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Richard M Stuetz - One of the best experts on this subject based on the ideXlab platform.
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Effects of Flux Chamber configuration on the sampling of odorous gases emissions
International Journal of Heat and Mass Transfer, 2019Co-Authors: Willian Lemker Andreão, Ademir A. Prata, Jane Meri Santos, Neyval Costa Reis, Richard M StuetzAbstract:Abstract Flux Chambers are commonly used to measure emission rates of odorous compounds at passive liquid surfaces in wastewater treatment plants. Different Flux Chambers configurations are found in the literature and the main concern regards to the mixing inside the Chamber, which is linked to impact on the overall mass transfer between emitting surface and headspace, and the sampling recovery efficiency. However, aspects related to the airflow and mass transfer inside the Chambers influence the measured emission rates. The mass transfer coefficients in the liquid and gas phases are functions of the friction velocity on the liquid surface. This work investigates the airflow and odorous compounds transport (with different Henry’s law constants) inside a Flux Chamber using Computational Fluid Dynamics, to determine the influence of inlet airflow rate (2, 5 and 10 L min−1), inlet configurations (4, 6 and 8 inlet holes) and the inclusion of internal fans on the surface friction velocity and emission rate. The results showed a complex flow inside the Chambers and a concentration field that reaches steady state after 6 residence times. The use of an internal fan promoting downward flow increased turbulence and produced values of friction velocity at the liquid interface closer to those found in the near surface flow in the boundary layer, whereas all other configurations tested showed much lower values of friction velocity. Therefore, the use of a fan is recommended.
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Dynamic Flux Chamber measurements of hydrogen sulfide emission rate from a quiescent surface – A computational evaluation
Chemosphere, 2016Co-Authors: Ademir A. Prata Jr., Sandra P. Beghi, Jane Meri Santos, Neyval Costa Reis, Lya L.c. Vom Marttens, Leovegildo I. Pereira Neto, Ramon S. Martins, Richard M StuetzAbstract:Enclosure devices have been studied and used for research purposes and practical applications in order to measure the emission rate of odorous pollutants from quiescent liquid surfaces to atmosphere. However, important questions remain about the interference of these measuring devices on the actual emission rate. The main concern regarding the use of a Flux Chamber is the fact that odorous compounds can accumulate into the Chamber and yield gas-phase concentration increase inside the equipment, which causes a reduction of the emission rate during the measurement and thus gives an inaccurate local emission rate. Furthermore, the fluid flow inside the Chamber does not reproduce the atmospheric boundary layer flow. This study applied the Computational Fluid Dynamics (CFD) technique in order to investigate the influence of the fluid flow features inside a Flux Chamber on the measured hydrogen sulfide emission rate at quiescent liquid surfaces. The Flux Chamber design and operational conditions are those supported by the United States Environmental Protection Agency (US EPA). The results show that the US EPA Flux Chamber presents a fairly well mixed air phase. However, a trend to stagnation and hydrogen sulfide accumulation near Chamber walls was detected in the computational simulation, which also indicated that the positioning of the sampling tube in relation to the inlet orifices may lead to deviations in the measurement results. CFD results showed that the wall shear and concentration gradients spatially vary at the gas–liquid interface, and friction velocity inside the Chamber does not match typical values of atmospheric flow.
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Dynamic Flux Chamber measurements of hydrogen sulfide emission rate from a quiescent surface--A computational evaluation.
