scholarly journals The Operating Characteristics of Partial Nitrification by Controlling pH and Alkalinity

Water ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 286
Author(s):  
Chen Chen ◽  
Yinghao Song ◽  
Yanchao Yuan
Keyword(s):  
Dissolved Oxygen ◽  
Batch Reactor ◽  
Nitrogen Concentration ◽  
Partial Nitrification ◽  
Nitrifying Bacteria ◽  
Nitrite Accumulation ◽  
Ammonia Oxidizing Bacteria ◽  
Operating Characteristics ◽  
Ph Change ◽  
Accumulation Efficiency

In many experiments, a partial nitrification device is initiated with the use of highly active nitrating sludge because of the large number of nitrifying bacteria. Ammonia-oxidizing bacteria (AOB) are more adaptable to low-dissolved oxygen environments than nitrite-oxidizing bacteria (NOB). NOB activity was inhibited when the dissolved oxygen (DO) levels were decreased, causing the nitrate-nitrogen concentration to gradually decrease in the effluent and the nitrite-nitrogen concentration to gradually increase, achieving the accumulation of nitrous nitrogen. In this experiment, a sequencing batch reactor (SBR) was used to suppress NOB activity at a given pH while maintaining DO at a very low level so that the ammonia–water reaction mainly occurred in the device, and then the mud and water separated. Compared with other experiments, this approach can occur in 25 days, and it runs stably for more than two months until the device closes when the ammonia-nitrogen concentration is about 170 mg/L. This experiment also compared the difference between the pH change at the beginning of the device operation and after the device was stable. In order to increase the efficiency of bacterial appreciation, supplementing NaHCO3 increased the HCO3− concentration by 300 mg/L on the 25th day. It was found that some nitrification reactions still occurred, but they were not enough to destabilize the device. The nitrosate accumulation efficiency still gradually increased, and the average nitrite accumulation efficiency was 87.25% after NaHCO3 supplementation.

Partial Nitrification to Nitrite with Real-Time Aeration Duration Control in an SBR Treating Domestic Wastewater

2011 ◽  
Vol 356-360 ◽  
pp. 1046-1049 ◽  
Author(s):  
Yu Chen ◽  
Jun Li ◽  
C .W Wang ◽  
X.F Zhao ◽  
B.H Zhao
Keyword(s):  
Real Time ◽  
Batch Reactor ◽  
Domestic Wastewater ◽  
Partial Nitrification ◽  
Nitrite Accumulation ◽  
Ammonia Oxidizing Bacteria ◽  
Term Operation ◽  
Nitrite Oxidizing Bacteria ◽  
Low Strength

Sustainable partial nitrification to nitrite has been proven difficult in treating low strength nitrogenous wastewater. Real-time aeration duration control was used to achieve efficient partial nitrification to nitrite in a sequencing batch reactor (SBR) to treat low strength domestic wastewater. Above 95% nitrite accumulation ratio was maintained for long-term operation at normal condition. Partial nitrification established by controlling aeration duration showed good performance and robustness even though some time encountering long-term extended aeration. Process control enhanced the successful accumulation of ammonia oxidizing bacteria (AOB) and washout of nitrite oxidizing bacteria (NOB).

scholarly journals Light as a Novel Inhibitor of Nitrite-Oxidizing Bacteria (NOB) for the Mainstream Partial Nitrification of Wastewater Treatment

Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 346
Author(s):  
Keugtae Kim ◽  
Yong-Gyun Park
Keyword(s):  
Wastewater Treatment ◽  
Blue Light ◽  
Nitrogen Removal ◽  
Municipal Wastewater ◽  
Partial Nitrification ◽  
Biological Nutrient Removal ◽  
Nitrite Accumulation ◽  
Light Illumination ◽  
Ammonia Oxidizing Bacteria ◽  
Nitrite Oxidizing Bacteria

