"USE OF LATERITIC SOIL AMENDED WITH BENTONITE AS LANDFILL LINER "

The main objective of this study is to find the usefulness of laterite soil amended with bentonite as liners in landfills. The minimum requirement of a liner for landfill is it should have a hydraulic conductivity less than 10 cm/sec. Various proportions of lateritic soil blended with bentonite have been tested to suggest a suitable liner. This paper presents experimental results obtained on hydraulic conductivity of lateritic soil blended with bentonite. Bentonite content in the blend is varied as 0%, 10%, 20% and 30% to the dry weight of lateritic soil. The solute concentration used are Deionised water, 5 mM of K2Cr2O7 0.5 M of CaCl2 and 0.5 M of NaCl. Hydraulic conductivity value decreased from 7.18 x 10 cm/s to 1.894 x 10 cm/s when permeated with deionized water (DIW) when bentonite content was varied from 0 to 30%. When 5mM of K2Cr2O7 is used as a solute k value decreases with increase in bentonite content as the precipitate formed clogs the pores in the sample. Similar results were obtained with 0.5M CaCl2 and 0.5 M of NaCl. Of all the blend 80%-20% laterite-bentonite blend is found as the best material to be used as liner in a landfill