原水pH值升高导致出厂水余铝含量升高的应对措施

Control of Increase of Residual Aluminum in Finished Water Caused by Abnormal p H Increase in Raw Water

某水厂进入夏季以来,出厂水余铝含量上升,最高达到0.26 mg/L,超过《生活饮用水卫生标准》(GB 5749—2006)规定的限值(0.2 mg/L)。分析了出厂水余铝含量升高的原因,并考察了高锰酸钾预氧化、HCA(聚二甲基二烯丙基氯化铵)助凝、盐酸预处理、二氧化碳曝气预处理、氯化铁复配混凝多种措施降低余铝含量的效果。结果表明:水厂出厂水余铝含量升高与原水pH值升高有直接关系,氯化铁复配混凝除铝效果最明显,对铝的去除率达到80%,且实际应用性强。

The residual aluminum content in the finished water of a water plant had increased continuously in the summer,reached a maximum level of 0.26 mg/L,and exceeded the 0.2 mg/L limit specified in Standards for Drinking Water Quality(GB 5749-2006).The causes and various measures to reduce the residual aluminum content were studied.The control measures included potassium permanganate preoxidation,HCA coagulation,hydrochloric acid pretreatment,carbon dioxide aeration pretreatment,and ferric chloride compound coagulation.The results showed that the increase of residual aluminum content was directly related to the increase of pH in raw water.The ferric chloride compound coagulation method was most effective on aluminum removal,which reached 80%,and it had strong practicability.