Conventional biological nutrient removal processes in municipal wastewater treatment plants are energy-consuming, with oxygen supply accounting for 45–75% of the energy expenditure. Many recent studies examined the implications of the anammox process in sidestream wastewater treatment to reduce energy consumption, however, the process did not successfully remove nitrogen in mainstream wastewater treatment with relatively low ammonia concentrations. In this study, blue light was applied as an inhibitor of nitrite-oxidizing bacteria (NOB) in a photo sequencing batch reactor (PSBR) containing raw wastewater. This simulated a biological nitrogen removal system for the investigation of its application potential in nitrite accumulation and nitrogen removal. It was found that blue light illumination effectively inhibited NOB rather than ammonia-oxidizing bacteria due to their different sensitivity to light, resulting in partial nitrification. It was also observed that the NOB inhibition rates were affected by other operational parameters like mixed liquor suspended solids (MLSS) concentration and sludge retention time (SRT). According to the obtained results, it was concluded that the process efficiency of partial nitrification and anammox (PN/A) could be significantly enhanced by blue light illumination with appropriate MLSS concentration and SRT conditions.

Efficient and integrated start-up strategy for partial nitrification to nitrite treating low C/N domestic wastewater

2009 ◽  
Vol 60 (12) ◽  
pp. 3243-3251 ◽  
Author(s):  
Jianhua Guo ◽  
Shuying Wang ◽  
Huijun Huang ◽  
Yongzhen Peng ◽  
Shijian Ge ◽  
...  
Keyword(s):  
Domestic Wastewater ◽  
Kinetic Mechanism ◽  
Partial Nitrification ◽  
Nitrifying Bacteria ◽  
Nitrite Accumulation ◽  
Fish Analysis ◽  
Batch Reactors ◽  
Sequencing Batch Reactors ◽  
Start Up ◽  
Operation Results

Nitrogen removal via the nitrite pathway has the potential of reducing the requirements for aeration consumption and carbon source. However, the development of an efficient and quick start-up strategy for partial nitrification to nitrite has proven difficult in the treatment of low strength wastewater. In this study, the feasibility of partial nitrification achieved by using real-time aeration duration control was not only demonstrated from the kinetic mechanism, but also was validated in three sequencing batch reactors (SBRs) fed with low C/N domestic wastewater. Nitrite accumulation could be achieved when aeration was terminated as soon as an inflexion pH point was reached (the dpH/dt became from negative to positive). The reduction or limitation of the NOB growth could be achieved through aeration duration control, due to leaving no extra time for NOB to convert the accumulated nitrite. The experimental operation results also showed that partial nitrification with nitrite accumulation ratios of over 80% was achieved successfully in these three reactors with process control. Fluorescence in situ hybridization (FISH) analysis indicated the reduction of NOB was achieved and AOB became the dominant nitrifying bacteria. Moreover, an integrated start-up strategy based on aeration duration control was proposed to quickly achieve partial nitrification to nitrite.

Partial nitrification of non-ammonium-rich wastewater within biofilm filters under ambient temperature

2010 ◽  
Vol 62 (7) ◽  
pp. 1518-1525 ◽  
Author(s):  
Hongyu Wang ◽  
Jiajie He ◽  
Kai Yang
Keyword(s):  
Activated Carbon ◽  
Room Temperature ◽  
Partial Nitrification ◽  
Nitrifying Bacteria ◽  
Ammonia Oxidizing Bacteria ◽  
Filtration Process ◽  
Porous Flow ◽  
Activated Carbon Filter ◽  
Carbon Filter ◽  
Filter Layer

This study evaluated the partial nitrification performances of two biofilm filters over a synthetic non-ammonium-rich wastewater at a 20°C room temperature under both limited DO (∼2.0 mg/L) and unlimited DO (∼4.0 mg/L) conditions. The two filters were each of 80 cm long and used different biofilm carriers: activated carbon and ceramic granule. Results showed that partial nitrification was accomplished for both filters under the limited DO condition. However, the effluent NO2-N was higher in the ceramic granule filter than in the activated carbon filter, and was less susceptible to the influent COD/N changes. Further investigation into the water phase COD and NH4-N depth profiles and bacteria population within the two filters showed that by putting upper filter layer (upstream) to confront relatively higher influent COD/N ratios, the filtration process naturally put lower filter layers (downstream) relatively more favorable for nitrifying bacteria (ammonia oxidizing bacteria in this study) to prosper, making the filter depth left for nitrification a crucial factor for the effectiveness of nitrification with a filter. The potentially different porous flow velocities of the two filters might be the reason to cause their different partial nitrification performances, with a lower porous flow velocity (the ceramic granule filter) favoring partial nitrification more. In summation, DO, filter depth, and filtration speed should be played together to successfully operate a biofilm filter for partial nitrification.

