Metro Vancouver has received a recommendation to establish a drying facility for biosolids.
Biosolids are nutrient-rich treated sewage sludge that comes mostly from human waste.
According to a report by Lillian Zaremba, a manager with the regional district’s liquid waste services, dried biosolids can be used to replace coal that fuels cement kilns.
The new product can also be utilized in blended fertilizer.
“A recent market analysis anticipates that local cement kilns or the fertilizer market could each use the entire quantity of dried biosolids produced by a facility with capacity of 75,000 bulk tonnes per year,” Zaremba wrote in her report to the district’s liquid waste committee.
According to Zaremba, replacing coal with dried biosolid fuel has the added benefit of reducing greenhouse gas emissions.
The region’s generation of biosolids is expected to increase in the coming years.
This is due to population growth, and upgrades to the district’s five wastewater treatment plans.
Zaremba noted that Metro Vancouver produces 55,000 bulk tonnes of biosolids every year from its wastewater treatment plants (WWTPs).
Zaremba related that 98 percent of these biosolids are used as soil topping.
According to her, the region’s production of biosolids is expected to increase to over 90,000 tonnes per year by 2021.
The volume is projected to grow to over 150,000 tonnes per year by 2050.
“It is unlikely that Metro Vancouver can secure sufficient new land application projects to beneficially use the entire additional biosolids recovered,” Zaremba stated. “Land application projects are vulnerable to fluctuations in customer markets and public concern.”
There’s also no available space to stockpile biosolids, “so excess biosolids that cannot be beneficially used would be sent to landfill disposal”.
According to Zaremba, “available landfill disposal options are located outside of the province”, and do not support the region’s objectives of recovering energy and nutrients from biosolids.
The drying facility is projected to have a capital cost of $197 million.
If Metro Vancouver decides to build one, the facility will be located at one of its wastewater treatment plants.