Thomas Soerens | Messiah College (original) (raw)
Papers by Thomas Soerens
Each year, nearly 300,000 US college students study abroad and many more go on short-term service... more Each year, nearly 300,000 US college students study abroad and many more go on short-term service trips. The ethic of using engineering skills to serve developing communities abroad is strong in the engineering field. For Christian students and Christian colleges, this service can also integrate with their mission to serve God by serving and evangelizing others, whether motivated by charity, philanthropy, or scriptural mandate. These service programs have impacted students profoundly, often changing the life course of a student. But do they positively impact the targeted communities? Is it efficient to spend 30,000intravelmoneytosendanunskilledstudentteamtodrillawellthatcouldbeconstructedbetterbyalocalwelldrillerfor30,000 in travel money to send an unskilled student team to drill a well that could be constructed better by a local well driller for 30,000intravelmoneytosendanunskilledstudentteamtodrillawellthatcouldbeconstructedbetterbyalocalwelldrillerfor2000? Certainly it’s a great experience for the students, but what about the community? Does it in fact engender passiveness, cynicism, and dependency by the local partners? If we conclude that it’s inefficient, that we should just send money so...
Phosphorus levels in the Illinois River are of great interest to the people of the States of Arka... more Phosphorus levels in the Illinois River are of great interest to the people of the States of Arkansas and Oklahoma. A great deal of effort has been expended to ascertain and modify the phosphorus impacts on the river. An automatic water sampling station was installed on the Illinois River just upstream from the State line in 1996 to accurately quantify the phosphorus in the Arkansas portion of the watershed. This paper summarizes five years worth of phosphorus sampling results at that site. In addition, a simple mass balance for phosphorus in the Illinois River Watershed above the sampling station was developed. The mass balance consisted of determining phosphorus inputs in the drainage area and comparing these to phosphorus outputs, during the same five-year period, allowing for an estimation of phosphorus accumulation. Sampling results showed that phosphorus levels were rapidly increasing in the Illinois River at the State line. Input information showed that over 7 million pounds ...
Ecological Engineering, 2006
Board has adopted numeric total P criteria (0.037 mg P L −1) in Oklahoma's Scenic Rivers, includi... more Board has adopted numeric total P criteria (0.037 mg P L −1) in Oklahoma's Scenic Rivers, including the Illinois River. The US Geological Survey has reported flow-weighted total P concentrations approximately an order of magnitude greater than the newly adopted criterion. Furthermore, elevated dissolved P concentrations have been traced over 45 river kilometers upstream to municipal wastewater discharges in the headwaters of the Illinois River. The point of regulation regarding the total P criteria will be where the Illinois River flows from Arkansas into Oklahoma; however, a small impoundment exists at the Arkansas and Oklahoma border and the states respectively monitor water quality upstream and downstream from this impoundment. The purpose of this study was to evaluate P release from sediments accumulated in this small impoundment. Sediment P release measured in laboratory incubations was as much as 4 mg P m −2 day −1 under aerobic conditions and approximately 15 mg P m −2 day −1 under anaerobic conditions. Sediment equilibrium P concentrations (EPC 0) in laboratory equilibration studies were 0.05-0.20 mg P L −1 , which is greater than the total P criteria for this river in Oklahoma. Thus, it is conceivable that P released from bottom sediments in this small impoundment may, in fact, increase dissolved P concentrations in the Illinois River. The effect of internal P cycling at Lake Frances on P concentration in the Illinois River downstream might be greatest in the near future, because municipal discharges have recently reduced effluent P concentrations.
Applied Engineering in Agriculture, 2005
A pilot scale system was used to evaluate the performance of a membrane microfiltration system, r... more A pilot scale system was used to evaluate the performance of a membrane microfiltration system, rated at 0.1 micron, for the recovery of starches and other solids from rice cooker wastewater produced by a rice processing facility. The first series of tests revealed that a crossflow velocity (V) of 5 m/s and a transmembrane pressure (TMP) of 275 kPa were appropriate for filtration. In the next series of tests, a concentration of almost 9% total solids was achieved, and the logarithmic relationship between permeate flux and concentration was described. Permeate flux rates decreased from over 80 L/m 2 *hour (LMH) for unconcentrated samples to under 20 LMH for the most concentrated samples. The feed flow contained an average of 0.71% total solids and 4395-mg/L biochemical oxygen demand (BOD). The permeate contained under 0.10% total solids and 330 mg/L BOD. A membrane system was sized for the test site based on data from these experiments. A system capable of concentrating 68 L/min of cook water to 5%, 8%, and 10% total solids required a total membrane surface area of 75, 100, and 115 m 2 , respectively. The reduction in sewage expense was predicted to average $10.48 per hour of operation.
