Water Disinfection

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Desheng Kong - One of the best experts on this subject based on the ideXlab platform.

Martin Jekel - One of the best experts on this subject based on the ideXlab platform.

  • Ultraviolet Light-Emitting Diodes for Water Disinfection
    III-Nitride Ultraviolet Emitters, 2016
    Co-Authors: Marlene A. Lange, Tim Kolbe, Martin Jekel
    Abstract:

    This chapter presents basic principles of Water Disinfection using UV light. It provides a comparison of conventional UV light sources and UV LEDs. Additionally, based on a detailed case study, the potential of UV LEDs for Water Disinfection systems is discussed. This study presents results of static and flow-through tests conducted with UV LEDs of different emission wavelengths.

  • application of gan based ultraviolet c light emitting diodes uv leds for Water Disinfection
    Water Research, 2011
    Co-Authors: M.a. Würtele, Tim Kolbe, M. Lipsz, A. Külberg, Markus Weyers, Michael Kneissl, Martin Jekel
    Abstract:

    Abstract GaN-based ultraviolet-C (UV–C) light emitting diodes (LEDs) are of great interest for Water Disinfection. They offer significant advantages compared to conventional mercury lamps due to their compact form factor, low power requirements, high efficiency, non-toxicity, and overall robustness. However, despite the significant progress in the performance of semiconductor based UV LEDs that has been achieved in recent years, these devices still suffer from low emission power and relatively short lifetimes. Even the best UV LEDs exhibit external quantum efficiencies of only 1–2%. The objective of this study was to investigate the suitability of GaN-based UV LEDs for Water Disinfection. The investigation included the evaluation of the performance characteristics of UV LEDs at different operating conditions as well as the design of a UV LED module in view of the requirements for Water treatment applications. Bioanalytical testing was conducted using Bacillus subtilis spores as test organism and UV LED modules with emission wavelengths of 269 nm and 282 nm. The results demonstrate the functionality of the developed UV LED Disinfection modules. GaN-based UV LEDs effectively inactivated B. subtilis spores during static and flow-through tests applying varying Water qualities. The 269 nm LEDs reached a higher level of inactivation than the 282 nm LEDs for the same applied fluence. The lower inactivation achieved by the 282 nm LEDs was compensated by their higher photon flux. First flow-through tests indicate a linear correlation between inactivation and fluence, demonstrating a well designed flow-through reactor. With improved light output and reduced costs, GaN-based UV LEDs can provide a promising alternative for decentralised and mobile Water Disinfection systems.

Shuang Wang - One of the best experts on this subject based on the ideXlab platform.

Elizabeth D. Wagner - One of the best experts on this subject based on the ideXlab platform.

  • Haloacetic Acid Water Disinfection Byproducts Affect Pyruvate Dehydrogenase Activity and Disrupt Cellular Metabolism
    Environmental Science & Technology, 2018
    Co-Authors: Azra Dad, Clara H. Jeong, Elizabeth D. Wagner
    Abstract:

    The Disinfection of drinking Water has been a major public health achievement. However, haloacetic acids (HAAs), generated as by-products of Water Disinfection, are cytotoxic, genotoxic, mutagenic, carcinogenic and teratogenic. Previous studies of monoHAA-induced genotoxicity and cell stress demonstrated that the toxicity was due to inhibition of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) leading to disruption of cellular metabolism and energy homeostasis. DiHAAs and triHAAs are also produced during Water Disinfection, and whether they share mechanisms of action with monoHAAs is unknown. In this study, we evaluated the effects of mono-, di-, and tri-HAAs on cellular GAPDH enzyme kinetics, cellular ATP levels, and pyruvate dehydrogenase complex (PDC) activity. Here, treatments conducted in Chinese hamster ovary (CHO) cells revealed differences among mono-, di-, and triHAA in their molecular targets. The monoHAAs, iodoacedic acid and bromoacetic acid, were the strongest inhibitors of GAPDH and greatly...

  • Haloacetic Acid Water Disinfection Byproducts Affect Pyruvate Dehydrogenase Activity and Disrupt Cellular Metabolism
    2017
    Co-Authors: Azra Dad, Clara H. Jeong, Elizabeth D. Wagner, Michael J. Plewa
    Abstract:

    The Disinfection of drinking Water has been a major public health achievement. However, haloacetic acids (HAAs), generated as byproducts of Water Disinfection, are cytotoxic, genotoxic, mutagenic, carcinogenic, and teratogenic. Previous studies of monoHAA-induced genotoxicity and cell stress demonstrated that the toxicity was due to inhibition of glyceraldehyde-3-phosphate dehydrogenase (GAPDH), leading to disruption of cellular metabolism and energy homeostasis. DiHAAs and triHAAs are also produced during Water Disinfection, and whether they share mechanisms of action with monoHAAs is unknown. In this study, we evaluated the effects of mono-, di-, and tri-HAAs on cellular GAPDH enzyme kinetics, cellular ATP levels, and pyruvate dehydrogenase complex (PDC) activity. Here, treatments conducted in Chinese hamster ovary (CHO) cells revealed differences among mono-, di-, and triHAAs in their molecular targets. The monoHAAs, iodoacetic acid and bromoacetic acid, were the strongest inhibitors of GAPDH and greatly reduced cellular ATP levels. Chloroacetic acid, diHAAs, and triHAAs were weaker inhibitors of GAPDH and some increased the levels of cellular ATP. HAAs also affected PDC activity, with most HAAs activating PDC. The primary finding of this work is that mono- versus multi-HAAs address different molecular targets, and the results are generally consistent with a model in which monoHAAs activate the PDC through GAPDH inhibition-mediated disruption in cellular metabolites, including altering ATP-to-ADP and NADH-to-NAD ratios. The monoHAA-mediated reduction in cellular metabolites results in accelerated PDC activity by way of metabolite-ratio-dependent PDC regulation. DiHAAs and triHAAs are weaker inhibitors of GAPDH, but many also increase cellular ATP levels, and we suggest that they increase PDC activity by inhibiting pyruvate dehydrogenase kinase

