Heat from sewage? TransAqua plans to tap into warm wastewater

·3 min read

A Moncton-area utility plans to use the sewage and wastewater it treats to heat four of its buildings starting in 2021 in an effort to cut its power bill.

TransAqua processes sewage from Moncton, Riverview and Dieppe.

The incoming material from toilets, showers, sinks and washing machines is about 8 C. It's warm enough that TransAqua wants to tap into using a heat recovery system for a heating and cooling system.

The work, expected to cost around $508,000, is anticipated to start in the spring as part of its nearly complete $90.4-million upgrade to comply with federal clean water rules.

Kevin Rice, TransAqua's general manager, said in a recent interview that the new system is expected to reduce the facility's net greenhouse gas emissions by approximately 22 per cent.

"We need to think outside the box and say, how can we reduce our greenhouse gas emissions even more?" Rice said. "So this is something that is significant."

Shane Magee/CBC
Shane Magee/CBC

Part of the facility's existing wastewater treatment process involves blowing warm air into the water in a section of the plant called the bioreactor that helps break down organic material.

That brings its temperature up to about 10 C. It's at that point, when the effluent is already cleaner that what's come into the plant, that the new system would be used.

It would heat and cool a new building for ultraviolet disinfection, a sludge thickening building and a sludge de-watering building.

"So instead of using our expensive air conditioning systems and expensive heat systems, the amount of temperature that's drawn from the wastewater would be able to reduce those costs significantly," Rice said.

The utility worked with NB Power's industrial energy efficiency staff to evaluate the idea.

Marc Belliveau, a spokesperson for NB Power, said it helped cover the cost of a feasibility study by TransAqua.

Rice said the study suggests the utility could save around $33,000 on its annual power costs.

Rice said the cost of the new system would be covered in part through an NB Power energy efficiency program by offsetting TransAqua's power bill over time.

Shane Fowler/CBC
Shane Fowler/CBC

Belliveau said, based on the information submitted by engineering and environmental consulting firm CBCL, the incentive will be approximately $66,000.

As well, if the facility's overall upgrade project comes in under budget, he said the province has already given the OK to use some of the funding for that work to help pay for the new heat recovery system.

Rice said discussions with the Canadian Water and Wastewater Association's energy efficiency committee led him to believe TransAqua will be among the first wastewater utilities in Canada to implement the system.

Robert Haller, executive director of the association, told CBC he's not sure whether TransAqua will be the first in Canada, but it will be one of the first.

"As municipal utilities work toward long term sustainability, it is innovative projects like this that will be an example for all," Haller said in an email.