Typically, when we think of the sewage wastewater that runs under our cities (if we think about it at all), we tend to think of it as a problem. From "fatbergs" and grease clogs to major sewage disasters, there's definitely a case to be made for the idea that our wastewater treatment infrastructure is very far from optimal.

In Richmond, British Columbia, however, some city managers and an enterprising energy efficiency company believe they may have turned a problem into a solution. They are using sewage wastewater, which just happens to sit at a relatively constant 21 degrees Celsius, as a convenient source of heating and cooling for municipal buildings.

At the city's gateway theater, for example, a system has been installed which pumps the aforementioned wastewater from the surrounding neighborhood up and out of the sewer at about 200 gallons per minute, through a macerator which shreds and separates solids from water, returns the solids to the sewer and then uses the clean water as a source of constant heat for 40 heat pumps which provide about 150 tons of heating and cooling for the building.

According to Ross Burton, COO of International Wastewater Systems, they've been able to actually turn off the boiler and cooling tower and replace it with this innovative, energy efficient system.

sewage waste water recovery system photo An International Wastewater Systems technician checks the installation of a sewage water heat recovery system on an apartment building. (Photo: International Wastewater Systems)

Similarly, the company has installed another system In a 172-unit condominium complex that provides hot water for all of the units — saving the residents about 70 percent on their hot water heating bills and, the company claims, saving an estimated 100 tonnes per year in emissions.

Call me squeamish, but I'd much rather use sewage for heat than for drinking water.