慢滤-消毒对二级出水中污染物去除及影响因素

Removal of Pollutants from Secondary Effluent by Slow Filtration-disinfection and Its Influencing Factors

再生水回用是解决水资源危机的重要途径,但是城市污水厂二级出水中仍含有大量的污染物,对人们的身体健康存在着潜在威胁。为保证再生水回用的安全性,通过探究生物膜慢滤-次氯酸钠消毒组合工艺处理污水厂二级出水的方法研究了该工艺对水中的有机物和条件致病菌的去除效能,并对其影响因素进行分析。结果表明,相同滤速下,生物膜慢滤较慢滤对溶解性有机物的去除效果好,滤速为20 cm/h时对溶解性有机物的去除效果最佳;生物膜慢滤对富里酸类有机物、微生物副产物类有机物、腐殖酸类有机物的处理效果均比慢滤好;相同滤速下,生物膜慢滤对浊度的去除效果优于慢滤;在NaClO最佳投加量8.0 mg/L(以有效氯浓度计)的条件下,生物膜慢滤-NaClO消毒组合工艺对军团菌、铜绿假单胞菌均有较好的去除效果,且NaClO对于自由悬浮态条件致病菌的去除效果更优;另外,较低pH值和较高水温更有利于NaClO消毒对水中条件致病菌的去除。可见,生物膜慢滤-次氯酸钠消毒工艺可以有效控制二级出水中的有机物和条件致病菌等污染物,可以一定程度上保证再生水回用的安全性。

The reuse of reclaimed water is an important way to solve the water crisis,but the secondary effluent of urban sewage plants still contains a large amount of pollutants,which pose a potential threat to people’s health.In order to ensure the safety of reclaimed water reuse,exploring the method of biofilm slow filtration-sodium hypochlorite disinfection combined process for the treatment of secondary effluent of sewage plant was used to investigate the removal efficiency of organic matter and opportunistic pathogens in water.Analysis of influencing factors.The results show that under the same filtration rate,the biofilm slow filtration has better removal effect of dissolved organic compound(DOC)than the slow filtration,and the removal effect of dissolved organic compound is the best when the filtration rate is 20 cm/h.The treatment effect of product organic matter and humic acid organic matter is better than that of slow filtration.Under the same filtration rate,the turbidity removal effect of biomembrane slow filtration was better than that of slow filtration.The optimum dosage of NaClO is 8.0 mg/L(under the condition of effective chlorine concentration),the combined process of biofilm slow filtration-NaClO disinfection has better removal effect on Legionella and Pseudomonas aeruginosa,and NaClO has better removal effect on pathogenic bacteria in free suspension state.In addition,lower pH value and higher water temperature are more conducive to the removal of conditioned pathogens in water by NaClO disinfection.It is concluded that the biofilm slow filtration-sodium hypochlorite disinfection process can effectively control pollutants such as organic matter and opportunistic pathogens in the secondary effluent,and can ensure the safety of reclaimed water reuse to a certain extent.