2007 Annual Conference & Exposition Proceedings
2019 ASEE Annual Conference & Exposition Proceedings
International Journal for Service Learning in Engineering, Humanitarian Engineering and Social Entrepreneurship
In the summers of 2007, 2008, and 2009 the University of Arkansas (UA) sent 148 students to Beliz... more In the summers of 2007, 2008, and 2009 the University of Arkansas (UA) sent 148 students to Belize for a month to perform service projects as part of a new service learning program in developing countries. During the spring semester, the students enrolled in an interdisciplinary lecture course team-taught by 9 faculty members plus a discipline-specific practicum held on the UA campus. The subsequent summer session was spent in the Dangriga, Belize vicinity with students implementing their service projects developed during the spring semester practicum. Each year eight student teams implemented approximately 12 projects in different disciplinary areas. The UA partnered with Peacework, an international NGO with a long-time presence in Belize and initiatives in many countries worldwide and committed to a minimum of 5 years for projects in Dangriga. The partnership utilized the “village network” concept where these partners worked with the Dangriga community leaders to determine the mul...
J Am Water Resour Assoc, 2003
Resolution of the input GIS data used to parameterize distributed-parameter hydrologic/water qual... more Resolution of the input GIS data used to parameterize distributed-parameter hydrologic/water quality models may affect uncertainty in model outputs and impact the subsequent application of model results in watershed management. In this study we evaluated the impact of varying spatial resolutions of DEM, land use, and soil data (30 x 30 m, 100 x 100 m, 150 x 150 m, 200 x 200 m, 300 x 300 m, 500 x 500 m, and 1,000 x 1,000 m) on the uncertainty of SWAT predicted flow, sediment, NO 3-N, and TP transport. Inputs included measured hydrologic, meteorological, and watershed characteristics as well as water quality data from the Moores Creek watershed in Washington County, Arkansas. The SWAT model output was most affected by input DEM data resolution. A coarser DEM data resolution resulted in decreased representation of watershed area and slope and increased slope length. Distribution of pasture, forest, and urban areas within the watershed was significantly affected at coarser resolution of land use and resulted in significant uncertainty in predicted sediment, NO 3-N, and TP output. Soils data resolution had no significant effect on flow and NO 3-N predictions; however, sediment was overpredicted by 26 percent, and TP was underpredicted by 26 percent at 1,000 m resolution. This may be due to change in relative distribution of various hydrologic soils groups (HSGs) in the watershed. Minimum resolution for input GIS data to achieve less than 10 percent model output error depended upon the output variable of interest. For flow, sediment, NO 3-N, and TP predictions, minimum DEM data resolution should range from 30 to 300 m, whereas minimum land use and soils data resolution should range from 300 to 500 m.
This study investigated the precision and accuracy of the two load calculation techniques. The st... more This study investigated the precision and accuracy of the two load calculation techniques. The study compared total phosphorus loads calculated by integration of Arkansas Water Resources Center (AWRC) intensive sampling data to loads calculated by a regression technique (rating curve) using fewer data. The 1998 AWRC dataset from the Illinois River at Arkansas Highway 59 was sub-sampled in a manner to simulate fixed period monitoring schemes supplemented with storm sampling. The ESTIMATOR software program was used to calculate loads. These loads were compared to the integrated load. The error of the integrated load when the variation in concentration between samples is not linear and the sensitivity of the integrated load to sampling interval were also investigated. The results show that the central tendency of the ESTIMATOR loads is accurate when storm data are included, but that the 95% confidence interval represents up to +/-30-40% difference from the integrated load for individual estimates. More frequent sampling and more samples lead to more accurate loads. The results indicate that the central tendency of load estimates would be accurate for a method that uses a regression model with 32 or more samples including storm samples.
