'Poo-powered' car seen on the streets of Bristol Published duration 5 August 2010

media caption The BBC's John Maguire is given a tour of the methane-powered car by developer Mohammed Saddiq

A "poo-powered" VW Beetle has taken to the streets of Bristol in an attempt to encourage sustainable motoring.

The Bio-Bug runs on processed methane gas generated as part of the raw sewage treatment process.

Wessex Water engineers estimate the yearly waste from 70 average households would generate enough gas to run the car for 10,000 miles (16,100km).

Despite being powered by fuel created from sewage, the car does not smell unpleasant.

"It performs like a normal car - you wouldn't know it was powered by biogas," a company spokesman said.

'Surplus gas'

To use biogas as vehicle fuel without affecting vehicle performance or reliability the gas needs to be treated to remove the carbon dioxide content.

GENeco, part of Wessex Water, imported specialist "cleaning" equipment to treat the raw methane generated at the sewage treatment works in Avonmouth.

The spokesman added: Our site has been producing biogas for many years which we use to generate electricity to power the site and export to the National Grid.

"With the surplus gas we had available we wanted to put it to good use in a sustainable and efficient way.

"We decided to power a vehicle on the gas offering a sustainable alternative to using fossil fuels which we so heavily rely on in the UK."