Tuesday, March 15, 2016

What happens after you flush the toilet?

Well YOU should wash your hands, but where does the wastewater go within Greater Victoria?

Annually, 150 billion liters of raw sewage are flushed into Canadian water ways, from the St. Lawrence River to the Strait of Juan de Fuca and the Pacific Ocean.Source: Environment Canada

Victoria is one of the few remaining Canadian cities that does little to treat its sewage. According to environmentalist, Victoria is one of the worst offenders by pumping roughly 130 million litres of raw sewage directly into the Strait of Juan de Fuca. Source: Globe & Mail

All in all, once you flush a toilet in Greater Victoria, the sewage goes through Source Control treatment stage & Preliminary Treatment stage (only at Clover Point and Macaulay Point). With 344,615 people living in Greater Victoria and an average 5 toilet flushes per person per day... that's a whole lot of poop going into the Strait.

The types of wastewater treatment.

Source Control: focuses on the reduction or elimination of contaminants before they enter the sewer system rather than treating them after they have been mixed with other wastes.

The CRD has been operating a regional source control program since 1994.

Preliminary Treatment: removes sand & gravel and screen out rocks, rags, plastics, etc. which are then sent to the landfill. Wastewater is screened down to six millimeter sized particles then discharged through two deep ocean outfalls into the Juan de Fuca Strait.

Preliminary screening is currently in effect at CRD Clover Point and Macaulay Point pump station.

Primary Treatment: Process where gravity is used to settle solids and grease, oil and fats are skimmed off.

This does not happen within our region.

Secondary Treatment: Removes dissolved oxygen-demanding organic substances using bacteria to convert degradable organic matter into bacterial cells. The wastewater is then filtered by separating treated liquid from grown bacterial cells.

This does not happen within our region.

Tertiary Treatment: Final process to improve wastewater quality. Membrane filter are used for tertiary treatment. Advanced oxidization or UV systems can further reduce levels of pharmaceuticals and chemicals found in wastewater.

This does not happen within our region.

After each level of wastewater treatment, the process improves the quality which will in-return be disposed or re-used. As more processes are used, the cost of building the treatment systems goes up. Meaning, a Tertiary Treatment facility will cost more than a secondary treatment facility (if treating the same amount of wastewater)