title: Effective removal of contaminants in landfill leachate membrane concentrates by coagulation.
abstract: Leachate membrane concentrates containing high concentrations of organics and trace toxic compounds pose a major threat to the environment, and their treatment is an urgent issue. In this work, various coagulants were used to treat leachate membrane concentrates. Appropriate pH values for treatments with FeCl2, FeSO4, polyaluminum chloride, and FeCl3were 3, 5, 5, and 4, respectively. FeCl3achieved the highest total organic carbon (TOC) removal efficiency. The effect of the various anions in ferric coagulants [FeCl3, Fe2(SO4)3, and Fe(NO3)3] on the TOC removal efficiency was negligible. The main organics remaining in the leachate membrane concentrates after coagulation were humic and fulvic acids. The conditions for coagulation with FeCl3were optimized using the response surface method (RSM). The highest TOC, chemical oxygen demand (COD), and chromaticity reduction efficiencies, 81%, 82%, and 97%, respectively, were achieved at pH 4 using FeCl3(5 g L-1) and polyacrylamide (PAM; 0.07 g L-1). The COD of leachate membrane concentrates was reduced from 4000 to 718 mg L-1. The mole ratio of removed COD and Fe(III) (2.4 mol) at 5 g L-1FeCl3(pH 4, PAM 0.07 g L-1) was lower than that (3.8 mol) at 3 g L-1FeCl3(pH 4, PAM 0.07 g L-1); based on the cost and COD removal efficiency, the latter conditions were the best choice. Our work provides guidelines for the treatment of leachate membrane concentrates in engineering.
authors.affiliation: School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310012, China; Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling, Hangzhou 310012, China.
authors.forename: Yuyang
authors.initials: Y
authors.lastname: Long
authors.affiliation: School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310012, China; Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling, Hangzhou 310012, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Xu
authors.affiliation: School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310012, China; Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling, Hangzhou 310012, China.
authors.forename: Dongsheng
authors.initials: D
authors.lastname: Shen
authors.affiliation: Zhejiang Zone-King Environmental Science and Technology Co., Ltd., 7F Zhejiang Sanli Times Square, No. 536 Shaoxin Road, Hangzhou 310013, China.
authors.forename: Yao
authors.initials: Y
authors.lastname: Du
authors.affiliation: School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310012, China; Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling, Hangzhou 310012, China. Electronic address: fenghuajun@mail.zjgsu.edu.cn.
authors.forename: Huajun
authors.initials: H
authors.lastname: Feng
mesh_terms: D000536:Aluminum Hydroxide / Q000737:chemistry*; D057919:Biological Oxygen Demand Analysis; D002681:China; D005290:Ferric Compounds / Q000737:chemistry*; D005374:Filtration; D005427:Flocculation; D006812:Humic Substances / Q000032:analysis; D008567:Membranes, Artificial; D014874:Water Pollutants, Chemical / Q000032:analysis*; D018508:Water Purification / Q000379:methods*
chemical_list: D005290:Ferric Compounds; D006812:Humic Substances; D008567:Membranes, Artificial; D014874:Water Pollutants, Chemical; C016213:aluminum oxychloride; D000536:Aluminum Hydroxide
keywords: Anion effect; Coagulation; Humic acid; Leachate membrane concentrates; Organic matter; TOC removal efficiency