Soil-Compost Mixture as Alternative Material for Soil Cover Landfill

Abstract

One of typical problem in a developing country is the lack of controlling odors, vectors, fires, and litter in the waste landfill. It is known that this problem can be reduced by landfill. However to maintain cover material always available, it is uneasy, especially due to limited budget. This study intends to propose compost-soil mixture as an alternative material using residual soil cover from completed waste landfill. In order to investigate and assess the geotechnical properties of soil-compost mixture as an alternative material, several tests were conducted such as compaction, unconfined compression, and permeability tests. Compaction tests showed 0.4%, 0.8% and 1.2% of compost in soil mixtures results the values of dry density in the range between 1.297 g/cm3 and 1.330 g/cm3, which meet the minimum requirement according to Indiana environmental department USA. Shear strength of compost-soil mixture that derived from results of unconfined compression tests, reduced slightly for additional compost without curing time. However, the values increased sharply for 3 and 7 days of curing time. All the shear strength values of 0.88 kg/cm3 to 34.76 kg/cm3 passed the minimum requirement for cover material according to Environmental Protection Agency (EPA) and Environment Agency. In case of ability of the soil mixture to transmit water, permeability coefficient were 1.5 × 10−3 cm/sec, 7 × 10−4 cm/sec and 3 × 10−4 cm/sec for 0.4%, 0.8% and 1.2% of compost respectively. Referring to modern sanitary landfill and design, it was shown that, the soil mixtures meet minimum requirement for permeability coefficient. To sum up, compost-soil mixtures with composition tested can be considered as material alternative for soil cover in landfill.