scholarly journals Apparent oxygen half saturation constant for nitrifiers: genus specific, inherent physiological property, or artefact of colony morphology?

2018 ◽  
Author(s):  
Yingyu Law ◽  
Artur Matysik ◽  
Xueming Chen ◽  
Sara Swa Thi ◽  
Thi Quynh Ngoc Nguyen ◽  
...  
Keyword(s):  
Wastewater Treatment Plants ◽  
Volume Ratio ◽  
Domestic Wastewater ◽  
Physiological Property ◽  
Full Scale ◽  
Ammonia Oxidizing Bacteria ◽  
Low Oxygen ◽  
Half Saturation Constant ◽  
Nitrite Oxidizing Bacteria ◽  
Oxygenation Level

AbstractWe report that a singleNitrospirasublineage I OTU performs nitrite oxidation in several full-scale domestic wastewater treatment plants (WWTPs) in the tropics (29-31 °C). Contrary to the prevailing theory for the relationship between nitrite oxidizing bacteria (NOB) and ammonia oxidizing bacteria (AOB), members of theNitrospirasublineage I OTU had an apparent half saturation coefficient,Ks(app)lower than that of the full-scale domestic activated sludge cohabitant AOB (0.09 ± 0.02 g O2 m−3versus 0.3 ± 0.03 g O2 m−3). Paradoxically, NOB may thus thrive under conditions of low oxygen supply. Low dissolved oxygen (DO) conditions could enrich for and high aeration inhibit the NOB in a long-term lab-scale reactor. The relative abundance ofNitrospiragradually decreased with increasing DO until it was washed out. Nitritation was sustained even after the DO was lowered subsequently. Based on 3D-fluorescencein situhybridization (FISH) image analysis, the morphologies of AOB and NOB microcolonies responded to DO levels in accordance with their apparent oxygen half saturation constantKs(app). When exposed to the same oxygenation level, NOB formed densely packed spherical clusters with a low surface area-to-volume ratio compared to theNitrosomonas-like AOB clusters, which maintained a porous and non-spherical morphology. Microcolony morphology is thus a way for AOB and NOB to regulate oxygen exposure and sustain the mutualistic interaction. However, short-term high DO exposure can select for AOB and against NOB in full-scale domestic WWTPs and such population dynamics depend on which specific AOB and NOB species predominate under given environmental conditions.

Molecular assessment of ammonia- and nitrite-oxidizing bacteria in full-scale activated sludge wastewater treatment plants

2003 ◽  
Vol 48 (8) ◽  
pp. 119-126 ◽  
Author(s):  
K.G. Robinson ◽  
H.M. Dionisi ◽  
G. Harms ◽  
A.C. Layton ◽  
I.R. Gregory ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
16S Rdna ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Amoa Gene ◽  
Full Scale ◽  
Ammonia Oxidizing Bacteria ◽  
Copy Numbers ◽  
Nitrite Oxidizing Bacteria

Nitrification was assessed in two full-scale wastewater treatment plants (WWTPs) over time using molecular methods. Both WWTPs employed a complete-mix suspended growth, aerobic activated sludge process (with biomass recycle) for combined carbon and nitrogen treatment. However, one facility treated primarily municipal wastewater while the other only industrial wastewater. Real time PCR assays were developed to determine copy numbers for total 16S rDNA (a measure of biomass content), the amoA gene (a measure of ammonia-oxidizers), and the Nitrospira 16S rDNA gene (a measure of nitrite-oxidizers) in mixed liquor samples. In both the municipal and industrial WWTP samples, total 16S rDNA values were approximately 2-9 × 1013 copies/L and Nitrospira 16S rDNA values were 2-4 × 1010 copies/L. amoA gene concentrations averaged 1.73 × 109 copies/L (municipal) and 1.06 × 1010 copies/L (industrial), however, assays for two distinct ammonia oxidizing bacteria were required.

