Influence of extracellular polymeric substances on nitrogen removal in an intermittently-aerated membrane bioreactor

2005 ◽  
Vol 51 (11) ◽  
pp. 151-158 ◽  
Author(s):  
H. Nagaoka ◽  
H. Nemoto
Keyword(s):  
Molecular Weight ◽  
Nitrogen Removal ◽  
Extracellular Polymeric Substances ◽  
Removal Rate ◽  
Membrane Surface ◽  
Synthetic Wastewater ◽  
Nitrifying Bacteria ◽  
Gel Chromatography ◽  
Bacterial Cells ◽  
Intermittent Aeration

Influence of EPS on fouling of intermittent aeration MBR reactor (denitrification MBR) was investigated changing intermittent aeration cycle (10 minute-cycle and 120 minute-cycle) in laboratory-scale reactors using synthetic wastewater. EPS were extracted from bacterial cells using cation resin method and molecular weight fractioning of EPS was conducted using gel chromatography. In both of the reactors, nitrogen removal rate was almost 100% after 50th day although DO concentration was not very high during the aerated phase because of accumulation of nitrifying bacteria in the reactors. In the 120 minutes-cycle reactor, trans-membrane pressure increased more rapidly than in the 10 minutes-cycle reactor. The reason might be that EPS of more than 1000 kDa, which are the main fouling substances, are produced more rapidly in the 120 minute-cycle condition. It was also found that three peaks at around 100 kDa, 500 kDa and 2000 kDa are prominent in EPS in intermittent-aeration MBR irrespective of cycle and higher molecular weight EPS are decomposed to smaller molecular weight EPS on membrane surface.

Effects of chemical oxygen demand (COD)/N ratios on pollutants removal in the subsurface wastewater infiltration systems with/without intermittent aeration

2016 ◽  
Vol 73 (11) ◽  
pp. 2662-2669 ◽  
Author(s):  
Siyu Song ◽  
Jing Pan ◽  
Shiwei Wu ◽  
Yijing Guo ◽  
Jingxiao Yu ◽  
...  
Keyword(s):  
Chemical Oxygen Demand ◽  
Nitrogen Removal ◽  
Removal Rate ◽  
Oxygen Deficiency ◽  
Oxygen Demand ◽  
Ammonia Nitrogen ◽  
Intermittent Aeration ◽  
Oxidation Reduction ◽  
The Matrix ◽  
Pollutants Removal

The matrix oxidation reduction potential level, organic pollutants and nitrogen removal performances of eight subsurface wastewater infiltration systems (SWISs) (four with intermittent aeration, four without intermittent aeration) fed with influent chemical oxygen demand (COD)/N ratio of 3, 6, 12 and 18 were investigated. Nitrification of non-aerated SWISs was poor due to oxygen deficiency while higher COD/N ratios further led to lower COD and nitrogen removal rate. Intermittent aeration achieved almost complete nitrification, which successfully created aerobic conditions in the depth of 50 cm and did not change anoxic or anaerobic conditions in the depth of 80 and 110 cm. The sufficient carbon source in high COD/N ratio influent greatly promoted denitrification in SWISs with intermittent aeration. High average removal rates of COD (95.68%), ammonia nitrogen (NH4+-N) (99.32%) and total nitrogen (TN) (89.65%) were obtained with influent COD/N ratio of 12 in aerated SWISs. The results suggest that intermittent aeration was a reliable option to achieve high nitrogen removal in SWISs, especially with high COD/N ratio wastewater.

scholarly journals Nitrogen removal from ammonium-contaminated groundwater using dropping nitrification–cotton-based denitrification reactor

2021 ◽  
Author(s):  
A. K. Maharjan ◽  
K. Mori ◽  
K. Nishida ◽  
T. Toyama
Keyword(s):  
Nitrogen Removal ◽  
Removal Rate ◽  
Denitrifying Bacteria ◽  
Electron Donors ◽  
Nitrifying Bacteria ◽  
Contaminated Groundwater ◽  
Total N ◽  
N Removal ◽  
Denitrification Reactor ◽  
Synthetic Groundwater

