Benjamin Stanford | University of North Carolina at Chapel Hill (original) (raw)
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Papers by Benjamin Stanford
Proceedings of the Water Environment Federation, 2010
ABSTRACT Measurable levels of endocrine disrupting compounds (EDCs) and pharmaceutically active c... more ABSTRACT Measurable levels of endocrine disrupting compounds (EDCs) and pharmaceutically active compounds have been detected in septic systems at concentrations well above those shown to cause sexual and developmental abnormalities in vertebrate and invertebrate aquatic species. Specifically, compounds such as steroid hormones and nonionic surfactant metabolites (nonylphenols) are of particular interest because of their widespread use, high level of potency at low concentrations, and ubiquity in wastewaters. Although a few studies indicate that some of these EDCs could be partially removed or transformed during sewage and septic treatment, many of these compounds are still being found in the environment and in drinking water supplies. The results of our research indicate that using combinations of aerobic and anaerobic sand filters or sub-surface flow wetlands in on-site wastewater treatment systems can improve the overall quality of the final effluent and drastically reduces the concentration of steroid estrogens, nonylphenols, and estrogenic activity. Furthermore, the results indicate that the quality of treated effluent impacts the rate of transport and biotransformation of the steroid estrogens through soils after discharge from the on-site wastewater treatment systems. Thus, traditional systems with only a main tank and/or pump tank discharge relatively poor quality water (e.g., high TOC, high ammonia) with high EDC concentrations and estrogenic activity and has the potential to facilitate transport of such compounds to the groundwater environment. This presentation will highlight the key points of our findings among five full scale on-site wastewater treatment and non-potable reuse systems plus the implications of a bench-scale soil transport study.
Journal of Water Supply: Research and Technology—AQUA, 2014
Proceedings of the Water Environment Federation, 2013
The analysis of endocrine disrupting compounds (EDCs) and pharmaceutical and personal care produc... more The analysis of endocrine disrupting compounds (EDCs) and pharmaceutical and personal care products (PPCP), present at trace level in surface waters, is often expensive, time-consuming, and complex. Implementing effective monitoring strategies for these compounds is essential to determine the types of analytes, sampling locations, and sampling frequencies. Multivariate analyses were used to investigate the patterns of EDCs and PPCPs in Lake Mead, Nevada, for these purposes. The results of cluster analysis and principal component analysis to identify the patterns among compounds demonstrated that selected pharmaceuticals tended to be present together with each other, whereas hormones did not show patterns with other compounds. The results of cluster analysis and discriminant analysis to investigate the spatial variation of EDCs and PPCPs eliminated redundant sampling locations, verifying the current selection of sampling locations in Lake Mead. The results of autocorrelation provided optimal sampling frequencies for EDCs and PPCPs, suggesting either monthly or quarterly monitoring of these compounds in Lake Mead. The patterns of the compounds could be site specific; depending on weather and hydrological conditions of the water systems, but this study's approaches will facilitate effective assessment and monitoring of EDCs and PPCPs in surface water.
Proceedings of the Water Environment Federation, 2013
ABSTRACT The additional removal of trace organic contaminants (TOrCs) provided by advanced water ... more ABSTRACT The additional removal of trace organic contaminants (TOrCs) provided by advanced water and wastewater treatment inevitably requires additional financial costs, which must be estimated to support utility planning and compare alternatives. This study presents conceptual-level (Class 4) capital and annual operations and maintenance (O&M) cost curve equations to aid evaluations of advanced treatment trains for water reuse. The cost curve equations are broadly applicable to the water reuse community, particularly those interested in ozone-based treatment trains. Unit processes include microfiltration or ultrafiltration membranes (MF/UF), nanofiltration or reverse osmosis membranes (NF/RO), ozone (with or without hydrogen peroxide, H2O2), ultraviolet (UV) treatment with H2O2 (UV/H2O2), and biological activated carbon (BAC); all cost curves are for a unit process and can be added together to obtain costs for a combined treatment train. The cost curves indicate that at all plant capacities (1 to 500 MGD), membrane treatment (e.g., MF or RO) represents the highest cost unit process, ozone the least, and BAC or UV/H2O2 fall in between. Additionally, the relationship between ozone dose and TOrC removal is discussed with a demonstration of how costs change with increasing ozone dose to achieve desired TOrC destruction.
