AMENDED LATERITE SOIL WITH FLY ASH AS LANDFILL LINER

Abstract

Here in Malaysia, which has a daily generation of more than 30,000 tonnes of municipal solid waste (MSW),  disposes of approximately 95% of MSW directly into landfills. Landfills are the final destinations of the majority of waste generated in most urban areas. A liquid that permeated through waste and contains heavy minerals and suspended materials are defined as landfill leachate (Yamusa, et. al., 2019). Compacted natural soils are often used as liner materials in engineered landfills to minimize the environmental impacts attributed to landfills by preventing the migration of leachate and landfill gases into the environment and groundwater (Lee, 2019). Lining systems for waste containment facilities can be enhanced if they are constructed with reactive materials, that is, materials that retard movement of solutes, promote biodegradation, or reduce chemical conversion (Chakradhar & Katoch, 2016). Three objectives were set for this research which includes determining the physical properties of laterite soil, optimum percentage of fly ash to be added into laterite soil, and identifying the permeability of amended laterite soil with fly ash as a suitable landfill liner. This study is an attempt to assess the use of coal ash (fly ash) mixing with abundant soils (laterite soils) as potential landfill liners. In this study, physical properties and compaction of soils will be conducted to identify the soil profiles of the laterite soil. 15%, 20%, and 30% of fly ash will be used to assist in strengthening the soil. This study will broaden the research of materials being used as a landfill liner and give a bigger option for landfill operators to have more information about the use of material such as a mixture of laterite soil and fly ash. As result, the physical properties of laterite soil are 21% and 27% of moisture content based on samples 1 and 2. At the same time, its liquid limit is 42% and 55%, plastic limit of 31% and 36%, plasticity index of 11 and 19 while the particle size distribution is classified as sandy clay (SC) and poorly graded for both the samples. Laterite soil location 1 with 20% amended fly ash has the highest dry density of 1.87 mg/m3 compared to location 2 with 20% amended fly ash of 1.64 mg/m3. As for consolidation test, location 1 with 20% amended fly ash has permeability value of 2.564 x 10-10 cm/s while location 2 has value of 3.391 x 10-10 cm/s which has surpassed the requirement of < 1x10-7 cm/s. 

Keywords: Consolidation test, fly ash, landfill liner, laterite soil, permeability