The Regional District of Okanagan-Similkameen (RDOS) is actively working on the commissioning of a polishing wetland, using the natural functions of vegetation, soil and organisms to support enhanced wastewater treatment at its Okanagan Falls Wastewater Treatment Plant (WWTP). The polishing wetland project has been a future component in wastewater treatment since the idea was initially discussed during the development of the ‘Okanagan Falls Sewage Treatment Plant – Strategic Review’ in 2005.

Although the WWTP currently discharges high quality (low nutrient, sanitized) effluent to the Okanagan River that consistently exceeds the required targets of the Operation Certificate, the addition of a polishing wetland represents an opportunity for innovation, using natural ecosystem processes and phytoremediation to further improve discharge water prior to introduction to the Okanagan river. In addition to serving a valuable role in wastewater treatment, the wetland also has the potential to act as a research, education and interpretation site.

The primary purpose of the polishing wetland is enhanced treatment. A treatment wetland is a human-made, engineered system that uses wetland elements (i.e., plants, water and soils) to improve water quality. It has the potential to remove contaminants that are beyond the current capability of wastewater treatment plants.

In 2015, the Regional District purchased a property for developing a wetland system. The following figure shows the location of the property in relation to the wastewater treatment plant.

Current site of wetland under construction:

The construction of the polishing wetland was completed by the end of February 2020 and is currently undergoing a commissioning period including plant establishment and operational testing. Initial wetland seeding took place in the spring and summer of 2020, after construction was complete. Commissioning of the polishing wetland necessitates a multi-year period of water level management (during both the growing and dormant seasons’) to encourage wetland plants to grow. The commissioning process began in March 2020 and is estimated to take two to three years to complete.

Funding for the $1.06 million wetland system project comes from two different sources. The project received $361K from the Regionally Significant Projects (UBCM Grant) and $700K from the Area ‘D’ Community Works fund.

Native Plant Solutions, a branch of Ducks Unlimited Canada, designed the wetlands and oversaw the construction and commissioning. Once the wetlands are commissioned there is very little operational effort required to maintain the process, mainly involving opening and closing of the wetlands drain and supply valves for change over from dormant winter period to the active summer period and vice versa.

The Okanagan Falls Wastewater Treatment plant was originally designed to be constructed in multiple phases in order to reduce the initial capital cost of construction. The current phase includes the addition of a solids dewatering process. Currently the thickened ‘cake’ of organic matter is hauled via septic Vacuum trucks 22kms to the Penticton advanced waste water treatment plant for further processing and dewatering before ultimately being trucked to the biosolids composting site on Campbell Mountain Landfill.

Typically, 6 truckloads of sludge are transported each week. With the addition of the solids dewatering process on-site we can reduce the costly shipping process requiring vacuum trucks, instead reducing the requirement to a roll-off truck on a single journey to the biosolids compost facility. The removal of water also greatly reduces the frequency of trucking required as more product can be trucked in a single load.

The new facility is funded by a grant for $2.06 million from the Strategic Priorities Fund administered by the Union of British Columbia Municipalities (UBCM).