Annual Review of Chemical and Biomolecular Engineering, 2020
Alongside the rising global water demand, continued stress on current water supplies has sparked ... more Alongside the rising global water demand, continued stress on current water supplies has sparked interest in using nontraditional source waters for energy, agriculture, industry, and domestic needs. Membrane technologies have emerged as one of the most promising approaches to achieve water security, but implementation of membrane processes for increasingly complex waters remains a challenge. The technical feasibility of membrane processes replacing conventional treatment of alternative water supplies (e.g., wastewater, seawater, and produced water) is considered in the context of typical and emerging water quality goals. This review considers the effectiveness of current technologies (both conventional and membrane based), as well as the potential for recent advancements in membrane research to achieve these water quality goals. We envision the future of water treatment to integrate advanced membranes (e.g., mixed-matrix membranes, block copolymers) into smart treatment trains that ...
Hurricane Harvey devastated large parts of the US Gulf Coast in 2017, and its floodwaters posed a... more Hurricane Harvey devastated large parts of the US Gulf Coast in 2017, and its floodwaters posed a number of threats to the environment and human health. In particular, an estimated 375 000 Texas residents experienced issues related to the provision of safe drinking water at the peak of the hurricane. In this study, physical, chemical, and biological water quality was monitored in two drinking water systems in Texas following Hurricane Harvey to understand the relationship between water quality parameters and changes in the drinking water microbiota. Results show initial surges in total organic carbon, trihalomethanes, and bacterial concentrations in finished water immediately following Hurricane Harvey. Microbial community analyses highlight the dependence of the distribution system microbiota on distribution system characteristics (i.e. water age), raw water quality, and disinfectant residual, among other factors. While both systems had problems maintaining disinfectant residual in...
The Science of the total environment, Jan 15, 2016
Metal oxide nanoparticles (MONPs) are considered to have the potency to generate reactive oxygen ... more Metal oxide nanoparticles (MONPs) are considered to have the potency to generate reactive oxygen species (ROS), one of the key mechanisms underlying nanotoxicity. However, the nanotoxicology literature demonstrates a lack of consensus on the dominant toxicity mechanism(s) for a particular MONP. Moreover, recent literature has studied the correlation between band structure of pristine MONPs to their ability to introduce ROS and thus has downplayed the ROS-mediated toxicological relevance of a number of such materials. On the other hand, material science can control the band structure of these materials to engineer their electronic and optical properties and thereby is constantly modulating the pristine electronic structure. Since band structure is the fundamental material property that controls ROS-producing ability, band tuning via introduction of dopants and defects needs careful consideration in toxicity assessments. This commentary critically evaluates the existing material scien...
Transportation Research Record: Journal of the Transportation Research Board, 2001
Numerous commercial suppliers are marketing liquid chemical products for stabilizing pavement sub... more Numerous commercial suppliers are marketing liquid chemical products for stabilizing pavement subgrade and base soils. These nontraditional chemical stabilizers may offer viable alternatives for stabilizing sulfate-rich soils where conventional lime or cement treatment can lead to excessive soil expansion. Typically sold as concentrated liquids that are diluted in water before application, these products may be less expensive to use than lime or cement. However, many transportation agencies are hesitant to specify nontraditional liquid stabilizers without better information on the stabilizing mechanisms and documented field experiences. To identify the mechanisms associated with one class of these products, a representative ionic soil stabilizer and a sodium montmorillonite clay were selected for a detailed physical-chemical study. Laboratory testing included chromatography, spectroscopy, X-ray diffraction, electron microscopy, and standard titration analyses. These tests have shown...
Transportation Research Record: Journal of the Transportation Research Board, 2000
A field trial was constructed beneath a secondary state highway in North Yarmouth, Maine, to inve... more A field trial was constructed beneath a secondary state highway in North Yarmouth, Maine, to investigate the water-quality effects of tire shred fills placed above the groundwater table. Samples were collected in three 3-m2 geomembrane-lined basins located beneath the shoulder of the road. Two of the basins are overlaid by 0.61 m of tire shreds with a 75-mm maximum size topped by 0.72 to 1.37 m of granular soil. The third basin serves as a control and is overlaid by only 0.72 m of granular soil. Quarterly samples for inorganic constituents were taken from January 1994 through June 1999. In addition, samples were taken for volatile and semivolatile organic compounds on three dates. Filtered and unfiltered samples were analyzed for the following substances, which have a primary drinking water standard: barium, cadmium, chromium, lead, and selenium. There was no evidence that the presence of tire shreds altered the concentrations of these substances from their naturally occurring backg...
Transportation Research Record: Journal of the Transportation Research Board, 2014
Some findings of the recently completed NCHRP Project 25–32, Measuring and Removing Dissolved Met... more Some findings of the recently completed NCHRP Project 25–32, Measuring and Removing Dissolved Metals from Storm Water in Highly Urbanized Areas, are highlighted. One objective of the project was to assess the potential for adsorption to reduce the concentration of dissolved heavy metals in highway runoff. One of the major difficulties of this type of work is capturing the impacts of background organic matter and other complexing ions on adsorption behavior in multicomponent systems. To address this difficulty, the synthetic stormwater used in this evaluation included natural organic matter (extracted from actual highway runoff) as well as the typical inorganic constituents. A series of column experiments was run with iron oxide, manganese oxide, portland cement concrete, and crab shell waste as adsorbents. Factors that were evaluated included organic matter concentration, competition between metal ion species, pH, ionic strength, and alkalinity. Results of the column experiments ind...
