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Sample records for disinfection by-product analysis

  1. Risk analysis of drinking water microbial contamination versus disinfection by-products (DBPs)

    International Nuclear Information System (INIS)

    Ashbolt, Nicholas John

    2004-01-01

    Managing the provision of safe drinking water has a renewed focus in light of the new World Health Organization (WHO) water safety plans. Risk analysis is a necessary component to assist in selecting priority hazards and identifying hazardous scenarios, be they qualitative to quantitative assessments. For any approach, acute diarrhoeal pathogens are often the higher risk issue for municipal water supplies, no matter how health burden is assessed. Furthermore, potential sequellae (myocarditis, diabetes, reactive arthritis and cancers) only further increase the potential health burden of pathogens; despite the enormous uncertainties in determining pathogen exposures and chemical dose-responses within respective microbial and chemical analyses. These interpretations are currently being improved by Bayesian and bootstrapping approaches to estimate parameters for stochastic assessments. A case example, covering the health benefits of ozonation for Cryptosporidium inactivation versus potential cancers from bromate exposures, illustrated the higher risks from a pathogen than one of the most likely disinfection by-products (DBPs). Such analyses help justify the industries long-held view of the benefits of multiple barriers to hazards and that microbial contamination of water supplies pose a clear public health risk when treatment is inadequate. Therefore, efforts to reduce potential health risks from DBP must not compromise pathogen control, despite socio-political issues

  2. Water disinfection agents and disinfection by-products

    Science.gov (United States)

    Ilavský, J.; Barloková, D.; Kapusta, O.; Kunštek, M.

    2017-10-01

    The aim of this work is to describe factors of water quality change in the distribution network and legislative requirements in Slovakia for disinfectants and disinfection byproducts (DBPs). In the experimental part, the time dependence of the application of the chlorine dioxide and sodium hypochlorite on the formation of some by-products of disinfection for drinking water from WTP Hriňová is studied. We monitored trihalomethanes, free chlorine, chlorine dioxide and chlorites.

  3. Precursors of nitrogenous disinfection by-products in drinking water--A critical review and analysis

    Energy Technology Data Exchange (ETDEWEB)

    Bond, Tom [Department of Civil and Environmental Engineering, Imperial College London, London SW7 2AZ (United Kingdom); Templeton, Michael R.; Graham, Nigel [Department of Civil and Environmental Engineering, Imperial College London, London SW7 2AZ (United Kingdom)

    2012-10-15

    Highlights: Black-Right-Pointing-Pointer The proportion of N-DBP formation attributable to specific precursors was calculated. Black-Right-Pointing-Pointer Precursor concentrations are typically insufficient to account for observed N-DBP formation, except CNX and NDMA. Black-Right-Pointing-Pointer Amino acid precursors are easier to remove during water treatment than suggested by laboratory studies. - Abstract: In recent years research into the formation of nitrogenous disinfection by-products (N-DBPs) in drinking water - including N-nitrosodimethylamine (NDMA), the haloacetonitriles (HANs), haloacetamides (HAcAms), cyanogen halides (CNX) and halonitromethanes (HNMs) - has proliferated. This is partly due to their high reported toxicity of N-DBPs. In this review paper information about the formation yields of N-DBPs from model precursors, and about environmental precursor occurrence, has been employed to assess the amount of N-DBP formation that is attributable to known precursors. It was calculated that for HANs and HAcAms, the concentrations of known precursors - mainly free amino acids are insufficient to account for the observed concentrations of these N-DBP groups. However, at least in some waters, a significant proportion of CNX and NDMA formation can be explained by known precursors. Identified N-DBP precursors tend to be of low molecular weight and low electrostatic charge relative to bulk natural organic matter (NOM). This makes them recalcitrant to removal by water treatment processes, notably coagulation, as confirmed by a number of bench-scale studies. However, amino acids have been found to be easier to remove during water treatment than would be suggested by the known molecular properties of the individual free amino acids.

  4. Analysis, Occurrence and Toxicity of Haloacetaldehydes in Drinking Waters: Iodacetaldehyde as an Emerging Disinfection ByProduct.

    Science.gov (United States)

    Chlorinated and brominated haloacetaldehydes (HALs) are consideredthe 3rd largest class of disinfection by-products (DBPs) by weight. The iodinatedHAL, iodoacetaldehyde, has been recently reported as an emerging DBP infinished drinking waters. Overall, iodinated DBPs, e.g., iodoa...

  5. Studies on Disinfection By-Products and Drinking Water

    Science.gov (United States)

    Rostad, Colleen E.

    2007-01-01

    Drinking water is disinfected with chemicals to remove pathogens, such as Giardia and Cryptosproridium, and prevent waterborne diseases such as cholera and typhoid. During disinfection, by-products are formed at trace concentrations. Because some of these by-products are suspected carcinogens, drinking water utilities must maintain the effectiveness of the disinfection process while minimizing the formation of by-products.

  6. Genotoxicity analysis of two halonitromethanes, a novel group of disinfection by-products (DBPs), in human cells treated in vitro

    International Nuclear Information System (INIS)

    Liviac, Danae; Creus, Amadeu; Marcos, Ricard

    2009-01-01

    Halonitromethanes (HNMs) constitute an emerging class of disinfection by-products (DBPs) produced when chlorine and/or ozone are used for water treatment. The HNMs are structurally similar to halomethanes, but have a nitro-group in place of hydrogen bonded to the central carbon atom. Since little information exists on the genotoxic potential of HNMs, a study has been carried out with two HNM compounds, namely trichloronitromethane (TCNM) and bromonitromethane (BNM) by using human cells. Primary damage induction has been measured with the Comet assay, which is used to determine both the repair kinetics of the induced damage and the proportion of induced oxidative damage. In addition, the fixed DNA damage has been evaluated by using the micronucleus (MN) assay. The results obtained indicate that both compounds are genotoxic, inducing high levels of DNA breaks in the Comet assay, and that this DNA damage repairs well over time. In addition, oxidized bases constitute a high proportion of DNA-induced damage (50-75%). Contrarily, no positive effects were observed in the frequency of micronucleus, which measures both clastogenic and aneugenic effects, neither using TK6 cells nor peripheral blood lymphocytes. This lack of fixed genetic damage would minimize the potential mutagenic risk associated with HNMs exposure

  7. Precursors of nitrogenous disinfection by-products in drinking water––A critical review and analysis

    International Nuclear Information System (INIS)

