| Stratification and oxidation-reduction potential change in an aerobic and sulfate-reducing biofilm studied using microelectrodes. | |
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MedLine Citation:
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PMID: 11561597 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Recent studies in aerobic-nitrifying biofilms demonstrated the heterogeneity of biofilms used in wastewater treatment and led to modifications of the homogeneous assumptions in the conventional biofilm kinetic models. However, the stratification in aerobic-anaerobic biofilms has not been well investigated because of a lack of effective experimental tools. In this study a suite of microelectrodes, recently developed in the authors' laboratory, was used to examine the stratification of microbial processes and the change of oxidation-reduction potential (ORP) within an aerobic, sulfate-reducing biofilm. The microelectrodes have tip diameters of 3 to 20 microm and a high spatial resolution. They were used to measure the profiles of oxygen, total dissolved sulfide, ORP, and pH as a function of depth in the biofilm. The biofilm reactor was used to treat an azo-dye-containing wastewater with a chemical oxygen demand of 160 mg/L. The reactor bulk-phase dissolved oxygen concentration of the biofilm was 1.7 mg/L. The experimental results demonstrated that the microbial processes in the biofilm were stratified. In this biofilm, aerobic oxidation took place only in a shallow layer of 0.55 mm near the surface and sulfate reduction occurred in the deeper anoxic zone. The ORP changed with the shift of primary microbial process. The ORP was +362 mV at the biofilm surface and -166 mV near the substratum. Near the interface between the aerobic zone and the sulfate reduction zone, a surprisingly sharp decrease of ORP from a positive potential of +194 mV to a negative potential of -77 mV was observed. This occurred within a narrow band of 50 microm in depth. These new experimental findings support the concept of stratification of microbial processes and the associated ORP change in biofilms. |
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Authors:
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T Yu; P L Bishop |
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Publication Detail:
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Type: Journal Article; Research Support, U.S. Gov't, P.H.S. |
Journal Detail:
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Title: Water environment research : a research publication of the Water Environment Federation Volume: 73 ISSN: 1061-4303 ISO Abbreviation: Water Environ. Res. Publication Date: 2001 May-Jun |
Date Detail:
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Created Date: 2001-09-19 Completed Date: 2001-10-25 Revised Date: 2006-11-15 |
Medline Journal Info:
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Nlm Unique ID: 9886167 Medline TA: Water Environ Res Country: United States |
Other Details:
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Languages: eng Pagination: 368-73 Citation Subset: IM |
Affiliation:
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University of Cincinnati, USA. Tong.Yu@ualberta.ca |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Azo Compounds
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metabolism Bacteria, Anaerobic / physiology* Biofilms* Hydrogen-Ion Concentration Microelectrodes Oxidation-Reduction Population Dynamics Sulfates / analysis, chemistry* Sulfides / analysis, chemistry Waste Disposal, Fluid* |
| Chemical | |
Reg. No./Substance:
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0/Azo Compounds; 0/Sulfates; 0/Sulfides |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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