预臭氧对混凝除藻工艺的影响

Impacts of preozonation on algae removal during coagulation

预氧化是水处理中控制微生物、消毒副产物（DBPs，DisinfectionBy-Products）及其前驱物、改善混凝及常规工艺效果的重要技术。模拟预臭氧强化混凝水处理流程，研究了臭氧预氧化、不同碱化度混凝剂混凝过程对藻类的去除过程。对预臭氧和混凝技术应用中有机物变化、DBPs产生和消除等进行了研究。结果表明：预臭氧混凝对藻类去除效果好于单独使用臭氧氧化或混凝；在混凝剂投药量较低段（0～3．0mg／L），臭氧有效提高混凝除藻效率，有效藻类计数由41．5×10^3个/mL降到4．5×10^3个/mL。高浓度（2．0—3．0mg／L）的臭氧对溶解性有机物（DOC）的去除有负面影响；但结合常规操作中预臭氧投量（0～1．Omg／L），预臭氧对混凝除藻和控制有机物有促进作用，且并不会显著造成有机物和消毒副产物升高。

Preozonation is an important technique utilized to control microbial, DBPs （Disinfection By-Products） and their precusors to improve coagulation and other traditional treatments. Algae re- movals by preozonation and coagulation using different coagulants with various B values were investi- gated, following traditional water treatment process. Change of organic matter, DBPs formation and re- moval during the preozonation and enhanced coagulation treatments were studied Results show that preozonation combined with enhanced coagulation has better removal of algae than either ozonation or coagulation singlely. Preozonation improved algae removal efficiently at lower coagulant dosage from 0mg/L to 3.0mg/L, and the algae was reduced from 41.5×10^3 cell/mL to 4.5×10^3 cell/mL. Preozonation with relatively high dose （2.0~3.0mg/L）would impair DOC removal although, preozonation at nomal dosage（ 0~l.0mg/L ）showed enhancement of both algae removal and DOC control, and would not cause the release of DOC and increase of DBPs.