    Bond, Tom; Templeton, Michael R.; Graham, Nigel

    2012-01-01

    Highlights: ► The proportion of N-DBP formation attributable to specific precursors was calculated. ► Precursor concentrations are typically insufficient to account for observed N-DBP formation, except CNX and NDMA. ► Amino acid precursors are easier to remove during water treatment than suggested by laboratory studies. - Abstract: In recent years research into the formation of nitrogenous disinfection by-products (N-DBPs) in drinking water – including N-nitrosodimethylamine (NDMA), the haloacetonitriles (HANs), haloacetamides (HAcAms), cyanogen halides (CNX) and halonitromethanes (HNMs) – has proliferated. This is partly due to their high reported toxicity of N-DBPs. In this review paper information about the formation yields of N-DBPs from model precursors, and about environmental precursor occurrence, has been employed to assess the amount of N-DBP formation that is attributable to known precursors. It was calculated that for HANs and HAcAms, the concentrations of known precursors – mainly free amino acids are insufficient to account for the observed concentrations of these N-DBP groups. However, at least in some waters, a significant proportion of CNX and NDMA formation can be explained by known precursors. Identified N-DBP precursors tend to be of low molecular weight and low electrostatic charge relative to bulk natural organic matter (NOM). This makes them recalcitrant to removal by water treatment processes, notably coagulation, as confirmed by a number of bench-scale studies. However, amino acids have been found to be easier to remove during water treatment than would be suggested by the known molecular properties of the individual free amino acids.

  8. Chlorine dioxine DBPs (disinfection by-products in drinking water

    Directory of Open Access Journals (Sweden)

    C. Lasagna

    2013-01-01

    Full Text Available Since the 1970s it has been well known that, though water for human consumption is generally disinfected before being distributed along the network, the use of chemicals results in the formation of many different Disinfection By-Products (DBPs. In the case of chlorine dioxide, the most important and represented DBPs are chlorite and chlorate: after an introduction concerning the current Italian regulation on this subject, in the experimental part the results of a 7-year minitoring campaign, concerning water of different origin collected from taps in various Italian regions, are shown. The analytical technique used for the determination of chlorite and chlorate was Ion Chromatography. The result obtained are finally discussed.

  9. Integrated Disinfection By-Products Mixtures Research: Concentration by Reverse Osmosis Membrane Techniques of Disinfection By-Products from Water Disinfected by Chlorination and Ozonation/Postchlorination

    Science.gov (United States)

    To conduct the health-effect studies described in subsequent articles in this series, concentrated aqueous mixtures of disinfection by-products were required for the two water treatment trains described in the preceding article (Miltner et al., 2008). To accomplish this, the fini...

  10. Disinfection by-products and extractable organic compounds in South African tap water

    Directory of Open Access Journals (Sweden)

    Carien Nothnagel

    2008-04-01

    Full Text Available An important step in urban purification of drinking water is disinfection by e.g. chlorination where potential pathogenic micro-organisms in the water supply are killed. The presence of organic material in natural water leads to the formation of organic by- products during disinfection. Over 500 of these disinfection by-products (DBPs have been identified and many more are estimated to form during the disinfection step. Several DBPs such as trihalomethanes (THMs, which is carcinogenic, poses serious health risks to the community. There is very few quantitative data available which realizes the actual levels of these compounds present in drinking water. The levels of four THMs present in drinking water were measured. It included chloroform, bromodichloromethane, chlorodibromomethane and bromoform. Although microbiological parameters are considered to get more attention than disinfection by-products, the measurement of the levels of these compounds in South-African drinking water is essential together with establishing minimum acceptable concentration levels. The target range for total trihalomethanes (TTHMs established by the US EPA at the end of 2003 is 0-0.08ug/mL. The aim of this paper is to create an awareness of the problem as well as presenting preliminary results obtained with the method of analysis. Preliminary results indicate that urgent attention must be given to the regulation and monitoring of DBPs in South African drinking water.

  11. Health impact of disinfection by-products in swimming pools

    Directory of Open Access Journals (Sweden)

    Cristina M. Villanueva

    2012-12-01

    Full Text Available This article is focused on the epidemiological evidence on the health impacts related to disinfection by-products (DBPs in swimming pools, which is a chemical hazard generated as an undesired consequence to reduce the microbial pathogens. Specific DBPs are carcinogenic, fetotoxic and/or irritant to the airways according to experimental studies. Epidemiological evidence shows that swimming in pools during pregnancy is not associated with an increased risk of reproductive outcomes. An epidemiological study suggested an increased risk of bladder cancer with swimming pool attendance, although evidence is inconclusive. A higher prevalence of respiratory symptoms including asthma is found among swimming pool workers and elite swimmers, although the causality of this association is unclear. The body of evidence in children indicates that asthma is not increased by swimming pool attendance. Overall, the available knowledge suggests that the health benefits of swimming outweigh the potential health risks of chemical contamination. However, the positive effects of swimming should be enhanced by minimising potential risks.

  12. DISINFECTION BY-PRODUCT FORMATION BY ALTERNATIVE DISINFECTANTS AND REMOVAL BY GRANULAR ACTIVATED CARBON

    Science.gov (United States)

    The effects of the use of the alternative disinfectants on the formation of halogenated disinfection by–products (DBPs) including total organic halide, trihalomethanes, haloacetic acids, haloacetonitriles, haloketones, chloral hydrate, and chloropicrin, were examined along ...

  13. CONTROL OF MICROBIAL CONTAMINANTS AND DISINFECTION BY-PRODUCTS (DBPS): COST AND PERFORMANCE

    Science.gov (United States)

    The USEPA is in the process of developing a sophisticated regulatory strategy in an attempt to balance the complex trade-offs in risks associated with controlling disinfectants and disinfection by-products (D/DBPs) in drinking water. EPA first attempted to control DBPs in 1974, w...

  14. Combining Mass Spectrometry and Toxicology for a Multi-Country European Epidemiologic Study on Drinking Water Disinfection By-Products

    Science.gov (United States)

    The HiWATE (Health Impacts of long-term exposure to disinfection by-products in drinking WATEr) project is the first systematic analysis that combines the epidemiology on adverse pregnancy outcomes with analytical chemistry and analytical biology in the European Union. This study...

  15. Genotoxicity of the disinfection by-products resulting from peracetic acid- or hypochlorite-disinfected sewage wastewater.

