Please wait a minute...
Shopping Cart Email List Chinese
Advanced Search Fig/Tab
Frontiers of Environmental Science & Engineering

ISSN 2095-2201

ISSN 2095-221X(Online)

CN 10-1013/X

Postal Subscription Code 80-973

2018 Impact Factor: 3.883

Featured Articles  |  Most Downloaded  |  Most Reading
Online Submission Subscribe to Our RSS Content Feed
Front. Environ. Sci. Eng.    2022, Vol. 16 Issue (8) : 101    https://doi.org/10.1007/s11783-022-1522-y
RESEARCH ARTICLE
Enhancing the efficiency of nitrogen removing bacterial population to a wide range of C:N ratio (1.5:1 to 14:1) for simultaneous C & N removal
Shaswati Saha1, Rohan Gupta2, Shradhanjali Sethi1,2, Rima Biswas1,2()
1. Academy of Scientific and Innovative Research (AcSIR), CSIR-Human Resource Development Centre (CSIR-HRDC), Ghaziabad Uttar Pradesh-201002, India
2. Wastewater Technology Division, CSIR-National Environmental Engineering Research Institute, Nagpur Maharashtra-440020, India
 Download: PDF(2288 KB)   HTML
 Export: BibTeX | EndNote | Reference Manager | ProCite | RefWorks
Abstract

• Simultaneous C & N removal in Methammox occurs at wide C:N ratio.

• Biological Nitrogen Removal at wide C:N ratio of 1.5:1 to 14:1 is not reported.

• Ammonia removal shifted from mixotrophy to heterotrophy at high C:N ratio.

• Acetogenic population compensated for ammonia oxidizers at high C:N ratio.

• Methanogens increase the plasticity of nitrogen removers at high C:N ratio.

High C:N ratio in the wastewater limits biological nitrogen removal (BNR), especially in anammox based technologies. The present study attempts to improve the COD tolerance of the BNR process by associating methanogens with nitrogen removing bacterial (NRB) populations. The new microbial system coined as ‘Methammox’, was investigated for simultaneous removal of COD (C) and ammonia (N) at C:N ratio 1.5:1 to 14:1. The ammonia removal rate (11.5 mg N/g VSS/d) and the COD removal rates (70.6 mg O/g VSS/d) of Methammox was close to that of the NRB (11.1 mg N/g VSS/d) and the methanogenic populations (77.9 mg O/g VSS/d), respectively. The activities established that these two populations existed simultaneously and independently in ‘Methammox’. Further studies in biofilm reactor fetched a balanced COD and ammonia removal (55%–60%) at a low C:N ratio (≤2:1) and high C:N ratio (≥9:1). The population abundance of methanogens was reasonably constant, but the nitrogen removal shifted from mixotrophy to heterotrophy as the C:N ratio shifted from low (C:N≤2:1) to high (C:N≥9:1). The reduced autotrophic NRB (ammonia- and nitrite-oxidizing bacteria and Anammox) population at a high C:N ratio was compensated by the fermentative group that could carry out denitrification heterotrophically. The functional plasticity of the Methammox system to adjust to a broad C:N ratio opens new frontiers in biological nitrogen removal of high COD containing wastewaters.
Keywords Methanogens      Biological Nitrogen Removal (BNR)      Simultaneous      Methammox      C:N ratio     
Corresponding Author(s): Rima Biswas   
About author:

