Effects of Leachate Concentration (Na+, Pb2+, COD) on Non-Darcy Flow of Compacted Clay

Abstract

AbstractWaste placed in landfills may produce pollutants with a high concentration of complex components from chemical and biological degradations. The hydraulic conductivity and threshold gradient of the clay liner are affected by the high concentration of complex components. In order to study the influence of leachate concentration on permeability of compacted clay, three pollutants namely Na+, Pb2+ and COD were selected to conduct permeability study for compacted clay. COD is abbreviation of chemical oxygen demand. COD solution was prepared from dissolved glucose for the experiments in the paper. Flexible wall permeameter was adopted to perform a series of laboratory experiments. The results showed that Na+, Pb2+ and COD concentration increased, the hydraulic conductivity increased and the threshold gradient decreased. When three solutions were provided with the same concentration, Pb2+ had the greatest influence on hydraulic conductivity and threshold gradient of saturated compacted clay, followed by Na+ and COD solution. In the specific environment of landfills, COD had the greatest influence on hydraulic conductivity and threshold gradient of saturated compacted clay, followed by Na+ and Pb2+ solution, which meant it was necessary to conduct further studies on the effect of COD solution on hydraulic conductivity and threshold gradient of saturated compaction clay.KeywordsMSW landfillCompacted clayLeachate concentration (Na+, Pb2+, COD)Hydraulic conductivityThreshold gradient