The Annacis Island Wastewater Treatment Plant currently serves 1.25 million people in 14 Metro Vancouver municipalities, and once the Stage 5 project is complete, it will serve 1.5 million people. The previous expansion, Stage 4, was done in the late 1990s. The $184 million contract for the outfall pipeline was awarded in September 2019. The outfall pipe will be excavated using a tunnel boring machine. The Annacis Island facility currently treats wastewater using primary and secondary treatment technologies. An expanded facility will ensure that the plant can manage a higher volume of wastewater, continue to keep odour to a minimum and will continue to operate in the event of a major earthquake. There are over 20 projects planned as part of the on-site improvements of the Annacis Island Wastewater Treatment Plant. Improvement projects include: new trickling filters; Secondary clarifiers; and A co-generation facility to make better use of green energy captured on site.