Biological Treatment of Heavy Metals by Sulfate Reducing Bacteria

The aim of this project is to design and construction a new and developed system for treatment of heavy and toxic metals from industrial wastewater, in 1.5 and 500 litter bioreactors. In this project, we studied treatment of the different synthetic and industrial waste effluents in different condition. We will use two sludge blanket bioreactors. One of them in laboratory scale and the other in the pilot plant scale. In the laboratory scale there are some 1.5 litter sludge blanket bioreactor. In the pilot plant, there is a 500 litter bioreactors for treatment of industrial wastewater.We used some chemical reaction for pretreatment of industrial wastewater. These reactions are use for neutralization reduction Cr (VI) ot Cr (III) and hydroxide precipitation of some heavy metals from synthetic and industrial wastewater of some activities, such as electroplating. We used mixed culture of sulfate reducing bacteria (sludge blanket) in the bioreactors for sulfide precipitation of metals such as Pb, Zn, Ni, Cd, Hg. and Cu. This process has several advantages over chemical treatment. This process are simple developed commercially practical because of low operation cost. Chemical process isn’t commercial because of high operation cost and difficulty of treatment arises by generation of metal hydroxid in this process. Therefor, chemical methods aren’t enough efficient for removing of heavy metals from wastewater, because of different pH for precipitation of different hydroxide.