Accurate measurements of nutrient and pollution loads in streams are critical for detecting water... more Accurate measurements of nutrient and pollution loads in streams are critical for detecting water quality trends, determining the impacts of non point source (NPS) pollution, and developing TMDLs. Much or most of the load in a stream occurs during surface runoff events (storms). For several years, we at the Arkansas Water Resources Center (AWRC) have sampled and calculated nutrient loads
Journal of Water, Sanitation and Hygiene for Development, 2015
Migration and Fate of Pollutants in Soils and Subsoils, 1993
Water Environment Research, 1993
Water Environment Research, 1994
ABSTRACT
Phosphorus levels in the Illinois River are of great interest to the people of the States of Arka... more Phosphorus levels in the Illinois River are of great interest to the people of the States of Arkansas and Oklahoma. A great deal of effort has been expended to ascertain and modify the phosphorus impacts on the river. An automatic water sampling station was installed on the Illinois River just upstream from the State line in 1996 to accurately quantify the phosphorus in the Arkansas portion of the watershed. This paper summarizes five years worth of phosphorus sampling results at that site. In addition, a simple mass balance for phosphorus in the Illinois River Watershed above the sampling station was developed. The mass balance consisted of determining phosphorus inputs in the drainage area and comparing these to phosphorus outputs, during the same five-year period, allowing for an estimation of phosphorus accumulation. Sampling results showed that phosphorus levels were rapidly increasing in the Illinois River at the State line. Input information showed that over 7 million pounds of phosphorus were discharged into the 575 square mile basin annually. Mass balance calculations indicated that the point source discharges were responsible for up to 43% of the phosphorus in the river. The calculations indicate that only 4% of the phosphorus applied in the watershed reached the river annually. The remaining 96% accumulated in the watershed at an average rate of 8 kg per pasture acre per year. The effect of point source reductions was investigated and resulting mean concentrations were compared to a 0.037 mg/l in-stream phosphorus limit recently adopted by the State of Oklahoma.
A major challengein ground water remediation is locating nonaqueous phase liquids (NAPLs).Partiti... more A major challengein ground water remediation is locating nonaqueous phase liquids (NAPLs).Partitioning tracers can be used to identifyNAPL sources between injection and extraction wells.NAPLs are only slightly soluble in water, pose a long- term source ofgroundwater contamination, and can be difficult to remove. The complexityof recovery processes requires the development of new technologies that guarantee costeffectivemethods for locating and quantifyingNAPLs.
The development of total maximum daily loads (TMDLs) requires evaluating existing constituent loa... more The development of total maximum daily loads (TMDLs) requires evaluating existing constituent loads in streams. Accurate estimates of constituent loads are needed to calibrate watershed and reservoir models for TMDL development. The best approach to estimate constituent loads is high frequency sampling, particularly during storm events, and mass integration of constituents passing a point in a stream. Most often, resources
Each year, nearly 300,000 US college students study abroad and many more go on short-term service... more Each year, nearly 300,000 US college students study abroad and many more go on short-term service trips. The ethic of using engineering skills to serve developing communities abroad is strong in the engineering field. For Christian students and Christian colleges, this service can also integrate with their mission to serve God by serving and evangelizing others, whether motivated by charity, philanthropy, or scriptural mandate. These service programs have impacted students profoundly, often changing the life course of a student. But do they positively impact the targeted communities? Is it efficient to spend 30,000intravelmoneytosendanunskilledstudentteamtodrillawellthatcouldbeconstructedbetterbyalocalwelldrillerfor30,000 in travel money to send an unskilled student team to drill a well that could be constructed better by a local well driller for 30,000intravelmoneytosendanunskilledstudentteamtodrillawellthatcouldbeconstructedbetterbyalocalwelldrillerfor2000? Certainly it’s a great experience for the students, but what about the community? Does it in fact engender passiveness, cynicism, and dependency by the local partners? If we conclude that it’s inefficient, that we should just send money so...
Phosphorus levels in the Illinois River are of great interest to the people of the States of Arka... more Phosphorus levels in the Illinois River are of great interest to the people of the States of Arkansas and Oklahoma. A great deal of effort has been expended to ascertain and modify the phosphorus impacts on the river. An automatic water sampling station was installed on the Illinois River just upstream from the State line in 1996 to accurately quantify the phosphorus in the Arkansas portion of the watershed. This paper summarizes five years worth of phosphorus sampling results at that site. In addition, a simple mass balance for phosphorus in the Illinois River Watershed above the sampling station was developed. The mass balance consisted of determining phosphorus inputs in the drainage area and comparing these to phosphorus outputs, during the same five-year period, allowing for an estimation of phosphorus accumulation. Sampling results showed that phosphorus levels were rapidly increasing in the Illinois River at the State line. Input information showed that over 7 million pounds ...
