Operational Biocover Feasibility Study for Small Landfills

The Regional District of Mount Waddington (RDMW) will perform an operational study on one of its capped landfills that may change the way in which the municipality, as well as the province, approaches landfill gas management. This two year study will provide an opportunity to monitor and confirm the effectiveness of a natural methane mitigation approach by designing and applying a biocover soon after an engineered lined cell is closed, and then tracking the reduction in methane emissions from the peak of the gas generation curve, when gas generation rates are the highest. Conventional practice for closure of landfills involves sealing the contents of the landfill in an impermeable barrier that prevents moisture from entering and prevents landfill gas from escaping, adding further expense in dealing with gas distribution and capture/flaring systems. In contrast, the RDMW’s experience to date with promoting decomposition of organic matter and naturally oxidizing methane emissions from the landfill by using a biocover fabricated from waste material actually reduces operating costs and has the promise of also reducing long term capital costs by eliminating the need for a final impermeable cover. The district will couple a landfill biocover system to an existing landfill leachate treatment system to ensure that leachate generated from the landfill and the composting operation is also contained and treated. To improve the understanding of landfill gas generation and biocover effectiveness, improved monitoring instruments will be installed including landfill temperature sensors, flowmeters for leachate and an improved weather station at the site. Landfill gas measurements will be taken three times a year. In addition to the project period reduction in greenhouse gas emissions estimated at more than 3,000 tonnes CO2e, the proposed project study will provide data that could be utilized by any landfills that share some of the characteristics noted here. The study will also help improve techniques to improve the efficiency of the biocover system in removing landfill gas as well as controlling erosion and helping reduce the toxicity of leachate. The potential operational change in LFG management could not only have an impact at the municipal level, but results will also be presented to promote similar changes to current provincial regulations on landfill gas management.