Water&Sanitation Africa March/April 2020

Promoting professional excellence in the water sector The official magazine of the Water Institute of Southern Africa

Water& Sanitation Complete water resource and wastewater management

Africa

AquaPlan

The case for DAF

MASTER PLAN

Why it can succeed

SLUDGE MANAGEMENT A model for agriculture

STORMWATER

A valuable resource

March/April 2020 • ISSN 1990-8857 • R55.00 (incl. VAT) • Vol. 15 No. 02

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VOL. 15 NO. 02

MARCH/APRIL 2020 Promoting professional excellence in the water sector The official magazine of the Water Institute of Southern Africa

Water& Sanitation Complete water resource and wastewater management

Africa

AquaPlan

The case for DAF

MASTER PLAN

Why it can succeed

SLUDGE MANAGEMENT A model for agriculture

STORMWATER

A valuable resource

CONTENTS

ON THE COVER Dissolved air flotation is one of the most robust, versatile and widely used unit operations in the treatment of water worldwide. Johan Bieseman, managing director, AquaPlan, speaks about the benefits of this treatment technology. P4

March/April 2020 • ISSN 1990-8857 • R55.00 (incl. VAT) • Vol. 15 No. 02

Regulars

Editor’s comment Africa round-up Index to advertisers

Cover Story

The case for DAF

3 12 56

4

WISA

CEO’s comment 7 Chair’s comment 8 YWP 10 Events

56

Water Security

Water and climate change Why the master plan can succeed The severe consequences of load-shedding

Treatment

Desalination plant brings relief Is chlorine causing more harm than good?

Sludge Management

A model for sludge in agriculture Beneficiating sludge to the benefit of utilities Making co-digestion feasible

Stormwater

Harvesting a valuable resource

Water Loss

Getting smart about losses

Biological Control

Bugs beat back water hyacinth

Sanitation

Making products from human waste Award-winning dry sanitation

Industrial Water

Innovative replacement solution

Instrumentation & Control

The world’s toughest liquid analysis systems Surge analysis in a nutshell An IoT project with a surprising outcome

Water Storage

Make water security the top priority

8

CHAIR’S COMMENT

14 16 19 20 21

14

WATER AND CLIMATE CHANGE

23

A MODEL FOR SLUDGE IN AGRICULTURE

23 25 26 28 30 32 34 37 39

32

BUGS BEAT BACK WATER HYACINTH

43

THE WORLD’S TOUGHEST LIQUID ANALYSIS SYSTEMS

SANITATION 43 44 46 49

Groundwater

Groundwater flooding: two countries, similar challenges

Technology

Accelerating SA’s water fightback

50 52

Did you know that just one Enviro Loo can save up to 420 000 litres of water annually? P37 infrastructure news

infrastructure4

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Editor Danielle Petterson danielle.petterson@3smedia.co.za Managing editor Alastair Currie Head of design Beren Bauermeister Designer Janine Schacherl Chief sub-editor Tristan Snijders Contributors Neil Armitage, Jay Bhagwan, Lester Goldman, Sudhir Pillay, Anthony Turton, Achim Wurster Operations & production manager Antois-Leigh Botma Production coordinator Jacqueline Modise Distribution manager Nomsa Masina Distribution coordinator Asha Pursotham Group sales manager Chilomia Van Wijk Financial manager Andrew Lobban Bookkeeper Tonya Hebenton Printers Novus Print KZN Advertising sales Hanlie Fintelman t +27 (0)11 467 6223 | c +27 (0)82 338 2266 Hanlie.Fintelman@3smedia.co.za

Publisher Jacques Breytenbach 3S Media 46 Milkyway Avenue, Frankenwald, 2090 PO Box 92026, Norwood 2117 Tel: +27 (0)11 233 2600 Fax: +27 (0)11 234 7274/5 www.3smedia.co.za

ISSN: 1990 - 8857 Annual subscription: R330 (SA rate) subs@3smedia.co.za Copyright 2020. All rights reserved. All articles herein are

copyright protected and may not be reproduced either in whole or in part without the prior written permission of the publishers. The views of contributors do not necessarily reflect those of the Water Institute of Southern Africa or the publishers.

WISA’s Vision

Inspiring passion for water

WISA Contacts: HEAD OFFICE Tel: 086 111 9472(WISA) Fax: +27 (0)11 315 1258 Physical address: 1st Floor, Building 5, Constantia Park, 546 16th Road, Randjiespark Ext 7, Midrand Website: www.wisa.org.za BRANCHES Central Branch (Free State, Northern Cape, North West) Chairperson: Dr Leana Esterhuizen Company: Central University of Technology Tel: +27 (0)51 507 3850 Email: lesterhu@cut.ac.za Eastern Cape: Branch Contact: Dan Abrahams Company: Aurecon Tel: +27 (0)41 503 3929 Cell: +27 (0) 81 289 1624 Email: Dan.Abraham@aurecongroup.com Gauteng Branch Lead: Zoe Gebhardt Cell: +27 (0)82 3580876 Email: zoe.gebhardt@gmail.com KwaZulu-Natal Chairperson: Lindelani Sibiya Company: Umgeni Water Cell: +27 (0)82 928 1081 Email: lindelani.sibiya@umgeni.co.za Limpopo Chairperson: Mpho Chokolo Company: Lepelle Northern Water Cell: +27 (0)72 310 7576 Email: mphoc@lepelle.co.za Mpumalanga Chairperson: Lihle Mbatha (Acting) Company: Inkomati-Usuthu Catchment Management Agency Tel: +27 (0)13 753 9000 Email: mbathat@iucma.co.za

EDITOR’S COMMENT

RECAPACITATING THE STATE

T

he GDP figures for the fourth quarter of 2019 show a 1.4% contraction in the economy, plunging South Africa into its third recession since 1994 in the second half of 2019. Construction was the third worst affected sector, with a decline of 5.9%, followed by electricity, gas and water, which saw a 4% decline.

This poor growth is of great concern considering that South Africa will also be negatively affected by global trade wars and the impacts of the Covid-19 outbreak.

Budget speech Minister Tito Mboweni’s 2020 Budget Speech received mixed reactions. While many were relieved to see no major tax increases, labour unions were quick to denounce the minister’s plans to cut the public sector wage bill by R160.2 billion over three years. This substantial cut comes in light of South Africa’s growing financial deficit. In fact, servicing debt is now our third biggest budget expense.

We are now highly reliant on government to successfully negotiate with labour unions to ensure the necessary cut in the wage bill.

Dr Azar Jammine, director and chief economist at Econometrix, has warned that if South Africa does not manage to control its growing public debt, the country could soon end up in a very similar situation to Greece’s sovereign debt crisis, which saw it require bailout loans in 2010, 2012 and 2015 from the International Monetary Fund, Eurogroup and European Central Bank.

Leaving the poor behind As the economy continues to contract, it is the poorest communities who suffer most. Unfortunately, the country has seen a rise in poverty levels in recent years, and progress that was made in eradicating poverty is being undone.

In March, we celebrate World Water Day, which forces us to consider SDG 6: water

and sanitation for all by 2030. Over 3 million South Africans still do not have access to a basic water supply service and 14.1 million people do not have access to safe sanitation.

Unfortunately, it is these poor, sometimes forgotten, communities who are likely to continue to suffer without the basic necessity of water and the dignity of sanitation, as the country grapples with a potentially looming financial crisis.

Focus on skills President Cyril Ramaphosa has highlighted the haemorrhaging of skills in the public sector, which undermines planning, asset management and the creation of a credible pipeline of infrastructure projects.

In response, industry associations such as WISA and CESA have begun to call on the private sector to offer skills and support to the public sector. According to a recent CESA survey, one in five people in all consulting firms is not gainfully employed. The capacity therefore exists for a short- to medium-term measure to utilise private sector skills to capacitate the state.

WISA recently put out a request for skilled unemployed or under-employed members who would like to offer their services to the Department of Human Settlements, Water and Sanitation to add their names to a skills database.

It is encouraging to see the private sector working to collaborate with government.

If initiatives like these can succeed, we may well see a turnaround in service delivery and, hopefully, the economy.

Danielle

Promoting professional excellence in the water sector The official magazine of the Water Institute of Southern Africa

Water& Sanitation Complete water resource and wastewater management

Africa

AquaPlan

Western Cape Chairperson: Natasia van Binsbergen Company: AL Abbott & Associates Tel: +27 (0)21 448 6340 Cell: +27 (0)83 326 3887 Email: natasia@alabbott.co.za

The case for DAF

COVER OPPORTUNITY In each issue, Water&Sanitation Africa offers companies the opportunity to get to the front of the line by placing a company, product or service on the front cover of the magazine. Buying this position will afford the advertiser the cover story and maximum exposure. For more information, contact Hanlie Fintelman on +27 (0)11 467 6223, or email

Namibia Please contact the WISA Head Office on admin@wisa.org.za for more information

Hanlie.Fintelman@3smedia.co.za MASTER PLAN

Why it can succeed

SLUDGE MANAGEMENT A model for agriculture

STORMWATER

A valuable resource

March/April 2020 • ISSN 1990-8857 • R55.00 (incl. VAT) • Vol. 15 No. 02

M A R /A P R 2020

3

COVER STORY

Dissolved air flotation is one of the most robust, versatile and widely used unit operations in the treatment of water worldwide.

Johan Bieseman, managing director, AquaPlan, speaks to Water&Sanitation Africa about the benefits of this treatment technology.

Why is dissolved air flotation (DAF) an increasingly popular option for clients/ end users?

JB In the past, DAF systems were often a wish list item. Today, DAF systems have become an intrinsic part of the process of treating water due to their very efficient and cost-effective removal of, among others, suspended solids, chemical oxygen demand and phosphorus in wastewater.

This trend has picked up over the past few years, as more pressure is mounting on industries and governments alike to consider the reuse of water in various applications.

In which cases can DAF be considered the best available technology?

DAF systems have been utilised in the water treatment processes for industrial effluents from steel mills, oil refineries, chemical plants, paper mills, and effluents from food and beverage processes.

The implementation of a skid-mounted, modular, cost-effective DAF system as part of the process to produce clear,

The case for DAF

treated water from industrial effluent from almost any source of water – including wastewaters with high organic content, suspended solids and colour – cannot be over-emphasised.

A well-placed, well-designed DAF system offers unprecedented advantages for both up- and downstream processes as part of both the removal of pollutants in the water, as well as the protection of membrane processes downstream of the DAF. Our three most recent installations serve as pre-treatment in the preparation of drinking water from the polluted effluent in food and beverage processes.

How does DAF measure up in terms of lead time and cost?

AquaPlan has developed a robust, simple, easy-to-operate and versatile range of DAF systems that encompass the dissolving of air, recirculation of white water, as well as the distribution and separation of particles in one simple, skid-mounted system. The material of construction ranges from epoxy-coated carbon steel to 316 stainless steel as the material of choice in food and beverage as well as papermaking applications. All the materials utilised in the manufacturing of a complete DAF system are readily available in the local South African market.

Our skid-mounted systems are well suited to be installed into current processes as a pre-treatment to both ultrafiltration and reverse osmosis systems, as well as a post-treatment step for biological processes such as MBR, MBBR and SBR systems. Coupled to welldesigned biological systems, the removal and carry-over of suspended and organic matter to post-treatment processes pose a direct threat to the longevity and sustainability of membrane processes.

The DAF system is very cost-effective in removing oils, fats, greases, organic compounds, and very fine colloidal suspended solids in one easy process, which effectively removes these unwanted particles from the chain.

The process is extremely energy efficient and the float collection mechanism has no moving parts; the waste floats can be lifted off with a simple and automatic hydraulic jump.

The equipment is placed on a simple and cost-effective concrete slab, or plinth, by merely lifting the complete system into position. Quick, simple and efficient, the DAF system can be installed and commissioned within two to three days.

The low maintenance costs associated with the system, as well as the costeffective spare parts that are readily available, are welcomed in the industry.

What makes AquaPlan particularly suited to supply DAFs? AquaPlan has successfully designed, manufactured, installed and commissioned many DAF applications and a wide variety of effluent water and applications over the past 25 years. Our specific in-house experiences in different applications have necessitated optimisation changes to each process, best suited for the application.

The current AquaPlan DAF system comprises a fully integrated air saturation and recirculation pump system, flotation basin, lamella-pack integrated settler tubes, scum flotation system, and conical sludge removal underflow, all on to one integrated skid-mounted frame, ready for installation.

Our range of systems are simple and quick to install, and cover a very small footprint for large flow rates when compared to conventional clarification systems.

Is DAF particularly suited to the South African water sector or is it simply a generalapplication technology?

The biggest driver of recycling water, or reusing any treated effluent, is believed to be the sustainability of water securities, as the availability of both groundwater and surface water resources is rapidly diminishing. The reuse of wastewater will be an absolute necessity when the normal sources run dry or are contaminated. This holds true as a worldwide application and not specifically only in the South African context.

South Africa is an arid country with a low average rainfall, where reservoirs and water storage capacities are often extremely low.

With the projected population growth over the next 10 years, coupled to the effects of global warming and shifting weather patterns, the use and reuse of water in South Africa as a water source to augment natural sources is a great opportunity to drive sustainability. It is projected that large wastewater works in South Africa that are well established and near city metropoles will adjust their way of treatment through the inclusion of DAF systems. This will provide sources of drinking water to communities who currently simply do not have a sustainable source of drinking water.

Is there work to be done in terms of changing people’s attitudes towards effluent and wastewater treated for potable use – even with using DAF as pre-treatment?

There is indeed a lot of work to be done. While more pristine natural resources diminish, and the environmental degradation of sustainable habitats is more and more evident as a direct result of industrial activity,

the shift to utilise industrial effluent water or wastewater for drinking water will grow exponentially.

The technology already exists to produce drinking water from a wide range of non-potable sources such as acid mine drainage, seawater and raw sewage at city outfall points. As responsible citizens, we each have a vested interest in not only minimising waste, but utilising our waste streams in environmentally responsible ways, reducing our carbon footprint and conserving energy. Drinking our own treated waste is slowly gained traction and is indeed our future.

Industrial effluent and human wastewater comprise all the unwanted and toxic elements a design engineer in water treatment can be confronted with.

These include organic matter, viruses, bacteria, as well as suspended mater, oils and fats that need to be removed.