Ecological Engineering, 2006
Board has adopted numeric total P criteria (0.037 mg P L −1) in Oklahoma's Scenic Rivers, includi... more Board has adopted numeric total P criteria (0.037 mg P L −1) in Oklahoma's Scenic Rivers, including the Illinois River. The US Geological Survey has reported flow-weighted total P concentrations approximately an order of magnitude greater than the newly adopted criterion. Furthermore, elevated dissolved P concentrations have been traced over 45 river kilometers upstream to municipal wastewater discharges in the headwaters of the Illinois River. The point of regulation regarding the total P criteria will be where the Illinois River flows from Arkansas into Oklahoma; however, a small impoundment exists at the Arkansas and Oklahoma border and the states respectively monitor water quality upstream and downstream from this impoundment. The purpose of this study was to evaluate P release from sediments accumulated in this small impoundment. Sediment P release measured in laboratory incubations was as much as 4 mg P m −2 day −1 under aerobic conditions and approximately 15 mg P m −2 day −1 under anaerobic conditions. Sediment equilibrium P concentrations (EPC 0) in laboratory equilibration studies were 0.05-0.20 mg P L −1 , which is greater than the total P criteria for this river in Oklahoma. Thus, it is conceivable that P released from bottom sediments in this small impoundment may, in fact, increase dissolved P concentrations in the Illinois River. The effect of internal P cycling at Lake Frances on P concentration in the Illinois River downstream might be greatest in the near future, because municipal discharges have recently reduced effluent P concentrations.
Applied Engineering in Agriculture, 2005
A pilot scale system was used to evaluate the performance of a membrane microfiltration system, r... more A pilot scale system was used to evaluate the performance of a membrane microfiltration system, rated at 0.1 micron, for the recovery of starches and other solids from rice cooker wastewater produced by a rice processing facility. The first series of tests revealed that a crossflow velocity (V) of 5 m/s and a transmembrane pressure (TMP) of 275 kPa were appropriate for filtration. In the next series of tests, a concentration of almost 9% total solids was achieved, and the logarithmic relationship between permeate flux and concentration was described. Permeate flux rates decreased from over 80 L/m 2 *hour (LMH) for unconcentrated samples to under 20 LMH for the most concentrated samples. The feed flow contained an average of 0.71% total solids and 4395-mg/L biochemical oxygen demand (BOD). The permeate contained under 0.10% total solids and 330 mg/L BOD. A membrane system was sized for the test site based on data from these experiments. A system capable of concentrating 68 L/min of cook water to 5%, 8%, and 10% total solids required a total membrane surface area of 75, 100, and 115 m 2 , respectively. The reduction in sewage expense was predicted to average $10.48 per hour of operation.
2007 Annual Conference & Exposition Proceedings
2019 ASEE Annual Conference & Exposition Proceedings
International Journal for Service Learning in Engineering, Humanitarian Engineering and Social Entrepreneurship
In the summers of 2007, 2008, and 2009 the University of Arkansas (UA) sent 148 students to Beliz... more In the summers of 2007, 2008, and 2009 the University of Arkansas (UA) sent 148 students to Belize for a month to perform service projects as part of a new service learning program in developing countries. During the spring semester, the students enrolled in an interdisciplinary lecture course team-taught by 9 faculty members plus a discipline-specific practicum held on the UA campus. The subsequent summer session was spent in the Dangriga, Belize vicinity with students implementing their service projects developed during the spring semester practicum. Each year eight student teams implemented approximately 12 projects in different disciplinary areas. The UA partnered with Peacework, an international NGO with a long-time presence in Belize and initiatives in many countries worldwide and committed to a minimum of 5 years for projects in Dangriga. The partnership utilized the “village network” concept where these partners worked with the Dangriga community leaders to determine the mul...
J Am Water Resour Assoc, 2003
Resolution of the input GIS data used to parameterize distributed-parameter hydrologic/water qual... more Resolution of the input GIS data used to parameterize distributed-parameter hydrologic/water quality models may affect uncertainty in model outputs and impact the subsequent application of model results in watershed management. In this study we evaluated the impact of varying spatial resolutions of DEM, land use, and soil data (30 x 30 m, 100 x 100 m, 150 x 150 m, 200 x 200 m, 300 x 300 m, 500 x 500 m, and 1,000 x 1,000 m) on the uncertainty of SWAT predicted flow, sediment, NO 3-N, and TP transport. Inputs included measured hydrologic, meteorological, and watershed characteristics as well as water quality data from the Moores Creek watershed in Washington County, Arkansas. The SWAT model output was most affected by input DEM data resolution. A coarser DEM data resolution resulted in decreased representation of watershed area and slope and increased slope length. Distribution of pasture, forest, and urban areas within the watershed was significantly affected at coarser resolution of land use and resulted in significant uncertainty in predicted sediment, NO 3-N, and TP output. Soils data resolution had no significant effect on flow and NO 3-N predictions; however, sediment was overpredicted by 26 percent, and TP was underpredicted by 26 percent at 1,000 m resolution. This may be due to change in relative distribution of various hydrologic soils groups (HSGs) in the watershed. Minimum resolution for input GIS data to achieve less than 10 percent model output error depended upon the output variable of interest. For flow, sediment, NO 3-N, and TP predictions, minimum DEM data resolution should range from 30 to 300 m, whereas minimum land use and soils data resolution should range from 300 to 500 m.
