Biogas – from your kitchen, in your backyard

By V. Vijayalakshmi, IANS

Pune : Think twice before you dump that banana peel or spinach stem into the bin. That and more waste from your kitchen can be converted into biogas to supplement your energy needs — that too in your own backyard.

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Anand Karve, director of the Pune-based Appropriate Rural Technology Institute (ARTI), tells you how.

All one needs for the kit is two 1,000 cubic litres of plastic tanks (equivalent to the common syntax tanks seen in most households) and a daily supply of kitchen waste. And homemade biogas, essentially a combination of methane and carbon dioxide, is ready to be used as fuel.

It took Karve almost three years to develop the compact biogas plant system and convince Indian scientists that kitchen waste was a more efficient source of methane than cow dung, the traditional source of biogas.

“One kg of kitchen waste in 24 hours can produce the same amount of biogas as 40 kg of cow dung in 40 days. That means more than 400 times efficiency can be achieved by using kitchen waste as compared to cow dung,” Karve told IANS.

Karve found that methane-producing bacteria belonged to a group called archebacteria or ancient bacteria, which evolved on earth when there was no oxygen. The only places where the bacteria can be found are in the intestines of animals and the bottom of the sea.

That set Karve thinking. “I realised that the bacteria eats what we eat and is thrown out along with the faecal matter. That is why I started using waste food as a source of biogas,” he said.

Karve’s kit has two air-sealed tanks, one on top of the other. The archebacteria that breaks down the waste will only work if it is completely airtight.

According to Karve, it is a myth that cow dung is the only source of biogas. In fact, he said, dung does not have methanogenic bacteria – some bacteria have to be added to the dung to produce biogas.

Karve recommends that the system be installed either on the terrace or in the backyard where there is ample sunshine, because the bacteria perform better when the temperature is higher.

He said it is ideal for restaurants and hostels where there is a large amount kitchen waste and also offers an efficient garbage disposal mechanism.

The costs are minimal and the kit can be installed within a budget of Rs.6,000.

The invention has earned Karve global appreciation, he is a two-time winner of the prestigious Ashden Award, popularly known as the ‘Green Oscars’. He is also winner of the 2007 Jamnalal Bajaj Award for application of science and technology for rural development.

“Initially no one wanted to listen to me, but when the west recognises it people start looking at you.”

Now Karve and his team of 40 have successfully installed about 3,000 plants in India and 2,000 overseas.

In Pune, many hostels and restaurants have started using the system, thus considerably bringing down the use of liquefied petroleum gas (LPG).

According to Karve, 800 tonnes of agri-waste is generated in India annually; this can easily be converted into high-grade energy. “Methane can also be used to drive vehicles. Just like green revolution made us food sufficient, using agri waste to produce methane can make us energy sufficient.”