Analysis of soil effects as leachate filter: A case study of TPA Mandung Tabanan

Department Civil Engineering, Universitas Udayana, Bali, Indonesia

^* Corresponding author: kdharmayani@yahoo.com

Abstract

The accumulation in large volume of solid waste in the area of TPA Mandung is creating a new serious problem since the leachate is extremely increasing. The spill drastically contaminates the groundwater and the surrounding environment because the wastewater treatment plant isn’t working on full capacity. Based on those facts, it is necessary to start researching on how the leachate influences the soil characteristics, and how to get the soil to provide a proper filtration. The samples of soil and the leachate from TPA Mandung have, at first, been collected; soil properties have been physically and mechanically tested, while the leachate characteristics have been determined from the parameters of the contained substances. The leachate filtration was performed simultaneously with a hydraulic conductivity test simply varying its height from 7 cm, 9 cm, and 11 cm. The water drained from the hydraulic conductivity test has been reexamined to determine the changes in the leachate parameters after passing through the soil. The K value (hydraulic conductivity coefficient) in the soil hydraulic conductivity test sampled with height 11 cm, 9 cm, 7 cm, were respectively 0.000050 cm/sec, 0.000062 cm/sec, and 0.000065 cm/sec. The results showed a decrease in the coefficient of hydraulic conductivity along with the addition of leachate and the variation in sample height. The leachate in TPA Mandung before and after filtration had COD, BOD5, TSS, TDS and oil levels that exceeded the permitted threshold according to Regulation of Minister of Environment No. 5 of2014 concerning Wastewater Quality Standard.