Predicting N2O emissions from nitrifying and denitrifying biofilms: a modeling study

2016 ◽  
Vol 75 (3) ◽  
pp. 530-538 ◽  
Author(s):  
Fabrizio Sabba ◽  
Cristian Picioreanu ◽  
Joshua P. Boltz ◽  
Robert Nerenberg
Keyword(s):  
Wastewater Treatment Plants ◽  
Oxygen Demand ◽  
N2o Emissions ◽  
Ammonia Oxidizing Bacteria ◽  
Biofilm Thickness ◽  
Biofilm Model ◽  
Suspended Growth ◽  
Nitrite Oxidizing Bacteria ◽  
The Difference ◽  
And Diffusion

Wastewater treatment plants can be significant sources of nitrous oxide (N2O), a potent greenhouse gas. While our understanding of N2O emissions from suspended-growth processes has advanced significantly, less is known about emissions from biofilm processes. Biofilms may behave differently due to their substrate gradients and microbial stratification. In this study, we used mathematical modeling to explore the mechanisms of N2O emissions from nitrifying and denitrifying biofilms. Our ammonia-oxidizing bacteria biofilm model suggests that N2O emissions from biofilm can be significantly greater than from suspended-growth systems. The driving factor is the diffusion of hydroxylamine, a nitrification intermediate, from the aerobic to the anoxic regions of the biofilm. The presence of nitrite-oxidizing bacteria further increased emissions. For denitrifying biofilms, our results suggest that emissions are generally greater than for suspended-growth systems. However, the magnitude of the difference depends on the bulk dissolved oxygen, chemical oxygen demand, and nitrate concentrations, as well as the biofilm thickness. Overall, the accumulation and diffusion of key intermediates, i.e. hydroxylamine and nitrite, distinguish biofilms from suspended-growth systems. Our research suggests that the mechanisms of N2O emissions from biofilms are much more complex than suspended-growth systems, and that emissions may be higher in many cases.

scholarly journals Pharmaceuticals and personal care products’ (PPCPs) impact on enriched nitrifying cultures

2021 ◽  
Author(s):  
Carla Lopez ◽  
Mac-Anthony Nnorom ◽  
Yiu Fai Tsang ◽  
Charles W. Knapp
Keyword(s):  
Wastewater Treatment Plants ◽  
Personal Care Products ◽  
Inhibitory Effect ◽  
Mitigation Measures ◽  
Nitrifying Bacteria ◽  
Ammonia Oxidizing Bacteria ◽  
Personal Care ◽  
Nitrite Oxidizing Bacteria ◽  
Inhibition Of Nitrification ◽  
The Impact

AbstractThe impact of pharmaceutical and personal care products (PPCPs) on the performance of biological wastewater treatment plants (WWTPs) has been widely studied using whole-community approaches. These contaminants affect the capacity of microbial communities to transform nutrients; however, most have neither honed their examination on the nitrifying communities directly nor considered the impact on individual populations. In this study, six PPCPs commonly found in WWTPs, including a stimulant (caffeine), an antimicrobial agent (triclosan), an insect repellent ingredient (N,N-diethyl-m-toluamide (DEET)) and antibiotics (ampicillin, colistin and ofloxacin), were selected to assess their short-term toxic effect on enriched nitrifying cultures: Nitrosomonas sp. and Nitrobacter sp. The results showed that triclosan exhibited the greatest inhibition on nitrification with EC50 of 89.1 μg L−1. From the selected antibiotics, colistin significantly affected the overall nitrification with the lowest EC50 of 1 mg L−1, and a more pronounced inhibitory effect on ammonia-oxidizing bacteria (AOB) compared to nitrite-oxidizing bacteria (NOB). The EC50 of ampicillin and ofloxacin was 23.7 and 12.7 mg L−1, respectively. Additionally, experimental data suggested that nitrifying bacteria were insensitive to the presence of caffeine. In the case of DEET, moderate inhibition of nitrification (<40%) was observed at 10 mg L−1. These findings contribute to the understanding of the response of nitrifying communities in presence of PPCPs, which play an essential role in biological nitrification in WWTPs. Knowing specific community responses helps develop mitigation measures to improve system resilience.

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).

Full-scale experience with the deammonification process to treat high strength sludge water – a case study

2012 ◽  
Vol 65 (3) ◽  
pp. 447-455 ◽  
Author(s):  
N. Jardin ◽  
J. Hennerkes
Keyword(s):  
Wastewater Treatment Plants ◽  
High Strength ◽  
Full Scale ◽  
Lag Phase ◽  
Stable Operation ◽  
Low Oxygen ◽  
Recent Developments ◽  
Treatment Train ◽  
Volumetric Loading ◽  
Nitrogen Elimination

