scholarly journals Impact of Protozoan Grazing on Nitrification and the Ammonia-And-Nitrite-Oxidizing Bacterial Communities in Activated Sludge

2021 ◽  
Author(s):  
Amy Jean Pogue
Keyword(s):  
Activated Sludge ◽  
Ammonia Oxidation ◽  
Heterotrophic Bacteria ◽  
Grazing Pressure ◽  
Batch Reactors ◽  
Protozoan Grazing ◽  
Nitrite Oxidizing Bacteria ◽  
Nitrogen Concentrations ◽  
Nitrite Nitrate

The effect of protozoan grazing on nitrification rates under different conditions was examined. The spatial distribution of ammonia -and nitrite- oxidizing bacteria (AOB and NOB) in activated sludge was also examined using FISH/CSLM. Batch reactors were monitored for ammonia, nitrite, nitrate, and total nitrogen concentrations and bacterial numbers in the presence and absence of cycloheximide, a protozoan inhibitor. In the absence of protozoan grazing, rates of nitrification were lower than in batches with protozoa. Spatially, both AOB and NOB were found clustered within the floc and neither inhibiting the protozoa or inhibiting ammonia oxidation appeared to lower the amount of AOB and NOB present or their position. These results suggest that a reduction in protozoan grazing pressure allowed the heterotrophic bacteria to proliferate which caused a corresponding decrease in the rate of nitrification. These results suggest that AOB and NOB are less active in the absence of protozoa and indicates the role of protozoa in the cycling of nitrogen.

scholarly journals Impact of Protozoan Grazing on Nitrification and the Ammonia-And-Nitrite-Oxidizing Bacterial Communities in Activated Sludge

2021 ◽  
Author(s):  
Amy Jean Pogue
Keyword(s):  
Activated Sludge ◽  
Ammonia Oxidation ◽  
Heterotrophic Bacteria ◽  
Grazing Pressure ◽  
Batch Reactors ◽  
Protozoan Grazing ◽  
Nitrite Oxidizing Bacteria ◽  
Nitrogen Concentrations ◽  
Nitrite Nitrate

The effect of protozoan grazing on nitrification rates under different conditions was examined. The spatial distribution of ammonia -and nitrite- oxidizing bacteria (AOB and NOB) in activated sludge was also examined using FISH/CSLM. Batch reactors were monitored for ammonia, nitrite, nitrate, and total nitrogen concentrations and bacterial numbers in the presence and absence of cycloheximide, a protozoan inhibitor. In the absence of protozoan grazing, rates of nitrification were lower than in batches with protozoa. Spatially, both AOB and NOB were found clustered within the floc and neither inhibiting the protozoa or inhibiting ammonia oxidation appeared to lower the amount of AOB and NOB present or their position. These results suggest that a reduction in protozoan grazing pressure allowed the heterotrophic bacteria to proliferate which caused a corresponding decrease in the rate of nitrification. These results suggest that AOB and NOB are less active in the absence of protozoa and indicates the role of protozoa in the cycling of nitrogen.

Impact of protozoan grazing on nitrification and the ammonia- and nitrite-oxidizing bacterial communities in activated sludge

2007 ◽  
Vol 53 (5) ◽  
pp. 559-571 ◽  
Author(s):  
Amy J. Pogue ◽  
Kimberley A. Gilbride
Keyword(s):  
Activated Sludge ◽  
Laser Scanning ◽  
Ammonia Oxidation ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Batch Reactors ◽  
Ammonia Oxidizing Bacteria ◽  
Nitrate Accumulation ◽  
Protozoan Grazing ◽  
Nitrite Nitrate

In activated sludge, protozoa feed on free-swimming bacteria and suspended particles, inducing flocculation and increasing the turnover rate of nutrients. In this study, the effect of protozoan grazing on nitrification rates under various conditions in municipal activated sludge batch reactors was examined, as was the spatial distribution of ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) within the activated sludge. The reactors were monitored for ammonia, nitrite, nitrate, and total nitrogen concentrations, and bacterial numbers in the presence and absence of cycloheximide (a protozoan inhibitor), allylthiourea (an inhibitor of ammonia oxidation), and EDTA (a deflocculating agent). The accumulations of nitrate, nitrite, and ammonia were lower in batches without than with protozoa grazing. Inhibition of ammonia oxidation also decreased the amount of nitrite and nitrate accumulation. Inhibiting protozoan grazing along with ammonia oxidation further decreased the amounts of nitrite and nitrate accumulated. Induction of deflocculation led to high nitrate accumulation, indicating high levels of nitrification; this effect was lessened in the absence of protozoan grazing. Using fluorescent in situ hybridization and confocal laser scanning microscopy, AOB and NOB were found clustered within the floc, and inhibiting the protozoa, inhibiting ammonia oxidation, or inducing flocculation did not appear to lower the number of AOB and NOB present or affect their position within the floc. These results suggest that the AOB and NOB are present but less active in the absence of protozoa.

