Biogas Magazine Edition 05 v09

INDIAN BIOGAS ASSOCIATION www.biogas-india.com

P. 12: Bioenergy part in internaaonal climate goals!

P. 16: A prickly pear cactus provides biogas P. 27: Potennal of Biogas from MSW P. 22: IBA - BFI Partnership

at Visit IBA booth Energy Renewable from India Expo, 2018 18 - 20 Sep,

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CONTENTS Published by

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IBA News

Biogas Training Tour 2018 - P. 6 The Biogas map as a knowledge base for Biogas utilization - P. 9

Research and Development

Potential of Biogas generation from Municipal Solid Waste: A Case of Ahmedabad City - P. 27

National Corner R&D landscape of Biogas in India - P. 38

International Corner

Bioenergy and it’s role in international climate and energy goals - P. 12 A prickly pear cactus provides biogas - P. 16 Biogas Plant Case Study from Portugal - P. 32

Case Study

Biogas recovery from ETP saves several latent operational cost - P. 24

Designed by: Indian Biogas Association Printed by: The Color impressions, Gurgaon, India

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Biogas Magazine | Edition 05 | 05

Foreword

he increasing readership of Biogas magazine is motivating us to further emphasise on the market need of Bioenergy and the impact the energy technologies and services will have on the utility markets. Keeping up with our earlier trend, in this edition, we have an appropriate mix of articles spanning recent activities of the association, some exemplary practices in biogas plants in India and abroad, discussion on potential cost saving techniques, essence of a strong R&D roadmap for progressive growth, and so on. The present edition aims to give particular focus on some of the investigation areas that may allow to uncover the impact of Biogas on electricity/biomethane market thus potentially facilitating accommodation of substantial shares of biogas in the energy mix. For our latest edition, the authors contributed with a proper attention on embracing challenges, and customized solutions. The need to mention about the fertilizing value of outlet bio slurry is equally important.

In our constant endeavour to excel, we launched an informative brochure on Biogas. It contains the basics, which is imperative to Biogas and Bio-slurry.

Several analogies and examples were given in the content. An Indian perspective is put forward for the scenario understanding.

We are overwhelmed with the positive outcome of Biogas training programs in Chennai, Bangalore, and Mumbai, which took place in the month of April 2018 in collaboration with German Biogas Association. The details can further be explored at

www.biogas-india.com. Also, we are delighted that the partnership with Burhani Foundation - India on the concept of “Circular Economy” and “Zero Organic Waste to Landfill” campaign” have started showing the results. The Biogas map section of “Biogas App” is getting the substrate and plant data from all over the country. Once developed, it can be a decision support tool for politicians, urban/rural planners, investors apart from handling soft aspects (raise interest, vitalise the debate, get a common base for discussion).

The abridged version of “Assessment of the status quo of the implementation and potentials of Anaerobic Digestion in India” has already been released. The full version, available for members only, shall be launched in Renewable Energy India Expo – 2018, which shall take place from 18-20 Septemtber 2018. We are going to showcase ourselves there with a full-fledged stall along with one day conference. This year’s general assembly is also planned during this period We hope that you find this issue both motivating and informative. Your contributions to make a mark in Bioenergy sector will always be appreciated.

Happy digesting! Let’s fertilize the energy together.

Binod Daga Vice President Indian Biogas Association

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Biogas Magazine | Edition 05 | 06

Biogas Training Tour, 2018

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iogas Training Tour 2018 got kick start at Chennai on April 23rd, followed by commencement at Bangalore, and Mumbai on April 24th and 26th respectively. After successful coverage of cities, like Delhi, Pune, and Ahmedabad in its earlier version in 2017, this time the event moved to the Southern and Western parts of India. The opening of training tour at Chennai also saw the launch of the “Informative Brochure on Biogas�, a brochure entailing basic information on biogas in English and Hindi, by Dr. T. S. Chandra, Emeritus Professor at Dept. of Biotechnology, IIT-Madras.

This exclusive Biogas Training Tour was organized

by Indian Biogas Association (IBA) in co-operation with German Biogas Association (GBA) and was supported by Indian Institute of Technology, Madras, CMR University, Bangalore, Institute of Chemical Technology (ICT), Matunga, Mumbai, and Indo-German Chamber of Commerce (IGCC).

The training tour entailed learnings on basics of biogas featuring the diverse spectrum of

feedstock used, several production technologies, multiple usage of biogas, along with essence of the unspent digestate (bio-slurry), its usage and treatment techniques, Indian biogas scenario, and German experience and journey in biogas.

Aforementioned topics were reflected upon by a line-up of high-level speakers like Mr. Frank Hofmann (GBA), Ms. Marion Weisheu (GBA), Mr. Gaurav Kedia (IBA) and Mr. Abhijeet Mukherjee (IBA).

This training tour also emphasised on importance of planning, operation and maintenance and safety in biogas plants. The training provided succinct information about the overall scenario of the Indian biogas industry in form of present status and growth rate of biogas plants across different scale, critical challenges being faced by the industry and its mitigating measures, the present legal frame work encompassing role of different ministries, available subsidy schemes, permits and clearances needed for setting up a biogas plant, and few case studies on existing biogas plants in India.

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An important objective of this event was to emphasise upon experience of German Biogas Association of over 9000 successful plants in a decade in Germany. India definitely need to take a proper understanding out of the German road map in biogas and similar success stories can follow after customizing as per the local needs and conditions.

The Biogas Training Tour 2018, attracted aspiring entrepreneurs, corporates, environmental enthusiasts, research scholars, academics and NGOs, and was extremely helpful in augmenting their elementary information in biogas. In this training tour mainly, topic covered by our speakers was biogas in India, biogas technologies, existing plants and prospective scope.

In nutshell, the event was instrumental in effecting a shift in the Indian btiogas sector. The Training tour will see its next edition in the fore coming years, looking to build up on the success of the 2018 edition in terms of participation, concrete contributions and coverage of more cities across India.

Author Vishal Kanchan Indian Biogas Association

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Biogas Magazine | Edition 05 | 09

The Biogas map as a knowledge base for Biogas utilization

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ur existing Biogas app, available at Google play store has a significant functionality of quantification of the resource potential to analyse the use of organic substrates and existing Biogas plant for heat, electricity, Bio-CNG and Bio-fertilizer. A Biogas map is a GIS system providing the locally available substrate on daily basis including urban and rural areas, which can be accompanied by information of the output of electricity, CO2 savings and other information with the help of inbuilt calculator.

Indian Biogas Association, in cooperation with Burhani Foundation - India is planning to start the quantification analysis of Biogas maps, followed by qualitative analysis as soon as the sufficient data are gathered.

We have classified the Biogas map with the different level of development; with basic information: the primary and secondary data of substrate and existing biogas plant. Furthermore, substrate levels are also categorised e.g., fresh cattle dung, dried cattle dung, dung from grown up cattle etc. Such a Biogas map is supposed to be the base for the medium and advanced Biogas map, of which features shall all be based on the analysis of annual substrate availability throughout the country. The medium Biogas map shall provide the energy output of the suitable areas with heat map along with Bio-fertilizer. The most advanced Biogas map shall not only provide the quantitative data, but also provide information about what to do next when people want to install a biogas plant.

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Biogas Magazine | Edition 05 | 10

Biogas map functionalities shall also focus on two additional items, in future: • Finances of the probable biogas system: revenues and costs • Installations: which Biogas plant providers are available With this information, a founded decision can be made on the implementation of Biogas. For the users Biogas map can serve as an underlying information base for local energy decisions.

Government can make a proper policy based. Till date the volatility in biogas policy has brought lot of uncertainties but once the primary and secondary verified data are available, the benefit of tool can clearly be seen in practice.

