scholarly journals Denitrification kinetics indicates nitrous oxide uptake is unaffected by electron competition in Accumulibacter

2020 ◽  
Author(s):  
Roy Samarpita ◽  
Pradhan Nirakar ◽  
NG How Yong ◽  
Wuertz Stefan
Keyword(s):  
Nitrous Oxide ◽  
Electron Acceptor ◽  
Phosphorus Removal ◽  
Metabolic Model ◽  
Electron Acceptors ◽  
Treatment Technology ◽  
Denitrifying Phosphorus Removal ◽  
Terminal Electron Acceptor ◽  
Efficient Treatment ◽  
Denitrification Kinetics

ABSTRACTDenitrifying phosphorus removal is a cost and energy efficient treatment technology that relies on polyphosphate accumulating organisms (DPAOs) utilizing nitrate or nitrite as terminal electron acceptor. Denitrification is a multistep process and many organisms do not possess the complete pathway, leading to the accumulation of intermediates such as nitrous oxide (N2O), a potent greenhouse gas and ozone depleting substance. Candidatus Accumulibacter organisms are prevalent in denitrifying phosphorus removal processes and, according to genomic analyses, appear to vary in their denitrification abilities based on their lineage. Yet, denitrification kinetics and nitrous oxide accumulation by Accumulibacter after long-term exposure to either nitrate or nitrite as electron acceptor have never been compared. We investigated the preferential use of the nitrogen oxides involved in denitrification and nitrous oxide accumulation in two enrichments of Accumulibacter and a competitor – the glycogen accumulating organism Candidatus Competibacter. A metabolic model was modified to predict phosphorus removal and denitrification rates when nitrate, nitrite or N2O were added as electron acceptors in different combinations. Unlike previous studies, no N2O accumulation was observed for Accumulibacter in the presence of multiple electron acceptors. Electron competition did not affect denitrification kinetics or N2O accumulation in Accumulibacter or Competibacter. Despite the presence of sufficient internal storage polymers (polyhydroxyalkanoates, or PHA) as energy source for each denitrification step, the extent of denitrification observed was dependent on the dominant organism in the enrichment. Accumulibacter showed complete denitrification and N2O utilization, whereas for Competibacter denitrification was limited to reduction of nitrate to nitrite. These findings indicate that DPAOs can contribute to lowering N2O emissions in the presence of multiple electron acceptors under partial nitritation conditions.

Discussion of the Simultaneous Nitrogen and Phosphorus Removal Mechanism

2013 ◽  
Vol 726-731 ◽  
pp. 2156-2159 ◽  
Author(s):  
Jing Ni Xiao ◽  
Li Na Zheng ◽  
Lei Zhang ◽  
Han Min Zhang ◽  
Feng Lin Yang
Keyword(s):  
Electron Acceptor ◽  
Uptake Rate ◽  
Phosphorus Removal ◽  
Phosphorus Uptake ◽  
Electron Acceptors ◽  
Removal Mechanism ◽  
Nitrogen And Phosphorus ◽  
Denitrifying Phosphorus Removal ◽  
Nitrate Consumption ◽  
Consumption Rates

The phosphorus uptake rate characteristics have been investigated in different electron acceptor conditions (NO3-, O2, O2 and NO3- coexisting). The sludge was transferred from CAS, AO MBR, AOA MBR, A2O MBR or the A, B tank of MUCT-MBR systems. The results show that the phosphorus uptake rate (SPUR) have the same rule for the sludge in different electron acceptors, that is NSPUR (NO3- as the electron acceptor) <ASPUR (O2 as the electron acceptor) <TSPUR (both O2 and NO3- as the electron acceptors). There exists the aerobic denitrifying phosphorus removal process in mixed electron acceptor system. And this process shows a positive correlation with the ability of denitrifying phosphorus removal improved. The higher ability of denitrifying phosphorus uptake the sludge have, the faster nitrate consumption rate could be shown through the phosphorus uptake process under the condition of in O2 and NO3- coexisting. That is TSDNR（AO）<TSDNR（AOA）<TSDNR（A2O）. The relationship between the nitrate consumption rates is ASDNR (only O2 exist) <TSDNR (TP and O2 coexist) <NSDNR (only TP exist). The phosphorus removal mechanism might include three parts: the aerobic phosphorus uptake, the anoxic denitrifying phosphorus uptake and the aerobic denitrifying phosphorus uptake.

scholarly journals Nitrous oxide emission depending on the type of electron acceptor by a denitrifying phosphorus removal sludge

