APPLICATION OF COAL ASH-BENTONITE MIXTURE AS LANDFILL LINER

Civil Engineering

Landfills are highly Engineering containment systems, designed to minimize the impact of soiled waste on the environment and human health. In case of economically developing countries the design of a liner varies, that depends upon number of factors such as potential of the landfill polluting the land and water environments, the local hydrogeology and meteorology, and the availability of suitable materials and monetary resourced. Landfill is a land disposal site for waste and its Preparation, management and control must be of the highest standard to minimize the risks to human health and the environment. Well‐constructed and maintained landfills are safer than open dumping sites. Landfill liners are exposed to various types of physical, chemical and biological processes which gets affected by leachate produced from the decomposition of waste dumps. The aim is to avoid any hydraulic connection between the wastes and the surrounding environment, particularly groundwater. To ensure this, the important characteristics for compacted landfill liners are; selection of materials, hydraulic conductivity, strength, compressibility and contaminant retention capacity. Compacted clay liners are of low cost, large leachate attenuation capacity and resistance to damage. Natural clay is often fractured and cracked and due to non-availability of suitable soil at a site, it is necessary to mix imported clay materials with industrial wastes to achieve a suitable material. Usually soil, which is rich in clay minerals is used for compacted liner materials. But instead of clay, mixture of expansive soil such as bentonite with fly ash can be used as compacted liner materials for their low hydraulic conductivity which is required to be less than 1.00×10^ -7 cm/sec. Bentonite was mixed with fly ash in 2,4 8,12,16, and 20% by dry weight.

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