Abstract:
The landfill- leachate consists of different organic and inorganic compounds that may be either dissolved or suspended, which may pose hazards to receiving water bodies. It may be toxic to life or may simply alter the ecology of the stream or watercourse if not removed by treatment. Depending on the geographical and geological nature of a landfill site, leachate may seep into the ground and possibly enter groundwater sources. Therefore proper leachate treatment is very essential. Attached growth technologies have successfully been used for landfill-leachate treatment. If naturally available low cost materials can be used as packing media rather than using expensive materials such as plastic, synthetic polymers and crushed rocks, attached growth process would be a prominent technology in the area of landfill-leachate treatment. Hence the aim of this study was to utilize low- cost locally available materials such as coconut coir fiber, rice straw, rice husks and saw chips as packing media in laboratory scale anaerobic filter columns to treat landfill-leachate. The leachate was collected from the Galle Municipal Council dumpsite. The filter column experimental set-up consisted of 4 columns each with 35 cm height and 8.9 cm inner-diameter. The initial height of packing media was 24 cm. The influent which was stored in an overhead tank was loaded on to each column via a shower. Approximately a constant application rate was maintained by adjusting a valve. The effluent was collected in an effluent tank kept below each column. Influent and effluent were characterized in terms of several wastewater parameters. All the columns were sealed to fulfil anaerobic conditions. There were two experimental runs with durations 9 and 7 days. The degrees of contaminant removal of different packing media did not show much variation with each other. There was a reduction in organic matter, total nitrogen, nitrate nitrogen, total dissolved solids, chlorides and sulfates. Anaerobic digestion, adsorption and denitrification could be principal treatment mechansms.The rate of removal of COD and chlorides in the experimental run 1 were excellent with rates greater than 80 and 90 percent, repectively.
