Mitigating CH4 Emissions in Semi-Aerobic Landfills: Impacts of Operating Conditions on Abundance and Community Structure of Methanotrophs in Cover Soils

2013 ◽  
Vol 23 (7) ◽  
pp. 993-1003 ◽  
Author(s):  
Huai Li
Keyword(s):  
Community Structure ◽  
Operating Conditions ◽  
Ch4 Emissions ◽  
Aerobic Landfills

scholarly journals The capacity of wastewater treatment plants drives bacterial community structure and its assembly

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Young Kyung Kim ◽  
Keunje Yoo ◽  
Min Sung Kim ◽  
Il Han ◽  
Minjoo Lee ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Community Structure ◽  
Bacterial Community ◽  
Activated Sludge ◽  
Community Assembly ◽  
Bacterial Communities ◽  
Wastewater Treatment Plants ◽  
High Capacity ◽  
Operating Conditions ◽  
Rrna Gene

Abstract Bacterial communities in wastewater treatment plants (WWTPs) affect plant functionality through their role in the removal of pollutants from wastewater. Bacterial communities vary extensively based on plant operating conditions and influent characteristics. The capacity of WWTPs can also affect the bacterial community via variations in the organic or nutrient composition of the influent. Despite the importance considering capacity, the characteristics that control bacterial community assembly are largely unknown. In this study, we discovered that bacterial communities in WWTPs in Korea and Vietnam, which differ remarkably in capacity, exhibit unique structures and interactions that are governed mainly by the capacity of WWTPs. Bacterial communities were analysed using 16S rRNA gene sequencing and exhibited clear differences between the two regions, with these differences being most pronounced in activated sludge. We found that capacity contributed the most to bacterial interactions and community structure, whereas other factors had less impact. Co-occurrence network analysis showed that microorganisms from high-capacity WWTPs are more interrelated than those from low-capacity WWTPs, which corresponds to the tighter clustering of bacterial communities in Korea. These results will contribute to the understanding of bacterial community assembly in activated sludge processing.

Linking Microbial Community Dynamics in BIOX® Leaching Tanks to Process Conditions: Integrating Lab and Commercial Experience

2017 ◽  
Vol 262 ◽  
pp. 38-42 ◽  
Author(s):  
Mariette Smart ◽  
Robert J. Huddy ◽  
Catherine J. Edward ◽  
Charl Fourie ◽  
Trust Shumba ◽  
...  
Keyword(s):  
South Africa ◽  
Community Structure ◽  
Microbial Community ◽  
Research University ◽  
Community Dynamics ◽  
Operating Conditions ◽  
Process Conditions ◽  
Significant Shift ◽  
Engineering Research ◽  
Microbial Community Dynamics

In the commercial BIOX® process, an acidophilic mixed bacterial and archaeal community dominated by iron and sulphur oxidising microorganisms is used to facilitate the recovery of precious metals from refractory gold-bearing sulphidic mineral concentrates. Characterisation of the microbial communities associated with commercial BIOX® reactors from four continents revealed a significant shift in the microbial community structure compared to that of the seed culture, maintained at SGS (South Africa). This has motivated more detailed study of the microbial community dynamics in the process. Microbial speciation of a subset of the BIOX® reactors at Fairview mines (Barberton, South Africa) and two laboratory maintained reactors housed at Centre for Bioprocess Engineering Research, University of Cape Town, has been performed tri-annually for three years by quantitative real-time polymerase chain reaction. The laboratory BIOX® culture maintained on Fairview concentrate was dominated by the desired iron oxidiser, Leptospirillum ferriphilum, and sulphur oxidiser, Acidithiobacillus caldus, when operated under standard BIOX® conditions. Shifts in the microbial community as a result of altered operating conditions were transient and did not result in a loss of the microbial diversity of the BIOX® culture. The community structure of the Fairview mines BIOX® reactor tanks showed archaeal dominance of these communities by organisms such as the iron oxidiser Ferroplasma acidiphilum and a Thermoplasma sp. for the period monitored. Shifts in the microbial community were observed across the monitoring period and mapped to changes in performance of the commercial process plant. Understanding the effect of changes in the plant operating conditions on the BIOX® community structure may assist in providing conditions that support the desired microbial consortium for optimal biooxidation to maximize gold recovery.

