title: Pretreatment of concentrated leachate by the combination of coagulation and catalytic ozonation with Ce/AC catalyst.
abstract: A raw concentrated leachate produced from membrane bioreactor-nanofiltration (MBR-NF) was taken from Chengdu Chang'an Waste Landfill Site, China. The major fraction of this concentrated leachate was large refractory humic substances. A coagulation-ozonation process was applied to treat this leachate, aiming at enhancing chemical oxygen demand (COD) removal efficiency and increasing its biodegradability. Meanwhile the molecular size distribution of the leachate, before and after coagulation and ozonation treatment, was analyzed by using ultrafiltration membrane separation. Coagulation pretreatment effectively removed varieties of large molecules in the raw concentrated leachate. The addition of Ce/AC greatly improved the oxidative ability of O3 in COD removal in the ozonation of coagulated leachate. The biochemical oxygen demand (BOD5)/COD ratio increased from 0.011 for the untreated concentrated leachate to 0.30 for the effluent of the coagulation-catalytic ozonation process, which indicated that a subsequent biological treatment could be readily conducted. The stability test demonstrated that the Ce/AC catalyst was effective and stable in the catalytic ozonation process. According to the results of molecular size distribution analysis, a direct correlation was observed between the increase of BOD5/COD and the decrease of apparent molecular weight.
authors.affiliation: College of Material and Chemical Engineering, Tongren University, Tongren 554300, China E-mail: qinhangdao@126.com.
authors.forename: Hangdao
authors.initials: H
authors.lastname: Qin
authors.affiliation: Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu 610041, China.
authors.forename: Honglin
authors.initials: H
authors.lastname: Chen
mesh_terms: D057919:Biological Oxygen Demand Analysis; D019149:Bioreactors; D002384:Catalysis; D002681:China; D010084:Oxidation-Reduction; D010126:Ozone / Q000737:chemistry*; D012037:Refuse Disposal / Q000379:methods*; D014462:Ultrafiltration; D064091:Waste Disposal Facilities; D014874:Water Pollutants, Chemical / Q000737:chemistry*
chemical_list: D014874:Water Pollutants, Chemical; D010126:Ozone