The first Secure Landfill ever to receive approval under the Environmental Assessment Act and constructed in British Columbia was designed, tendered, and construction managed by Associated Engineering, with the assistance of NLR Consulting. The CCS Energy Services Silverberry Facility, where the landfill was constructed, is located north of Fort St. John off of the Alaska Highway.
The landfill is constructed with a multi-layer containment barrier and a leachate collection system. The containment barrier system consisting of two layers of a compacted clay liner separated by a two-sided geocomposite, a 60 millimetre high-density polyethylene liner, a two sided heavy non-woven geotextile layer along the floor of the landfill, and a one sided geocomposite layer along the side slopes.
Drainage gravel, covered with a light non-woven geotextile, on the floor of the landfill allows leachate from the waste fill to drain into perforated pipes lying in collection trenches. The leachate flows along lateral trenches to a perimeter trench, which houses a larger perforated pipe connected to a manhole sump. Once leachate has accumulated in the manhole, it can be removed and taken away for disposal. A subdrain system consisting of perforated pipe surrounded by drainage rock and wrapped in a light, non-woven geotextile runs below the perimeter leachate collection trench and drains into a manhole outside the landfill where the accumulated water can be removed.
Along with being responsible for construction inspection of the landfill, Associated Engineering was also responsible for inspecting upgrades to the existing access road and a fencing contract. Associated Engineering has assisted NLR in the design of an overall development plan of the site for future landfill.