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 Operational modifications for the development of nitrifying bacteria in a large-scale biological aerated filter and its impact on wastewater treatment

2018 ◽  
Vol 78 (8) ◽  
pp. 1704-1714 ◽  
Author(s):  
François-René Bourgeois ◽  
Frédéric Monette ◽  
Daniel G. Cyr
Keyword(s):  
Large Scale ◽  
Oxygen Demand ◽  
Bacterial Biofilm ◽  
Nitrifying Bacteria ◽  
Nitrification Rate ◽  
Total Biomass ◽  
Ammonia Oxidizing Bacteria ◽  
Operational Conditions ◽  
Nitrite Oxidizing Bacteria ◽  
Aerated Filter

Abstract To develop a better understanding for fixed biomass processes, the development of a nitrifying bacterial biofilm, as well as the performance of treatment during modifications to operational conditions of a full-scale submerged biological filter were examined. The development of the nitrifying biofilm was investigated at four depth levels (1, 2, 4 and 5 feet). The result of bacterial subpopulations analyzed by qPCR relative to the physico-chemical parameters of the wastewater during the various tests (sustained aeration, modified backwash parameters and inflow restriction) revealed an increase of the relative presence of nitrifying microorganisms throughout the biofilm (especially for nitrite oxidizing bacteria (NOB)), but this was not necessarily accompanied by a better nitrification rate. The highest observed nitrification rate was 49% of removal in the test cell during backwashing conditions, whereas the relative ammonia oxidizing bacteria (AOB) population was 0.032% and NOB was 0.008% of the total biomass collected. The highest percentage of nitrifying bacteria observed (0.034% AOB and 0.18% NOB) resulted in a nitrification rate of 21%. The treatment of organic matter determined by measuring the chemical and biochemical oxygen demand (COD, CBOD5) was improved.

scholarly journals Comparison Study of Manometric Respirometric Test and Common Chemical Methods in the Determination ofBOD7in a Pulp and Paper Mill's Wastewaters

2006 ◽  
Vol 2006 ◽  
pp. 1-5 ◽  
Author(s):  
Katri Roppola ◽  
Toivo Kuokkanen ◽  
Hannu Nurmesniemi ◽  
Jaakko Rämö ◽  
Risto Pöykiö ◽  
...  
Keyword(s):  
Wastewater Treatment Plants ◽  
Oxygen Demand ◽  
Paper Mill ◽  
Pulp And Paper ◽  
Comparison Study ◽  
Short Term ◽  
Chemical Methods ◽  
Paper Mills ◽  
The Difference

The biological oxygen demand (BOD) test is widely used in many wastewater treatment plants. The conventional BOD tests are usually time-consuming and the results are often out of date for process control purposes. The aim of this research was to compare the manometric respirometric test with common chemical methods in the determination of BOD of wastewater from a pulp and paper mills as well as to evaluate theBOD7values of both wastewaters from the short-term respirometric measurements. The results showed that there were differences in theBOD7values of paper mill samples measured by conventional and respirometric methods. The main cause was found to be the dilution solution used in the conventional BOD tests. Using the same mineral solution in the respirometric measurements diminished the difference remarkably. Evaluation of theBOD7value after two or three days incubation was proved to work very well and the estimated results were close to measured values (deviations 1%–12%).

Nitrous oxide production by lithotrophic ammonia-oxidizing bacteria and implications for engineered nitrogen-removal systems

2011 ◽  
Vol 39 (6) ◽  
pp. 1832-1837 ◽  
Author(s):  
Kartik Chandran ◽  
Lisa Y. Stein ◽  
Martin G. Klotz ◽  
Mark C.M. van Loosdrecht
Keyword(s):  
Nitrous Oxide ◽  
Nitrogen Removal ◽  
Ammonia Oxidation ◽  
Wastewater Treatment Plants ◽  
N2o Emissions ◽  
Ammonia Oxidizing Bacteria ◽  
N2o Production ◽  
Nitrogen Emissions ◽  
Greenhouse Gas Inventories ◽  
Nitrogen Concentrations

Chemolithoautotrophic AOB (ammonia-oxidizing bacteria) form a crucial component in microbial nitrogen cycling in both natural and engineered systems. Under specific conditions, including transitions from anoxic to oxic conditions and/or excessive ammonia loading, and the presence of high nitrite (NO2−) concentrations, these bacteria are also documented to produce nitric oxide (NO) and nitrous oxide (N2O) gases. Essentially, ammonia oxidation in the presence of non-limiting substrate concentrations (ammonia and O2) is associated with N2O production. An exceptional scenario that leads to such conditions is the periodical switch between anoxic and oxic conditions, which is rather common in engineered nitrogen-removal systems. In particular, the recovery from, rather than imposition of, anoxic conditions has been demonstrated to result in N2O production. However, applied engineering perspectives, so far, have largely ignored the contribution of nitrification to N2O emissions in greenhouse gas inventories from wastewater-treatment plants. Recent field-scale measurements have revealed that nitrification-related N2O emissions are generally far higher than emissions assigned to heterotrophic denitrification. In the present paper, the metabolic pathways, which could potentially contribute to NO and N2O production by AOB have been conceptually reconstructed under conditions especially relevant to engineered nitrogen-removal systems. Taken together, the reconstructed pathways, field- and laboratory-scale results suggest that engineering designs that achieve low effluent aqueous nitrogen concentrations also minimize gaseous nitrogen emissions.