To this effect, a well-positioned DAF is critical in removing most of these constituents. One of the biggest challenges to this process is the protection of the equipment against fouling, blocking and to guard against high energy and maintenance costs within the system.

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M A R /A P R 2020

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WISA • CEO’S COMMENT

ADAPTING TO A NEW NORMAL

A

s we get ready to observe World Water Day in March, we are reminded that our WISA 2020 Conference is fast approaching.

We all know that we are facing increasing water demands to meet the needs of a rapidly growing and urbanising society, economic growth and changing lifestyles. With only 10 more years to achieve our SDGs, we need #AllHandsOnDeck to address the water challenges we are faced with.

South Africa is facing a water crisis as a result of insufficient water infrastructure maintenance and investment, recurrent droughts and

floods driven by climatic variation, inequities in access to services, deteriorating water quality, and a lack of skilled water practitioners.

The country’s National Water and Sanitation Master Plan warns that the impacts of the growing water crisis will be exacerbated if not addressed and could lead to a 17% water deficit by 2030. If this becomes a reality, South Africa’s chances of achieving SDG 6: clean water and sanitation for all by 2030 will fall by the wayside.

The master plan, like the WISA 2020 Conference, seeks to rally all water sector stakeholders in South Africa to work together in order to ensure that the country gets ahead of the curve in relation to both current and future challenges.

WISA 2020

The WISA 2020 Biennial Conference and Exhibition, being held in Sandton from 31 May to 4 June, provides a platform for these issues to be discussed, solutions shared, and decisions taken.

It is imperative that the country embraces a few fundamental shifts around water. Our water resources are limited, and we have to start doing more with less. In a country such as South Africa, the work done by the water sector has a major influence on the sustainability and success of our communities and our economy. For WISA, our biennial conference is a reflection of the vital role that we have to play as we adapt to the new, water-constrained, normal.

WISA 2020 therefore aims to speed up delivery and bring purposeful feedback to the leadership of South Africa. The six thematic streams promise to provide enough platforms for you to interact and suggest solutions to the challenges we face. You will have the opportunity to listen to local and global experts and challenge them to define the solutions we need.

Sector leaders will mingle with sector experts, and the layman, to address such challenges.

Continuous professional development should also be about applying learning, and the conference is the perfect opportunity to see this in action.

For more information about the conference, please visit our website: www.wisa2020.org.za.

We hope you will join us at WISA 2020 and help us get #AllHandsOnDeck for a sustainable water future.

Dr Lester Goldman, CEO, WISA

M A R /A P R 2020

7

WISA • CHAIR’S COMMENT

Water rights or responsibilities?

We will be celebrating National Water Week and World Water Day in March. What does this mean to you? The right to access sufficient clean water to sustain life is enshrined in our Constitution; however, this alone neither gives effect to nor ensures that the right to water is realised.

By Achim Wurster, chair, WISA

Achim Wurster, chair, WISA

A

s South Africans, we have what is considered by many as some of the most progressive water-related legislation. On paper, the legislation and structures put in place to give effect to the rights enshrined in the Constitution seem ideally suited to ensure that all South Africans experience the benefits. Scanning the news reports, however, paints a different picture, with regular reports of protest action due to lack of water services delivery or reports of water outages due to infrastructure failure.

So, what are the underlying causes that prevent us from ensuring the rights are not just a nice-sounding idea but are a lived experience? The following is a list of just some of the reasons that come to mind: • Commercial operations including industry, farming and mining often use water outside of their licence conditions, abstracting and using too much water or discharging poorly treated wastewater.

• Water boards and state-owned entities are responsible for our bulk water supply infrastructure.

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MAR /APR 2020

There are often news reports of corruption and mismanagement of large sums of money in the associated infrastructure projects. At times, the level of infrastructure maintenance is inadequate. National Treasury funding is under pressure and the end users are reluctant to pay more for water services.

• Municipal budgets for water-related infrastructure and services are always under pressure from competing interests and glamour projects designed to get politicians re-elected.

This applies especially to sewage treatment infrastructure, resulting in many municipalities discharging partially treated or untreated sewage.

Corruption and mismanagement of the already inadequate funds that are directed to water infrastructure make the situation worse. Many municipalities also do not pay their bills, placing excessive financial strain on the water boards. Municipal infrastructure is intentionally vandalised by criminal elements who sell parts as scrap or to ensure that a connected individual benefits from a contract for the provision of water tanker services.

• Individuals that are either unaware, selfish, or simply don’t care about their fellow citizens, misuse water services by illegally connecting to water services, not paying for services received or by illegally discharging toxic waste into sewers or the environment.

• The regulator and law enforcement bodies are not effective at ensuring that our otherwise good laws are enforced. The regulator may be conflicted, as it is also acting as an implementing agent and regulating yourself is not always easy. The law enforcement agencies are typically overwhelmed trying to enforce other more serious crimes, or they are at times also susceptible to corruption.

Often, the only thing that commercial entities, water boards, municipalities and individuals alike have that prevents them from operating outside of the law are the moral standards of the individuals in the various organisations.

A different approach

For you and every other South African citizen, the result of the above is that

WISA • CHAIR’S COMMENT

we are paying more for a water supply that is less reliable and for water that is of a lower quality. This is also why South Africa has not managed to give effect to the water rights enshrined in our Constitution to each and every citizen.

So, what now?

I propose that we approach the matter from the other side; instead of focusing on our rights, let us focus on our responsibilities. If each individual in our society would ask, “What is my responsibility?” and act accordingly, then we would live in a utopia. While this is not realistic, we could – as a

society and individuals – decide to think bigger and longer term, as well as change our values to at least not cause harm or shift burdens to others.

Therefore, it is up to you to: •M ake choices that show a regard for the law and the rest of society, whether in your capacity as an employee in industry, farming, mining, water board, municipality or regulator, as well as in your private capacity at home and when interacting with the rest of society.

•S peak up and be an agent for changing values in the rest of society: to educate

and inform the rest of society on the benefits to all if we work together because our individual interest and the common interest are intertwined when it comes to water.

• Hold politicians, the regulator and law enforcement agencies accountable for the policies they make and decisions they take.

Focusing on our responsibilities is the only feasible way for South Africa to achieve the right to clean water for all as our Constitution intends. To borrow from the WISA 2020 Conference theme, this once again requires #AllHandsOnDeck.

WISA • Y WP

The #AllHandsOnDeck WISA 2020 Conference will take place from 31 May to 4 June 2020 at the Sandton Convention Centre in Johannesburg.

A

s part of the #AllHandsOnDeck movement, the Young Water Professionals (YWP) empowerment platform of WISA will be coordinating a number of events and sessions during the conference. We invite you to familiarise yourself with the sessions and please volunteer your name to participate in any of these sessions.

YWP presents exciting programme at WISA 2020

For the rapporteur programme, we will bring YWPs together to debate on key issues from the conference. An almost week-long programme of working together with other YWPs promotes relationship building and trust – the foundation of a growing network in the South African water and sanitation sector.

Rapporteur programme

A rapporteur programme, coordinated by YWP, will run for the duration of the WISA conference.

Volunteers to this programme will be expected to participate in planning meetings leading up to the conference, attend sessions representative of the conference sub-themes to capture key messages, work with teams to summarise the key messages from the sessions and report back at the YWP Forum.

The objective of the rapporteur programme is to ensure that the emerging messages from the various conference sessions and sub-themes are represented and debated upon during the YWP Forum.

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MAR /APR 2020

YWP Forum

The YWP Forum will take place on Day 3 of the conference and will run

as an interactive session. It is open for everyone to attend. The objective of the forum is to debate on the key messages emerging from the conference that will be presented by the rapporteurs. The debate will include a brainstorming session on what we think may be solutions/improvements to challenges and current practices and how YWPs could contribute to these solutions or improvements.

The YWP Forum will be the flagship event for YWP at the WISA Conference.

The outcomes from the forum session will be consolidated and integrated into the conference feedback.

The YWP Forum 2020 is therefore a unique opportunity for all YWPs attending the conference to have their voices heard, contribute to the future thinking of the South African water sector, and to be part of a community of young people set to make a difference.

YWP-ZA would like to invite all YWPs interested in having #AllHandsOnDeck and their voices heard to volunteer

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WISA • Y WP

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Other sessions

YWP will be involved in several other sessions: • Opening and closing plenaries on Day 3 (June 3) of the conference.

• YWP meet and network social – more information on the date, venue and time will be posted from the @YWPZA Facebook account closer to the conference. Please check our Facebook account for the latest information.

• Wetskills South Africa Programme & Awards – participants will work together in mixed teams on water challenges provided by organisations of the local and international water sector. This edition of Wetskills will take the participants to the Gauteng region, with Johannesburg and Pretoria, and its magnificent and interesting surroundings. They will get a two-week programme with workshops and teamwork, visiting interesting water-related locations, and having the finals and awarding ceremony at the bi-annual WISA 2020 Conference. On Day 1 of the WISA 2020 Conference (1 June), the Wetskills participants will present their concepts, followed by an awards ceremony (award ceremony date and time still to be confirmed). To get the latest updates on this programme, please access https:// wetskills.com/event/ wetskills-south-africa-2020, and follow @Wetskills on Facebook and Twitter.

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Water and sanitation in Africa

EAST AFRICA GERD meetings show promise Representatives from Sudan, Egypt and Ethiopia met in Washington, DC early this year for a round of talks on the Grand Ethiopian Renaissance Dam (GERD).

The US-sponsored talks between the three nations seek to resolve a dispute over the GERD being constructed on the Blue Nile, a tributary of the Nile River.

The US, with technical support from the World Bank, has agreed to facilitate preparations of the final deal to be studied by the three countries.

Egypt has opposed the project over fears that it will stem the flow of the Nile, on which it depends for around 90% of its water supply.

Construction of the dam is well under way and expected to be completed

KENYA A sanitation crisis A recently released census report has revealed that only 9.7% of Kenya’s national population use sewered sanitation.

Data from the Kenya National Bureau of Statistics reveals that most Kenyan households are not connected to the main sewer grid and must use alternative sanitation options. More than half of the country’s 12 million households use covered pit latrines – more than 61% in rural areas and 34% in urban areas.

A significant number of households also use uncovered pit latrines or defecate in the open; 12.5% of rural households and 4.4% in urban areas use uncovered pit latrines, while 11.5% of those in rural areas and 0.8%

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MAR /APR 2020

by 2023. The hydroelectric dam will produce 6 475 MW for Ethiopia’s domestic and industrial use, as well as for export to neighbouring countries.

The three countries have reportedly reaffirmed the importance of transboundary cooperation in the development of the Blue Nile to improve the lives of the people of Egypt, Ethiopia and Sudan.

in urban areas practise open defecation.

Urban areas such as Nairobi, Mombasa and Kisumu boast higher connectivity to the main sewer line.

Currently, Nairobi is the best connected, with more than 54% of households using sewered sanitation. In Mombasa and Kisumu, the proportions of the population connected to sewers are 16.6% and 4.8%, respectively.

Unfortunately, the improvement of Kenya’s sanitation infrastructure has been slow over the last 20 years, showing little change despite other infrastructure development. Kenya has long struggled with this problem and was among the countries that did not achieve the Millennium Development Goal for increasing access to water and sanitation.

AFRICA ROUND-UP Word from around Africa – including the latest industry, project and development news.

NIGERIA Water security for farmers USAID’s new Water for Agriculture project will boost the livelihoods of farmers in the conflict-affected states of Borno, Adamawa and Yobe by improving the water supply in crisisaffected zones in north-east Nigeria.

The three-year project will reach at least 4 000 smallholder farmers and 50 000 livestock herders by constructing new earth dams and systems for crop production and livestock watering, strengthening water governance and management, improving production, and helping mitigate conflict between farmers and herders.

Water for Agriculture will also improve the capacity of local governments and communities to govern and manage water infrastructure and resources in the region.

“Water for Agriculture will play a critical role in USAID’s strategy to develop new sustainable water sources in rural communities where displaced populations are returning,” says Stephen Haykin, mission director, USAID. “It will contribute to our promotion of agriculture-led economic growth to improve resilience and nutrition, and stronger governance of the water and sanitation sector.”

WEST AFRICA Expanding WASH services The West Africa Municipal Water, Sanitation, and Hygiene (MuniWASH) activity is providing support to city governments in West Africa to improve and expand water and sanitation services to meet critical needs.

Urbanisation in the region is challenging municipalities’ ability to deliver consistent and quality water and sanitation services as well as make improvements towards the water and sanitation Sustainable Development Goals (SDGs). In both Benin and Ivory Coast, for example, millions of people lack access to basic or safely managed drinking water and sanitation services.

MuniWASH’s focus is on helping government to improve financial viability and sustainability, technical and operational performance, and governance and management oversight to bridge the gap between country national priorities and the SDGs. Currently, MuniWASH is supporting city governments, national directorates and agencies, utilities, and service providers in Benin and Ivory Coast to sustain and expand city-wide WASH services to fill critical needs that reach poor and underserved community members in priority municipalities.

ZIMBABWE Safe water sources needed A recently released Unicef report states that almost 60% of the Zimbabwe’s water sources do not provide access to safe water, leaving many families to depend on unsafe or contaminated sources, increasing the risk of diarrhoeal disease outbreaks.

The Zimbabwe Humanitarian Situation Report indicates that 1.9 million people are in need of safe drinking water, sanitation and good hygiene. However, it acknowledges that this figure may need to be revised given the growing economic challenges facing Zimbabwe and the late onset of rains.

During 2019, Unicef provided WASH responses to Zimbabwe’s cholera,

typhoid, Cyclone Idai and drought emergencies. Around 1.3 million people were reached with a safe water supply, and 158 638 people were reached with basic sanitation in emergency settings.

A recent sector review of cholera, typhoid and cyclone responses highlighted the importance of expanding rapid response teams that delivered a comprehensive WASH response to cholera and contributed to faster control of the outbreak.

Unicef also supported the development of a diarrhoea, typhoid and cholera outbreak emergency preparedness and response plan for the City of Harare as well as developing its own internal contingency plan to deal with the growing challenges facing the WASH sector in Zimbabwe.

M A R/ A P R 2020

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WATER SECURIT Y

WATER AND CLIMATE CHANGE

T

o support the achievement of Sustainable Development Goal 6 – water and sanitation for all by 2030 – World Water Day raises awareness of the 2.2 billion people living without access to safe water. Climate change must be taken into consideration as variable climates increasingly affect global water sources.

