Question 3 of 16: Strategy to Reduce Greenhouse Gas Emissions

Question 3: Strategy to Reduce Greenhouse Gas Emissions (10 marks)

Question text not reproduced: the examination questions are © Engineers and Geoscientists BC. Open the official past paper (linked at the top of this page) to read the question, then follow the worked solution below.

A defensible GHG-reduction strategy attacks the problem at every stage of the waste hierarchy, since landfill methane (the dominant SWM greenhouse gas) is only one of several emission sources. Upstream, reduce the organic fraction reaching disposal: expand curbside organics (food and yard waste) collection paired with a municipal composting or anaerobic digestion facility, since diverted organics never generate landfill methane in the first place — this is typically the single largest-leverage measure available. At existing and future landfill cells, maximize gas capture: install an active landfill-gas collection and flaring (or, better, energy-recovery/utilization) system as early in the cell's life as practical, since methane has roughly 25–28× the 100-year global-warming potential of CO₂, so capturing and combusting it (converting CH₄ to CO₂) delivers an outsized GHG credit per tonne captured. Reduce collection-fleet emissions: route optimization, right-sized/lower-frequency collection, and a transition to low-carbon collection vehicles (CNG, hybrid or electric) cut the fuel-combustion component of the SWM carbon footprint. Credit and pursue avoided emissions: materials recycling and energy-from-waste both displace virgin-material extraction/manufacture or fossil generation, and should be counted (via a life-cycle accounting approach, see Q9) as offsets against the municipality's SWM emissions inventory, not evaluated on facility-gate emissions alone. Finally, the strategy should be quantified and tracked against a baseline inventory (following IPCC/ECCC solid-waste GHG accounting methodology) so the municipality can verify actual reductions and prioritize the measures with the best cost-per-tonne-CO₂e avoided.

None of these measures is a one-time fix: organics diversion capacity must scale with population growth, gas-collection systems need periodic well additions as new cells open, and the fleet-transition timeline depends on vehicle replacement cycles already budgeted for other reasons. A realistic implementation plan therefore phases these measures over a multi-year capital planning horizon rather than proposing them as simultaneous, one-time investments.