Influence of dissolved oxygen concentration on the start-up of the anammox-based process: ELAN®

2015 ◽  
Vol 72 (4) ◽  
pp. 520-527 ◽  
Author(s):  
N. Morales ◽  
A. Val del Río ◽  
J. R. Vázquez-Padín ◽  
R. Gutiérrez ◽  
R. Fernández-González ◽  
...  
Keyword(s):  
Dissolved Oxygen ◽  
Removal Rate ◽  
Batch Reactor ◽  
Thick Layer ◽  
Average Diameter ◽  
Bulk Liquid ◽  
Anammox Bacteria ◽  
Total Biomass ◽  
Ammonia Oxidizing Bacteria ◽  
Anaerobic Digester Supernatant

The anammox-based process ELAN® was started-up in two different sequencing batch reactor (SBR) pilot plant reactors treating municipal anaerobic digester supernatant. The main difference in the operation of both reactors was the dissolved oxygen (DO) concentration in the bulk liquid. SBR-1 was started at a DO value of 0.4 mg O2/L whereas SBR-2 was started at DO values of 3.0 mg O2/L. Despite both reactors working at a nitrogen removal rate of around 0.6 g N/(L d), in SBR-1, granules represented only a small fraction of the total biomass and reached a diameter of 1.1 mm after 7 months of operation, while in SBR-2 the biomass was mainly composed of granules with an average diameter of 3.2 mm after the same operational period. Oxygen microelectrode profiling revealed that granules from SBR-2 where only fully penetrated by oxygen with DO concentrations of 8 mg O2/L while granules from SBR-1 were already oxygen penetrated at DO concentrations of 1 mg O2/L. In this way granules from SBR-2 performed better due to the thick layer of ammonia oxidizing bacteria, which accounted for up to 20% of all the microbial populations, which protected the anammox bacteria from non-suitable liquid media conditions.

Achieving nitrogen removal via nitrite pathway from urban landfill leachate using the synergetic inhibition of free ammonia and free nitrous acid on nitrifying bacteria activity

2013 ◽  
Vol 68 (9) ◽  
pp. 2035-2041 ◽  
Author(s):  
H. W. Sun ◽  
Y. Bai ◽  
Y. Z. Peng ◽  
H. G. Xie ◽  
X. N. Shi
Keyword(s):  
Landfill Leachate ◽  
Biological System ◽  
Nitrous Acid ◽  
Free Ammonia ◽  
Nitrifying Bacteria ◽  
Anaerobic Sludge ◽  
Nitrite Accumulation ◽  
Fish Analysis ◽  
Ammonia Oxidizing Bacteria ◽  
Free Nitrous Acid

In this study, a biological system consisting of an up-flow anaerobic sludge blanket (UASB) and anoxic–oxic (A/O) reactor was established for the advanced treatment of high ammonium urban landfill leachate. The inhibitory effect of free ammonia (FA) and free nitrous acid (FNA) on the nitrifying bacterial activity was used to achieve stable nitritation in the A/O reactor. The results demonstrated that the biological system achieved chemical oxygen demand (COD), total nitrogen (TN) and NH4+-N removal efficiencies of 95.3, 84.6 and 99.2%, respectively at a low carbon-to-nitrogen ratio of 3:1. Simultaneous denitritation and methanogenesis in the UASB could improve the removal of COD and TN. Nitritation with above 90% nitrite accumulation was successfully achieved in the A/O reactor by synergetic inhibition of FA and FNA on the activity of nitrite oxidizing bacteria (NOB). Fluorescence in situ hybridization (FISH) analysis showed that ammonia oxidizing bacteria (AOB) was dominant and was considered to be responsible for the satisfactory nitritation performance.

