Sustainable gold mining wastewater treatment by sorption using low-cost materials; Proefschrift Wageningen en UNESCO-IHE Institute for Water Education Delft.

Abstract

Among the various wastewater treatment technologies, the sorption process is considered better because of lower cost, simple design and easy operation. Sorption technique was employed to remove heavy metals from gold mining effluent using natural and plant materials. An assessment of the effluent quality of a gold mining company in Ghana indicated that arsenic, copper and cyanide were the major pollutants in the process effluent. The research showed that coconut shell (CS) can be an important low-cost sorbent for Cu(II) removal from inorganic wastewater. However, arsenic removal was only possible with iron-oxide-coated sand (IOCS). The removal of Cu(II) was mainly through an ion exchange mechanism. The sequential sorption-desorption characteristics of Cu(II) on CS and IOCS showed that both sorbents are good for Cu(II); but cyclic sorption and desorption using 0.05 M HCl was only feasible with CS. The intraparticle diffusion controls the rate of sorption in this study. Arsenic and copper were successfully removed from the effluent by the studied materials. The research showed that the down-flow fixed-bed treatment configuration is an ideal system for the simultaneous removal of copper and arsenic from low concentration gold mining effluent, in addition to other heavy metals present in very low concentrations