Approximately 200 households in the town of Didcot, UK now benefit from gas produced out of human waste. Despite being generated at a sewage station, the gas is highly purified and has no odor.
It takes about three weeks, starting from the collected material to the settlement tanks, to produce gas from human waste. The process involves anaerobic bacteria that digest the sewage and generate methane. The gas can then be used either to produce electricity or can purified and delivered to households.
According to the producing company, British Gas, it is most efficient to supply the gas as it is, instead of using it to generate electricity.
The project is worth around $4 million and has been encouraged by government incentives that are meant to stimulate utility companies adopt renewable technologies. The measure comes as an answer to a directive imposed by the EU that stipulates that the UK must ensure at least 15 percent of its energy is from renewable sources by 2020.
An estimated 1.73 million tons of sewage sludge are produced annually in the UK. This amount could supply enough gas for 350,000 households if used according to the technology.
Other projects that aim at producing biomethane have also been announced. Joint venture partners in the Didcot project, British Gas, Scotia Gas Networks, and Thames Water plan to develop such systems in towns across the United Kingdom. One such is project in progress in Manchester, where biomethane could be supplied to 500 households by next year.