    Science.gov (United States)

    Crebelli, R; Conti, L; Monarca, S; Feretti, D; Zerbini, I; Zani, C; Veschetti, E; Cutilli, D; Ottaviani, M

    2005-03-01

    Wastewater disinfection is routinely carried out to prevent the spread of human pathogens present in wastewater effluents. To this aim, chemical and physical treatments are applied to the effluents before their emission in water bodies. In this study, the influence of two widely used disinfectants, peracetic acid (PAA) and sodium hypochlorite (NaClO), on the formation of mutagenic by-products was investigated. Wastewater samples were collected before and after disinfection, in winter and in summer, at a pilot plant installed in a municipal wastewater-treatment plant. Samples were adsorbed using silica C18 cartridges and the concentrates were tested for mutagenicity in the Salmonella typhimurium reversion test with strains TA98 and TA100. Non-concentrated water samples were tested with two plant genotoxicity assays (the Allium cepa root anaphase aberration test and the Tradescantia/micronucleus test). Mutagenicity assays in bacteria and in Tradescantia showed borderline mutagenicity in some of the wastewater samples, independent of the disinfection procedure applied. Negative results were obtained in the A. cepa anaphase aberration test. These results indicate that, in the conditions applied, wastewater disinfection with PAA and NaClO does not lead to the formation of significant amounts of genotoxic by-products.

  16. MUTAGENICITY AND DISINFECTION BY-PRODUCTS IN SURFACE DRINKING WATER DISINFECTED WITH PERACETIC ACID

    Science.gov (United States)

    The aims of this research were to study the influence of peracetic acid (PAA) on the formation of mutagens in surface waters used for human consumption and to assess its potential application for the disinfection of drinking water. The results obtained using PAA were compared to ...

  17. Determination of several common disinfection by-products in frozen foods.

    Science.gov (United States)

    Cardador, Maria Jose; Gallego, Mercedes

    2018-01-01

    Disinfected water and/or disinfectants are commonly used by the freezing industry in such processes as sanitising, washing, blanching, cooling and transporting the final product. For this reason, disinfection by-products (DBPs) can be expected in frozen foods. This study focused on the presence of DBPs in a wide variety of frozen vegetables, meats and fish. For this purpose, the 14 halogenated DBPs more prevalent in disinfected water were selected (four trihalomethanes, seven haloacetic acids, two haloacetonitriles and trichloronitromethane). Up to seven DBPs were found in vegetables, whereas only four DBPs were present in meats and fish, and at lower concentrations, since their contact with disinfected water is lower than in frozen vegetables. It is important to emphasise that trichloronitromethane (the most abundant nitrogenous DBP in disinfected water) was found for the first time in foods. Finally, it was concluded that the freezing process can keep the compounds stable longer than other preservation processes (viz. sanitising, canning) and, therefore, frozen foods present higher DBP concentrations than other food categories (minimally processed vegetables, or canned vegetables and meats).

  18. Secondary formation of disinfection by-products by UV treatment of swimming pool water

    DEFF Research Database (Denmark)

    Spiliotopoulou, Aikaterini; Hansen, Kamilla Marie Speht; Andersen, Henrik Rasmus

    2015-01-01

    Formation of disinfection by-products (DBPs) during experimental UV treatment of pool water has previously been reported with little concurrence between laboratory studies, field studies and research groups. In the current study, changes in concentration of seven out of eleven investigated volatile...

  19. Genotoxic Effects in Swimmers Exposed to Disinfection By-products in Indoor Swimming Pool

    Science.gov (United States)

    BACKGROUND: Exposure to disinfection by-products (DBPs) in drinking water has been associated with cancer risk, and a recent study found an increased bladder cancer risk among subjects attending swimming pools. OBJECTIVES: To evaluate whether swimming in pools is associated with ...

  20. Environmental and personal determinants of the uptake of disinfection by-products during swimming

    NARCIS (Netherlands)

    Font-Ribera, Laia; Kogevinas, Manolis; Schmalz, Christina; Zwiener, Christian; Marco, Esther; Grimalt, Joan O; Liu, Jiaqi; Zhang, Xiangru; Mitch, William; Critelli, Rossana; Naccarati, Alessio; Heederik, Dick; Spithoven, Jack; Arjona, Lourdes; de Bont, Jeroen; Gracia-Lavedan, Esther; Villanueva, Cristina M

    BACKGROUND: Trihalomethanes (THMs) in exhaled breath and trichloroacetic acid (TCAA) in urine are internal dose biomarkers of exposure to disinfection by-products (DBPs) in swimming pools. OBJECTIVE: We assessed how these biomarkers reflect the levels of a battery of DBPs in pool water and

  1. Seasonal evaluation of disinfection by-products throughout two full-scale drinking water treatment plants.

    Science.gov (United States)

    Zhong, Xin; Cui, Chongwei; Yu, Shuili

    2017-07-01

    Carbonyl compounds can occur alpha-hydrogens or beta-diketones substitution reactions with disinfectants contributed to halogenated by-products formation. The objective of this research was to study the occurrence and fate of carbonyl compounds as ozonation by-products at two full-scale drinking water treatment plants (DWTPs) using different disinfectants for one year. The quality of the raw water used in both plants was varied according to the season. The higher carbonyl compounds concentrations were found in raw water in spring. Up to 15 (as the sum of both DWTPs) of the 24 carbonyl compounds selected for this work were found after disinfection. The dominant carbonyl compounds were formaldehyde, glyoxal, methyl-glyoxal, fumaric, benzoic, protocatechuic and 3-hydroxybenzoic acid at both DWTPs. In the following steps in each treatment plant, the concentration patterns of these carbonyl compounds differed depending on the type of disinfectant applied. Benzaldehyde was the only aromatic aldehyde detected after oxidation with ozone in spring. As compared with DWTP 1, five new carbonyl compounds were formed (crotonaldehyde, benzaldehyde, formic, oxalic and malonic acid) disinfection by ozone, and the levels of the carbonyl compounds increased. In addition, pre-ozonation (PO) and main ozonation (OZ) increased the levels of carbonyl compounds, however coagulation/flocculation (CF), sand filtration (SF) and granular activated carbon filtration (GAC) decreased the levels of carbonyl compounds. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. CHO cell cytotoxicity and genotoxicity analyses of disinfection by-products: An updated review

    Institute of Scientific and Technical Information of China (English)

