低温低浊黄河原水对水厂沉淀池出水铝离子的影响因素

Influencing Factors of Low Temperature and Low Turbidity of Yellow River Raw Water on Aluminum Concentration in Sedimented Water of WTP

针对冬季原水呈低温低浊特点的黄河地表水厂铝离子难以处理、沉淀池出水铝离子含量偏高的问题,通过去除饮用水中铝的相关试验,探究了水厂沉后水中铝离子含量的影响因素和控制条件。结果表明,在原水低温低浊条件下,原水碱度、pH、混凝剂投加量及盐基度、助凝剂投加影响沉后水中铝离子含量,额外碱度、中性的pH、高盐基度混凝剂、助凝剂有利于沉后水中余铝的控制。预氧化可进一步去除水中的铝离子,其中臭氧对余铝的控制效果最佳。沉后水余铝与余浊的关系为正相关,浑浊度可一定程度反映余铝含量,沉后水中余铝主要以溶解态有机铝为主。

The raw water of Yellow River water treatment plant(WTP)is characterized by low temperature and low turbidity in winter,which leads to high aluminum concentration in the outflow of sedimentation tank.In this study,the influencing factors and control methods of aluminum concentration in precipitated water of the WTP were studied.Results showed that the aluminum concentration in the precipitated water was affected by the alkalinity and pH value of raw water,coagulant dosage and salinity,coagulant aid.The residual aluminum in the precipitated water could be controlled by adding alkalinity,adjusting pH value,adding coagulant aid and increasing coagulant basicity.The aluminum concentration in the precipitated water could be further reduced through the pre-oxidation process,in which the effect of ozone pre-oxidation was the best.The turbidity of the precipitated water could characterize the residual aluminum concentration,and the residual aluminum was mainly dissolved organic bound.