Anaerobic digestion of the Organic Fraction of Municipal Solid Waste (OFMSW) generates a mixture of methane (CH4), carbon dioxide (CO2) and water (H2O). Beyond the field capacity the water generated is collected and recirculated as leachate in Bioreactor Landfills (BLs.) Leachate recirculation has a profound advantage on biodegradation of the Organic Fraction of Municipal Solid Waste (OFMSW) in the landfills. Mature leachate from older sections of landfills (>20 years) and young leachate were blended prior to recirculation in the ratios 3/3 mature, 3/3 young, 1/3 mature-2/3 young and 2/3 old-1/3 young and their effect on biodegradation and biogas production monitored. In addition to analysis of the effect of blending old and new leachates, the study also analyses the effect of an open vs. a closed recirculation loop and the effect of organic loading rates of OFMSW in landfills. Data collected from initial batch tests supplement column bioreactors simulating bioreactor landfills with real world OFMSW from operational landfill facilities in Ontario, Canada. The results are conclusive that the biogas generation can be improved by up to 92% by blending the leachate in an open loop recirculation system as compared to a conventional closed loop system employed in landfills today.

Anaerobic digestion of the Organic Fraction of Municipal Solid Waste (OFMSW) generates a mixture of methane (CH4), carbon dioxide (CO2) and water (H2O). Beyond the field capacity the water generated is collected and recirculated as leachate in Bioreactor Landfills (BLs.) Leachate recirculation has a profound advantage on biodegradation of the Organic Fraction of Municipal Solid Waste (OFMSW) in the landfills. Mature leachate from older sections of landfills (>20 years) and young leachate were blended prior to recirculation in the ratios 3/3 mature, 3/3 young, 1/3 mature-2/3 young and 2/3 old-1/3 young and their effect on biodegradation and biogas production monitored. In addition to analysis of the effect of blending old and new leachates, the study also analyses the effect of an open vs. a closed recirculation loop and the effect of organic loading rates of OFMSW in landfills. Data collected from initial batch tests supplement column bioreactors simulating bioreactor landfills with real world OFMSW from operational landfill facilities in Ontario, Canada. The results are conclusive that the biogas generation can be improved by up to 92% by blending the leachate in an open loop recirculation system as compared to a conventional closed loop system employed in landfills today.

Dumping of municipal solid waste (MSW) generated due to anthropogenic activities in any barren land or out fields causes severe hazards to human populations, ecosystems and the environment. In order to avoid this, it is required to design landfills in an engineered and scientific manner. Therefore, it is necessary to understand the behaviour of landfills over a period of time, to design landfills for site specific conditions. In this thesis such an attempt is made to evaluate performance of conventional landfill system using a large scale anaerobic reactor in the laboratory. The performance of the containment (bottom liner and final cover) systems is evaluated through numerical modelling and reliability based analysis. Response Surface Methodology (RSM) is used to develop linear regression models. Influence of various parameters and their uncertainty on the reliability of the containment systems are studied for various scenarios and conditions. Reliability assessment of containment systems play a decisive role in taking remedial measures in order to reduce its adverse affects on the environment and human health in the vicinity of landfill sites. On the other hand, pre-assessment of risk guides the engineers, planners and decision makers in achieving the goal of sustainable solid waste management as well as safe landfills. The thesis also includes assessment of vulnerability of groundwater to contamination, identification and ranking of suitable sites for municipal solid waste (MSW) disposal in the Bengaluru district, using remote sensing and Geographic information system (GIS) integrated with analytical hierarchy process (AHP), a multi criteria decision making tool. The study considers various land use, geological, hydrogeological and environmental factors as criteria. As a result, two most suitable locations are identified around the Bengaluru city and their descriptions are provided. Further, reliability analysis of the suitability of sites is evaluated considering criteria as random variables. The proposed reliability based approach helps the decision makers and planners to choose site locations having low probability of environmental pollution. The provided methods in the thesis can be effectively used for engineered design of landfills.