混凝沉淀过程中铝系混凝剂的形态转化规律

Transformation rule of aluminum form of Al-based coagulants in coagulation and sedimentation process.

研究了模拟配水中硫酸铝和氯化铝2种传统铝凝聚剂和2种聚合氯化铝(PAC)絮凝剂在混凝过程中的形态转化规律以及原水浊度和溶解性有机碳(DOC)对残余铝形态分布的影响.结果表明,在低浊体系中,投加铝系混凝剂是导致出水余铝升高的主要原因;但在高浊体系中,铝系混凝剂,尤其是聚合铝具有一定的除铝功能;混凝沉淀过程中传统铝凝聚剂的残余铝总量明显高于聚合铝混凝剂的残余铝总量;聚合铝混凝剂的残余铝全部为悬浮态铝,传统铝混凝剂的残余铝中还存在着胶体态铝和溶解态铝.原水浊度和DOC浓度增加,会提高残余铝中胶体态铝和溶解态铝的含量.

The transformation rule of two kinds of traditional aluminum coagulants in simulated water including aluminum sulfate and aluminum chloride, and two kinds of polymeric aluminum chloride (PAC) flocculants in coagulation process and also the influences of turbidity and dissolved organic carbon (DOC) in raw water on the form distribution of residual aluminum were studied. In the system of low turbidity, addition of Al-based coagulants was the main cause leading to increase of residual aluminum in effluent water, while in the system of high turbidity, the Al-based coagulants, especially polymeric aluminum, possessed definite function to remove aluminum. In the coagulation and sedimentation processes, the total residual aluminum amount of traditional aluminum coagulants was higher obviously than that of polymeric aluminum coagulants. All the residual aluminum of polymeric aluminum was suspended aluminum. There existed also colloidal aluminum and soluble aluminum in the residual aluminum of traditional coagulants. The contents of colloidal aluminum and soluble aluminum in residual aluminum could be enhanced by the increate of turbidity and the concentration of DOC of raw water.