Wastewater Treatment Plants and Processes

​​Metro Vancouver treats about 440 billion litres of wastewater (or sewage) every year. Wastewater can contain a number of different pollutants and waste products, including soap, food scraps, human waste, oils and other chemicals.

Wastewater treatment processes​​

Metro Vancouver operates five wastewater treatment plants that process over 1​ billion litres of wastewater (or sewage) every day, protecting public health and the environment.

• Primary treatment (Iona Island and Lions Gate Wastewater Treatment Plants) – removes materials that float or readily settle out by g​ravity, and up to 50% of dissolved organic materials
  
• Secondary treatment (Lulu Island, Annacis Island, and Northwest Langley Wastewater Treatment Plants) – uses biological processes to remove 90% or more of materials, including small suspended solids and soluble organic materials
  

During treatment, wastewater is tested to ensure that treatment plant processes are working effectively and meeting regulations. Treated wastewater (effluent) is rel​eased into the Fraser River, Burrard Inlet or Strait of Georgia. As part of the treatment process Metro Vancouver recovers resources from wastewater, including heat, electricity and biosolids.

Wastewater treatment plant upgrades

Various projects and initiatives are in progress to meet the wastewater treatment needs of our growing region. In addition to building a new North Shore Treatment Plant, some existing plants are being upgraded to improve treatment processes, adapt to climate change, mitigate earthquake impacts, and other needs. Some wastewater treatment plants – like the new North Shore Treatment Plant – will use tertiary treatment processes in the future. Tertiary treatment removes ammonia, nutrients and almost all organic matter.​​​​

Why we treat wastewater

Organic materials in wastewater use oxygen to break down, using up oxygen in the water that fish and other aquatic life need. Biochemical oxygen demand (BOD) is a measure of the oxygen consumed by wastewater. Suspended solids (TSS) in water block light and interfere with the growth of aquatic life. Suspended solids and biochemical oxygen demand are removed during the treatment process.

Treating wastewater removes substances that can harm human health and the environment. Wastewater contains pollutants and waste products, like soap, food scraps, human waste, oils and chemicals. If we don’t remove pollutants from wastewater, they go directly into our rivers and oceans. This can threaten marine life, public health and our ability to swim, boat and fish in our local waters.

Effluent monitoring - operational certificates

Each treatment plant is issued an Operational Certificate by the BC Ministry of Environment. The Operational Certificate requires effluent released from the treatment plant to meet certain treatment standards.

Monthly reporting of effluent quality data is provided for each wastewater treatment plant:

Trucked liquid waste

A small amount of liquid waste is brought to wastewater treatment plants by truck, instead of through the regional sewer system. A summary of trucked liquid waste disposed of at the Iona Island, Annacis Island and Northwest Langley wastewater treatment plants is also provided monthly. ​​