title: Anaerobic degradation of landfill leachate using an upflow anaerobic fixed-bed reactor with microbial sulfate reduction.
abstract: This study evaluated the anaerobic degradation of landfill leachate and sulfate reduction as a function of COD/(SO(4)(2-)) ratio in an upflow anaerobic fixed-bed reactor. The reactor, which was inoculated with a mixed consortium, was operated under a constant hydraulic retention time (HRT) of 5 days. We investigated the effect of COD/(SO(4)(2-)) ratio variation on the sulfate reduction efficiency, hydrogen sulfide production, chemical oxygen demand (COD) removal, conductivity, and pH variation. The best reactor performance, with significant sulfate reduction efficiency and COD removal efficiency of 91% and 87%, respectively, was reached under a COD/(SO(4)(2-)) ratio of 1.17. Under these conditions, microscopic analysis showed the abundance of vibrios and rod-shaped bacterial cells. Two anaerobic bacteria were isolated from the reactor sludge. Phylogenetic studies performed on these strains identified strain A1 as affiliated to Clostridium genus and strain H1 as a new species of sulfate-reducing bacteria affiliated to the Desulfovibrio genus. The closest phylogenetic relative of strain H1 was Desulfovibrio desulfuricans, at 96% similarity for partial 16S RNA gene sequence data. Physiological and metabolic characterization was performed for this strain.
authors.affiliation: Laboratory of Ecology and Microbial Technology, National Institute of Applied Sciences and Technology, 2 Boulevard de la Terre, Tunis, Tunisia.
authors.forename: Olfa Ben Dhia
authors.initials: OB
authors.lastname: Thabet
authors.forename: Hassib
authors.initials: H
authors.lastname: Bouallagui
authors.forename: Jean-luc
authors.initials: JL
authors.lastname: Cayol
authors.forename: Bernard
authors.initials: B
authors.lastname: Ollivier
authors.forename: Marie-Laure
authors.initials: ML
authors.lastname: Fardeau
authors.forename: Moktar
authors.initials: M
authors.lastname: Hamdi
mesh_terms: D000693:Anaerobiosis; D001421:Bacteria, Anaerobic / Q000378:metabolism*; D001673:Biodegradation, Environmental; D019149:Bioreactors; D003013:Clostridium / Q000302:isolation & purification / Q000378:metabolism; D003901:Desulfovibrio / Q000302:isolation & purification / Q000378:metabolism; D006862:Hydrogen Sulfide; D013431:Sulfates / Q000378:metabolism*; D014874:Water Pollutants, Chemical / Q000378:metabolism*
chemical_list: D013431:Sulfates; D014874:Water Pollutants, Chemical; D006862:Hydrogen Sulfide