N2O emission in short-cut simultaneous nitrification and denitrification process: dynamic emission characteristics and succession of ammonia-oxidizing bacteria

2014 ◽  
Vol 69 (12) ◽  
pp. 2541-2547 ◽  
Author(s):  
Yingyan Yan ◽  
Ping Li ◽  
Jinhua Wu ◽  
Nengwu Zhu ◽  
Pingxiao Wu ◽  
...  
Keyword(s):  
Removal Rate ◽  
N2o Emission ◽  
Nitrite Accumulation ◽  
Ammonia Oxidizing Bacteria ◽  
Simultaneous Nitrification And Denitrification ◽  
Process Dynamic ◽  
Nitrifier Denitrification ◽  
Important Pathway ◽  
Nitrification And Denitrification ◽  
Denitrification Process

A sequencing batch airlift reactor was used to investigate the characteristics of nitrous oxide (N2O) emission and the succession of an ammonia-oxidizing bacteria (AOB) community. The bioreactor could successfully switch from the complete simultaneous nitrification and denitrification (SND) process to the short-cut SND process by increasing the influent pH from 7.0–7.3 to 8.0–8.3. The results obtained showed that, compared with the complete SND process, the TN removal rate and SND efficiency were improved in the short-cut SND process by approximately 13 and 11%, respectively, while the amount of N2O emission was nearly three times larger than that in the complete SND process. The N2O emission was closely associated to nitrite accumulation. Analysis of the AOB microbial community showed that nitrifier denitrification by Nitrosomonas-like AOB could be an important pathway for the enhancement of N2O emission in the short-cut SND process.

Effect of Carbon Nitrogen Ratio on Simultaneous Nitrification and Denitrification via Nitrite Technology in Sequencing Batch Biofilm Reactor and the Process Control

2013 ◽  
Vol 777 ◽  
pp. 232-237 ◽  
Author(s):  
Hui Wei Zhao ◽  
Ke Fang Zhang ◽  
Hong Wei Rong ◽  
Chao Sheng Zhang ◽  
Zhi Wen Yang
Keyword(s):  
Process Control ◽  
Removal Efficiency ◽  
Removal Rate ◽  
Control Point ◽  
Biofilm Reactor ◽  
Nitrite Accumulation ◽  
Simultaneous Nitrification And Denitrification ◽  
Carbon Nitrogen Ratio ◽  
Nitrogen Ratio ◽  
Nitrification And Denitrification

This study aimed to evaluate the effect of carbon nitrogen ratio (COD/N) on simultaneous nitrification and denitrification (SND) via nitrite technology in SBBR and the process control. Under the condition of different C/N ratios respectively 1.8, 3.6, 7,5,11.1 and 13.7, the various indices of the removal efficiency in the system and DO, ORP, and pH in the process of reaction were investigated. The C/N ratio was found to be an important limiting factor for SBBR simultaneous nitrification and denitrification via nitrite process. After integrating the factor of energy consumption and removal efficiency, we obtained that the optimum C/N ratios control range from 7.5 to 11.1, reaction time was between 225 min and 315 min, nitrite accumulation rate was between 72.83 % and 78.7 %, COD removal rate was between 92.31 % and 93.08 %, the total nitrogen removal rate was between 81.0 % and 85.86 %. For steady-state simultaneous nitrification and denitrification via nitrite process in SBBR, the jump point (C) on the DO, pH and ORP curve at reaction later period can be used as a control point to indicate the end of the reaction.

Simultaneous nitrification and denitrification in biofilters with real time aeration control

2001 ◽  
Vol 43 (1) ◽  
pp. 269-276 ◽  
Author(s):  
N. Puznava ◽  
M. Payraudeau ◽  
D. Thornberg
Keyword(s):  
Real Time ◽  
Nitrogen Removal ◽  
Simultaneous Nitrification And Denitrification ◽  
Biological Aerated Filter ◽  
Diffusion Effect ◽  
Different Depths ◽  
Nitrification And Denitrification ◽  
Aerated Filter ◽  
Denitrification Process ◽  
Aeration Control

The aim of this article is to present a new biological aerated filter (BAF) for nitrogen removal based on simultaneous nitrification and denitrification. Contrary to the systems which integrate both an aerated and a non-aerated zone to allow complete nitrogen removal in one compact or two different units (pre-denitrification and nitrification), this upflow BAF system is based on the principle of simultaneous nitrification and denitrification since the filter is completely aerated. The denitrification process is possible due to the diffusion effect which dominates biofilm processes. The real time aeration control allows us to maintain a low dissolved oxygen value (0.5 to 3 mg O2/l). In this case, the biofilm will not be fully (or less) penetrated with oxygen and denitrification will be carried out in a large part of the biofilm. Therefore, nitrification and denitrification is running simultaneously in different depths of the biofilm. By using 50% less air this BAF gave the same results (less than 20mg TN/l) on pilot plant as a classical nitrification and denitrification BAF (Toettrup et al., 1994). Less recirculation was necessary to achieve the same denitrification.

