NOBODY likes to dwell on what happens after we flush the toilet.

But from this summer, human waste deposited in Didcot loos will end a 23-day-long journey by helping to heat local homes.

The journey is the result of a pioneering British Gas and Thames Water project at Didcot’s sewage works.

The scheme will create enough gas for the national grid to heat 130 houses.

Didcot’s sewage plant currently processes waste from 30,000 homes.

Whatever is flushed away at breakfast time should find its way to the sewage plant by the middle of the day.

Once there, it spends a week passing through three settlement tanks, gradually separating into clear water and gooey muck.

Undegradable solids such as nappies and cotton buds, and even false eyes and teeth, are filtered out to stop them clogging up the sewage system.

The water is gradually cleaned in a variety of tanks until it can be pumped back into the river.

The sludge that has sunk is siphoned off and sent to an anaerobic digester – a turbo-charged composter which heats the waste to break it down and release gallons of valuable methane. The waste decomposes over 18 days, leaving thick, odourless waste, and gas.

The solids are dried out, compressed, and turned into ‘poo-cakes’, similar to peat, to be spread on farmers’ fields as fertiliser.

Since the 1950s, Thames Water has burnt off some of the gas produced, saving the company £15m in fuel bills each year and, at Didcot, it is already used to heat the digesters used to break down the sludge. But from August, the gas will be captured, cleaned, and pumped into the national gas grid.

Project manager Peter Taylor said: “Twenty-three days after you flush your toilet, it could be heating your boiler.

“It makes perfect sense, and the Government is incentivising the use of these renewable resources and putting them into the gas network.

“The locals will get to use the power from their poo. It cannot be put any other way.”

If the experiment works and is replicated across the country, sewage, manufacturing waste and farm slurry could generate 15 per cent of the UK’s gas supplies by 2020.