The selection of a landfill leachate management strategy in order to shorten the aftercare period and reduce the leachate management cost is challenging. For decision making, it is important to understand 1) the main indicators of long-term leachate performance, 2) the target levels of these indicators must reach to indicate the end of the aftercare period and 3) the strategy to meet the target level of the indicators within the shortest time. The aim of this thesis is to establish a leachate emission prognosis tool for the determination of the length of the aftercare period and to use models to test the effects of different leachate management strategies on the length and overall leachate management costs of landfill aftercare. The first part of the research is a study of municipal landfill stabilization and emissions, made by systematically describing the long-term landfill leachate and gas (LFG) emission performance achieved by landfill simulators (landfill simulation reactors, LSRs). The results give a comprehensive picture of the waste biodegradation progress during the landfill aftercare period. The second part of the research is an evaluation of the feasibility of a biological on-site process to pretreat the leachate (mainly total nitrogen [TN] removal) for leachate recirculation, direct discharge and indirect discharge purposes from both technical and economic points of view. It is integrated with a case study of a cost estimation based on a real landfill condition as an important part of the study, conducted to define the applicability of the crucial leachate management alternatives. Based on the results of the LSR and biological leachate nitrogen removal studies, the possibility and feasibility of optimizing landfill leachate management and treatment were clarified by developing models for the estimation of long-term emissions from landfills of different sizes and evaluating the best options for leachate and nitrogen management during the aftercare period. The models developed can be used to express the importance of different target parameters and estimate the length of the aftercare period for a landfill that is effective at optimizing a cost-effective aftercare strategy. The modelling findings show that in conventional scenarios, without leachate recirculation, the aftercare period can last up to several centuries. With the highest leachate recirculation rate, the aftercare period can be shortened substantially, to 25 years and 75 years, in medium-sized and big landfills respectively; though this is technically more challenging to do for big landfills. These scenarios also showed that the lowest total and average (per m3) leachate management costs can be achieved at about 60% of the costs of conventional scenarios during the aftercare period.
|Julkaisun otsikon käännös||Leachate management in the aftercare period of municipal waste landfills|
|Tila||Julkaistu - 2013|
|OKM-julkaisutyyppi||G5 Tohtorinväitöskirja (artikkeli)|