Landfill Gas Collection and Control Regulation
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Description
As organic matter decomposes in landfills, various gases are produced by microbial processes, including methane and carbon dioxide (CO2). In a typical landfill, approximately 50 per cent of the gas generated is methane, and 50 per cent is CO2. While each of these contributes to climate change, methane is of greater concern as it has a global warming potential 25 times greater than CO2 based on a 100-year time horizon. In 2007, methane released from landfills contributed an estimated 3.6 per cent of Ontario’s CO2 equivalent emissions. By capturing methane, and either faring or burning it to generate electricity, approximately 95 per cent of the gas’s global warming potential is eliminated.
In June 2008, new rules came into force under the Environmental Protection Act (EPA) that will increase the number of Ontario municipal landfills required to have landfill gas collection systems in place. Landfill owners are also required to produce annual reports on landfill gas reductions. Prior to these amendments, only landfills with a capacity in excess of three million cubic metres were required to have such systems. The new rules require gas collection systems for landfills that have a capacity exceeding 1.5 million cubic metres. As well, landfill operators are required to provide an annual report to MOE indicating the volume of landfill gas collected by the facility, the percentage of gas that was methane, and the amount of methane that was reduced either through faring or burning for power generation. Exemptions can be granted where the nature and quantity of gas generated at a particular site is not likely to be of significant concern. For a more detailed review of this decision, please see Section 4.8 of the Supplement to this Annual Report.
Organic Diversion Efforts
Organic waste, which is produced by households, businesses and other institutions, makes up as much as one-third of the municipal solid waste stream in Ontario and is the major source of methane in landfills. Significant gains have been made by municipalities in diverting household organics from landfills either through backyard composting programs, or curbside or depot collection. The overall volume of organics diverted from landfills through these efforts increased significantly between 2002 and 2007, from about 360,000 to well over 600,000 tonnes.
The provincial government recognizes the importance of such diversion efforts. In 2004, it established a goal to divert 60 per cent of Ontario’s non-hazardous solid waste from disposal by the end of 2008, and renewed these efforts in October 2008 by releasing a discussion paper on the province’s Waste Diversion Act, 2002 for public comment.
Energy Production from Landfill Gas
Landfill gas can be burned to generate electricity; however, both the volume and concentration of methane must be high enough to make this process work efficiently. The formation of methane depends upon the amount of organic waste in the landfill and the temperature and moisture content of the landfill. Some of Ontario’s municipal solid waste landfills, which are designed to allow a certain amount of rainfall to seep in annually, may generate enough gas with high enough methane concentrations to make energy production worthwhile. The gas is collected through a system of vertical plastic perforated pipes inserted into the landfill at regular intervals. Horizontal header pipes collect the gas and deliver it to the site where the power is generated, usually by means of an engine or turbine paired with an electrical generator. This electrical power is then fed into the power utility’s grid.
The efficiency of a methane capture system depends upon various factors, such as the placement of the pipes and the permeability of the containment materials around the landfill. Accordingly, the methane capture rate can be as low as 20 per cent or as high as 90 per cent. Any gas not captured by the system is eventually released to the atmosphere. The need to create higher methane generation rates (in order to make a gas collection and utilization system viable) could result in landfills designed to be wetter, simply because wetter material decomposes more quickly. Depending on the actual capture efficiency, higher fugitive methane emission rates resulting from wetter landfills could reduce, offset or even exceed the potential environmental gains from landfill gas capture and power generation.
ECO Comment
The ECO believes that the best solution to deal with greenhouse gases from landfills is to reduce or ideally eliminate, on a go-forward basis, the amount of organic matter that ends up in them. The ECO is pleased to hear that MOE has initiated a review of the Waste Diversion Act, 2002, with intentions to encourage the development and expansion of organic waste diversion programs, processing capacity and composting.
The ECO supports aggressive diversion programs, but urges that such programs be structured within the context of an overall solid waste management strategy.
The ECO is somewhat concerned about the conflicting messages that municipalities may be receiving from the provincial government with regard to organic waste. While the government is promoting increased diversion programs, these new requirements for methane collection systems may result in a situation where municipalities need to continue landfilling organic matter, rather than diverting it, in order to “feed” costly methane collection systems.
Finally, the ECO recognizes that zero organic landfill waste is not achievable in the near future and supports all efforts to minimize the environmental damage caused by current and legacy disposal practices. While initiatives to capture methane are supported, the ECO believes that some questions remain outstanding regarding the overall environmental efficacy of current landfill gas capture systems when methane production is accelerated.
| This is an article from the 2008/09 Annual Report to the Legislature from the Environmental Commissioner of Ontario. |
Citing This Article:
Environmental Commissioner of Ontario. 2009. "Landfill Gas Collection and Control Regulation." Building Resilience, ECO Annual Report, 2008-09. Toronto, ON : Environmental Commissioner of Ontario. 81-83.
