Bentonite Enhanced Soil as an Alternative Landfill Liner in Rikut Jawu, South Barito

Abstract

The use of geosynthetic materials has developed very rapidly; however, the use of clay as a mineral barrier is a necessity to meet environmental requirements to protect groundwater from leachate in landfills. Generally, the soil used as a mineral barrier is local land or close to landfill locations. It is just often found that local land does not meet the requirements as a barrier. This condition occurs in landfill development in Rikut Jawu, South Barito regency. The permeability of the surrounding land that has been compacted is still higher than the required permeability. An effort is needed so that the permeability can be accepted. This paper describes the effort to minimize the permeability of sandy loam soils in Rikut Jawu to meet the requirements as a landfill liner. This research was conducted in the Laboratory of Soil Mechanics, University of Lambung Mangkurat. Disturbed soil samples were mixed with bentonite with the percentages of 1%, 5%, 10%, 15%, 20% based on dry weight. Water was added depending on the optimum moisture content of each mixture that was obtained from the Standard Proctor compaction test. Series of the permeability tests were performed according to ASTM standard. In order to investigate the time effect, the samples were cured for periods of 3, 7, and 14 days. The result shows that the presence of bentonite in the mixture influences the permeability (k) of samples. The permeability of samples decreases from 1.3 × 10-5 cm/s to 3.6 × 10-7 cm/s. The result also found that the permeability of bentonite enhanced soil was also influenced by the water content of compaction. The curing times of 3, 7, and 14 days do not significantly affect the permeability. The percentage of bentonite to be used as a clay liner to fulfill permeability requirement is 50%. The further efforts are suggested and discussed in the paper.