Author Akshat Sarolia Indian Biogas Association

In action Summarizing, the role of Biogas maps as a decision support tool can be divided into three different aspects: 1) The difference in users (politicians, urban/rural planners, investors, real estate owners), 2) Scale (city, urban/rural district), and 3) Soft aspects (raise interest, vitalise the debate, get a common base for discussion).

By taking all these three aspects into account, a full deployment of Biogas throughout the nation can be accelerated.

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Biogas Magazine | Edition 05 | 11

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Biogas Magazine | Edition 05 | 12

Bioenergy and its role in international climate and energy goals!

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he Earth’s climate is changing. The effects of climate change are visible globally, and most of these changes are adversely impacting human life. Sea levels are rising, the global average surface temperature is increasing, polar ice caps are melting and extreme weather events such as hurricanes and droughts are occurring more frequently and with greater severity.

There is an overwhelming consensus within the scientific community that the leading cause of these changes to the climate is the anthropogenic (resulting from human activity) emission of Green House Gases (GHG’s). The primary GHG’s are carbon dioxide, methane, ozone, and water vapor. While the earth has natural cycles, which balance the emission of these gases by absorption in the oceans, forests, etc. anthropogenic GHG emissions are increasing at such a rate that these natural cycles can no longer balance emissions, resulting in a net accumulation of GHG’s in the atmosphere.

Recently, it was reported that the atmospheric concentration of GHG’s (reported in Carbon Dioxide equivalents) is the highest it’s been in human

history at 410 ppm. This increasing concentration of GHG’s is a major cause of increasing global temperatures, leading to an increase in global surface temperature of 1 oC. It is widely agreed that in order to avoid the most severe effects of climate change, it is crucial to limit this global temperature increase to 2 oC, and ideally this increase would be limited to 1.5 oC. Fingers are pointed at the energy sector, which, while crucial for global development, is heavily depending on fossil fuels, and consequently responsible for 40 % of anthropogenic GHG emissions. More than 80 % of our global energy supply is still satisfied by coal, oil and natural gas. The world is addicted to fossil fuels, and it is proving very difficult to move away from them.

To have any hope of staying below the 2 oC target, we need to change the way we produce and consume energy. This was the central theme of the 2016 Paris Agreement – an international treaty signed and ratified by almost every country in the world. Member countries formally recognize the need to reduce their GHG emissions, and thereby reduce their dependence on fossil fuels.

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Models of global emissions under different scenarios show that in order to meet the emission reduction targets of the Paris Agreement, renewable energy technologies and energy efficiency will be crucial to future energy systems. Renewable energy sources including solar, wind, geothermal, hydro, and bioenergy, are some of the most cost effective, socially acceptable and low-emission sources for satisfying the human craving for heat, electricity and fuels for transportation. One of the most versatile and complex energy sources is Bioenergy.

Bioenergy is energy derived from biomass, which encompasses carbon-rich sources ranging from wood to agricultural crops to municipal waste.

Currently, bioenergy is the most widely used renewable energy source globally. Recent data shows that biomass provides 10% of the total energy supply globally and among renewables, it contributes about two thirds. We use bioenergy for everything.

Wood is used by populations in developing countries for cooking and heating. Wood residues like sawdust and wood chips are used by large combined heat and power plants to produce millions of watts of electricity to power homes and provide heat and hot water to keep the population warm and safe. Biogas produced from human and animal waste provides much needed energy to rural communities. Liquid biofuels like bioethanol and biodiesel produced mainly from agriculture

crops fuel our immense transportation fleet and are an important step in reducing our dependence on oil.

Bioenergy has the potential to play a major role in future energy systems.

Recent estimates suggest that we can sustainably double or even triple the amount of biomass we use for energy.

However, the way we procure biomass in the near future might change. Currently, the forestry sector is the largest source of biomass for the bioenergy sector covering 87 % of the contribution. This is followed by the agriculture sector at 10 % and finally, municipal solid waste from cities contributing 3 %.

In the future, there are certain trends we are likely to observe: The agriculture sector will take the lead in contributing a major share to the global bioenergy system. This will be mainly due to an increasing use of agricultural crops and residues for generating heat and electricity. Currently, millions of tonnes of agricultural residues are ineffectively managed, leading to serious environmental problems from fire and decay.

Transportation is the biggest missing piece of the global energy puzzle. We have done quite well in reducing the use of fossil fuels in the electricity sector, and to a certain extent in the heating sector, but the transportation sector, with its immense dependence on oil remains a major challenge. Electrification is the best solution, but we have a long way to go before the com

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Biogas Magazine | Edition 05 | 14

and dependent only on their emission reduction potentials, should be promoted.

Author Bharadwaj Kummamuru World Bioenergy Association, Stockholm, Sweden

plete electrification of our road and rail transport is feasible. Moreover, electrification does not currently seem to be a viable solution for aviation and maritime transport.

Biofuels fit the bill perfectly as a sustainable alternative to oil. Already, liquid ethanol and biodiesel along with biogas and biomethane are making major headway in replacing traditional oil-based fuels. In order to substantially reduce transport sector emissions, however, we need more biofuels, and all types of technologies irrespective of feedstock

Combined heat and power for the production of electricity, heat and hot water for both commercial and residential applications is another promising sector. There are many countries that have fossil fuel-based district heating (DH) systems, which can be economically replaced with biomass – e.g. wood chips and wood pellets. At the same time, countries with no DH grids can replace the use of fossil fuels in the industrial sector (e.g. iron and steel) with biofuels. Such technologies already exist and are highly efficient.

Although the range of benefits of bioenergy are quite apparent, there remain significant challenges.

Favourable policies are still not in place; fossil fuels still receive large subsidies, which creates an unfair market for bioenergy to compete with. Moreover, most of the policies to date have focussed only on electrification, which has made good progress, but means that the heating and transport sectors are lagging behind. Bioenergy has the greatest potential in the heating and transport sector, and hence favourable policies such as carbon taxes, blending mandates and investment support are crucial.

Returning to the question of climate change and the role of bioenergy – long term climate targets in international agreements (e.g. Paris Agreement) will fail without the significant expansion of bioenergy production and consumption. A majority of the cost-effective options for increasing the use of renewables in the near future rely on bioenergy.

As discussed, bioenergy has numerous benefits, and these must be taken into consideration when international delegates meet at the next climate meeting, COP24, in Katowice, Poland.

Several years ago, almost every country in the world agreed to the Paris Agreement on Climate Change. It was a huge success. Now, all eyes will be on Poland in December 2018. The negotiations leading up to COP24 are crucial for the future success of the Paris Agreement. A major challenge is developing a guidebook or operating manual for the Paris Agreement.

To achieve this, the negotiations will follow what is called the Talanoa Dialogue. The dialogue is built on the tradition of the Fiji Islands, the country currently holding the Presidency of COP, and it means a tradition of “inclusive, transparent and participatory” dialogue. This dialogue is essential to meeting the Paris Agreement’s long-term goals, and it comprises

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of three central questions: Where are we? Where do we want to go? And How do we get there?

Couple of years back, when the Paris Agreement was signed and adopted by more than 195 countries, there was incredible political momentum. Now, the tough part begins. A package deal – Paris Agreement Work Programme (PAWP) – has to be adopted in Poland at COP24 to be held during December 3 – 14, 2018. However, there are still many differences including financing, transparency, differentiation, mitigation and adaptation etc. which have to be resolved before any consensus can be arrived at.

Negotiators will meet again in Bangkok in September to continue working on a draft negotiating text which is crucial so as to have any sort of agreement in Katowice in December.