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.

scholarly journals Model-based evaluation of the contribution of partial denitrification (PD) on the one-stage autotrophic nitrogen removal process

2021 ◽  
Author(s):  
Chi Zhang ◽  
Lianze Yu ◽  
Miao Zhang ◽  
Jun Wu
Keyword(s):  
Nitrogen Removal ◽  
Oxygen Demand ◽  
Anammox Bacteria ◽  
Removal Process ◽  
One Stage ◽  
Biofilm Model ◽  
Nitrite Oxidizing Bacteria ◽  
The One ◽  
Steady State Simulation ◽  
Autotrophic Nitrogen Removal

Abstract The nitrate produced by the one-stage partial nitritation-anammox (PN/A) process can be removed through partial denitrification (PD) by adding carbon source. In this study, a 1D multi-population biofilm model was developed to evaluate the contribution of partial denitrification on the one-stage autotrophic nitrogen removal process at influent NH4+ = 100 mg N/L. The dynamic simulation that was carried out to investigate the effect of nitrite-oxidizing bacteria (NOB) revealed that PD contributed to the reactor to obtain total nitrogen removal efficiency (TNR) of above 90% and the effluent nitrate was significantly decreased with the absence of NOB. However, PD decreased TNR of the one-stage PN/A process with the presence of NOB. Increased influent chemical oxygen demand (COD) widened the dissolved oxygen (DO) range required for high TNR whether NOB were present or not. The steady-state simulation results showed that NOB were always absent in the granules at high DO and COD levels and the optimum DO > 0.5 mg/L when influent COD was over 50 mg/L. Besides, higher influent COD/NH4+ (C/N) and larger granule diameter (diameter > 1600 µm) were contributed to widening the range of DO required for high TNR. The nitrogen removal contribution of anammox bacteria (AMX) was significantly higher than denitrification in the reactor.

Modelling the N2O Emissions in Municipal Wastewater Treatment Plants under Dynamic Conditions

10.29007/w6rq ◽  
2018 ◽  
Author(s):  
Theoni Massara ◽  
Borja Solis Duran ◽  
Albert Guisasola ◽  
Evina Katsou ◽  
Juan Antonio Baeza
Keyword(s):  
Wastewater Treatment ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Partial Nitrification ◽  
Biological Nutrient Removal ◽  
N2o Emissions ◽  
Ammonia Oxidizing Bacteria ◽  
N2o Production ◽  
Dynamic Conditions ◽  
Nitrifier Denitrification

Nitrous oxide (N2O), a greenhouse gas with a significant global warming potential, can be produced during the biological nutrient removal in wastewater treatment plants (WWTPs). N2O modelling under dynamic conditions is of vital importance for its mitigation. Following the activated sludge models (ASM) layout, an ASM-type model was developed considering three biological N2O production pathways for a municipal anaerobic/anoxic/aerobic (A2/O) WWTP performing chemical oxygen demand, nitrogen and phosphorus removal. Precisely, the N2O production pathways included were: nitrifier denitrification, hydroxylamine oxidation, and heterotrophic denitrification, with the first two linked to the ammonia oxidizing bacteria (AOB) activity. A stripping effectivity (SE) factor was used to mark the non-ideality of the stripping modelling. With the dissolved oxygen (DO) in the aerobic compartment ranging from 1.8 to 2.5 mg L-1, partial nitrification and high N2O production via nitrifier denitrification occurred. Therefore, low aeration strategies can effectively lead to a low overall carbon footprint only if complete nitrification is guaranteed. After suddenly increasing the influent ammonium load, the AOB had a greater growth compared to the NOB. N2O hotspot was again nitrifier denitrification. Especially under concurring partial nitrification and high stripping (i.e. combination of low DO and high SEs), the highest N2O emission factors were noted.

Bioelectrochemically-assisted nitrogen removal in osmotic membrane bioreactor

2020 ◽  
Author(s):  
You Wu ◽  
Yun Cai ◽  
Yu-Xiang Lu ◽  
Li-Min Zhang ◽  
Xiao-Li Yang ◽  
...  
Keyword(s):  
Microbial Community ◽  
Removal Efficiency ◽  
Nitrogen Removal ◽  
Membrane Bioreactor ◽  
Operation Mode ◽  
Oxygen Demand ◽  
Denitrifying Bacteria ◽  
Future Research ◽  
Ammonia Oxidizing Bacteria ◽  
Nitrite Oxidizing Bacteria

Abstract Nitrogen removal in osmosis membrane bioreactor (OMBR) is important to its applications but remains a challenge. In this study, a bioelectrochemically-assisted (BEA) operation was integrated into the feed side of OMBRs to enhance nitrogen removal, and sodium acetate was served as a draw solute and supplementary carbon source for the growth of denitrifying bacteria due to reversed-solute. The effects of operation mode and influent ammonium (NH4+) concentration were systematically examined. Compared to a conventional OMBR, the integrated BEA-OMBR achieved higher total nitrogen removal efficiency of 98.13%, and chemical oxygen demand removal efficiency of 95.83% with the influent NH4+-N concentration of 39 mg L−1. The sequencing analyses revealed that ammonia-oxidizing bacteria (0–0.04%), nitrite-oxidizing bacteria (0–0.16%), and denitrifying bacteria (1.98–8.65%) were in abundance of the microbial community in the feed/anode side of integrated BEA-OMBR, and thus BEA operation increased the diversity of the microbial community in OMBR. Future research will focus on improving nitrogen removal from a high ammonium strength wastewater by looping anolyte effluent to the cathode. These findings have demonstrated that BEA operation can be an effective approach to improve nitrogen removal in OMBRs toward sustainable wastewater treatment.

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 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.

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.

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