Metal Removal and Recovery from Mining Wastewater and E-waste Leachate

As industrialization and technology advancement rapidly increase, the global metal reservoir has been decreasing significantly along with high load of metal contaminated waste stream generation. Sustainable resource management has played a major role in many political decisions in which the idea to recover metals from waste stream was generated. This work provides the idea of metal recovery using a biological approach which is cost effective and less hazardous than chemical ones.

Metal contamination in the environment is a persisting global issue. The metal reservoirs in the earth have declined due to society’s needs and due to uncontrolled mining activities. Therefore, the idea to recover metals from waste streams has emerged.
In this thesis, cost competitive technologies such as adsorption using agro-wastes and precipitation using an inverse fluidized bed (IFB) reactor were investigated, with special emphasis on the recovery of base metals. Groundnut shell showed good potential for metal (Cu, Pb and Zn) removal. From artificial neural network modeling, the performance of the sulfate reducing bacteria (SRB) was found to be strongly pH dependent; the removal efficiency of Cu and Zn in the IFB at pH 5.0 was >97%. Electronic waste is a good candidate as secondary metal resource. The recovery of Cu from computer printed circuited boards (PCBs) using biogenic sulfide precipitation was investigated as well. Using this technology, Cu could be recovered at ~0.48 g Cu/g PCBs.