IDA Journal of Desalination and Water Reuse, 2011
IDA Journal of Desalination and Water Reuse, 2012
The combination of microfiltration (MF) and reverse osmosis (RO) has become an accepted engineeri... more The combination of microfiltration (MF) and reverse osmosis (RO) has become an accepted engineering practice in the treatment of secondary effluent to levels allowable for common and advanced reuse applications. There are several municipalities in the United States and abroad that now utilize this practice on a large scale.
Water Research, 2010
Nonthermal plasma (NTP) Trace organic compound Pharmaceutical Endocrine disrupting compound (EDC)... more Nonthermal plasma (NTP) Trace organic compound Pharmaceutical Endocrine disrupting compound (EDC) a b s t r a c t
Water Research, 2012
Keywords: N-Nitrosodimethylamine (NDMA) the significance of the potential for direct NDMA formati... more Keywords: N-Nitrosodimethylamine (NDMA) the significance of the potential for direct NDMA formation during oxidation in reuse applications. ª (S.A. Snyder).
Journal - American Water Works Association, 2014
ABSTRACT Many water utilities have recently initiated or are considering initiating monitoring pr... more ABSTRACT Many water utilities have recently initiated or are considering initiating monitoring programs to establish baseline contaminant concentrations of endocrine-disrupting compounds (EDCs) and pharmaceuticals/personal care products (PPCPs) in their water supply. Unfortunately, monitoring sites and sampling frequency have often been conducted without regard to end use of the data, loading dynamics, or environmental behavior of trace contaminants. This article provides an a posteriori analysis of more than eight years of monitoring data from Lake Mead, Nev., including more than 80 EDCs/PPCPs, to ascertain what effects sample location, sample frequency, and analyte reporting limits have on interpretation of the baseline dataset. The results of this study indicate that for the Lake Mead dataset, the same general conclusions regarding the mean, median, maximum, and minimum concentrations can be drawn from the complete monthly sample dataset as can be drawn from a two-year snapshot and/or even quarterly or bimonthly data alone. This finding points to the possible reduction of sampling campaign frequency and duration for utilities, although this type of analysis needs to be conducted in other watersheds for result portability verification.
Proceedings of the Water Environment Federation, 2010
ABSTRACT Measurable levels of endocrine disrupting compounds (EDCs) and pharmaceutically active c... more ABSTRACT Measurable levels of endocrine disrupting compounds (EDCs) and pharmaceutically active compounds have been detected in septic systems at concentrations well above those shown to cause sexual and developmental abnormalities in vertebrate and invertebrate aquatic species. Specifically, compounds such as steroid hormones and nonionic surfactant metabolites (nonylphenols) are of particular interest because of their widespread use, high level of potency at low concentrations, and ubiquity in wastewaters. Although a few studies indicate that some of these EDCs could be partially removed or transformed during sewage and septic treatment, many of these compounds are still being found in the environment and in drinking water supplies. The results of our research indicate that using combinations of aerobic and anaerobic sand filters or sub-surface flow wetlands in on-site wastewater treatment systems can improve the overall quality of the final effluent and drastically reduces the concentration of steroid estrogens, nonylphenols, and estrogenic activity. Furthermore, the results indicate that the quality of treated effluent impacts the rate of transport and biotransformation of the steroid estrogens through soils after discharge from the on-site wastewater treatment systems. Thus, traditional systems with only a main tank and/or pump tank discharge relatively poor quality water (e.g., high TOC, high ammonia) with high EDC concentrations and estrogenic activity and has the potential to facilitate transport of such compounds to the groundwater environment. This presentation will highlight the key points of our findings among five full scale on-site wastewater treatment and non-potable reuse systems plus the implications of a bench-scale soil transport study.
