Post-closure Care Completion at Msw Landfills and Residual Risks

(2011) " Post-closure care completion at MSW landfills and residual risks " , In: Proceedings 4th International Workshop " Hydro-physico-mechanics of landfills (HPM4) " , SUMMARY: In this work we present a modelling approach to evaluate residual environmental risks in view of different post-closure management strategies. Potential emission rates of a landfill are estimated based on different scenarios used to illustrate the effects of different conditions within and around the landfill. The effect of the scenario emissions is evaluated at different points of compliance and tolerable leachate emission levels at the source are determined based on a reverse risk assessment approach. The evaluation methodology is illustrated for a closed MSW landfill and post-closure care (PCC) durations are estimated for this landfill. Depending on the chosen PCC strategy the duration of PCC at the site may vary between several decades and more than a century, with ammonia-nitrogen in the leachate being the critical parameter. However, apart from ammonia emissions additional criteria need to be met in order to release the landfill from post-closure care (e.g. custodial care program and after-use limitations).