Wastewater Treatment

Treatment Processes

• Sewer Main Flushing

  Please be aware that flushing is done on a regular basis to help clean and remove debris from the mains. High-powered jets of water are blasted through the pipes to clear grease, dirt and sediment and ensure they are flowing well.

  This process can cause minor annoyances to private properties. It may also cause your toilet to burble or splash. If you have any questions about the flushing process, please contact Public Works.

• Virtual Tour: Created by Todd Redding, Okanagan College

How it All Works

• About the Wastewater Treatment Process

  Here’s a play-by-play of the wastewater treatment process. Our brochure explains these processes.

  Step 1: Headworks. Incoming wastewater travels through fine screens, where most of the unflushables are removed. These solids are washed, conveyed to a bagged garbage bin and taken to the landfill. The influent then flows through a degrit system where heavier solids are further separated out.

  Step 2: Primary clarification. Wastewater then flows by gravity to one of two primary clarifiers. At this stage, collectors skim the tank and remove the settled solids. Flow exits the tanks and continues to the splitter box, where it is split into the two bioreactors.

  Step 3: Bioreactors. The liquid passes through three zones in a process that removes phosphorous and nitrogen. This includes the anaerobic (without oxygen), anoxic and aerobic (with oxygen) zones. The different environments encourage bacteria and other microorganisms to feed on different components of the wastewater.  

  Step 4: Secondary clarification. The bio-reactor effluent flow moves to the two secondary clarifiers and the settled sludge is returned to bioreactors. Any floatables are skimmed and pumped to the Dissolved Air Floatation (DAF) tank for further processing. The effluent then then flows to the filters.

  Step 5: Filters. The secondary clarifier effluent is filtered to remove particulate.

  Step 6: Disinfection. Effluent is disinfected by ultraviolet light, which inactivates microorganisms.

  Step 7: Effluent reuse. Reclaimed water is used to irrigate City parks, sports fields, school grounds and the Penticton Golf and Country Club. All reclaimed water is chlorinated before leaving the wastewater treatment plant and is tested during the irrigation season daily for E. coli and chlorine.

  The Okanagan College and Treatment plant also use the reclaimed water for toilet flushing. In addition to toilet flushing, the treatment plant uses the reclaimed water for all hosing around the plant, and heating and cooling in the administration building.

  The Solids Treatment Process

  Step 8: Fermenter. The fermenter digests heavy organic solids and sludge from the primary clarifiers.  This process is referred to as fermentation and creates Fermented Primary Sludge (FPS) and Volatile Fatty Acids (VFA’s), which are used in the nutrient removal process that occurs in the bioreactor.

  Step 9: Sludge thickening – Dissolved Air Flotation (DAF). Here, sludge is mixed with polymer and microbubbles. Solids attach themselves to the microbubbles and float to the surface, where it is skimmed off and transferred to the Thickened Waste Activated Sludge Storage (TWAS).

  Step 10: TWAS storage. The TWAS tanks are aerated with coarse air that is supplied from the process air blowers. Fermented Primary Sludge is not introduced into TWAS tanks to prevent Phosphorus release.

  Step 11: Centrifuge. The TWAS and FPS are combined just before they enter the centrifuge along with a small amount of polymer. It is then thickened to approximately 18% solids, discharged and pumped into two roll off bins, then transported to the landfill, where it is composted.

  Step 12: Composting. The sludge is combined with wood chips and sawdust, then stacked on aeration pipes to dry. The piles are monitored for metals, coliforms, salmonella, PCB’s, moisture, pH, nitrogen and phosphorous. This product is recycled to City Parks and sold as Class A compost to the public and farmers for agricultural use.

• Septage

  The City entered into a partnership with the Regional District of Okanagan Similkameen (RDOS) in 2008 to build and maintain a septage receiving station. The system incorporates a rock trap and a perforated screen. The screened septage is returned to the plant for further treatment and the screenings are taking to the landfill for disposal.

• Cross Connection Control

  Cross connection devices are used on some properties to ensure water doesn’t backflow into the City’s drinking water supply. Visit our Cross Connection Control page for information about how cross connection occurs, how to control it and guidance on the selection and installation of backflow preventers.

• Asset Management

  An Asset Management Plan was used to develop an inventory of all wastewater assets at the Advanced Wastewater Treatment Plant (AWWTP) and the wastewater lift stations, and included asset estimated service lives.

  Assets near or beyond end of life were classified as requiring replacement, demolition, or to be run to failure. Assets are organized by High Priority Assets, Medium Priority Assets and Low Priority Assets.  This process helps to identify and prioritize future Capital projects.

Annual Report

Have Questions?

• How to Contact Us

  For general inquiries about your water, please fill out our Report an Issue online form. We’ll be in touch shortly.

  If you are experiencing an urgent sewer problem or have questions about the sewer system, please contact:

  Public Works
  Phone: 250-490-2500
  Email: publicworks@penticton.ca

  For general information about the City’s wastewater treatment plant, or to book a tour, contact:
  Wastewater Treatment Plant
  Phone: 250-490-2550
  Email: joel.mertz@penticton.ca