Water Pollution Control Plant
The WPCP was first constructed in 1962 and consisted of a pumping station and a waste stabilization pond. From then the WPCP has undergone modifications in 1970, 1982, 1997, 1999, 2001 and most recently 2009, and again the WPCP is expected to begin upgrades in 2020.
Currently the WPCP is classified as a Class 4 treatment facility and a Class 3 Collection system. The collection system collects and transports sewage from all residential, industrial, commercial and institutional facilities connected to the municipal sewer system to the WPCP for treatment. The collection system consists of gravity sewers, forcemains and pumping stations. Pumping stations convey sewage to provide hydraulic lift to ensure sufficient flow to the WPCP.
The BWG collection system and WPCP are monitored continually and operated within compliance of all applicable legislation. All BWG staff that operate the collection system and WPCP are licensed to do so and are required to follow all regulatory requirements and applications.
The WPCP process consists of three main stages, beginning with primary treatment. Once the wastewater reaches the WPCP it enters the Headworks Building where all large debris and grit are removed and disposed of. The wastewater initially passes through bar screens which only allow small debris and wastewater to pass, large debris are then trapped and removed frequently. This prevents any damage to the treatment system and equipment, debris in wastewater consist of toilet paper, and non-biodegradable objects. The wastewater and grit that passes through the bar screens travel to the grit vortex where the heavier solids settle to the bottom and allow the wastewater to pass through to secondary treatment.
Secondary treatment begins with the aeration tanks. Air is injected to the wastewater and monitored by Dissolved Oxygen probes to ensure adequate aeration to facilitate microorganism growth to breakdown the organic matter. During the addition of the air the wastewater is continually in motion to ensure the microorganisms have continual contact with the organic matter. Microorganisms feed on the organic matter, and create flocs which settle out. Aluminum sulphate is added to achieve optimal coagulation of the flocs and to ensure the settling ability of the wastewater is sufficient. The wastewater is than feed into the clarifier tank to settle out the microorganisms and floc. The microorganisms settle to the bottom of the tank and are feed back into the aeration tank to continue to breakdown organics in the wastewater, this is referred to as Return Activated Sludge (RAS).
After the RAS has settled out of the effluent, the effluent than continues to tertiary treatment. The effluent passes through deep bed sand filters which help purify the effluent removing remaining suspended solids and reducing biological oxygen demand.
During disinfection the wastewater flows through sets of ultraviolet light (UV) banks, which provided final disinfection for the wastewater effluent. The UV disinfection inactivates all pathogens and bacteria which remain in the wastewater effluent prior to UV disinfection. The effluent that is deposited after UV disinfection is required to meet the standards set out by the provincial and federal government. The effluent is monitored by wastewater staff to ensure the West Holland River receives only water that has been treated to entirety of the plants capability, and will not impact the environment or human health.
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1. It starts at the source
Wastewater from toilets, sinks, showers, laundry and all other drains in homes, business, schools and industrial facilities flows into the municipal sewer system, which carries the wastewater through the sanitary sewer system to the Water Pollution Control Plant (WPCP).
2. Remove debris
The first step at the WPCP is to remove the inorganic material. Wastewater passes through bar screens that filter out large debris. Next, it goes through a “grit vortex” where swirling water causes smaller debris to settle to the bottom.
3. Remove organic matter
Wastewater is fed into aeration tanks, where microorganisms consume organic matter. The air in the tanks is continually monitored to ensure ideal conditions for the microorganisms.
4. Remove microorganisms
Once the microorganisms cannot digest any more organic matter, the wastewater goes into a clarifier. Here, microorganisms and other particles settle into a sludge. The sludge is returned to the aeration tank where air reactivates the microorganisms so they can be put back to work.
The final step in treatment is disinfection. The wastewater passes through sand filters, which remove any remaining particles of organic and inorganic matter.
6. More disinfecting
Afterwards ultraviolet light is used to kill any remaining bacteria, viruses and other disease-causing microorganisms.
7. Return to nature
Once it has met all regulatory requirements, the treated water is deposited into the West Holland River.