Impact of inocula and operating conditions on the microbial community structure of two anammox reactors

2014 ◽  
Vol 35 (14) ◽  
pp. 1811-1822 ◽  
Author(s):  
Maria Cristina Monteiro S. Costa ◽  
Luciana Carvalho ◽  
Cintia Dutra Leal ◽  
Marcela França Dias ◽  
Karoline L. Martins ◽  
...  
Keyword(s):  
Community Structure ◽  
Microbial Community ◽  
Microbial Community Structure ◽  
Operating Conditions

scholarly journals Characteristics of the community-structure of A2O processes under different temperature conditions in plateau areas

2020 ◽  
Author(s):  
Yongchen Zong ◽  
Yuanwei Li ◽  
Decai Huang ◽  
Kaiyue Hao ◽  
Guanghua Lu
Keyword(s):  
Community Structure ◽  
Operating Conditions ◽  
Community Diversity ◽  
Nitrifying Bacteria ◽  
Composition Analysis ◽  
Temperature Sensitive ◽  
Colony Structure ◽  
The Common ◽  
Dominant Bacteria ◽  
Study Laboratory

Abstract Background: In this study, laboratory-scale A2O wastewater treatment was performed in Linzhi at an altitude of 3000 meters. Water temperatures were maintained at four operating conditions (25°C, 20°C, 15°C, and 10°C). Sludge in the aerobic tank was assessed by 16SrRNA sequencing and composition analysis. The Phylum, Class, Order, Family, Genus, and Species of the sludge were also confirmed.Results: The bacteria within the sludge showed significant differences at varying temperatures (P<0.05). A significant correlation between the bacteria numbers in anaerobic tanks and anoxic tanks also occurred. Indicators of community richness, community uniformity, community diversity and other areas showed differences. Significant differences in bacteria abundance were also observed and differed to those of previously reported superior community categories and proportions. T-tests were used to identify temperature-sensitive community at each level. Correlation analysis of environmental factors and colony structure further confirmed the association between temperature and colony structure (P<0.05). The removal rates of TP, TN, NH3-N, and COD were all affected by the sample community structure. The variety of colony structure include nitrifying bacteria, denitrifying bacteria, phosphorus accumulating bacteria and other bacterial differed, but their proportions were relatively low. Heatmaps were used to identify species sensitive to temperature, TP, TN, NH3-N, COD at the species level.Conclusions: Amongst the common dominant bacteria at the species level, Bacteroidetes_bacterium_OLB10 was significantly related to temperature. Other common dominant bacteria that were related to temperature metagenome_g__Gordonia, unclassified_f__Burkholderiaceae, uncultured_bacterium_g__norank_f__Saprospiraceae.

scholarly journals Three-Source Partitioning of Methane Emissions from Paddy Soil: Linkage to Methanogenic Community Structure

2019 ◽  
Vol 20 (7) ◽  
pp. 1586 ◽  
Author(s):  
Jing Yuan ◽  
Xiaomei Yi ◽  
Linkui Cao
Keyword(s):  
Community Structure ◽  
Paddy Soil ◽  
Organic Fertilizer ◽  
Fertilizer Treatment ◽  
Rice Soil ◽  
Organic Fertilization ◽  
Soil C ◽  
Methanogenic Community ◽  
Ch4 Emissions ◽  
Native Soil

Identification of the carbon (C) sources of methane (CH4) and methanogenic community structures after organic fertilization may provide a better understanding of the mechanism that regulate CH4 emissions from paddy soils. Based on our previous field study, a pot experiment with isotopic 13C labelling was designed in this study. The objective was to investigate the main C sources for CH4 emissions and the key environmental factor with the application of organic fertilizer in paddies. Results indicated that 28.6%, 64.5%, 0.4%, and 6.5% of 13C was respectively distributed in CO2, the plants, soil, and CH4 at the rice tillering stage. In total, organically fertilized paddy soil emitted 3.51 kg·CH4 ha−1 vs. 2.00 kg·CH4 ha−1 for the no fertilizer treatment. Maximum CH4 fluxes from organically fertilized (0.46 mg·m−2·h−1) and non-fertilized (0.16 mg·m−2·h−1) soils occurred on day 30 (tillering stage). The total percentage of CH4 emissions derived from rice photosynthesis C was 49%, organic fertilizer C < 0.34%, and native soil C > 51%. Therefore, the increased CH4 emissions from paddy soil after organic fertilization were mainly derived from native soil and photosynthesis. The 16S rRNA sequencing showed Methanosarcina (64%) was the dominant methanogen in paddy soil. Organic fertilization increased the relative abundance of Methanosarcina, especially in rhizosphere. Additionally, Methanosarcina sp. 795 and Methanosarcina sp. 1H1 co-occurred with Methanobrevibacter sp. AbM23, Methanoculleus sp. 25XMc2, Methanosaeta sp. HA, and Methanobacterium sp. MB1. The increased CH4 fluxes and labile methanogenic community structure in organically fertilized rice soil were primarily due to the increased soil C, nitrogen, potassium, phosphate, and acetate. These results highlight the contributions of native soil- and photosynthesis-derived C in paddy soil CH4 emissions, and provide basis for more complex investigations of the pathways involved in ecosystem CH4 processes.

