Rating of Municipal Solid Waste Dumps and Landfills as Source of Groundwater Contamination

EXECUTIVE SUMMARY In many of the third world countries like India, uncontrolled land disposal of municipal solid waste is a common practice even today. Various studies have indicated that the unregulated waste dumps and landfills cause serious environmental and human health hazards, one of them being groundwater contamination. In order to prevent further groundwater contamination from the uncontrolled municipal waste disposal sites, there is a need for their remediation. However, due to financial constraints, the required remedial actions can not be taken at all sites simultaneously. Therefore, a decision making tool is required to generate a priority list of polluting waste disposal sites on the basis of their groundwater contamination potential. This paper describes a new Groundwater Contamination Hazard Rating Model for municipal solid waste dumps and landfills developed to prioritise remedial measures at uncontrolled sites. The model is based on the source-pathway-receptors hazard chain. Source is the candidate landfill or waste dump, and is described by a number of parameters like landfill size, waste composition, landfill operating practices, and annual precipitation. Pathway is the medium for transport of the contaminants from the source to the receptors and is characterized by a number of parameters dealing with the leachate containment system, the vadose zone and the aquifer. The receptor is the groundwater and the users thereof in the vicinity of the source including the human population, crops, livestock and wildlife. Various model parameters dealing with source, pathway and receptors have been identified based on literature and expert opinion. The relative importance weights of various category parameters are derived using the Delphi technique. The source, pathway and receptor parameters are aggregated separately by using a combination of the multiplicative-additive algorithm and the fuzzy composite programming. A final score between 0 and 100, which is arrived at by combining source, pathway and receptor scores into one value, indicates the groundwater contamination hazard rating of a waste dump or landfill at any point in time during its entire leaching life. The hazard rating model presented here can be applied while the landfill is still in operation or after the landfill is closed. It can predict the peak value of the groundwater contamination hazard that a proposed landfill will have at some point in time during its leaching life, which can be used as important information for site selection, planning and designing of new landfills. The model has been applied on two waste dumps …