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Effect of COD/N ratio on N2O production during nitrogen removal by aerobic granular sludge.
- Source :
- Water Science & Technology; 2017, Vol. 76 Issue 12, p3452-3460, 9p, 2 Charts, 3 Graphs
- Publication Year :
- 2017
-
Abstract
- N<subscript>2</subscript>O-production was investigated during nitrogen removal using aerobic granular sludge (AGS) technology. A pilot sequencing batch reactor (SBR) with AGS achieved an effluent in accordance with national discharge limits, although presented a nitrite accumulation rate of 95.79% with no simultaneous nitrification–denitrification. N<subscript>2</subscript>O production was 2.06 mg L<superscript>−1</superscript> during the anoxic phase, with N<subscript>2</subscript>O emission during air pulses and the aeration phase of 1.6% of the nitrogen loading rate. Batch tests with AGS from the pilot reactor verified that at the greatest COD/N ratio (1.55), the N<subscript>2</subscript>O production (1.08 mgN<subscript>2</subscript>O-N L<superscript>−1</superscript>) and consumption (up to 0.05 mgN<subscript>2</subscript>O-N L<superscript>−1</superscript>), resulted in the lowest remaining dissolved N<subscript>2</subscript>O (0.03 mgN<subscript>2</subscript>O-N L<superscript>−1</superscript>), stripping the minimum N<subscript>2</subscript>O gas (0.018 mgN<subscript>2</subscript>O-N L<superscript>−1</superscript>). Conversely, the carbon supply shortage, under low C/N ratios, increased N<subscript>2</subscript>O emission (0.040 mgN<subscript>2</subscript>O-N L<superscript>−1</superscript>), due to incomplete denitrification. High abundance of ammonia-oxidizing and low abundance of nitrite-oxidizing bacteria were found, corroborating the fact of partial nitrification. A denitrifying heterotrophic community, represented mainly by Pseudoxanthomonas, was predominant in the AGS. Overall, the AGS showed stable partial nitrification ability representing capital and operating cost savings. The SBR operation flexibility could be advantageous for controlling N<subscript>2</subscript>O emissions, and extending the anoxic phase would benefit complete denitrification in cases of low C/N influents. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 02731223
- Volume :
- 76
- Issue :
- 12
- Database :
- Complementary Index
- Journal :
- Water Science & Technology
- Publication Type :
- Academic Journal
- Accession number :
- 126755079
- Full Text :
- https://doi.org/10.2166/wst.2017.502