Abstract A novel dropping nitrification–cotton-based denitrification reactor was developed for total nitrogen (N) removal from ammonium (NH4+)-contaminated groundwater. The nitrogen removal ability of the reactor was evaluated for 91 days. A 1 m-long dropping nitrification unit was fed with synthetic groundwater containing 30 mg-NH4+-N/L at a flow rate of 2.16 L/d. The outlet of the dropping nitrification unit was connected to the cotton-based denitrification unit. The NH4+ present in the groundwater was completely oxidized (>90% nitrification efficiency) by nitrifying bacteria to nitrite (NO2–) and nitrate (NO3–) in the dropping nitrification unit. Subsequently, the generated NO2– and NO3– were denitrified (96%–98% denitrification efficiency) by denitrifying bacteria in the cotton-based denitrification unit under anoxic conditions. Organic carbons released from the cotton presumably acted as electron donors for heterotrophic denitrification. Nitrifying and denitrifying bacteria were colonized in higher abundance in the dropping nitrification and cotton-based denitrification units, respectively. The total N removal rate and efficiency of the dropping nitrification–cotton-based denitrification reactor for 91 days were 58.1–66.9 mg-N/d and 96%–98%, respectively. Therefore, the dropping nitrification–cotton-based denitrification reactor will be an efficient, sustainable, and promising option for total N removal from NH4+-contaminated groundwater.

Does influent COD/N ratio affect nitrogen removal and N2O emission in a novel biochar-sludge amended soil wastewater infiltration system (SWIS)?

2018 ◽  
Vol 78 (2) ◽  
pp. 347-357 ◽  
Author(s):  
Fanping Zheng ◽  
Chaoquan Tan ◽  
Wanyuan Hou ◽  
Linli Huang ◽  
Jing Pan ◽  
...  
Keyword(s):  
Nitrogen Removal ◽  
Emission Rate ◽  
N2o Emission ◽  
Nitrifying Bacteria ◽  
N2o Emissions ◽  
Intermittent Aeration ◽  
Ratio Increase ◽  
Removal Rates ◽  
N Removal ◽  
Amended Soil

Abstract Nitrogen removal and N2O emission of a biochar-sludge amended soil wastewater infiltration system (SWIS) with/without intermittent aeration under different influent COD/N ratios was investigated. Nitrogen removal and N2O emission were affected by influent COD/N ratio. Under a COD/N ratio between 1:1 and 15:1, average chemical oxygen demand (COD), NH4+-N and total nitrogen (TN) removal rates decreased with COD/N ratio increase in non-aerated SWISs amended with/without biochar-sludge; an increasing COD/N ratio hardly affected COD and NH4+-N removal in a biochar-sludge amended SWIS with intermittent aeration; the N2O emission rate decreased with COD/N ratio increase in the studied SWISs. The biochar-sludge amended SWIS with intermittent aeration achieved high COD (92.2%), NH4+-N (96.8%), and TN (92.7%) removal rates and a low N2O emission rate (10.6 mg/(m2 d)) under a COD/N ratio of 15:1, which was higher than those in non-aerated SWISs amended with/without biochar-sludge. Combining the biochar-sludge amended SWIS with intermittent aeration enhanced the number of nitrifying bacteria, denitrifying bacteria, nitrate reductase activities, nitrite reductase activities, and improved the abundance of nitrogen removal functional genes under a high influent COD/N ratio. The results suggested that the joint use of intermittent aeration and biochar-sludge in a SWIS could be an effective and appropriate strategy for improving nitrogen removal and reducing N2O emissions in treating high COD/N ratio wastewater.