Water and climate

As climate change increases variability in the water cycle, it induces extreme weather events, reduces the predictability of water availability, affects water quality, and threatens sustainable development, biodiversity and the right to water and sanitation worldwide.

According to the UN-Water Policy Brief on Climate Change and Water, growing demand for water increases the need for energy-intensive water pumping, transportation and treatment, and has contributed to the degradation of critical water-dependent carbon sinks such as peatlands. And, some climate change mitigation measures, such as the expanded use of biofuels, can further exacerbate water scarcity.

The UN has therefore called for an integrated approach to climate change and water management in climate policy and planning, both at a national and regional scale. A business-as-usual approach is no longer an option. Instead, water management must be scrutinised through a climate resilience lens.

14

MAR /APR 2020

The global climate crisis is inextricably linked to water. This year, World Water Day highlights how climate change is already impacting on global water supplies.

The policy brief calls for more investment in improved hydrological data, institutions and governance, education and capacity development, risk assessment, and knowledge sharing. Policies need to ensure the representation, participation, behavioural change and accountability of all stakeholders.

The argument is that significant co-benefits exist to managing both climate and water in a more coordinated, sustainable manner. And solutions for addressing these integrated challenges are available. However, meeting the climate challenge means: 1. Acting now 2. Considering water as part of the solution 3. Improving water management practices 4. Ensuring transboundary cooperation in adaptation 5. Rethinking financing.

intense floods and droughts, and may also increase the agricultural demand for water due to higher temperatures and a reduced ability to rely on rain-fed agriculture.

The plan calls for a new normal to achieve water security in South Africa. This requires a significant paradigm shift that: • r ecognises the limitations of water availability •a ddresses the real value of water •e nsures equitable access to limited water resources •d elivers reliable water and sanitation services to all • f ocuses on demand management and alternative sources of water • c onsiders the impacts of climate change •a ddresses declining raw water quality.

The NW&SMP states, “The implementation of this plan will enable South Africa to become more resilient to climate change

SA acknowledges climate threat

The recently released National Water and Sanitation Master Plan (NW&SMP) acknowledges that climate change will result in there being less water available at a time when the country is dealing with increasing water demands.

Climate change is projected to increase the variability of rainfall throughout South Africa and to reduce average rainfall, particularly in the western part of the country. Climate change will result in more

DID YOU KNOW? Wetlands are the most effective carbon sinks on earth, but are declining three times faster than natural forests.

WATER SECURIT Y

FAST FACT and the increasing intensity of droughts and floods, while meeting the water needs of a growing population and economy.”

The master plan goes on to acknowledge that strong regulation is critical to achieve water security in South Africa, which includes being resilient to climate change impacts. It also calls for ongoing research, modelling and planning around climate change and its impacts on water security and water infrastructure, as well as the need to initiate a hydrological monitoring centre to re-establish a robust data, monitoring and information capability for more effective water resources planning and climate change forecasting.

Acting now

This year, the South African Department of Environment, Forestry and Fisheries has announced that it will assist municipalities to implement their climate change response strategies. The South African Weather Service will also ramp up efforts to educate local communities so they can better understand climate change and respond appropriately.

Through the department’s environmental programmes, R1.9 billion is to be spent in 2020 to restore wetlands, estuaries and coastal dunes to better protect built infrastructure and human settlements from storms, floods and rising sea levels.

South Africa will also continue to lobby developed countries to provide for an adequate, reliable and predictable source of international funding for both mitigation and adaptation.

If demand continues to grow at current levels, the deficit between water supply and demand in South Africa could be between 2.7 and 3.8 billion m3/annum by 2030 – a gap of about 17% of available surface water and groundwater.

50%

If we limit global warming to 1.5˚C, we could cut climate-induced water stress by 50% South Africans use

Climate-resilient water supply and sanitation could save more than

South Africa is the 39th driest country in the world

64 ℓ

/day

more than the global average

360 000 infants annually

By

2050, up to

5.7 billion people could be living in areas where water is scarce for at least one month a year

2040

By , global water demand is expected to double

2.2 billion

people live without access to safe water

South Africa is facing a projected

17%

water deficit by

2030

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WATER SECURIT Y

Consistent load-sheddingrelated or other major electricity disruptions can have severe consequences for the continuous treatment and supply of water services, writes Jay Bhagwan*.

S

ystems across the municipal and water board sector remain vulnerable, as per a recently completed Water Research Commission (WRC) study. The study found that, until recently, the high assurance of electricity supply did not warrant municipalities to have backup plans on its key water services infrastructure.

It is a huge concern that many large metros and municipalities have no preparedness to deal with outages, especially extended ones. The consequences of electricity outages for potable water supply can be severe, disrupting supply completely in extreme cases. This is especially true of much of the Gauteng water supply area, which straddles the continental divide, with most of the water supply having to be pumped and raised before it can be distributed to users. The water sector is highly vulnerable and there is no regulation that ensures the continuity of supply due to energy.

A growing concern

Historically, the risk of electricity supply failure did not play a significant role in the design and operation of water supply and distribution systems. In 2010, the introduction of load-shedding prompted the WRC to initiate a high-level study on the effect of electricity interruptions on water supply. A follow-up study, which was recently concluded, explored the implications of this in greater detail and took account of new concerns that have arisen.

The study was based on the preparedness of the City of Tshwane, which makes up a significant portion of

The severe consequences of load-shedding

the Rand Water supply area. Some 80% of the municipality’s water supply is derived from Rand Water and Magalies Water, while the remaining portion is derived from the city’s own sources at Rietvlei Dam, Roodeplaat Dam, along with various dolomitic springs and wells.

The study made use of risk analysis methods, the selection was based on a quantitative approach, and the duration and likelihood of the various hazards identified were estimated based on the available information.

The likelihood of the worst-case scenario (total blackout for 30 days) was found to be highly improbable (1:155-year probability). However, the other scenarios highlighted that there is a lack of or no preparedness of key water supply infrastructure points at the municipal level. Water will stop flowing if there is an extended loss of electricity.

Further, the scenario analyses provided the following insights: •F or short-term electricity disruption events, it is crucial to first ensure that reservoirs and elevated towers are large enough to be able to supply at least two days’ annual average daily demand. Second, reservoir and tower operating rules should be adhered to in order to ensure that water levels are maintained within the fluctuation volume of the reservoirs/towers.

•F or medium- to long-term electricity disruption events, the volume of water stored is less important, since the water stored in reservoirs will almost certainly run out if water is not supplied into the reservoir.

• Backup power generation (both mobile and permanent) will require

ongoing servicing and maintenance – this will have to be incorporated into the city’s water department’s operational and maintenance schedules.

•P roviding emergency storage capacity for sewage inflow in wastewater treatment works is more expensive than providing backup power generation at wastewater treatment works. Emergency storage will not be practical for medium- to long-term duration electricity disruption events.

• The supply and delivery of fuel to the city’s water and sewer pump stations and its water and wastewater treatment works will have to be planned.

•A lternate energy and power generation at wastewater treatment and works can reduce, if not eliminate, the costs associated with standby power. *Jay Bhagwan is the executive manager: Water Use and Waste Management at the Water Research Commission.

M A R/ A P R 2020

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WATER SECURIT Y • OPINION

Why the MASTER PLAN can succeed

C

riticism from within the ruling party suggested that internal communication was flawed, and accusations were made that suggest deep internal cleavages. The controversy itself betrays the existence of internal dynamics at work within the ANC. The real headline-grabbing issue is the growing public resentment, with some cashing in on the anti-government bandwagon by suggesting that water services have deteriorated to a point where they are currently worse than existed in 1994. If true, then this is an indictment on the way water has been managed during our quarter century of democracy.

The reality sandwich

To assess the implications, let us take a bite out of the reality sandwich. The most glaring aspect of the NW&SMP is that it mostly reflects the same old thinking that has dominated the last two decades. The usual noises are made about the need to manage demand better, with some scant reference to new sources of water such as desalination and wastewater recovery. As usual, blame is shifted to the consumer for ‘using too much water’ and a call is made to reduce consumption.

The attention-grabbing aspect is the cost – around R1 trillion, give or take a few rounding errors.

Therefore, the first bite of the reality sandwich arises from that fact that South Africa has been cash constrained since 2014. Foreign direct investment (FDI) expressed as a percentage of GDP became net negative at the time of the Marikana Massacre and has consistently dropped off the cliff. Of historic reference, we saw the same thing happen between 1985 and 1998. That period saw a net negative

18

MAR /APR 2020

FDI value of 5% and it established the background for regime change in 1994.

We, therefore, ought to be very concerned at the trajectory post 2014 because it is fast approaching net negative 30%. This is a serious matter, because it tells us that the economy is in tatters, so the first big question that arises is who will fund the R1 trillion being so glibly touted?

Companies are in dire straits, so profits are down, with a direct impact on revenues to the fiscus. The hostility created by the Bell Pottinger campaign against ‘white monopoly capital’ has done something that we never saw in the past. While the net negative 5% FDI in the decade from 1985 to 1995 was driven by institutional capital outflows, the current net negative 25% is driven by the flight of individual savings.

Trust has been lost in the government and the economy, so it is no longer investible. This means that the fiscus is simply unable to pay for the infrastructure needs touted by the NW&SMP. On the

The National Water and Sanitation Master Plan (NW&SMP) was recently announced, and immediately became embroiled in controversy.

By Anthony Turton

contrary, the fiscal cliff – that moment when civil servants can no longer be paid because of insufficient revenues to the state – will become a very real issue in the short- to medium-term future. Every civil servant ought to become aware of this issue, as it will affect them personally when 40% needs to be lopped off the total government salary and benefits bill.

The minister’s advisor

This brings me to the second key element of the analysis. Minister Sisulu has come under considerable fire because of the appointment of Mo Shaik as a personal advisor. I hold a different view on this matter, because if anyone understands water as a national security risk – the sort of thing that becomes central to regime change when FDI values continue to plummet – then it is Shaik.

WATER SECURIT Y • OPINION

Dr Anthony Turton, professor at the University of the Free State’s Centre for Environmental Management

I worked with him during the amalgamation of the statutory and nonstatutory intelligence structures in 1994/95, where I developed a respect for his insight into national security skills. I have worked closely with him on some strategic matters and can attest to his abilities in that sphere. His appointment is thus an important one in my view, because it signals the fact that government is now beginning to realise the national security risks arising from the collapse of water and sanitation infrastructure.

Shaik’s immediate deployment into an area of festering unrest in the Free State is consistent with this realisation. Knowing him as I do, pubic perceptions aside, if anyone can do what needs to be done, then it’s probably Mo Shaik. We ought to support him, not decry his appointment and bay for his blood.

Water as an economic enabler

This takes us to the second element of the analysis. Toyota has reached out to government with a simple message that, as a company, they understand how to help rebuild a shattered economy. Their experience is rooted in the rebuilding of Japan after the destruction of the Hiroshima and Nagasaki nuclear bombs

that ended the Second World War. The vision they offered is one of economic prosperity for a rejuvenated South Africa, which has now been given a name – the Public Private Growth Initiative (PPGI).

Central to the PPGI is the recognition that water is an economic enabler, so the instruction was given by senior government officials to create a business chamber for those entities involved in the business of water services provision.

Believe it or not, the commercial players in the water sector have never been organised into one coherent body that can bring funders, technology providers and bankable projects together.

This has now been created and is working closely with the National Planning Commission to prioritise a set of key interventions that will kickstart the economy. This is where the NW&SMP comes in. To this end, existing impediments are being removed with the intention of making the water sector investable once again to enable this master plan.

An attainable target

There is no shortage of capital or technology, so, frankly, the R1 trillion is an attainable target, provided that

bankable projects are generated and trust is restored.

This is not the privatisation of water, as some might suggest, but merely the emergence of a new partnership between business, as creators of jobs and generators of taxes, and government that provides the enabling environment for job creation and human development. The lead agency is the Development Bank of Southern Africa, with the full support of the SA Business Water Chamber.

In my professional opinion, this is the game changer that will create an investment platform into the water sector focusing on the rehabilitation of all existing wastewater treatment works, and the emergence of utility-scale seawater desalination projects for all the coastal cities with water-constrained economies.

Implementation will be through a series of special-purpose vehicles designed to protect capital from theft, but also to provide the skills needed to make service delivery sustainable in an invigorated national economy.

This is what I believe will make the National Water and Sanitation Master Plan succeed. Water is an economic enabler and the Business Water Chamber will work with all existing parties to make this happen.

TREATMENT

DESALINATION PLANT BRINGS RELIEF

A newly upgraded desalination plant in the Eastern Cape has brought welcome relief to parts of the droughtstricken region.

The upgraded Albany Coast reverse osmosis desalination plant in the Eastern Cape

A

matola Water contracted Quality Filtration Systems (QFS) to upgrade the Albany Coast reverse osmosis plant at Ndlambe in the Eastern Cape. Completed in eight weeks, Phase 1 of the upgrade increased the plant’s capacity by 1.4 million litres to a total of 3.5 million litres, serving a population of over 11 000 people.

The desalination plant, located between Bushman’s River and Kenton-on-Sea, was opened by Minister of Human Settlements, Water and Sanitation Lindiwe Sisulu in December 2019.

Officials from Ndlambe Municipality, Amatola Water, the local business forum, the ratepayers’ associations and the Kenton Development Forum joined forces to implement a plan that included maintenance and repairing leaks and the Amatola-funded upgrade of the treatment works.

Drought relief

With many rivers in the region running dry, the upgrade of the Albany Coast reverse osmosis plant brought welcome

relief to holidaymakers and residents impacted by water shortages.

“This is the oldest and one of the few facilities in the Eastern Cape that draws water from the ocean via reverse osmosis and converts that water to drinkable World Health Organization-standard water,” said Herman Smit, managing director, QFS. “As one of the most experienced membrane technology suppliers in South Africa, we were extremely proud to be selected by Amatola Water to provide the much-needed water for this area in the Eastern Cape,” he added.

The plant was originally built in 1982 and became the first desalination plant in South Africa. Amatola Water has allocated R80 million for the plant to be upgraded.

in emergency drought alleviation for cities and towns.

Along the coast, this will take the form of desalination, while inland users can take advantage of wastewater reuse. Both these applications require speciality membrane plants including ultrafiltration and reverse osmosis.

