Question 9 of 20: Strategy to Extend Landfill Life

Question 9: Strategy to Extend Landfill Life (4 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 life-extension strategy attacks both sides of the airspace balance — reducing the volume that must be buried, and increasing the volume the existing footprint can hold — and should be proposed as a combined package: (1) waste diversion — expand source-separated recycling and organics/composting programs (see Questions 1 and 17) to reduce the tonnage actually landfilled; (2) improved compaction practice — increase compactor passes and reduce lift thickness at the working face to raise in-place density (see Question 4), directly reducing airspace consumed per tonne; (3) reduced daily cover volume — substitute alternative daily cover (tarps, foam, spray-applied cover) for soil cover, since soil cover itself consumes 10–15% of airspace with no waste-holding benefit; (4) vertical expansion (over-height permit) — where geotechnically and visually feasible, seek regulatory approval to raise the final grade above the originally permitted height, adding capacity without expanding the footprint; (5) lateral expansion onto adjacent land, if available and permittable; and (6) landfill mining of an older, unlined or low-density cell to reclaim airspace and recover recyclables/RDF (see Question 11). The recommendation should quantify the airspace gained by each measure and prioritize the lowest-cost, fastest-to-implement options first. Because these measures are not mutually exclusive, the strongest strategy is a combined package rather than a single lever: diversion programs typically take longest to reach full effectiveness (requiring public-education ramp-up) while compaction and cover-material changes can be implemented almost immediately at the working face, so a phased rollout that captures the fast operational wins early while the slower policy-driven diversion programs build participation gives the community the most airspace relief in the shortest time.