Investigation on Selected Khulna Soils as a Potential Base liner for Sanitary Landfills

Abstract

Environmental protection is now one of the goals parallel to economic growth in the development policies throughout the world. Waste and its associated environmental problems specially in the urban areas have raised significant concern in both Government and Public authorities of Bangladesh. Among the several methods of solid waste management, landfilling method of waste disposal is considered as the cheapest and most prevalent solution in the majority of the countries. The most important part of the design of a sanitary landfill is the impervious liner. This type of design is practical when clay layer is present nearby or on the construction site within limited financial, technical and human resources. Some representative Khulna soils have been investigated for its workability, geotechnical properties including mineral identification. A series of laboratory tests was conducted on selected soil samples, which are widespread and readily available over a considerable part of Khulna, to assess whether it could be compacted as hydro-geological barrier in waste disposal landfills. Index properties, compaction characteristics, and hydraulic conductivity of most of the investigated soil samples indicate that it is inorganic, plastic, inactive, moderately expansive (due to presence of Montomorillonite and Vermiculite) and of fair attenuation capacity for inorganic/organic contaminants. The results of hydraulic conductivity tests illustrate that hydraulic conductivity lower than 1x10-7 cm/s can be achieved using a broad range of water contents and compactive efforts. These f1ndir2s suggest that the selected Khulna soil can be potentially utilized as compacted soil liner material. It is of special interest for Khulna zone, in Bangladesh, because there are no alternative mineral raw materials for liners of landfills.