We are short of time. Recent research work shows that we are going in the wrong direction in terms of emissions and we have a very limited carbon budget to meet the Paris Agreement goals. We have to be speed up the transition. Bioenergy is already an important part of the energy mix and will be an integral part of any future scenarios.

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RENEWABLE ENERGY INDIA EXPO

MUNICIPALIKA

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Biogas Magazine | Edition 05 | 16

A prickly pear cactus provides biogas

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exico has a great deal of potential for biogas. By 2024, the country wants to achieve an energy mix with 35 percent renewables. Currently, the proportion is a good 18 percent, consisting mostly of water and wind power. At 0.3 percent, energy from biomass hardly plays any role at all. But within this period, this amount is still supposed to increase to 3 percent. There is no feed-in compensation for electricity from renewable energies, however.

Barren mountains, dried up bushes, scrub brush and yellow grass at the foot of bizarre cliff formations. You can’t get more Mexican than that. Then is it any surprise that Juan Manuel Castañeda Muñoz and the other members of his cooperative are operating their biogas plant with cacti? “Cacti grow very quickly”. The farmer points to the planted fields of the cooperative near Cavillo in the state of Aguascalientes.

The knee-high Nopal – a prickly pear cactus – stand there row on row like an army. Between the rows are wooden crates waiting to be filled. About fifty workers earn their pay here doing harvest and maintenance tasks. “Since

we’ve been operating the biogas plant, we have employed twelve more people”, explains Castañeda. That’s important in a region from which many people emigrate to the USA looking for work – as long as they still can.

Juan Manuel Castañeda Muñoz is a member of the Comite Estatal Sistema Producto Nopal. This cooperative of 50 farmers cultivate Nopal on a total of 560 hectares. 70 hectares of prickly pear cacti are grown for the biogas plant. In principle.

The tasty and healthy cactus is also valued as a vegetable in Mexico. But the prices fluctuate a great deal. “Between November and February, the prices are very high; then the plant runs at just one third of its total capacity because we prefer to sell the cacti”.

Cacti can be used for 20 years During this season, other regions of Mexico do not produce as much cactus. Here, however, in the middle of northern Mexico, this undemanding plant grows well the whole year long. So it makes more sense to ferment the farm’s cacti during the months when there’s a large supply across the country. One cactus plant can be har-

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Biogas Magazine | Edition 05 | 17

vested for up to twenty years. For use as a food, the leaves grow for about 30 days or, to use the plant for energy, for up to four months. “But no longer than that; otherwise, the methane yield decreases”. Castañeda breaks a light-green leaf off of a plant. Contrary to expectations, the spines are soft; later, they even fall right out.

The methane yield of the prickly pear cactus is 860 cubic metres per tonne of dry matter, which is equivalent to 10 tonnes fresh weight. This means that with respect to its weight, this prickly fellow does not have an especially high yield.

But in terms of the yield per hectare it does. “In three harvests we get a total of 600 tonnes of fresh weight per year and hectare”. Moreover, cactus is only in the biogas plant for 16 hours, a very short period.

A look at the plant near the farm, though, makes it clear: a great deal of mass has to be moved in order for it to operate. The cactus leaves are chopped and are placed in the digester. No water is added. Just 1 percent cow dung is added to the mixture. Nopal is fermented in four large containers of 1,000 cubic metres each. The containers are four metres tall and are made simply of foil, iron lattice and some concrete, stones and soil. “All of the components can be bought locally and the work was done by a Mexican company”, explains Miguel Angel Perales de la Cruz, who planned the design, financing and construction of the plant for the cooperative.

These hybrid constructions of a lagoon digester and a reactor are not heated, however.

Miguel Angel Perales de la Cruz, who planned the design, financing and construction of the plant for the cooperative

“When we’re at peak production, everything here is covered in cactus leaves”, continues Perales. The plant grounds cover an area as large as two to three football fields. And the light-coloured concrete gleams, demonstrating the involvement of project partner Cruz Azul.

The large Mexican concrete manufacturer utilizes the electricity, more than seven million kilowatt hours, produced by the Caterpillar generator, which has a capacity of one megawatt. Cruz Azul also provided far more than half of the investment costs of two million euros (converted from pesos).

The rest came from the Mexican National Council of Science and Technology (CONACYT). Room for expansion is planned, but it will probably not occur quickly. The plant, even at its current size, does not yet run at full capacity is also because the state-operated provider and network operator Comisión Federal de Electricidad (CFE) allows feed-in only at certain times so that the grid is not overloaded.

Long approval phases Indeed, the Mexican government has ended the CFE monopoly by enacting an energy reform.

However, the commission is still tenacious as ever with regard to some issues. For example, two years passed between the approval for production of electricity and the approval for feedin for the Nopal biogas plant. The production costs for electricity generated by cacti are about four euro cents per kilowatt hour. Cruz Azul pays the cooperative more than twice that much.

Alex Eaton, a U.S. citizen, Established Sistema Biobolsa seven years ago

Violeta Bravo de Sepulveda is from Mexico.

She is working for a project of the Brandenburg University of technology(BTU) CottbusSenftenberg and the Center of research and Technological Development in Electrochemistry (CIDETEQ) in Queretaro, Mexico.

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Biogas Magazine | Edition 05 | 18

has in interest in the plants’ long-term production of methane. Of course, the operators profit from this as well. “The farm recoups the investment quickly”, explains Alex Eaton. And in this way, they can also pay the loan back. Rancho Sinai would have to pay almost 290 euros per year and hectare just for industrial fertilizer. This is a significant item because the farm grows the feed for its 250 cows on an area of 100 hectares. In addition, there are energy cost savings of nearly 3,000 euros per year.

The state supports so-called clean energies only through investment incentives, subsidy programmes and, starting in January 2018, with Clean Energy Certificates. However, these clean energies also include modern gas and nuclear power plants.

For this reason, the agreement with Cruz Azul is a good deal, at least during times when there is a great supply of Nopal. The plant, however, which has been providing electricity since September 2015, is supposed to make money primarily by producing solid and liquid fertilizer.

It will be made in a hall built especially for this purpose.

Laboratory experiments and field trials certify its effectiveness. What’s missing, however, is a sales market for the organic fertilizer. Now most of it is used on the cooperative’s own fields.

The plant concept of Sistema Biobolsa also focuses on fertilizer production and using its own power production.

“Eighty percent of the area of this dairy farm is fertilized with the residue from their biogas plant”. Alex Eaton points to the seven lagoons with their sun-bleached foil covers, inflated by the pressure of the methane gas. To regulate the pressure, old automobile tires are situated on the foil. The plant, 280 cubic metres in size, is located at Rancho Sinai near Zumpago de Ocampo, northeast of Mexico City. Eaton, a U.S. citizen, established Sistema Biobolsa seven years ago. He walks out onto one of the foil covers and starts to rock back and forth. If the lagoon gurgles, it means that only liquid is fermenting there thanks to a separator that separates the solids out.

Maintenance is lacking for small plants Eaton’s team constructed this plant with a motor available on the local market. This way, the total costs of the plant were just about 15,000 euros (converted from pesos). Sistema Biobolsa covered two-thirds of the costs with an interest-free loan. The Ministry of Agriculture contributed the other third. There are budgets for these sorts of investment support. However, experts complain that these monies are not always used in a meaningful way; too often a scattergun approach is applied. Many small biogas plants are not functioning because the manufacturers do not provide ongoing maintenance, among other problems.

But not Sistema Biobolsa. As a lender, the company

The farm uses biogas not only to heat the hot water for cleaning the milking equipment, but also to run the motor for the milking machine. Sistema Biobolsa modified a Honda diesel motor so that it runs on methane. The motor uses a V-belt to operate the milking machine.