Tongcan Cui and Yizhe Hou contributed equally to this work.
Issue Date: 21 December 2021
 Cite this article:   
Shaswati Saha,Rohan Gupta,Shradhanjali Sethi, et al. Enhancing the efficiency of nitrogen removing bacterial population to a wide range of C:N ratio (1.5:1 to 14:1) for simultaneous C & N removal[J]. Front. Environ. Sci. Eng., 2022, 16(8): 101.
 URL:  
https://academic.hep.com.cn/fese/EN/10.1007/s11783-022-1522-y
https://academic.hep.com.cn/fese/EN/Y2022/V16/I8/101
Sr No. Days Phases Mean inlet ammonia (mg NH4+-N/L) Mean inlet COD (mg/L) C:N ratio
1 0–19 I 100.2±17.7 154.45±23.8 1.5
2 20–40 II 97.0±26.8 227.7±27.7 2.3
3 41–79 III 82.6±13.2 488.8±36.2 6
4 80–100 IV 96.4±21.4 783.6±54.7 8
5 101–145 V 90.5±11.3 804.5±56.8 9
6 146–187 VI 98.8±16.7 1380.2±76.2 14
Tab.1  Operation of Biofilm Reactor at various C:N ratios
Fig.1  Line graphs showing the average concentrations of COD (mg/L), ammonia (mg N/L), nitrite (mg N/L), and nitrate (mg N/L) and headspace pressure (mBar) in N, C and N+ C substrates inoculated with (a and b) methanogenic biomass (MB), (c and d) Nitrogen removing bacteria (NRB) and (e and f) methammox.
Fig.2  Bar graphs showing activities of methanogenic biomass (MB), nitrogen removing bacterial (NRB) groups and Methammox in terms of ammonia and COD removal rates (ARR and CRR). Each of the biomasses was inoculated with ammonia (N), ammonia and methanol (N+ C) and methanol (C) as substrates. The blue bar represents ARR and the green bars represents CRR. The vertical lines in the graph represent Y-axis error. The rates that do not have statistically (p≤0.005) different values between two different experimental set-ups when determined by a two-way analysis of variance (ANOVA) test are denoted the same alphabets, while those with statistically significant differences are denoted different alphabets above the bar.
Fig.3  Effect of various C:N ratios on batch experimental data of Methammox. The black line plot represents ammonia removal rate (ARR) and the red line plot represents per cent methane concentration in the headspace. The vertical lines in the graph represent the Y-axis error.
Fig.4  (a) Effect of various C:N ratios on the performance of Methammox biofilm reactor. The blue, red and the black line plots represent percent COD removal efficiency (% CODRE), ammonia removal efficiency (% ARE), and total nitrogen removal efficiency (% TNRE) respectively. The vertical lines in the graph represent the Y-axis error. (b) Principal component analysis (PCA) performed on biofilm reactor data operated at various C:N ratios (2:1, 6:1, 8:1, 9:1 and 14:1). The first principal component is C:N ratio and the second component is inlet ammonia concentration (mg N/L) and ammonia removal efficiency (ARE %). The gray, orange, blue and purple-colored ovals represent biplot scores of the reactor operated C:N ratio at 14:1, 9:1, 6:1 and 2:1, respectively.
Fig.5  The alpha and beta diversity of the taxonomic profiles of biofilm reactor at C:N ratios 1.5:1 (mgm 4865364.3), 2:1 (mgm 4865391.3), 9:1 (mgm 4848784.3) and 14:1 (mgm 4848783.3) was statistically analyzed using (a) the Venn diagram and (b) Principal Component Analysis (PCA) plot, respectively.
Fig.6  Stacked bar plots showing per cent relative abundances of populations at C:N ratios 1.5:1, 2:1, 9:1 and 14:1 at (a) phyla, (b) order and (c) class levels.
