Biogas

Posted: 7 November 2000

Most of India's one million villages are connected to the country's national electricity grid but the supply is notoriously unreliable. Nowadays though, as Michelle Maillet's informative documentary shows, when the lights flicker off, many of India's rural population now have an independent power backup - and it runs on cow dung.

The 23-minute film, Biogas, visits the state of Gujerat, where many families and villages now have their own biogas plant. It shows how villagers collect all their waste organic material like animal dung, human waste and vegetable matter into an airtight concrete tank, where bacteria slowly digest it to produce a gas which is roughly 60 per cent methane and 40 per cent carbon dioxide. The gas is then piped to the house to be used directly for cooking and heating, or to run electricity generators.

Making dung cakes for fuelKim Naylor/Christian Aid/Still Pictures

Despite its origins, the gas is completely clean, odourless and atmospherically friendly - it keeps carbon dioxide emissions neutral and emits no sulphur. Cooking with clean-burning gas, rather than smoky wood, improves respiratory health and reduces the pressure on fuelwood. Even the sludge that comes out at the end makes an excellent fertiliser.

But biogas is taking off in many other parts of India. In towns and cities where waste is available in bulk quantities, biogas production plants can operate on a much bigger scale. At the Pumjee Paper Mills in Poona, they have incorporated biogas into their production processes, to cut back on their energy bills and pollution. The factory's biogas plant uses wastes from the pulping process and provides 15 per cent of power requirements. Many Indian companies, among them chocolate manufacturers and distillers, are following suit. An added bonus is that the effluents used to make biogas are broken down in the process, making the resulting waste water easier to treat.

Nick Rance

Biogas is a production of Bernard Lang AG and is available from:

TVE
Distribution Office
Prince Albert Road
London NW1 4RZ
UK
Tel: + 44 (0)171 586 5526
Fax: + 44 (0)171 586 4866
Email: tve-dist@tve.org.uk
To order on-line, see TVE's
Moving Pictures catalogue at: http://info.tve.org/index.cfm