    Elizabeth D.Wagner; Michael J.Plewa

    2017-01-01

    The disinfection of drinking water is an important public health service that generates high quality,safe and palatable tap water.The disinfection of drinking water to reduce waterborne disease was an outstanding public health achievement of the 20th century.An unintended consequence is the reaction of disinfectants with natural organic matter,anthropogenic contaminants and bromide/iodide to form disinfection by-products (DBPs).A large number of DBPs are cytotoxic,neurotoxic,mutagenic,genotoxic,carcinogenic and teratogenic.Epidemiological studies demonstrated low but significant associations between disinfected drinking water and adverse health effects.The distribution of DBPs in disinfected waters has been well defined by advances in high precision analytical chemistry.Progress in the analytical biology and toxicology of DBPs has been forthcoming.The objective of this review was to provide a detailed presentation of the methodology for the quantitative,comparative analyses on the induction of cytotoxicity and genotoxicity of 103 DBPs using an identical analytical biological platform and endpoints.A single Chinese hamster ovary cell line was employed in the assays.The data presented are derived from papers published in the literature as well as additional new data and represent the largest direct quantitative comparison on the toxic potency of both regulated and emerging DBPs.These data may form the foundation of novel research to define the major forcing agents of DBP-mediated toxicity in disinfected water and may play an important role in achieving the goal of making safe drinking water better.

  3. Disinfection aboard cruise liners and naval units: formation of disinfection by-products using chlorine dioxide in different qualities of drinking water.

    Science.gov (United States)

    Ufermann, Petra; Petersen, Hauke; Exner, Martin

    2011-12-01

    The world-wide deployment of cruise liners and naval units has caused an increased need for the disinfection of drinking water. The main cause for this is the unknown quality of drinking water in foreign harbours--besides the formation of bio-films due to the climatically disadvantageous conditions in the operational area. Water conduits on board are currently disinfected with calcium hypochlorite in case of microbiological contamination. Chemical and physical analyses after disinfection with calcium hypochlorite have shown that organic by-products consisting of trihalomethanes develop in considerable amounts during disinfection. Furthermore, the method is susceptible to handling errors and thus often leads to insufficient disinfection results. Hitherto, the use of other disinfection methods allowed by government regulations, especially chlorine dioxide, is not widely spread. Unlike disinfection with calcium hypochlorite, chlorine dioxide does not lead to the formation of trihalomethanes. Typical disinfection by-products (DBP) are the anions chlorite and chlorate, which are formed in oxidative processes. The formation conditions of these anions have not yet been elucidated. For this reason, the probability of the generation of inorganic by-products after disinfection with chlorine dioxide has been determined, and their occurrence in drinking water on board has been examined with respect to a possible correlation between water quality and the formation of chlorate and chlorite. Therefore, a chromatographic method was developed and validated in order to determine the periodical development of chlorate and chlorite from chorine dioxide in purified water at different pH-values as well as in actual drinking water samples from water conduits on board. The formation of the by-products chlorite and chlorate after disinfection with chlorine dioxide is influenced neither by pH-value nor by chemical properties of the disinfected water. Considering the examined conditions

  4. Formation of nitrogenous disinfection by-products in 10 chlorinated and chloraminated drinking water supply systems.

    Science.gov (United States)

    Liew, Deborah; Linge, Kathryn L; Joll, Cynthia A

    2016-09-01

    The presence of nitrogenous disinfection by-products (N-DBPs) in drinking water supplies is a public health concern, particularly since some N-DBPs have been reported to be more toxic than the regulated trihalomethanes and haloacetic acids. In this paper, a comprehensive evaluation of the presence of N-DBPs in 10 drinking water supply systems in Western Australia is presented. A suite of 28 N-DBPs, including N-nitrosamines, haloacetonitriles (HANs), haloacetamides (HAAms) and halonitromethanes (HNMs), were measured and evaluated for relationships with bulk parameters in the waters before disinfection. A number of N-DBPs were frequently detected in disinfected waters, although at generally low concentrations (water, N-DBP concentrations were significantly correlated with dissolved organic carbon (DOC) and ammonia, and these, in addition to high bromide in one of the waters, led to elevated concentrations of brominated HANs (26.6 μg/L of dibromoacetonitrile). There were significant differences in the occurrence of all classes of N-DBPs between chlorinated and chloraminated waters, except for HNMs, which were detected at relatively low concentrations in both water types. Trends observed in one large distribution system suggest that N-DBPs can continue to form or degrade within distribution systems, and redosing of disinfectant may cause further by-product formation.

  5. Disinfection by-products/precursor control using an innovative treatment process -- high energy electron beam irradiation

    International Nuclear Information System (INIS)

    Sawal, K.; Millington, B.; Slifker, R.A.; Cooper, W.J.; Nickelsen, M.G.; Kurucz, C.N.; Waite, T.D.

    1993-01-01

    When waters containing naturally occurring humic substances, precursors, are chlorinated, reaction (disinfection) by-products (DBPs) that may compromise the chemical water quality of the drinking water are formed. Two options exist for the treatment of THMs and other DBPs, removal of precursor material prior to chlorination, or destruction of the by-products once they are formed. The authors have initiated a study using an innovative process, high energy electron beam irradiation, as an alternative treatment for the destruction of toxic organic compounds. Preliminary studies indicated that the process would also be effective in the removal of precursors. An added advantage of this process is that is would serve as a primary disinfectant, destroying any toxic compounds in the source water and may assist in the removal of algae and cyanobacteria toxins. This paper discusses studies in precursor removal and control of THMs

  6. DOES MICRO LC/MS OFFER ADVANTAGES OVER CONVENTIONAL LC/MS IN IDENTIFYING DISINFECTION BY-PRODUCTS

    Science.gov (United States)

    Lower maximum contaminant levels (MCLs) of disinfection by-products were set for drinking water municipalities by the Stage 1 DBP Rule in November, 1998. With these new regulations, additional water treatment plants are expected to choose alternative disinfectants to chlorine. Al...

