Biogas from Human Waste – The Next Wave of Renewables

As the Chinese population moved from the countryside to towns in search of prosperity a lot of things happened. The demand for energy increased and so too did the amount of human waste. Enter Heinz Peter Mang, a German engineer who connected these two events and came up with biogas.

In 2013, China’s urban population had overtaken its rural population when the former breached the 731 million mark, resulting in urban headcount higher by 100 million, Bloomberg reports.

In Beijing alone, city residents’ excrement treated every day is about 6,800 tons, which is enough to fill three Olympic-size swimming pools. Many of the people coming in from the countryside are unused to lavatories and there has been a big cultural push to have urban dwellers use them correctly. The fecal matter is collected and treated using methods familiar to many farmers who use animal manure to created biogas.

Human waste is collected in trucks, which drive to a depot and channel the human waste through a pipe into a machine, where unrecyclable solid material like tissue paper is separated out.

The rest then goes for separation: the solid waste is propelled into a compost wing to ferment at 140° for 10 days. The process kills harmful bacteria and roundworm eggs and turns the excrement into rich fertilizers for trees and vegetables. The liquid material is routed into tanks to generate biogas, and eventually pumped to bigger water-treatment plants.

Human waste recycling is moving from the Third World into developed economies. The UK operates a smaller version of this scheme, which also operates in African countries and Cuba. It seems that where’s there’s muck there’s money and Credit Suisse estimates this market will grow 200%-400% over the next five years.