But the V-belt can also be transferred to a diesel motor if not enough biogas is generated in the lagoon or if the gas motor does not work for some other reason.

Alex Eaton established Sistema Biobolsa initially as a small NGO and then he converted it into a company with headquarters in Mexico City. Today, 45 people are employed at Sistema Biobolsa. There are small subsidiaries in Central American and soon in Kenya and India. Sistema Biobolsa has already installed more than 3,000 plants in Mexico. They range from 4 to 280 cubic metres in size. As modules, they can be combined. For the most part, they consist of small household plants used by families for cooking.

In Mexico, small farmers also have a particularly difficult time with low milk prices. Saving even just 30 euros for natural gas per month is a great help.

Furthermore, small farmers can pasteurize their milk inexpensively with biogas, making it easier to market it directly.

Sistema Biobolsa has built about 100 larger plants. The methane from these plants is used to heat piglet enclosures, in cheese factories and to run milk machines such as those at Rancho Sinai.

The early morning fog drifting over the fields dissipates slowly. You could almost believe you were in Schleswig-Holstein in northern Germany. This elevation of this area around Zumpango de Ocampo is just about 2,300 metres, which means low temperatures at night. For this reason, the plant’s methane yield fluctuates between 60 and 100 cubic metres per day, depending on the season and the

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weather. “Lagoons are inexpensive, but they are also like black boxes that are difficult to check”, says Violeta Bravo de Sepúlveda. “Many function poorly or not at all and are not able to harvest the existing methane potential from the substrates”, she continues.

A scientist, Violeta Bravo de Sepúlveda is from Mexico; she completed studies in Germany and is working for a project of the Brandenburg University of Technology (BTU) Cottbus-Senftenberg and the Center of Research and Technologic Development in Electrochemistry (CIDETEQ) in Querétaro, Mexico, an important industrial location in the state of the same name.

For example, together with poultry producer Pilgrims Pride, she operated a pilot plant for treating wastewater. Pilgrims Pride processes 300,000 chickens per day. This generates 2,000 cubic metres of wastewater full of grease and blood. For twelve years now, the company has been fermenting the wastewater in lagoons with a total volume of 46,000 cubic metres. It produces 6,000 cubic metres of methane per day. This is enough to cover one-third of the process heat required by the food production facility. Five steam engines generate the heat. More is not possible because all of the wastewater is in use.

“They need a more efficient biogas plant”.

Knowledge transfer from Cottbus For this reason, on company grounds, Violeta Bravo de Sepúlveda integrated and studied a 10 cubic metre pilot reactor in actual plant operation. In contrast to conventional biogas processes, the anaerobic sequencing batch reactor (ASBR) used here offers significant savings for operators using the energy they produce as well as retention time in the digester specific to certain substance groups, which results in considerably higher yields. A similar plant for slaughtering waste was already tested at BTU Cottbus.

“We were able to demonstrate that Pilgrims Pride could cover its entire heat needs with a plant like this”, explains Bravo de Sepúlveda. Now the company is making plans in this direction because this is probably the only way it will be able to meet the coming environmental requirements. But there is not a specific time and financing plan yet.

Violeta Bravo de Sepúlveda is already working on the next project. A biogas plant is supposed to be constructed with feed producer La Perla; at a capacity of 100

million kilowatt hours per year, it will more than cover the company’s entire heat needs. 185,000 tonnes of manure, nearly 4,000 tonne of vegetable waste from greenhouses, and large amounts of used grease and whey are supposed to be fermented. This should reduce methane emissions especially relevant to climate change by 5,300 tonnes.

Among other issues, this project is investigating the development of suitable logistics for transporting the substrates as well as the technical challenges of fermenting them together. Since January 2017, a biogas test plant has been running in the institute laboratory for this investigation. Violeta Bravo de Sepúlveda knows that “used grease produces four times as much methane as manure”.

A trip around the city of Querétaro gives an impressive look at the region’s potential: The Agropark’s sea of greenhouses gleams in the sun. Tomatoes and peppers are grown here for the entire country. Not far away, the legendary monolith Peña de Bernal sits at the horizon. Every year on 21 March, crowds of esoterics gather at the cliffs to take in their energy. But the true mountains of energy rise before the cliffs, at the manure collection spot.

Increasing food production and growing mountains of waste Long trucks tip their beds to unload what they have collected at the cattle ranches in the area. Front loaders shove and layer the brown mass into heaps as tall as houses. The majority of the beef consumed in Mexico is raised here in Ezequiel Montes. Currently, the collected manure is still being used, untreated, as fertilizer on avocado farms. Agriculture is a growing industry in Mexico. And along with it, the amounts of manure and organic wastes. For example, there are already five million farms with about 18 million pigs. Both food production and the generation of wastewater and residential waste are also increasing. 82,000 litres of wastewater are generated in Mexico every second.

And 100,000 tonnes of household garbage every day.

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The Mexican government has made an obligation to reduce the country’s greenhouse gas emissions by 30 percent, with respect to the level in 2000, by the year 2020, and by 50 percent by the year 2050. And the use of methane for energy generation comes into play here, also due to the drastic drop in the price of CO2 certificates.

“Actually, this project should earn money by trading in CO2 certificates”. Rodolfo Montelongo points to three thick, black cylinders used to burn off methane in a controlled manner. They protrude into the blue sky over the landfill site of San Nicolas in the state of Aguascalientes. They were installed in 1998. Ten years later, his employer, the British concern Ylem Energy, decided to invest another five million U.S. dollars and use the methane to generate electricity.

Electricity from landfill gas for Nissan Since December 2011, two Caterpillar generators with a total capacity of 2.4 megawatts have been feeding electricity into the grid. Now the methane from the landfill is only burned off if the generators are not working. 100 percent of the plant’s income comes from the sale of electricity. The Japanese automobile manufacturer Nissan, which runs its production in Mexico in the Aguascalientes industrial park, purchases the 10 gigawatt hours produced per year. Rodolfo Montelongo is a not allowed to say how much Nissan pays per kilowatt hour. Only that they pay less than the price for the industrial operations of the main carrier: i.e. below about 5 euro cents

Biogas Magazine | Edition 05 | 20

per kilowatt hour.

“That is a challenge for us”, says Montelongo during a tour around the landfill. In the open section, waste collection trucks dump out their loads. Collectors search for usable items by hand.

Black plastic tubes snake across the dried out soil of the closed section of the landfill. Up to now, 250 sources of gas in the mountain of waste have been tapped or bored into. “We are always hunting for methane”, explains José Luis Valadez Bustos, the technical director.

The various materials in the waste, the washing out of organic substances due to rain, and temperature fluctuation make gas production unstable. In addition, there are unrepaired cracks through which oxygen enters or delays in sealing up individual sections of the landfill. In San Nicolas, the amount of waste and the capacity of the plant would allow for up to 19 gigawatt hours of electricity per year. Nissan would purchase this power as well. But this potential has not yet been able to be harvested yet.

Eight landfill gas plants in operation In Mexico, methane is used to generate electricity in eight landfills so far. With an installed capacity of 17 megawatts, the largest is in Monterrey.

Starting at a daily volume of 500 tonnes, running a landfill gas plant is worthwhile. Because the trend in Mexico is toward larger landfills, more plants will certainly be established. Ylem Energy is currently building two new landfill gas

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plants. But wouldn’t it be better to work with biogas plants? Rodolfo Montelongo shakes his head. “That would, of course, be efficient and cost-effective, but there isn’t a functioning waste separation system in Mexico”.

