Creat membership Creat membership
Sign in

Forgot password?

Confirm
  • Forgot password?
    Sign Up
  • Confirm
    Sign In
home > search

Now showing items 1 - 16 of 1226

  • Evaluation of Interventions to Reduce Firefighter Exposures

    Burgess, Jefferey L.   Hoppe-Jones, Christiane   Griffin, Stephanie C.   Zhou, Jin J.   Gulotta, John J.   Wallentine, Darin D.   Moore, Paul K.   Valliere, Eric A.   Weller, Sasha R.   Beitel, Shawn C.   Flahr, Leanne M.   Littau, Sally R.   Dearmon-Moore, Devi   Zhai, Jing   Jung, Alesia M.   Garavito, Fernanda   Snyder, Shane A.  

    Download Collect
  • Pretreatment for water reuse using fluidized bed crystallization

    AzadiAghdam, Mojtaba   Park, Minkyu   Lopez-Prieto, Israel J.   Achilli, Andrea   Snyder, Shane A.   Farrell, James  

    Download Collect
  • A review of polymeric membranes and processes for potable water reuse

    Warsinger, David M.   Chakraborty, Sudip   Tow, Emily W.   Plumlee, Megan H.   Bellona, Christopher   Loutatidou, Sawina   Karimi, Leila   Mikelonis, Anne M.   Achilli, Andrea   Ghassemi, Abbas   Padhye, Lokesh P.   Snyder, Shane A.   Curcio, Stefano   Vecitis, Chad D.   Arafat, Hassan A.   Lienhard, John H., V  

    Conventional water resources in many regions are insufficient to meet the water needs of growing populations, thus reuse is gaining acceptance as a method of water supply augmentation. Recent advancements in membrane technology have allowed for the reclamation of municipal wastewater for the production of drinking water, i.e., potable reuse. Although public perception can be a challenge, potable reuse is often the least energy-intensive method of providing additional drinking water to water stressed regions. A variety of membranes have been developed that can remove water contaminants ranging from particles and pathogens to dissolved organic compounds and salts. Typically, potable reuse treatment plants use polymeric membranes for microfiltration or ultrafiltration in conjunction with reverse osmosis and, in some cases, nanofiltration. Membrane properties, including pore size, wettability, surface charge, roughness, thermal resistance, chemical stability, permeability, thickness and mechanical strength, vary between membranes and applications. Advancements in membrane technology including new membrane materials, coatings, and manufacturing methods, as well as emerging membrane processes such as membrane bioreactors, electrodialysis, and forward osmosis have been developed to improve selectivity, energy consumption, fouling resistance, and/or capital cost. The purpose of this review is to provide a comprehensive summary of the role of polymeric membranes and process components in the treatment of wastewater to potable water quality and to highlight recent advancements and needs in separation processes. Beyond membranes themselves, this review covers the background and history of potable reuse, and commonly used potable reuse process chains, pretreatment steps, and advanced oxidation processes. Key trends in membrane technology include novel configurations, materials, and fouling prevention techniques. Challenges still facing membrane-based potable reuse applications, including chemical and biological contaminant removal, membrane fouling, and public perception, are highlighted as areas in need of further research and development. (C) 2018 Elsevier B.V. All rights reserved.
    Download Collect
  • A novel sequential process for remediating rare-earth wastewater

    Cui, Mingcan   Jang, Min   Kang, Kyounglim   Kim, Dukmin   Snyder, Shane A.   Khim, Jeehyeong  

    A novel and economic sequential process consisting of precipitation, adsorption, and oxidation was developed to remediate actual rare-earth (RE) wastewater containing various toxic pollutants, including radioactive species. In the precipitation step, porous air stones (PAS) containing waste oyster shell (WOS), PAS(WOS), was prepared and used to precipitate most heavy metals with >97% removal efficiencies. The SEM-EDS analysis revealed that PAS plays a key role in preventing the surface coating of precipitants on the surface of WOS and in releasing the dissolved species of WOS successively. For the adsorption step, a polyurethane (PU) impregnated by coal mine drainage sludge (CMDS), PUCMDS, was synthesized and applied to deplete fluoride (F), arsenic (As), uranium (U), and thorium (Th) that remained after precipitation. The continuous-mode sequential process using PAS(WOS), PUCMDS, and ozone (O-3) had 99.9-100% removal efficiencies of heavy metals, 99.3-99.9% of F and As, 95.8-99.4% of U and Th, and 92.4% of CODCr for 100 days. The sequential process can treat RE wastewater economically and effectively without stirred-tank reactors, pH controller, continuous injection of chemicals, and significant sludge generation, as well as the quality of the outlet met the EPA recommended limits. (C) 2015 Elsevier Ltd. All rights reserved.
    Download Collect
  • Assessment of the toxicity of firefighter exposures using the PAH CALUX bioassay

    Beitel, Shawn C.   Flahr, Leanne M.   Hoppe-Jones, Christiane   Burgess, Jefferey L.   Littau, Sally R.   Gulotta, John   Moore, Paul   Wallentine, Darin   Snyder, Shane A.  