Kinetic study on nitrification of ammonium nitrogen-enriched synthetic wastewater using activated sludge

2020 ◽  
Vol 81 (1) ◽  
pp. 62-70
Author(s):  
Roumi Bhattacharya ◽  
Debabrata Mazumder
Keyword(s):  
Activated Sludge ◽  
Nitrogen Removal ◽  
Suspended Solids ◽  
Removal Rate ◽  
Nitrogen Concentration ◽  
Ammonium Nitrogen ◽  
Synthetic Wastewater ◽  
Yield Coefficient ◽  
Ammonium Oxidation ◽  
Consecutive Reaction

Abstract Nitrification of ammonium nitrogen (NH4+-N)-bearing synthetic wastewater was performed in a batch-activated sludge reactor by varying the initial ammonium nitrogen concentration up to 400 mg/L at a pH of 8.1 ± 0.2 and temperature of 36 ± 2 °C for developing the process kinetics using acclimatised biomass. Maximum ammonium nitrogen removal efficiency of 98.3% was achieved with initial ammonium nitrogen and mixed liquor suspended solids concentration of 235 mg/L and 2,180 mg/L, respectively, at 48 h batch period. Based on the experimental results, kinetic constants for ammonia nitrogen removal following Monod's approach were obtained as maximum substrate removal rate coefficient = 0.057 per day, yield coefficient = 0.336 mg volatile suspended solids/mg ammonium nitrogen, half velocity constant = 12.95 mg NH4+-N/L and endogenous decay constant = 0.02 per day. Nitrification is a consecutive reaction with ammonium oxidation as the first step followed by nitrite oxidation. The overall rate of nitrite and nitrate formation was observed to be 1.44 per day and 0.34 per day, respectively.

454 pyrosequencing-based characterization of the bacterial consortia in a well established nitrifying reactor

2015 ◽  
Vol 72 (6) ◽  
pp. 990-997 ◽  
Author(s):  
Rocio Ramirez-Vargas ◽  
Nancy Serrano-Silva ◽  
Yendi E. Navarro-Noya ◽  
Rocio J. Alcántara-Hernández ◽  
Marco Luna-Guido ◽  
...  
Keyword(s):  
Extracellular Polymeric Substances ◽  
High Throughput Sequencing ◽  
Removal Rate ◽  
Nitrifying Bacteria ◽  
Organic Load ◽  
Continuous Stirred Tank Reactor ◽  
Bacterial Consortia ◽  
Continuous Stirred Tank ◽  
Planktonic Community

This present study aimed to characterize the bacterial community in a well-established nitrifying reactor by high-throughput sequencing of 16S rRNA amplicons. The laboratory-scale continuous stirred tank reactor has been supplied with ammonium (NH4+) as sole energy source for over 5 years, while no organic carbon has been added, assembling thus a unique planktonic community with a mean NH4+ removal rate of 86 ± 1.4 mg NH4+-N/(L d). Results showed a nitrifying community composed of bacteria belonging to Nitrosomonas (relative abundance 11.0%) as the sole ammonia oxidizers (AOB) and Nitrobacter (9.3%) as the sole nitrite oxidizers (NOB). The Alphaproteobacteria (42.3% including Nitrobacter) were the most abundant class within the Proteobacteria (62.8%) followed by the Gammaproteobacteria (9.4%). However, the Betaproteobacteria (excluding AOB) contributed only 0.08%, confirming that Alpha- and Gammaproteobacteria thrived in low-organic-load environments while heterotrophic Betaproteobacteria are not well adapted to these conditions. Bacteroidetes, known to metabolize extracellular polymeric substances produced by nitrifying bacteria and secondary metabolites of the decayed biomass, was the second most abundant phylum (30.8%). It was found that Nitrosomonas and Nitrobacter sustained a broad population of heterotrophs in the reactor dominated by Alpha- and Gammaproteobacteria and Bacteroidetes, in a 1:4 ratio of total nitrifiers to all heterotrophs.

