Application of a synthetic zeolite as a storage medium in SBRs to achieve the stable partial nitrification of ammonium

2019 ◽  
Vol 5 (2) ◽  
pp. 287-295 ◽  
Author(s):  
Jing Chen ◽  
Xiaojun Wang ◽  
Zhenguo Chen ◽  
Xinghui Feng ◽  
Xiaokun Chen

Free ammonia (FA) is the growth substrate for ammonia-oxidizing bacteria (AOB), but a high concentration of FA could also inhibit AOB activities.

2004 ◽  
Vol 50 (6) ◽  
pp. 31-36 ◽  
Author(s):  
Y.Z. Peng ◽  
Y.Z. Li ◽  
C.Y. Peng ◽  
S.Y. Wang

In this study, laboratory-scale experiments were conducted applying a Sequencing Batch Reactor (SBR) activated sludge process to a wastewater stream from a pharmaceutical factory. Nitrogen removal can be achieved via partial nitrification and denitrification and the efficiency was above 99% at 23°C ± 1. The experimental results indicated that the nitrite oxidizers were more sensitive than ammonia oxidizers to the free ammonia in the wastewater. The average accumulation rate of nitrite was much higher than that of nitrate. During nitrogen removal via the nitrite pathway, the end of nitrification and denitrification can be exactly decided by monitoring the variation of pH. Consequently, on-line control for nitrogen removal from the pharmaceutical manufacturing wastewater can be achieved and the cost of operation can be reduced.


Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 346
Author(s):  
Keugtae Kim ◽  
Yong-Gyun Park

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.


2010 ◽  
Vol 62 (7) ◽  
pp. 1518-1525 ◽  
Author(s):  
Hongyu Wang ◽  
Jiajie He ◽  
Kai Yang

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.


2013 ◽  
Vol 68 (9) ◽  
pp. 2035-2041 ◽  
Author(s):  
H. W. Sun ◽  
Y. Bai ◽  
Y. Z. Peng ◽  
H. G. Xie ◽  
X. N. Shi

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.


2020 ◽  
Vol 7 (9) ◽  
pp. 200584
Author(s):  
Kai Zhang ◽  
Zhaozhao Wang ◽  
Mengxia Sun ◽  
Dongbo Liang ◽  
Liangang Hou ◽  
...  

In this study, a membrane bioreactor (MBR) was used to achieve both nitrogen and carbon removal by a simultaneous partial nitrification, anammox and denitrification (SNAD) process. During the entire experiment, the intermittent aeration (non-aerobic time : aeration time, min min −1 ) cycle was controlled by a time-controlled switch, and the aeration rate was controlled by a gas flowmeter, and the optimal operating parameters as determined by response surface methodology (RSM) were a C/N value of 1.16, a DO value of 0.84 mg l −1 and an aerobic time ( T ae ) of 15.75 min. Under these conditions, the SNAD process achieved efficient and stable nitrogen and carbon removal; the total inorganic nitrogen removal efficiency and chemical oxygen demand removal efficiency were 92.31% and 95.67%, respectively. With the formation of granular sludge, the membrane fouling rate decreased significantly from 35.0 Pa h −1 at SNAD start-up to 19.9 Pa h −1 during stable operation. Fluorescence in situ hybrid analyses confirmed the structural characteristics and the relative ratio of aerobic ammonia-oxidizing bacteria, anaerobic ammonia-oxidizing bacteria and denitrifying bacteria in the SNAD system.


2020 ◽  
Author(s):  
Patricia Perez ◽  
Emily Clements ◽  
Cristian Picioreanu ◽  
Robert nerenberg

<p>The membrane aerated biofilm reactor (MABR) is an emerging wastewater treatment technology that can greatly decrease energy requirements for wastewater treatment. It consists of cassettes of air-supplying, hollow-fiber membranes that can retrofit existing activated sludge processes. MABR behavior differs from conventional biofilm processes due to the counter-diffusion of the electron donor (ammonia) and acceptor (oxygen).</p> <p> </p> <p>Partial nitrification (PN), or partial nitrification Anammox (PNA), can further improve MABR energy efficiency and cost effectiveness.  To achieve this, ammonia oxidizing bacteria (AOB) must outcompete nitrite-oxidizing bacteria (NOB).  High temperatures favor AOB, but it is not feasible to heat the wastewater influent.  However, high-temperature compressed air can be supplied to the membrane lumen, increasing temperatures inside the biofilm without increasing the bulk temperatures. No previous research has addressed temperature gradients in biofilms, which can lead to gradients in  biodegradation kinetics, diffusivities, and O<sub>2</sub> solubility.</p> <p> </p> <p>The objective of this research was to explore the effect of temperature gradients in MABR biofilms, especially with respect to PN. We used a one-dimensional multi-species biofilm model, which considers the MABR physical and biochemical behavior, especially with respect to temperature. The model was implemented using COMSOL Multiphysics. We also used bench-scale experiments to explore the effect of biofilm temperature gradients on MABR nitrification and PN performances and microbial community structure.</p> <p> </p> <p>Model simulations showed that MABR biofilms exposed to a temperature gradient from 20 ºC (biofilm interior) to 10 ºC (bulk liquid) had a 60% increase in nitrification rates compared with biofilms at 10 ºC. More importantly, the model predicted a complete out competition of NOBs within the biofilm.</p> <p> </p> <p>Preliminary experimental results confirm a significant (105%) increase in nitrification fluxes with a temperature of 30ºC compared to ambient temperatures (20ºC). Future experiments will validate the model predicted effects of biofilm temperature gradients on nitrification fluxes and microbial community structure.</p>


2010 ◽  
Vol 61 (12) ◽  
pp. 3008-3016 ◽  
Author(s):  
J. Claros ◽  
E. Jiménez ◽  
L. Borrás ◽  
D. Aguado ◽  
A. Seco ◽  
...  

A continuously aerated SHARON (single reactor high activity ammonia removal over nitrite) system has been operated to achieve partial nitritation. Two sets of batch experiments were carried out to study the effect of ammonia concentration and salinity on the activity of ammonia-oxidizing bacteria (AOB). Activity of AOB raised as free ammonia concentration was increased reaching its maximum value at 4.5 mg NH3-N l−1. The half saturation constant for free ammonia was determined (KNH3 = 0.32 mg NH3-N l−1). Activity decreased at TAN (total ammonium–nitrogen) concentration over 2,000 mg NH4-N l−1. No free ammonia inhibition was detected. The effect of salinity was studied by adding different concentrations of different salts to the biomass. No significant differences were observed between the experiments carried out with a salt containing or not containing NH4. These results support that AOB are inhibited by salinity, not by free ammonia. A mathematical expression to represent this inhibition is proposed. To compare substrate affinity and salinity inhibitory effect on different AOB populations, similar experiments were carried out with biomass from a biological nutrient removal pilot plant. The AOB activity reached its maximum value at 0.008 mg NH3-N l−1 and decreased at TAN concentration over 400 mg NH4-N l−1. These differences can be explained by the different AOB predominating species: Nitrosomonas europaea and N. eutropha in the SHARON biomass and Nitrosomonas oligotropha in the pilot plant.


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