Keywords: composting, cover soil, leachate treatment, lysimeter, rainwater infiltration, tropical landfill, compost mixture, mixed soil, rainfall intensity, filter materials, COD removal
Performance of soil and compost mixture in leachate purification at intermediate cover soil of tropical landfill
Leachate treatment was studied in simulated columns filled with different types of cover materials, i.e. (a) natural soil, (b) mixture of soil and planting soil, (c) mixture of soil and compost at 2:1 ratio and (d) mixture of soil and compost at 1:1 ratio. Filter performance was evaluated at different water application rates equivalent to rainfall intensity of 25, 50 and 100 mm/d. Leachate characteristics were affected by water application rate. Its concentration was highest at the beginning and decreasing with time. The use of mixed soil as filter materials initially helped to improve leachate quality but their treatment efficiencies diminished when maximum soil adsorption capacity has been reached. Soil materials could remove BOD, colour and TKN by 32.78, 48.93 and 72.61% in average at a rainfall intensity of 50 mm/d. Introduction of compost as filter materials could enhance COD removal efficiencies but also contribute colour in treated leachate.