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Metallic wastewater treatment by sulfate reduction using anaerobic rotating biological contactor reactor under high metal loading conditions

Kiran, Mothe Gopi, Pakshirajan, Kannan, Das, Gopal
Frontiers of environmental science & engineering 2018 v.12 no.4 pp. 12
biofilm, bioreactors, cadmium, copper, energy-dispersive X-ray analysis, experimental design, heavy metals, iron, lead, nickel, scanning electron microscopy, sulfates, sulfides, wastewater, wastewater treatment, zinc
This study was aimed at investigating the performance of anaerobic rotating biological contactor reactor treating synthetic wastewater containing a mixture of heavy metals under sulfate reducing condition. Statistically valid factorial design of experiments was carried out to understand the dynamics of metal removal using this bioreactor system. Copper removal was maximum (>98%), followed by other heavy metals at their respective low inlet concentrations. Metal loading rates less than 3.7 mg/L∙h in case of Cu(II); less than 1.69 mg/L∙h for Ni(II), Pb(II), Zn(II), Fe(III) and Cd(II) are favorable to the performance of the An-RBC reactor. Removal efficiency of the heavy metals from mixture depended on the metal species and their inlet loading concentrations. Analysis of metal precipitates formed in the sulfidogenic bioreactor by field emission scanning electron microscopy along with energy dispersive X-ray spectroscopy (FESEM-EDX) confirmed metal sulfide precipitation by SRB. All these results clearly revealed that the attached growth biofilm bioreactor is well suited for heavy metal removal from complex mixture.