Chemical Engineering Research & Design, Vol.120, 231-239, 2017
Innovative use of drinking water treatment solids for heavy metals removal from desalination concentrate: Synergistic effect of salts and natural organic matter
Concentrate treatment and management is one of the most challenging issues that hinder implementation of water reuse and desalination. Drinking water treatment solids (DWTS) could be an effective low-cost sorbent for removal of heavy metals from desalination concentrate to improve water recovery. It provides an innovative approach to reuse the waste streams generated during drinking water treatment and desalination. In this study, the operating conditions and synergistic effect of salts and natural organic matter (NOM) on removal of metal cations (Cd, Cu, Ni, and Pb) in reverse osmosis (RO) concentrate and synthetic solutions were investigated using DWTS. The amount of heavy metals removed from concentrate increased with increasing pH and initial metal concentration. Cu and Pb were almost completely removed by sorption and precipitation. Higher concentrations of NaCl, CaC1(2), Na-2 SO4, and presence of NOM in RO concentrate decreased the sorption of Cd and Ni due to ion competition, complex formation, and simultaneous chelation. This study demonstrated using DWTS to adsorb heavy metals from desalination concentrate is an environmental friendly and economical approach for sustainable management of concentrate. (C) 2017 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.
Keywords:Sorption;Precipitation;Metals removal;Desalination concentrate;Drinking water treatment solids;Natural organic matter