Alternative solutions

Smit believes that small- to medium-sized membranebased plants delivering up to 5 million litres per day will play a major role

Minister of Human Settlements, Water and Sanitation Lindiwe Sisulu with Musa Ndlovu, director, QFS, at the opening of the plant

L to R: QFS’s Werner Diener, Shawn Chaney and Justin Wilmot testing the water at the upgraded plant

TREATMENT

IS CHLORINE CAUSING MORE HARM THAN GOOD? One of the most common methods of treating drinking water – chlorination – has been found to produce toxic by-products when mixed with phenols.

PHENOLS

CHLORINE

TOXIC BYPRODUCTS

When phenols mix with chlorine, hundreds of unknown, potentially toxic by-products are formed Credit: Marissa Lanterman/Johns Hopkins University

R

esearchers from Johns Hopkins University, in collaboration with the University of California, Berkeley and Switzerland, have published new findings that show that the chlorine treatment of drinking water may unintentionally be causing harm.

Phenols – chemical compounds that occur naturally in the environment and are abundant in personal care products and pharmaceuticals – are commonly found in drinking water. The research, published in Environmental Science & Technology, shows that the mixing of phenols and chlorine creates numerous by-products.

Unfortunately, current analytical chemistry methods are unable to detect and identify all these by-products, some of which may be harmful and have long-term health consequences. “There’s no doubt

that chlorine is beneficial; chlorination has saved millions of lives worldwide from diseases such as typhoid and cholera since its arrival in the early 20th century,” says Carsten Prasse, an assistant professor of environmental health and engineering at Johns Hopkins University and the paper’s lead author.

“But that process of killing potentially fatal bacteria and viruses comes with unintended consequences. The discovery of these previously unknown, highly toxic by-products raises the question of how much chlorination is really necessary.”

The study

In this study, Prasse and his colleagues employed a technique commonly used in the field of toxicology to identify compounds based on their reaction with biomolecules like DNA and proteins. They added N-alpha-acetyl-L-lysine, which is almost identical to the amino acid lysine that makes up many proteins in our bodies, to detect reactive electrophiles.

Previous studies show that electrophiles are harmful compounds that have been linked to a variety of diseases.

The researchers first chlorinated water using the same methods used commercially for drinking water; this included adding excess chlorine, which ensures sufficient disinfection but also eliminates harmless smell and taste compounds that consumers often complain about. After that, the team added the aforementioned amino acid, let the water incubate for one day and used mass spectrometry analysis to detect the electrophiles that reacted with the amino acid.

The experiment found the compounds 2-butene-1,4-dial (BDA) and chloro-2butene-1,4-dial (or BDA with chlorine attached). BDA is a very toxic compound

and a known carcinogen that, until this study, scientists had not detected in chlorinated water before, says Prasse.

Alternative treatment methods

While Prasse stresses that this is a labbased study and the presence of these novel by-products in real drinking water has not been evaluated, the findings also raise the question about the use of alternative methods to disinfect drinking water, including the use of ozone, UV treatment or simple filtration.

“In other countries, especially in Europe, chlorination is not used as frequently, and the water is still safe from waterborne illnesses. In my opinion, we need to evaluate when chlorination is really necessary for the protection of human health and when alternative approaches might be better,” says Prasse.

“Our study also clearly emphasises the need for the development of new analytical techniques that allow us to evaluate the formation of toxic disinfection by-products when chlorine or other disinfectants are being used. One reason regulators and utilities are not monitoring these compounds is that they don’t have the tools to find them.”

Other authors on this study include Urs von Gunten of the Swiss Federal Institute of Aquatic Science and Technology and David L Sedlak of the University of California, Berkeley.

“The discovery of these previously unknown, highly toxic by-products raises the question of how much chlorination is really necessary.” Carsten Prasse M A R/ A P R 2020

21

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SLUDGE MANAGEMENT When wastewater sludge is incinerated or disposed of at landfill, we are are both wasting a valuable resource that could be recycled for use on agricultural lands and potentially polluting the air and groundwater.

By Danielle Petterson

A

s all aspects of society are being pushed to move from a linear to a circular economy, it is important to consider how the wastewater treatment process can follow a similar approach. Professor Eyob Tesfamariam, University of Pretoria, argues that treated wastewater sludge can serve as a source of organic matter to reclaim degraded lands and a source of macroand micronutrients to agricultural lands, boosting food production while providing a sustainable solution for sludge management.

In doing so, Tesfamariam believes we can address multiple Sustainable Development Goals (SDGs), including: • SDG 2 (zero hunger) – by boosting crop production • SDG 3 (good health and well-being) – by adding micronutrients back into our food • SDG 6 (clean water and sanitation) – by improving raw water quality • SDG 12 (responsible consumption and production) – by restoring degraded land • SDG 15 (life on land) – by sequestering more carbon into the soil.

A model for sludge in agriculture For decades, most commercial famers have been adding only three macronutrients to their soils: nitrogen, potassium and phosphorus. Little attention was given to the status of soil micronutrients, which have been exploited for decades or even centuries. As a result, most cultivated crops are deficient in micronutrients and need fortification for human consumption. Treated wastewater sludge is rich in micronutrients and could serve as a source of micronutrients as well as the most commonly applied macronutrients, explains Tesfamariam.

The use of sludge in agriculture

Sludge has been used in agriculture in South Africa for many years, and South Africa has developed very strict guidelines in this regard. Sludge may only be used on agricultural lands if the pollutant concentration, sludge stability and status of pathogens all fall within acceptable limits.

The current South African Sludge Guideline states that sludge that qualifies for agricultural use should be applied according to crop nutrient requirements at a maximum application rate of 10 t/ha/year.

However, Tesfamariam questions whether we should stick to the maximum application guidelines. This is because different sludge

has different release rates, and different crops require varying amounts of nutrients within different ecological zones. This has been proven by a study that Tesfamariam has been working on for the past 15 years.

“We’ve done a lot of field work and laboratory studies and found that activated sludge has got the highest nitrogen release rate, while anaerobically digested paddy-dried sludge has much lower release rates.

This means the amount of nitrogen that will be available to the plants will be completely different. It is clear that you M A R/ A P R 2020

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SLUDGE MANAGEMENT

cannot apply the same rate for different sludge types,” he explains.

Another study by Tesfamariam and his colleagues also looked at sludge degradation and nutrient release rates across South Africa’s six different agro-ecological zones and found that the amount of nitrogen released differs between zones. The release rate is far lower in arid zones than in humid zones.

SARA Platform

Taking into account the interaction between the soil type, the sludge release rate and crop nutrient requirements, Tesfamariam and his team have developed the SARA (sludge application rate advisor) platform, which integrates these factors to provide site- and cropspecific recommendations.

To do this, the platform requires the user to input a variety of data points, including: 1. S ludge classification parameters (faecal coliforms, helminth ova,

pollutant concentration and stability class) to determine whether it is fit for agricultural use 2. S ludge parameters (nutrient content such as N, P, K, water content , etc.) to determine the fertiliser value of the sludge 3. F arm parameters (location, soil type, nutrient composition of the soil, crop to grow, etc.).

Using this data and the Fertilizer Handbook (which is built into the model), the model predicts the nutrient requirements for the specific crop in the specific area. It also predicts the amount of nitrogen likely to be released in that agro-ecological zone based on the type of sludge.

Taking all of this into account, it provides a recommendation rate for sludge application.

Importantly, the model takes into account the nutrients already in the soil in order to maximise your sludge application rate per field and minimise environmental impacts through nitrate leaching.

It also informs you how much potassium fertiliser you need to add, as sludge is not a good source of potassium.

Based on input data, the model will determine the period after which you should expect a heavy metal buildup and the type of heavy metals that will reach a threshold level. Lastly, a cost-benefit analyser determines the economic feasibility of using sludge based on transportation and spreading costs, using commercial fertiliser as a benchmark.

Although the SARA platform is still a work in progress, Tesfamariam plans to make it freely available through the Water Research Commission once complete.

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SLUDGE MANAGEMENT

Beneficiating sludge to the benefit of utilities

The by-product of wastewater treatment – sludge – is considered a problem for most utilities. However, partnership opportunities can be developed that allow private companies to turn that sludge into valuable fertiliser, saving municipalities time and money.

I

n most instances, sewage sludge is seen purely as waste which is to be disposed of at the lowest possible cost.

Conventional disposal by landfill or crude agricultural application incurs significant and increasing costs and represents serious ecological hazards.

Today, as rapid urbanisation increases wastewater volumes, financially strained utilities often follow such unsustainable disposal strategies with minimum compliance.

As a result, utilities often seek to dispose of sludge in land applications at the highest possible application rate, as close as possible to the point of generation, complying with the minimum level of compliance possible.

Sludge for agriculture

If correctly treated to A1a requirements, sludge can be hugely beneficial to agricultural land. Biosolids from the wastewater treatment processes consist almost entirely of dead and decomposed microorganisms. Once stabilised and processed, the resultant product is rich in humus and humic substances,as well as plant macroand micronutrients.

The organic fertiliser that can be produced offers many measurable,

positive effects on crucial soil processes. It improves soil structure through the formation of aggregates, thereby also improving gas exchange and soil permeability. The material retains up to 20 times its own mass in water, preventing drying and shrinking of soils, while also dramatically increasing cation exchange capacity and the formation of chelates.

However, from a nutrient perspective, excessive amounts of biosolids are often applied when municipalities opt for the highest possible application rate as a means of lowering costs. According to Francois Burger, managing director, Agriman, biosolids have far more value if applied at the right rate, in the appropriate relation to other nutrients, and in the right physical format.

Compliance

“Unfortunately for sludge producing authorities, the agricultural industry has developed into a highly scientific environment with the current trend of precision farming practices, which requires any new entrants to the market to provide all the services in the value chain,” says Burger. This includes agronomical advice, evaluation of chemical soil analyses, prescription of fertiliser programmes, formulation and blending of prescribed mixes, aftersales service and problem-solving.

Producers of fertiliser products to be used in agriculture need to comply with legislation (Fertilizers, Farm Feeds, Seeds and Remedies Act (No. 36 of 1947)) as well as standards regarding physical properties – e.g. density,

particle size, hardness, chemical stability and flow. To compete in the conventional fertiliser market, the product must be fit to be applied by conventional equipment and implements.

Aiding municipalities

Although sludge is often considered a burden, companies like Agriman partner with municipalities to transform their sludge into fertiliser for the agricultural industry. The products and services developed by Agriman for the beneficial utilisation of wastewater sludge cover the entire value chain, from sludge dewatering right through the process of fertiliser manufacturing and sales, up to aftersales service to the farmer in his fields.

The benefit to the local authority is that they bear no responsibility for the ‘waste’ product once it leaves the gate, as the product becomes a registered fertiliser. They do not incur any transport costs and, due to the value proposition, the distribution radius of the product exceeds the borders of our country. This, says Burger, is a true example of a viable circular economy.

“Municipalities should focus on producing a top-quality sludge, investing in proper on-site dewatering and drying facilities. Then they can pass their sludge on to organisations like Agriman to produce fertiliser products, without incurring the everincreasing cost of off-site disposal,” he concludes.

M A R/ A P R 2020

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SLUDGE MANAGEMENT

MAKING CO-DIGESTION FEASIBLE The Western Cape has called for a total ban on organic waste to landfill by 2027, with a target of 50% by 2022. As other municipalities follow suit, the case for codigestion with wastewater sludge is worth considering.

By Danielle Petterson CHP plant at the Northern Wastewater Treatment Works

S

outh Africa produces around 10 million tonnes of food waste per year.

According to a 2017 WWF report, titled Food loss and waste: Facts and futures, the cost of energy embedded in this food waste is approximately R1 billion per annum.

The energy wasted every year for producing food that is never consumed is estimated to be able to power Johannesburg for roughly 16 weeks.

But what if that food waste were turned into energy?

The opportunity exists to significantly increase energy production at wastewater treatment plants through co-digestion with food waste.

Creating efficiencies

Many of the large wastewater treatment plants in South Africa’s metros contain anaerobic digesters.

They form part of the process to treat sewage sludge and generate biogas, which can in turn be used to generate combined heat and power (CHP).

Significant opportunities exist to boost CHP production at these

26

MAR /APR 2020

plants by adding organic waste to the anaerobic digesters. Organic waste with a high organic fraction can significantly increase biogas production, says Karl Juncker, owner, WEC Projects. This has been proven at the Northern Wastewater Treatment Works in Johannesburg, where ice cream waste was added to the digesters and more than doubled biogas production with the same digesters.

The key is to have consistent sources of organic waste, as big changes in consistency can be problematic.

If municipalities were to approach surrounding businesses, regular sources of consistent organic waste could be secured. “Wastewater sludge is relatively low in organics. Adding 20% volume of high organic sludge would be fantastic in a wastewater digester. With consistent organic addition, you can double or even triple your biogas production,” says Juncker.

He uses Johannesburg Water as an example. The utility requires 17.18 MWe to run its treatment plants with the potential of generating 9.58 MWe from biogas produced in the

anaerobic digestion process. If the utility were to incorporate organic waste, it has the potential to meet and even exceed its energy requirements.

Prohibitively expensive?

Organic waste-to-energy has often been touted as too expensive, largely because landfilling is considered ‘prohibitively cheap’. However, as municipalities are faced with diminishing landfill airspace and organic diversion targets, organic waste-to-energy may present an attractive alternative.

In terms of alternative energy production, waste-to-energy is typically labelled as far more expensive than solar or wind power.

However, Juncker points out that wind and solar have limitations. Although solar may appear cheaper per kW produced, there are only four to five hours a day for peak solar energy production. It is also difficult to store this energy and bad weather affects its productiveness. Wind power has similar limitations. Large-scale wind and solar are also typically limited to decentralised locations far from where the energy requirements are.

210 kg

per person of food waste is generated per year

1/5th

Biogas, on the other hand, can be easily stored in gas holders and its peaks manipulated to suit requirements, allowing for continuous energy production. As a result, Juncker believes that, per hour, the costs work out to be similar.

The infrastructure costs are the largest expense when it comes to waste-to-energy. By utilising existing infrastructure at wastewater treatment plants in a co-digestion facility and simply adding engines, costs can be significantly reduced, making it far more economically viable.

Such partnerships could also be used to reduce the overall costs of wastewater sludge treatment and improve environmental compliance for municipalities.

Other advantages

of SA’s water is used for food that is wasted

which can be sold to the agriculture sector as fertiliser. Biofuels and biogases could also be created for use in vehicles.

