Stabilization/solidification by hydraulic binders of metal elements from landfill leachate

Abstract

The objective of this work is to use stabilization/solidification (S/S) on the landfill leachates that often are heavily polluted by heavy metals and require proper treatment before discharge into the environment. The process consists of a S/S using a hydraulic binder in order to limit the solubility and mobility of the pollutants. While cement is the most used binder based on S/S values, in this study we substituted it by cement kiln dust (CKD) in two replacement ratios 25.50 and 100 %. The resulting effect on mechanical resistance and on retention of pollutants was evaluated. A metal (lead, iron and zinc) contaminated leachate from the landfill site of Sidi-Bouderham in Algeria was mixed with an amount of cement and cement kiln dust in different proportions in order to optimize our formulations. The smooth paste was obtained and a standardized test of the test specimens was analyzed for mechanical resistance after 7 and 28 d of setting. Our results show that F1P (100 % Cement) and F2P (75 % Cement + 25 % CKD) point on satisfactory mechanical strength and metal retention capacity. Our approach suggests a promising approach for remediation of polluted sites.