Alvaro Zurita and Esteban Salinas, who are working on the project “Using municipal waste to generate energy” for the Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ) affirm that the separation of organic waste is a hurdle that can be overcome. The only biogas plant at a landfill so far has had technical problems due to waste that was insufficiently or unsuitably prepared. The Secretariat of Environment and Natural Resources of Mexico financed the plant in Atlacumulco in the state of Mexico.

In many communities in Mexico, waste disposal is organized by a complex, confusing web of public and private stakeholders. The garbage trucks and their drivers are provided by the communities. The crews on the trucks are private, self-employed people, who also sort out and sell the recyclable waste. Their jobs are in demand and are quietly assigned by the drivers. The drivers, however, are organized in strong unions.

Many collectors who go door to door to homes and businesses on their own with sacks on their backs also make a living from recyclable items.

One look at the surprisingly clean streets of Mexico City demonstrates that the system works somehow. However, the system is so influenced by individual interests that it is difficult to change anything. Moreover, the extremely low landfill fees hinder investment on the part of landfill operators.

Taking care of waste management in Xalapa In cooperation with the Secretariats of Energy and of Environment and Natural Resources, the

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GIZ is attempting to advance the use of waste to generate energy at various levels. For example, Zurita and Salinas are currently consulting on a project in Xalapa in the state Veracruz, where the Inter-American Development Bank is financing a waste fermentation plant at a landfill. “Here, above all, we have to deal with waste management”, says Esteban Salinas A lot in Mexico is in flux; some things are moving in the right direction: the structuring of energy reform, for example, or various environmental requirements and national trading with CO2 certificates, which is currently still in the pilot phase. Some large projects appear regularly in the media without any real progress being made, such as the use of landfill gas at Bordo Poniente – once the largest landfill in the world, closed in 2012 – for the new airport in Mexico City. Or the construction of the world’s largest biogas plant at the large market in the mega-metropolis to make use of the 2,000 tonnes of waste generated daily.

Eugenia Kolb from the German-Mexican Chamber of Industry and Commerce (AHK Mexiko) still sees good opportunities for companies from Germany on the Mexican market for bioenergy. For this reason, the AHK Mexiko offers regular informational events and trips for industry stakeholders Author Klaus Sieg Freelance journalist Rothestr. 66 · 22765 Hamburg, Germany Article was provided by the German Biogas Association (Fachverband Biogas e.V.) Picture Credits : Klaus Sieg

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IBA an

Biogas Magazine | Edition 05 | 20

nd BFI

BENEFITS · To address the waste management (organic waste only) issue via Biogas route. · Supporrng the flagship programmes of Government of India like Swachh Bharat Mission, GOBAR-Dhan Scheme and Smart City. · To increase the awareness about the biogas and to apprise our countrymen about the immense benefit it can offer. · To develop entrepreneurs in the waste to energy sector. · To establish a scalable and economically viable Waste to Energy models. · To depict the wherabouts of organic waste throughout it’s lifecycle by Circular Economy feature of Biogas App.

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Biogas Magazine | Edition 05 | 24

Biogas recovery from ETP saves several latent operational cost

T

he Effluent treatment plant of milk processing unit, confectionary plant, brewery plant, food processing plant, agri processing unit, condensate of distillery unit, sugar industries etc. typically utilizes Up-flow Anaerobic Reactor (UASB) that treats the influent under anaerobic condition and decompose the organic substance through biological activity. This process of treatment removes COD as high as 80 to 90% and generates biogas. Most of the plants as referred above calculate biogas generation potential from the existing UASBR by using following formula.

Biogas generation (M3/d) = [Flow across UASBR (M3/d) X COD reduction across UASBR (Mg/L) X (Specific biogas generation = 0.54) (M3/kg of COD reduction)]/1000.

The methane content in biogas is normally in excess of 60% and it calorific value is more than 5000 Kcal/M3.

This biogas could easily be fired into boiler to replace costly fuel enabling handsome saving.

In cases, where huge biogas potential exists,

electricity generation could also be an option to implement.

Generally, it is noticed that industry owner not having the arrangement to utilize the produced biogas has some kind of arrangement for diverting and flaring biogas before being discharged to atmosphere. This flaring arrangement is in general not maintained properly as its efficient operation has no impact on the final ETP treated water quality. Therefore, plant operation maintenance team ignore the upkeep of flare unit. Under such circumstance, biogas leakage is prominent, which gradually corrodes the surrounding system due to presence of H2S in Biogas.

To our surprise, during a recent visit to a brewery plant, it was noted that biogas hood and channel arrangement at the top of their UASBR is badly corroded and all the gas is leaking in the atmosphere since years. Due to continuous exposure of biogas on the concrete digester wall, the digester is weaken to such an extent that civil structure expert declared that if further corrosion of digester concrete wall is not addressed, the whole digester

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Biogas Magazine | Edition 05 | 25

Author Shailendra Jain Shreyans Energy Pvt. Ltd.

would be unsafe to operate and would need to be replaced.

The simple phenomenon that is taking place is that, cement concrete mortar is alkaline in nature and H2S in presence of moisture form H2SO4 acid that reacts with the alkaline concrete surface and gradually corrodes the surface material. Over a period of time, the reacted surface peels off and steel reinforcement R

get exposed to biogas/H2S, thus continuing to corrode the steel leading to weakened structure following collapse.

Hence, scientific biogas recovery and utilization system in ETP is not only desired to save on cost as a substitute fuel but also to safe guard the surrounding equipment and structure for the aforemetiond reasons.

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Save the date! »Plenary sessions »Biogas worldwide

13 – 16 November 2018 Conference Area in Hall 2, Exhibition Ground in Hanover, Germany

»Workshops »Best Practice »Excursion

World‘s largest meeting of the biogas sector.

With large biogas exhibition in the EnergyDecentral.

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Programme and Registration:

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Biogas Magazine | Edition 05 | 27

Potential of Biogas generation from Municipal Solid Waste: A Case of Ahmedabad City

I

Municipal Solid Waste: A Challenge ndia, second largest populous country with 1.35 billion people comprising 17.5% of entire world population, is sixth-largest and one of the fastest growing economy. We are at a very crucial juncture where we need to analyse the resources available to support our population and ensure we remain sustainable economically, environmentally and technologically to ensure the overall well-being of citizens. Waste generation has become a paramount concern with rapid urbanization. There is increase in representations on MSW management from citizens and Courts / Tribunal where they expect that at least the recently revised SWM Rules 2016 should address their concerns.

Considering the magnitude of the waste generated in Indian context, there is huge potential for power generation from combustible waste; biogas generation and compost production from degradable waste; and material recovery for recycling from plastic and paper dumped at landfill site. If the waste generated is dumped without material and energy recovery, considerable amount of land will be required at regular time intervals increasing the environmental footprint every time.

Our daily national average per capita waste

generation is 0.4 kg which amounts to 0.5 million metric tonne per day (MMTPD) of MSW generation across the nation. Currently, across India, total solid waste disposal through compost and WTE technologies is less than 10% of total waste. That means everyday 90% of waste, which amounts to 0.45 MMTPD is being left untreated which has implications on air, water and land. With this trajectory, we are soon going to end up in a situation where it will take a catastrophic form.

Problems due to Landfilling In the Indian context, combination of the following technologies have been identified for processing of MSW depending on the range of the population, quantity and quality of wastes generated at city level:

- Biomethanation and conventional microbial windrow/mechanized/vermi composting for wet biodegradable wastes.

- Preparation of briquette / pellets / fluff as Refuse Derived Fuel (RDF) and Incineration / Gasification / Pyrolysis for dry high-calorific value combustible wastes.

- Plastic wastes to fuel oil.

