scholarly journals Ammonia concentration modeling based on retained gas sampler data

1997 ◽  
Author(s):  
G. Terrones ◽  
B.J. Palmer ◽  
J.M. Cuta
Keyword(s):  
Ammonia Concentration ◽  
Gas Sampler

Respiratory Ammonia Output and Blood Ammonia Concentration During Incremental Exercise

1999 ◽  
Vol 20 (02) ◽  
pp. 71-77
Author(s):  
W. Ament ◽  
J. Huizenga ◽  
E. Kort ◽  
T. Mark ◽  
R. Grevink ◽  
...  
Keyword(s):  
Ammonia Concentration ◽  
Incremental Exercise ◽  
Blood Ammonia

Changes in the Shape and Properties of the Precursor of the Rich-Ni Cathode Materials by Ammonia Concentration

2020 ◽  
Vol 30 (11) ◽  
pp. 636-640
Author(s):  
Seonhye Park ◽  
Soonhyun Hong ◽  
Hyeonggwon Jeon ◽  
Chunjoong Kim
Keyword(s):  
Cathode Materials ◽  
Ammonia Concentration ◽  
The Rich

Effect of Aeration on Fresh and Aged Municipal Solid Waste in a Simulated Landfill Bioreactor

2004 ◽  
Vol 39 (3) ◽  
pp. 223-229 ◽  
Author(s):  
Mostafa A. Warith ◽  
Graham J. Takata
Keyword(s):  
Municipal Solid Waste ◽  
Solid Waste ◽  
Ammonia Concentration ◽  
Air Injection ◽  
Bioreactor Landfills ◽  
Time To Stabilization ◽  
High Ammonia ◽  
Simulated Landfill ◽  
Term Monitoring

Abstract Municipal solid waste (MSW) is slow to stabilize under conventional anaerobic landfill conditions, demanding long-term monitoring and pollution control. Provision of aerobic conditions offers several advantages including accelerated leachate stabilization, increased landfill airspace recovery and a reduction in greenhouse gas emissions. Air injection was applied over 130 days to bench-scale bioreactors containing fresh and aged MSW representative of newly constructed and pre-existing landfill conditions. In the fresh MSW simulation bioreactors, aeration reduced the average time to stabilization of leachate pH by 46 days, TSS by 42 days, TDS by 84 days, BOD5 by 46 days and COD by 32 days. In addition, final leachate concentrations were consistently lower in aerated test cells. There was no indication of a gradual decrease in the concentration of ammonia, and it is likely this high ammonia concentration would continue to be problematic in bioreactor landfill applications. This study focussed only on biodegradability of organics in the solid waste. The concentrations of the nonreactive or conservative substances such as chloride and/or heavy metals remain in the bioreactor landfills due to the continuous recirculation of leachate. The results of this study demonstrate the potential for air injection to accelerate stabilization of municipal solid waste, with greatest influence on fresh waste with a high biodegradable organic fraction.

Upgrading effluent quality for lagoon-based systems

1995 ◽  
Vol 31 (12) ◽  
pp. 379-387 ◽  
Author(s):  
Henryk Melcer ◽  
Brian Evans ◽  
Stephen G. Nutt ◽  
Anthony Ho
Keyword(s):  
Urban Communities ◽  
Ammonia Concentration ◽  
Sand Filters ◽  
Plant Operation ◽  
Capital Costs ◽  
Effluent Quality ◽  
Waste Sludge ◽  
Best Available Technology ◽  
Available Technology ◽  
Aeration Plant