  7. Removal of disinfection by-product precursors by coagulation and an innovative suspended ion exchange process.

    Science.gov (United States)

    Metcalfe, David; Rockey, Chris; Jefferson, Bruce; Judd, Simon; Jarvis, Peter

    2015-12-15

    This investigation aimed to compare the disinfection by-product formation potentials (DBPFPs) of three UK surface waters (1 upland reservoir and 2 lowland rivers) with differing characteristics treated by (a) a full scale conventional process and (b) pilot scale processes using a novel suspended ion exchange (SIX) process and inline coagulation (ILCA) followed by ceramic membrane filtration (CMF). Liquid chromatography-organic carbon detection analysis highlighted clear differences between the organic fractions removed by coagulation and suspended ion exchange. Pretreatments which combined SIX and coagulation resulted in significant reductions in dissolved organic carbon (DOC), UV absorbance (UVA), trihalomethane and haloacetic acid formation potential (THMFP, HAAFP), in comparison with the SIX or coagulation process alone. Further experiments showed that in addition to greater overall DOC removal, the processes also reduced the concentration of brominated DBPs and selectively removed organic compounds with high DBPFP. The SIX/ILCA/CMF process resulted in additional removals of DOC, UVA, THMFP, HAAFP and brominated DBPs of 50, 62, 62, 62% and 47% respectively compared with conventional treatment. Copyright © 2015. Published by Elsevier Ltd.

  8. Halogenated by-products of disinfecting ozonised recreational waters; Subproductos halaogenados de desinfeccion en aguas recreacionales ozonizadas

    Energy Technology Data Exchange (ETDEWEB)

    Goma i Huguet, A.; Quintana i Comte, J.; Soler i Vilaro, J.

    2005-07-01

    Recreational water like the present in swimming pools suffers, more than water from supply, formation of certain by-products in the local disinfection system because a mechanism of accumulation. Using advanced oxidation process, like onization, drives to a reduction of such an effect. Assessment of the presence of these disinfection by-products with and without onization, as well as the discussion of certain key aspects of how to ozonate, are the aim of this paper. (Author) 7 refs.

  9. Socioeconomic status and exposure to disinfection by-products in drinking water in Spain

    Directory of Open Access Journals (Sweden)

    Serra Consol

    2011-03-01

    Full Text Available Abstract Background Disinfection by-products in drinking water are chemical contaminants that have been associated with cancer and other adverse effects. Exposure occurs from consumption of tap water, inhalation and dermal absorption. Methods We determined the relationship between socioeconomic status and exposure to disinfection by-products in 1271 controls from a multicentric bladder cancer case-control study in Spain. Information on lifetime drinking water sources, swimming pool attendance, showering-bathing practices, and socioeconomic status (education, income was collected through personal interviews. Results The most highly educated subjects consumed less tap water (57% and more bottled water (33% than illiterate subjects (69% and 17% respectively, p-value = 0.003. These differences became wider in recent time periods. The time spent bathing or showering was positively correlated with attained educational level (p Conclusions The most highly educated subjects were less exposed to chlorination by-products through ingestion but more exposed through dermal contact and inhalation in pools and showers/baths. Health risk perceptions and economic capacity may affect patterns of water consumption that can result in differences in exposure to water contaminants.

  10. Effect of drinking water disinfection by-products in human peripheral blood lymphocytes and sperm.

    Science.gov (United States)

    Ali, Aftab; Kurzawa-Zegota, Malgorzata; Najafzadeh, Mojgan; Gopalan, Rajendran C; Plewa, Michael J; Anderson, Diana

    2014-12-01

    Drinking water disinfection by-products (DBPs) are generated by the chemical disinfection of water and may pose hazards to public health. Two major classes of DBPs are found in finished drinking water: haloacetic acids (HAAs) and trihalomethanes (THMs). HAAs are formed following disinfection with chlorine, which reacts with iodide and bromide in the water. Previously the HAAs were shown to be cytotoxic, genotoxic, mutagenic, teratogenic and carcinogenic. To determine the effect of HAAs in human somatic and germ cells and whether oxidative stress is involved in genotoxic action. In the present study both somatic and germ cells have been examined as peripheral blood lymphocytes and sperm. The effects of three HAA compounds: iodoacetic acid (IAA), bromoacetic acid (BAA) and chloroacetic acid (CAA) were investigated. After determining appropriate concentration responses, oxygen radical involvement with the antioxidants, butylated hydroxanisole (BHA) and the enzyme catalase, were investigated in the single cell gel electrophoresis (Comet) assay under alkaline conditions, >pH 13 and the micronucleus assay. In the Comet assay, BHA and catalase were able to reduce DNA damage in each cell type compared to HAA alone. In the micronucleus assay, micronuclei (MNi) were found in peripheral lymphocytes exposed to all three HAAs and catalase and BHA were in general, able to reduce MNi induction, suggesting oxygen radicals play a role in both assays. These observations are of concern to public health since both human somatic and germ cells show similar genotoxic responses. Copyright © 2014. Published by Elsevier B.V.

  11. Degradation kinetics of organic chloramines and formation of disinfection by-products during chlorination of creatinine.

    Science.gov (United States)

    Zhang, Tianyang; Xu, Bin; Wang, Anqi; Cui, Changzheng

    2018-03-01

    Organic chloramines can interfere with the measurement of effective combined chlorine in chlorinated water and are potential intermediate products of highly toxic disinfection by-products (DBPs). In order to know more about the degradation and transformation of organic chloramines, a typical organic chloramine precursor creatinine was selected for investigation and a corresponding individual organic chloramine chlorocreatinine was prepared in this study. The preparation condition of chlorocreatinine by chlorination was established as chlorine/creatinine = 1 M/M, reaction time = 2 h and pH = 7.0. Then the degradation kinetics of chlorocreatinine during further chlorination was studied, and a second-order rate constant of 1.16 (±0.14) M -1 s -1 was obtained at pH 7.0. Solution pH significantly influenced the degradation rate, and the elementary rate constants of chlorocreatinine with HOCl+H + , HOCl, OCl - and chlorocreatinine - with OCl - were calculated as 2.43 (±1.55) × 10 4  M -2  s -1 , 1.05 (±0.09) M -1 s -1 , 2.86 (±0.30) M -1 s -1 and 3.09 (±0.24) M -1 s -1 , respectively. Besides, it was found that chlorocreatinine could be further converted into several C-DBPs (chloroform and trichloroacetone) and N-DBPs (dichloroacetonitrile (DCAN) and trichloronitromethane (TCNM)) during chlorination. The total yield of DBPs increased obviously with increasing pH, especially for TCNM. In addition, the presence of humic acid in creatinine solution could increase the formation of DCAN obviously during chlorination. Based on the UPLC-Q-TOF-MS analysis, the conversion pathways of chlorocreatinine were proposed. Several kinds of intermediate products were also identified as organic chloramines and some of them could even exist stably during the further chlorination. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. The study of interrelationship between raw water quality parameters, chlorine demand and the formation of disinfection by-products