    Download Collect
  • Bioanalytical tools: half a century of application for potable reuse

    Snyder, Shane A.  

    In vitro bioassays, more recently referred to as "bioanalytical tools" in an attempt to emphasize their analytical purpose rather than the uncertain relation to adverse health outcomes, are often thought of as novel tools by water stakeholders. They have, however, been used for over half a century in assessment of recycled water quality. Today, millions of chemicals and formulations are available for commercial use and most have a high propensity to enter sewage collection systems. However, traditional health risk assessment methods involving animal testing at high doses and extrapolation to environmental relevant levels are vastly overwhelmed in capacity by the innumerable chemicals and transformation products potentially present in waters. Beyond the sheer number of chemicals, the interactions of these chemicals as complex mixtures is largely unaddressed in traditional regulatory schemes. Moreover, non-human animal models are often misleading due to differences in metabolism and associated pharmacokinetics. Thus, water professionals continue to struggle with ever increasing numbers of chemicals detected at trace levels in water and the potential interactions of these chemicals during mixture exposures. Bioanalytical tools offer a path forward towards more comprehensive chemical evaluations of water, which can provide greater public confidence in the ability of potable reuse schemes to produce clean and safe drinking water.
    Download Collect
  • Emerging chemical contaminants: Looking for greater harmony

    Snyder, Shane A.  

    Download Collect
  • Metformin Scavenges Methylglyoxal To Form a Novel Imidazolinone Metabolite in Humans

    Kinsky, Owen R.   Hargraves, Tiffanie L.   Anumol, Tarun   Jacobsen, Neil E.   Dai, Jixun   Snyder, Shane A.   Monks, Terrence J.   Lau, Serrine S.  

    Methylglyoxal (MG) is a highly reactive dicarbonyl compound involved in the formation of advanced glycation endproducts (AGE). Levels of MG are elevated in patients with type-2 diabetes mellitus (T2DM), and AGE have been implicated in the progression of diabetic complications. The antihyperglycemic drug metformin (MF) has been suggested to be a scavenger of MG. The present work examined and characterized unequivocally the resulting scavenged product from the metformin MG reaction. The primary product was characterized by H-1, C-13, 2D-HSQC, and HMBC NMR and tandem mass spectrometry. X-ray diffraction analysis determined the structure of the metformin and MG-derived imidazolinone compound as (E)-1,1-dimethyl-2-(5methyl-4-oxo-4,5-dihydro-1H-imidazol-2-yl)guanidine (IMZ). A LC-MS/MS multiple reaction monitoring method was developed to detect and quantify the presence of IMZ in metformin-treated T2DM patients. Urine from >90 MF-treated T2DM patients was analyzed, with increased levels of MF directly correlating with elevations in IMZ. Urinary MF was detected in the range of 0.17 mu M to 23.0 mM, and simultaneous measurement of IMZ concentrations were in the range of 18.8 nM to 4.3 mu M. Since plasma concentrations of MG range from 40 nM to 4.5 mu M, the level of IMZ production may be of therapeutic significance. Thus, in addition to lowering hepatic gluconeogenesis, metformin also scavenges the highly reactive MG in vivo, thereby reducing potentially detrimental MG protein adducts, with subsequent reductions in diabetic complications.
    Download Collect
  • Transformation of 1H-Benzotriazole by Ozone in Aqueous Solution

    Mawhinney, Douglas B.   Vanderford, Brett J.   Snyder, Shane A.  

    Recent studies have shown that 1H-benzotriazole is a widespread contaminant of wastewater and surface water. Although disinfection by ozone has been shown to efficiently remove this compound, the transformation products have not been identified. To that end, the reaction of ozone with 1H-benzotriazole in aqueous solution has been studied in real time employing quadrupole time-of-flight mass spectrometry (QTOF MS) and negative electrospray ionization. The transformation products have been identified by calculating their empirical formulas using accurate mass measurements, and further confirmed by performing the reaction with stable isotope-labeled 1H-benzotriazole and measuring product ion spectra. Stable reaction products were distinguished from transient species by plotting their extracted mass profiles. The products that resulted from ozone and hydroxyl radicals in the reaction were qualitatively identified by modifying the conditions to either promote the formation of hydroxyl radicals, or to scavenge them. Based on experimental evidence, a mechanism for the direct reaction between ozone and 1H-benzotriazole is proposed that results in the formation of 1H-1,2,3-triazole-4,5-dicarbaldehyde, which has an empirical formula of C4H3O2N3. Lastly, it was confirmed that the same transformation products formed in surface water and tertiary-treated wastewater, although they were observed to degrade at higher ozone doses.
    Download Collect
  • Artificial Sweetener Sucralose in U.S. Drinking Water Systems

    Young, Robert B.   Vanderford, Brett J.   Borch, Thomas   Snyder, Shane A.  