To establish Best Available Technology Economically Achievable (BATEA) in non-urban communities which presently use conventional lagoon technology, an investigation was undertaken to evaluate alternatives which can be used to improve lagoon effluent and establish costs. Evaluated were the “Sutton” and the intermittent sand filtration or “New Hamburg” processes. The Sutton concept consists of a nitrifying extended-aeration plant followed by polishing lagoons, with waste sludge discharged into the lagoons. The New Hamburg concept consists of aerated or facultative lagoons, with the lagoon effluent sprayed intermittently over sand filters. The Sutton plants produce an improved effluent quality relative to conventional facultative lagoons in terms of BOD5 and TSS concentrations. Increases in ammonia concentration across the polishing pond occur after 5-7 years of plant operation, suggesting a need to implement a regular program of sludge removal from the lagoon. The New Hamburg process results in a significant improvement in effluent quality in terms of BOD5, TSS, TP, TKN, NH3-N and H2S concentrations. Approximate capital costs for upgrading the existing conventional lagoons in Ontario to Sutton and New Hamburg process facilities are estimated at US $221 million and US $93 million, respectively.

Modeling and risk analysis of bromate formation from ozonation of bromide-containing waters

1996 ◽  
Vol 34 (7-8) ◽  
pp. 79-85 ◽  
Author(s):  
Rengao Song ◽  
Roger Minear ◽  
Paul Westerhoff ◽  
Gary Amy
Keyword(s):  
Water Quality ◽  
Risk Analysis ◽  
Ammonia Concentration ◽  
Quality Characteristics ◽  
The Other ◽  
High Ph ◽  
Treatment Processes ◽  
Ozone Dose ◽  
Other Hand

Empirical bromate formation models were developed from batch ozonation data to simulate the effects of important water quality characteristics and treatment processes on bromate formation. Bromate formation was favored at high pH, bromide concentration, alkalinity, and ozone dose. On the other hand, increasing DOC and ammonia concentration decreased bromate formation. Validation of the bromate models demonstrated that the models accurately simulated bromate formation. Risk analysis of bromate formation was performed on 5 utilities in which ozone was used, and it was concluded that under typical ozonation conditions, the associated risk related to bromate formation could be as high as 10−3.

scholarly journals Emission of harmful gases from animal production in Poland

2021 ◽  
Vol 193 (6) ◽  
Author(s):  
Kamila Mazur ◽  
Kamil Roman ◽  
Witold Jan Wardal ◽  
Kinga Borek ◽  
Jan Barwicki ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Ammonia Concentration ◽  
Herd Size ◽  
Animal Production ◽  
Ammonia Emission ◽  
Emission Rates ◽  
Housing Systems ◽  
Air Exchange Rate ◽  
Microclimate Conditions ◽  
Air Exchange

AbstractThe aim of the study was to present the scale of greenhouse gas emissions from animal production, and to provide test results from different housing systems. In three free stall buildings, two with slurry in deep channels and one with cattle in cubicles staying on shallow litter concentration of ammonia and carbon dioxide were measured in summer season by using dedicated equipment from Industrial Scientific Research. Air exchange was calculated on the base of balance carbon dioxide method. This method was used in order to estimate the air flow rate. Concentrations of ammonia and CO2 were measured as the base for air exchange and ammonia emission rates. Ammonia emissions were product of ammonia concentration and air exchange rate. Temperature and relative humidity were measured to establish microclimate conditions in buildings tested to show the overall microclimatic situation in buildings. Differences between ammonia emission rates were observed in both housing systems. The highest ammonia emission rate was equal to 2.75 g·h−1·LU−1 in well-ventilated cattle barn with the largest herd size.

scholarly journals Short- and Branched-Chain Fatty Acids as Fecal Markers for Microbiota Activity in Vegans and Omnivores

Nutrients ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 1808
Author(s):  
Iris Trefflich ◽  
Stefan Dietrich ◽  
Annett Braune ◽  
Klaus Abraham ◽  
Cornelia Weikert
Keyword(s):  
Fatty Acids ◽  
Ammonia Concentration ◽  
Cross Sectional Study ◽  
Vegan Diet ◽  
Microbiota Composition ◽  
Cross Sectional ◽  
Branched Chain Fatty Acids ◽  
Branched Chain ◽  
Fecal Ph ◽  
Chain Fatty Acids

