Metro Vancouver is developing a $700 million wastewater treatment plant that will derive energy from sewage. The North Shore Wastewater Treatment Plant (NSWWTP) will be one of the largest heat recovery systems in British Columbia.
The $525-million design-build-finance contract for the NSWWTP was awarded to Acciona Wastewater Solutions LP in April 2017 for Metro Vancouver’s Greater Sewerage and Drainage District (GVS&DD). An estimated $16.9 million will be added to include the option for the heat recovery system. Part of the construction cost, including provincial and federal grants for the heat recovery plant, worth an estimated $6.9 million, will be funded by the GVS&DD. The Lonsdale Energy Corporation (LEC) will handle the construction costs of installing a kilometre of heat distribution piping that will transfer the heat from the plant to LEC’s district energy system which is estimated to cost around $3.5 million. LEC will also cover all future operating and maintenance costs of the heat recovery system.
The facility’s initial design specified that it would collect five megawatts of heat from a portion of the wastewater treatment plant’s effluent for the Lonsdale Energy Corporation.
Lillian Zaremba of the Metro Vancouver Utility Research and Innovations department says that, “It has always been our intent to use our wastewater resources as much as possible.” Metro Vancouver is developing this facility in line with its mandate to become carbon neutral. At the heart of the heat recovery system is a heat pump that Zaremba describes as “the size of a school bus.” Once implemented however, the plant will displace the need for fossil fuels for producing heat. It will generate 75 per cent fewer greenhouse gas emissions than the existing treatment plant with the heat recovery system predicted to reduce GHG emissions by 7,200 tonnes per year.
The systems derives energy from sewage by collecting heat from treated wastewater which averages 15 degrees C. “We run it through the heat pump and it transfers it from one unit to another (the LEC system),” Zaremba said. The condensed heat from the pump then raises the water temperature to up to 82 degrees C. The hot water produced is then used to heat buildings and the spent hot water returns to the heat pump at an average temperature of 50 degrees C. It is reheated again to a higher temperature before looping it around once more through the LEC system.
“For every unit of electricity used (to run the pump), it can generate three units of heat. It is very efficient,” Zaremba said.
There is a potential to generate 25 megawatts of heat from the effluent through this system with the LEC only utilizing five megawatts. Zaremba explains that as the treated effluent is directed back to the Lions Gate Wastewater Treatment Plant outfall pipe, there is the future possibility of recovering heat along that route.
A new pipeline will be constructed to take untreated effluent to the NSWWTP from the site of the old Lions Gate facility and another line to return the treated effluents, with 95 per cent of the bacteria removed. This project was designed to bring Metro Vancouver into a green and sustainable future by generating energy from sewage treatment.
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