Bio-Digesters in India: Nothing Wasted, A Lot More Gained

Bio-Digesters in India: Nothing Wasted, A Lot More Gained
by Kimberley D. Mok, Montreal, Canada on 06.26.07
Business & Politics (news)

In the tropical green south Indian state of Kerala, there is a fresh strategy of dealing with an old problem of waste: specially designed, efficient organic 'digesters' that turn solid waste into energy.

Beginning in 1994, a local NGO called Bio-tech pioneered the development of their ‘integrated waste recycling plant,’ where large amounts of organic waste generated by the markets, slaughter houses, and restaurant kitchens are treated and converted into methane (cooking gas) and fertilizer.

Saji Das, the man behind Bio-tech, then chose town of Kadakkal in Kollam district (which fortuitously had the largest dump in the state) as the location for the first integrated recycling plant. Today, the plant is capable of digesting daily one tonne of waste – producing three kilowatts of energy – enough to power 120 street lamps.

The conversion process begins with the manual segregation of wet waste, dry biodegradable waste and recyclable solids like glass, metal and plastic. The plant utilizes five technologies in order to complete the transformation of waste to energy in the form of biogas, namely biomethanization, biocineration, leach beds, waste water treatment and vermicomposting.

Wet waste – including blood and other waste matter from the slaughter house – is critical in producing biogas and is actually run through a pre-digester in order to boost the bacterial action that will break the waste down further. Once the process is complete, it generates biogas that can be used as fuel, in addition to electricity used for lighting and organic NPK (Nitrogen-Phosphorus-Potash mix) fertilizer.

No waste is left behind, as the different components of the Bio-tech integrated recycling plant are designed to address specific types of waste, which distinguishes them from traditional, less-efficient treatment plants. For instance, the biocinerator unit is designed to handle wastes that degrade slowly, such as paper, dry leaves and plants, while the biomethanization unit processes all organic waste. The leach beds dispense with vegetable matter. Anaerobic waste treatment takes place in another separate unit and the final process incorporates earthworm action in a vermicompost unit.

Back at Kadakkal, this thorough efficiency is reflected in the reuse of water that is extracted and recycled so that it can be sent back to flush out abattoirs. Electricity produced by the plant is used to run all the equipment, while the incinerator runs only on the biogas produced by the methanization unit.

Das has now set up ten such integrated plants all over Kerala. In towns such as Kumbalangi, environmentalism and tourism have joined forces in transforming it into a “model tourism village” where, with government support, 140 Biotech domestic units have been designed to run on human waste from lavatories, in addition to 800 units that convert biogas from other wastes. Other municipalities, such as the tourist-friendly Kovalam, are following suit as well.

In the larger scheme of things, these integrated recycling plants make conventional, centralized garbage disposal systems look like, well, junk. There is no need to address the challenges of collection and transportation and all maintenance happens on-site. The units themselves can be tailored to suit the requirements of the customer and the domestic version only needs one square metre of space – and manages both solid and liquid waste at the same time. Costs to imported Liquefied Petroleum Gas (LPG) for cooking are saved.

In a state where its ‘Annual Economic Review’ published by the government shows that only 50 per cent of the 2,500 tonnes of waste created per day in Kerala is collected for disposal – and where the tourism industry generates additionally one tonne of waste daily – the bio-waste digesters are looking like an ecologically-effective and versatile way around the looming spectre of the waste problem in India and beyond.::InterPress Service

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[5] Comments | Related Tags: Bio-tech | biogas | india | integrated waste recycling
Comments (5)
I live in New Delhi region and have been seriously considering installing Biotech's residential system which costs around just $232 (without rebates). It has a 1 cubic meter capacity and can supply gas for 1-2 hours' operation a day. Combining it with solar cooking I think one can be completely off fossil fuels as far as cooking is concerned.

By the way, Saji Das (Biotech) just won the Ashden Award a few days ago. I wonder when will Treehugger cover the awards.
June 27, 2007 3:54 AM | flag a problem
Manu Sharma says:
Hi Manu,

I see that an article on the Ashdens was published today here.

On a side note, another Indian from Karnataka won an Ashden... wonderful to see this!
June 27, 2007 6:03 AM | flag a problem
Kimberley says:
Definitly this has worked out among so many areas in Kerala,South india.
Specially where people have cows,waste foods,leaves,Rubber waste water any thing .One more advantage is that u can dump any thing that is decomposble in this pit.
comparing the cost of One govt supplied LPG cylinder costs INR 270 .Initial implenatation for whole pit is INR 6000,then up to 20 years no need to look any thing.Its all maintainance free.
Also I heard govt are giving subsidies for this plants.All you need is 1.5 meters diameter mesh and some concrete mixs.one out inlet,one out let and top a hole for gas to come out.
Simple stuff.
June 27, 2007 6:43 AM | flag a problem
sreyass says:
Hi Kim,

I'm aware of that post from May that covered the finalists. The winners have just been announced on 24th June. And yes, there were actually three entries from India winning awards this year. It's not the first time either, two of them (Biotech & Selco) have won awards in the past as well.

Ashden encourages companies that invest money won from their awards back into their businesses.
June 29, 2007 3:07 PM | flag a problem
Manu Sharma says:
In case anyone in India or elsewhere wish to contact Biotechm here is their contact info

BIOTECH
PB No 520
MP Appan Road
Vazhuthacadu
Thyncaud PO
Thiruvananthapuram
Kerala. India 695 014

Telephone: +91-471-2332179, +91-471-2321909

Email: biotechindia@eth.net

February 27, 2008 4:43 AM | flag a problem
Manu Sharma says: