- 25% of the toilets in Maharashtra’s Kolhapur district are linked to biogas units that convert the waste to fuel while tackling faecal sludge on the spot.
- This is significant given that in general in India, there is a taboo attached to using human excreta to generate biogas, which is then used in cooking.
- Highly subsidised competing schemes for cooking fuel, fertilisers, and sanitation in India, along with low technical know-how, also contribute to its low adaptation.
Since the time she got married, 35-year-old Rupali Choudhary has spent a significant amount of her time every day, cooking for the family. She would go to a forest near her village, three times a day, to collect firewood for cooking. In 2018, these trips reduced, freeing up some time, after a biogas plant was installed in her backyard. Cooking could now be done on the biogas-powered cookstove and was smoke-free, while also reducing dependence on firewood.
The cookstove is powered by biogas from the biogas plant that is connected to the newly constructed toilet in her house. As many as 60 of the 100 families in her village Chaudharwadi in Kolhapur district of the western state of Maharashtra, have linked their toilets to biogas digesters where organic matter from the toilets generates biogas as it decomposes.
This also means that Choudhary doesn’t have to go to the common public toilet every day for defaecation. “I spend more time in the fields now. The slurry from the plant makes good manure which we use in our two-acre sugarcane plantation. The expenditure on urea has come down as a result,” says Choudhary. “Biogas-linked toilets have been life-changing for our women who carry the burden of work when it comes to cooking and firewood collection and even risk safety when going out of home for defaecation,” said Gauri P. Mathapati, Agricultural Officer of Kolhapur.
Around 25% of toilets in Kolhapur – 1,19, 780 out of 5,30,000 – are linked to biogas plants. The district has ranked first in the country several times and in Maharashtra since 1982 for achieving targets in the construction of biogas digestors. As many as 12 of the 1186 villages in Kolhapur have 100% coverage of biogas-linked toilets (BLTs).
The initiative to link existing or new toilets to biogas plants was started by the district administration in Kolhapur when the Swachh Bharat Abhiyan, a national sanitation project, was launched in 2014. The government offers a subsidy of about 30% of the estimated expenditure, to incentivise people to set up biogas-linked toilets.
But the initiative has had its challenges, primarily, one of behavioural change. “Toilets trigger a feeling of disgust in people. Mindset change to think of faecal matter as a resource was the biggest hurdle in the process. But a rigorous awareness programme helped,” said Vijay Patil, District Programme Manager (District Water and Sanitation Mission), Kolhapur.
India was declared open defaecation-free in 2019. But there is still no sewerage network in rural India. Out of six lakh villages in India, only 1.36 lakhs have some arrangement for liquid waste management, mostly twin pits or a single pit that needs to be emptied every few years. And this has emerged as the biggest impediment to using toilets, according to a 2018 study in Bihar. Some villages transport the emptied-out faecal sludge to treatment plants in nearby urban areas but that is an expensive affair. “On-site management is crucial to deal with human excreta because that is the only way value can be created out of it. BLTs can be set up in any terrain and are especially good for water-logged areas,” said Sushmita Sengupta, Senior Programme Manager, Centre for Science and Environment (CSE), a New Delhi-based think-tank.
Read more: Lack of market support for bio-manure hindering growth of compressed biogas plants
Fuel from waste
A typical biogas plant in India has cow dung as its main feedstock and consists of three parts – an inlet from where dung mixed with water is fed, a digester, and an outlet connected to a slurry collection tank. The human toilet is directly connected to the digester via a PVC pipeline and does not require manual handling.
Biogas, comprising 55-65% methane, 35-44% carbon dioxide, and traces, is produced as the organic matter decomposes and is piped from the top of the digester to the cooking stove. The increased pressure from the gas forces out the slurry, the by-product of the process, into the slurry storage tank. The slurry, retained in the digester for 20-30 days, decomposes most pathogens and weed seeds, making nitrogen-rich manure. Biogas is derived from waste, unlike bioethanol or bio-diesel, so it does not involve competition with land and biodiversity for food products.
