Biogas from human waste

Householders began cooking and heating their homes with gas derived from raw sewage yesterday, under a £2.5m scheme which is the first of its kind in the country.

The use of human waste to generate "biogas" which can be fed into the national gas grid is part of efforts to reduce harmful greenhouse gas emissions from domestic heating and cooking. It is hoped that the trial scheme at Didcot sewage works in Oxfordshire will produce enough renewable gas to supply up to 200 properties.

The process sees sewage arriving at the works for treatment before the sludge – the solid parts of the waste – is treated using a process called anaerobic digestion, in which bacteria break down the biodegradable material to create gas. The gas is then cleaned before being fed into the gas grid.

The process takes about 20 days from a toilet being flushed to the gas being piped back into people's homes.

It is hoped the project will be the first of many to create heat from waste such as sewage, as Britain tries to hit its EU goal of supplying 15 per cent of all energy from renewables by 2020.