The effect of C/N ratio on ammonia oxidising bacteria community structure in a laboratory nitrification-denitrification reactor

2002 ◽  
Vol 46 (1-2) ◽  
pp. 543-550 ◽  
Author(s):  
S.J. Ballinger ◽  
I.M. Head ◽  
T.P. Curtis ◽  
A.R. Godley
Keyword(s):  
Community Structure ◽  
Ammonia Oxidation ◽  
In Situ Hybridisation ◽  
Operating Conditions ◽  
Synthetic Wastewater ◽  
Rrna Gene ◽  
Fish Analysis ◽  
Fluorescence In Situ Hybridisation ◽  
Dgge Analysis ◽  
Quantitative Changes

A laboratory scale reactor operated as a single sludge, denitrification-nitrification bioreactor (DNB), was fed a synthetic wastewater. The effect of the C/N ratio of the influent on the structure of ?-proteobacterial autotrophic ammonia-oxidizing bacterial (AOB) communities was determined by DGGE analysis of 16S rRNA gene fragments amplified using a range of AOB-selective primers. Fluorescence in situ hybridisation (FISH) was used to determine quantitative changes in the AOB communities. When operated at a C/N ratio of 2 the DNB was effective in nitrogen removal and nitrification was measured at approximately 1.0 mg NH4+-N/g dry wt/h. Altering the C/N ratio to 5 resulted in a 50% reduction in nitrification rates. Nitrification was restored to its original level when the C/N ratio was returned to 2. AOB were detected by DGGE analysis of samples from the DNB under all operating conditions but the changes in C/N ratio and nitrification rates were accompanied by changes in the community structure of the AOB. However, quantitative FISH analysis indicated that β-proteobacterial AOB were only present in high numbers (ca. 108 cells/ml) under the original operating conditions with a C/N ratio of 2. β-Proteobacterial AOB could not be detected by FISH when the C/N ratio was 5. When nitrification activity was restored by returning the C/N ratio to 2, β-proteobacterial AOB were still not detected and it is likely that either β-proteobacterial AOB were not responsible for ammonia oxidation or that β-proteobacterial AOB that did not contain the target sites for the range of 4 AOB selective probes used, were present in the reactor.

Cathodoluminescence of Catalyst Crystallites

1982 ◽  
Vol 40 ◽  
pp. 664-665
Author(s):  
E.D. Boyes ◽  
P.L. Gai ◽  
D.B. Darby ◽  
C. Warwick
Keyword(s):  
Defect Density ◽  
Chemical Properties ◽  
Operating Conditions ◽  
Semiconductor Materials ◽  
Environmental Cell ◽  
High Resolution Structure ◽  
Commercially Important ◽  
Crystallographic Defects ◽  
Resolution Structure

The extended crystallographic defects introduced into some oxide catalysts under operating conditions may be a consequence and accommodation of the changes produced by the catalytic activity, rather than always being the origin of the reactivity. Operation without such defects has been established for the commercially important tellurium molybdate system. in addition it is clear that the point defect density and the electronic structure can both have a significant influence on the chemical properties and hence on the effectiveness (activity and selectivity) of the material as a catalyst. SEM/probe techniques more commonly applied to semiconductor materials, have been investigated to supplement the information obtained from in-situ environmental cell HVEM, ultra-high resolution structure imaging and more conventional AEM and EPMA chemical microanalysis.

Comparison of Deterministic and Linear Cosine Spatial Filtering of Transmission Electron Micrographs

1972 ◽  
Vol 30 ◽  
pp. 596-597
Author(s):  
David A. Ansley
Keyword(s):  
Spherical Aberration ◽  
Focal Length ◽  
Chromatic Aberration ◽  
Spatial Filter ◽  
Operating Conditions ◽  
Objective Lens ◽  
List Type ◽  
Spatial Filters ◽  
Transmission Electron ◽  
Wide Range

The coherence of the electron flux of a transmission electron microscope (TEM) limits the direct application of deconvolution techniques which have been used successfully on unmanned spacecraft programs. The theory assumes noncoherent illumination. Deconvolution of a TEM micrograph will, therefore, in general produce spurious detail rather than improved resolution.A primary goal of our research is to study the performance of several types of linear spatial filters as a function of specimen contrast, phase, and coherence. We have, therefore, developed a one-dimensional analysis and plotting program to simulate a wide 'range of operating conditions of the TEM, including adjustment of the:(1) Specimen amplitude, phase, and separation(2) Illumination wavelength, half-angle, and tilt(3) Objective lens focal length and aperture width(4) Spherical aberration, defocus, and chromatic aberration focus shift(5) Detector gamma, additive, and multiplicative noise constants(6) Type of spatial filter: linear cosine, linear sine, or deterministic

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