Canadian landfill gas production: Improving the model to estimate present and future methane production

Landfill gas, consisting primarily of methane and carbon dioxide, negatively affects human and environmental health. Its production and ultimate release into the atmosphere contribute to greenhouse gases and global warming. Accurate portrayals of current and future Canadian landfill-gas production guide appropriate methods for its mitigation. Without adequate knowledge regarding how the landfill environment operates, it is difficult to employ an environmentally friendly and cost effective management strategy. Modeled projections can provide insight to guide current and future policy decisions regarding the control and prevention of methane production.; This thesis improves current and future Canadian landfill methane production models, thereby advancing the knowledge used to select waste management and reduction strategies. Other objectives achieved include: (1) choosing a landfill gas model that best predicts methane production, (2) advancing the science of model inputs and (3) predicting future methane production based on current and prospective waste diversion practices.; The German EPER, TNO, Belgium, LandGEM, and Scholl Canyon models were tested for their suitability to model methane production for 35 Canadian landfills. A modified Scholl Canyon/LandGEM model, the "Sawyer Model" best calculated methane production, initially yielding a relative percent error of 19% and p=0.2501. Inputs for this model, decay rate (k) and methane generation potential (Lo), were reevaluated to best fit the measured data. Decay rates were trended with annual precipitation, improving the methodology used to calculate site-specific values. Methane generation potentials were assessed using site-specific and provincial waste composition data. Their calculated values were determined to be 10% less than that required to mimic Canadian landfill conditions successfully. Using these modified/improved inputs, the "Sawyer Model" yielded a median of -2% and p=0.5538. Although this change in Lo increased the percent error, the likeness between the measured and modeled data changed from moderate to high. Other variables not currently included in the "Sawyer Model" were assessed for their relationship/contribution to methane production. Current waste-in-place amounts (>10 Mt of waste versus <10 Mt of waste) and landfill operating status (closed versus operating landfills) were found to have significant relationships with methane production and should be considered when modeling landfills. Finally, four landfills were modeled to the year 2025 under five different waste diversion scenarios, illustrating that methane recovery projects are viable under a variety of waste diversion scenarios and in conjunction with recycling/composting initiatives.