Water is another by-product that can be treated and reused. Industries that generate organic waste are typically high water users and could be supplied with water in exchange for their waste. Abattoirs are perfect operations for partnerships, says Juncker. They generate a large amount of organic waste, which can be fed into digesters, and require heat, power and water for their operations, which can be produced through the biodigestion process.

The process also creates an inherent reduction in emissions, offsetting what would be created if that organic waste were sent to landfill or composted. This opens opportunities for carbon credits. “There is a big benefit to adding high organic waste to stimulate biogas production. If your digesters operate correctly, you are guaranteed a good product,� concludes Juncker.

By converting organic waste to biogas for energy production, municipalities can help contribute to the circular economy. The power generated can be used to run the wastewater treatment plant while the heat can be used in the biodigesters or sold back to industry for heating requirements.

There also exists the opportunity for nutrient removal. The digested sludge and organic waste are high in nitrates and phosphates, Sludge drying

Biosolids produced via the biodigestion process

STORMWATER

Harvesting a valuable resource When Cape Town was faced with the possibility of running out of water, attention turned to rainwater harvesting. Now studies are under way to determine the viability of urban stormwater ponds as water resources for the city.

By Neil Armitage*

T

he 2000 edition of the ‘Red Book’ – i.e. the CSIR Guidelines for Human Settlement Planning & Design – defines stormwater as mere “run-off ”’ and describes it as “the common enemy that each property owner may fight... or control” essentially by any means available, as long as there are not obviously detrimental consequences to the neighbours.

Nothing could be further from the truth. The revised ‘Red Book’ (CSIR, 2019) more accurately defines stormwater as: “rainwater or melted snow that runs off

streets, lawns and other sites... [and it] should be regarded as a resource.”

Like any other resource, it can be used or abused.

Changing attitudes

The Day Zero crisis in Cape Town that came to a head in 2018, where the city came perilously close to running out of potable water, heavily underlined the fact that the days of considering stormwater as ‘the common enemy’ are now past. Even in the driest of years, the metro receives far more water in the form of rainfall than it ever supplies to its residents. However, almost all

One of the proposed experimental sites for Future Water’s study

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water supply comes from the ‘Big Six’ reservoirs situated in the Hottentot Holland Mountains east of the city.

Meanwhile, the run-off in the city – increased in recent years by the relentless development that seals the surface – is largely discharged into the sea, taking along with it all sorts of pollutants including nutrients, heavy metals, trash and even sewage.

The threat of dry taps rapidly changed attitudes towards rainwater in Cape Town. Purveyors of rainwater tanks did roaring business, as the more affluent citizens in the leafy suburbs queued up to have them installed in their properties – at great expense – so at least they could secure some additional supply. They quickly found that even the largest tanks cannot hold enough roof water to see most properties through Cape Town’s long, hot, dry summer.

In most instances, drilling well-points/ boreholes gave a better return – but, even then, the water table began to drop owing to excessive withdrawal.

There are several lessons to be learnt here: rainwater is hard to store in quantity at household level; groundwater needs to be replenished, if it is to serve as a reliable water resource; and stormwater should not be abused (through urban pollution) and ignored – except when it is a threat to property.

STORMWATER

Harnessing rainwater

In 2015, the Water Research Commission of South Africa awarded a contract to the Urban Water Management research unit (now the Future Water Institute) at University of Cape Town (UCT), entitled ‘The viability of urban stormwater ponds as water resources in Cape Town’.

The study looked at the Zeekoe Catchment that lies between Cape Town International Airport and False Bay, which conveniently overlies a large unconfined sandy aquifer.

The objective was to see whether stormwater could provide a reliable supply of reasonably cheap water in enough quantity to make a difference to Cape Town’s water supply needs.

Key was the idea of repurposing some of Cape Town’s 800-odd stormwater

South Africa

control ponds, which are mostly dry detention ponds for the sole purpose of reducing downstream flood levels. Two important research questions were: 1. Would it be better to store the water above ground in the ponds – suitably modified for maximum water retention – or below the ground in the aquifer?

2. Would it be better to save on treatment and supply ‘secondary’ water uses only – e.g. watering of gardens and flushing of toilets in areas close to the ponds – or treat to potable standards and distribute through the existing water reticulation system?

The study, which was completed in 2018, showed categorically that, for the study site at any rate, it was better to store the water in the aquifer and, when required, treat to potable for distribution through the existing water reticulation system. The estimated cost was comparable to that of groundwater extraction – something the City of Cape Town is beginning to do in the area in any case – and not that much more than the cost of

bringing water in from the reservoirs in the mountains.

Stormwater harvesting in this one catchment alone, which only covers some 4% of the metro, could realise approximately 3% of the city’s current potable water demand – on top of the 6% potentially available from the natural recharge of the aquifer.

Questions still, however, remain regarding the practicalities of turning dry detention ponds into periodically wet infiltration ponds – particularly in low-income areas where the water quality is poor, and safety and security are major issues.

Thankfully, Future Water at UCT has been awarded funding from the Danish government through Danida to, inter alia, study this in conjunction with colleagues from the University of Copenhagen. This is a three-year study that will be complete in 2022.

*Professor Neil Armitage is the deputy director and co-founder of the Future Water Institute at the University of Cape Town.

WATER LOSS

With the transition to smart cities, opportunities arise to harness smart technologies to reduce water losses and better manage all aspects of the water network.

W

ith the rise of the Fourth Industrial Revolution, engineers are turning their attention to smart cities: areas that harness the internet of things (IoT), making use of electronic sensors to collect data that can be used to manage assets, resources and services efficiently.

Smart cities will feature a range of disruptive technologies, including smart metering, automated meter reading (AMR), advanced metering infrastructure (AMI), cloud computing, real-time hydraulic modelling, artificial intelligence (AI) and more.

When it comes to water, smart cities should at least feature AMI, says Dr Alexander Sinske, senior executive, GLS Consulting. AMI offers numerous benefits by supporting strategies to address water scarcity and water conservation.

It allows municipalities to better understand water consumption and

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GETTING SMART ABOUT LOSSES demand patterns, while reducing non-revenue water by detecting water losses and improving the management of water production, storage and distribution. It also enhances customer service by facilitating more accurate billing and efficient administration.

Rise of the water digital twin

The use of digital twins is also growing in the infrastructure space. A digital twin is a digital replica of a physical entity. Digital twins integrate elements including IoT, AI, machine learning and more to develop models that can be continuously updated and maintained to be truly representative of the real world.

Achieving this in the water field requires having extensive monitored network data available for calibration and validation, together with high-quality information, such as customer demands and weather forecasts. In turn, the digital twin can provide a very good picture of what has happened, what is happening now, and what will happen in the future, explains Sinske.

Building a smart city using Wadiso

Pilot project

GLS recently undertook a pilot project incorporating AMI and other smart city elements with the view of creating a water digital twin that would assist with reducing water losses.

This pilot system integrates diverse systems including time series data from several web services, as well as extended period hydraulic models using GLS’s own Wadiso™ software.

The base functionality of the system is to highlight and summarise key information, such as showing critical meter status and historic graphs as well as highlighting sensors that have stale information. It also links data from hydraulic models or system schematics based on GIS and performs advanced post-processing.

The range of post-processing functions is broad, incorporating sensor data integrity checks, the accurate calculation of dam storage volumes, multiple aggregation of sensors from different vendors, and interaction with hydraulic models.

Where the system transitions towards a digital twin is in its ability to simulate models with near real-time data. This system follows a process of cleaning demand data, resampling and smoothing of data, loading time simulation patterns, and calibrating and incorporating other auxiliary time series. Thereafter, it can analyse the past, confirm present events and attempt to predict the future.

When it comes to reducing water losses, the system could identify slow leaks through routine data analysis using machine learning, as well as

WATER LOSS

Typical catastrophic pipe burst

Dr Alexander Sinske, senior executive, GLSÂ Consulting

instantly locate large leaks as they happen through pressure sensors and smart algorithms.

Case study example

GLS applied the software in a pilot study to a conceptional Western Cape town, using an existing time simulation model and real telemetry data sourced from neighbouring towns.

According to Sinske, the focus was first to calibrate a synthetic model using demand scenarios from different seasons. Thereafter, an analysis of an existing event was performed, and finally the prediction of a future event.

Raw telemetry outflow data for an informal settlement reservoir in a critical summer week was sourced. The data showed typical problems such as strange spikes at specific times and gaps in measurement, which were auto-corrected. GLS could also simulate water-level fluctuation for the reservoir using a synthetic demand pattern based

Comparing ambient temperature to demand patterns

on land-use data, average annual demand, and expected peak factors.

This is used as a fallback where no telemetry data is available.

In another area, the resulting time simulation demand pattern showed a typical morning and evening peak matching a more formal demand pattern, as expected. The synthetic pattern for peak demand matches telemetry data, but the base flow was different and required correction.

Sinske explains that, for some demand patterns, such as an informal area, the ambient temperature can be a good indication of predicted demand.

Here, the demand follows the ambient temperature closely and can be used as a proxy for predicting near-future demand, such as for the week ahead.

Observing a catastrophic event in telemetry data and on the map

For other demand patterns, such as a mixed-demand area, temperature is not a good proxy.

GLS also recorded a catastrophic incident in terms of the water level of one reservoir. This could in turn be simulated by two interruptions on the feeder line to the reservoir. Although the exact rules controlling the reservoir filling have not been correctly captured, the reservoir runs empty in about 40 hours, as predicted.

Sinske is confident that the work to date will go a long way in smart water management. Future work will look to perform other analyses, such as how demand usage patterns changed after droughts, and improved machine learning.

GLS would like to integrate telemetry sources from more online providers and get utilities to install more bulk and zone meters, as well as roll out affordable IoT meters to include end-user monitoring points. “If we can achieve this and incorporate concepts of machine learning to analyse patterns, we will soon be able to model the future far more accurately, by better understanding the past,� concludes Sinske.

NN/F EEB MJJAAR/ AP RB 2020 2020 /F 2020

31 31

BIOLOGICAL CONTROL

Bugs beat back water hyacinth Biological control agents are turning the tide in the war against water hyacinth at Hartbeespoort Dam.

T

he 95-year-old Hartbeespoort Dam has been plagued by water hyacinth since the 1970s, causing serious water quality issues. Now, millions of insects are rapidly destroying the hyacinth without the use of herbicides.

Effective biological control

Efforts to control the water hyacinth at Hartbeespoort Dam have been under way for decades and include the use of herbicides, mechanical and manual removal, and biological control. By far the most sustainable and environmentally friendly option, biological control is a long-term, natural process that aims to reunite invasive species with their natural enemies.

According to Professor Julie Coetzee from the Centre for Biological Control (CBC) at Rhodes University, waterhyacinth-specific insects (biocontrol agents) have been deployed at Hartbeespoort Dam since the 1980s, but

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their populations have been inhibited as a result of periodic herbicide application and cold winter frosts.

Currently, six different kinds of insects can be found on the hyacinth at Hartbeespoort, but most of the success in destroying hyacinth can be attributed to the planthopper (Megamelus scutellaris) that has been continuously and intensively introduced since last year. The CBC, together with Pecanwood College and Mountain Cambridge School, and in consultation with local schools and concerned citizens, including The Harties Foundation, embarked on a mass release campaign over the last year, releasing tens of thousands of planthoppers monthly.

Coetzee and her team continue to monitor these populations monthly and she believes that the lack of herbicide application over the last two and a half years has allowed the insects to build up their populations to a level where plant death is noticeable. The results on the

dam are significant, with a 3% drop in hyacinth cover recorded in just a week.

No evidence of herbicides

Coetzee also allays fears that hyacinth death is the result of herbicide application.

“I know that there is a lot of speculation around the alleged spraying of the water hyacinth plants, with various theories on why the plants were sprayed. People find it hard to believe that the browning of the plants could actually be due to biological control agents,” says Coetzee.

“While we don’t have evidence that the plants weren’t sprayed, there is so much evidence pointing towards biological control, as opposed to herbicides.”

Coetzee points to the fact that the stems of the plants are green and the bugs covering the plants are still alive – neither of which could be the case if herbicides had been used. Although the plants are still green, she noted significant biological damage, which will eventually cause the plants to die.

Past problems

Frederick Botha, technical advisor, Hartbeespoort Rehabilitation Steering Committee, explains that the water quality in the Hartbeespoort Dam began to noticeably decline in the 1960s.

Today, the effluent from 11 wastewater treatment plants feeds into the dam via a number of rivers, often carrying high phosphate and sediment loads.

Although the legal limit for phosphate in effluent is 1 mg/ℓ, this is often exceeded, resulting in eutrophication.

These high phosphate levels feed water hyacinth and, in 1977, the dam was invaded by these alien plants, which covered 70% of the dam’s 2 000 ha surface area.

At the time, the Department of Water Affairs took action, spraying the hyacinth with herbicides, resulting in roughly 40 000 tonnes of plant matter sinking to the bottom of the dam (fresh water hyacinth contains 91% water). However, this posed a new problem: the plants began to decompose aerobically as well as anaerobically, releasing biomass nutrients into the water and greenhouse gases into the surroundings. The result was an explosion of cyanobacteria, which had never been prevalent

in Hartbeespoort Dam prior to this.

During the 1980s, the cyanobacteria caused a number of blue-green algal blooms and in March 2003, an emergency was declared when the algae formed a hyper scum, covering a large portion of the dam surface.

When the cyanobacteria begin to fight for oxygen, they release a cyanotoxin to kill each other.

This toxin is not removed by most water treatment plants and can attack the liver. Botha describes it as the biggest problem for drinking water safety on Hartbeespoort Dam. Since then, a great deal of effort has been put into controlling the spread of water hyacinth and preserving water quality in the dam.

Long-term biological control

Coetzee explains that the water hyacinth is unlikely to ever completely disappear from the

dam, with small amounts likely to remain off the shores. The biocontrol insect populations will decrease as the plants die but should keep the small populations of the plants in check.

The insects, such as the Neochetina weevil and planthopper, have been thoroughly studied in South Africa and elsewhere, ensuring they are safe and effective.

Because they only feed and reproduce on water hyacinth, no other plants will be affected.

However, Coetzee cautions that the hyacinth may recover in the spring as a result of a cold winter and high nutrients, as well as seeds in the sediment.

Nonetheless, CBC will continue to release insects and monitor their populations to ensure they build up faster than they would on their own, ultimately ensuring long-term control of the water hyacinth.

