Tapping Sewage for Clean Energy is the Ultimate Circular-economy Play

A 130-foot borehole across from Toronto Western Hospital. The Noventa Energy project will help replace 90% of the natural gas the hospital uses to run its boilers and chillers

“This is all in the public right of way, all on Toronto Transportation [Services] land,” says engineer Cam Quinn, a senior project manager at Noventa Energy Partners, matter-of-factly. He peers into the pit and explains that the really tricky obstacles turned up well below ground: old pipes and something he calls “a vortex chamber, a concrete vault, built like a bank vault in the 1970s. We had to do a targeted demolition.” 

None of this civil engineering, however, holds a candle to the most sensitive part of the project, which will happen later this fall, when Quinn’s team bores a few holes into the 10-foot-wide sewer main that traverses the shaft, shunting millions of litres of raw sewage toward the city’s treatment plant. For all the obvious reasons, the city’s water and wastewater officials prefer that its sewer mains aren’t perforated, but this delicate exercise in municipal laparoscopy represents a critical step in one of North America’s most ambitious renewable-energy ventures.