Biogas plants that operate only on human excreta are not sustainable for household purposes as feedstock is too low to produce an adequate amount of gas. A mix of cow dung and human excreta are more efficient. “One kilogram of cow dung produces 40 litres of biogas while a kg of human excreta produces 70 litres of gas. So naturally, there is higher availability of cooking fuel per day (if a mix of cow dung and human excreta is used),” said R.P. Nilkanth, managing director of Shivsadan Sehkari Society, an agency that supplies prefabricated biogas plants in Kolhapur.
A basic biogas unit of two cubic meters/day (2000 litres) capacity, which is enough for a family of five for its daily use, requires dung from 4-5 cattle and human excreta every day. “Over a month, a two cubic metre plant can produce 60 cubic metres of biogas equivalent to 26 kgs of LPG, 88 kg of charcoal or 210 kg of firewood. If a family uses one LPG cylinder a month and shifts to BLT, it will save Rs. 12,000 annually,” says a report Big Change is possible, a compendium of successful case studies on rural water supply and wastewater management, by the Centre for Science and Environment (CSE).
Progress in Kolhapur
Dhundawade village in the Gaganbawada block of Kolhapur has 60 families, all of whom had BLTs by 2021. “Gaganbawada gets the highest rainfall after Meghalaya. During monsoon, it became difficult to keep the firewood dry,” said Sarjarav Chaudhary, the Sarpanch of Dhundawade. The first BLT was installed in Dhundawade 15 years ago. “People saw the benefits. We needed 500 kgs of urea in one acre of paddy field earlier. With the use of slurry, only 150 kgs are needed now. Some people got LPG connections recently, but even they have given that up now as there is enough biogas to sustain the entire day’s cooking,” he said.
Kolhapur has a shallow water table and experiences periodic flooding. “Having a deep pit for sewage collection would contaminate water here,” said Prakash S. Patil of Padali Khu village, where 250 of the 1700 households have BLTs. The leaching of faecal waste from pits and thus the risk of pathogens contaminating drinking water sources is common in areas with a high groundwater table or monsoon rains, says a 2019 study, When the pits fill up: (in)visible flows of waste in urban India by water and sanitation researchers C. S. Sharada Prasad and Isha Ray.
Uma Jadhav, an agricultural labourer, even increased her earnings after she got a BLT two years ago. “Surplus time meant I could take up more work,” she said. Around 2000 of the 3000 families in her village Sangarol have installed BLTs. “The rest do not have space in the house, so they are compelled to have septic tanks,” she says.
“We are an agrarian economy. Every house has enough cattle to sustain a biogas plant,” said Patil. When the campaign for open defaecation-free villages first started, people were more inclined towards the septic tank. But when they realised that it would mean emptying the pits every few years, they agreed to shift to BLTs,” he said.
Kolhapur has set itself a target of 1000 BLTs this year, in comparison to 250 units in other districts of Maharashtra. “It is not dirty. After all, everything burns in the flame,” said Chaudhary when asked if she was ever against using biogas produced from her toilet.
Mathapati, however, said they are still having difficulty convincing certain communities in Shirol and Hatkanagale blocks. “They have all the means, land, cattle, and funds to install a BLT but do not want to do so. They feel food cooked on biogas is impure. We told them that according to the Vedas, “Agni” (fire) purifies everything. In fact, they are committing violence if they cut trees for wood. But they do not agree,” she said.
District Programme Manager Patil cited an instance when a committee of officials from outside Maharashtra came to check on the implementation of Nirmal Gram, a sanitation scheme, in Kolhapur in 2011. The officials refused to have tea made on a stove linked to BLT. “If that is the attitude of officials in the sanitation department, how can we expect unaware people to adopt this technology,” he said.
