Sewage treatment

While most rainwater is drained directly to the waters that surround Vancouver, our sewage is sent to a treatment plant. 95 per cent of all Vancouver's sewage is treated at the Iona Wastewater Treatment Plant. This facility is owned and operated by Metro Vancouver. Vancouver pays levies to cover the cost of using the plant based on volume. The lower the volume going to the treatment plant, the lower the fees we pay.

Primary treatment

Primary treatment is a mainly mechanical process that removes between 30 and 40 per cent of BOD (biological oxygen demand) and 50 per cent of the TSS (total suspended solids). Iona Island and Lions Gate Wastewater Treatment Plants both provide primary treatment to the wastewater before the effluent - the remaining water - is released into the surrounding marine environment. 

Secondary treatment

Secondary treatment is a biological process that removes up to 90 per cent of BOD and the TSS. Lulu Island, Annacis Island and Northwest Langley Wastewater Treatment Plants provide secondary treatment to the wastewater before the effluent - the remaining water - is released into the Fraser River. 

The remaining 5 per cent of Vancouver's sewage is treated at the Annacis Island Treatement Plant. This plant already offers secondary treatment.

For more on the region's plan for liquid waste management click here