Evaluation of using municipal solid waste compost in landfill closure capsin arid areas

Covering systems of landfills involve partial or complete isolation of wast e materials from the surrounding environment. Available materials and manag ement practices in arid areas may not be adequate to fulfill the requiremen ts of the current regulations. This study investigates the performance of a native soil available in arid areas blended with municipal solid waste com post as an infiltration barrier layer in landfill closure cap design. Tests to determine different physical properties of the produced mixture were co nducted and the optimum blend of minimum hydraulic conductivity was selecte d. The effect of organic decomposition and thermal fluctuation prevailing i n the arid environment upon the changes in hydraulic conductivity was evalu ated experimentally. The developed mixture of 60% compost and 40% native so il was found to have a hydraulic conductivity 4.0 to 6.0x10(-9) mis. other tests were conducted to examine the effect of organic decomposition and the rmal fluctuations upon the hydraulic conductivity. From the hydraulic perfo rmance viewpoint, it was concluded that the developed mixture is an alterna tive. Some precautions are still needed in that case to eliminate the poten tial emission of gases from the cover material, anticipated settlement duri ng the active stage of biological degradation, and the increased possibilit ies of deterioration related to burrowing animals. (C) 2000 Elsevier Scienc e Ltd. All rights reserved.