Biogas technology received increased attention in India after the first oil crisis in the 1970s, when it was evident that commercial energy would remain outside the economic reach of the rural as well as the urban poor. The National Biogas Development Programme started in 1981 to give subsidies to encourage biogas plants, as a way to make energy more accessible and alleviate the impacts of the crisis. It is now called the New National Biogas and Organic Manure Programme.
With a bovine population of 300 million, which is the source of feedstock for biogas plants, India has the potential of setting up more than 12 million biogas units. To date, five million plants have been installed in the country.
For BLTs specifically, there is no official record of how many exist in India. In 2020-21, the Ministry of New and Renewable Energy targetted setting up 8450 such biogas toilets, 14% of its annual target of 60,000 biogas plants.
The government offers a subsidy of Rs. 14,350 for a two cubic metre biogas plant along with an additional Rs. 1,600 for connecting it to the toilet. The subsidy is about 30% of the estimated expenditure of Rs. 50,000. Yet, the uptake is not as expected.
Dhirendra and Smita Soneji, engineering professors turned farmers, in Gujarat’s Narmada district, became village-level supervisors with Prayas, an NGO that installed biogas plants in Gujarat in 1986 and linked the biogas units to toilets. “But nobody used those toilets. They would store wood or farming tools in them but never used it for defaecation,” they said.
A 2022 study conducted in Assam, by researchers from the state and the United Kingdom, deconstructs the reasons for reluctance to adopt BLTs into technical, socio-cultural and socio-technical. According to the study, the socio-cultural reasons are rooted in the caste system in India that divides society on the basis of occupations and the perception of purity and pollution. Study participants shared perceptions such as BLTs are against religious practice, it is a sin to cook food on a BLT, it is a crime to mix cow dung with human excreta, elderly people in the family won’t accept it, relatives won’t eat at their house. They will be excluded from their caste or village if people discover they are using BLT. The study found that a lack of knowledge and experience as to how a BLT works reinforce these beliefs.
The socio-technical reasons mentioned in the study are that the food will smell of a toilet, the visualisation of food being cooked on toilet gas is abhorrent, maintaining BLTs is a dirty job, and eating food cooked on biogas is ritually and physically polluting.
The participants, however, felt that anonymity about the fuel source might make people used to BLTs. “It is like farmers buying manure from sewage treatment plants to spread it in their fields but not wanting to handle the organic manure coming out of their biogas plant,” said Pradeep Acharya, former assistant professor at the Department of Biogas Research and Microbiology at Gujarat Vidyapith, Ahmedabad and presently a consultant on BLTs.
Another reason for the low acceptability of BLTs is no perceived necessity. The services offered by BLT- cooking fuel, fertiliser and sanitation find competition in subsidised and fossil fuel-based LPG and chemical fertilisers and the Government’s Swachch Bharat Mission, which has BLTs as a component but focuses mainly on basic pit latrines.
Capital cost, less know-how about maintenance of the biogas plant, and the government’s inability to reach the right beneficiaries have affected the success of biogas, says Prateek Shilpkar, assistant professor at the Department of Biogas and Microbiology at Gujarat Vidyapith. “Biogas is a perfect circular technology, but it should reach the needy people, those who still depend on firewood and do not have a toilet,” he said.
A biogas plant requires regular maintenance- adequate water, daily feeding of dung, no use of acidic toilet cleaners, periodic cleaning and stirring, proper sunlight or hot water in winter when microbial action slows down- a task people find cumbersome. The lack of trained masons to repair the plant when it has fallen into disuse adds to the problem.
Because of the rising prices of concrete, the capital cost of a two cubic metre biogas plant is above Rs 50,000. “They should give at least 50% subsidy so that people come forward. The cost of the toilet adds up too. Though the government gives a subsidy of Rs. 12,000 for the toilet, the entire cost of the set-up is more than 2-3 months’ income of most people,” said Uttam Nigade, a turn-key worker who has been installing biogas plants in Kolhapur since 1997.
Banner image: One of the beneficiaries of the biogas-linked toilet scheme in Kolhapur. Photo by Agricultural Officer, Zila Parishad, Kolhapur.