Nitrification in activated sludge batch reactors is linked to protozoan grazing of the bacterial population

2005 ◽  
Vol 51 (9) ◽  
pp. 791-799 ◽  
Author(s):  
Penny Petropoulos ◽  
Kimberley A Gilbride
Keyword(s):  
Activated Sludge ◽  
Bacterial Population ◽  
Grazing Pressure ◽  
Nitrification Rate ◽  
Batch Reactors ◽  
Ammonia Oxidizing Bacteria ◽  
Bacterial Concentration ◽  
Batch Cultures ◽  
Protozoan Grazing ◽  
Swimming Bacteria

Protozoa feed upon free-swimming bacteria and suspended particles inducing flocculation and increasing the turnover rate of nutrients in complex mixed communities. In this study, the effect of protozoan grazing on nitrification was examined in activated sludge in batch cultures maintained over a 14-day period. A reduction in the protozoan grazing pressure was accomplished by using either a dilution series or the protozoan inhibitor cycloheximide. As the dilutions increased, the nitrification rate showed a decline, suggesting that a reduction in protozoan or bacterial concentration may cause a decrease in nitrification potential. In the presence of cycloheximide, where the bacterial concentration was not altered, the rates of production of ammonia, nitrite, and nitrate all were significantly lower in the absence of active protozoans. These results suggest that a reduction in the number or activity of the protozoans reduces nitrification, possibly by limiting the availability of nutrients for slow-growing ammonia and nitrite oxidizers through excretion products. Furthermore, the ability of protozoans to groom the heterotrophic bacterial population in such systems may also play a role in reducing interspecies competition for nitrification substrates and thereby augment nitrification rates.Key words: nitrification, activated sludge, protozoan grazing, ammonia-oxidizing bacteria, cycloheximide.

scholarly journals Removal of Ammonia Nitrogen by Activated Sludge Process Using Simultaneous Nitrification Denitrification Method

2020 ◽  
Vol 202 ◽  
pp. 05006
Author(s):  
Junaidi ◽  
Sri Sumiyati ◽  
Ronauli Sitinjak
Keyword(s):  
Activated Sludge ◽  
Operating Time ◽  
Carbon Sources ◽  
Ammonia Nitrogen ◽  
Nitrogen Inputs ◽  
Nitrogen Concentrations ◽  
Nitrification And Denitrification ◽  
Nitrite Nitrate ◽  
Biological Nitrogen ◽  
Activated Sludge Processes

Nitrogen concentrations are often found in ammonia, nitrite, nitrate, and neutral nitrogen waters. This research has investigated the simultaneous removal of biological nitrogen nitrification and denitrification (SND) in a continuous flow system of activated sludge processes. This research was conducted by variations in carbon sources is namely glucose and methanol. Variations of C / N ratios of 5, 10, and 20 were also carried out. The main parameters were analyzed every day until the end of the research period. The main parameter analyzed is ammonia-nitrogen. Besides, additional parameters were also analyzed in the form of COD, nitrate-nitrogen, nitrite-nitrogen, pH, MLSS, SVI, and DO. The results of research indicate artificially excess nitrogen wastewater can be treated using SND and can produce sufficiently good effluent quality if the operations are running optimally. The highest ammonia-nitrogen removal efficiency of 100% shown by the variation of the carbon methanol source and value of the C / N 20 ratio then followed by the C / N 10 ratio of 78% and the C / N 5 ratio of 59%. Overall, the data shown appropriate controls for carbon and nitrogen inputs are needed to achieve an efficient SND. Proper SND technology can save operating time and energy, and may replace two traditional stages: biological nitrification and denitrification processes.

scholarly journals Nitrification mainly driven by ammonia-oxidizing bacteria and nitrite-oxidizing bacteria in an anammox-inoculated wastewater treatment system