2016 ◽  
Vol 18 (2) ◽  
pp. 251-258 ◽  
Keyword(s):  
Nitrous Oxide ◽  
Organic Carbon ◽  
Electron Acceptor ◽  
Phosphorus Removal ◽  
Nitrogen And Phosphorus ◽  
Nitrogen And Phosphorus Removal ◽  
Denitrifying Phosphorus Removal ◽  
Organic Carbon Concentration ◽  
Polyphosphate Accumulating Organisms ◽  
Scale Reactor

<div> <p>Denitrifying polyphosphate accumulating organisms (DNPAOs) are very promising for simultaneous nitrogen and phosphorus removal. While during denitrification, emission of a greenhouse gas, nitrous oxide (N<sub>2</sub>O), may occur. In this study, DNPAOs were enriched in a lab-scale reactor, and N<sub>2</sub>O emission was examined under different electron acceptor conditions. During the anoxic phase, with the uptake of phosphorus, denitrification of nitrate nitrogen (NO<sub>3</sub>-N) was observed without the accumulation of nitrite nitrogen (NO<sub>2</sub>-N). In general, a very low amount of N<sub>2</sub>O was produced with nitrate as the electron acceptor, independent of the applied different nitrate concentrations. However, with nitrite as the electron acceptor, a much higher N<sub>2</sub>O emission occurred. The N<sub>2</sub>O emission factor to the denitrified NO<sub>2</sub>-N was 6.2%, 5.3% and 4.9% at the initial NO<sub>2</sub>-N concentration of 10, 20 and 40 mg l<sup>-1</sup>, respectively. In addition, a much higher N<sub>2</sub>O emission occurred with the co-existence of NO<sub>3</sub>-N and NO<sub>2</sub>-N. The initial organic carbon concentration had no significant effect on N<sub>2</sub>O emission with NO<sub>3</sub>-N as the electron acceptor. When stored organic carbon by DNPAOs was used as the electron donor, N<sub>2</sub>O emission was mainly dependent on the electron acceptor.&nbsp;</p> </div> <p>&nbsp;</p>

scholarly journals Population Structure and Morphotype Analysis of “CandidatusAccumulibacter” Using FluorescenceIn SituHybridization-Staining-Flow Cytometry

2019 ◽  
Vol 85 (9) ◽  
Author(s):  
Chao Li ◽  
Wei Zeng ◽  
Ning Li ◽  
Yu Guo ◽  
Yongzhen Peng
Keyword(s):  
Flow Cytometry ◽  
Population Structure ◽  
Electron Acceptor ◽  
Phosphorus Removal ◽  
Fish Analysis ◽  
Bacterial Cells ◽  
Denitrifying Phosphorus Removal ◽  
Optimal Method ◽  
Total Bacteria

ABSTRACT“CandidatusAccumulibacter” is the dominant polyphosphate-accumulating organism (PAO) in denitrifying phosphorus removal (DPR) systems. In order to investigate the community structure and clade morphotypes of “CandidatusAccumulibacter” in DPR systems through flow cytometry (FCM), denitrifying phosphorus removal of almost 100% using nitrite and nitrate as the electron acceptor was achieved in sequencing batch reactors (SBRs). An optimal method of flow cytometry combined with fluorescencein situhybridization and SYBR green I staining (FISH-staining-flow cytometry) was developed to quantify PAOs in DPR systems. By setting the width value of FCM, bacterial cells in a sludge sample were divided into three groups in different morphotypes, namely, coccus, coccobacillus, and bacillus. Average percentages that the three different PAO populations accounted for among total bacteria from SBR1 (SBR2) were 42% (45%), 14% (13%), and 4% (2%). FCM showed that the ratios of PAOs to total bacteria in the two reactors were 61% and 59%, and the quantitative PCR (qPCR) results indicated that IIC was the dominant “CandidatusAccumulibacter” clade in both denitrifying phosphorus removal systems, reaching 50% of the total “CandidatusAccumulibacter” bacteria. The subdominant clade in the reactor with nitrite as the electron acceptor was IID, accounting for 31% of the total “CandidatusAccumulibacter” bacteria. The FCM and qPCR results suggested that clades IIC and IID were both coccus, clade IIF was coccobacillus, and clade IA was bacillus. FISH analysis also indicated that PAOs were major cocci in the systems. An equivalence test of FCM-based quantification confirmed the accuracy of FISH-staining-flow cytometry, which can meet the quantitative requirements for PAOs in complex activated sludge samples.IMPORTANCEAs one group of the most important functional phosphorus removal organisms, “CandidatusAccumulibacter,” affiliated with theRhodocyclusgroup of theBetaproteobacteria, is a widely recognized and studied PAO in the field of biological wastewater treatment. The morphotypes and population structure of clade-level “CandidatusAccumulibacter” were studied through novel FISH-staining-flow cytometry, which involved denitrifying phosphorus removal (DPR) achieving carbon and energy savings and simultaneous removal of N and P, thus inferring the different denitrifying phosphorus removal abilities of these clades. Additionally, based on this method,in situquantification for specific polyphosphate-accumulating organisms (PAOs) enables a more efficient process and more accurate result. The establishment of FISH-staining-flow cytometry makes cell sorting of clade-level noncultivated organisms available.