Impact of Partial Backwashing to Ammonia Nitrogen Removal in Biological Aerated Filter

2011 ◽  
Vol 183-185 ◽  
pp. 720-724 ◽  
Author(s):  
Ping Li ◽  
Li Long Yan ◽  
Fang Ma
Keyword(s):  
Low Temperature ◽  
Protective Effect ◽  
Nitrogen Removal ◽  
Removal Rate ◽  
Ammonia Nitrogen ◽  
Ammonia Removal ◽  
Nitrifying Bacteria ◽  
Biological Aerated Filter ◽  
Previous Level ◽  
Aerated Filter

Biological Aerated Filter has the drawback of severe plug under low temperature, and frequent back-washing would cause the bad performance of ammonia removal. To solve these shortcomings, partial backwashing experiment was carried out to test its amelioration effect on Biological Aerated Filter. The result showed that performing backwashing at the 40 cm of filter had strong protective effect on nitrifying bacteria, the ammonia removal could be improved gradually with the highest removal rate of 71.71%. Partial backwashing affected less on ammonia removal and the removal efficiency could be restored to the previous level after the backwashing completed for 2.5 h.

Effect of internal recycle rate on the high-strength nitrogen wastewater treatment in the combined UBF/MBR system

2005 ◽  
Vol 51 (10) ◽  
pp. 241-247 ◽  
Author(s):  
Y.T. Ahn ◽  
S.T. Kang ◽  
S.R. Chae ◽  
J.L. Lim ◽  
S.H. Lee ◽  
...  
Keyword(s):  
Surface Charge ◽  
Removal Efficiency ◽  
Nitrogen Removal ◽  
Membrane Fouling ◽  
Extracellular Polymeric Substances ◽  
Synthetic Wastewater ◽  
High Concentration ◽  
Combined System ◽  
Recycle Rate ◽  
Influent Flow

An anaerobic/aerobic system combining an anaerobic upflow-sludge bed filter (UBF) and an aerobic membrane bioreactor (MBR) was operated to enhance organic and nitrogen removal efficiency. The internal recycle rate, which is one of the most important operation factors that affects overall removal efficiency, was varied from 100% to 300% of the influent flow. Under these conditions, the overall removal efficiencies of organic and nitrogen and characteristics of membrane fouling in the combined system treating the synthetic wastewater including high concentration of organics and nutrients were studied. As a result, nitrogen removal efficiency was increased to 67% when the internal recycle rate was 300% of influent flow rate. As the internal recycle ratio increased from 100% to 200%, protein content decreased by 17% and carbohydrate content increased by 12%. However, there was no remarkable difference in total extracellular polymeric substances (EPS) content. At the high recycle rate of 300%, the surface charge of sludge was decreased while hydrophobicity (specific ultraviolet absorbance, SUVA) was increased. The differences in SUVA and surface charge were 11% and 1%, respectively. It is concluded that SUVA and EPS composition were important parameters affecting membrane fouling in the combined system.

Research of Carbon and Nitrogen Ratio and Sludge Stability in Aerobic Granular Sludge Bioreactor

2012 ◽  
Vol 518-523 ◽  
pp. 473-477
Author(s):  
Xia Zhao ◽  
Hui Xia Feng ◽  
Feng Jiang ◽  
Na Li Chen ◽  
Xiao Chun Wang
Keyword(s):  
Removal Efficiency ◽  
Nitrogen Removal ◽  
Removal Rate ◽  
Batch Reactor ◽  
Granular Sludge ◽  
Ammonia Nitrogen ◽  
Nitrifying Bacteria ◽  
Aerobic Granular Sludge ◽  
Nitrogen Ratio ◽  
The Stability

In sequencing batch reactor aerobic granular sludge was cultivated, and the influence of influent C/N ratio to aerobic granular sludge was studied. The results showed that the granulation and the settling ability of the sludge were poor in high C/N, however, low C/N was beneficial to the accumulation of microorganism in reactor and MLSS could reach to as high as 8740 mg/L. Lower C/N ratio would lead to increase of particle size and disintegrate of loose structure and overgrowth on filamentous microbe, these were disadvantage of the stability of the system. It was not obvious that influent C/N ratio affected on the organic removal. The COD removal maintained at 87% after the preliminary form particles were formed in reactor. When C/N ratio was 100:15~100:35, the phosphorus removal efficiency was good. If C/N ratio was too high or too low, the formation of sludge granulation would be affected in the process. The influence of C/N ratio to ammonia nitrogen removal efficiency was obvious. While C/N ratio was 100:10, granular sludge had good simultaneous nitrification and denitrification performance, and the average removal of ammonia nitrogen attained to 91%. But low C/N ratio was able to inhibit the activity of nitrifying bacteria and denitrifying bacteria. At that time, ammonia nitrogen removal rate declined sharply in the system.