AMB Express ◽  
2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jing Lu ◽  
Yiguo Hong ◽  
Ying Wei ◽  
Ji-Dong Gu ◽  
Jiapeng Wu ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Nitrogen Removal ◽  
High Throughput Sequencing ◽  
High Efficiency ◽  
Ammonia Oxidation ◽  
Ammonia Oxidizing Bacteria ◽  
Ammonium Oxidation ◽  
Strong Activity ◽  
Nitrite Oxidizing Bacteria

AbstractAnaerobic ammonium oxidation (anammox) process has been acknowledged as an environmentally friendly and time-saving technique capable of achieving efficient nitrogen removal. However, the community of nitrification process in anammox-inoculated wastewater treatment plants (WWTPs) has not been elucidated. In this study, ammonia oxidation (AO) and nitrite oxidation (NO) rates were analyzed with the incubation of activated sludge from Xinfeng WWTPs (Taiwan, China), and the community composition of nitrification communities were investigated by high-throughput sequencing. Results showed that both AO and NO had strong activity in the activated sludge. The average rates of AO and NO in sample A were 6.51 µmol L−1 h−1 and 6.52 µmol L−1 h−1, respectively, while the rates in sample B were 14.48 µmol L−1 h−1 and 14.59 µmol L−1 h−1, respectively. The abundance of the nitrite-oxidizing bacteria (NOB) Nitrospira was 0.89–4.95 × 1011 copies/g in both samples A and B, the abundance of ammonia-oxidizing bacteria (AOB) was 1.01–9.74 × 109 copies/g. In contrast, the abundance of ammonia-oxidizing archaea (AOA) was much lower than AOB, only with 1.28–1.53 × 105 copies/g in samples A and B. The AOA community was dominated by Nitrosotenuis, Nitrosocosmicus, and Nitrososphaera, while the AOB community mainly consisted of Nitrosomonas and Nitrosococcus. The dominant species of Nitrospira were Candidatus Nitrospira defluvii, Candidatus Nitrospira Ecomare2 and Nitrospira inopinata. In summary, the strong nitrification activity was mainly catalyzed by AOB and Nitrospira, maintaining high efficiency in nitrogen removal in the anammox-inoculated WWTPs by providing the substrates required for denitrification and anammox processes.

Treatment of septage using single and two stage activated sludge batch reactors systems

1995 ◽  
Vol 32 (9-10) ◽  
pp. 95-104 ◽  
Author(s):  
A. D. Andreadakis ◽  
G. Kondili ◽  
D. Mamais ◽  
A. Noussi
Keyword(s):  
Activated Sludge ◽  
Nitrogen Removal ◽  
Removal Rate ◽  
Substantial Reduction ◽  
Subsequent Treatment ◽  
Batch Reactors ◽  
Two Stage ◽  
Second Stage ◽  
Nitrogen Concentrations ◽  
Stage System

The cyclic or sequencing batch activated sludge process was applied for the treatment of septage originating from cesspools serving non-sewered areas. Single and two stage systems were investigated in bench scale units. The single stage aerated system was capable in removing practically all the biodegradable COD and producing a well stabilised excess sludge with excellent settling and thickening characteristics. With respect to nitrogen the average removal rate was to the order of 70%, but the performance was unstable due to periodic strong inhibition of the nitrification process. Subsequent treatment in a second stage aerated unit improved nitrification but did not result in higher nitrogen removal rates due to the increased concentrations of oxidised nitrogen. An anoxic second stage post denitrification unit resulted in an overall nitrogen removal of 88%, through a substantial reduction of nitrates. Further improvement of the system, with nitrogen removal of about 95% and average effluent nitrogen concentrations lower than 10 mg.1−1, can be achieved by adoption of a two stage system consisting of a first aerated stage unit, followed by a second stage unit with alternating aerated and anoxic cycles and addition of external carbon during the anoxic cycle.

