A British town uses dog excrement to power streetlights!

Posted on 03 January 2019.

Lighting the town's streets by converting dog excrement into biogas is the 100% local and circular idea that is causing a buzz about a small town located in the West of England.

Dog owners use a lever to drop dog excrement into a sealed tank, which is an anaerobic digester about the size of a washing machine.

It is already known that elephant dung can be recycled to make paper. But what about  the twenty tons of dog excrement deposited on the pavements of our cities every year? In the West of England, Brian Harper has a solution. This ingenious retiree has developed a 100% circular solution to recover this waste in his town of Malvern (population approx. 30 000): he uses dog excrement to produce biogas, which is an energy that can power the town's streetlights.

Anaerobic digestion of waste, especially animal excrement, is not new, but the peculiarity of Brian Harper's solution lies in its local scale: everything happens on the streets of Malvern.

Since November 2017, residents of this Worcestershire town are invited to drop bags of dog excrement down a hatch at the bottom of the town's streetlights. All they need to do is pull a level to lower the package into a sealed tank about the size of a washing machine which is an anaerobic digester (also called a methanizer).

Through the oxygen-free decomposition process in this tank, the excrements generate biogas composed of 60% methane. The digester is directly connected to streetlights to power them with the methane produced and light up at dusk.


Ecological and economical public lighting

The initiative is already a success. Ten small bags of excrement are enough to supply the streetlights with enough energy for two hours of lighting every evening, significantly reducing the town's gas costs. The town estimates that the streetlights will consume 70% less gas by the end of 2018.

Brian Harper's solution is not just of benefit to the town. Neighboring farmers recover the digestate (the solid organic matter left in the tank after decomposition) which is an excellent fertilizer!