New Seaweeds Coagulant Aids on Coagulation Performance and Floc Characteristics of Ferric Chloride Coagulant in Kaolin-humic Acid Solution Treatment

Using coagulant aid to increase the organics removal is one of the main methods to improve the coagulation effect. The development of new coagulant aids has vital significance to water supply and sewage treatment. This paper develops two kinds of new seaweeds coagulant aids-Enteromorpha extract (EE) and sodium alginate (SA), and then the two coagulant aids were used together with ferric chloride (FC) in humic acid - kaolin water sample. The coagulation aid effect of BE and SA were studied through the comparation of coagulation effects before and after the application of them. Meanwhile, the growth, breakage and regrowth of flocs were investigated by use of a laser diffraction particle sizing device. The experimental results showed that Ee had significant coagulant aid effect while the aid role of SA was not obvious, but when used together with PC, flocs showed larger particle sizes and growth rates no matter which coagulant aid was selected. Meanwhile the strength and recovery ability of flocs showed a corresponding increase.