Effect of long-term idle periods on the performance of sequencing batch reactors

2000 ◽  
Vol 41 (1) ◽  
pp. 105-113 ◽  
Author(s):  
E. Morgenroth ◽  
A. Obermayer ◽  
E. Arnold ◽  
A. Brühl ◽  
M. Wagner ◽  
...  
Keyword(s):  
Ammonia Oxidation ◽  
Heterotrophic Bacteria ◽  
Batch Reactor ◽  
Effective Control ◽  
Nitrite Accumulation ◽  
Gene Probe ◽  
Minor Effect ◽  
Batch Reactors ◽  
A Minor

Sludge storage can be used as an effective control handle to adjust plant capacity to large influent variations. The sequencing batch reactor (SBR) technology is well suited for temporary sludge storage because reactors can easily be switched off individually and operated in an idle mode. In this study experimental results on the effect of long term (weeks) idle periods on nitrogen removal are presented. The SBRs were operated with idle times ranging from 6 to 20 days. Batch experiments were performed where sludge was stored without the addition of any substrate for 7 weeks. In the SBRs, repeated long-term idle phases had only a minor effect on ammonia oxidation. The nitrite oxidation process was more sensitive to long idle phases resulting in temporary nitrite accumulation in the SBRs. Quantitative gene probe analyses demonstrated that the decay of ammonia oxidizers was slower than the decay of nitrite oxidizers which in turn decayed slower than heterotrophic bacteria.

Start up of deammonification process in one single SBR system

2004 ◽  
Vol 50 (6) ◽  
pp. 1-8 ◽  
Author(s):  
X. Li ◽  
G. Zen ◽  
K.H. Rosenwinkel ◽  
S. Kunst ◽  
D. Weichgrebe ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Ammonia Oxidation ◽  
Molecular Nitrogen ◽  
Batch Reactors ◽  
Start Up ◽  
Anaerobic Ammonia Oxidation ◽  
Seed Sludge ◽  
Related Process ◽  
Nitrite Inhibition ◽  
Autotrophic Nitrogen Removal

A process for autotrophic nitrogen removal named aerobic/anoxic deammonification wherein NH4+ is oxidized by nearly 50% to NO2- and subsequently the ammonia is converted together with the nitrite to molecular nitrogen (N2 gas), has come to full-scale application within the last few years. In this research, sludge from a biological rotation disk located at a landfill leachate plant at Mechernich, Germany, which is capable of performing the deammonification process, was used as seed sludge for acclimating deammonification activities in laboratory scale batch-reactors. In parallel, the same tests were performed with normal activated sludge. Research results indicated that deammonification activities could be obtained from the seeded reactor and also, with limited performance, from normal activated sludge in a single SBR system after several months acclimation. It was also seen that oxygen is an important factor that influences the deammonification from both the acclimatization process and process running. Further results were approved that report an impact of nitrite as a process intermediate on the closely related process of anaerobic ammonia oxidation (“Anammox”). However, limiting concentrations on a bacteria population performing deammonification were found to be different to those reported for a pure Anammox-culture. Also the influence of another intermediate, hydrazine, was tested for speeding up the acclimating process by inducing the deammonification activities and recovering the activities of deammonification from nitrite inhibition.

Composition of extracellular polymeric substances in the activated sludge floc matrix

1998 ◽  
Vol 37 (4-5) ◽  
pp. 325-333 ◽  
Author(s):  
R. Bura ◽  
M. Cheung ◽  
B. Liao ◽  
J. Finlayson ◽  
B. C. Lee ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Surface Charge ◽  
Extracellular Polymeric Substances ◽  
Batch Reactors ◽  
Sequencing Batch Reactors ◽  
Microbial Flocs ◽  
Operation Conditions ◽  
Transmission Electron ◽  
Acidic Polysaccharides

The precise role of extracellular polymeric substances (EPS) in relation to the formation and physicochemical properties of microbial floc in wastewater treatment systems is not well known. Studies were undertaken to provide more comprehensive descriptions of EPS and properties of microbial floc. Acidic polysaccharides and DNA were relatively labile components of the EPS when biomass was stored at 4°C or at −20°C, and significant losses of these components were observed within 24 hours. The composition and properties of activated sludge were found to vary between different full-scale treatment systems reflecting the importance of wastewater composition and operation conditions on microbial communities and the response to environmental conditions. The COD:N:P ratio was found to influence hydrophobicity, surface charge and the EPS composition of microbial flocs in well-controlled bench-scale sequencing batch reactors. Phosphorus depleted and P-limited conditions resulted in a decrease in surface charge but increases in acidic polysaccharides which corresponded to a strong carboxyl stretch at 1740 cm−1 when the biomass was analysed by FTIR-spectroscopy. Electron dense particles, identified by energy-dispersive spectroscopy as containing iron, phosphorus and sulfur, were observed in the fibrils of the floc matrix by transmission electron microscopy.

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