More stringent effluent criteria with regard to nitrogen calls for improved nutrient removal techniques in wastewater treatment plants (WWTPs). Besides optimisation of the liquid treatment train of the plants, attention has increasingly centred on the problem of return flows from sludge treatment. One of the most recent developments aimed at the reduction of this nitrogen load is deammonification which has been used at one of Ruhrverband's plants since 2002 by applying a moving bed system. To gain additional experience in operating this process, another full scale plant was modified in 2007 by integration of deammonification, using a SBR system with suspended biomass based on the DEMON® control scheme. By using seeding sludge from Strass WWTP in Austria, start-up has been achieved within only 1 day. After stable operation for several months, increasing nitrate concentrations were observed in the effluent of the system indicating growing activity of nitrite oxidising bacteria (NOB). Following severe process deterioration, it was decided to re-start the system again but the same behaviour, i.e. increasing levels of nitrate, was observed once again. Several approaches were used to suppress NOB organisms in full-scale without success, e.g. low oxygen levels and high free ammonia concentrations. Finally, the reduction of the aerobic cycle length during intermittent aeration down to 8 min, followed by an anoxic mixing period of only 18 min was successful in inhibiting the activity of NOB organisms, most probably due to their elevated lag-phase compared with ammonium oxidising bacteria. Today, nitrogen elimination that has been stabilised at more than 80% at a daily volumetric loading rate of 0.5 kg N/(m3 d). The total costs amount to €2.3/kg Neli.

scholarly journals Metagenomic Evidence for the Presence of Comammox Nitrospira-Like Bacteria in a Drinking Water System

mSphere ◽  
2015 ◽  
Vol 1 (1) ◽  
Author(s):  
Ameet J. Pinto ◽  
Daniel N. Marcus ◽  
Umer Zeeshan Ijaz ◽  
Quyen Melina Bautista-de lose Santos ◽  
Gregory J. Dick ◽  
...  
Keyword(s):  
Drinking Water ◽  
Wastewater Treatment Plants ◽  
Inorganic Nitrogen ◽  
Water System ◽  
Ammonia Oxidizing Bacteria ◽  
Water And Wastewater Treatment ◽  
Single Organism ◽  
Nitrite Oxidizing Bacteria ◽  
Aerobic Nitrification ◽  
Engineered Systems

ABSTRACT Nitrification plays an important role in regulating the concentrations of inorganic nitrogen species in a range of environments, from drinking water and wastewater treatment plants to the oceans. Until recently, aerobic nitrification was considered to be a two-step process involving ammonia-oxidizing bacteria or archaea and nitrite-oxidizing bacteria. This process requires close cooperation between these two functional guilds for complete conversion of ammonia to nitrate, without the accumulation of nitrite or other intermediates, such as nitrous oxide, a potent greenhouse gas. The discovery of a single organism with the potential to oxidize both ammonia and nitrite adds a new dimension to the current understanding of aerobic nitrification, while presenting opportunities to rethink nitrogen management in engineered systems. We report metagenomic evidence for the presence of a Nitrospira-like organism with the metabolic potential to perform the complete oxidation of ammonia to nitrate (i.e., it is a complete ammonia oxidizer [comammox]) in a drinking water system. This metagenome bin was discovered through shotgun DNA sequencing of samples from biologically active filters at the drinking water treatment plant in Ann Arbor, MI. Ribosomal proteins, 16S rRNA, and nxrA gene analyses confirmed that this genome is related to Nitrospira-like nitrite-oxidizing bacteria. The presence of the full suite of ammonia oxidation genes, including ammonia monooxygenase and hydroxylamine dehydrogenase, on a single ungapped scaffold within this metagenome bin suggests the presence of recently discovered comammox potential. Evaluations based on coverage and k-mer frequency distribution, use of two different genome-binning approaches, and nucleic acid and protein similarity analyses support the presence of this scaffold within the Nitrospira metagenome bin. The amoA gene found in this metagenome bin is divergent from those of canonical ammonia and methane oxidizers and clusters closely with the unusual amoA gene of comammox Nitrospira. This finding suggests that previously reported imbalances in abundances of nitrite- and ammonia-oxidizing bacteria/archaea may likely be explained by the capacity of Nitrospira-like organisms to completely oxidize ammonia. This finding might have significant implications for our understanding of microbially mediated nitrogen transformations in engineered and natural systems. IMPORTANCE Nitrification plays an important role in regulating the concentrations of inorganic nitrogen species in a range of environments, from drinking water and wastewater treatment plants to the oceans. Until recently, aerobic nitrification was considered to be a two-step process involving ammonia-oxidizing bacteria or archaea and nitrite-oxidizing bacteria. This process requires close cooperation between these two functional guilds for complete conversion of ammonia to nitrate, without the accumulation of nitrite or other intermediates, such as nitrous oxide, a potent greenhouse gas. The discovery of a single organism with the potential to oxidize both ammonia and nitrite adds a new dimension to the current understanding of aerobic nitrification, while presenting opportunities to rethink nitrogen management in engineered systems.