This study investigated the precision and accuracy of the two load calculation techniques. The st... more This study investigated the precision and accuracy of the two load calculation techniques. The study compared total phosphorus loads calculated by integration of Arkansas Water Resources Center (AWRC) intensive sampling data to loads calculated by a regression technique (rating curve) using fewer data. The 1998 AWRC dataset from the Illinois River at Arkansas Highway 59 was sub-sampled in a manner to simulate fixed period monitoring schemes supplemented with storm sampling. The ESTIMATOR software program was used to calculate loads. These loads were compared to the integrated load. The error of the integrated load when the variation in concentration between samples is not linear and the sensitivity of the integrated load to sampling interval were also investigated. The results show that the central tendency of the ESTIMATOR loads is accurate when storm data are included, but that the 95% confidence interval represents up to +/-30-40% difference from the integrated load for individual estimates. More frequent sampling and more samples lead to more accurate loads. The results indicate that the central tendency of load estimates would be accurate for a method that uses a regression model with 32 or more samples including storm samples.
Accurate measurements of nutrient and pollution loads in streams are critical for detecting water... more Accurate measurements of nutrient and pollution loads in streams are critical for detecting water quality trends, determining the impacts of non point source (NPS) pollution, and developing TMDLs. Much or most of the load in a stream occurs during surface runoff events (storms). For several years, we at the Arkansas Water Resources Center (AWRC) have sampled and calculated nutrient loads
Journal of Water, Sanitation and Hygiene for Development, 2015
Migration and Fate of Pollutants in Soils and Subsoils, 1993
Water Environment Research, 1993
Water Environment Research, 1994
ABSTRACT
Phosphorus levels in the Illinois River are of great interest to the people of the States of Arka... more Phosphorus levels in the Illinois River are of great interest to the people of the States of Arkansas and Oklahoma. A great deal of effort has been expended to ascertain and modify the phosphorus impacts on the river. An automatic water sampling station was installed on the Illinois River just upstream from the State line in 1996 to accurately quantify the phosphorus in the Arkansas portion of the watershed. This paper summarizes five years worth of phosphorus sampling results at that site. In addition, a simple mass balance for phosphorus in the Illinois River Watershed above the sampling station was developed. The mass balance consisted of determining phosphorus inputs in the drainage area and comparing these to phosphorus outputs, during the same five-year period, allowing for an estimation of phosphorus accumulation. Sampling results showed that phosphorus levels were rapidly increasing in the Illinois River at the State line. Input information showed that over 7 million pounds of phosphorus were discharged into the 575 square mile basin annually. Mass balance calculations indicated that the point source discharges were responsible for up to 43% of the phosphorus in the river. The calculations indicate that only 4% of the phosphorus applied in the watershed reached the river annually. The remaining 96% accumulated in the watershed at an average rate of 8 kg per pasture acre per year. The effect of point source reductions was investigated and resulting mean concentrations were compared to a 0.037 mg/l in-stream phosphorus limit recently adopted by the State of Oklahoma.
A major challengein ground water remediation is locating nonaqueous phase liquids (NAPLs).Partiti... more A major challengein ground water remediation is locating nonaqueous phase liquids (NAPLs).Partitioning tracers can be used to identifyNAPL sources between injection and extraction wells.NAPLs are only slightly soluble in water, pose a long- term source ofgroundwater contamination, and can be difficult to remove. The complexityof recovery processes requires the development of new technologies that guarantee costeffectivemethods for locating and quantifyingNAPLs.
The development of total maximum daily loads (TMDLs) requires evaluating existing constituent loa... more The development of total maximum daily loads (TMDLs) requires evaluating existing constituent loads in streams. Accurate estimates of constituent loads are needed to calibrate watershed and reservoir models for TMDL development. The best approach to estimate constituent loads is high frequency sampling, particularly during storm events, and mass integration of constituents passing a point in a stream. Most often, resources