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Biogas Magazine | Edition 05 | 28

Loss of Resources

Land/Soil Pollution

Water Pollution Author Dr. Kunal N. Shah Gujrat Energy Research & Management Institute (GERMI)

Air Pollution

Human Safety and Health Hazards Current Solid Waste Management Scenario The foremost step in solid waste management is collection of waste from households and commercial places in urban and rural establishments. Normally, the municipal corporations and Urban Local Bodies across the nation execute collection of MSW through fleet of vehicles. Normally, this MSW is taken to Collection Centres in a city depending on the size of the city. From here the compacting vehicles carry the MSW to landfill site where it is compacted and dumped.

Several scientific reports have indicated that around 35-60% of the MSW received is compostable in nature. Typically, in Indian perspective average 45% organic fraction have been reported. Perhaps this organic content is initially scavenged by stray animals likes dogs at landfill and gradually degraded by aerobic action and finally biomethanation is observed.

Due to biomethanation, the methane during its evolution from the deeper layer gets self-ignited due to increase in temperature by biomethanation and heating of the heap due to sun. This leads to burning of adjoining material which contains plastic, rags, paper and other combustible unsegregable components. Ultimately, there is increase in temperature; evolution of GHG like SO2, NOx, CO2; and particulate matter.

While at places where methane does not reach

- Wet waste decomposes on dump site with dry waste and recoverable dry waste is rendered unsuitable for recycling.

- Recyclable natural resources are dumped and thus lost.

- Demand for virgin materials increases.

- With each day, a portion of land will be converted to dump site reducing availability of usable land.

- Rain water from landfills/dumpsite leatches and destroys the essential component of soil making it infertile.

- Adversely affects biodiversity of an area.

- Rain water from landfills/dumpsite leaches and contaminate surface and ground water sources with chemical species.

- Threatens aquatic life.

- Odour nuisance in nearby areas.

- Harmful greenhouse gases and particulate matter are released from dump sites.

- Dioxins and furans are produced due to open burning of waste.

- Spontaneous fire in landfills due to methane gas is a risk to people living in the vicinity.

- Deaths due to diseases caused by pollution has increased considerably.

higher temperatures failing to self-ignition, it gets evolved in to atmosphere. Overall, there are three losses, viz. the increase in GHG emission, loss of land and loss of potential methane which could be tapped either by landfill gas technology or by subjecting organic component to biogas. In this article, potential of MSW for biogas generation is consisered.   Support from Legal and Policy Framework for implementation of Biomethanation for MSW Management As per SWM Rules, 2016: Clause 4 – Duties of Waste Generator: All gated communities and institutions with more than 5,000 sqm area; resident welfare and market associations; all hotels and restaurants; shall, within one year from the date of notification of these rules and in partnership with the local body, ensure segregation of waste at source by the generators as prescribed in these rules, facilitate collection of segregated waste in separate streams, handover recyclable material to either the authorised waste pickers or the authorizsd recyclers. The biodegradable waste shall be processed, treated and disposed off through composting or biomethanation within the premises as far as possible. The residual waste shall be given to the waste collectors or agency as directed by the local body.

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Biogas Magazine | Edition 05 | 29

Clause 15 Duties and responsibilities of local authorities: Collect waste from vegetable, fruit, flower, meat, poultry and fish market on day to day basis and promote setting up of decentralised compost plant or biomethanation plant at suitable locations in the markets or in the vicinity of markets ensuring hygienic conditions.

Indicative Criteria for Biomethanation of MSW

Criteria

Biomethanation

Technical Criteria

For 300 TPD of segregated/pre-sorted MSW : 2.5 ha of land is required

Land requirement Waste Quantity which can be managed by a single facility Requirement for segregation prior to technology

1 TPD at small scale to 500 at TPD at larger scale Very high

Rejects

About 30% from mixed waste

Potential for Direct Energy Recovery

Yes

Technology Maturity

Feasabillity for biodegradable waste is proven. In case of miixed wste, appropriate presorting has to be carried out.

Financial Criteria Indicative Capital Investment

Typicallty 75-80 Cr. tfor 500 TPD plant.

Market for Product/By-Product

Biogas can be purified and either bottled or fed through pipeline for cooking/heating purpose or fed to gas generator to generate electricity

Managerial Criteria Labour Requirement

Less labour intensive

Predominant skills for Operation and Management

Technically qualified and experienced staff

Environmental Criteria Concerns for toxicity of product Leachate Pollution

The final product is generally applied to soil as a soil conditioner. Can contaminate the food chain if compost is not meeting FCO norms High if not treated properly

Atmospheric Pollution

Low Leakage of biogas is a challenge.

Odour issues.

Other

Fire and safety issues to be taken care of

Potential of Biogas Generation from MSW: Ahmedabad City Case-Study Considering that at least 25% of MSW is organic in nature, and if it can be obtained in segregated form, it can be subjected to biomethanation through a biogas plant. An example of Ahmedabad city (population around 6.3 million) generates around 4000 MT of MSW per day is considered.

An attempt is made to derive an approximate power generation capacity of organic waste generated in Ahmedabad:

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Biogas Magazine | Edition 05 | 30

Parameter

Description

Median Value

X Y Z L W1 W2 h CV P Q P*Q

Biogas produced (m3 per kg of volatile solids per day) Digester Effifciency (%) Total Organic Fraction( %)

0.5 57.5 25 47.5 3750 4.8E-05 0.3 900 128027 0.01308 1675

Organic biodegradable fraction (%) Total Waste generated everyday (MT) constant= (860* 24) Conversion Efficiency (%) of MSW kcal/m3 X x Y x Z x L x W1 x 1000 W2 x CV x h Net Power Generation Potential (KW)

Success stories There are some well-known examples of installation of MSW based biogas plants: (i)16 tonnes MSW plus 4 tonnes per day (TPD) slaughterhouse waste based facility in Vijayawada; (ii)30 TPD flower-fruit market waste based biogas plant in Koyambedu, Chennai; and (iii)500 TPD MSW based facility at Lucknow.

Gaps So far, large biogas plants fed with MSW have not been successful in India although such plants have been successful in some other countries. The failure of MSW based biogas plants is not related to the basic technology; this is more due to lack of understanding of the process and planning capability and due to mismatch between the expectations of the concessionaire

and the consignee with respect to quality and quantity of MSW supply. However, there are ongoing attempts by different urban local bodies (ULBs) to set up MSW based biogas plants.

Medium to large digesters are appropriately designed and engineered for smooth operation.

Epilogue In nutshell, considering the environmental implications related to current MSW management in major cities, collecting waste in segregated form from the source and subjecting it to biomethanation technology will lead to decrease in the land requirement for MSW disposal, curtailing fire on landfill sites, generation of energy from waste and availability of compost for application in gardening and agriculture to increase the soil conditioning over a period of time.

Picture Credits : Dr. Kunal N. Shah

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Figure 1 – Overview of Organic Valorization Center (CVO).

A

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Biogas Plant Case Study from Portugal

marsul is responsible for the management and valorization of Municipal Solid Waste from 9 municipalities of Setubal peninsula, southside of Lisbon and Tagus River. The company belongs to a group named EGF, which also includes similar companies from other Portuguese districts (covering 64% of Portuguese population). EGF group was acquired in 2015 by a private multinational group named Mota Engil, specialized in Engineering, Construction and Transport Concessions, which is investing in the environmental sector.

Among Amarsul facilities, at Seixal Ecopark, there is an Organic Valorization Center (CVO), consisting of a 2.4 MW Biogas Plant coupled with composting processes (figure 1). The holy grail of CVO are 3 horizontal digesters (Kompogas technology) of 1650 m3 fed with a well-defined mixture of organic matter sorted from unsegregated MSW in a pretreatment line, milled green residues and a liquid fraction of clean water and pressed water recirculated from a dehydration station. The exploitation of CVO started in 2015 and since then the process has been improving to reach its maximum capacity.

