scholarly journals Detection of Ammonia-oxidizing Bacteria (AOB) in the Biofilm and Suspended Growth Biomass of Fully- and Partially-packed Biological Aerated Filters

10.5772/16443 ◽  
2011 ◽  
Author(s):  
Fatihah Suja
Keyword(s):  
Ammonia Oxidizing Bacteria ◽  
Suspended Growth

Spatial distribution of ammonia-oxidizing bacteria in the biofilm and suspended growth biomass of the full- and partial-bed biological aerated filtersA paper submitted to the Journal of Environmental Engineering and Science.

2009 ◽  
Vol 36 (11) ◽  
pp. 1859-1866 ◽  
Author(s):  
S. Fatihah ◽  
T. Donnelly
Keyword(s):  
Spatial Distribution ◽  
Nitrogen Removal ◽  
Environmental Engineering ◽  
Ammonia Oxidizing Bacteria ◽  
Removal Process ◽  
Suspended Growth

The extent of comparable nitrogen removal in the full- and partial-bed biological aerated reactors needs further microbiological evidence, specifically the existence of ammonia-oxidizing bacteria (AOB). The nitrogen removal process in such systems is typically initiated by chemoliautotrophic ammonia-oxidizing bacteria converting ammonia to nitrite and traces of oxidized nitrogen gases. The formation of a dense biofilm as a result of higher turbulence would account for the higher number of AOB cells enumerated in the biofilm samples from the partial-bed reactor (4.3 × 105 ± 1.9 × 105No. of AOB cells/mL sample) as compared with those from the full-bed reactor (1.5 × 105 ± 8.0 × 104No. of AOB cells/mL sample).

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 Higher Sensitivity of Soil Microbial Network Than Community Structure under Acid Rain

2021 ◽  
Vol 9 (1) ◽  
pp. 118
Author(s):  
Ziqiang Liu ◽  
Hui Wei ◽  
Jiaen Zhang ◽  
Muhammad Saleem ◽  
Yanan He ◽  
...  
Keyword(s):  
Community Structure ◽  
Acid Rain ◽  
Natural Soil ◽  
Available Phosphorus ◽  
Global Changes ◽  
N2o Emissions ◽  
Ammonia Oxidizing Bacteria ◽  
Soil Core ◽  
N Cycle ◽  
Microbial Network

Acid rain (AR), as a global environmental threat, has profoundly adverse effects on natural soil ecosystems. Microorganisms involved in the nitrogen (N) cycle regulate the global N balance and climate stabilization, but little is known whether and how AR influences the structure and complexity of these microbial communities. Herein, we conducted an intact soil core experiment by manipulating the acidity of simulated rain (pH 7.5 (control, CK) vs. pH 4.0 (AR)) in subtropical agricultural soil, to reveal the differences in the structure and complexity of soil nitrifying and denitrifying microbiota using Illumina amplicon sequencing of functional genes (amoA, nirS, and nosZ). Networks of ammonia-oxidizing archaea (AOA) and nirS-carrying denitrifiers in AR treatment were less complex with fewer nodes and lower connectivity, while network of nosZ-carrying denitrifiers in AR treatment had higher complexity and connectivity relative to CK. Supporting this, AR reduced the abundance of keystone taxa in networks of AOA and nirS-carrying denitrifiers, but increased the abundance of keystone taxa in nosZ-carrying denitrifiers network. However, AR did not alter the community structure of AOA, ammonia-oxidizing bacteria (AOB), nirS-, and nosZ-carrying denitrifiers. Moreover, AR did not change soil N2O emissions during the experimental period. AOB community structure significantly correlated with content of soil available phosphorus (P), while the community structures of nirS- and nosZ-carrying denitrifiers both correlated with soil pH and available P content. Soil N2O emission was mainly driven by the nirS-carrying denitrifiers. Our results present new perspective on the impacts of AR on soil N-cycle microbial network complexity and keystone taxa in the context of global changes.

scholarly journals Ammonia-oxidizing archaea are integral to nitrogen cycling in a highly fertile agricultural soil

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Laibin Huang ◽  
Seemanti Chakrabarti ◽  
Jennifer Cooper ◽  
Ana Perez ◽  
Sophia M. John ◽  
...  
Keyword(s):  
Nitrogen Cycle ◽  
Agricultural Soil ◽  
Agricultural Soils ◽  
Ammonia Oxidizing Bacteria ◽  
Central Process ◽  
Soil Nitrification ◽  
Plant Nitrogen ◽  
Ammonia Oxidizing Archaea ◽  
Activity Measurements ◽  
Nitrite Oxidizing Bacteria

AbstractNitrification is a central process in the global nitrogen cycle, carried out by a complex network of ammonia-oxidizing archaea (AOA), ammonia-oxidizing bacteria (AOB), complete ammonia-oxidizing (comammox) bacteria, and nitrite-oxidizing bacteria (NOB). Nitrification is responsible for significant nitrogen leaching and N2O emissions and thought to impede plant nitrogen use efficiency in agricultural systems. However, the actual contribution of each nitrifier group to net rates and N2O emissions remain poorly understood. We hypothesized that highly fertile agricultural soils with high organic matter mineralization rates could allow a detailed characterization of N cycling in these soils. Using a combination of molecular and activity measurements, we show that in a mixed AOA, AOB, and comammox community, AOA outnumbered low diversity assemblages of AOB and comammox 50- to 430-fold, and strongly dominated net nitrification activities with low N2O yields between 0.18 and 0.41 ng N2O–N per µg NOx–N in cropped, fallow, as well as native soil. Nitrification rates were not significantly different in plant-covered and fallow plots. Mass balance calculations indicated that plants relied heavily on nitrate, and not ammonium as primary nitrogen source in these soils. Together, these results imply AOA as integral part of the nitrogen cycle in a highly fertile agricultural soil.

scholarly journals Light as a Novel Inhibitor of Nitrite-Oxidizing Bacteria (NOB) for the Mainstream Partial Nitrification of Wastewater Treatment

Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 346
Author(s):  
Keugtae Kim ◽  
Yong-Gyun Park
Keyword(s):  
Wastewater Treatment ◽  
Blue Light ◽  
Nitrogen Removal ◽  
Municipal Wastewater ◽  
Partial Nitrification ◽  
Biological Nutrient Removal ◽  
Nitrite Accumulation ◽  
Light Illumination ◽  
Ammonia Oxidizing Bacteria ◽  
Nitrite Oxidizing Bacteria

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.

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