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Title: On the occurrence of anoxic microniches, denitrification, and sulfate reduction in aerated activated sludge

Abstract

A combination of different methods was applied to investigate the occurrence of anaerobic processes in aerated activated sludge. Microsensor measurements (O{sub 2}, NO{sub 2}{sup {minus}}, NO{sub 3}{sup {minus}}, and H{sub 2}S) were performed on single sludge flocs to detect anoxic niches, nitrate reduction, or sulfate reduction on a microscale. Incubations of activated sludge with {sup 15}NO{sub 3}{sup {minus}} and {sup 35}SO{sub 4}{sup 2{minus}} were used to determine denitrification and sulfate reduction rates on a batch scale. In four of six investigated sludges, no anoxic zones developed during aeration, and consequently denitrification rates were very low. However, in two sludges anoxia in flocs coincided with significant denitrification rates. Sulfate reduction could not be detected in any sludge in either the microsensor or the batch investigation, not even under short-term anoxic conditions. In contrast, the presence of sulfate-reducing bacteria was shown by fluorescence in situ hybridization with 16S rRNA-targeted oligonucleotide probes and by PCR-based detection of genes coding for the dissimilatory sulfite reductase. A possible explanation for the absence of advection, i.e., facilitated by flow through pores and channels. This possibility is suggested by the irregularity of some oxygen profiles and by confocal laser scanning microscopy of the three-dimensional floc structures, whichmore » showed that flocs from the two sludges in which anoxic zones were found were apparently denser than flocs from the other sludges.« less

Authors:
; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Max Planck Inst. for Marine Microbiology, Bremen (DE)
OSTI Identifier:
20000244
Alternate Identifier(s):
OSTI ID: 20000244
Resource Type:
Journal Article
Journal Name:
Applied and Environmental Microbiology
Additional Journal Information:
Journal Volume: 65; Journal Issue: 9; Other Information: PBD: Sep 1999; Journal ID: ISSN 0099-2240
Country of Publication:
United States
Language:
English
Subject:
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION; SULFATES; ACTIVATED SLUDGE PROCESS; ANOXIA; DENITRIFICATION; NITRATES; SULFATE-REDUCING BACTERIA

Citation Formats

Schramm, A., Santegoeds, C.M., Nielsen, H.K., Ploug, H., Wagner, M., Pribyl, M., Wanner, J., Amann, R., and De Beer, D. On the occurrence of anoxic microniches, denitrification, and sulfate reduction in aerated activated sludge. United States: N. p., 1999. Web.
Schramm, A., Santegoeds, C.M., Nielsen, H.K., Ploug, H., Wagner, M., Pribyl, M., Wanner, J., Amann, R., & De Beer, D. On the occurrence of anoxic microniches, denitrification, and sulfate reduction in aerated activated sludge. United States.
Schramm, A., Santegoeds, C.M., Nielsen, H.K., Ploug, H., Wagner, M., Pribyl, M., Wanner, J., Amann, R., and De Beer, D. Wed . "On the occurrence of anoxic microniches, denitrification, and sulfate reduction in aerated activated sludge". United States.
@article{osti_20000244,
title = {On the occurrence of anoxic microniches, denitrification, and sulfate reduction in aerated activated sludge},
author = {Schramm, A. and Santegoeds, C.M. and Nielsen, H.K. and Ploug, H. and Wagner, M. and Pribyl, M. and Wanner, J. and Amann, R. and De Beer, D.},
abstractNote = {A combination of different methods was applied to investigate the occurrence of anaerobic processes in aerated activated sludge. Microsensor measurements (O{sub 2}, NO{sub 2}{sup {minus}}, NO{sub 3}{sup {minus}}, and H{sub 2}S) were performed on single sludge flocs to detect anoxic niches, nitrate reduction, or sulfate reduction on a microscale. Incubations of activated sludge with {sup 15}NO{sub 3}{sup {minus}} and {sup 35}SO{sub 4}{sup 2{minus}} were used to determine denitrification and sulfate reduction rates on a batch scale. In four of six investigated sludges, no anoxic zones developed during aeration, and consequently denitrification rates were very low. However, in two sludges anoxia in flocs coincided with significant denitrification rates. Sulfate reduction could not be detected in any sludge in either the microsensor or the batch investigation, not even under short-term anoxic conditions. In contrast, the presence of sulfate-reducing bacteria was shown by fluorescence in situ hybridization with 16S rRNA-targeted oligonucleotide probes and by PCR-based detection of genes coding for the dissimilatory sulfite reductase. A possible explanation for the absence of advection, i.e., facilitated by flow through pores and channels. This possibility is suggested by the irregularity of some oxygen profiles and by confocal laser scanning microscopy of the three-dimensional floc structures, which showed that flocs from the two sludges in which anoxic zones were found were apparently denser than flocs from the other sludges.},
doi = {},
journal = {Applied and Environmental Microbiology},
issn = {0099-2240},
number = 9,
volume = 65,
place = {United States},
year = {1999},
month = {9}
}