Currently, 2 of 3 digesters are operating at full

capacity (1300 m3), allowing a daily production of 23 MWh of energy. The 3rd digester is expected to start operating at the end of 2018, inoculated from the 2nd digester.

Pretreatment Line The Pretreatment line was designed to separate as many contaminants as possible, viz. glass, ceramics, stones, metals, bulky materials, etc.

Therefore, its main goal is to obtain a final residue with the highest organic matter content possible in order to feed the digesters. Thus, we usually call this final residue Organic Matter.

The MSW from Almada and Seixal municipalities are discharged by garbage trucks in a 3050 MT reinforced concrete bunker, from which an operator transfers the waste to the beginning of the line using an industrial mechanical claw.

From there, a conveyor belt guides the waste to a manual sorting cabin in which 4 operators manually separate bulky materials and glass.

The first are collected in an open container and dumped on landfill while the second are stocked together with the glass residues recovered from sorted collection to be recycled. After manual sorting, the waste goes through a bag opener.

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Author Diogo A. S. Silva Organic Valorization Center (CVO) – AMARSUL

This equipment consists of a rotor with welded sharp teeth and a fix blade that rip the residue while it is going through. Besides of opening closed and full plastic bags, this equipment is also very important to control the waste flow and to scatter the material to a further conveyor belt. For this, the distance between the rotor teeth and the fix blade can be adjusted from 5 to 120 mm.

The scattered waste keeps going through the line to a trommel, a rotating cylindrical sieve conceived

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to sort the waste by size in two fractions: the residue of interest with small size (< 75 mm) and the reject with bigger size (> 75 mm). The rotary drum has a slope of 4â ° and the residue is fed at its highest point. Then, while the sieved drum is rotating, the residue flows from the highest to the lowest point. The fraction of interest is sieved and collected throughout the drum to a conveyor belt located below the trommel which flows in the opposite direction. The rejected fraction reaches the lowest point of the drum and flows through a conveyor belt to a compacting press located outside the Pretreatment building, where it is pressed in a closed container to be dumped on landfill. In between the conveyor belt, there is a magnet to recover ferrous metals to be recycled. Three closed containers are reserved to the compacting press in a system that permits the exchange between a full and an empty container, allowing the operation of the pretreatment line while the full container is being dumped on landfill.

The fraction of interest then goes through another magnet to recover small size (< 75 mm) ferrous metals for recycling. Then there is an Eddy Current Separator (ECS) to recover non-ferrous metallic components for recycling, such as aluminum and brass. A vibrating plate is located before the ECS to scatter the residue and improve its efficiency. At the end of the conveyor belt, non-ferrous metals suffer a repulsive effect of an electromagnetic field, jumping a certain distance to a channel that ends in an open container to collect them.

One the other hand the trajectory of the rest of the residue is not influenced and it falls naturally to another conveyor belt. Before being called Organic Matter, the waste has a final separation step in an equipment named Inert Separator (IS), which was designed to separate hard and heavy remaining contaminants (viz. glass, ceramics, stones, metals, etc.) that might have escaped through all previous separation steps and affect the final organic matter content of the residue. At the IS, the hopper where the residue falls has a sloped deflector plate that drives the residue to a drum which rotates towards the material inlet. When hard and heavy contaminants hit the plate, they are projected in the opposite direction of the rotating drum, being separated from the finer fraction of the residue and collected in an open container, while the residue of interest is driven by the drum rotation and finally flows through consecutive conveyor belts to a storage bunker. In between, a fraction of milled green residues is added, which importance will be discussed below. The separation efficiency of the IS is not very high, and unfortunately there is a small percentage of contaminants that remain in the Organic Matter. Even so, in order to optimize the IS efficiency, the slope and the high of the deflector plate can be adjusted. As a measure of process control of the Pretreatment line, samples of Organic Matter are frequently collected to be characterized, especially to determine the content of significant contaminants (size > 2 mm).

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Digestion Technology The Organic Matter is stored in 3 bunkers (one per digester) waiting to be mixed and fed to the digesters. The process occurring inside the horizontal digesters (Figure 2) is called anaerobic digestion (AD), a complex biological process including a large community of bacteria, in which methanogenic bacteria produces the gold: methane, the most valuable component of biogas with high calorific value.

Figure 2 – Backside view of the digesters (extraction side).

At CVO the digesters operating process is a thermophilic (52-54 ⁰C) dry AD, meaning that the digesters input has a high content of solids (2040% TS). Therefore, in order to fulfill the optimal solids content, the feeding mixture is carefully and remotely planned and controlled. Each one of the 3 mixers (one per digester), which are coupled to the storage bunkers, is equipped with a digital balance, so the feeding mixture “recipe” is programed and controlled by weight. The feeding mixture has a liquid and a solid fraction: the liquid fraction is composed of clean water and a portion of pressed water recirculated from the dehydration station (see below) in a well-defined proportion, accounting for 25-35% (w/w) of the mixture; the solid fraction is composed of stored Organic Matter enriched with milled green residues (ca. 10% w/w) accounting for 65-75% (w/w) of the mixture. Milled green residues are crucial for the AD process in order to control the Carbon to Nitrogen (C/N) ratio and also to give density and viscosity to the digestate, avoiding the deposition of dense contaminants on the bottom of the digester.

The feeding process works with a hydraulic system

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of pumps and valves. A feeding mixture cycle starts with the mixer empty. First a programmed weight of liquid fraction is added: clean water by opening a valve and then pressed water pumped from the dehydration station. Afterwards, the Organic Matter is gradually added from the bunker to the mixer. A hydraulic system is responsible for the movement of three steel beams (in opposite directions) located at the floor of each bunker, and in between plates move the Organic Matter towards the coupled mixer. The hydraulic system stops (and so the floor) when the programmed weight of Organic Matter per mixture is reached in the mixer.

During the addition of Organic Matter and before start pumping the mixture to the digesters, two screws located at the bottom of the mixer allow a good homogenization of the mixture.

The feeding step is guaranteed by a piston pump working with an automated valve system.

The operation of the digesters is continuously monitored, including specific AD parameters as retention time, organic loading rate, solid content, ammonia concentration, FOSTAC value, etc. Additionally, on a monthly basis, samples from the digesters are sent to external laboratories to determine other parameters which give us a full picture of the digesters operation.

Biogas Treatment and Energy production In 2017, an average specific biogas production of 131 Nm3 biogas/ton OM was recorded at CVO digesters. As mentioned before, 2 of 3 digesters are operating since 2016, and they reached the full capacity in last October, with a feeding rate of 40 ton OM/day. digester and a retention time of 23 days. The production of biogas is continuously monitored by gas flowmeters, as well as its quality by using a biogas analyzer to determine the content of methane, oxygen, hydrogen and sulfuric gas, every 4 hours. Before feeding the Power Generators, the biogas passes through a Biogas Treatment Station to essentially remove humidity in a heat exchanger and contaminants as Ammonia and Sulfuric gas in activated carbon filters. CVO counts with 3 Power Generators of 800 KW, two of which to produce electricity and a third to be used during maintenance periods. The operation of Power Generators is automatically controlled by the biogas pressure produced in the digesters, so the energy production of CVO is currently maximized for the two digesters in operation.

