The existing Petrolia Wastewater Treatment Plant was deteriorating after 40 years of operation. The Town of Petrolia, a central community of 5,500 in the County of Lambton, selected CIMA+ to provide an innovative approach to upgrade and retrofit the existing plant as well as treat the Town’s current and predicted 25-year flows with an expanded plant capacity. The new plant reduces the Town’s emergency wastewater expenditures and supports Petrolia’s community growth development plan. Due to the need to ensure continuous operations of the facility, the upgraded plant was designed on the existing site next to the old treatment plant. It was built offline from the old plant to minimize disrupting the facility. The plant was upgraded to treat an average daily flow of 5,300 m3/d including leachate from the Petrolia Landfill, and will provide year-round nitrification. This project won the 2018 Small Municipality Public Works Project of the Year Award from the Ontario Public Works Association (OPWA).