Effect of dissolved oxygen concentration on the biofilm and in situ analysis by fluorescence in situ hybridization (FISH) and microelectrodes

2003 ◽  
Vol 47 (1) ◽  
pp. 49-57 ◽  
Author(s):  
A. Jang ◽  
P.L. Bishop ◽  
S. Okabe ◽  
S.G. Lee ◽  
I.S. Kim
Keyword(s):  
In Situ Hybridization ◽  
Dissolved Oxygen ◽  
Nitrifying Bacteria ◽  
Dry Density ◽  
Ammonia Oxidizing Bacteria ◽  
Biofilm Thickness ◽  
Experimental Findings ◽  
And Control ◽  
Microelectrode Measurements

A better understanding of microbiology and ecology of nitrifying bacteria in inner biofilms is an important part of improving process performance and control. Microelectrodes and fluorescent in situ hybridization (FISH) in biofilm research have been used to investigate the spatial distributions of various microbial activities in biofilms and have led to new experimental findings as well as modifications of the homogeneous assumptions in the biofilm kinetic models. The objective of this study is to try the combination of two methods, both FISH and microelectrode measurements, and to provide reliable and in situ information on nitrifying bacterial activity in biofilms. The characteristics of biofilm developed on tygon slides were different according to the change of dissolved oxygen (DO). When the DO increased from 2 to 10 μg DO/L, the rate of the biofilm thickness increased and its dry density changed from 50-70 to 25-90 mg/cm3. Ammonia oxidizing bacteria were not uniformly distributed in biofilm, and were found at the deeper layer where oxygen is depleted, they were detected primarily in the upper and middle layers of the biofilm.

Comparison of partial nitrification to nitrite for ammonium-rich organic wastewater in sequencing batch reactors and continuous stirred-tank reactor at laboratory-scale

2009 ◽  
Vol 60 (11) ◽  
pp. 2861-2868 ◽  
Author(s):  
J. Yan ◽  
Y. Y. Hu
Keyword(s):  
Batch Reactor ◽  
Partial Nitrification ◽  
Stirred Tank ◽  
Nitrite Accumulation ◽  
Continuous Stirred Tank Reactor ◽  
Stirred Tank Reactor ◽  
Tank Reactor ◽  
Two Systems ◽  
Continuous Stirred Tank ◽  
Organic Wastewater

The combined partial nitrification/Anammox process is especially suitable for the treatment of influents with low C/N ratio. However, many nitrogenous wastewater are also rich in organics. Two systems (continuous stirred-tank reactor (CSTR) and sequencing batch reactor (SBR)) are commonly used to achieve nitrite accumulation, but no complete comparison between these two systems for treating different wastewater has been reported. The objective of this paper was to compare the partial nitrification in CSTR and SBR for the treatment of ammonium-rich organic wastewater. The result showed that it took a shorter time to startup partial nitrification in CSTR, but SBR was a better option for treating ammonium-rich organic wastewater with C/N lower than 0.34. With increase HRT to 48 h, excellent nitrite accumulation could be achieved in both reactors for wastewater containing landfill leachate. For subsequent anammox, CSTR was more suitable when leachate percentage ranged from 35% to 40%.

Study on Achievement and Temperature Influence of Shortcut Nitrification in Sequencing Biofilm Batch Reactor

2014 ◽  
Vol 955-959 ◽  
pp. 3389-3392
Author(s):  
Li Cheng Zhang ◽  
Wei Dang ◽  
Jie Li ◽  
Jun Sui
Keyword(s):  
Accumulation Rate ◽  
Batch Reactor ◽  
Biofilm Reactor ◽  
Nitrite Accumulation ◽  
Ammonia Oxidizing Bacteria ◽  
Temperature Influence ◽  
Intermittent Aeration ◽  
Urban Sewage ◽  
Sequencing Batch Biofilm Reactor ◽  
Start Up

The intermittent aeration strategy was applied to the sequencing batch biofilm reactor (SBBR) for the enhanced treatment of urban sewage. Ammonia oxidizing bacteria was cultivated by inoculation. After 25 days cultivation shortcut nitrification was successfully achieved and nitrite accumulation rate could be up to 93%. In the start-up phase of shortcut nitrification, intermittent aeration could increase production of nitrite and promote the enrichment of ammonia oxidizing bacteria. It was concluded that temperature could affect nitrite accumulation. When temperature is in 25~35°C, the nitrite accumulation rate could be up to 90%.

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