Rapid start-up of a nitrifying reactor using aerobic granular sludge as seed sludge

2012 ◽  
Vol 65 (3) ◽  
pp. 581-588 ◽  
Author(s):  
Naohiro Kishida ◽  
Goro Saeki ◽  
Satoshi Tsuneda ◽  
Ryuichi Sudo
Keyword(s):  
Removal Rate ◽  
Granular Sludge ◽  
Ammonia Removal ◽  
High Rate ◽  
Aerobic Granular Sludge ◽  
Nitrite Accumulation ◽  
Ammonia Oxidizing Bacteria ◽  
Continuous Stirred Tank Reactor ◽  
Start Up ◽  
Seed Sludge

In this study, the effectiveness of aerobic granular sludge as seed sludge for rapid start-up of nitrifying processes was investigated using a laboratory-scale continuous stirred-tank reactor (CSTR) fed with completely inorganic wastewater which contained a high concentration of ammonia. Even when a large amount of granular biomass was inoculated in the reactor, and the characteristics of influent wastewater were abruptly changed, excess biomass washout was not observed, and biomass concentration was kept high at the start-up period due to high settling ability of the aerobic granular sludge. As a result, an ammonia removal rate immediately increased and reached more than 1.0 kg N/m3/d within 20 days and up to 1.8 kg N/m3/d on day 39. Subsequently, high rate nitritation was stably attained during 100 days. However, nitrite accumulation had been observed for 140 days before attaining complete nitrification to nitrate. Fluorescence in situ hybridization analysis revealed the increase in amount of ammonia-oxidizing bacteria which existed in the outer edge of the granular sludge during the start-up period. This microbial ecological change would make it possible to attain high rate ammonia removal.

Simultaneous nitrification and denitrification in a single reactor using bio-electrochemical process

2002 ◽  
Vol 46 (4-5) ◽  
pp. 163-169 ◽  
Author(s):  
T. Watanabe ◽  
S. Hashimoto ◽  
M. Kuroda
Keyword(s):  
Electric Current ◽  
Fixed Effects ◽  
Removal Rate ◽  
Electrochemical Process ◽  
Hydrogen Gas ◽  
High Rate ◽  
Bulk Solution ◽  
Simultaneous Nitrification And Denitrification ◽  
Do Concentration ◽  
Nitrification And Denitrification

Feasibility of a bio-electrochemical process for simultaneous nitrification and denitrification in a single reactor was experimentally investigated. The reactor consisted of anodic and cathodic electrodes, on which nitrifying and denitrifying biofilms, respectively, were fixed. Effects of the applied electric current and DO concentration in the bulk solution were examined. The TN removal could be achieved through the occurrence of nitrification and denitrification in anodic and cathodic biofilms, respectively. Both nitrification and denitrification rates increased with an increase in the applied electric current. Even at low DO concentration in the bulk solution, nitrification proceeded at a high rate by utilizing oxygen generated on the anode. Denitrification rate remained relatively high at high DO concentration due to supplying hydrogen gas to the inner side of the cathodic biofilm. The higher TN removal rate tended to be obtained at lower DO concentration and higher current density. From these results, it was concluded that the bio-electrochemical process was applicable to simultaneous nitrification and denitrification due to stable formation of aerobic and anoxic regions in the single reactor.

scholarly journals Efficient nitrification and low N2O emission in a weakly acidic bioreactor at low dissolved oxygen levels are due to comammox

2021 ◽  
Author(s):  
Deyong Li ◽  
Fang Fang ◽  
Guoqiang Liu
Keyword(s):  
Wastewater Treatment ◽  
Dissolved Oxygen ◽  
Greenhouse Gas ◽  
N2o Emission ◽  
Low Energy ◽  
Emission Source ◽  
Ammonia Oxidizer ◽  
Ammonia Oxidizing Bacteria ◽  
Nitrifier Denitrification ◽  
Low Do

Nitrification is an essential process for nutrient removal from wastewater and an important emission source of nitrous-oxide (N2O), which is a powerful greenhouse gas and a dominant ozone-depleting substance. In this study, nitrification and N2O emissions were tested in two weakly acidic (pH = 6.3–6.8) reactors: one with dissolved oxygen (DO) over 2.0 mg/L and the other with DO approximately 0.5 mg/L. Efficient nitrification was achieved in both reactors. Compared to the high-DO reactor, N2O emission in the low-DO reactor decreased slightly by 20% and had insignificant correlation with the fluctuations of DO (P = 0.935) and nitrite (P = 0.713), indicating that N2O might not be mainly produced via nitrifier denitrification. Based on qPCR, qFISH, functional gene amplicon and metagenome sequencing, it was found that complete ammonia oxidizer (comammox) Nitrospira significantly outnumbered canonical ammonia-oxidizing bacteria (AOB) in both weakly acidic reactors, especially in the low DO reactor with the comammox/AOB amoA gene ratio increasing from 6.6 to 17.1. Therefore, it was speculated that the enriched comammox was the primary cause for the slightly decreased N2O emission under long-term low DO in weakly acidic reactor. This study demonstrated that comammox Nitrospira can survive well under the weakly acidic and low-DO conditions, implying that achieving efficient nitrification with low N2O emission as well as low energy and alkalinity consumption is feasible for wastewater treatment. Importance Nitrification in wastewater treatment is an important process for eutrophication control and an emission source for greenhouse gas of N2O. The nitrifying process is usually operated at a slightly alkaline pH and high DO (>2 mg/L) to ensure efficient nitrification. However, it consumes a large amount of energy and chemicals especially for wastewater without sufficient alkalinity. This manuscript demonstrated that comammox can adapt well to the weakly acidic and low-DO bioreactors, with a result of efficient nitrification and low N2O emission. These findings indicate that comammox are significant for sustainable wastewater treatment, which provides an opportunity to achieve efficient nitrification with low N2O production as well as low energy and chemical consumption simultaneously.

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