title: Effect of deflocculation on the efficiency of sludge reduction by Fenton process.
abstract: A novel approach to improve the efficiency of Fenton treatment for sludge reduction through the implication of a deflocculating agent citric acid, for the exclusion of extracellular polymeric substances (EPS) from waste-activated sludge (WAS), was investigated. Deflocculation was achieved with 0.06 g/g suspended solids (SS) of citric acid dosage. Fenton optimization studies using response surface methodology (RSM) revealed that 0.5 and 0.0055 g/g SS were the optimal dosages of H2O2 and Fe(2+). The addition of a cation-binding agent set the pH value of sludge to 5 which did not affect the Fenton efficiency. The results presented in this study shows the advantage of deflocculating the sludge as SS and volatile suspended solids (VSS) reductions were found to be higher in the deflocculated (53 and 63 %, respectively) than in the flocculated (22 and 34 %, respectively) sludges. Kinetic investigation of the treatment showed that the rate of the reaction was four times higher in the deflocculated sludge than control. The methodology reported in this manuscript was successfully applied to a real case were the deflocculated mediated Fenton process reduced the sludge disposal cost from 297.8 to 61.9 US dollars/ton of sludge.
authors.affiliation: Department of Civil Engineering, Regional Centre of Anna University, Tirunelveli, India.
authors.forename: V
authors.initials: V
authors.lastname: Amudha
authors.affiliation: Department of Civil Engineering, Regional Centre of Anna University, Tirunelveli, India.
authors.forename: S
authors.initials: S
authors.lastname: Kavitha
authors.affiliation: School of Pharmacy and Life Sciences, Robert Gordon University, Garthdee Road, Aberdeen, AB10 7GJ, UK.
authors.forename: C
authors.initials: C
authors.lastname: Fernandez
authors.affiliation: Department of Civil Engineering, Regional Centre of Anna University, Tirunelveli, India.
authors.forename: S
authors.initials: S
authors.lastname: Adishkumar
authors.affiliation: Department of Civil Engineering, Regional Centre of Anna University, Tirunelveli, India. rajeshces@gmail.com.
authors.forename: J Rajesh
authors.initials: JR
authors.lastname: Banu
mesh_terms: D019343:Citric Acid / Q000737:chemistry*; D005427:Flocculation; D006861:Hydrogen Peroxide / Q000737:chemistry*; D007700:Kinetics; D012722:Sewage / Q000032:analysis*; D014865:Waste Disposal, Fluid / Q000379:methods*
chemical_list: D012722:Sewage; D019343:Citric Acid; D006861:Hydrogen Peroxide
keywords: Citric acid; Deflocculation; Extrapolymeric substances; Fenton reaction; Sludge reduction; Waste-activated sludge