You wouldn’t think that human poop has many uses, but it turns out that the UK is using brown to go green. As of today, Britain’s first “poo bus” will be shuttling passengers between the city of Bath and Bristol Airport. And yes, you guessed it: it’s powered by human waste, alongside food waste.
This “Bio-bus” runs on biomethane gas, which is produced from the treatment of human sewage and food that is unsuitable for human consumption. It has a combustion engine that is similar to diesel engines in normal buses, but the gas is stored in dome-like tanks on the roof.
The gas is generated using anaerobic (oxygen hating) bacteria, which break down the waste into methane-rich gas. Before it can be used to power buses, CO2 is removed and propane is added. Other impurities are also removed so that the emissions are virtually odorless (thank goodness). It also produces fewer overall emissions than traditional diesel engines, and is obviously more sustainable.
Just one person’s annual food and sewage waste is enough to fuel the bus for 60 kilometers (37 miles). One tank is sufficient for a 300 kilometer (186 mile) journey, which is about five people’s annual waste.
The company behind the gas, GENco, produces approximately 17 million cubic meters of biomethane annually, which is enough to power around 8,300 homes. And as of this week, they’ve started injecting gas generated from human and food waste into the national gas grid network.
“A home generated green gas, biomethane, is capable of replacing around 10% of the UK’s domestic gas needs and is currently the only renewable fuel available for HGVs,” said Charlotte Morton, chief executive of the Anaerobic Digestion and Bioresources Association. “The bus also clearly shows that human poo and our waste food are valuable resources.”
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