ABSTRACT
Background: in this study, ferrate [VI] and ultraviolet [UV] radiation were employed to remove hydrogen sulfide from municipal wastewater resulting in a reduction in chemical oxygen demand [COD]. Although ferrate [VI] and UV have been used individually for the removal of a few pollutants from urban and industrial wastewater, there exists no study to investigate the effectiveness of simultaneous utilization of both methods for the removal of hydrogen sulfide and reducing COD
Methods: this study aims to compare the application of UV, ferrate [VI] and UV/ferrate [VI] for the removal of hydrogen sulfide and COD from municipal wastewater in batch mode. Moreover, the effect of many parameters such as ferrate [VI] concentration, temperature, hydraulic retention time [HRT] and pH on ferrate [VI] oxidation power, were investigated
Results: the results of this study demonstrated that for pH less than 2, higher pollutant removal efficiency was obtained. COD removal efficiency could increase up to 68% by adding 1.68 mg/L of ferrate [VI], almost 100% of hydrogen sulfide was removed by the same concentration of ferrate [VI]. Both hydrogen sulfide and COD removal efficiencies increased as temperature increased to 50degreeC; nevertheless, further increase in temperature had negative effect on the removal efficiency. The use of UV/ferrate [VI] increased the removal efficiency of both hydrogen sulfide and COD when compared with the use of UV and ferrate [VI] individually. UV method was not effective in the removal of hydrogen sulfide
Conclusion: the research findings shed new light on wastewater treatment systems employing UV/ ferrate [VI] to decrease both the hydrogen sulfide and COD of municipal wastewater. This new findings will assist in the inaccurate design and effective operation of such systems which can be employed to maintain or improve environmental quality
ABSTRACT
Background: The aim of this study is to compare UV, ferrate [VI] and UV/ferrate [VI] methods for removal of hydrogen sulfide and chemical oxygen demand [COD] from municipal wastewater under a continuous condition
Methods: The experiment was divided into three parts: 1] pollutants removal by using ferrate [VI] alone; 2] pollutants removal using UV alone; 3] pollutants removal using a combination of UV/ferrate [VI]. The electrolysis process was utilized to generate ferrate [VI]
Results: The results showed that UV had the highest pollutants removal, so that 89% and 85% of hydrogen sulfide and COD were removed from the wastewater, respectively. UV/ferrate [VI] ranked as the next most efficient method. This method removed 65% and 73% of hydrogen sulfide and COD, respectively from the wastewater
Conclusion: Using ferrate [VI] alone had the lowest pollutant removal efficiency, with 41% and 48% of hydrogen sulfide and COD removal from wastewater, respectively. UV has a higher ability to remove hydrogen sulfide and COD from wastewater, compared with UV/ferrate [VI] and ferrate [VI] alone