scholarly journals Pharmaceuticals and Personal Care Products (PPCPs) Impact Enriched Nitrifying Cultures

2021 ◽  
Author(s):  
Carla Lopez ◽  
Mac-Anthony Nnorom ◽  
Yiu Fai Tsang ◽  
Charles W Knapp
Keyword(s):  
Wastewater Treatment Plants ◽  
Personal Care Products ◽  
Inhibitory Effect ◽  
Mitigation Measures ◽  
Nitrifying Bacteria ◽  
Ammonia Oxidizing Bacteria ◽  
Personal Care ◽  
Nitrite Oxidizing Bacteria ◽  
Inhibition Of Nitrification ◽  
The Impact

Abstract The impact of pharmaceutical and personal care products (PPCPs) on the performance of biological wastewater treatment plants (WWTPs) has been widely studied using whole-community approaches. These contaminants affect the capacity of microbial communities to transform nutrients; however, most have neither honed their examination on the nitrifying communities directly nor considered the impact on individual populations. In this study, six PPCPs commonly found in WWTPs, including a stimulant (caffeine), an antimicrobial agent (triclosan), an insect repellent ingredient (N,N-diethyl-m-toluamide (DEET)), and antibiotics (ampicillin, colistin, and ofloxacin), were selected to assess their short-term toxic effect on enriched nitrifying cultures: Nitrosomonas sp. and Nitrobacter sp. The results showed that triclosan exhibited the greatest inhibition on nitrification with EC50 of 89.1 µg L− 1. From the selected antibiotics, colistin significantly affected the overall nitrification with the lowest EC50 of 1 mg L− 1, and a more pronounced inhibitory effect on ammonia-oxidizing bacteria (AOB) compared to nitrite-oxidizing bacteria (NOB). The EC50 of ampicillin and ofloxacin were 22 and 12.7 mg L− 1, respectively. Additionally, experimental data suggested that nitrifying bacteria were insensitive to the presence of caffeine. In the case of DEET, moderate inhibition of nitrification (< 40%) was observed at the highest concentration tested. These findings contribute to the understanding of the response of nitrifying communities in presence of PPCPs, which play an essential role in biological nitrification in WWTPs. Knowing specific community responses helps develop mitigation measures to improve system resilience.

scholarly journals Combined impact of TiO2 nanoparticles and antibiotics on the activity and bacterial community of partial nitrification system

PLoS ONE ◽  
2021 ◽  
Vol 16 (11) ◽  
pp. e0259671
Author(s):  
Han Xu ◽  
Binghua Liu ◽  
Wenyu Qi ◽  
Meng Xu ◽  
Xiaoyu Cui ◽  
...  
Keyword(s):  
Wastewater Treatment Plants ◽  
Cell Permeability ◽  
Partial Nitrification ◽  
Batch Reactors ◽  
Ammonia Oxidizing Bacteria ◽  
Sequencing Batch Reactors ◽  
Flow Cytometry Analysis ◽  
Batch Experiments ◽  
Nitrite Oxidizing Bacteria ◽  
Combined Impact

The effects of TiO2 nanoparticles (nano-TiO2) together with antibiotics leaking into wastewater treatment plants (WWTPs), especially the partial nitrification (PN) process remain unclear. To evaluate the combined impact and mechanisms of nano-TiO2 and antibiotics on PN systems, batch experiments were carried out with six bench-scale sequencing batch reactors. Nano-TiO2 at a low level had minimal effects on the PN system. In combination with tetracycline and erythromycin, the acute impact of antibiotics was enhanced. Both steps of nitrification were retarded due to the decrease of bacterial activity and abundance, while nitrite-oxidizing bacteria were more sensitive to the inhibition than ammonia-oxidizing bacteria. Proteobacteria at the phylum level and Nitrosospira at the genus level remained predominant under single and combined impacts. The flow cytometry analysis showed that nano-TiO2 enhanced the toxicity of antibiotics through increasing cell permeability. Our results can help clarify the risks of nano-TiO2 combined with antibiotics to PN systems and explaining the behavior of nanoparticles in WWTPs.

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