Functional Group Phylum Genera Abundance (%) at C:N ratio
1.5:1 2:1 9:1 14:1
Methanogens Archaea Methanobacterium 0.01 0.01 2.71 3.80
Methanosaeta 0.07 0.08 4.11 4.18
Methanomethylovorans 7.51 7.57 <0.01 <0.01
Methanolobus 0.02 0.25 <0.01 <0.01
Anammox Planctomycetes Candidatus kuenenia 1.60 1.70 0.30 0.20
Non-Anammox Isosphaera 0.01 0.31 0.00 0.19
Planctomyces 0.21 1.08 0.01 0.09
Blastopirellula 0.04 0.01 0.02 0.03
Pirellula 0.52 0.03 0.04 0.01
Nitrifiers Proteobacteria Nitrosomonas 1.30 1.30 0.06 0.03
Nitrobacter <0.01 0.01 <0.01 <0.01
Nitrospira <0.01 <0.01 <0.01 <0.01
Methane Oxidizers Proteobacteria Methylobacillus 0.01 0.21 <0.01 0.01
Methylocaldum 0.04 1.87 <0.01 <0.01
Methylobacillus 0.01 0.21 <0.01 0.01
Denitrifiers Proteobacteria Rhodocyclaceae 0.32 0.23 <0.01 <0.01
Alcaligens* <0.01 <0.01 0.17 0.08
Sphingomonas 0.02 0.05 0.01 0.05
Comamonas* 0.05 0.08 0.03 0.03
Comamonadacecae (Unclassified) 0.01 0.06 0.02 0.29
Dechloromonas <0.01 0.05 <0.01 <0.01
Bdellovibrio 0.05 <0.01 <0.01 0.05
Pseudomonas* 0.03 0.01 <0.01 0.03
Paracoccus* 0.08 0.01 0.02 <0.01
Rhodopseudomonas 0.07 0.41 0.12 0.01
Thauera* 0.01 0.01 <0.01 <0.01
Thiothrix* 0.29 0.01 <0.01 <0.01
Hydrogenophaga 0.21 <0.01 <0.01 <0.01
Achromobacter* <0.01 <0.01 <0.01 <0.01
Agrobacterium* <0.01 <0.01 <0.01 <0.01
Marinomonas* 0.04 <0.01 <0.01 <0.01
Actinobacteria Micrococcus <0.01 <0.01 <0.01 <0.01
Bacteroidetes Terrimonas 0.58 0.87 0.02 0.02
Flavobacterium 1.45 0.59 0.13 <0.01
Firmicutes Clostridium 1.78 1.83 16.63 11.59
Clostridiales (Unclassified) 0.08 0.09 1.14 4.49
Geobacillus* 0.11 <0.01 1.82 0.10
Alicyclobacillus 0.30 0.03 1.76 0.06
Bacillus* 0.21 0.36 1.25 0.88
Sedimentibacter* <0.01 0.07 2.97 1.10
Tab.2  Abundance of various microbial groups in Methammox at various C:N ratios
Fig.7  Extended error bar plots showing significant differences (p<0.05) between mean populations (genera) in low (1.5:1 and 2:1) and high (9:1 and 14:1) C:N ratios shown in orange and blue bars, respectively. Corrected p values are shown at the right.
Fig.8  (a) Scanning electron micrograph of Methammox biofilm taken from the Biofilm Reactor. The discreet clusters of large coccoid bacterial cells having ~1 µm diameter and those with smaller diameter (0.1–0.2 µm) are shown with colored arrows. (b) Schematic representation of Methammox Biofilm consisting of independent clusters of Nitrogen Reducing Bacterial (NRB) group and methanogenic bacterial (MB) group. The two clusters are interspaced with methane-oxidizing bacteria and denitrifiers which take substrates from both groups. The interspacing by the MOB and denitrifiers separate the NRB and MB making them functionally independent of each other. The denitrifiers that participate in nitrogen metabolism at a high C:N ratio also provide fermentative end products for methanogens.
1 APHA (2017). Standard methods for the examination of water and waste water, 23rd ed. Washington, DC: American Public Health Association
2 S Bagchi, R Biswas, T Nandy (2010). Alkalinity and dissolved oxygen as controlling parameters for ammonia removal through partial nitritation and ANAMMOX in a single-stage bioreactor. Journal of Industrial Microbiology & Biotechnology, 37(8): 871–876
https://doi.org/10.1007/s10295-010-0744-3 pmid: 20544258
3 S Bagchi, R Biswas, T Nandy (2012). Autotrophic ammonia removal processes: Ecology to technology. Critical Reviews in Environmental Science and Technology, 42(13): 1353–1418
