Wastewater & sewer
The purpose of our wastewater treatment is to protect Okanagan Lake and the connected waterways. If wastewater is not treated, it would flow directly into our freshwater sources - where we get our drinking water from. This would threaten public health, fisheries, wildlife habitat, tourism and recreation opportunities.
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 to accommodate our city's growth.
Residential wastewater is mostly made up 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 which 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.
See the wastewater Source Control page for information about restaurant waste, liquid waste disposal regulations, hazardous waste disposal, waste discharge permits and other source control initiatives.
Please note, the Wastewater Treatment Facility does not provide a sanitary disposal facility for recreational vehicles.
In 2011, the City completed its largest infrastructure project to date, the expansion of the Wastewater Treatment Facility. With this project, the facility has been able to increase its capacity to treat water from 40 to 70 million litres a day. This will accommodate the City’s sewer servicing needs beyond 2030.
As part of the expansion, new equipment was installed that increase the facility’s energy efficiency and reduce the use of potable water. Innovative technologies include UV disinfection of the effluent which is used to inactivate bacteria with no residual effect and a state-of-the-art odour control system which will benefit the environment and surrounding area. The expanded Wastewater Treatment Facility 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.
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 480Km 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 called a Parshall Flume, which monitors actual flow to the plant.
The sewage then flows to the primary clarifiers. Primary clarifiers are tanks 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 disposal 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, nitrogen and other contaminants. In simple terms, incoming effluent (a carbon source) becomes food for the bacterial organisms (sludge) which live in the big concrete tanks. During the process, phosphorus is absorbed and trapped in the bacterial cells. These settle out later as solids (sludge), which are dewatered to a 20 % 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 pumped back to the Bardenpho reactor.
Effluent is then directed to the filtration building where the remaining fine solids are filtered out through cloth disc filters. Effluent is then disinfected using ultraviolet light before it flows into Okanagan Lake through an outfall pipe that is 1.2Km off shore and more than 60m deep.