Chemosphere, 2015Co-Authors: Ademir A. Prata, Sandra P. Beghi, Isabella F. Fernandes, Lya L.c. Vom Marttens, Leovegildo I. Pereira Neto, Ramon Martins, Jane Meri Santos, Neyval Costa Reis, Richard M StuetzAbstract:Abstract Enclosure devices have been studied and used for research purposes and practical applications in order to measure the emission rate of odorous pollutants from quiescent liquid surfaces to atmosphere. However, important questions remain about the interference of these measuring devices on the actual emission rate. The main concern regarding the use of a Flux Chamber is the fact that odorous compounds can accumulate into the Chamber and yield gas-phase concentration increase inside the equipment, which causes a reduction of the emission rate during the measurement and thus gives an inaccurate local emission rate. Furthermore, the fluid flow inside the Chamber does not reproduce the atmospheric boundary layer flow. This study applied the Computational Fluid Dynamics (CFD) technique in order to investigate the influence of the fluid flow features inside a Flux Chamber on the measured hydrogen sulfide emission rate at quiescent liquid surfaces. The Flux Chamber design and operational conditions are those supported by the United States Environmental Protection Agency (US EPA). The results show that the US EPA Flux Chamber presents a fairly well mixed air phase. However, a trend to stagnation and hydrogen sulfide accumulation near Chamber walls was detected in the computational simulation, which also indicated that the positioning of the sampling tube in relation to the inlet orifices may lead to deviations in the measurement results. CFD results showed that the wall shear and concentration gradients spatially vary at the gas–liquid interface, and friction velocity inside the Chamber does not match typical values of atmospheric flow.
Charles W. Rice - One of the best experts on this subject based on the ideXlab platform.
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High-frequency pressure variations in the vicinity of a surface CO2 Flux Chamber
Agricultural and Forest Meteorology, 2003Co-Authors: Eugene S. Takle, James R. Brandle, Rodney A. Schmidt, Rick Garcia, Irina V. Litvina, William J. Massman, Xinhua Zhou, Geoffrey Doyle, Charles W. RiceAbstract:We report measurements of 2 Hz pressure fluctuations at and below the soil surface in the vicinity of a surface-based CO 2 Flux Chamber. These measurements were part of a field experiment to examine the possible role of pressure pumping due to atmospheric pressure fluctuations on measurements of surface Fluxes of CO 2. Under the moderate wind speeds, warm temperatures, and dry soil conditions present at the time of our observations, the Chamber had no effect on the pressure field in its near vicinity that could be detected above the level of natural pressure fluctuations in the vicinity. At frequencies at or
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high frequency pressure variations in the vicinity of a surface co2 Flux Chamber
Agricultural and Forest Meteorology, 2003Co-Authors: Eugene S. Takle, James R. Brandle, Rodney A. Schmidt, Rick Garcia, Irina V. Litvina, William J. Massman, Xinhua Zhou, Geoffrey Doyle, Charles W. RiceAbstract:We report measurements of 2 Hz pressure fluctuations at and below the soil surface in the vicinity of a surface-based CO 2 Flux Chamber. These measurements were part of a field experiment to examine the possible role of pressure pumping due to atmospheric pressure fluctuations on measurements of surface Fluxes of CO 2. Under the moderate wind speeds, warm temperatures, and dry soil conditions present at the time of our observations, the Chamber had no effect on the pressure field in its near vicinity that could be detected above the level of natural pressure fluctuations in the vicinity. At frequencies at or <2 Hz, pressure fluctuations easily penetrated the soil to depths of several cm with little attenuation. We conclude that the presence of the Chamber does not introduce pressure perturbations that lead to biases in measurements of surface Fluxes of CO2. © 2002 Elsevier Science B.V. All rights reserved.
Steven V. Fend - One of the best experts on this subject based on the ideXlab platform.
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Importance of Sediment–Water Interactions in Coeur d’Alene Lake, Idaho, USA: Management Implications
Environmental Management, 2003Co-Authors: James S. Kuwabara, Paul F. Woods, William M. Berelson, Laurie S. Balistrieri, James L. Carter, Brent R. Topping, Steven V. FendAbstract:A field study at Coeur d’Alene Lake, Idaho, USA, was conducted between October 1998 and August 2001 to examine the potential importance of sediment–water interactions on contaminant transport and to provide the first direct measurements of the benthic Flux of dissolved solutes of environmental concern in this lake. Because of potential ecological effects, dissolved zinc and orthophosphate were the solutes of primary interest. Results from deployments of an in situ Flux Chamber indicated that benthic Fluxes of dissolved Zn and orthophosphate were comparable in magnitude to riverine inputs. Tracer analyses and benthic-community metrics provided evidence that solute benthic Flux were diffusion-controlled at the Flux-Chamber deployment sites. That is, effects of biomixing (or bioturbation) and ground-water interactions did not strongly influence benthic Flux. Remediation efforts in the river might not produce desired water-quality effects in the lake because imposed shifts in concentration gradients near the sediment–water interface would generate a benthic feedback response. Therefore, development of water-quality models to justify remediation strategies requires consideration of contaminant Flux between the water column and underlying sediment in basins that have been affected by long-term (decadal) anthropogenic activities.
