What is Leachate & How is it Managed?
Leachate is a liquid that forms from the percolation of rainwater and groundwater through the landfilled refuse. With the opening of Phase 2 to active landfilling in 1997, the inactive Phase 1 area of the landfill was capped to prevent direct infiltration of rainwater and minimize leachate generation. Leachate generated within Phase 1 drains to one of two leachate lagoons and is also captured through several purge wells located north and south of Phase 1. These purge wells pump leachate from Phase 1 to the leachate collection system.
The active, Phase 2 area, was designed to effectively capture leachate by using gravel rather than clay for cover to promote drainage through the refuse and by construction of an underdrain system to collect leachate and discharge the leachate to one of two leachate storage lagoons.
Leachate is discharged from the site via a pipeline to the sanitary sewer. The leachate discharges are regulated by a CRD Source Control Waste Discharge Permit and must comply with the CRD Sewer Use Bylaw 2922. The permit requires routine monitoring and reporting to the CRD Source Control Program to ensure permit compliance.
How is Leachate Monitored?
Leachate monitoring is used to determine the volume of leachate discharged and flow rates to the sanitary sewer. The CRD’s SCADA data collection system provides continuous automated monitoring of the volume of leachate discharged. Leachate testing is conducted monthly to characterize the chemical constituents present in the leachate and assess compliance with the CRD Sewer Use Bylaw.