Research of the Application of Denitrifying Phosphate Removal Bacteria in the A2/O Process

2013 ◽  
Vol 448-453 ◽  
pp. 1211-1216
Author(s):  
Meng Zhao ◽  
Shuai Bing ◽  
Xue Song Li ◽  
Meng Ru Xuan
Keyword(s):  
Phosphorus Removal ◽  
High Efficiency ◽  
Influence Factors ◽  
Research Field ◽  
Phosphate Removal ◽  
Treatment Technology ◽  
Denitrifying Phosphorus Removal ◽  
Process Stage ◽  
Removal Technology ◽  
New Type

As a new type and high efficiency and low energy consumption one in biological denitrification and phosphorus removal technology, denitrifying phosphorus removal has become a hot topic in the research field of the water treatment technology. In this technology, denitrifying phosphate removal bacteria (DPBs) plays an important role. In each process stage of an A2/O process, denitrifying phosphorus removal bacteria (DPBs) plays different function. Combining with theory of the A2/O process, the function and main influence factors of denitrifying phosphorus removal bacteria (DPBs) are studied, and the prospect about DPBs is proposed.

scholarly journals Nitrous oxide generation in denitrifying phosphorus removal process: main causes and control measures

2013 ◽  
Vol 20 (8) ◽  
pp. 5353-5360 ◽  
Author(s):  
Cong Li ◽  
Jian Zhang ◽  
Shuang Liang ◽  
Huu Hao Ngo ◽  
Wenshan Guo ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
Phosphorus Removal ◽  
Control Measures ◽  
Denitrifying Phosphorus Removal ◽  
Removal Process ◽  
And Control

Positive role of nitrite as electron acceptor on anoxic denitrifying phosphorus removal process

2007 ◽  
Vol 52 (16) ◽  
pp. 2179-2183 ◽  
Author(s):  
RongXin Huang ◽  
Dong Li ◽  
XiangKun Li ◽  
LinLin Bao ◽  
AnXi Jiang ◽  
...  
Keyword(s):  
Electron Acceptor ◽  
Phosphorus Removal ◽  
Denitrifying Phosphorus Removal ◽  
Positive Role ◽  
Removal Process

Denitrifying phosphorus removal by anaerobic/anoxic sequencing batch reactor

2001 ◽  
Vol 43 (3) ◽  
pp. 139-146 ◽  
Author(s):  
W. J. Ng ◽  
S. L. Ong ◽  
J. Y. Hu
Keyword(s):  
Removal Efficiency ◽  
Electron Acceptor ◽  
Phosphorus Removal ◽  
Sequencing Batch Reactor ◽  
Phosphate Uptake ◽  
Batch Reactor ◽  
Anoxic Condition ◽  
Simultaneous Presence ◽  
Denitrifying Phosphorus Removal ◽  
Batch Tests

Denitrifying phosphorus removal was verified in a laboratory anaerobic/anoxic Sequencing Batch Reactor (A/A SBR) for a period of 18 months. The results obtained demonstrated the ability of the anaerobic/anoxic strategy to enrich the growth of denitrifying phosphorus bacteria (DPB) capable of taking up phosphate under anoxic conditions by using nitrate as the electron acceptor. Phosphorus removal efficiency ranging from 40-100% could be attained in an A/A SBR system. Simultaneous anoxic phosphate uptake and biological denitrification under anaerobic/anoxic condition occurred in this system. Batch tests showed, however, that simultaneous presence of carbon and nitrate would be detrimental to denitrifying phosphorus removal. Results of bacteria studies suggested that three denitrifying isolates had aerobic phosphorus removing ability.

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