This paper describes a study that uses a fitted modeling approach to calculate methaneemissions during the operation and post closure care period of a bioreactor and a regular landfill.It focuses on the feasibility of using soil cover to eliminate landfill methane emission before,during or after post-closure care period such that the active gas control system could be phasedout as part of the termination of post-closure care. A numerical model had been developed tosimulate landfill gas emission before, during, and after post-closure care period by using landfillgas generation curve. The soil physics model was used in combination with the USEPALANDGEM to directly estimate surface emissions and oxidation from an example landfill duringits operation and post closure period. When the gas collection system is operational, thecollection efficiency of the gas collection system was assumed to be 75%. The remaininglandfill gas (25% of total gas generation) was assumed to escape through the landfill cover. Gascollection was assumed to start during the first year of waste acceptance of the bioreactorlandfill, while it would start only after five years of operation for the case of the regular landfill.The simulations showed that surface emission from bioreactor landfill were lower than thosefrom the regular landfill during the simulated 52 years. Thirty years after closure, surfaceemissions were zero from the bioreactor landfill even when the gas collection system was turnedoff. Emissions from the regular landfill continued 30 years after closure and increased as soon asthe gas collection was turned off.
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