Turning human waste in energy – 27 February 2008

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, which are energy and sanitation. 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.