Annual Review of Chemical and Biomolecular Engineering, 2020
Alongside the rising global water demand, continued stress on current water supplies has sparked ... more Alongside the rising global water demand, continued stress on current water supplies has sparked interest in using nontraditional source waters for energy, agriculture, industry, and domestic needs. Membrane technologies have emerged as one of the most promising approaches to achieve water security, but implementation of membrane processes for increasingly complex waters remains a challenge. The technical feasibility of membrane processes replacing conventional treatment of alternative water supplies (e.g., wastewater, seawater, and produced water) is considered in the context of typical and emerging water quality goals. This review considers the effectiveness of current technologies (both conventional and membrane based), as well as the potential for recent advancements in membrane research to achieve these water quality goals. We envision the future of water treatment to integrate advanced membranes (e.g., mixed-matrix membranes, block copolymers) into smart treatment trains that ...
Hurricane Harvey devastated large parts of the US Gulf Coast in 2017, and its floodwaters posed a... more Hurricane Harvey devastated large parts of the US Gulf Coast in 2017, and its floodwaters posed a number of threats to the environment and human health. In particular, an estimated 375 000 Texas residents experienced issues related to the provision of safe drinking water at the peak of the hurricane. In this study, physical, chemical, and biological water quality was monitored in two drinking water systems in Texas following Hurricane Harvey to understand the relationship between water quality parameters and changes in the drinking water microbiota. Results show initial surges in total organic carbon, trihalomethanes, and bacterial concentrations in finished water immediately following Hurricane Harvey. Microbial community analyses highlight the dependence of the distribution system microbiota on distribution system characteristics (i.e. water age), raw water quality, and disinfectant residual, among other factors. While both systems had problems maintaining disinfectant residual in...
The Science of the total environment, Jan 15, 2016
Metal oxide nanoparticles (MONPs) are considered to have the potency to generate reactive oxygen ... more Metal oxide nanoparticles (MONPs) are considered to have the potency to generate reactive oxygen species (ROS), one of the key mechanisms underlying nanotoxicity. However, the nanotoxicology literature demonstrates a lack of consensus on the dominant toxicity mechanism(s) for a particular MONP. Moreover, recent literature has studied the correlation between band structure of pristine MONPs to their ability to introduce ROS and thus has downplayed the ROS-mediated toxicological relevance of a number of such materials. On the other hand, material science can control the band structure of these materials to engineer their electronic and optical properties and thereby is constantly modulating the pristine electronic structure. Since band structure is the fundamental material property that controls ROS-producing ability, band tuning via introduction of dopants and defects needs careful consideration in toxicity assessments. This commentary critically evaluates the existing material scien...
Transportation Research Record: Journal of the Transportation Research Board, 2001
Numerous commercial suppliers are marketing liquid chemical products for stabilizing pavement sub... more Numerous commercial suppliers are marketing liquid chemical products for stabilizing pavement subgrade and base soils. These nontraditional chemical stabilizers may offer viable alternatives for stabilizing sulfate-rich soils where conventional lime or cement treatment can lead to excessive soil expansion. Typically sold as concentrated liquids that are diluted in water before application, these products may be less expensive to use than lime or cement. However, many transportation agencies are hesitant to specify nontraditional liquid stabilizers without better information on the stabilizing mechanisms and documented field experiences. To identify the mechanisms associated with one class of these products, a representative ionic soil stabilizer and a sodium montmorillonite clay were selected for a detailed physical-chemical study. Laboratory testing included chromatography, spectroscopy, X-ray diffraction, electron microscopy, and standard titration analyses. These tests have shown...
Transportation Research Record: Journal of the Transportation Research Board, 2000
A field trial was constructed beneath a secondary state highway in North Yarmouth, Maine, to inve... more A field trial was constructed beneath a secondary state highway in North Yarmouth, Maine, to investigate the water-quality effects of tire shred fills placed above the groundwater table. Samples were collected in three 3-m2 geomembrane-lined basins located beneath the shoulder of the road. Two of the basins are overlaid by 0.61 m of tire shreds with a 75-mm maximum size topped by 0.72 to 1.37 m of granular soil. The third basin serves as a control and is overlaid by only 0.72 m of granular soil. Quarterly samples for inorganic constituents were taken from January 1994 through June 1999. In addition, samples were taken for volatile and semivolatile organic compounds on three dates. Filtered and unfiltered samples were analyzed for the following substances, which have a primary drinking water standard: barium, cadmium, chromium, lead, and selenium. There was no evidence that the presence of tire shreds altered the concentrations of these substances from their naturally occurring backg...
Transportation Research Record: Journal of the Transportation Research Board, 2014
Some findings of the recently completed NCHRP Project 25–32, Measuring and Removing Dissolved Met... more Some findings of the recently completed NCHRP Project 25–32, Measuring and Removing Dissolved Metals from Storm Water in Highly Urbanized Areas, are highlighted. One objective of the project was to assess the potential for adsorption to reduce the concentration of dissolved heavy metals in highway runoff. One of the major difficulties of this type of work is capturing the impacts of background organic matter and other complexing ions on adsorption behavior in multicomponent systems. To address this difficulty, the synthetic stormwater used in this evaluation included natural organic matter (extracted from actual highway runoff) as well as the typical inorganic constituents. A series of column experiments was run with iron oxide, manganese oxide, portland cement concrete, and crab shell waste as adsorbents. Factors that were evaluated included organic matter concentration, competition between metal ion species, pH, ionic strength, and alkalinity. Results of the column experiments ind...
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Papers by Lynn Katz