title: Treatment of hazardous landfill leachate using Fenton process followed by a combined (UASB/DHS) system.
abstract: Fenton process for pre-treatment of hazardous landfill leachate (HLL) was investigated. Total, particulate and soluble chemical oxygen demand (CODt, CODp and CODs) removal efficiency amounted to 67%, 47% and 64%, respectively, at pH value of 3.5, molar ratio (H2O2/Fe(2+)) of 5, H2O2 dosage of 25 ml/L and contact time of 15 min. Various treatment scenarios were attempted and focused on studying the effect of pre-catalytic oxidation process on the performance of up-flow anaerobic sludge blanket (UASB), UASB/down-flow hanging sponge (DHS) and DHS system. The results obtained indicated that pre-catalytic oxidation process improved the CODt removal efficiency in the UASB reactor by a value of 51.4%. Overall removal efficiencies of CODt, CODs and CODp were 80 ± 6%, 80 ± 7% and 78 ± 16% for UASB/DHS treating pre-catalytic oxidation effluent, respectively. The removal efficiencies of CODt, CODs and CODp were, respectively, decreased to 54 ± 2%, 49 ± 2% and 71 ± 16% for UASB/DHS system without pre-treatment. However, the results for the combined process (UASB/DHS) system is almost similar to those obtained for UASB reactor treating pre-catalytic oxidation effluent. The DHS system achieved average removal efficiencies of 52 ± 4% for CODt, 51 ± 4% for CODs and 52 ± 15% for CODp. A higher COD fractions removal was obtained when HLL was pre-treated by Fenton reagent. The combined processes provided a removal efficiency of 85 ± 1% for CODt, 85 ± 1% for CODs and 83 ± 8% for CODp. The DHS system is not only effective for organics degradation but also for ammonia oxidation. Almost complete ammonia (NH4-N) removal (92 ± 3.6%) was occurred and the nitrate production amounted to 37 ± 6 mg/L in the treated effluent. This study strongly recommends applying Fenton process followed by DHS system for treatment of HLL.
authors.affiliation: Environmental Engineering Department, Egypt-Japan University of Science and Technology (E-JUST), PO Box 179, 21934 New Borg El Arab City, Alexandria, Egypt E-mail: sherif.ismail@ejust.edu.eg.
authors.forename: Sherif
authors.initials: S
authors.lastname: Ismail
authors.affiliation: Environmental Engineering Department, Egypt-Japan University of Science and Technology (E-JUST), PO Box 179, 21934 New Borg El Arab City, Alexandria, Egypt E-mail: sherif.ismail@ejust.edu.eg.
authors.forename: Ahmed
authors.initials: A
authors.lastname: Tawfik
mesh_terms: D000641:Ammonia; D019149:Bioreactors; D015386:Hazardous Substances / Q000737:chemistry*; D006861:Hydrogen Peroxide; D007501:Iron; D010084:Oxidation-Reduction; D012722:Sewage; D014865:Waste Disposal, Fluid / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000737:chemistry*
chemical_list: C045076:Fenton's reagent; D015386:Hazardous Substances; D012722:Sewage; D014874:Water Pollutants, Chemical; D000641:Ammonia; D006861:Hydrogen Peroxide; D007501:Iron