Effects of Compaction Parameters on Heavy Metal Mass Transport in Ankara Clay Liner: Experimental Approach

Authors: M. ZEKİ ÇAMUR, FÜSUN CANPOLAT, HASAN YAZICIGİL

Abstract: Mass transports of Cl, Cd, Cr, Cu, Fe, K, Mn, Ni, Pb and Zn ions through the Ankara clay liner was prepared under two different compaction conditions, and were studied experimentally on the bases of sorption and hydrodynamic dispersion processes. According to geotechnical tests, the Ankara clay material is highly plastic, inorganic clay having a liquid limit of 73, a plastic limit of 29 and a plasticity index of 44. Optimum compaction of the material requires 32% water content and 1.413 g/cm^3 dry density. Two materials, prepared using half of the optimum water content but optimum energy conditions (I) and optimum water content but half of the optimum energy conditions (II), have the effective porosities of 0.35 and 0.40, respectively. Hydraulic conductivities of these materials (I and II) were 3.1-4.38x10^{-8} cm/s and 916-1057x10^{-8} cm/s, respectively. Dispersivities determined through column experiments were 0.88 cm and 1.78 cm in materials I and II, respectively. Mass transports of the ions were minimum in the material that were prepared using optimum conditions (diffusion dominant mass transfer) but maximum in the material that were prepared using optimum water content but half of the optimum energy conditions (advection dominant over diffusion type of mass transfer). The Ankara clay material is suitable for a liner design in waste disposal sites as long as it is compacted under optimum energy conditions.

Keywords: diffusion, dispersivity, hydrodynamic dispersion, clay liner, Ankara clay

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