https://doi.org/10.1080/10643389.2011.556885
4 Z Bi, M Takekawa, G Park, S Soda, J Zhou, S Qiao, M Ike (2015). Effects of the C/N ratio and bacterial populations on nitrogen removal in the simultaneous anammox and heterotrophic denitrification process: Mathematic modelling and batch experiments. Chemical Engineering Journal, 280: 606–613
https://doi.org/10.1016/j.cej.2015.06.028
5 S Cao, R Du, Y Peng, B Li, S Wang (2020). Novel two-stage partial denitrification (PD)-Anammox process for tertiary nitrogen removal from low carbon/nitrogen (C/N) municipal sewage. Chemical Engineering Journal, 362: 107–115
6 N Chamchoi, S Nitisoravut, J E Schmidt (2008). Inactivation of ANAMMOX communities under concurrent operation of anaerobic ammonium oxidation (ANAMMOX) and denitrification. Bioresource Technology, 99(9): 3331–3336
https://doi.org/10.1016/j.biortech.2007.08.029 pmid: 17911013
7 C Chen, F Sun, H Zhang, J Wang, Y Shen, X Liang (2016). Evaluation of COD effect on anammox process and microbial communities in the anaerobic baffled reactor (ABR). Bioresource Technology, 216: 571–578
https://doi.org/10.1016/j.biortech.2016.05.115 pmid: 27285572
8 R G B de Almeida, dos C E D Santos, T C Lüders, V Del Nery, C D Leal, A D Pereira, J C Araújo, R J Davenport, A C Barana, D D Lopes, M H R Z Damianovic (2018). Nitrogen removal by simultaneous partial nitrification, anammox and denitrification (SNAD) in a structured-bed reactor treating animal feed processing wastewater: Inhibitory effects and bacterial community. International Biodeterioration & Biodegradation, 133: 108–115
https://doi.org/10.1016/j.ibiod.2018.06.019
9 E E Díaz, A J Stams, R Amils, J L Sanz (2006). Phenotypic properties and microbial diversity of methanogenic granules from a full-scale upflow anaerobic sludge bed reactor treating brewery wastewater. Applied and Environmental Microbiology, 72(7): 4942–4949
https://doi.org/10.1128/AEM.02985-05 pmid: 16820491
10 I A Fotidis, D Karakashev, I Angelidaki (2013). Bioaugmentation with an acetate-oxidising consortium as a tool to tackle ammonia inhibition of anaerobic digestion. Bioresource Technology, 146: 57–62
https://doi.org/10.1016/j.biortech.2013.07.041 pmid: 23916979
11 Y Gu, Y Wei, Q Xiang, K Zhao, X Yu, X Zhang, C Li, Q Chen, H Xiao, X Zhang (2019). C:N ratio shaped both taxonomic and functional structure of microbial communities in livestock and poultry breeding wastewater treatment reactor. Science of the Total Environment, 651(Pt 1): 625–633
https://doi.org/10.1016/j.scitotenv.2018.09.234 pmid: 30245418
12 A J Holmes, A Costello, M E Lidstrom, J C Murrell (1995). Evidence that particulate methane monooxygenase and ammonia monooxygenase may be evolutionarily related. FEMS Microbiology Letters, 132(3): 203–208
https://doi.org/10.1111/j.1574-6968.1995.tb07834.x pmid: 7590173
13 A Joss, D Salzgeber, J Eugster, R König, K Rottermann, S Burger, P Fabijan, S Leumann, J Mohn, H Siegrist (2009). Full-scale nitrogen removal from digester liquid with partial nitritation and anammox in one SBR. Environmental Science & Technology, 43(14): 5301–5306
https://doi.org/10.1021/es900107w pmid: 19708357
14 M Kumar, J G Lin (2010). Co-existence of anammox and denitrification for simultaneous nitrogen and carbon removal: Strategies and issues. Journal of Hazardous Materials, 178(1–3): 1–9
