内电解-水解酸化-接触氧化-氧化絮凝处理印染废水研究

Treatment of dyeing wastewater by inner electrolysis-hydrolysis acidification-contact oxidation-oxidation coagulation integrated process

采用内电解—水解酸化—接触氧化—氧化絮凝处理印染废水,考察了内电解反应中进水pH、反应时间、反应温度、鲍尔环填料中铁粉与焦炭质量比(简称Fe/C)对废水COD和色度去除效果的影响;在实验所得最佳条件下,内电解反应对废水中NH3-N和TP的去除效果;水解酸化—接触氧化对内电解出水的COD和NH3-N的去除效果及反应前后的pH变化;生化出水的氧化絮凝深度处理单元中,不同组合药剂的COD去除效果。结果表明,内电解反应的最佳条件是:pH为3左右、反应时间为120 min、15～20℃、Fe/C为2,内电解对印染废水的COD、色度、TP的去除效果很好,废水的可生化性也得到提高;内电解预处理后的印染废水经过水解酸化阶段后,COD去除率在35%左右,而NH3-N反而小幅增加,pH降低了0.3左右,可生化性进一步提高;在接触氧化阶段,COD去除率达70%左右,NH3-N去除率在95%以上,出水的COD稳定在148～180 mg/L;次氯酸钙与自制改性铝盐絮凝剂混合物(150 mg/L)+复合絮凝剂(150 mg/L)+3滴0.5%(质量分数)聚丙烯酰胺(PAM)组合药剂适宜作生化出水的氧化絮凝剂,混凝后最终出水的COD低于100 mg/L,达到《污水综合排放标准》(GB 8978—1996)的一级标准。

The inner electrolysis-hydrolysis acidification-contact oxidation-oxidation coagulation integrated process was established for treatment of the dyeing wastewater,the effect of influent pH,contacting time,temperature,Fe/C mass ratio of pall ring filler on COD and colourity removal efficiency was investigated.The performance of each unit was analyzed separately.Results showed that the optimal conditions for inner electrolysis were pH 3,reacted for 120 min,15～20 ℃ and Fe/C was 2,under these conditions,the inner electrolysis achieved perfect efficiency for COD,colourity and TP removal,the biodegradability of dyeing wastewater was greatly improved.In the next hydrolysis acidification unit,the COD removal efficiency was 35% while NH3-N slightly increased,pH was decreased by 0.3 and biodegradability of wastewater was further improved.In contact oxidation process,the effluent COD was dropped to 148-180 mg/L,the removal efficiency of COD and NH3-N was 70% and 95% respectively.The last oxidation coagulation process was applied for further treatment of effluent,after coagulation treated by the best combined reagent,the COD concentration was less than 100 mg/L,which could meet the second class discharge standard of Integrated Wastewater Discharge Standard（GB 8798—1996）.