Development of Leachate Treatment Method

Leachate generation from Gohagoda dumpsite is polluting the River Mahaweli. Therefore, it was essential to characterize the dumpsite leachate and to investigate low cost methods to treat the leachate through biochemical laboratory scale experiments. During the study period Gohagoda dumpsite produced high strength leachate. Average pH, electrical conductivity, salinity, dissolved oxygen, biochemical oxygen demand, chemical oxygen demand, total solids, total dissolved solids (TDS), volatile solids, of leachate were determined. The addition of food waste as a carbon source to treat leachate was experimented and incorporation of Azolla plant as a decontaminant was studied. The addition of food wastes did reduce most of the treatment parameters, although most parameters increased after the third day of treatment. Azolla plant demonstrated higher sensitivity to leachate water with optimal growth conditions observed at a dilution factor of 30. Under these conditions, Azolla showed removal efficiencies of conductivity, salinity, and TDS of 47.0 %, 33.3 %, and 41.4 %, respectively, while a lower dilution factor exhibited higher removal efficiencies. Therefore, Azolla plants can effectively be utilized as a decontaminant in subsequent stages of the leachate treatment process.