https://doi.org/10.1016/j.jhazmat.2010.01.077 pmid: 20138428
15 P Lam, M M Kuypers (2011). Microbial nitrogen cycling processes in oxygen minimum zones. Annual Review of Marine Science, 3(1): 317–345
https://doi.org/10.1146/annurev-marine-120709-142814 pmid: 21329208
16 S Navada, M F Knutsen, I Bakke, O Vadstein (2020). Nitrifying biofilms deprived of organic carbon show higher functional resilience to increases in carbon supply. Scientific Reports, 10(1): 7121
https://doi.org/10.1038/s41598-020-64027-y pmid: 32346018
17 S Q Ni, J Y Ni, D L Hu, S Sung (2012). Effect of organic matter on the performance of granular anammox process. Bioresource Technology, 110: 701–705
https://doi.org/10.1016/j.biortech.2012.01.066 pmid: 22342041
18 G Pekyavas, C Yangin-Gomec (2019). Response of Anammox bacteria to elevated nitrogen and organic matter in pre-digested chicken waste at a long-term operated UASB reactor initially seeded by methanogenic granules. Bioresource Technology Reports, 7: 100222
https://doi.org/doi.org/10.1016/j.biteb.2019.100222
19 L Pelaz, A Gómez, A Letona, G Garralón, M Fdz-Polanco (2018). Nitrogen removal in domestic wastewater. Effect of nitrate recycling and COD/N ratio. Chemosphere, 212: 8–14
https://doi.org/10.1016/j.chemosphere.2018.08.052 pmid: 30138857
20 L Peng, W B Nie, J Ding, B J Ni, Y Liu, H J Han, G J Xie (2020). Denitrifying anaerobic methane oxidation and anammox process in a membrane aerated membrane bioreactor: kinetic evaluation and optimization. Environmental Science & Technology, 54(11): 6968–6977
https://doi.org/10.1021/acs.est.0c01154 pmid: 32348129
21 A D Pereira, A Cabezas, C Etchebehere, C A D L Chernicharo, J C de Araújo (2017). Microbial communities in anammox reactors: A review. Environmental Technology Reviews, 6(1): 74–93
https://doi.org/10.1080/21622515.2017.1304457
22 L M Pitombo, J B do Carmo, M de Hollander, R Rossetto, M V López, H Cantarella, E E Kuramae (2016). Exploring soil microbial 16S rRNA sequence data to increase carbon yield and nitrogen efficiency of a bioenergy crop. GCB Bioenergy, 8(5): 867–879
https://doi.org/10.1111/gcbb.12284
23 L Rachbauer, R Beyer, G Bochmann, W Fuchs (2017). Characteristics of adapted hydrogenotrophic community during biomethanation. Science of the Total Environment, 595: 912–919
https://doi.org/10.1016/j.scitotenv.2017.03.074 pmid: 28432991
24 D Roy, K Hassan, R Boopathy (2010). Effect of carbon to nitrogen (C:N) ratio on nitrogen removal from shrimp production wastewater using sequencing batch reactor. Journal of Industrial Microbiology & Biotechnology, 37(10): 1105–1110
https://doi.org/10.1007/s10295-010-0869-4
25 S Saha, N Badhe, J De Vrieze, R Biswas, T Nandy (2015). Methanol induces low temperature resilient methanogens and improves methane generation from domestic wastewater at low to moderate temperatures. Bioresource Technology, 189: 370–378
https://doi.org/10.1016/j.biortech.2015.04.056 pmid: 25913884
26 S Saha, J De Vrieze, R Biswas, T Nandy (2018). In situ ammonia removal by methanogenic granular biomass. Environmental Science: Water Research & Technology, 4(4): 559–568
https://doi.org/10.1039/C7EW00444C
27 D Shu, Y He, H Yue, J Gao, Q Wang, S Yang (2016). Enhanced long-term nitrogen removal by organotrophic anammox bacteria under different C/N ratio constraints: quantitative molecular mechanism and microbial community dynamics. RSC Advances, 6(90): 87593–87606