SANITATION

Making products from human waste Our current global resource model is linear in nature; it involves take-use-dispose. This model can lead to wastage and has little emphasis on resource optimisation, writes Dr Sudhir Pillay*.

W

ith the consumption of global resources expected to rise due to increasing population size, new ways of resource optimisation are required to ensure we do not consume beyond what we have.

One of the new economic models that has been gaining traction is based on circular economy principles.

In this approach, the continual and/ or efficient use of resources through reduction, reuse and recycling is promoted. Circular economy models attempt to create a closed-loop system, minimising the use of resources and the creation of wastes.

The current approach

In sanitation, the current take-use-dispose models are wasteful. We routinely use two modes of sanitation. In urban centres, flush toilets are used. This technology uses 6 to 9 litres of drinkable water – of which there is a limited supply – to move our waste through sewers until it reaches a wastewater facility.

Once at a treatment facility, selected constituents in the wastewater are consumed by microorganisms.

Eventually, these microorganisms grow to a point where the tanks that hold them need to be emptied. In South Africa, the majority of this ‘waste’ ends up at land disposal sites.

Outside of sewered areas, dry sanitation technologies are used. While saving

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on water, the technologies fill up with human waste, becoming a thick, sticky paste called faecal sludge. This needs to be emptied and is then transported to a centralised location for disposal – usually at a land disposal site.

Land disposal sites can only handle a certain amount of sludge disposal and many can fill quickly if the balance is skewed more towards disposal than degradation. Growing population sizes mean that ever-growing sanitation waste volumes need to be treated.

A new approach

With the number of land disposal routes expected to become limited, circular economy principles are being considered as a sustainable option to manage human faecal waste. At the Water Research Commission (WRC), research is being undertaken to examine if the resources contained in human faecal waste can be repurposed into products of economic value, thereby introducing circular economy principles into the management of human faecal wastes.

To understand what products of economic value can be extracted from human faecal waste, one needs to understand what is contained in our urine and faeces. Water makes up the largest fraction of both of these.

Urine contains around 90% water.

It also contains essential plant macronutrients (nitrogen, phosphorus

and potassium) that are routinely used in fertilisers. If urine and faeces can be separated, there exists an opportunity to harvest and recycle these nutrients.

In comparison, around two-thirds of our faeces is water. The remainder consists of solid material, with organic material representing the highest fraction followed by bacterial biomass, protein or nitrogenous matter, carbohydrate or any other non-nitrogenous undigested plant matter, and undigested lipids.

These constituents can be extracted and properties changed through innovative engineering processes to manufacture products of economic value.

Extracting value from waste

Large volumes of urine can cause eutrophication of water bodies, which leads to oxygen depletion and subsequent adverse aquatic life effects. Several innovations have been demonstrated in South Africa that seek to repurpose urine. If urine can be separated from human waste streams, there exists an opportunity to repurpose it and prevent downstream pollution challenges.

At the University of KwaZulu-Natal, Professor Ademola Olaniran has shown that it is possible to convert urine through innovative engineering processes into struvite – a phosphate mineral that can used as a fertiliser.

Olaniran’s research also looked at the health and safety implications of reusing

GREY WATER

Bio-brick formation from urine undergoing stress testing

urine-derived struvite for horticultural purposes.

At the University of Cape Town, Dr Dyllon Randall has been exploring the production bio-bricks from urine. Randall’s research collected urine from men’s urinals and fed this to selected bacteria, producing a gelling-like substance that binds masonry sand together to form a bio-brick. The research first aimed at illustrating the possibility; new research is aimed at optimising the processing of products and developing the business models to scale up the innovations.

The capabilities for repurposing faeces have also been demonstrated. By turning our excreta into products of economic value, there is an opportunity to generate additional revenue streams from products that would otherwise be disposed of.

Worldwide, many wastewater works are converting their plants into resource recovery facilities. The process used involves anaerobic digestion that converts the fermenting waste into biogas. This biogas can be scrubbed, cleaned and reused for heating or generating electricity. More recent advancements involve producing renewable fuel options for motorised vehicles, which can cut diesel usage and greenhouse gas emissions.

Several car manufacturers have noted the possibility. Toyota has developed a concept car that runs on hydrogen fuel cells using fuel derived from faecal waste. In South Africa, BMW has been using a similar process at its facility in Bronkhorstspruit to supplement its electricity demand using cow manure and other organic wastes. This indicates that South Africa has the capability to undertake such engineering projects and there exists the potential to convert our wastewater treatment works into fuel generation centres.

M AR/ APR 2020

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SANITATION

Faecal waste repurposed into briquettes (Credit: Water for People Uganda)

Creating a business case

Where there is potential for revenue, businesses will follow. In sub-Saharan Africa, large populations have no access to toilets. New socially driven business models have sprouted in Kenya and Uganda to provide toilets, collect the human faecal wastes and convert this into economic products.

In Kenya, a social enterprise called Sanivation provides mobile toilets at households and the waste is collected twice a week. This waste is then taken to a resource recovery facility where the high temperatures in solar concentrators sterilise the waste, which is then processed further and turned into charcoal briquettes that are used as fuel for burning.

In Uganda, Water for People has been using a similar approach to convert human sanitation waste into charcoal briquettes. As part of the business model, Water for People investigated the quality and market potential of the briquettes produced compared to charcoal, which is used for household heating purposes. The investigations revealed that sanitation-derived briquettes can deliver the same fuel value as charcoal.

Other processes being demonstrated involve the conversion of human faecal waste into protein feeds or commercial oils. While several of these concepts have been demonstrated in South Africa through WRC research,

it has yet to sprout resource recovery business models linked to service delivery, as has happened in Kenya and Uganda.

With many of these concepts having shown to be successfully demonstrated, the next stage is how we translate research into practice and develop the appropriate business tools for municipalities to utilise as part of their operations – including working towards user acceptance of alternate fuels, price-competitiveness among market-related products and reliability of product quantity and quality.

*Dr Sudhir Pillay is a research manager at the Water Research Commission.

SANITATION

AWARD-WINNING dry sanitation Did you know that just one Enviro Loo can save up to 420 000 litres of water annually?

S

aving water has become a top priority as a burgeoning population and the effects of climate change place an everincreasing strain on the world’s precious water resources.

Enviro Loo is a completely off-the-grid toilet system that operates using the natural resources of heat and wind energy through an aerobic, separating and odourless process of evaporation and dehydration, breaking down human waste to a dry, stabilised material that is roughly 5% of its original content.

Complete system

Because it is a containerised system, the Enviro Loo does not leach harmful waste into the surrounding landscape, thus protecting water and food resources.

The ceramic toilet bowl (much like that of a standard waterborne toilet) is featured in a standard and junior size, making it safe to use and easy to clean.

The Enviro Loo, a wholly South Africandesigned and -manufactured product, is not only friendly to people but also to the environment, with its non-polluting, sustainable properties.

All Enviro Loo toilets are constructed using high-quality materials.

Various models accommodate different user and usage requirements per unit, whether a single person, a family of four or ten, a communal toilet for use of up to 30 people, or as many as 40 people. There is also an Evaporative Urinal Tank model with connections for up to four ceramic urinal bowls.

Long-term interventions

It has become clear that simply constructing toilets is a short-term solution. Dry sanitation systems (as for waterborne toilets) need to be sufficiently maintained to avoid falling into disrepair and being rendered unhygienic and unusable.

Each new Enviro Loo unit comes with a two-year service and maintenance programme. Local community members are trained and employed as janitors and maintenance technicians to ensure the ongoing efficient operation of the units.

This also serves to meet the goal of the Enviro Loo philosophy of uplifting local communities by easing unemployment.

Enviro Loo is manufactured in South Africa using locally sourced materials and

components, making it an affordable option. Since the South African government’s launch of the Sanitation Appropriate for Education (SAFE) project in 2018, 5 500 Enviro Loos have been installed in schools, with a further 600 units specified as part of this initiative.

Just one Enviro Loo industrial model can save up to 460 000 litres of water and break down 5.5 tonnes of waste annually.

Award-winning system

In 2017, Enviro Options attained ISO 9001:2015 accreditation for its manufacturing practices and Fit for Purpose Certification for its products.

The Enviro Loo has been the recipient of many awards, both in South Africa and internationally. These include the 2019 Enviro-Paedia EcoLogic Award for Water Saving, and the 2017 Frost and Sullivan Best Practices Award for the Southern African Dry Sanitation Company of the Year, putting Enviro Loo at the forefront of the dry sanitation industry.

M A R/ A P R 2020

37

INDUSTRIAL WATER

INNOVATIVE REPLACEMENT SOLUTION

T

he Sappi Tugela Mill is one of the company’s oldest purposebuilt mills producing container board and lignosulfonate for local and export customers. A pipeline conveying treated process water from the mill to a dedicated discharge point on the Tugela River needed replacing, as it had reached the end of its design life and was showing signs of fatigue and potential failure due to degradation of the steel pipe wall.

In April 2018, Sappi went out to tender for the replacement of the pipeline.

The replacement pipeline needed to be constructed not more than 3 m from the existing pipeline and all works were to remain within the provided 8 m servitude.

The existing pipe needed to remain in operation until the new installation was complete, and all route markers, manholes and related structures were to be reinstated as part of the project.

Having reached the end of its life, an innovative solution was needed to replace a 3.5 km, 1 000 mm diameter, steel treated process water pipe at Sappi’s Tugela Mill.

The tender was awarded to JG Afrika, who appointed Leomat Construction as the main contractor.

An innovative solution

The existing 1 000 mm diameter pipeline runs underground from the mill, through the town of Mandini and alongside the Mandeni stream before discharging into the river. The mill has the capacity to store its treated process water for nine hours, creating a buffer in which tie-in work could be done.

The new replacement project needed to minimise public inconvenience, while presenting an innovative, cost-effective, quality, efficient solution that also reduces environmental risk.

Sappi requested the use of HDPE for the new pipeline because the material is

more resilient to corrosion and chemical attack than the existing carbon steel pipe. The biggest advantage of HDPE is its flexibility and toughness, which led to JG Afrika’s design proposal of a twophased solution.

Phase one – an emergency intervention – involved laying the HDPE pipeline above ground from the mill to the discharge point. This pipeline would be within the 8 m allowed servitude. This solution provided a quick way to mitigate environmental and reputational risk.

The HDPE sections were butt-welded to allow for quick laying and early commissioning of this emergency intervention. The above-ground pipeline was active and running safely within six months of the tender award.

Phase two provided a long-term solution. While the above-ground pipeline was operational, a new trench was excavated along the alignment of the existing steel pipeline. The old steel pipe was removed from site by Leomat and sent for recycling/disposal. The above-ground pipeline was lifted into the existing trench during three- to fourhour shutdowns at the mill. The pipe was replaced in its final position for the road crossings.

Appropriate bedding was installed at the base of the trench before the replacement HDPE pipe was placed in sections and the trench backfilled. As the alignment remained unchanged, it could be safely M A R/ A P R 2020

39

INDUSTRIAL WATER

assumed that there would be no hard rock in the trench.

This two-phased solution allowed for the faster commencement of works, mitigating the risks of excavation near the operational steel pipeline, while remaining within the 8 m servitude.

Overcoming challenges

The project involved four road crossings and the Mandeni stream crossing. The road crossings were completed during the emergency phase, in their final long-term position.

At the crossing point at Old Main Road, the team found boulders in the existing pipe, preventing them from sleeving through the pipe with the new HDPE line. In one of the project’s biggest challenges, the team removed the existing steel pipeline and fed the new HDPE pipeline through the existing concrete sleeve. The pipe was then welded to the above-ground pipeline on either side of the road in a single nine-hour shutdown.

When crossing the Mandeni stream, the design methodology included the temporary pipeline being strapped to the existing weir to allow for the weir to be broken open and the existing pipe removed. This daring and difficult

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solution was considered a design and construction feat.

Unusual pipe size

With a treated process water outflow of 50 Mℓ/day, the new pipe needed to be 800 mm in diameter.

Pipelines of this diameter are not common in the water engineering field, and are generally only found in bulk water and sewerage operations.

This project not only made use of an uncommonly large-diameter pipeline but adopted a unique methodology that used the best properties of the material of choice, HDPE, in an innovative and risk-averse way.

HDPE is incredibly workable, flexible and tough, which enabled the team to double-handle the pipes in the two-phased approach. The design and construct approach also ensured that the contractor’s wealth of knowledge and expertise of construction techniques and efficiencies would be introduced during the design phases of the project by the engineer.

The innovative approach adopted in this project resulted in it receiving a Highly Commended Award for Technical Excellence at the 2019 PPSSAICE Awards.

www.wisa2020.org.za

31 May - 4 June 2020 | JHB | South Africa

ndeck

CONFERENCE

so

2020

llhand a #

Reduce water demand and increase supply

Manage resources for a capable ecology

Manage and monitor effective water and sanitation services and infrastructure

Govern and

Improve raw water quality and management

Develop skills and technology innovations and distuptors

regulate the sector

CharnĂŠ Millett-Clay Sponsorship & Exhibition Manager Tel: 011 463 5085 Email: charne@soafrica.com

Carolyn Melnick Project Manager Tel: 021 422 2402 Email: caro@soafrica.com

+27 (0)11 867 5001

52B Le MaĂŽtre Street, Brackenhurst, Alberton

www.prei.co.za

sales@prei.co.za

INSTRUMENTATION & CONTROL

The world’s toughest liquid analysis systems Prei Instrumentation’s customers choose Turtle Tough sensors because they conduct liquid analytics in the toughest conditions in the world.

They operate in mining, precious metal and ore refinement, and extreme chemical processes, where most sensors are unable to provide accuracy or longevity.

D

eterioration in the accuracy of sensors creates costly wastage, as process control is affected. Additionally, in these extreme environments, many sensors require intensive maintenance and frequent calibration, which are timeconsuming and costly processes.

Prei Instrumentation’s customers choose Turtle Tough because we deliver on our promises: providing substantial cost savings through better sensor performance.

Not only do we save them money, but we simplify the human factors required to keep the process measurement systems running effectively.

Improved measurement accuracy and process control

Turtle Tough sensors are designed to provide accurate measurement for significantly longer than any other sensor.

Custom-made to provide lower rates of expiration, slower accuracy degradation and reduced fouling, our sensors are reported to provide massive savings to our customers through better accuracy and tighter process control.

