title: Investigation of colloidal biogenic sulfur flocculation: Optimization using response surface analysis.
abstract: The colloidal properties of biogenic elemental sulfur (S(0)) cause solid-liquid separation problems, such as poor settling and membrane fouling. In this study, the separation of S(0) from bulk liquids was performed using flocculation. Polyaluminum chloride (PAC), polyacrylamide (PAM) and microbial flocculant (MBF) were compared to investigate their abilities to flocculate S(0) produced during the treatment of sulfate-containing wastewater. A novel approach with response surface methodology (RSM) was employed to evaluate the effects and interactions of flocculant dose, pH and stirring intensity, on the treatment efficiency in terms of the S(0) flocculation and the supernatant turbidity removal. The dose optimization results indicated that the S(0) flocculation efficiency decreased in the following order PAC>MBF>PAM. Optimum S(0) flocculation conditions were observed at pH4.73, a stirring speed of 129 r/min and a flocculant dose of 2.42 mg PAC/mgS. During optimum flocculation conditions, the S(0) flocculation rate reached 97.53%. Confirmation experiments demonstrated that employing PAC for S(0) flocculation is feasible and RSM is an efficient approach for optimizing the process of S(0) flocculation. The results provide basic parameters and conditions for recovering sulfur during the treatment of sulfate-laden wastewaters.
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China. Electronic address: chenfanhit@163.com.
authors.forename: Fan
authors.initials: F
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China.
authors.forename: Ye
authors.initials: Y
authors.lastname: Yuan
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China.
authors.forename: Chuan
authors.initials: C
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China.
authors.forename: Youkang
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China.
authors.forename: Wenbo
authors.initials: W
authors.lastname: Tan
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China.
authors.forename: Cong
authors.initials: C
authors.lastname: Huang
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China.
authors.forename: Xijun
authors.initials: X
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China; Key Laboratory of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, China. Electronic address: ajwang@rcees.ac.cn.
authors.forename: Aijie
authors.initials: A
authors.lastname: Wang
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry; D000536:Aluminum Hydroxide / Q000737:chemistry; D005427:Flocculation; D007220:Industrial Waste; D013455:Sulfur / Q000032:analysis* / Q000737:chemistry; D014865:Waste Disposal, Fluid / Q000379:methods*; D062065:Wastewater / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000737:chemistry; D000099166:Polyacrylamides
chemical_list: D000180:Acrylic Resins; D000536:Aluminum Hydroxide; D007220:Industrial Waste; D013455:Sulfur; D062065:Wastewater; D014874:Water Pollutants, Chemical; D000099166:Polyacrylamides; C016213:aluminum oxychloride
keywords: Elemental sulfur; Flocculation; Optimization; Response surface methodology (RSM)