    Science.gov (United States)

    Abdullah, Md. Pauzi; Yee, Lim Fang; Ata, Sadia; Abdullah, Abass; Ishak, Basar; Abidin, Khairul Nidzham Zainal

    Disinfection is the most crucial process in the treatment of drinking water supply and is the final barrier against bacteriological impurities in drinking water. Chlorine is the primary disinfectant used in the drinking water treatment process throughout Malaysia. However, the occurrence of various disinfection by-products such as trihalomethanes (THM) and haloacetic acids created a major issue on the potential health hazards which may pose adverse health effects in both human and animals. To simulate real water treatment conditions and to represent the conditions inherent in a tropical country, this study was performed at an urbanized water treatment plant with a daily production of about 549,000 m 3 of treated water. The purpose of this work is to examine the relationship between the water quality parameters in the raw water with chlorine demand and the formation of disinfection by-products. This study also investigated the possibility of the statistical model applications for the prediction of chlorine demand and the THM formation. Two models were developed to estimate the chlorine demand and the THM formation. For the statistical evaluation, correlation and simple linear regression analysis were conducted using SPSS. The results of Kolmogorov-Smirnov test for the estimation of goodness-of-fit of the dependent variables of the models to the normal distribution showed that all the dependent variables followed the normal distribution at significance level of 0.05. Good linear correlations were observed between the independent parameters and formation of THM and the chlorine demand. This study also revealed that ammonia and the specific ultraviolet absorbent (SUVA) were the function of chlorine consumption in the treatment process. Chlorine dosage and SUVA increase the yield of THM. Chlorine demand and THM formation was moderately sensitive, but significant to the pH. The level of significance ( α) for the statistical tests and the inclusion of a variable in the

  13. Predictive model for disinfection by-product in Alexandria drinking water, northern west of Egypt.

    Science.gov (United States)

    Abdullah, Ali M; Hussona, Salah El-dien

    2013-10-01

    Chlorine has been utilized in the early stages of water treatment processes as disinfectant. Disinfection for drinking water reduces the risk of pathogenic infection but may pose a chemical threat to human health due to disinfection residues and their by-products (DBP) when the organic and inorganic precursors are present in water. In the last two decades, many modeling attempts have been made to predict the occurrence of DBP in drinking water. Models have been developed based on data generated in laboratory-scale and field-scale investigations. The objective of this paper is to develop a predictive model for DBP formation in the Alexandria governorate located at the northern west of Egypt based on field-scale investigations as well as laboratory-controlled experimentations. The present study showed that the correlation coefficient between trihalomethanes (THM) predicted and THM measured was R (2)=0.88 and the minimum deviation percentage between THM predicted and THM measured was 0.8 %, the maximum deviation percentage was 89.3 %, and the average deviation was 17.8 %, while the correlation coefficient between dichloroacetic acid (DCAA) predicted and DCAA measured was R (2)=0.98 and the minimum deviation percentage between DCAA predicted and DCAA measured was 1.3 %, the maximum deviation percentage was 47.2 %, and the average deviation was 16.6 %. In addition, the correlation coefficient between trichloroacetic acid (TCAA) predicted and TCAA measured was R (2)=0.98 and the minimum deviation percentage between TCAA predicted and TCAA measured was 4.9 %, the maximum deviation percentage was 43.0 %, and the average deviation was 16.0 %.

  14. Ozone and hydrogen peroxide applications for disinfection by-products control in drinking water

    International Nuclear Information System (INIS)

    Collivignarelli, C.; Sorlini, S.; Riganti, V.

    2001-01-01

    A great interest has been developed during the last years for ozone in drinking water treatments thanks to its strong oxidant and disinfectant power and for its efficiency in disinfection by-products (DBPs) precursors removal. However ozonization produces some specific DBPs, such as aldehydes and ketones; moreover, the presence of bromide in raw water engages ozone in a complex cycle in which both organic bromide and inorganic bromate are end products. In this paper the combination of hydrogen peroxide with ozone (known as peroxone process) and the ozone alone process were experimented on one surface water coming from the lake of Brugneto (Genova) in order to investigate bromate formation and trihalomethanes precursors removal during the oxidation process. The results show that the advanced peroxone process can be applied for bromate reduction (about 30-40%) with better results in comparison with the ozone alone process, while no advantages are shown for THMs precursors removal. The addition of in-line filtration step after pre-oxidation improves both bromate and THMs precursors removal, particularly with increasing hydrogen peroxide/ozone ratio in the oxidation step [it

  15. Detection of genotoxic effects of drinking water disinfection by-products using Vicia faba bioassay.

    Science.gov (United States)

    Hu, Yu; Tan, Li; Zhang, Shao-Hui; Zuo, Yu-Ting; Han, Xue; Liu, Na; Lu, Wen-Qing; Liu, Ai-Lin

    2017-01-01

    Plant-based bioassays have gained wide use among the toxicological and/or ecotoxicological assessment procedures because of their simplicity, sensitivity, low cost, and reliability. The present study describes the use of Vicia faba (V. faba) micronucleus (MN) test and V. faba comet assay in the evaluation of the genotoxic potential of disinfection by-products (DBPs) commonly found in chlorine-disinfected drinking water. Five haloacetic acids and three halogenated acetonitriles were chosen as representatives of DBPs in this study because they are of potentially great public health risk. Results of the MN test indicated that monochloroacetic acid (MCA), monobromoacetic acid (MBA), dichloroacetic acid (DCA), dibromoacetic acid (DBA), trichloroacetic acid (TCA), and trichloroacetonitrile (TCAN) caused a statistically significant increase in MN frequency in V. faba root tip cells. However, no genotoxic response was observed for dichloroacetonitrile (DCAN) and dibromoacetonitrile (DBAN). Results of the comet assay showed that all tested DBPs induced a statistically significant increase in genomic DNA damage to V. faba root tip cells. On considering the capacity to detect genomic damage of a different nature, we suggest that a combination of V. faba MN test and V. faba comet assay is a useful tool for the detection of genotoxic effects of DBPs. It is worthy of assessing the feasibility of using V. faba comet assay combined with V. faba MN test to screen for the genotoxic activity of chlorinated drinking water in future work.

