Experimental Study on Utilization of Waste Cement Kiln Dust-Sand Soil Mix for Landfill Liner

In this paper, an extensive laboratory program has been carried out to investigate the effectiveness of using waste cement kiln dust (CKD) and sandy soil mix as a liner for municipal landfills. Recently, the environmental concerns related to Portland cement production in terms of global warming (emission of CO2) and disposal of CKD are becoming increasingly substantial. Researchers are always working not only on finding new alternatives for landfill liners, which prevent (or reduce up to acceptable levels) the aqueous contaminants, but also the low-cost solution is one of the important goals. Therefore, the main objective of this research work is to introduce a landfill liner material that satisfy the standards as well as represents an economic and friendly-environmental solution for disposal of waste CKD which causes a critical environmental problem for some of developing countries. Four different mixes of sand and waste CKD, which have the following percentage by weight (including: 10%, 20%, 30%, and 40%), were prepared and tested in the laboratory. The results indicated that the mix which has CKD content of 40% by weight, succeeded in achieving extremely low hydraulic conductivity (k=6.5*10-10 cm/sec) although the mix was subjected to the effect of synthetic leachate as permeating fluid (i.e., under sever operation conditions). Thus, waste CKD and sand mix is a cheap, yet effective, alternative for municipal landfill liners compared to other conventional waste liner materials like cement and lime.