Maintenance-free

All Turtle Tough pH, ORP, conductivity and ion-specific measurement sensors have no serviceable components. This means completely maintenance-free operation – for the entire life of the sensor. A truly superior sensor must be impervious to ingress.

Turtle Tough sensors are solid-state and totally sealed for life. Not only will they resist process contamination but they are completely maintenance-free. There is no gel or electrolyte to be refilled, no reference to replace, and no o-rings or seals to be compromised or replenished.

Longest life in the industry

Turtle Tough sensors boast significantly extended replacement intervals, reducing the time and manpower required to replace and install sensors.

Rather than a one-size-fits-all approach, each sensor is optimised for its intended process use, with various salt mixtures and polymer formulations. Our proprietary pH glass and ORP elements provide unmatched performance in harsh environments.

By utilising solid-state conductive reference junction polymers, we are able to achieve accurate measurement while resisting process contamination into the reference system.

This ability to maintain high ionic conductivity while resisting aggressive gas intrusion is what makes our sensors outlast virtually all competitors in difficult process control conditions.

Intelligently designed for extreme applications

Turtle Tough’s patented and advanced technology will revolutionise the way you experience liquid analysis. Our entire range of pH, ORP, conductivity, dissolved oxygen and ion-specific sensors are designed to be physically and chemically superior, providing long life and high performance in the world’s toughest environments.

Through decades of experience supplying sensors into the world’s toughest applications, we have developed sensors that are optimised for high hydrofluoric acid, saturated sodium, high sulfide, organic solvents, high cyanidation, ultrapure water, high temperature and slurry/ viscous applications.

Turtle Tough analysers

The TT-MA Analysers have been designed specifically to interface with our extreme Turtle Tough sensors to provide the maximum possible service life to the sensor. The unique modular design enables you to create a full multiparameter analyser with any combination of different analytical modules including pH, ORP, dissolved oxygen, conductivity and ion-specific.

Functional modules can also be added, including digital Modbus, datalogging and relays. The TT-MA analyser family consists of the most economical full-feature industrial analysers available in the marketplace, often at a fraction of the cost of other analysers.

Turtle Tough sensors and analysers are sold and serviced by Prei Instrumentation, which has more than 30 years’ experience in your liquid analysis applications, especially in tough applications.

Neville Jegels Tel: +27 (0)11 867 5001 Cell: +27 (0)71 202 0703 prei.co.za M A R/ A P R 2020

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INSTRUMENTATION & CONTROL

SURGE ANALYSIS IN A NUTSHELL

In recent years, the demand for performing surge analysis during the design process of water transmission lines has increased. Such analysis produces very accurate results of the surge elimination process and enables the designers to select the best surge protection components.

T

here are several important differences to note between pipe network analysis and surge analysis computer programs.

In the global market, pipe network analysis programs are well known among water engineers and system designers.

This type of software simulates a steadystate condition, fire protection scenarios, continuous and gradual system variability over time, the filling and draining of reservoirs, and other such scenarios.

On the other hand, surge analysis software deals only with scenarios where changing flow characteristics may produce transition flows – i.e. very rapid change of the flow conditions, in a fraction of a second (see Table 1).

Among others, the following scenarios are usually analysed: sudden shutdown of pump/s due to power outage, starting and stopping of pump/s operation, and valves opening or closing along the supply line and to consumers.

the locations and sizes of the required air valves – the goal is for efficient air control in the system.

The first stage of the surge analysis is a steady-state analysis of the system in order to make sure that the data and hydraulic conditions of the model are consistent with the field conditions.

Stages of the surge analysis The second stage is running a simulation Prior to performing the surge analysis, it is of the system without any protection important to run software for determining means – i.e. with no surge protection components and devices. The PIPE software identifies the flow changes NETWORK SURGE ANALYSIS of the system and presents the ANALYSIS pressure envelope along the • Steady state or gradually • Sudden change of pipeline. This simulation of water Flow changing flow/transition flow surge is based on the worst-case state scenario, such as an abrupt power • Slightly compressible outage in the pump-reservoir system • Nonwhere all pumps are stopped at the Two phases (water compressible • same time.

Liquid and air) (Newtonian) In the next step, surge protection Two states of matter • Single phase • solutions are designed and checked (vapour and liquid) for determining the optimal cost• Full and partial crosseffective solution from the whole • Full crossPipe section flow – relief basket of possible solutions – i.e. section flow and intake of air surge anticipating valves, pressure TABLE 1 Pipe network analysis software versus relief valves, pump control valves, surge analysis software non-return valves, surge tanks, and Note that the required database for the two types of air valves. programs is almost identical (such as the layout of the In the final stage, the validity of pipeline). Therefore, there are programs that include the the solution is checked and verified. two types of the analysis modules.

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MAR /APR 2020

Bermad solutions for surge protection in pumping stations

Running additional simulations will show how the recommended solution prevents or reduces possible damage caused by the surge.

Software applications for sizing and positioning of air valves

Several manufacturers in the market provide software for the sizing and positioning of air valves. These software applications are programmed to ensure efficient air control in the system, in order to achieve the following goals: • prevention of air pocket accumulation in high points along the pipeline in order to maintain full cross-section flow • efficient pipeline filling • prevention of vacuum conditions during pipeline drainage or burst • prevention of water column separation in critical points of the system.

Modelling surge protection solutions

A combined solution of a surge anticipating valve installed in the pumping station combined with air valves, positioned along the pipeline in key positions, is a leading cost-effective and common solution.

The surge anticipating valve relieves excessive energy from the system, reducing or eliminating pressure rise, while the air valves open immediately in pressure-drop

INSTRUMENTATION & CONTROL

GRAPH 1 Bermad-Air software for sizing and positioning of air valves in transmission pipelines

situations in order to prevent vacuum conditions in the pipeline.

Performing surge analysis with surge analysis software programs produces accurate results of the surge prevention process and the component selections.

This provides vital design and operation data. The location, size and type of the surge anticipating valve are the main parameters for determining the best solution.

The software enables an optimisation process by considering parameters such as relief flow rate and required reaction speed.

For example: on one hand, you require the fast opening of the valve before the return of the water column to the pumping station; on the other hand, the slow and controlled closing of the valve is essential in order to prevent secondary surge during the closing process.

In kinetic or combination air valves, a slam phenomenon of the float may occur during pipeline filling or transition flows.

When the air valve relieves air in high flow/velocity situations, the water reaches the float, which closes and may slam the kinetic orifice. As a consequence, a rapid change of the flow velocity may occur and lead to surge.

The solution is to add a surge prevention/ anti-slam (SP/AS) device for controlled and moderate air relief that prevents slamming of the float.

The software enables the designer to check the inlet and outlet air flow for each

air valve installed along the pipeline. As a result, the designer can reach sensible engineering decisions – i.e. whether an SP/AS device is required or not.

Furthermore, in order to reach the optimal solution, the software allows for attributes to be set for transition pressure and the effective orifice size of the surge disc.

Graph 2 depicts the pressure and air flow through three units of 6-inch combination air valves versus time, with and without an SP device: t=2 – pump shutdown, pressure drops to atmospheric pressure t=2-26 – vacuum condition, the air valves allow air intake to the pipeline preventing negative pressure t=26 – pressure turns to be positive Green line – without SP device t=26-30 – uncontrolled high flow of air relief t=30 – water reaches the float, the float slammed resulting in surge Black line – with SP device t=26-27 – high flow air relief t=27 – jumping of the surge disc (SP) t=27-70 – controlled air relief through the orifice, the surge is prevented

Summary - critical data for performing surge analysis

Pipeline profile – in order to produce results that professionally simulate the reality, it is necessary to perform the modelling based on an accurate pipeline

profile that includes all the critical points of slope change along the pipeline.

Analysing according to the beginning and the end altitudes of the pipeline only may cause significant deviation from the real-life results.

Type of non-return valve – non-return valves have a significant influence on the analysis results. The faster the closing, the smaller the surge. By enabling less reverse flow of the water column, the closing of the non-return valve cuts the water column before it succeeds to accelerate back to the pumping station.

For example: A clap-type non-return valve requires 90 degrees of closing travel, therefore, such non-return valves close much more slowly compared to a springloaded non-return valve (nozzle), which has very short closing travel.

Inertia – shutting down a pump with greater inertia causes slower declining of the water head. Therefore, the higher the inertia, the smaller the surge.

A strong partner

Bermad’s application engineers have many years of experience in performing surge analysis of water transmission pipelines.

Together with local agent Macsteel Fluid Control, Bermad can provide surge analysis services to consulting engineers and system designers.

AS device in air valve model C70-AS GRAPH 2 Three units of 6-inch C70 air valves – air flow and pressure at the air valve node (KYPipe program)

Yuxi project, China – three units of 12-inch surge anticipating valve (PN40) 835 in the pumping station and 6-inch C70-SP air valves along the pipeline M A R/ A P R 2020

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INSTRUMENTATION & CONTROL

An IoT project with a surprising outcome The Kololo Game Reserve is located near Vaalwater, Limpopo. Because of its location in a rural area, the reserve requires its own water source.

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MAR /APR 2020

INSTRUMENTATION & CONTROL

Keller LoRa scheme

K

ololo’s water system consists of three stages: a water well, eight accumulating tanks, and a distribution system of pipes and hoses. The water from the 100 m well is pumped over 1 km into the eight 5 000 ℓ tanks located on a hill. From here, the water is distributed downhill, via gravity, to the lodges.

Measuring levels

Measuring the water levels in both the well and the tanks is important to determine water availability. To assist in this regard, Keller installed a complete level measurement system in one of the tanks in February 2020. As all eight tanks are connected, the level measured is representative of the level in all the tanks.

Due to Kololo’s size, a wireless IoT (internet of things) solution was needed.

However, the reserve’s rural location meant minimal cellular coverage. The chosen solution therefore communicates wirelessly via a LoRa (long range) network.

A typical local LoRa network consists of three basic elements: 1. A digital sensor or gauge 2. A LoRa transmitter 3. A LoRa gateway – the receiver, which is connected to the internet by Ethernet or Wi-Fi. In the case of Kololo, the LoRa gateway is a Laird Sentrius gateway, and the LoRa transmitters are Keller’s own ADT1 LoRa modem. A Keller Series 36XW digital level sensor is connected to the modem, measuring pressure and temperature.

The ADT1 retrieves the data from the level sensor and transmits it, together with barometric pressure and air temperature, to the LoRa gateway. Finally, the LoRa gateway forwards all the data via the internet to Keller’s Kolibri Cloud where it is stored.

Data can be viewed in the Kolibri Cloud web app, with additional features including exporting and printing of data, converting data to other units or even tank content calculations, among others.

Installation

Installation and set-up took some time, as it required finding precisely the right transmitting power, without overpowering. Given the location, it would be difficult to return to change batteries, for example.

After installation and set-up, the system started measuring every hour.

A day later, the data showed a downward sloping chart. Inspection of the difference between two measurements during the night showed a difference of approximately 100 ℓ/ hour. A leak was the only possible cause.

An inspection found that one of the pipe threads was partly pulled out of junction in one of the tanks, causing leakage.

Thus, the system proved itself after just one day.

Consideration is now being given to extending the system with a Keller Series 26X digital level sensor for the borehole, in order to monitor basic water stock.

a change of the diesel level with just a level sensor might not always work if the level is compensated with water to the old level.

However, based on conductivity it is possible to detect a change in the mixture. Water is heavier than diesel and has a different conductivity. The change in conductivity therefore represents the presence of water in the diesel tank. Kololo therefore opted to install a Keller Series 36XiW-CTD. This is a digital combined level and conductivity sensor.

Conclusion

A level measurement system provides actual data about fluid levels. By storing this data and building up a history, enormous statistical insight can be gained into the consumption and/or malfunctioning of the system.

Thus, it can lead to great savings or prevent unnecessary repairs and nonrevenue problems.

This system can be applied in all fluid level measurements across a variety of industries – game reserves, boreholes, agriculture, petrochemical and many more. Every Keller sensor with a digital output can be applied in IoT applications.

Kololo stores its water in eight tanks

Kololo’s electricity system

Although Kololo is connected to an electricity network, it has a diesel generator for backup power.

The diesel tanks run the risk of water ingress during refilling. There is also the risk of diesel being stolen, and often-times thieves will fill the tanks with water to

Testing LoRa reception at the measurement spot

compensate. For a diesel generator, this can be a catastrophe as water in an engine will cause major damage with high repair costs.

As a LoRa system cannot measure faster than once every 15 minutes, detecting M A R/ A P R 2020

47

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Make water security the top priority

WATER STORAGE

The lack of a consistent and reliable water supply is having a big impact on the growth and profitability of many businesses in South Africa – particularly those in the manufacturing sector.

common in new developments, both warehousing and residential, for insurers to require property owners to install sprinkler systems and standby water tanks.

As South Africa increasingly hears about the possibility of ‘water-shedding’, it is imperative that responsible businesses build in contingencies, such as the installation of water tanks, in order to mitigate the risks of low water pressure, watershedding, or even no water being provided through the municipal water system.

W

ith roughly 663 million people without adequate access to drinking water and 2.4 billion people still lacking access to sanitation, water security is still considered to be one of the biggest global risks.

Businesses therefore need to act swiftly to implement measures and solutions that are going to mitigate water security risks and better prepare them for an uncertain future.

Mitigating risk

According to Heiner Freese, COO and CFO at SBS Tanks, water security has become an ever-increasing business objective in South Africa. He says businesses should be – and some already are – looking at creating their own water supply, rather than relying on the traditional water authorities to supply water.

Additionally, the cost of water has increased drastically and will continue to do so. This makes alternatives, such as collecting rainwater and harvesting water from unused resources, economically viable, while providing continued supply that may otherwise not be guaranteed.

Storage solutions

Nearly all industries require water, even if just for drinking and hygiene purposes. Liquid storage tanks are a safe way to store both potable and process water.

According to Freese, it is within non-food manufacturing environments that mitigating water security issues is crucial and becomes a safety concern. A furnace, for instance, that does not have sufficient water for cooling could explode, threatening life and property. It is also becoming more M AR/ APR 2020

49

GROUNDWATER

GROUNDWATER FLOODING: two countries, similar challenges When urban development is undertaken without considering existing groundwater conditions, the result can be regular flooding that damages buildings and infrastructure.

W

hen groundwater conditions cause regular flooding, practical engineering design is a vital part of the solution, says Ismail Mahomed, partner and principal hydrogeologist, SRK Consulting.

