Post-Closure Care Factors: 18-Env-A6 Solid Waste Engineering and Management, December 2017, Q18

Question 18: Post-Closure Care Factors (3 marks)

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Three factors that must be considered in post-closure care: (1) Groundwater and leachate monitoring — continued sampling of the monitoring-well network and any residual leachate collection system, trended against regulatory limits, for the full post-closure care period. (2) Landfill gas monitoring and management — continued operation of the LFG collection/flare or energy-recovery system and perimeter/structure methane monitoring, since gas generation continues for years after the site stops accepting waste. (3) Final cover maintenance — periodic inspection and repair of the cap for erosion, differential settlement cracking and vegetation cover, since a degraded cover increases both infiltration (more leachate) and gas migration risk.

Topic: Post-closure care obligations

Key relations: Post-closure care period typically 25–30 years (regulatory minimum).

Why this works: These three factors are the same three ongoing obligations named in the long-term closure plan of Question 6, restated here at the more granular "what do you monitor and maintain" level — groundwater/leachate and LFG monitoring confirm the engineered controls are still working, while cover maintenance confirms the physical barrier that makes those controls effective is still intact.

Common pitfall: Treating post-closure care as complete once the final cover is built and initial monitoring shows no exceedance, rather than as a sustained multi-decade commitment that requires continued funding and periodic re-assessment.

Source: Tchobanoglous, Theisen & Vigil, Integrated Solid Waste Management: Engineering Principles and Management Issues, Ch. 13 (post-closure care); CCME, Guidance Document on Landfill Gas Management.

Question 18 of 18: Post-Closure Care Factors

Question 18: Post-Closure Care Factors (3 marks)