Long-term impact of anaerobic reaction time on the performance and granular characteristics of granular denitrifying biological phosphorus removal systems

Wang, Yayi, Guo, Gang, Wang, Hong, Stephenson, Tom, Guo, Jianhua and Ye, Liu (2013) Long-term impact of anaerobic reaction time on the performance and granular characteristics of granular denitrifying biological phosphorus removal systems. Water Research, 47 14: 5326-5237. doi:10.1016/j.watres.2013.06.013


Author Wang, Yayi
Guo, Gang
Wang, Hong
Stephenson, Tom
Guo, Jianhua
Ye, Liu
Title Long-term impact of anaerobic reaction time on the performance and granular characteristics of granular denitrifying biological phosphorus removal systems
Journal name Water Research   Check publisher's open access policy
ISSN 0043-1354
1879-2448
Publication date 2013-09-15
Sub-type Article (original research)
DOI 10.1016/j.watres.2013.06.013
Volume 47
Issue 14
Start page 5326
End page 5237
Total pages 12
Place of publication London, United Kingdom
Publisher I W A Publishing
Language eng
Formatted abstract
Highlights
• Long-term effect of AnRT was tested in granular denitrifying P removal systems.
• FNA accumulated frequently in the longest AnRT case due to the shortage of PHA.
• FNA and frequent endogenous exposure stimulated more EPS production by microorganism.
• The largest granule developed in the longest AnRT SBR with the highest GAOs.
• EPS adsorption contributed partially to the P removal in the higher GAOs granular system.

Removal of nitrogen and phosphorus (P) from wastewater is successfully and widely practiced in systems employing both granular sludge technology and enhanced biological P removal (EBPR) processes; however, the key parameter, anaerobic reaction time (AnRT), has not been thoroughly investigated. Successful EBPR is highly dependent on an appropriate AnRT, which induces carbon and polyphosphate metabolism by phosphorus accumulating organisms (PAOs). Therefore, the long-term impact of AnRT on denitrifying P removal performance and granular characteristics was investigated in three identical granular sludge sequencing batch reactors with AnRTs of 90 (R1), 120 (R2) and 150 min (R3). The microbial community structures and anaerobic stoichiometric parameters related to various AnRTs were monitored over time. Free nitrite acid (FNA) accumulation (e.g., 0.0008–0.0016 mg HNO2–N/L) occurred frequently owing to incomplete denitrification in the adaptation period, especially in R3, which influenced the anaerobic/anoxic intracellular intermediate metabolites and activities of intracellular enzymes negatively, resulting in lower levels of poly-P and reduced activity of polyphosphate kinase. As a result, the Accumulibacter-PAOs population decreased from 51 ± 2.5% to 43 ± 2.1% when AnRT was extended from 90 to 150 min, leading to decreased denitrifying P removal performance. Additionally, frequent exposure of microorganisms to the FNA accumulation and anaerobic endogenous conditions in excess AnRT cases (e.g., 150 min) stimulated increased extracellular polymeric substances (EPS) production by microorganisms, resulting in enhanced granular formation and larger granules (size of 0.6–1.2 mm), but decreasing anaerobic PHA synthesis and glycogen hydrolysis. Phosphorus removal capacity was mediated to some extent by EPS adsorption in granular sludge systems that possessed more EPS, longer AnRT and relatively higher GAOs.
Keyword Denitrifying phosphorus removal
Anaerobic reaction time
Denitrifying phosphate-accumulating organisms
Granules
Extracellular polymeric substances
Phosphorus fractions
Microbial community
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 2014 Collection
Advanced Water Management Centre Publications
 
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Citation counts: TR Web of Science Citation Count  Cited 27 times in Thomson Reuters Web of Science Article | Citations
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Created: Thu, 19 Sep 2013, 07:18:28 EST by Jianhua Guo on behalf of Advanced Water Management Centre