  16. Evidence of arsenic release promoted by disinfection by-products within drinking-water distribution systems.

    Science.gov (United States)

    Andra, Syam S; Makris, Konstantinos C; Botsaris, George; Charisiadis, Pantelis; Kalyvas, Harris; Costa, Costas N

    2014-02-15

    Changes in disinfectant type could trigger a cascade of reactions releasing pipe-anchored metals/metalloids into finished water. However, the effect of pre-formed disinfection by-products on the release of sorbed contaminants (arsenic-As in particular) from drinking water distribution system pipe scales remains unexplored. A bench-scale study using a factorial experimental design was performed to evaluate the independent and interaction effects of trihalomethanes (TTHM) and haloacetic acids (HAA) on arsenic (As) release from either scales-only or scale-biofilm conglomerates (SBC) both anchored on asbestos/cement pipe coupons. A model biofilm (Pseudomonas aeruginosa) was allowed to grow on select pipe coupons prior experimentation. Either TTHM or HAA individual dosing did not promote As release from either scales only or SBC, detecting water. In the case of scales-only coupons, the combination of the highest spike level of TTHM and HAA significantly (pwater in pipe networks remains to be investigated in the field. Copyright © 2013 Elsevier B.V. All rights reserved.

  17. Effect of Permanganate Preoxidation to Natural Organic Matter and Disinfection by-Products Formation Potential Removal

    Science.gov (United States)

    Hidayah, E. N.; Yeh, H. H.

    2018-01-01

    Laboratory scale experiments was conducted to examine effect of permanganate (KMnO4) peroxidation in characterizing and to remove natural organic matter (NOM) in source water. The experimental results shows that increasing permanganate dosage could decreased aromatic matter, as indicated by decreasing UV254 and SUVA value about 23% and 28%, respectively. It seems that permanganate preoxidation caused the breakdown of high molecular weight (MW) organics into low MW ones, as represented by increasing NPDOC about 10%. Further, disinfection by-products formation potential (DBPFP) in terms of trihalomethanes formation potential (THMFP) and haloacetic acid formation potential (HAAP) decreased about 15% and 23%, respectively. HAAFP removal is higher than THMFP removal and that DPBFP removal is consistent with UV254 and NPDOC removal.

  18. New chlorinated amphetamine-type-stimulants disinfection-by-products formed during drinking water treatment.

    Science.gov (United States)

    Huerta-Fontela, Maria; Pineda, Oriol; Ventura, Francesc; Galceran, Maria Teresa

    2012-06-15

    Previous studies have demonstrated high removal rates of amphetamine-type-stimulants (ATSs) through conventional drinking water treatments; however the behaviour of these compounds through disinfection steps and their transformation into disinfection-by-products (DBPs) is still unknown. In this work, for the first time, the reactivity of some ATSs such as amphetamine, methamphetamine, 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxymethamphetamine (MDMA) and 3,4-methylenedioxyethylamphetamine (MDEA) with chlorine has been investigated under simulated and real drinking water treatment conditions in order to evaluate their ability to give rise to transformation products. Two new DBPs from these illicit drugs have been found. A common chlorinated-by-product (3-chlorobenzo)-1,3-dioxole, was identified for both MDA and MDEA while for MDMA, 3-chlorocatechol was found. The presence of these DBPs in water samples collected through drinking water treatment was studied in order to evaluate their formation under real conditions. Both compounds were generated through treatment from raw river water samples containing ATSs at concentration levels ranging from 1 to 15 ng/L for MDA and from 2.3 to 78 ng/L for MDMA. One of them, (3-chlorobenzo)-1,3-dioxole, found after the first chlorination step, was eliminated after ozone and GAC treatment while the MDMA DBP mainly generated after the postchlorination step, showed to be recalcitrant and it was found in final treated waters at concentrations ranging from 0.5 to 5.8 ng/L. Copyright © 2012 Elsevier Ltd. All rights reserved.

  19. Modelling formation of disinfection by-products in water distribution: Optimisation using a multi-objective evolutionary algorithm

    KAUST Repository

    Radhakrishnan, Mohanasundar; Pathirana, Assela; Ghebremichael, Kebreab A.; Amy, Gary L.

    2012-01-01

    Concerns have been raised regarding disinfection by-products (DBPs) formed as a result of the reaction of halogen-based disinfectants with DBP precursors. In order to appreciate the chemical and biological tradeoffs, it is imperative to understand the formation trends of DBPs and their spread in the distribution network. However, the water at a point in a complex distribution system is a mixture from various sources, whose proportions are complex to estimate and requires advanced hydraulic analysis. To understand the risks of DBPs and to develop mitigation strategies, it is important to understand the distribution of DBPs in a water network, which requires modelling. The goal of this research was to integrate a steady-state water network model with a particle backtracking algorithm and chlorination as well as DBPs models in order to assess the tradeoffs between biological and chemical risks in the distribution network. A multi-objective optimisation algorithm was used to identify the optimal proportion of water from various sources, dosages of alum, and dosages of chlorine in the treatment plant and in booster locations to control the formation of chlorination DBPs and to achieve a balance between microbial and chemical risks. © IWA Publishing 2012.

  20. Modelling formation of disinfection by-products in water distribution: Optimisation using a multi-objective evolutionary algorithm

    KAUST Repository

    Radhakrishnan, Mohanasundar

    2012-05-01

    Concerns have been raised regarding disinfection by-products (DBPs) formed as a result of the reaction of halogen-based disinfectants with DBP precursors. In order to appreciate the chemical and biological tradeoffs, it is imperative to understand the formation trends of DBPs and their spread in the distribution network. However, the water at a point in a complex distribution system is a mixture from various sources, whose proportions are complex to estimate and requires advanced hydraulic analysis. To understand the risks of DBPs and to develop mitigation strategies, it is important to understand the distribution of DBPs in a water network, which requires modelling. The goal of this research was to integrate a steady-state water network model with a particle backtracking algorithm and chlorination as well as DBPs models in order to assess the tradeoffs between biological and chemical risks in the distribution network. A multi-objective optimisation algorithm was used to identify the optimal proportion of water from various sources, dosages of alum, and dosages of chlorine in the treatment plant and in booster locations to control the formation of chlorination DBPs and to achieve a balance between microbial and chemical risks. © IWA Publishing 2012.

