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Bioconversion of Selenate in Methanogenic Anaerobic Granular Sludge
Author(s) -
Astratinei Violeta,
Hullebusch Eric,
Lens Piet
Publication year - 2006
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq2005.0443
Subject(s) - selenate , chemistry , bioconversion , selenium , environmental chemistry , methanogenesis , wastewater , anaerobic exercise , sewage sludge , biosolids , microorganism , sewage treatment , methane , environmental engineering , bacteria , food science , biology , fermentation , environmental science , organic chemistry , physiology , genetics
The capacity of anaerobic granular sludge to remove selenate from contaminated wastewater was investigated. The potential of different types of granular sludge to remove selenate from the liquid phase was compared to that of suspended sludge and contaminated soil and sediment samples. The selenate removal rates ranged from 400 to 1500 μg g VSS −1 h −1 , depending on the source of biomass, electron donor, and the initial selenate concentration. The granular structure protects the microorganisms when exposed to high selenate concentrations (0.1 to 1 m M ). Anaerobic granular sludge “Eerbeek,” originating from a UASB reactor treating paper mill wastewater, removed about 90, 50, and 36% of 0.1, 0.5, and 1 m M of Se, respectively, from the liquid phase when incubated with 20 m M lactate at 30°C and pH 7.5. Selenite, elemental Se (Se o ), and metal selenide precipitates were the conversion products. Enrichments from the anaerobic granular sludge “Eerbeek” were able to convert 90% of the 10‐m M selenate to Se o at a rate of 1505 μg Se(VI) g cells −1 h −1 , a specific growth rate of 0.0125 g cells h −1 , and a yield of 0.083 g cells mg Se −1 Both microbial metabolic processes (e.g dissimilatory reduction) as well as microbially mediated physicochemical mechanisms (adsorption and precipitation) contribute to the removal of selenate from the Se‐containing medium.