Preliminary Study on The Potential of Hybrid Rice Husk with Kapok Fiber and Hybrid Rice Husk with Coconut Fiber as Landfill Liner Material

Abstract

Abundance of agricultural waste in Malaysia namely rice husk (RH), kapok fiber (KF) and coconut fiber (CF) has been increasing over the years. This cause disposal problem and air pollution problem from burning activity. In line with the Malaysian Government Policy on the application of green technology concept through the 5R's practice, this agricultural waste has a potential to be commercialized as material for landfill liner. A factor that governs the workability of landfill liner materials is the permeability should be less than 1x10 -9 m/s. Therefore, a low permeability material needs to be installed to minimise the environmental impact on the leachate intrusion into groundwater. A series of standard tests to find environmental and geotechnical properties such as atterberg limit test (liquid limit, plastic limit, compaction test), permeability test (falling head method), leachate characteristics and heavy metal test were conducted at various ratio of hybrid materials (KC:RH and KC: CF in the ratio of 1:1 and 1:2 respectively). Experimental results confirmed that the hydraulic conductivity of the mixture of KC:RH:KF in the ratio of 1:1:1 is 7.29 x 10- 11 m/s was less than 10 -9 m/s, satisfying the requirement for landfill liner materials. Heavy metal testing showed that this hybrid material (RH:KF and RH:CF for ratio 1:2) were able to reduce at least 50 % of the leachate contaminants. The proposed hybrid materials (RH:KF and RH:CF) is a green material for the landfill (as it can improve heavy metal adsorption), increase the workability of the landfill by improving the conductivity of the conventional liners), minimizing manpower on site (no need expertise for installation) and reduction in cost (in terms of the use of waste materials).