title: A comparative study on the efficiency of ozonation and coagulation-flocculation as pretreatment to activated carbon adsorption of biologically stabilized landfill leachate.
abstract: The present work investigates the potential of coagulation-flocculation and ozonation to pretreat biologically stabilized landfill leachate before granular activated carbon (GAC) adsorption. Both iron (III) chloride (FeCl3) and polyaluminium chloride (PACl) are investigated as coagulants. Better organic matter removal is observed when leachate was treated with FeCl3. At a dose of 1mg FeCl3/mg CODo (CODo: initial COD content), the COD and α254 removal was 66% and 88%, respectively. Dosing 1mg PACl/mg CODo resulted in 44% COD and 72% α254 removal. The settle-ability of sludge generated by PACl leveled off at 252mL/g, while a better settle-ability of 154mL/g was obtained for FeCl3 after dosing 1mg coagulant/mg CODo. For ozonation, the percentage of COD and α254 removal increased as the initial COD concentration decreased. Respectively 44% COD and 77% α254 removal was observed at 112mg COD/L compared to 5% COD and 26% α254 removal at 1846mg COD/L. Subsequent activated carbon adsorption of ozonated, coagulated and untreated leachate resulted in 77%, 53% and 8% total COD removal after treatment of 6 bed volumes. Clearly showing the benefit of treating the leachate before GAC adsorption. Mathematical modeling of the experimental GAC adsorption data with Thomas and Yoon-Nelson models show that ozonation increases the adsorption capacity and breakthrough time of GAC by a factor of 2.5 compared to coagulation-flocculation.
authors.affiliation: LIWET, Department of Industrial Biological Sciences, Ghent University, Campus Kortrijk, Graaf Karel de Goedelaan 5, B-8500 Kortrijk, Belgium; EnVOC, Department of Sustainable Organic Chemistry and Technology, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium; Kenya Industrial Research and Development Institute (KIRDI), P.O. Box 30650-00100, Nairobi, Kenya.
authors.forename: Violet
authors.initials: V
authors.lastname: Oloibiri
authors.affiliation: LIWET, Department of Industrial Biological Sciences, Ghent University, Campus Kortrijk, Graaf Karel de Goedelaan 5, B-8500 Kortrijk, Belgium; EnVOC, Department of Sustainable Organic Chemistry and Technology, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium.
authors.forename: Innocent
authors.initials: I
authors.lastname: Ufomba
authors.affiliation: LIWET, Department of Industrial Biological Sciences, Ghent University, Campus Kortrijk, Graaf Karel de Goedelaan 5, B-8500 Kortrijk, Belgium; BIOMATH, Department of Mathematical Modeling, Statistics and Bioinformatics, Ghent University, Gent, Belgium.
authors.forename: Michael
authors.initials: M
authors.lastname: Chys
authors.affiliation: LIWET, Department of Industrial Biological Sciences, Ghent University, Campus Kortrijk, Graaf Karel de Goedelaan 5, B-8500 Kortrijk, Belgium; BIOMATH, Department of Mathematical Modeling, Statistics and Bioinformatics, Ghent University, Gent, Belgium.
authors.forename: Wim T M
authors.initials: WT
authors.lastname: Audenaert
authors.affiliation: EnVOC, Department of Sustainable Organic Chemistry and Technology, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium.
authors.forename: Kristof
authors.initials: K
authors.lastname: Demeestere
authors.affiliation: LIWET, Department of Industrial Biological Sciences, Ghent University, Campus Kortrijk, Graaf Karel de Goedelaan 5, B-8500 Kortrijk, Belgium; BIOMATH, Department of Mathematical Modeling, Statistics and Bioinformatics, Ghent University, Gent, Belgium. Electronic address: stijn.vanhulle@ugent.be.
authors.forename: Stijn W H
authors.initials: SW
authors.lastname: Van Hulle
mesh_terms: D000327:Adsorption; D000536:Aluminum Hydroxide / Q000737:chemistry; D001530:Belgium; D057919:Biological Oxygen Demand Analysis; D002606:Charcoal; D005296:Ferrous Compounds / Q000737:chemistry; D005427:Flocculation; D010126:Ozone / Q000737:chemistry*; D018505:Waste Management / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification / Q000379:methods
chemical_list: D005296:Ferrous Compounds; D014874:Water Pollutants, Chemical; C016213:aluminum oxychloride; D002606:Charcoal; D000536:Aluminum Hydroxide; D010126:Ozone; C029451:ferrous chloride
keywords: Adsorption; Coagulation–flocculation; Granular activated carbon; Landfill leachate; Ozonation