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Importance of sediment-water interactions in Coeur d'Alene Lake, Idaho, USA: management implications.
Environmental management, 2003Co-Authors: James S. Kuwabara, Paul F. Woods, William M. Berelson, James L. Carter, Brent R. Topping, Steven V. Fend, Laurie S. BalistrieriAbstract:A field study at Coeur d’Alene Lake, Idaho, USA, was conducted between October 1998 and August 2001 to examine the potential importance of sediment–water interactions on contaminant transport and to provide the first direct measurements of the benthic Flux of dissolved solutes of environmental concern in this lake. Because of potential ecological effects, dissolved zinc and orthophosphate were the solutes of primary interest. Results from deployments of an in situ Flux Chamber indicated that benthic Fluxes of dissolved Zn and orthophosphate were comparable in magnitude to riverine inputs. Tracer analyses and benthic-community metrics provided evidence that solute benthic Flux were diffusion-controlled at the Flux-Chamber deployment sites. That is, effects of biomixing (or bioturbation) and ground-water interactions did not strongly influence benthic Flux. Remediation efforts in the river might not produce desired water-quality effects in the lake because imposed shifts in concentration gradients near the sediment–water interface would generate a benthic feedback response. Therefore, development of water-quality models to justify remediation strategies requires consideration of contaminant Flux between the water column and underlying sediment in basins that have been affected by long-term (decadal) anthropogenic activities.
Laurie S. Balistrieri - One of the best experts on this subject based on the ideXlab platform.
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Importance of Sediment–Water Interactions in Coeur d’Alene Lake, Idaho, USA: Management Implications
Environmental Management, 2003Co-Authors: James S. Kuwabara, Paul F. Woods, William M. Berelson, Laurie S. Balistrieri, James L. Carter, Brent R. Topping, Steven V. FendAbstract:A field study at Coeur d’Alene Lake, Idaho, USA, was conducted between October 1998 and August 2001 to examine the potential importance of sediment–water interactions on contaminant transport and to provide the first direct measurements of the benthic Flux of dissolved solutes of environmental concern in this lake. Because of potential ecological effects, dissolved zinc and orthophosphate were the solutes of primary interest. Results from deployments of an in situ Flux Chamber indicated that benthic Fluxes of dissolved Zn and orthophosphate were comparable in magnitude to riverine inputs. Tracer analyses and benthic-community metrics provided evidence that solute benthic Flux were diffusion-controlled at the Flux-Chamber deployment sites. That is, effects of biomixing (or bioturbation) and ground-water interactions did not strongly influence benthic Flux. Remediation efforts in the river might not produce desired water-quality effects in the lake because imposed shifts in concentration gradients near the sediment–water interface would generate a benthic feedback response. Therefore, development of water-quality models to justify remediation strategies requires consideration of contaminant Flux between the water column and underlying sediment in basins that have been affected by long-term (decadal) anthropogenic activities.
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Importance of sediment-water interactions in Coeur d'Alene Lake, Idaho, USA: management implications.
