As the second largest secondary treatment facility in Canada, Metro Vancouver Regional District’s Annacis Island Wastewater Treatment Plant (MV AIWWTP) in Delta, B.C., presently serves about 1.3 million people in 14 member municipalities in the Fraser Sewerage Area (FSA).
The pumping facility at the Annacis Island plant is a critical part of the infrastructure, as collection and conveyance systems transport the FSA wastewater to the plant. The three 1,200-horsepower influent pumps and four 684-horsepower trickling filter pumps have been in service for about two decades and were at their end-of-life stage. These large pumps regulate the level of raw sewage in the wet well, conveying it into the treatment plant. Should these fail during high flow situations, there are overflow gates, but these bypass raw wastewater into the Fraser River, which would lead to consequential fines and penalties due to its environmental impact. The trickling filter pumps power the flow of the partially treated waste over trickling filters for secondary treatment, which capture most of the bacteria before the final purification processes.