印染废水水解酸化过程中的问题诊断及解决方案

Problem diagnosis and solution development during hydrolysis acidification of printing and dyeing wastewater

针对某印染废水处理厂水解酸化段运行异常的问题,依托水解酸化序批式反应器(SBR)开展问题诊断及解决方案研究。通过历时取样实验确认了水解酸化过程中挥发性脂肪酸(VFAs)不升反降和有机氮氨化率偏低的问题;通过控制低pH(pH=5)运行实验清除消耗VFAs的微生物,实现VFAs累积;通过非控制pH运行实验实现VFAs的累积和有机氮氨化率的提高;通过历时取样实验确定水解酸化的最佳反应时间为10 h。长期运行实验显示,在平均进水COD为1 085 mg/L、氨氮为9.5 mg/L、VFAs为43.7 mg/L的条件下,水解酸化SBR平均出水COD为736 mg/L、氨氮为19.5 mg/L、VFAs为64.2 mg/L,为后续生物除碳脱氮奠定了良好基础。基于小试研究,该厂成功实施了水解酸化池短时酸化并适当排泥的解决方案。

In order to solve the abnormal problems of hydrolysis acidification stage in a printing and dyeing wastewater treatment plant,the problem diagnosis and solution development were conducted via a hydrolysis acidification sequencing batch reactor(SBR). Sampling tests with reaction time demonstrated that the volatile fatty acids(VFAs)did not increase but decreased and the ammonification ratio of organic nitrogen was low in hydrolysis acidification SBR. The operation with low pH(pH=5)control successfully eliminated the microorganism consuming VFAs and achieved VFAs accumulation in SBR. Then,the operation without pH control successfully achieved VFAs accumulation and improved ammonification ratio of organic nitrogen in SBR. Sampling tests with reaction time further determined the optimal reaction time of 10 h.Long term operation showed that when the average COD,ammonia nitrogen and VFAs of the influent were 1 085 mg/L,9.5 mg/L and 43.7 mg/L respectively,the average COD,ammonia nitrogen and VFAs of the SBR effluent were 736 mg/L,19.5 mg/L and 64.2 mg/L respectively,favoring for the subsequent biological carbon and nitrogen removal. Based on the pilot study,the solution of short-term acidification and appropriate sludge discharge from the hydrolysis acidification tank of the plant was successfully conducted.