Wessex Water Plc is finding value in the toilet.

The water and sewage-treatment firm in southwest England has begun testing a Volkswagen Beetle powered by biogas from human waste.

"We plan to see how economical and environmentally beneficial the car is after a six-month trial," company spokesman Ian Drury said. "If successful, we may look to power some of our fleet on biogas."

The company’s GENeco unit is converting gas from a Bristol treatment plant into bio-methane. Greenfuel Co., located in nearby Bath, modified the car to run off the biogas.

If all the biogas produced by GENeco was channeled into use in vehicles, it could power 5,694 vehicles, based on an annual mileage of 10,000 miles, Drury said Tuesday in an e-mail. This would offset some 19,000 tons of carbon dioxide that would be released by the vehicles using conventional fuels. Waste flushed down the toilets of about 70 homes in Bristol is sufficient to power the so-called "Bio-Bug" for a year, based on an annual mileage of 10,000 miles, Bath-based Wessex Water said in a statement.