https://doi.org/10.1039/C6RA04114K
28 B Sinha, A P Annachhatre (2007). Assessment of partial nitrification reactor performance through microbial population shift using quinone profile, FISH and SEM. Bioresource Technology, 98(18): 3602–3610
https://doi.org/10.1016/j.biortech.2006.11.034 pmid: 17257833
29 L Steuernagel, E L de Léon Gallegos, A Azizan, A K Dampmann, M Azari, M Denecke (2018). Availability of carbon sources on the ratio of nitrifying microbial biomass in an industrial activated sludge. International Biodeterioration & Biodegradation, 129: 133–140
https://doi.org/10.1016/j.ibiod.2018.02.001
30 C Sundberg, W A Al-Soud, M Larsson, E Alm, S S Yekta, B H Svensson, S J Sørensen, A Karlsson (2013). 454 pyrosequencing analyses of bacterial and archaeal richness in 21 full-scale biogas digesters. FEMS Microbiology Ecology, 85(3): 612–626
https://doi.org/10.1111/1574-6941.12148 pmid: 23678985
31 C J Tang, P Zheng, L Zhang, J W Chen, Q Mahmood, X G Chen, B L Hu, C H Wang, Y Yu (2010). Enrichment features of anammox consortia from methanogenic granules loaded with high organic and methanol contents. Chemosphere, 79(6): 613–619
https://doi.org/10.1016/j.chemosphere.2010.02.045 pmid: 20334892
32 A A van de Graaf, P De Bruijn, L A Robertson, M S Jetten, J G Kuenen (1996). Autotrophic growth of anaerobic ammonium-oxidizing micro-organisms in a fluidized bed reactor. Microbiology, 142(8): 2187–2196
https://doi.org/10.1099/13500872-142-8-2187
33 E M van den Berg, M P Elisário, J G Kuenen, R Kleerebezem, M C M van Loosdrecht (2017). Fermentative bacteria influence the competition between denitrifiers and DNRA bacteria. Frontiers in Microbiology, 8: 1684
https://doi.org/10.3389/fmicb.2017.01684 pmid: 28928722
34 O Velasco-Garduño, A Mendoza-Reséndiz, C Fajardo-Ortiz, R Beristain-Cardoso (2019). Simultaneous ammonia and organic matter removal from industrial wastewater in a continuous novel hybrid carrousel bioreactor. International Journal of Environmental Science and Technology, 16(7): 3429–3436
https://doi.org/10.1007/s13762-018-2017-z
35 R Vinothkumar, J Y Dar, V S Bharti, A Singh, A Vennila, I A Bhat, P K Pandey (2021). Heterotrophic nitrifying and aerobic denitrifying bacteria: Characterization and comparison of shrimp pond and effluent discharge channel in aspects of composition and function. Aquaculture (Amsterdam, Netherlands), 539: 736659
https://doi.org/doi.org/10.1016/j.aquaculture.2021.736659
36 X Wang, R Yang, Y Guo, Z Zhang, C M Kao, S Chen (2019). Investigation of COD and COD/N ratio for the dominance of anammox pathway for nitrogen removal via isotope labelling technique and the relevant bacteria. Journal of Hazardous Materials, 366: 606–614
https://doi.org/10.1016/j.jhazmat.2018.12.036 pmid: 30576999
37 T C Yadav, A A Khardenavis, A Kapley (2014). Shifts in microbial community in response to dissolved oxygen levels in activated sludge. Bioresource Technology, 165: 257–264
https://doi.org/10.1016/j.biortech.2014.03.007 pmid: 24684815
38 C Yangin-Gomec, G Pekyavas, T Sapmaz, S Aydin, B Ince, Ç Akyol, O Ince (2017). Microbial monitoring of ammonia removal in a UASB reactor treating pre-digested chicken manure with anaerobic granular inoculum. Bioresource Technology, 241: 332–339
https://doi.org/10.1016/j.biortech.2017.05.070 pmid: 28577482
