Sintex's Biogas Digester Ingests Crap, Emits Energy

Plastics maker Sintex seeks to solve India's energy and sanitation problems in one stroke - with an at-home biogas digester. By Jeremy Kahn

The Sintex digester can turn manure into fuel for cooking and electricity.

(Fortune Magazine) -- Sintex Industries, a plastics and textiles manufacturer in Gujarat, India, is betting it can find profit in human waste. Its new biogas digester turns human excrement, cow dung, or kitchen garbage into fuel that can be used for cooking or generating electricity, simultaneously addressing two of India's major needs: energy and sanitation.

Copyright Sintex

Sintex's digester uses bacteria to break down waste into sludge, much like a septic tank. In the process, the bacteria emit gases, mostly methane. But instead of being vented into the air, they are piped into a storage canister.

A one-cubic-meter digester, primed with cow dung to provide bacteria, can convert the waste generated by a four-person family into enough gas to cook all its meals and provide sludge for fertilizer. A model this size costs about $425 but will pay for itself in energy savings in less than two years.

That's still a high price for most Indians, even though the government recently agreed to subsidize about a third of the cost for these family-sized units. "We want to create a new industry for portable sanitation in India that's not available now," says S.B. Dangayach, Sintex's managing director.

Sintex Industries' aptly-dubbed biogas digester is most certainly not the first of its kind, but it is somewhat commendable that its maker is making no bones about this thing's purpose.

Destined to "solve India's energy and sanitation problems in one stroke," this concoction can convert "human [waste], cow dung, or kitchen garbage into fuel that can be used for cooking or generating electricity."

Reportedly, a one-cubic-meter digester would sell for around $425, but could pay for itself in energy savings in under 24 months. Excrement to energy -- now there's a concept.

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