title: The role of sodium alginate in improving floc size and strength and the subsequent effects on ultrafiltration membrane fouling.
abstract: BACKGROUND
  Dosing environment-friendly polymer as coagulant aids is an encouraging method in water treatment to obtain desirable floc characteristics. Sodium alginate (SA) was used as the coagulant aid for synthetic humic acid (HA) water treatment to investigate the effect on flocs characteristics and ultrafiltration (UF) membrane fouling.
  
  
  RESULTS
  When SA content was 0.3 mg L-1, the treatment of HA by polyaluminium chloride (PAC) plus SA (PAC/SA) yielded the maximum removal efficiency of 66.5%, which was higher than the maximum HA removal efficiency of PAC (58%). Moreover, the HA flocs size of PAC would grow from 269 to 367 Iim after SA was added. Strength factor and recovery factor of PAC/SA were larger than those of PAC. These resulted in the improvement in subsequent UF membrane performance. The membrane fouling decreased in the following order: the raw water > PAC coagulated water > PAC/SA coagulated water.
  
  
  CONCLUSIONS
  The study showed that the application of SA as coagulant aids resulted in larger and stronger flocs, which would improve treatment efficiency of the coagulation process. And the flocs formed by PAC/SA contributed to the restriction of the fouling of UF membrane, which would decrease the cost of advanced water treatment.
authors.affiliation: Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Jinan 250100, People's Republic of China. wangyan_sdjn@yahoo.com.cn
authors.forename: Yan
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Jinan 250100, People's Republic of China.
authors.forename: Xiangzuo
authors.initials: X
authors.lastname: Li
authors.affiliation: Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Jinan 250100, People's Republic of China.
authors.forename: Caihong
authors.initials: C
authors.lastname: Wu
authors.affiliation: Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Jinan 250100, People's Republic of China.
authors.forename: Yanxia
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Jinan 250100, People's Republic of China.
authors.forename: Bao-Yu
authors.initials: BY
authors.lastname: Gao
authors.affiliation: Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Jinan 250100, People's Republic of China.
authors.forename: Qinyan
authors.initials: Q
authors.lastname: Yue
mesh_terms: D000464:Alginates / Q000737:chemistry*; D004866:Equipment Contamination / Q000517:prevention & control*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005427:Flocculation; D020723:Glucuronic Acid / Q000737:chemistry; D006603:Hexuronic Acids / Q000737:chemistry; D006812:Humic Substances / Q000032:analysis; D008567:Membranes, Artificial; D010316:Particle Size; D014462:Ultrafiltration / Q000295:instrumentation*; D014874:Water Pollutants, Chemical / Q000737:chemistry / Q000302:isolation & purification*; D018508:Water Purification / Q000295:instrumentation*
chemical_list: D000464:Alginates; D006603:Hexuronic Acids; D006812:Humic Substances; D008567:Membranes, Artificial; D014874:Water Pollutants, Chemical; D020723:Glucuronic Acid