Our firm, in association with Golder Associates, provided engineering services for the design and implementation of an on-site leachate collection and treatment system. The Environmental Assessment (EA) approval process for the long-term expansion of the landfill at this facility required that leachate impacted groundwater and surface water be collected and treated on-site for discharge to surface water. The design team was responsible for evaluating alternative methods of collection, pumping and treatment, and working with the Ministry of the Environment (MOE) to determine the acceptable performance criteria for the facility. Extensive studies and discussions were undertaken to satisfy Federal Fisheries Act requirements and Provincial Water Quality Objective Policies 1 and 2.
The studies concluded that a vertical flow wetland treatment system was the preferred option to treat leachate impacted groundwater and surface water. An agreement was also reached with a local sewage treatment plant to receive leachate as an emergency contingency measure. On this basis, the site expansion EA received approval from the MOE.
The on-site treatment system is rated for 135 m3/day, and consists of a surface water interceptor and gravity sewer, a groundwater interceptor trench, mechanical pumping station and forcemain, equalization pond, and a four-cell engineered wetland, discharging just downstream of the surface water interceptor. In addition to completing design services, the team provided construction contract administration and developed a long-term monitoring program for the on-site leachate treatment facility.