Blackstock Landfill Reclamation

The Regional Municipality of Durham has seven landfills that pre-date Ministry of Environment and Climate Change (MOECC) requirements for landfill liners and leachate collection. All seven landfills are now closed, but annual site monitoring indicated varying degrees of contamination on local ground and surface water. In order to address these environmental impacts and their inherent liabilities, and in accordance with the Region’s Strategic and Official Plans, a reclamation pilot on the smallest of the sites (Blackstock Landfill, approximately 2 hectares) will help determine whether recycling of buried materials and remediation for future use is a viable alternative to the business-as-usual regrading of old landfills. While both scenarios necessitate annual maintenance and monitoring, it is anticipated that lifecycle costs following pilot implementation will be lowered and temporary in comparison to the perpetual costs associated with a business-as-usual approach which would likely include the need for further capital expenditure. The pilot is expected to transform a long-term liability into land with an associated residual value. Test pits and waste characterization identified glass, various plastics and metals, construction and demolition debris, and large items such as appliances and fencing in the landfill. The pilot will remove these buried materials and separate them for recycling. All remaining non-recyclable landfill “overs” (waste larger than 2 inches in diameter) will go to the Region’s energy from waste plant (i.e. Durham-York Energy Centre - DYEC). The landfill ‘fines’ (waste less than 2 inches in diameter) will contribute to the grading of the site and the restoration of its original contours. As requested by the MOECC, a surface water station will assess the influence on surface water quality in the area. Groundwater monitoring and analysis will occur for biological oxygen demand (BOD), total suspended solids (TSS), nitrate, sulphate, metals, and various other organic and inorganic compounds. Landfill gas emissions are expected to be minimal during excavation due to the age of the waste however a site specific health and safety plan will be developed prior to construction. Minimizing the working face during excavation and covering any exposed waste at the end of each working day will control potential odour impacts from gas emissions, if required a misting system will be provided. Regular surface and groundwater monitoring has been conducted on site since 2000, post-mining monitoring results will be compared to this historical data to determine the net effects of the pilot project. A technical, financial, and environmental life-cycle analysis of the results will form the basis of a report to Council from both the Commissioner of Works and the Finance Department. This pilot will form the basis for future actions at the Region’s six other closed landfill sites, which all together represent an estimated 40-year $11.6 million liability for the Region. The Region estimates the elimination of approximately 367 tonnes CO2e of methane production through this site alone. In addition, the Region will remove approximately 300 m3 of recyclables, 11,880 m3 of landfill “overs” and 17,820 m3 of “fines”. For their part, the “overs” transported from the site to the DYEC will produce approximately 4.6 million kilowatt hours of electricity. The Province of Ontario is littered with small landfills that do not meet the current environmental standards for liners, leachate or landfill gas collection. This pilot is innovative in that the main goal is to remove recyclables and waste from the site completely, rather than gain useable landfill space or further grade the site. It aims to demonstrate the efficacy of landfill mining to remove sources of potential ground and surface water contamination, as well as methane gas generation, and return the land to its original, natural state for future redevelopment as community spaces. (Project description from original funding application)