Influential factors of formation kinetics of flocs produced by water treatment coagulants  

作　　者：Chunde Wu Lin Wang Bing Hu Jian Ye 

机构地区：[1]College of Environmental Science and Engineering,South China University of Technology [2]The Key Laboratory of Pollution Control and Ecosystem Restoration in Industry Clusters of Ministry of Education [3]The Key Laboratory of Environmental Protection and Eco-Remediation of Guangdong Regular Higher Education Institutions

出　　处：《Journal of Environmental Sciences》2013年第5期1015-1022,共8页环境科学学报（英文版）

基　　金：supported by the National Natural Science Foundation of China (No. 51078148,41173103)

摘　　要：The growth rate and size of floc formation is of great importance in water treatment especially in coagulation process.The floc formation kinetics and the coagulation efficiency of synthetic water were investigated by using an on-line continuous optical photometric dispersion analyze and the analysis of water quality.Experimental conditions such as alum dosage,pH value for coagulation,stirring intensity and initial turbidity were extensively examined.The photometric dispersion analyze results showed that coagulation of kaolin suspensions with two coagulants（alum and polyaluminium chloride） could be taken as a two-phase process：slow and rapid growth periods.Operating conditions with higher coagulant doses,appropriate pH and average shear rate might be particularly advantageous.The rate of overall floc growth was mainly determined by a combination of hydraulic and water quality conditions such as pH and turbidity.The measurement of zeta potential indicates that polyaluminium chloride exhibited higher charge-neutralizing ability than alum and achieved lower turbidities than alum for equivalent Al dosages.Under the same operating conditions,the alum showed a higher grow rate,but with smaller floc size.The growth rate and size of floc formation is of great importance in water treatment especially in coagulation process.The floc formation kinetics and the coagulation efficiency of synthetic water were investigated by using an on-line continuous optical photometric dispersion analyze and the analysis of water quality.Experimental conditions such as alum dosage,pH value for coagulation,stirring intensity and initial turbidity were extensively examined.The photometric dispersion analyze results showed that coagulation of kaolin suspensions with two coagulants（alum and polyaluminium chloride） could be taken as a two-phase process：slow and rapid growth periods.Operating conditions with higher coagulant doses,appropriate pH and average shear rate might be particularly advantageous.The rate of overall floc growth was mainly determined by a combination of hydraulic and water quality conditions such as pH and turbidity.The measurement of zeta potential indicates that polyaluminium chloride exhibited higher charge-neutralizing ability than alum and achieved lower turbidities than alum for equivalent Al dosages.Under the same operating conditions,the alum showed a higher grow rate,but with smaller floc size.

关 键 词：FLOC flocculation index growth rate KINETICS 

分 类 号：X703[环境科学与工程—环境工程]