Environmental management, 2003Co-Authors: James S. Kuwabara, Paul F. Woods, William M. Berelson, James L. Carter, Brent R. Topping, Steven V. Fend, Laurie S. BalistrieriAbstract:A field study at Coeur d’Alene Lake, Idaho, USA, was conducted between October 1998 and August 2001 to examine the potential importance of sediment–water interactions on contaminant transport and to provide the first direct measurements of the benthic Flux of dissolved solutes of environmental concern in this lake. Because of potential ecological effects, dissolved zinc and orthophosphate were the solutes of primary interest. Results from deployments of an in situ Flux Chamber indicated that benthic Fluxes of dissolved Zn and orthophosphate were comparable in magnitude to riverine inputs. Tracer analyses and benthic-community metrics provided evidence that solute benthic Flux were diffusion-controlled at the Flux-Chamber deployment sites. That is, effects of biomixing (or bioturbation) and ground-water interactions did not strongly influence benthic Flux. Remediation efforts in the river might not produce desired water-quality effects in the lake because imposed shifts in concentration gradients near the sediment–water interface would generate a benthic feedback response. Therefore, development of water-quality models to justify remediation strategies requires consideration of contaminant Flux between the water column and underlying sediment in basins that have been affected by long-term (decadal) anthropogenic activities.
Andy Cole - One of the best experts on this subject based on the ideXlab platform.
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standardization of Flux Chamber and wind tunnel Flux measurements for quantifying volatile organic compound and ammonia emissions from area sources at animal feeding operations
Atmospheric Environment, 2013Co-Authors: David B. Parker, Bryan L Woodbury, Mindy J Spiehs, Steve Trabue, R W Todd, Kenneth D. Casey, Marty B. Rhoades, Andy ColeAbstract:Abstract A variety of portable wind tunnels and Flux Chambers have been used to measure Fluxes of volatile organic compounds (VOC) and ammonia (NH 3 ) at animal feeding operations (AFO). However, there has been little regard to the extreme variation and potential inaccuracies caused by air velocity or sweep air flow rates that are either too low or too high to simulate field conditions. There is a need for correction factors to standardize Flux Chamber and wind tunnel measurements. In this manuscript, we present results of water evaporative Flux and VOC Flux measurements with the EPA Flux Chamber and a small wind tunnel. In the EPA Flux Chamber, water evaporative Flux was positively correlated with sweep air flow rate (SAFR) between 1 and 20 L min −1 ( r 2 = 0.981–0.999) and negatively correlated with sweep air relative humidity between 0 and 80% ( r 2 = 0.982–0.992). Emissions of gas-film controlled compounds like NH 3 and VOC at AFOs were positively correlated with evaporation rates between 0.6 and 2.8 mm d −1 . We demonstrate a simple methodology for standardizing and comparing different Chamber types by measuring water evaporation within the Chamber using a gravimetric mass balance approach under controlled laboratory conditions. A water evaporative Flux ratio correction factor (EFRCF) was used to improve the accuracy of field-measured VOC and NH 3 Chamber Flux measurements. In a field study, both the EPA Flux Chamber (SAFR = 5 L min −1 ) and small wind tunnel (SAFR = 1 L min −1 ) underestimated the true field emissions of VOC, with EFRCFs of 2.42 and 3.84, respectively. EFRCFs are recommended for all but the driest of soil and manure conditions.
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Standardization of Flux Chamber and Wind Tunnel Flux Measurements for Quantifying Emissions from Area Sources at Animal Feeding Operations
2011 Louisville Kentucky August 7 - August 10 2011, 2011Co-Authors: David Parker, Bryan L Woodbury, Mindy J Spiehs, Steve Trabue, R W Todd, Marty B. Rhoades, Jay Ham, Lingshuang Cai, Andy ColeAbstract:A variety of wind tunnels and Flux Chambers have been used to measure Fluxes of volatile organic compounds (VOC) and ammonia (NH3) at animal feeding operations (AFO). However, there has been little regard to the extreme variation and inaccuracy caused by inappropriate air velocity or sweep air flow rates. There is a need to standardize Flux Chamber and wind tunnel measurements. In this paper, we present results of evaporative and VOC Flux measurements with the EPA Flux Chamber and a small wind tunnel. Emissions of gas-film controlled compounds like NH3 and VOC at AFOs are positively correlated with evaporation rates. We propose a simple methodology for standardization and comparison of different Chamber types by measuring water evaporation using a mass balance approach. This same methodology holds promise for correcting field-measured Chamber Flux measurements resulting in more accurate emission estimates.