Document Detail


Bioreduction of selenate using a hydrogen-based membrane biofilm reactor.
MedLine Citation:
PMID:  16568785     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
A H2-based, denitrifying and sulfate-reducing membrane-biofilm reactor (MBfR) was shown to be effective for removing selenate (Se(VI)) from water or wastewater by reducing it to insoluble Se(0). When Se(VI) was first added to the MBfR, Se(VI) reduction--first to selenite (Se(IV)) and then mostly to Se(0)--took place immediately and then increased over three weeks, suggesting enrichment for dissimilatory selenium-reducing bacteria. Increasing the H2 pressure improved the Se(VI) reduction rate and total-Se removal, and lowering the influent Se(VI) concentration from 1000 to 260 microg Se/L increased the average Se removal to 94%, which corresponded to an effluent Se concentration of less than 12 microg Se/L, a value well below the standard of 50 microg Se/L. The fact that the effluent suspended solids contained reduced Se suggests that Se(0) was retained in the biofilm, which detached to form the effluent suspended solids. A series of short-term experiments elaborated on how decreased influent selenate loading and increased H2 pressure could systematically improve the reduction of Se(VI) and removal of total Se. Short-term experiments also demonstrated that selenate reduction improved with lower influent nitrate concentration, suggesting that H2 was more available for selenate reduction when the H2 demand for denitrification was smaller. Complete sulfate reduction, which occurred in parallel to nitrate reduction, dominated the electron-equivalent flux. Like selenate reduction, but unlike nitrate reduction, sulfate reduction was sensitive to H2 pressure and appeared to be inhibited by selenate. Finally, selenate reduction was relatively insensitive to pH in the range of 7.0 to 9.0. This research shows that the MBfR can be effective for removing Se(VI) in water or wastewater to below the 50 microg Se/L standard.
Authors:
Jinwook Chung; Robert Nerenberg; Bruce E Rittmann
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Environmental science & technology     Volume:  40     ISSN:  0013-936X     ISO Abbreviation:  Environ. Sci. Technol.     Publication Date:  2006 Mar 
Date Detail:
Created Date:  2006-03-29     Completed Date:  2006-07-27     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0213155     Medline TA:  Environ Sci Technol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1664-71     Citation Subset:  IM    
Affiliation:
Department of Civil and Environmental Engineering, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3109, USA. jinwook.chung@asu.edu
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MeSH Terms
Descriptor/Qualifier:
Biofilms*
Hydrogen / chemistry*
Hydrogen-Ion Concentration
Kinetics
Membranes, Artificial*
Oxidation-Reduction
Selenium Compounds / chemistry*
Chemical
Reg. No./Substance:
0/Membranes, Artificial; 0/Selenium Compounds; 1333-74-0/Hydrogen; 7783-08-6/selenic acid

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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