Every time you flush the toilet, take a shower or wash the dishes, you send wastewater down the drain to an underground network of pipes. These pipes, through a series of pumping lift stations, carry the wastewater to the Wastewater Treatment Plant located on Whiteswan Drive. The raw sewage that arrives at the Plant goes through an extensive treatment process to ensure that when it re-enters the South Saskatchewan River, it is safe for people living downstream and for the environment.

STEP ONE - The first step for the raw sewage when it reaches the Wastewater Treatment Plant is the removal of heavy particles from the liquid. This happens in the Grit and Screen Building. Here, the sewage passes through a screen system to remove any material greater that 12.5 mm in size.    This material is removed and transported to the landfill.  The wastewater then passes through a centrifical grit removal system. 

STEP TWO - The wastewater then travels to the Primary Sedimentation Basins where its speed is reduced even further. This allows fine particles to settle. The settling process divides the materials into settled material at the bottom of the basins, called sludge, and wastewater.

The sludge is moved to hoppers at the ends of the tanks by scrapers and is sent to the Fermenters (large, closed tanks with mixing mechanisms). Here, Volatile Fatty Acids (VFAs) are created through fermentation (a chemical process that breaks down organic matter). These VFAs are then used in the next stage of treatment.  Small amounts of fermenter sludge is periodically wasted to the Digesters to ensure the continued success of the fermentation process.

As the wastewater leaves these basins, any floating grease or scum is skimmed from its surface and sent to the Digesters. The wastewater, now called primary effluent, is pumped to the Bioreactors.

STEP THREE - The bioreactors are a state-of-the-art Biological Nutrient Removal (BNR) facility. The wastewater is treated by using micro-organisms instead of traditional chemical methods to break down the unsettled particles and nutrients. The micro-organisms do this by using the nutrients in the wastewater as a food source. VFAs created by the fermenters are used in this process by some of the micro-organisms. The process of BNR is environmentally friendly and helps ensure a cleaner, more natural final product.

STEP FOUR - After nine hours in the Bioreactors, the effluent flows by gravity to the Secondary Clarifiers. Here the micro-organisms in the wastewater settle to the bottom and are returned to the Bioreactors.

STEP FIVE - The clear effluent from the Secondary Clarifiers flows through the UV Disinfection system. Finally the treated effluent flows over a weir and into the South Saskatchewan River.

STEP SIX - The sludge and/or scum removed from the Primary Sedimentation Basins, Fermenters and Secondary Clarifiers will remain in the Digester at 35 degrees Celsius for approximately 20 days. Because there is no oxygen present in the Digesters, it is an anaerobic process and the bacteria begin to produce methane as they break down the sludge. The methane is used as a fuel for the boilers in the Heating Building that heat the Wastewater Treatment Plant.

STEP SEVEN - Stabilized sludge, the end product from the digestion process, is pumped 12 kilometres north of the Plant and is stored in deep ponds. Twice a year the sludge is pumped out and spread on farmers' fields by a process called liquid injection. The sludge is an excellent soil conditioner adding nutrients and moisture.

Highly trained Plant operators in the control room closely monitor all aspects of the Wastewater Treatment Plant, twenty-four hours a day, seven days a week. The on-site laboratory continuously tests the processes to ensure that the water going back into the river meets or exceeds environmental criteria.