Evaluation of nitrogen, phosphorus and heavy metals removal from wastewater by Rhodobacter Blasticus

The potential for the removal of nitrogen, phosphorus, and heavy metals such as copper and nickel by Rhodobacter blasticus known as purple non-sulfur bacteria was evaluated in this study. In addition, the resistance of R. blasticus to two heavy metals and the effects of these metals on its cell morphology were investigated. The heavy metal adsorption characteristics by R. blasticus were confirmed using Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy (SEM-EDX) and Fourier Transform Infrared Spectroscopy (FT-IR). The nitrogen and phosphorus removal efficiencies of R. blasticus decreased as the concentration of nitrogen and phosphorus increased from 50 to 500 mg/L. The resistance, based on the minimum inhibitory concentration of R. blasticus growing under aerobic-light conditions, was found to be in the order of Ni2+ > Cu2+. SEM analysis revealed that copper ions altered the morphology of R. blasticus, while nickel treatment did not differ from the control group. Futhermore, this study confirmed that the removal efficiencies for Cu(2+ )and Ni2+ by R. blasticus were 53 +/- 0.02% and 55 +/- 0.02%, respectively. The surface of bacterial cells where heavy metals were absorbed was also confirmed by SEM-EDX. According to the FT-IR analysis results, the increased transmittance (%) after heavy metal adsorption indicates that these heavy metals were absorbed by the functional groups on the cell surface of R. blasticus.