Composting Process As for feeding the digesters, the digestate

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extraction is guaranteed by a hydraulic system of valves and piston pumps towards a dehydration station. There, the digestate from the 1st and 2nd digesters is fed to a dewatering screw press where it is dehydrated. A parallel dewatering screw press is in place to be used with the 3rd digester. The pressed water is stored in storage tanks and part of it is recirculated to the feeding mixers, as men-

Figure 3 - CVOâ&#x20AC;&#x2122;s Intensive Composting Tunnels view

tioned above. The dehydrated digestate together with the reject from the Inert Separator, which was found to still have a certain organic matter content, are mixed in a 1:1 proportion to start the composting process.

The composting process starts inside one of ten CVOâ&#x20AC;&#x2122;s Intensive Composting Tunnels, (figure 3).

A tunnel is filled by an operator by using a wheel loader and once full the door is closed and the

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composting process starts. The key parameters to control the process are ventilation (and the presence of oxygen) and temperature. Each tunnel is equipped with a fan that continuously feed the tunnel with a defined proportion of fresh and recirculated air in upwards direction.

An oxygen sensor located in the feeding air duct allows the control the oxygen content. On the other hand two temperature sensors are stuck inside the composting pile, allowing the temperature control along each composting cycle. Every composting pile does 3 week cycles inside a tunnel, meaning that after a cycle of 7 days the composting pile is transferred to an empty tunnel. This revolving process permits a better homogenization and full ventilation of the composting pile. At the end of the 3rd cycle, the composting pile is transferred to the composting park where it keeps composting for a month. From here the revolving step is done every 2 weeks and it is guaranteed by a specific revolving machine designed for this practice. Finally, at the end of the composting process, an operator feeds the composting pile to the composting refinement station using a wheel loader. Along the station, there is a vibrating sieve to separate big size materials (> 12 mm) and a densimetric table (with dust capture in a cyclone) in which an upwards air flow blows the final compost to a conveyor belt to be collected in an open container, while heavier materials (as glass and stones) stay at the bottom of the table and are rejected. Both rejected streams are guided towards two different open containers to finally be dumped on landfill. The final compost is stored to be sold for agricultural practices.

DISCLAIMER Articles published in the newsletter are individual views of respective authors. IBA has only provided a platform to share their views. IBA is not responsible for the content/images of the articles.

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Biogas Magazine | Edition 05 | 38

R&D landscape of Biogas in India

T

he global biogas journey began in India in the late eighteenth century at Matunga, Mumbai, wherein biogas was used for lighting purpose. Thereafter, the concept of biogas gained much traction world-wide, because of its promise to meet dual demands-as fuel and fertilizer along with scientific treatment of waste. However, despite the potential to produce and use biogas in India, to say the least, the movement so far hasnâ&#x20AC;&#x2122;t really lived up to its true potential.

In real terms, the journey of biogas in India gathered momentum during the mid-nineteenth century, wherein several models featuring fixed dome and floating dome technology customized to local requirements were developed. The further growth story began from 1980 onwards, with a newly carved out Department of Non-Conventional Energy Sources (DNES), now Ministry of New and Renewable Energy (MNRE) provided thrust to the construction of small household

based plants through its flagship program NBMMP (National Biogas and Manure Management Program). With DNES getting actively involved, the era also saw some research work being carried out alongside expansion in the ambit of biogas through establishment of medium scale (institutional and community scale) biogas plants. All this while, the primary focus area of research activities converged on improvement in design and efficiency of biogas burners, or the cooking stoves, and minor design developments in design of small-scale digesters. With sparse involvement from academic institutions, even in the late nineteenth century, the technological development for the industrial scale of biogas production happened at a slower pace.

In the yester years, traditionally the feedstock used for biogas production had been predominantly cattle manure. However, the early twentieth century saw India bringing innovation into biogas by exploring new and unique feed options

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such as rotten potatoes, vegetable waste, fruit waste, rotten grains, agricultural waste, and industrial waste (press mud, food processing waste, spent liquors, etc.). Still, with feedstock used in India differently compared to that used globally, many research institutes focused on characterization studies of potential feedstocks, both from its biogas potential and utility of the unspent bio-slurry as organic fertilizer. Coffee husk, for instance is an interesting agro-industrial waste, which resists bio methanation due to acidic pH and the presence of polyphenols.

Indian Institute of Science (IISc) carried out extensive research on coffee waste around 201011 and reported positive results for potentially taking it to commercial scale.

Recently, Government of India (GOI) made many bold announcements in the energy domain, like electrification of villages by 2018, and universal electrification with 24x7 electricity by 2022, targeting reduction of oil imports by 10% from 2014-15 levels, by 2022, and so on. At global forum as well, India has set voluntary ambitious targets of 175 GW renewable energy capacity

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addition by 2022 with a contribution of 10 GW from biomass, which includes biogas. The present cumulative installed capacity of biogas plants lag significantly behind at less than one GWeq. Thus, from policy standpoint, the need to refocus attention on Research, Design & Development and Demonstration (RDD&D) in biogas has arisen even more to supplement energy supply in the country, and propelling biogas industry to become competitive and self-sustainable.

As reported by MNRE, presently (2018), many premier academic institutions including the IITs (Indian Institute of Technology), and deemed Universities are involved in biogas related research work. The area of research spans diverse innovative areas across biogas value chain, such as use of ultrasonic waves for slurry homogenization, refrigeration using waste heat, improving efficiency of gensets producing power using biogas, design & development of prefabricated high rate digester for rapid biogas production, development of anaerobic technology for biogas recovery and stabilization of unsorted municipal solid waste, characterization of bio-slurry as po-

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RDD&D project. Some of the burning contemporary issues that need attention right away feature, scientific processing of the ever-growing problem of MSW (Municipal Solid Waste) through bio-methanation route, treatment of harvested agro-residues which is being openly burnt in fields causing air-pollution, integrating the biogas with biofuels production through biorefineries, and so on. Corporates needs to actively come forward to foster partnership with the research institutes and pave the way towards addressing such real challenges.

In the fore coming years, roping in international cooperation in RDD&D projects should be the focus of policymakers, so as to avoid reinventing the wheel and lever upon the expertise and experience of other countries to explore advanced areas in the field of biogas. One such instance is setting -up and managing an upcoming Biogas Lab at one of the premier institutes in India, IIT-BHU, Varanasi by the Indian Biogas Author Association in cooperation with the German Biogas Association and Abhijeet Mukherjee field experts from Germany. The lab is proposed to come up in 2018, Indian Biogas Association and shall be equipped comprehensively with contemporary testing facilities, like determining composition and yield from various substrates, laboratory fermentation tests of co-substrates, determining environmental and nutrient requirements for substrate degradation, identifying potential inhibitors in biogas processes, evaluation and interpretation of the analysis results, discussion of suggested measures for the Biogas plant to improve performance, and potential incubator for onward R&D activities. tential organic fertilizer, co-generation of biofuels and biogas from biomass, alternative utilization of bio slurry to grow algae mass with onward biogas production, harnessing energy potential from lingo-cellulosic feedstock, and so on.

In nutshell, the ecosystem for RDD&D activities in biogas looks conducive in terms of the defined problem statements w.r.t current burning issues seeking immediate attention, adequate availability of resources, along with the positive intent of the policymakers. However, on certain fronts such as collaboration with national/international institutes, increased participation from corporates, there still remains huge scope for improvement.

Presently, the typical setting of RDD&D projects happens to be on an individual basis by academic institutes depending upon specialization of its research professionals and their area of interest, or in partnership with corporate players.

Joint participation of academic institutes in research work is an extremely rare scenario in Indian context. Nevertheless, most of the research projects are supported by government bodies, like Department of Science and Technology (DST) in coordination with MNRE have specifically earmarked funds for such initiatives.

RDD&D projects should be aligned with contemporary industry requirement and impending issues on hand.

This ensures that industry is involved right from the conception stage of any undertaken

Biogas lab at IIT-BHU

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