Journal of Water Supply: Research and Technology—AQUA, 2014
Proceedings of the Water Environment Federation, 2013
The analysis of endocrine disrupting compounds (EDCs) and pharmaceutical and personal care produc... more The analysis of endocrine disrupting compounds (EDCs) and pharmaceutical and personal care products (PPCP), present at trace level in surface waters, is often expensive, time-consuming, and complex. Implementing effective monitoring strategies for these compounds is essential to determine the types of analytes, sampling locations, and sampling frequencies. Multivariate analyses were used to investigate the patterns of EDCs and PPCPs in Lake Mead, Nevada, for these purposes. The results of cluster analysis and principal component analysis to identify the patterns among compounds demonstrated that selected pharmaceuticals tended to be present together with each other, whereas hormones did not show patterns with other compounds. The results of cluster analysis and discriminant analysis to investigate the spatial variation of EDCs and PPCPs eliminated redundant sampling locations, verifying the current selection of sampling locations in Lake Mead. The results of autocorrelation provided optimal sampling frequencies for EDCs and PPCPs, suggesting either monthly or quarterly monitoring of these compounds in Lake Mead. The patterns of the compounds could be site specific; depending on weather and hydrological conditions of the water systems, but this study's approaches will facilitate effective assessment and monitoring of EDCs and PPCPs in surface water.
Proceedings of the Water Environment Federation, 2013
ABSTRACT The additional removal of trace organic contaminants (TOrCs) provided by advanced water ... more ABSTRACT The additional removal of trace organic contaminants (TOrCs) provided by advanced water and wastewater treatment inevitably requires additional financial costs, which must be estimated to support utility planning and compare alternatives. This study presents conceptual-level (Class 4) capital and annual operations and maintenance (O&M) cost curve equations to aid evaluations of advanced treatment trains for water reuse. The cost curve equations are broadly applicable to the water reuse community, particularly those interested in ozone-based treatment trains. Unit processes include microfiltration or ultrafiltration membranes (MF/UF), nanofiltration or reverse osmosis membranes (NF/RO), ozone (with or without hydrogen peroxide, H2O2), ultraviolet (UV) treatment with H2O2 (UV/H2O2), and biological activated carbon (BAC); all cost curves are for a unit process and can be added together to obtain costs for a combined treatment train. The cost curves indicate that at all plant capacities (1 to 500 MGD), membrane treatment (e.g., MF or RO) represents the highest cost unit process, ozone the least, and BAC or UV/H2O2 fall in between. Additionally, the relationship between ozone dose and TOrC removal is discussed with a demonstration of how costs change with increasing ozone dose to achieve desired TOrC destruction.
IDA Journal of Desalination and Water Reuse, 2011
IDA Journal of Desalination and Water Reuse, 2012
The combination of microfiltration (MF) and reverse osmosis (RO) has become an accepted engineeri... more The combination of microfiltration (MF) and reverse osmosis (RO) has become an accepted engineering practice in the treatment of secondary effluent to levels allowable for common and advanced reuse applications. There are several municipalities in the United States and abroad that now utilize this practice on a large scale.
Water Research, 2010
Nonthermal plasma (NTP) Trace organic compound Pharmaceutical Endocrine disrupting compound (EDC)... more Nonthermal plasma (NTP) Trace organic compound Pharmaceutical Endocrine disrupting compound (EDC) a b s t r a c t
Water Research, 2012
Keywords: N-Nitrosodimethylamine (NDMA) the significance of the potential for direct NDMA formati... more Keywords: N-Nitrosodimethylamine (NDMA) the significance of the potential for direct NDMA formation during oxidation in reuse applications. ª (S.A. Snyder).
Journal - American Water Works Association, 2014
ABSTRACT Many water utilities have recently initiated or are considering initiating monitoring pr... more ABSTRACT Many water utilities have recently initiated or are considering initiating monitoring programs to establish baseline contaminant concentrations of endocrine-disrupting compounds (EDCs) and pharmaceuticals/personal care products (PPCPs) in their water supply. Unfortunately, monitoring sites and sampling frequency have often been conducted without regard to end use of the data, loading dynamics, or environmental behavior of trace contaminants. This article provides an a posteriori analysis of more than eight years of monitoring data from Lake Mead, Nev., including more than 80 EDCs/PPCPs, to ascertain what effects sample location, sample frequency, and analyte reporting limits have on interpretation of the baseline dataset. The results of this study indicate that for the Lake Mead dataset, the same general conclusions regarding the mean, median, maximum, and minimum concentrations can be drawn from the complete monthly sample dataset as can be drawn from a two-year snapshot and/or even quarterly or bimonthly data alone. This finding points to the possible reduction of sampling campaign frequency and duration for utilities, although this type of analysis needs to be conducted in other watersheds for result portability verification.