Adsorption of heavy metals by biosolids admixtures.

This study aims to elucidate the potential of stabilized biosolids to reduce the leachate of metals from waste landfills. Adsorption of heavy metals (Cd, Co, Cu and Ni) on to biosolids and clay was studied using batch isotherms. These experiments determined the effect of contact time and initial concentration on adsorption of heavy metals on to clay and biosolids. The experimental data reveals that biosolid is more effective in adsorption of heavy metals Cd, Co and Ni than clay at higher concentrations. The isothermal data could be well described by Freundlich adsorption model. Metal concentrations in leachate can be reduced further using lime and cement admixtures. The results of the study demonstrated that biosolids stabilized with lime and cement is a more effective and lower cost adsorbent than clay, and could be used in landfill liners to retard the leachate of hazardous heavy metals. [ABSTRACT FROM AUTHOR]