title: Treatment of nanofiltration concentrates of mature landfill leachate by a coupled process of coagulation and internal micro-electrolysis adding hydrogen peroxide.
abstract: In this study, a coupled process of coagulation and aerated internal micro-electrolysis (IME) with the in situ addition of hydrogen peroxide (H2O2) was investigated for the treatment of nanofiltration (NF) concentrate from mature landfill leachate. The acceptable operating conditions were determined as follows: initial pH 4, polymeric aluminium chloride dosage of 525 mg-Al2O3/L in the coagulation process, H2O2 dosage of 0.75 mM and an hydraulic retention time of 2 h in an aerated IME reactor. As a result, the removal efficiencies for chemical oxygen demand (COD), total organic carbon, UV254 and colour were 79.2%, 79.6%, 81.8% and 90.8%, respectively. In addition, the ratio of biochemical oxygen demand (BOD5)/COD in the final effluent increased from 0.03 to 0.31, and that of E2/E4 from 12.4 to 38.5, respectively. The results indicate that the combined process is an effective and economical way to remove organic matters and to improve the biodegradability of the NF concentrate. Coagulation process reduces the adverse impact of high-molecular-weight organic matters such as humic acids, on the aerated IME process. A proper addition of H2O2 in the aerated IME can promote the corrosion of solid iron (Fe2+/Fe3+) and cause a likely domino effect in the enhancement of removal efficiencies.
authors.affiliation: a Institute of Environmental Science and Engineering , Hangzhou Dianzi University , Hangzhou 310018 , People's Republic of China.
authors.forename: Jingang
authors.initials: J
authors.lastname: Huang
authors.forename: Jianjun
authors.initials: J
authors.lastname: Chen
authors.forename: Zhengmiao
authors.initials: Z
authors.lastname: Xie
authors.forename: Xiaojun
authors.initials: X
authors.lastname: Xu
mesh_terms: D000077410:Aluminum Chloride; D017607:Aluminum Compounds; D002712:Chlorides; D004572:Electrolysis; D006861:Hydrogen Peroxide; D006863:Hydrogen-Ion Concentration; D014865:Waste Disposal, Fluid / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000737:chemistry*
chemical_list: D017607:Aluminum Compounds; D002712:Chlorides; D014874:Water Pollutants, Chemical; D000077410:Aluminum Chloride; D006861:Hydrogen Peroxide
keywords: biodegradability; coagulation; internal micro-electrolysis (IME); mature landfill leachate; nanofiltration (NF) concentrate