A $36.3 million expansion of the biological treatment system is on deck for City of Chilliwack’s wastewater treatment plant.
Council voted Tuesday to approve the design-build proposal from Tritech Group/Stantec Consulting, one of two proponents advanced in the next phase of the request for proposals process at city hall.
Coun. Chris Kloot commented on the huge scale the investment.
“I don’t think we’ve seen such significant investment in our waste water treatment plant,” Kloot said during the council discussion before the vote.
Acknowledging Chilliwack has been “dealing with a lot of growth,” Kloot asked if the expansion prepare the community for next 20 years, and if the city was taking growth on First Nations land into account.
Director of engineering Kara Jefford indicated that the expansion would set the city up for growth, but it’s hard to predict what will happen in communities outside the city boundaries.
The $36.4 million funding for the biological treatment expansion was allocated in the 2024 Financial Plan, and will come out of the city’s sewer fund, sewer development cost charges, as well as government grants, according to city officials.
“Implementation of the project will enhance improvements to the overall effluent quality and further it will result in increased secondary treatment system capacity, reliability and improved operation and maintenance at the City of Chilliwack Wastewater Treatment Plant,” according to the staff report.
Coun. Harv Westeringh asked if the new equipment would help with odour issues at the treatment plant, and was told that not in the purview for this project.
Coun. Jeff Shields asked if the new elements of the treatment system will be built alongside existing ones and if they’ll be decommissioned, and the response was that the expansion will increase capacity, and some of the components will remain in use.
Several components are concrete tanks, with a lifespan of 15 to 20 years, staff said.
In terms of the background context for the expansion, in July 2022 liquid-waste haulers were informed by city officials that Chilliwack would no longer be able to receive septage, or liquid waste, from outside of the City of Chilliwack boundaries.
In July of 2023, city staff began enforcing this directive.
“This action was taken to ensure that the wastewater treatment plant effluent continued to meet requirements,” the report explained.
“The expansion would allow the plant to receive some waste from outside Chilliwack’s boundaries but it is not designed to accommodate all the septage waste that originates in the Fraser Valley Regional District.
“Staff continue to work with FVRD staff as they examine options for addressing the septage waste issue,” the report said.
So how will the biological treatment expansion reduce the “intermittent toxicity” the plant effluent has been challenged with?
To meet effluent quality standards, the treatment plant relies on biological treatment provided by a trickling filter and aerobic bioreactor.
“The trickling filter is at the end of its economical service life having been built in 1992 on a pre-existing foundation built in 1973,” the report noted as background. “The bioreactor was built in 2015 as the first phase of the expansion required to replace the aging trickling filter, to provide capacity for population growth and, to comply with regulatory redundancy requirements,” according to the report.
The report clarified the wastewater treatment plant “plays a key role in protecting public health and the environment and is an important asset that contributes to the city’s overall sustainability goals. The plant serves approximately 75,000 people and receives an average of 23,000 m3/d wastewater from the city’s sanitary sewer system network. In addition, treating the wastewater and discharging treated effluent to the Fraser River, the wastewater treatment plant also generates renewable energy through the anaerobic digestion of wastewater residual solids.
”The Phase 2 upgrade/expansion will be designed to meet provincial and federal effluent conditions.”
Tritech Group Ltd./Stantec Consulting Ltd. was deemed the preferred proponent based on the highest total points.
Anticipated completion date for the $36.4 million project is March 28, 2026.