Recent SRK projects abroad and locally have demonstrated similar challenges related to groundwater flooding. In arid regions like the Middle East, urban and industrial development has significantly changed the geophysical and hydrogeological environment. In one project, this was exacerbated by the reclamation of land along the coast.

“In this case, a number of factors led to increasing recharge levels to the shallow groundwater system,” says Mahomed. “These included water losses from leaking potable water distribution networks and from sewerage systems – as well as excess water from irrigation systems. Under natural conditions, the groundwater would have discharged into the sea or into a wadi – a valley, ravine or channel that is dry outside of the rainy season.”

Given the dry conditions in this region, stormwater management is generally a low priority; so, when it does rain, run-off from roads and hardstanding areas frequently ponds in local depressions or man-made paddocks, as the ground surface is flat and disturbed. This ponded water then seeps into the ground, contributing to groundwater flooding.

“Our project focused on a recently developed industrial and township complex in the Middle East, where the water was rising above ground level. This flooding impacted on civil infrastructure, public health, the environment and road safety – and could potentially even threaten further development of the area,” explains Mahomed.

Engineered solution

Given the legal restriction to the discharge of effluent, and the fact that some losses are inevitable from water and wastewater infrastructure, an engineered solution to the problem was required. A groundwater collection system was engineered, consisting of a network

Ismail Mahomed, partner and principal hydrogeologist, SRK Consulting of subsurface drains that decanted into collection sumps and were pumped out.

“The gravity drains make sense conceptually, but in a flat topography – where there is less than 5 m rise in the landscape up to 6 km from the coast – it was difficult to achieve the necessary slopes to allow flow under gravity,” Mahomed says.

He highlights that there were some important factors to consider when determining the rate of inflow into drains. These included estimating the rate of artificial recharge into the surface from various sources.

“This estimation can be done in great detail. However, the complexity in estimates may result in overly complicating the recharge distribution, with little gain in the drain inflow accuracy.”

Shallow groundwater and leaking municipal water seep into a basement excavation on a Johannesburg construction site

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MAR /APR 2020

GROUNDWATER

The recharge distribution and accuracy should inform the numerical model grid size, while the depth of the drain – in a particularly high hydraulic conductivity setting – will have a marked impact on inflow rates into drains and ultimately on design specifications.

“Where aquifer morphology dictates, it is important to ensure the drains are not set within deeper productive aquifers.

This would draw additional water into the drains from the deeper aquifers, but without achieving a lower water table as desired,” he says.

Local successes

A project with a similar challenge was conducted in Johannesburg. Here, an excavation was under way to create a basement for a sports complex, when a combination of municipal water and shallow groundwater seeped into the excavation.

“It is not uncommon in this area for shallow – sometimes perched – water tables to cause localised flooding of construction activities, especially during particularly wet seasons. This is often exacerbated by leaking water and sewerage infrastructure and from excess garden watering,” says Mahomed.

He adds that, in many cases, it is difficult to identify the source of the water, although environmental isotopes can provide a cost-effective tool for determining if the source is municipal mains, groundwater or both.

The flooding of the excavation could be dealt with using a cut-off trench, which was incorporated into the construction process; fortunately, it was still early in the construction stage of the facility.

“The slope and infrastructure were favourable, and the flow in the cut-off trench was under gravity – discharging into municipal stormwater drains.”

He notes that – in a residential setting – space restrictions and installed infrastructure could often limit the type of solution that could be applied.

“In these cases, gravity-based systems are ideal, as a pumped solution adds maintenance and running costs.

Infrastructure would also be placed at risk in the case of a pump failure. No one wants a flooded home basement because the pump system had failed or there was a prolonged power cut.”

Near-surface seepage

In another incident, to the west of Johannesburg, seepage from shallow groundwater and interflow has affected municipal and other infrastructure. Close to the toe of the Witwatersrand Ridge’s steep slopes, business premises have been built on a prepared platform.

“These platforms are often cut into the slope, exposing the near-surface seepage zone. A study was initiated by the authorities into the seepage, because of its extensive damage to infrastructure. Also, residential homes near these discharge zones have rising damp issues and persistent flows into streets,” says Mahomed.

Under natural conditions, the streams in the valley bottom would have been the recipients of this groundwater flow.

He highlights that the use of vegetation, which can address some of the shallow-occurring water, was potentially a missed

opportunity in both the local and the Middle East situations. In one case, the shrubs and trees in the area had actually been removed.

“These projects highlight that urban artificial recharge, combined with changes in the geophysical environment brought about by construction and land development, can result in significant risk and damage to critical municipal infrastructure. The engineered solutions may need to be conservative, but must deal decisively with persistent flow, as these seemingly small seepage zones pose significant long-term risks,” Mahomed explains.

He notes that while individual property owners may try to solve the issue locally through French drains and diversion drains, a broader approach is required to safeguard municipal infrastructure and prevent large-scale damage.

“It should also be remembered that both South Africa and the Middle East are water-scarce areas. Minimising the loss of mains water should therefore be a priority that helps drive sustainable solutions to groundwater flooding,” he ends.

TECHNOLOGY

Accelerating SA’s water fightback Dr Jo Burgess, senior technology consultant, Isle

Innovation holds the answers to many of South Africa’s water and sanitation challenges, but the average time for a new technology to become mainstream is 15 to 20 years. Dr Jo Burgess discusses how historic barriers to water innovation can be removed to pave the way for much needed progress.

South Africa faces a monumental task in securing future water supplies and it is clear new approaches are needed. What role can Isle play?

JB Isle is a global technology and innovation consultancy that works closely with the water and industrial sectors in South Africa to introduce new water technologies. Key to this are two Technology Assessment Groups (TAGs) – collaborative innovation forums for technology users. We have several TAGs worldwide, each operating on the same principles but tailored carefully to its location.

It is impossible for the water sector and industrial users to assess all technologies and differentiate the good tech from the repackaged old tech and the low-quality tech. TAGs take that workload away.

In South Africa, we have a TAG for the water sector itself and an industrial TAG for other sectors such as power, food and beverage, pulp and paper, mining, and pharmaceuticals.

Water and energy have been hot topics in the public mind since Cape Town’s close call with Day Zero and load-shedding. For industry, a continuous supply of energy and good quality water is no longer guaranteed and that means sectors like manufacturing need to take control of their resources if they are to continue to be viable.

For the water industry, it means the sector must be able to increase its abilities to

deliver its product – and for that it needs new technologies. These high-profile water-scarcity issues have prompted a huge amount of activity and there are hundreds of people offering solutions.

What is the process of taking technology from research to trial and implementation?

It can take 15 to 20 years for a water technology to go from concept to mainstream. To be successful requires proof of concept for the experimental stages to be done extremely thoroughly, which can take four to ten years and cost millions.

Isle’s global team of around 60 scientists and engineers scout for emerging technologies from research centres, universities, backyard inventors – anywhere. The technologies are put through our internal due diligence process. We look at previous pilot or trial data, under non-disclosure agreement if necessary, and then put the technologies that pass the assessment into Isle’s online innovation portal.

The SA TAG and iTAG convene twice a year. Before each meeting, we match the innovation needs of members to the new, appropriate technologies we’ve assessed.

We then start interviewing the technology companies about their readiness to do business in South Africa. At the meetings, they give technical presentations followed by a Q&A and collaborative audience review, which is usually lively.

A technology presentation under way at a TAG meeting

How can this process be accelerated?

We can move faster by closing the communication gaps between technology developers and users and investors.

We have our portal and the TAGs act as launchpads into different markets.

Even with this acceleration, it is still a 10-year process.

In South Africa specifically, we have a memorandum of understanding with the Water Research Commission to work together in accelerating the market entry of the technologies that pass through their platforms. This facilitates a pathway for technologies to move into Isle’s global TAG network, which is a route to commercialisation around the world.

What are other common barriers to water innovation in South Africa?

There is a critical skills shortage in the water sector and, with so much technology out there, it is difficult for staff to keep up.

This works against start-ups that genuinely have a great technology. The amount of noise in the system is a problem. It dilutes the funds and incubator capacity that genuine innovators desperately need.

Other common challenges include: • Risk aversion – there can be concern among stakeholders about reputation. If they do something known to work 1 000 times before and it fails, there is no blame.

If they do something unfamiliar and it fails, they get blamed for bad choices.

We advise setting the expectation early

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PipeMinder-T provides real-time leak detection for critical water pipelines and is now deployed across the UK and USA

GROUNDWATER

that there is no need to ‘pick a winner’. This is about proving the business case effectively, which should be technology agnostic.

• Trial objectives not being met – a business case is often not tested prior to trialling, only the technical case. It might be a Rolls-Royce of a technology, but it might also be a R500 000 solution to a R500 problem.

It is important to develop a business case prior to decision-making.

• Rejection by operators – operators are typically only involved during the execution stage. Instead, engage them as part of the decision-making process so any concerns they may have are addressed early.

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What water challenges need tackling most urgently in South Africa? How can technology help?

The effects of climate change and lack of electricity supply capacity are the two factors that limit socioeconomic progress and cause environmental harm in various ways. Wastewater treatment works operating without electricity inevitably divert untreated waste into receiving water bodies, causing pollution.

Failing to use national manufacturing capacity means, indirectly, jobs are lost.

We also have urgent issues with emerging pollutants, dwindling freshwater resources, and increased drought and floods. These are new issues we need to face with new methods and inventions. We are currently prioritising emerging, disruptive technologies to minimise energy and water demand, and maximise water quality and energy production.

There is uncertainty around food security too. Our cities and agricultural regions are located according to historical rainfall and water availability. As this changes, we need to adapt. In addition, households in some parts of the country are still unserved by potable supplies and have no access to sanitation services.

South Africa must fundamentally alter the way it uses water. There is a huge opportunity to leapfrog into the Fourth Industrial Revolution – a new chapter in human development – and redesign our failing systems into world-beating new ones. Hundreds of technologies are emerging and being adopted but not quickly enough.

Our ability to accelerate and de-risk the uptake of new technology will help South Africa fight back.

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Do you have case study examples?

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The additional collection of high-resolution pressure data identifies pressure transients that contribute to pipeline fatigue and can even be a cause of emergent leaks. The removal of large transients and frequent M AR/ APR 2020

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2020

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TECHNOLOGY

Project timeline

pressure oscillations calms down water networks and in turn reduces the number of asset failures.

Isle’s support began in the UK market in 2011 and the technology was first presented at the European TAG in 2013.

A presentation to the US TAG followed and the technology was then shown at Singapore International Water Week.

Successful trials have been undertaken with two UK water companies and PipeMinder-T is now deployed across the UK and USA. James Dunning, chief executive at Syrinix, says: “Syrinix has worked closely with Isle, quite literally across the globe, as a valued and trusted partner for gaining an understanding of and entry to new markets.”

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MAR /APR 2020

Filtralite from Saint Gobain Uganda’s National Water and Sewerage Corporation (NWSC) began a pilot with Saint Gobain’s Filtralite® filter media, with support from Isle. The trial took place in Masaka, Uganda, where the raw water has high levels of iron and organic matter, especially during the dry season. This is challenging because these components can be difficult to remove.

Filtralite is made of expanded clay and was used as an alternative to traditional filter media during the trial. Expanded clay is characterised by its exceptionally high porosity compared to sand and anthracite, giving a superior capacity for solids retention. No changes to the infrastructure and pumping system were required.

Overall, the performance of Filtralite

media was 50% higher than sand media for iron removal, ensuring that downstream process units met national water quality standards. Additionally, the lower initial head loss and head-loss build-up will make pumping more efficient and reduce backwash frequency, leading to water savings.

NWSC will now collect more data during the rainy season to ascertain the performance of the two media through seasonal changes.

Isle assisted the project by introducing Filtralite to NWSC through its Water Innovation Platform for Africa, a TAG-like innovation programme that operates throughout Africa and is funded by the IFC (a member of the World Bank Group) and Japan’s Ministry of Finance.

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12 - 14 May 2020 CTICC, Cape Town, South Africa

WISA • EVENTS

WISA is looking forward to welcoming three distinguished keynote speakers to the WISA 2020 Conference and Exhibition taking place later this year.

What to look forward to at WISA 2020

T

he WISA 2020 Conference and Exhibition promises to be bigger and better than ever before, as it calls for collective and urgent action in the water sector.

sector, entrepreneurship and empowerment platforms.

According to Dr Marlene van der Merwe-Botha, head of the WISA 2020 technical committee, this year’s conference will differ from previous ones in that it will strongly feature young leaders in the water sector. The South African Young Water Professionals chair will close the conference, reflecting on the event and writing up the recommendations and findings that will go into a pledge of action that will be submitted to government.

“This is the one conference you cannot afford to miss. This is where people meet, engage and find inspiration to be re-energised until the next WISA conference in 2022,” says Van der Merwe-Botha.

This year’s keynotes

Day 1 of the conference will open with Daniel Silke, a leading analyst on the South African, African and global political economy landscape. He will discuss possible futures and global business trends.

Professor Stefan Uhlenbrook will deliver Day 2’s keynote address.

Uhlenbrook is a well-known hydrologist and award-winning academic on river basin modelling and on global changes on water cycle dynamics in South Africa. He is also the director: Academic Affairs at the UnescoIHE Institute for Water Education.

On the last day, delegates will be addressed by Sivuyile Pezulu, who will discuss topics including young professionals in the water

Mobile app

WISA is also in the process of developing a mobile app to be used at the conference to facilitate engagement at the event.

The app will enable users to view the full conference programme and tailor their own • 15 March 2020 – provisional programme published agenda for the event.

• 15 March 2020 – launch of the mobile app It will also enable

users to access participant contact details and arrange meetings and networking sessions with attendees, speakers, exhibitors and sponsors.

Attendees will also be able to submit questions for presenters in-session and participate in in-session surveys and live polling. “It presents an opportunity to engage more and I encourage everybody to download the app,” says Inga Jacobs-Mata of the WISA 2020 organising committee.

The app will go live in March and full functionality will become available once a user is a registered participant for the conference.

Register now

WISA 2020 will take place from 31 May to 4 June 2020 at the Sandton Convention Centre in Johannesburg.

This year’s theme, #AllHandsOnDeck, calls for all players in the water sector to address the country’s water crisis and work together towards a sustainable water future.

IMPORTANT DATES

• 31 May 2020 – conference starts

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