A vegan diet could impact microbiota composition and bacterial metabolites like short-chain (SCFA) and branched-chain fatty acids (BCFA). The aim of this study was to compare the concentrations of SCFA, BCFA, ammonia, and fecal pH between vegans and omnivores. In this cross-sectional study (vegans n = 36; omnivores n = 36), microbiota composition, fecal SCFA, BCFA, and ammonia concentrations and pH were analyzed in complete stool samples. A random forest regression (RFR) was used to identify bacteria predicting SCFA/BCFA concentrations in vegans and omnivores. No significant differences in SCFA and BCFA concentrations were observed between vegans and omnivores. Fecal pH (p = 0.005) and ammonia concentration (p = 0.01) were significantly lower in vegans than in omnivores, while fiber intake was higher (p < 0.0001). Shannon diversity was higher in omnivores compared to vegans on species level (p = 0.04) only. In vegans, a cluster of Faecalibacterium prausnitzii, Prevotella copri, Dialister spp., and Eubacterium spp. was predictive for SCFA and BCFA concentrations. In omnivores, Bacteroides spp., Clostridium spp., Ruminococcus spp., and Prevotella copri were predictive. Though SCFA and BCFA did not differ between vegans and omnivores, the results of the RFR suggest that bacterial functionality may be adapted to varying nutrient availability in these diets.

scholarly journals Nitrate-dominated PM<sub>2.5</sub> and elevation of particle pH observed in urban Beijing during the winter of 2017

2020 ◽  
Vol 20 (8) ◽  
pp. 5019-5033 ◽  
Author(s):  
Yuning Xie ◽  
Gehui Wang ◽  
Xinpei Wang ◽  
Jianmin Chen ◽  
Yubao Chen ◽  
...  
Keyword(s):  
Atmospheric Aerosols ◽  
Ammonia Concentration ◽  
Historical Record ◽  
Molar Ratio ◽  
Effective Control ◽  
Nitrate Content ◽  
Chinese Government ◽  
Low Level ◽  
The Impact ◽  
Pollution Episodes

Abstract. The Chinese government has exerted strict emission controls to mitigate air pollution since 2013, which has resulted in significant decreases in the concentrations of air pollutants such as SO2. Strict pollution control actions also reduced the average PM2.5 concentration to the low level of 39.7 µg m−3 in urban Beijing during the winter of 2017. To investigate the impact of such changes on the physiochemical properties of atmospheric aerosols in China, we conducted a comprehensive observation focusing on PM2.5 in Beijing during the winter of 2017. Compared with the historical record (2014–2017), SO2 decreased to the low level of 3.2 ppbv in the winter of 2017, but the NO2 level was still high (21.4 ppbv in the winter of 2017). Accordingly, the contribution of nitrate (23.0 µg m−3) to PM2.5 far exceeded that of sulfate (13.1 µg m−3) during the pollution episodes, resulting in a significant increase in the nitrate-to-sulfate molar ratio. The thermodynamic model (ISORROPIA II) calculation results showed that during the PM2.5 pollution episodes particle pH increased from 4.4 (moderate acidic) to 5.4 (more neutralized) when the molar ratio of nitrate to sulfate increased from 1 to 5, indicating that aerosols were more neutralized as the nitrate content elevated. Controlled variable tests showed that the pH elevation should be attributed to nitrate fraction increase other than crustal ion and ammonia concentration increases. Based on the results of sensitivity tests, future prediction for the particle acidity change was discussed. We found that nitrate-rich particles in Beijing at low and moderate humid conditions (RH: 20 %–50 %) can absorb twice the amount of water that sulfate-rich particles can, and the nitrate and ammonia with higher levels have synergetic effects, rapidly elevating particle pH to merely neutral (above 5.6). As moderate haze events might occur more frequently under abundant ammonia and nitrate-dominated PM2.5 conditions, the major chemical processes during haze events and the control target should be re-evaluated to obtain the most effective control strategy.

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