  • Monohaloacetic acid drinking Water Disinfection by-products inhibit follicle growth and steroidogenesis in mouse ovarian antral follicles in vitro.
    Reproductive Toxicology, 2016
    Co-Authors: Clara H. Jeong, Tyler Dettro, Liying Gao, Elizabeth D. Wagner, William A. Ricke, Jodi Anne Flaws
    Abstract:

    Abstract Water Disinfection greatly reduced the incidence of Waterborne diseases, but the reaction between disinfectants and natural organic matter in Water leads to the formation of drinking Water Disinfection by-products (DBPs). DBPs have been shown to be toxic, but their effects on the ovary are not well defined. This study tested the hypothesis that monohalogenated DBPs (chloroacetic acid, CAA; bromoacetic acid, BAA; iodoacetic acid, IAA) inhibit antral follicle growth and steroidogenesis in mouse ovarian follicles. Antral follicles were isolated and cultured with either vehicle or DBPs (0.25–1.00 mM of CAA; 2–15 μM of BAA or IAA) for 48 and 96 h. Follicle growth was measured every 24 h and the media were analyzed for estradiol levels at 96 h. Exposure to DBPs significantly inhibited antral follicle growth and reduced estradiol levels compared to controls. These data demonstrate that DBP exposure caused ovarian toxicity in vitro .

  • Biological mechanism for the toxicity of haloacetic acid drinking Water Disinfection byproducts.
    Environmental Science & Technology, 2011
    Co-Authors: Justin A. Pals, Justin K. Ang, Elizabeth D. Wagner
    Abstract:

    The halogenated acetic acids are a major class of drinking Water Disinfection byproducts (DBPs) with five haloacetic acids regulated by the U.S. EPA. These agents are cytotoxic, genotoxic, mutagenic, and teratogenic. The decreasing toxicity rank order of the monohalogenated acetic acids (monoHAAs) is iodo- > bromo- ≫ chloroacetic acid. We present data that the monoHAAs inhibit glyceraldehyde-3-phosphate dehydrogenase (GAPDH) activity in a concentration-dependent manner with the same rank order as above. The rate of inhibition of GAPDH and the toxic potency of the monoHAAs are highly correlated with their alkylating potential and the propensity of the halogen leaving group. This strong association between GAPDH inhibition and the monoHAA toxic potency supports a comprehensive mechanism for the adverse biological effects by this widely occurring class of regulated DBPs.

  • Modulation of the Cytotoxicity and Genotoxicity of the Drinking Water Disinfection Byproduct Iodoacetic Acid by Suppressors of Oxidative Stress
    Environmental science & technology, 2006
    Co-Authors: Eduardo Cemeli, Elizabeth D. Wagner, Diana Anderson, Susan D. Richardson
    Abstract:

    Drinking Water Disinfection byproducts (DBPs) are generated by the chemical Disinfection of Water and may pose a hazard to the public health. Previously we demonstrated that iodoacetic acid was the...

Francis Hassard - One of the best experts on this subject based on the ideXlab platform.

  • Application of ultraviolet light-emitting diodes (UV-LED) to full-scale drinking-Water Disinfection
    Water, 2019
    Co-Authors: Peter Jarvis, Olivier Autin, Emma H Goslan, Francis Hassard
    Abstract:

    Ultraviolet light-emitting diodes (UV-LEDs) have recently emerged as a viable technology for Water Disinfection. However, the performance of the technology in full-scale drinking-Water treatment systems remains poorly characterised. Furthermore, current UV Disinfection standards and protocols have been developed specifically for conventional mercury UV systems and so do not necessarily provide an accurate indication of UV-LED Disinfection performance. Hence, this study aimed to test the hypothesis that a full-scale UV-LED reactor can match the Cryptosporidium inactivation efficiency of conventional mercury UV reactors. Male-specific bacteriophage (MS2) was used as the Cryptosporidium spp. surrogate microorganism. The time-based inactivation efficiency of the full-scale reactor was firstly compared to that of a bench-scale (batch-type) UV-LED reactor. This was then related to mercury UV reactors by comparing the fluence-based efficiency of the bench-scale reactor to the USEPA 90% prediction interval range of expected MS2 inactivation using mercury UV lamps. The results showed that the full-scale UV-LED reactor was at least as effective as conventional mercury UV reactors at the Water-quality and drive-current conditions considered. Nevertheless, comparisons between the bench- and full-scale UV-LED reactors indicated that improvements in the hydraulic flow profile and power output of the full-scale reactor could help to further improve the efficiency of UV-LED reactors for municipal drinking Water Disinfection. This represents the world’s first full-scale UV-LED reactor that can be applied at municipal Water treatment works for Disinfection of pathogenic microorganisms from drinking Water.

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