Organic Stabilization and Nitrogen Removal in Membrane Separation Bioreactor for Domestic Wastewater Treatment

1992 ◽  
Vol 25 (10) ◽  
pp. 231-240 ◽  
Author(s):  
C. Chiemchaisri ◽  
Y. K. Wong ◽  
T. Urase ◽  
K. Yamamoto
Keyword(s):  
Total Nitrogen ◽  
Nitrogen Removal ◽  
Hollow Fiber ◽  
Membrane Separation ◽  
Hollow Fiber Membrane ◽  
Membrane Surface ◽  
Aeration Tank ◽  
Intermittent Aeration ◽  
Permeate Flux ◽  
Fiber Membrane

In this study, organic stabilization and nitrogen removal were investigated using a household type hollow fiber membrane separation bioreactor of 6 2 1 volume. The process employed direct solid-liquid separation by hollow fiber membrane inside an activated sludge aeration tank. By providing highly turbulent conditions within the separation zone in conjunction with Jet aerating installation inside the membrane module, sludge accumulation on the membrane surface and inside the module can be reduced. Permeate flux obtained after 330 days of operation was 0.2 m/d under intermittent suction. High degree of organic stabilization was obtained in the system by operation without sludge wastage except for sampling purposes. Continuous and intermittent aeration modes were investigated in the study. The average effluent COD concentration of 20.8 and 16.5 mg/l were observed during continuous and intermittent aerating application respectively. Degree of nitrification depended upon DO concentration of mixed liquor during aeration period. Introduction of intermittent aeration enhanced total nitrogen removal up to 80% or more by simultaneous nitrification and denitrification, resulting in average of 4.9 mg/l of total nitrogen in the effluent. Increase in DO in aeration period from 1.5–2 mg/l to 4–5 mg/l improved percentage of nitrogen removal to more than 90%. Rejection of 4–6 log virus concentration by gel layer formed on the membrane surface was also observed.

High-rate nitrification of electronic industry wastewater by using nitrifying granules

2017 ◽  
Vol 76 (11) ◽  
pp. 3171-3180 ◽  
Author(s):  
Yoshiaki Hasebe ◽  
Hiroaki Meguro ◽  
Yuuki Kanai ◽  
Masahiro Eguchi ◽  
Toshifumi Osaka ◽  
...  
Keyword(s):  
Removal Rate ◽  
Pilot Scale ◽  
Ammonia Removal ◽  
High Rate ◽  
Synthetic Wastewater ◽  
Nitrifying Bacteria ◽  
Test Plant ◽  
Ammonia Oxidizing Bacteria ◽  
Water Conduction ◽  
Industry Wastewater

Abstract Nitrifying granules have a high sedimentation property and an ability to maintain a large amount of nitrifying bacteria in a reaction tank. Our group has examined the formation process of nitrifying granules and achieved high-rate nitrification for an inorganic synthetic wastewater using these granules. In this research, a pilot-scale test plant with an 850-liter reaction tank was assembled in a semiconductor manufacturing factory in order to conduct a continuous water conduction test using real electronics industry wastewater. The aim was to observe the formation of nitrifying granules and determine the maximum ammonia removal rate. The average granule diameter formed during the experiment was 780 μm and the maximum ammonia removal rate was observed to be 1.5 kgN·m−3·day−1 at 20 °C, which is 2.5–5 times faster than traditional activated sludge methods. A fluorescence in situ hybridization analysis showed that β-proteobacterial ammonia oxidizing bacteria and the Nitrospira-like nitrite-oxidizing bacteria dominate the bacteria population in the granules, and their strong aggregation capacity might confer some benefits to the formation of these nitrifying granules.

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