Advisory of the Day
VANCOUVER, BC: IT FLOWS BENEATH YOUR FEET: A LOOK AT THE METRO VANCOUVER WASTEWATER TREATMENT SYSTEM, BC
Wastewater is any water that has been used in some fashion or other. In the Vancouver area 80% of this water comes from homes flowing through drain pipes from sinks, toilets, showers, and dishwashers. The Metro Vancouver area treated 415 billion litres of wastewater in 2015
I spoke with Christianne Wilhemson of the Georgia Strait Alliance a local environmental group engaged in protecting the Georgia Strait and adjoining waters. According to Wilhelmson the efficiency of the Vancouver system is not what it could be, "every day wastewater with a variety of chemicals from different communities" flows into the surrounding waters. Luckily, in Wilhelmson's opinion, this is not a drinking water issue being that most of this used water flows back into the ocean.
Though wastewater treatment may not effect drinking water, it does have an impact on the surrounding water environment. According to Wilhelmson evidence of chemicals can be found in the "sediment [and] shows up in the wildlife. One of the most obviously affected are killer whales that spend part of the year in the area.
I also contacted Fraser Riverkeeper, another local environmental group who has the quality of recreational waters at heart. Joe Daniels, a Coordinator with the organization, states that one the major problem with the wastewater system in Vancouver "is that it's old". The system in the city is a shared system and according to Daniels "storm water and wastewater" flow through the same system.
When there is sewer overflow, the way the systems is designed "water is pumped back out without proper treatment" Daniels said. According to Daniels the city is "on track to meet the 2050 date" to separate the wastewater and storm water systems. The city has also implemented programs to improve the situation such as free pumping for boaters so they don't have to dump sewage into the river" Daniels said. As a result "beaches were open pretty much year round last year".
There are five wastewater treatment plants that are owned and operated by Metro Vancouver. The water flows out of homes and businesses into municipal sewer systems which account for 8500 km of the sewerage system. From there, water is moved through regional trunk sewers and 33 pumping stations to either the Annacis Island, Iona Island, Lions Gate, Lulu Island, or Northwest Langley Wastewater Treatment Plants
With the Operational Certificates issued under the Environmental Management Act by the Ministry of the Environment in 2004 the five plants in the Vancouver area must meet daily compliance levels for Biochemical Oxygen Demand (BOD) and Total Suspended Solids (TSS). Clifford C. Hach, Robert L. Klein Jr., and Charles R. Gibbs describe BOD as "the amount of oxygen, expressed in mg/L or parts per million (ppm), that bacteria take from water when they oxidize organic matter." While Stormwaterx describe TSS as "particulates of varied origin" that are suspended in water
Two of the treatment plants, Lion's Gate and Iona Island, are only primary treatment plants and account for 52% of the flow of effluent. Primary treatment is essentially leaving wastewater in large tanks so heavy solids will sink to the bottom and lighter solids rise to the top. Once this matter has been removed, the water is discharged into the ocean
The remaining three plants, Annacis Island, Lulu Island, and Northwest Langley offer the more effective secondary treatment. Secondary involves the use of chemicals to further breakdown solids in the effluent before being pumped into the lower end of the Fraser River. Planned construction on a $700 million upgrade of the Lion's Gate treatment plant to a secondary facility is set to begin in spring 2017.
Join me tomorrow as we continue to wade through the turbidity of water issues in Vancouver.
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