Development of a Laboratory Scale Filter Using Laterite to Treat Landfill Leachate

Abstract

AttachedMunicipal Solid waste (MSW) is a severe problem in Sri Lanka due to lack o f proper solid waste management system, and leachate is one o f the major issue associated with MSW. Around 95% o f MSW is disposing into poorly managed open dump sites, where do not have methods to treat the leachate. Therefore, proper low -cost leachate treatment method is highly demanded in Sri Lanka. This study was carried out to develop a laboratory scale filter using laterite based earth materials in order to remove the pollutants from leachate. Study the durability o f the filtering media and possible composition are the other aims. Six laterite soil samples were collected from six different locations in western province were geochemically tested prior to use as a filtering media. The experiment setup was designed with five filter columns. Four columns were made using laterite soil by mixing with 10%, 20%, 30%, and 40% compost ratios by weight. Remaining column was made from pure laterite as a control. Each column consists o f 2 kg o f filtering medium. Leachate from Karadiyana landfill site was used for the experiment after 50% dilution. Leachate feeding was done, with total volume o f 750 ml per day by keeping two days o f recovering time between each feeding session. The removal efficiencies o f BOD, COD, TSS, TDS, conductivity, pH, Oxidation-Reduction Potential, phosphate, nitrate, and selected heavy metals such as Cu, Mn, Zn, Cd, N i, Pb, and Fe were analyzed in fifty days o f time period. Results indicate that, there are different filtering efficiencies for different parameters. In each column, pH level o f the filtrate was within 6.3-8.0 and all were contributed to oxidize in the influent leachate. Filtering efficiencies for the important pollutants o f leachate such as BOD, COD, phosphate, nitrate, and all the heavy metals were stable in considerable level even after fifty days o f experiment except TSS, TDS, and conductivity. This indicates higher level o f durability o f the filtering materials. In general, life time o f the filtering media has been enhanced by the batch w ise feeding method. Therefore, further feeding o f leachate is needed to select the suitable filtering media.