Recycling Sewage Fills a Tiny % of Energy Needs

It sounds like a good idea, but it’s a mere drop in the bucket.

A UK sewage and water company, Northumbrian Water, has been recycling its sewage for the last six years, producing enough gas and electricity to power 7,000 homes. And while that sounds impressive, it’s an infinitesimal blip for the United Kingdom’s total energy demand.

While Global Water Intelligence notes that water and wastewater utilities are energy hogs, devouring 3.7% of the world’s annual energy, all the UK’s sludge – if recycled – would only fill 1% of their total energy needs. So that’s discouraging.

Also, it’s pricy and isn’t exactly repeatable worldwide.

“Most low- and middle-income countries can’t afford to treat wastewater despite its impact on the environment and public health,” said Christopher Gasson, chief executive of GWI.

The opportunities are there – apparently, every person produces around 30g to 80g of useful dried material a day (I’ll leave it to your imagination as to what that material is) – and while 17 large water and sewerage companies in the UK have biomethane production somewhere in the range of 477GW-hours, it’s not nearly sufficient.

And it’s not even like “anaerobic digestion” is a new phenomenon – a version has existed since Victorian times – but it just isn’t to the point where it can make a solid dent in our energy needs.

Partially due to a lack of care.

“Sludge and waste just aren’t being valued sufficiently so there’s room for a lot of expansion,” says Bill Barber, technical director at Cambi. “The world’s population is increasing so there is simply more sludge to deal with.”

But as always, technologies and processes are improving, so perhaps in the future, the share of energy attributed to biogas and bioelectricity could increase, and in the least, we could cut down on the waste that’s…wasted.