Influence factors for treating coking wastewater by ultrasonic wave

The treatment of coking wastewater was researched by ultrasonic wave. The influences of irradiation time, ultrasonic power, initial pH value of coking wastewater, initial concentrations of chemical oxygen demand (COD_Cr) and ammonium (NH₄⁺), and dissolved gas on the removal of COD_Cr and NH₄⁺ were investigated systematically. The ultrasonic treatments of coking wastewater combined with oxidants were comparatively analyzed. The results show that the ultrasonic treatment combined with H₂O₂ or Fenton reagent had a synergetic effect, and then the removal rates of COD_Cr, and NH₄⁺ greatly increase. The order of removal rate is the following:ultrasonic treatment + Fenton 〉 ultrasonic treatment + H₂O₂ 〉 Fenton 〉 ultrasonic treatment 〉 H₂O₂. According to the analysis results of GC-MS, the removal process of COD_Cr and NH₄⁺ was preliminary studied. It is found that the proportions of non-biodegradation organisms, such as naphthalene, anthracene and quinoline, obviously decreased in treated coking wastewater.