya Camp, Cox’s Bazar, Bangladesh.” ReliefWeb. July 11, 2020. https://reliefweb.int/report/bangladesh/report-biofil-toilet-evaluationrohingya-camp-cox-s-bazar-bangladesh

25. Connelly, Stephanie, Tatchai Pussayanavin, Richard J. RandleBoggis, Araya Wicheansan, Suparat Jampathong, Ciara Keating, Umer Z. Ijaz, Willian T. Sloan and Thammarat Koottatep “Solar Septic Tank: Next Generation Sequencing Reveals Effluent Microbial Community Composition as a Useful Index of System Performance.” MDPI. Accessed October 22, 2022. https://www.mdpi.com/20734441/11/12/2660/htm

15. Sanergy. Accessed October 22, 2022. https://www.sanergy.com/

26. Talsma, Laura. “Conversion of human waste into biochar using pyrolysis at a community-scale facility in Kenya (Stanford University and Climate Foundation, USA and Kenya)”. SuSanA. August 26, 2013. https://forum.susana.org/169-production-of-biochar-fuel-orelectricity/5430-conversion-of-human-waste-into-biochar-usingpyrolysis-at-a-community-scale-facility-in-kenya-stanford-universityand-climate-foundation-usa-and-kenya

16. Shantz, Andrew, “Learning Brief: Alternating Twin-Pit Latrines– A solution to the emerging faecal sludge challenge?.” SNV. February, 2020. https://snv.org/assets/explore/download/2020-alt-twin-pitlatrines-cambodia.pdf

27. Romell, Rick. “Kohler Helps Caltech in Quest to Reinvent Toilet for World's Poor.” Milwaukee Journal Sentinel. January 18, 2014. https:// archive.jsonline.com/news/topstories/kohler-helps-caltech-in-quest-toreinvent-toilet-for-worlds-poor-b99184547z1-241042421.html/.

17. Balch, Oliver. “The waterless toilet that turns your poo into power.” Guardian. February 07, 2016. https://www.theguardian.com/ sustainable-business/2016/feb/07/waterless-toilet-turns-your-poointo-power-nano-membrane-technology

TIME

14. Hill, Jake. “The Tiger Toilet Turns Waste into Fertilizer.” BORGEN. March 21, 2021. https://www.borgenmagazine.com/the-tiger-toilet/.

Maintenance and obsolescene 1. Sanergy. “Sanergy: Sustainable Solutions for Growing Cities.”

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September 01, 2016. Video, 4:18. https://www.youtube.com/ watch?v=Q_xFEVmXWjE&ab_channel=Sanergy 2. EarthAuger. “Operations”Accessed August 12, 2022.http://www. earthauger.org/indiacommunity.html 3. Sandec Eawag. “Overview of the Blue Diversion sanitation system.” March 20, 2014. Video, 2:30. https://www.youtube.com/ watch?v=fjKGcVzqCjk 4. CranfieldUni. “The Cranfield nanomembrane toilet - how it works....” October 20, 2016. Video, 3:20. https://www.youtube.com/ watch?v=jGPpXF7y9Rg&ab_channel=CranfieldUni 5. RTI International. “RTI International receives additional funding from Gates Foundation to advance toilet reinvention.” November 18, 2013. https://www.rti.org/news/rti-international-receives-additional-fundinggates-foundation-advance-toilet-reinvention 6. Biofilcom Bangladesh. Accessed October 30,2022. https://www. biofilbd.com/ 7. IndiaWater Portal. “Constructing an ecosan toilet -- A film from UNICEF.” August 09, 2019. Video, 3:10. https://www.youtube.com/ watch?v=YV-1To9DkJQ&ab_channel=IndiaWaterPortal

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8. Rieck, Christian and Patrick Onyango. “Public toilet with biogas plant and water kiosk Naivasha, Kenya - Case study of sustainable sanitation projects.” SuSanA. Accessed October 30, 2022. https://www. susana.org/_resources/documents/default/2-131-en-susana-cs-kenyanaivasha-biogas-public-toilet-final-2009.pdf 9. Shrachi Ecopal. “Technology.” Accessed October 30, 2022. https:// www.shrachiecopal.com/technology

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RESEARCH TEAM

COLLABORATORS and RESEARCH TEAM

PRINCIPAL INVESTIGATOR

COLLABORATORS Professor Adnan Morshed is an architect, architectural historian and theorist, urbanist, columnist, and public intellectual. His research interests include history of visionary urbanism; history and theory of global architecture; histories of ancient water management; urbanism in developing countries; urban poverty, and social justice in spatial theories and policies. In 2017/18, he served as Chairperson of the Department of Architecture at BRAC University, Dhaka, when he also founded the Centre for Inclusive Architecture and Urbanism (Ci+AU), which he currently directs. He also teaches at the School of Architecture and Planning, Catholic University of America, Washington.

