Wastewater Treatment Facility

Our Wastewater Treatment Facility (WWTF), serves approximately 80 per cent of Kelowna’s population (including residents, businesses and industries), and is being expanded to reach unserviced areas and accommodate our city's growth.

Our wastewater treatment process protects Okanagan Lake and the connected waterways. Untreated wastewater would flow directly into the freshwater source that supplies our drinking water; this would threaten public health, fisheries, wildlife habitat, tourism and recreation opportunities.

Residential wastewater mainly consists of water from our toilets, showers, sinks and laundry machines. However, not all waste can be treated by this system. Some businesses and industries produce waste that may contain hazardous materials and should be disposed of through a qualified collection service. Food service establishments (such as restaurants, cafés, butchers, supermarkets, etc.) produce waste that may contain fats, oils, grease and food scraps, which cause sewer blockages when put down the drain. 

The Wastewater Source Control Program section on this page contains information about restaurant waste, liquid waste disposal regulations, hazardous waste disposal, waste discharge permits and other source control initiatives. 

Please note, the WWTF doesn’t provide a sanitary disposal facility for recreational vehicles.

    Wastewater Treatment Facility - built for a sustainable future

    In 2011, we completed our largest infrastructure project to date: the expansion of the WWTF. The expansion increased the facility’s capacity to treat wastewater from 40 to 70 million litres a day. This will accommodate our sewer servicing needs beyond 2030.

    New equipment was installed as part of the expansion that increased the facility’s energy efficiency and reduced the use of potable water. Innovative technologies include UV disinfection of the effluent, which is used to inactivate bacteria and a state-of-the-art odour control system that benefits the environment and surrounding area.

    The expanded WWTF uses the latest technology for the biological treatment of sewage. The newly constructed maintenance building was built to LEED Gold Standards and includes innovative technologies to reduce energy and GHG emissions, conserve water and create a healthy work environment. Materials used in the construction of the new building were made locally with recycled content where possible, and 75 per cent of waste was diverted from the landfill.

    Bardenpho Wastewater Treatment Plant

    The Bardenpho Wastewater Treatment Facility replaced the original Wastewater Treatment Plant that was built in the early 1900's. The Bardenpho upgrade was completed in the spring of 1982. The facility was the first of its kind built in North America to accommodate the Bardenpho Process for biological nutrient removal. The chemical-free process is effective, cost efficient and environmentally sound.

    How it works

    More than 480 kilometres of sewer mains collect and convey sewage to more than 30 pump stations, which pump the sewage to the treatment facility on Raymer Avenue.

    Incoming sewage enters at the headworks in the northeast corner of the plant site. Pumping is necessary at the front end to provide gravity flow through the remainder of the plant. The headworks consists of travelling screens (machines designed to shred rags and other large solids), grit chambers (to settle out coarse grit material) and a flow measuring device.

    The sewage then flows to the primary clarifiers : where the large organic solids are allowed to settle out. A mechanical scraper continuously removes the settled solids from the bottom of the tanks to a hopper at one end, where they are drawn off to the fermenter/thickener and then pumped to dewatering facilities. 

    Overflow from the primary clarifiers goes to the biological reactor, where the liquid passes through a series of anaerobic (without oxygen), aerobic and anoxic zones to remove phosphorus and nitrogen. In simple terms, incoming waste (a carbon source) becomes food for the bacterial organisms (sludge) in the biological reactor. During the process, phosphorus is absorbed and trapped in the bacterial cells. The bacteria settles out later as solids (sludge), which are dewatered to a 20 per cent solid solution before being taken to the City's composting facilities.

    After leaving the Bardenpho reactor, effluent flows to secondary clarifiers. Most of the remaining solids settle out in these tanks and are scraped from the sloping bottoms to a central sump, where they are recycled back to the Bardenpho reactor. 

    Effluent is then directed to the filtration building, where the remaining fine solids are removed through cloth disc filters. Effluent is then disinfected using ultraviolet light before it flows into Okanagan Lake through an outfall pipe that’s 1.2 km off shore and more than 60 metres deep.

    Wastewater Source Control Program

    Our Wastewater Source Control Program is a pollution prevention strategy that aims to protect our environment and watershed by reducing industrial, business, institutional and household chemicals from being discharged to the city sewer system and eventually back into Okanagan Lake.

    Since Okanagan Lake supplies drinking water to more than 60,000 residents in the Kelowna area, it’s important to keep specific chemicals out of our precious water supply. Some chemicals, drugs, and pharmaceuticals can’t be treated or removed at our Wastewater Treatment Facility (WWTF) and may affect treatment processes.

    What can't go down the drain?

    The Sanitary Sewer Storm Drain Regulation Bylaw details the specific wastes that are prohibited from being discharged to the sewer. Hazardous waste should never be disposed of down the drain. You can find further information on recycling and disposal options for a variety of hazardous wastes on the websites of the Regional District of Central Okanagan and Recycling Council of BC.

    The BC Medications Return Program provides detailed information on where to properly dispose of unused pharmaceuticals and medications.

    Did you know?

    • Some drugs and pharmaceuticals can’t be treated or removed at the WWTF and should never be flushed down the drain or toilet
    • Cooking oil and grease are the major causes of sewer blockages in Kelowna; it costs more than $60,000 annually to clear these blockages in our sewers
    Information for residents

    Videos are courtesy of our partners at RDCO