PAC和PDM联用对湘江原水藻类去除的生产性试验

Productive Test of Algae Removal from Raw Water of Xiangjiang River by Combined Chemical Dosing of PAC and PDM

湘江水源长沙段每年均出现周期性藻类暴发。为解决水厂使用聚合氯化铝(PAC)对含藻水处理效果不佳的问题,研究PAC和聚二甲基二烯丙基氯化铵(PDM)联合投加对藻类的去除效果。研究结果表明,PAC和PDM联合投加后,絮凝反应池末端可明显观察到絮体粒径变大,沉淀池出水清澈,大大减缓了斜管沉淀池蜂窝的堵塞程度。通过在水厂开展生产性试验,得到针对试验期间水质的药剂建议投加量为12 mg/L PAC+0.5 mg/L PDM。在此条件下沉淀池出水藻类、浑浊度、OD_(680)、UV_(254)、COD_(Mn)去除率分别为97.71%、91.60%、97.79%、61.74%、38.04%,相对于对照组分别提高了18.04%、16.20%、21.32%、19.19%、19.22%。PAC和PDM联合投加方法对藻类、浑浊度、有机物的去除效果显著,可为高藻期间水厂藻类去除提供参考。

The Changsha section of the Xiangjiang River has periodic algae outbreaks every year.In order to solve the problem of poor treatment of algae-containing water by polyaluminum chloride(PAC)in water treatment plants(WTP),the effect of combined dosing of PAC and polydimethyldiallyl ammonium chloride(PDM)on algae removal was studied.Results showed that,after the combined dosing of PAC and PDM,the flocs size increased obviously at the end of the flocculation reaction tank.The treated water of sedimentation tank was clear,which greatly reduced the blockage of the honeycomb of inclined tube sedimentation tank.Through the optimization of the jar tests and the production tests,the recommended dosages for the water quality during the test period were 12 mg/L PAC+0.5 mg/L PDM.Under these conditions,the removal rates of algae,turbidity,OD_(680),UV_(254),and COD_(Mn)in the test group were 97.71%,91.60%,97.79%,61.74%and 38.04%,respectively,which were increased by 18.04%,16.20%,21.32%,19.19%and 19.22%,compared to the control group.Results demonstrated that this method had a significant effect on the removal of algae,turbidity and organic matter,which could provide a reference for algae removal in water plant during high algae periods.