Ever noticed how manhole covers never freeze in winter?
They stay warm, thanks to heated wastewater flowing beneath our streets.
Now, imagine your home. Every shower, every bath, every load of laundry.
You heat the water, use it once and dispose of it down the drain.
So linear
We're wasting that heat.
Energy-wise, we’re binning roast dinners for snacks.
Our Victorian forefather, Bazalgette used bricks to construct a combined sewer system that was ahead of its time. This legacy now provides a sprawling network of untapped warmth under our feet.
We’re sitting on a heat mine.
Other countries are ahead
The Netherlands recovers heat from wastewater and integrates it into district heating systems.
Meanwhile, in Kingston-upon-Thames, Thames Water is trialling heat recovery.
16 billion litres of wastewater could warm 1.6 million homes annually. But progress is slow, held back by siloed thinking and uninspiring headlines.
Challenges v opportunities
Combined waste systems can increase flood risks — but they also concentrate resources.
With smarter infrastructure and collaboration among utilities, engineers, and local authorities, we could create district heating networks.
It’s time to apply circular thinking to the heat in our wastewater. It’s time to harness energy where it’s hiding — beneath our feet.
