Efficient advanced treatment of coking wastewater using O3/H2O2/Fe-shavings process

Catalytic oxidation is widely used in the treatment of refractory wastewater. However, catalytic oxidation has some problems such as high cost and limited production of radicals. To improve these, in this study, a new process of O3/H2O2/Fe-shavings which coupled catalytic ozonation and Fenton-like oxidation with Fe-shaving wastes reused, was used in the treatment of coking wastewater secondary biochemical effluent (CWSBE). The effects of the environmental conditions on the degradation of CWSBE were studied and the response surface method was used to optimise the parameters. The performances in organic pollutant removal from CWSBE were systematically analysed by a couple of methods such as gas chromatography mass spectrometry and three-dimensional fluorescence. The results showed that macromolecular organics were degraded into small molecules pollutants after treatment by the O3/H2O2/Fe-shavings process. At an ozone concentration of 27.5 mg/L, with the hydrogen peroxide concentration being 10.7 mmol/L, the reaction time 60 min, the initial pH value 3.6, and the pump speed 150 rpm, the COD removal degradation efficiency was 77.5%, and the effluent COD met relevant wastewater discharge standards in China (GB 16171-2012). The mechanism research showed that·OH plays an important role in the degradation of organic pollutants.