Mr. Faysal Abbas is a development practitioner working at WaterAid since 2016. He has over 12 years of experience in the field of strategic influencing, advocacy, and communications in development sector. Under his portfolio at WaterAid he also leads the media and public engagement work at Bangladesh. He has been instrumental in Bangladesh’s advocacy landscape over the past six years with direct engagement in rightsbased inclusive WASH agendas. Faysal is a graduate from journalism and media studies background, with masters in peace, human rights, and development studies. He has a keen interest in South Asia identity politics, peace, and conflicts.

Dr Md Khairul Islam is one of the leading public health and development professionals of Bangladesh. He has worked in various capacities in different development organizations in Bangladesh and Africa. Dr. Islam has been associated with the drafting of the national health policy and national population policy of Bangladesh; and sits in several policy making committees related to water, sanitation and hygiene in Bangladesh and in the region. Prior to assuming the responsibility of the Regional Director of South Asia region recently, he has worked in the field of water, sanitation and hygiene as the Country Director of WaterAid Bangladesh for eleven years. He has authored and co-authored several papers on public health and water, sanitation and hygiene in peer-reviewed journals and published monographs.

Ms. Vanita Suneja is an independent researcher with part of her time committed to gender equality and development. For over 29 years she worked with various institutions in the areas of Water, Sanitation, and Hygiene (WASH), Environment and Social Justice. She has experience of working in South Asia and was leading the policy work with WaterAid as South Asia, Regional Advocacy Manager. Prior to that she was leading Economic Justice portfolio of Oxfam India and has worked with Society for Promotion of Wastelands Development for many years on rural livelihoods and natural resource conservation.

Dr Paco Mejias Villatoro is an architect, urban planner and academic, codirector of Open Studio, a collaborative think-and-do tank, operating at the intersection between architecture and urbanism (www. thisstudioisopen). He has an expertise in community design, empathic urbanism and social ecology, and he has been conducting research about ultra-dense urbanism and informal settlements, particularly focused in Dhaka since 2014. He has been teaching architecture and urban planning since 1997 in Spain, Canada, the USA, China and the UK, where he teaches architecture at the University of Liverpool.

CO-INVESTIGATORS Dr Junjie Xi is a lecturer in architectural design and humanities at the University of Liverpool. She was previously a Postdoctoral researcher for the China Railway Group Limited and School of Architecture, Tsinghua University. She continues her research in railway development and has completed a new book with Dr Paco Mejias Villatoro - China’s Railway Transformation: History, Culture Changes and Urban Development, which is published by Routledge in December 2022. Through research in infrastructure, she developed a focus in the informal settlements in Bangladesh, aiming to provide better sanitation system for the future. Dr Tanzil Shafique is an Assistant Professor of Urban Design at The University of Sheffield School of Architecture and an Associate of the Urban Institute. His research weaves across urban informality, decoloniality and pluriversality, and brings a socio-political reading of

the built environment. He has a PhD from the University of Melbourne, where his thesis looked at the everyday design practices by citizens of the largest informal settlement in Bangladesh. Previously he worked as a Project Designer at the University of Arkansas Community Design Center. He has an M.Arch in Ecological Urbanism from Rensselaer Polytechnic Institute in New York and a B.Arch from BRAC University, Dhaka.

RESEARCH ASSISTANTS (By allocated time)

Mr Md. Fahim Hasan Rezve has been working with the University of Liverpool as a research assistant. Previously he worked as a design associate at the Centre for Inclusive Architecture and Urbanism (Ci+AU) at BRACU. He also worked as an architect at Vernacular Consultants ltd. Fahim was awarded KSRM Award for future architects in 2020 for his Barch thesis project titled ‘Revitalizing Jute Culture, a Museum for Golden Fiber’. He participated in many architectural design competitions and was awarded the DOT Student Design Award in 2019 and 2021. He received his B.Arch from American International University-Bangladesh (AIUB) in 2019. Ms Wasila Fatima Nilia completed her B.Arch. from American International University-Bangladesh, (AIUB) in 2019 and has been working with the University of Liverpool as a research assistant. She was awarded in Provabok- Model Making and Instant Design Competition 2018. Her academic work, “Museum for Ancestors,” was published in Showcase Magazine, and the design idea, “Makeshift Isolation Unit and Treatment Facility for Covid-19 Patients”, was published in Context BD. Wasila is an associate member of The Institute of Architects , Bangladesh.