Side-stream sludge treatment using free nitrous acid selectively eliminates nitrite oxidizing bacteria and achieves the nitrite pathway

Wang, Qilin, Ye, Liu, Jiang, Guangming, Hu, Shihu and Yuan, Zhiguo (2014) Side-stream sludge treatment using free nitrous acid selectively eliminates nitrite oxidizing bacteria and achieves the nitrite pathway. Water Research, 55 245-255. doi:10.1016/j.watres.2014.02.029


Author Wang, Qilin
Ye, Liu
Jiang, Guangming
Hu, Shihu
Yuan, Zhiguo
Title Side-stream sludge treatment using free nitrous acid selectively eliminates nitrite oxidizing bacteria and achieves the nitrite pathway
Journal name Water Research   Check publisher's open access policy
ISSN 0043-1354
1879-2448
Publication date 2014-05-01
Year available 2014
Sub-type Article (original research)
DOI 10.1016/j.watres.2014.02.029
Volume 55
Start page 245
End page 255
Total pages 11
Place of publication London, United Kingdom
Publisher I W A Publishing
Collection year 2015
Language eng
Formatted abstract
Nitrogen removal via nitrite (i.e. the nitrite pathway) is beneficial for carbon-limited biological wastewater treatment plants. This study presents a novel strategy for achieving the nitrite pathway, which involves recirculating a portion of the activated sludge through a side-stream sludge treatment unit, where the sludge is subject to treatment with free nitrous acid (FNA i.e. HNO2). The strategy is proposed based on a novel discovery reported in this work that in the concentration range of 0.24-1.35mg HNO2--N/L, FNA is substantially more biocidal to nitrite oxidizing bacteria (NOB) than to ammonium oxidizing bacteria (AOB). Two sequencing batch reactors (SBR) treating synthetic domestic wastewater were used to demonstrate the concept, with one serving as an experimental reactor and the other as a control. In the experimental system, 22% of the sludge from the SBR was transferred to the side-stream treatment unit each day, and was subject to FNA treatment at 1.35mg N/L for 24h and then returned to the SBR. The nitrite pathway was rapidly (in 15d) established in the experimental reactor with an average nitrite accumulation ratio (NO2--N/(NO2--N+NO3--N)×100%) of above 80%. Fluorescence in-situ hybridization demonstrated that the NOB population in the experimental reactor was 80% lower than that in the control reactor, indicating that the majority of NOB were eliminated from the experimental reactor. The FNA-based strategy for establishing the nitrite pathway substantially improved total nitrogen removal, and did not increase N2O emission or deteriorate sludge settleability. The strategy can be easily integrated with a previously demonstrated strategy, which enhances methane production through pre-treatment of secondary activated sludge, to enable maximum energy recovery while achieving improved nitrogen removal
Keyword Free nitrous acid
Sludge treatment
Nitritation Denitritation
Nitrite pathway
Nitrous oxide (N2O)
Waste water treatment
Treatment Plants
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: School of Chemical Engineering Publications
Official 2015 Collection
Advanced Water Management Centre Publications
 
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Citation counts: TR Web of Science Citation Count  Cited 23 times in Thomson Reuters Web of Science Article | Citations
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Created: Sun, 01 Jun 2014, 10:09:57 EST by System User on behalf of Advanced Water Management Centre