Experimental study on the treatment of chromium-containing wastewater by aged refuse

Biosorption-coupled reduction, as an effective and low-cost technology treating chrome-containing wastewater, has become a significant concern worldwide. This paper presents the results of two comparative trials, one column reactor was filled with unpasteurized aged refuse and the other sterilized, aiming at evaluating the performance of aged refuse for Cr(VI) removal from simulation wastewater. The results indicated that the Cr(VIi) removal efficiency was slightly better in unpasteurized chrome, which demonstrated that micro-organisms had made a tiny contribution. In order to elucidate the mechanism of the process, the retained medium was characterized in terms of Cr(VI) and total chromium using ultraviolet-visible (UV-vis) spectroscopic techniques. Isotherm tests showed that equilibrium sorption data were better represented by Langmuir than Frendlich model. Two main processes involved were: adsorption on the surface and reduction into Cr(III) mediated by the organic matter or anaerobic microbial metabolism of the bacteria residing in aged refuse. Thanks to the proven efficiency and the low-cost, the method can represent a valid alternative to conventional approaches to chromium remediation. (C) 2012 Selection and/or peer-review under responsibility of Basel Convention Coordinating Centre for Asia and the Pacific and National Center of Solid Waste Management, Ministry of Environmental Protection of China.