39 L Zhang, T L Hendrickx, C Kampman, H Temmink, G Zeeman (2013). Co-digestion to support low temperature anaerobic pretreatment of municipal sewage in a UASB-digester. Bioresource Technology, 148: 560–566
https://doi.org/10.1016/j.biortech.2013.09.013 pmid: 24080295
40 Y Zhang, Y Wang, Y Yan, H Han, M Wu (2019). Characterization of CANON reactor performance and microbial community shifts with elevated COD/N ratios under a continuous aeration mode. Frontiers of Environmental Science & Engineering, 13(1): 7
https://doi.org/10.1007/s11783-019-1095-6
[1] FSE-21112-OF-SS_suppl_1 Download
[1] Xiaoqiang Wang, Yanye Zhu, Yue Liu, Xiaole Weng, Zhongbiao Wu. Tailoring the simultaneous abatement of methanol and NOx on Sb-Ce-Zr catalysts via copper modification[J]. Front. Environ. Sci. Eng., 2022, 16(10): 130-.
[2] Yingwu Wang, Ping Ning, Ruheng Zhao, Kai Li, Chi Wang, Xin Sun, Xin Song, Qiang Lin. A Cu-modified active carbon fiber significantly promoted H2S and PH3 simultaneous removal at a low reaction temperature[J]. Front. Environ. Sci. Eng., 2021, 15(6): 132-.
[3] Lina Gan, Kezhi Li, Hejingying Niu, Yue Peng, Jianjun Chen, Yuandong Huang, Junhua Li. Simultaneous removal of NOx and chlorobenzene on V2O5/TiO2 granular catalyst: Kinetic study and performance prediction[J]. Front. Environ. Sci. Eng., 2021, 15(4): 70-.
[4] Jing Li, Haiqin Yu, Xue Zhang, Rixin Zhu, Liangguo Yan. Crosslinking acrylamide with EDTA-intercalated layered double hydroxide for enhanced recovery of Cr(VI) and Congo red: Adsorptive and mechanistic study[J]. Front. Environ. Sci. Eng., 2020, 14(3): 52-.
[5] Zhenfeng Han, Ying Miao, Jing Dong, Zhiqiang Shen, Yuexi Zhou, Shan Liu, Chunping Yang. Enhanced nitrogen removal and microbial analysis in partially saturated constructed wetland for treating anaerobically digested swine wastewater[J]. Front. Environ. Sci. Eng., 2019, 13(4): 52-.
[6] Yujiao Sun, Juanjuan Zhao, Lili Chen, Yueqiao Liu, Jiane Zuo. Methanogenic community structure in simultaneous methanogenesis and denitrification granular sludge[J]. Front. Environ. Sci. Eng., 2018, 12(4): 10-.
[7] Yi ZHAO,Tianxiang GUO,Zili ZANG. Activity and characteristics of “Oxygen-enriched” highly reactive absorbent for simultaneous flue gas desulfurization and denitrification[J]. Front. Environ. Sci. Eng., 2015, 9(2): 222-229.
[8] Shijian GE, Yongzhen PENG, Congcong LU, Shuying WANG. Practical consideration for design and optimization of the step feed process[J]. Front Envir Sci Eng, 2013, 7(1): 135-142.
[9] Zhaoxu PENG, Yongzhen PENG, Zhenbo YU, Xuliang LIU, Xiaoling LI, Randeng WANG. Control of sludge settleability and nitrogen removal under low dissolved oxygen condition[J]. Front Envir Sci Eng, 2012, 6(6): 884-891.
[10] LI Jun, GU Guowei, PENG Yongzhen, WEI Su. Factors affecting simultaneous nitrification and denitrification in an SBBR treating domestic wastewater[J]. Front.Environ.Sci.Eng., 2007, 1(2): 246-250.
[11] WANG Fang, YANG Fenglin, QI Aijiu. Nitrifying and denitrifying bacteria in aerobic granules formed in sequencing batch airlift reactors[J]. Front.Environ.Sci.Eng., 2007, 1(2): 184-189.
[12] ZHANG Peng, ZHOU Qi. Simultaneous nitrification and denitrification in activated sludge system under low oxygen concentration[J]. Front.Environ.Sci.Eng., 2007, 1(1): 49-52.
Viewed
Full text


Abstract

Cited
  Shared   
  Discussed