Sewers Hold Waste Heat Ready For Recovery

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Harvesting waste heat has grown in popularity in various parts of the world, but most of that comes from air heating, or heat released from machinery of various kinds. International Wastewater Systems of British Columbia has figured out another good source of heat that can be captured: sewer water.

We published one of their videos a few days ago at sustainablog; take a look at that post below, and then let us know what you think.

Waste Heat Recovery… From The Sewer? Canadian Firm Harvests Wasted Hot Water [Video]

We’ve discussed all sort of energy harvesting possibilities from sewage, but nearly all of those were tied to the waste material floating in that water. It turns out the water itself is also a carrier of energy, in the form of heat. British Columbia-based International Wastewater Systems has figured out a technology for waste heat recovery from sewers that can save municipalities and other setting with lots of people quite a bit of money on their energy spending… and make a nice dent in greenhouse gas emissions.

The general premise is pretty simple: we all send hot water – from our showers, dishwashers, sinks, etc – down the drain. That’s energy, and by using a heat exchange-based system they call The Sewage SHARC, IWS provides a means to recover that energy.

The video above goes into much more detail on how this works, including the kinds of cost savings it can produce. Yes, this is a promo video, with lots of promo-speak, but the underlying concept and the technology the company’s built are just fascinating. I know a number of European countries have done great work with waste heat recovery at a municipal scale, but, even in those cases, I’m not sure that heat from the sewers is part of the equation.

This video’s a little longer than what we normally post, but well worth your time. Once you finish it, please share your thoughts with us in the comments.

Featured photo credit: photowind via Shutterstock

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Jeff McIntire-Strasburg

Jeff McIntire-Strasburg is the founder and editor of sustainablog. You can keep up with all of his writing at Facebook, and at

Jeff McIntire-Strasburg has 26 posts and counting. See all posts by Jeff McIntire-Strasburg

10 thoughts on “Sewers Hold Waste Heat Ready For Recovery

  • Most heat you send down the drain with showering can be recovered in your own house. My HR-drainpipe was €400 and recovers 4-10 kW of free power that would otherwise be wasted.

    But for cases where draining hot water and taking in cold water are at different moments, using this resource at municipal level is of course the next best thing 🙂

    • Yes a HR=drainpipe should be mandatory for every new house, every retrofit.
      Have one in my place. 🙂

  • I have not heard of HR-drainpipe. I Googled and and can’t seem to find any information. Is this kind of thing available in the US?

    • What it is; one large copper pipe`wrapped with a smaller copper pipe, small one has cold water going to hot water tank, large one is used grey water.

    • As others explained: a drainpipe that pre-heats cold tap water before it enters the heater.

      My version consists of two concentric copper pipes, the 50mm inner pipe is the drain and the jacket that is formed by the outer and inner pipe contains the tap water to preheat. There is a bit more to it to ensure a double barrier between sewer and tap water, but that’s the basic idea. Just a low-tech vertical counter-flow heat exchanger.

      I’ll add a separate post with some Dutch links in it, with Google Translate I’m sure you can find something similar in the US. The Power-Pipe is already named, from the looks of it, it’s a lot more copper and a lot more expensive.

  • Personally I think IWS has hit the mother lode. Heat from building effluent is constantly available. Easily recovered heat energy with these new SHARC and Piranha systems. Their existing installations have proven the efficiencies and ROI. Every building should have such a system, especially hospitals, prisons, colleges for example. Also I like that the IP is secured by patents or applications. Good luck to them and thanks for helping reduce carbon emissions.

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