Application of a novel strategy-Advanced Fenton-chemical precipitation to the treatment of strong stability chelated heavy metal containing wastewater

Industrial and remedial processes produce wastewater containing chelated heavy metal. Chelated heavy metal containing wastewater needs to be treated not only for the toxic heavy metal, but also for the chelating agent. The treatment of strong stability chelated heavy metal wastewater is a hot and difficult issue in these years. To solve this problem, a novel strategy, advanced Fenton-chemical precipitation process (AF-CPP) is proposed to address chelated heavy metal containing wastewater. The process uses zero-valent iron and hydrogen peroxide for degrading the chelated compound, followed by alkali precipitation of heavy metal. NiEDTA was selected as a model of strong stability of chelated heavy metal pollutant. This process can remove not only nickel ions, but also reduces COD values. Parameters affecting nickel removal are discussed. At optimum condition, the nickel removal efficiency attained was 98.4% and the residual concentrations of nickel fell below the value stipulated in Integrated Wastewater Discharge Standard of China (GB8978-1996). AF-CPP appears promising and effective for the treatment of strong stability chelated heavy metal containing wastewaters. (C) 2012 Elsevier B.V. All rights reserved.