    The artificial sweetener sucralose has recently been shown to be a widespread of contaminant of wastewater, surface water, and groundwater. In order to understand its occurrence in drinking water systems, water samples from 19 United States (U.S.) drinking water treatment plants (DWTPs) serving more than 28 million people were analyzed for sucralose using liquid chromatography tandem mass spectrometry (LC-MS/MS). Sucralose was found to be present in source water of 15 out of 19 DWTPs (47-2900 ng/L), finished water of 13 out of 17 DWTPs (49-2400 ng/L) and distribution system water of 8 out Of the 12 DWTPs (48-2400 ng/L) tested. Sucralose was only found to be present in source waters with known wastewater influence and/or recreational usage, and displayed low removal (12% average) in the DWTPs where finished water was sampled. Further, in the subset of DWTPs with distribution system water sampled, the compound was found to persist regardless of the presence of residual chlorine or chloramines. In order to understand intra-DWTP consistency, sucralose was monitored at one drinking water treatment plant over an 11 month period from March 2010 through January 2011, and averaged 440 ng/L in the source water and 350 ng/L in the finished water. The results of this study confirm that sucralose will function well as an indicator compound for anthropogenic influence on source, finished drinking and distribution system (i.e., tap) water, as well as an indicator compound for the presence of other recalcitrant compounds in finished drinking water in the U.S.
    Download Collect
  • A review of extraction methods for the analysis of pharmaceuticals in environmental waters

    Daniels, Kevin D.   Park, Minkyu   Huang, Zhenzhen   Jia, Ai   Flores, Guillermo S.   Lee, Hian Kee   Snyder, Shane A.  

    Download Collect
  • Impact of Drought on Wastewater Contaminants in an Urban Water Supply

    Benotti, Mark J.   Stanford, Benjamin D.   Snyder, Shane A.  

    Download Collect
  • Endocrine disruptors and pharmaceuticals: implications for water sustainability

    Snyder, Shane A.   Benotti, Mark J.  

    The presence of pharmaceuticals and endocrine disrupting compounds (EDCs) in the environment raises many questions about risk to the environment and risk to human health. Researchers have attributed adverse ecological effect effects to the presence of these compounds, particularly EDCs, though there is no consensus on what risk, if any, these compounds pose to human health. The scientific community is in the process of developing a better understanding of the occurrence, fate, and transport of pharmaceuticals and EDCs in the environment, including a better characterization of human exposure via drinking water. This paper provides a brief review of pharmaceuticals and EDCs in drinking water, as well as uses examples from Lake Mead, Nevada, USA, to highlight the issues associated with their fate and transport. Lastly, the effects of natural or anthropogenically driven processes, like natural seasonal flow or climate-change/prolonged drought are discussed as they are factors which can drastically alter environmental concentrations of these compounds. Without question, the propensity for the contamination of fresh water will rise as (1) human population continues to grow or (2) patterns of natural surface water slow and wastewater becomes a larger fraction of flow further highlighting the need for a more comprehensive understanding of their environmental behavior.
    Download Collect
  • Removal of emerging contaminants of concern by alternative adsorbents

    Rossner, Alfred   Snyder, Shane A.   Knappe, Detlef R. U.  

    The effective removal of emerging contaminants of concern (ECCs) such as endocrine-disrupting chemicals, pharmaceutically active compounds, personal care products, and flame retardants is a desirable water treatment goal. In this study, one activated carbon, one carbonaceous resin, and two high-silica zeolites were studied to evaluate their effectiveness for the removal of an ECC mixture from lake water. Adsorption isotherm experiments were performed with a mixture of 28 ECCs at environmentally relevant concentrations (similar to 200-900 ng/L). Among the tested adsorbents, activated carbon was the most effective, and activated carbon doses typically used for taste and odor control in drinking water (<10 mg/L) were sufficient to achieve a 2-log removal for most of the tested ECCs. The carbonaceous resin was less effective than the activated carbon because this adsorbent had a smaller volume of pores in the size range required for the adsorption of many ECCs (similar to 6-9 angstrom). For the removal of ECC mixture constituents, zeolites were less effective than the carbonaceous adsorbents. Because zeolites contain pores of uniform size and shape, a few of the tested ECCs with matching pore size/shape requirements were well removed, but the adsorptive removal of others was negligible, even at zeolite doses of 100 mg/L. The results of this study demonstrate that effective adsorbents for the removal of a broad spectrum of ECCs from water should exhibit heterogeneity in pore size and shape and a large pore volume in the 6-9 angstrom size range. (C) 2009 Elsevier Ltd. All rights reserved.
    Download Collect
  • Statistical profiling for identifying transformation products in an engineered treatment process

    Park, Minkyu   Snyder, Shane A.  

    Download Collect
  • Comprehensive Handbook of Iodine || Iodate and Perchlorate in Bottled Water

    Snyder, Shane A.  

    Download Collect
1 2 3 4 5 6 7 8 9 10

Contact

If you have any feedback, Please follow the official account to submit feedback.

Turn on your phone and scan

Submit Feedback