  1. EPIDEMIOLOGIC EVALUATION OF THE POTENTIAL ASSOCIATION BETWEEN EXPOSURE TO DRINKING WATER DISINFECTION BY-PRODUCTS (DBP) AND SEMEN QUALITY

    Science.gov (United States)

    Epidemiologic Evaluation of the Potential Association between Exposure to Drinking Water Disinfection By-Products and Semen Quality*Morris, R; +Olshan, A; +Lansdell, L; *Jeffay, S; *Strader, L; *Klinefelter, G; *Perreault, S.* U.S. EPA/ORD/NHEERL/RTD/GEEBB, Research ...

  2. Effect of medium-pressure UV-lamp treatment on disinfection by-products in chlorinated seawater swimming pool waters

    DEFF Research Database (Denmark)

    Cheema, Waqas Akram; Manasfi, Tarek; Kaarsholm, Kamilla Marie Speht

    2017-01-01

    Several brominated disinfection by-products (DBPs) are formed in chlorinated seawater pools, due to the high concentration of bromide in seawater. UV irradiation is increasingly employed in freshwater pools, because UV treatment photodegrades harmful chloramines. However, in freshwater pools it has...

  3. Reproductive toxicity of a mixture of regulated drinking-water disinfection by-products in a multigenerational rat bioassay

    Science.gov (United States)

    BACKGROUND:Trihalomethanes (THMs) and haloaretic acids (HAAs) are regulated disinfection by-products (DBPs); their joint reproductive toxicity in drinking water is unknown.OBJECTIVE: We aimed to evaluate a drinking water mixture of the four regulated THMs and five regulated HAAs ...

  4. THE OCCURRENCE OF DISINFECTION BY-PRODUCTS OF HEALTH CONCERN IN DRINKING WATER: RESULTS OF A NATIONWIDE DBP OCCURRENCE STUDY

    Science.gov (United States)

    The motivation for this Nationwide Disinfection By-product (DBP) Occurrence Study was two-fold: First, more than 500 DBPs have been reported in the literature, yet there is almost no quantitative occurrence information for most. As a result, there is significant uncertainty ove...

  5. The determination and fate of disinfection by-products from ozonation of polluted raw water

    International Nuclear Information System (INIS)

    Huang, W.-J.; Fang, G.-C.; Wang, C.-C.

    2005-01-01

    The major disinfection by-products (DBPs) resulting from ozone treatment of polluted surface water were investigated. By-products of either health concern or which may contribute to biological instability of treated drinking water were investigated. The major DBPs were analyzed in two fractions: carbonyl compounds and brominated organic compounds. The natural organic matter (NOM) was also isolated and fractionated from polluted water for subsequent ozonation and DBPs identification under conditions of typical drinking treatment. The main identified carbonyl compounds were low molecular weight carboxylic acids, benzoic compounds, aliphatic aldehydes and odorous aldehydes, respectively. Brominated organics were also found in ozonated water, including bromoform (CHBr 3 ), monobromoacetic acid (MBAA), dibromoacetic acid (DBAA), 2,4-dibromophenol (2,4-DBP) and dibromoacetonitrile (DBAN), respectively. It was also found that the characteristic of organic precursors have significant influences on brominated organic by-products formation. Humic acid demonstrated the highest CHBr 3 , DBAA and 2,4-DBP formations, whereas hydrophilic neutral produced less CHBr 3 and 2,4-DBP than the rest of the organic fractions but produced the highest amount of DBAN. In addition to the other target compounds, a total of 59 different organic compounds were detected by means of gas chromatograph/high-resolution electron-impact mass spectrometry (GC/EI-MS) detection and tentatively identified using mass spectral library searching, mainly aromatics, acids/esters, alcohols, aldehydes, phthalates and amines/amino acids were analyzed. The percentage of elimination or formation levels reached during ozonation is also discussed in this study

  6. Disinfection By-Product Exposures and the Risk of Specific Cardiac Birth Defects

    Science.gov (United States)

    Wright, J. Michael; Evans, Amanda; Kaufman, John A.; Rivera-Núñez, Zorimar; Narotsky, Michael G.

    2016-01-01

    Background: Epidemiological studies suggest that women exposed to disinfection by-products (DBPs) have an increased risk of delivering babies with cardiovascular defects (CVDs). Objective: We examined nine CVDs in relation to categorical DBP exposures including bromoform, chloroform, dibromochloromethane (DBCM), bromodichloromethane (BDCM), monobromoacetic acid (MBAA), dichloroacetic acid (DCAA), trichloroacetic acid (TCAA), and summary DBP measures (HAA5, THMBr, THM4, and DBP9). Methods: We calculated adjusted odds ratios (aORs) in a case–control study of birth defects in Massachusetts with complete quarterly 1999–2004 trihalomethane (THM) and haloacetic acid (HAA) data. We randomly matched 10 controls each to 904 CVD cases based on week of conception. Weight-averaged aggregate first-trimester DBP exposures were assigned to individuals based on residence at birth. Results: We detected associations for tetralogy of Fallot and the upper exposure categories for TCAA, DCAA, and HAA5 (aOR range, 3.34–6.51) including positive exposure–response relationships for DCAA and HAA5. aORs consistent in magnitude were detected between atrial septal defects and bromoform (aOR = 1.56; 95% CI: 1.01, 2.43), as well as DBCM, chloroform, and THM4 (aOR range, 1.26–1.67). Ventricular septal defects (VSDs) were associated with the highest bromoform (aOR = 1.85; 95% CI: 1.20, 2.83), MBAA (aOR = 1.81; 95% CI: 0.85, 3.84), and DBCM (aOR = 1.54; 95% CI: 1.00, 2.37) exposure categories. Conclusions: To our knowledge, this is the first birth defect study to develop multi-DBP adjusted regression models as well as the first CVD study to evaluate HAA exposures and the second to evaluate bromoform exposures. Our findings, therefore, inform exposure specificity for the consistent associations previously reported between THM4 and CVDs including VSDs. Citation: Wright JM, Evans A, Kaufman JA, Rivera-Núñez Z, Narotsky MG. 2017. Disinfection by-product exposures and the risk of specific

  7. Associations Between Disinfection By-Product Exposures and Craniofacial Birth Defects.

    Science.gov (United States)

    Kaufman, John A; Wright, J Michael; Evans, Amanda; Rivera-Núñez, Zorimar; Meyer, Amy; Narotsky, Michael G

    2018-02-01

    The aim of this study was to examine associations between craniofacial birth defects (CFDs) and disinfection by-product (DBP) exposures, including the sum of four trihalomethanes (THM4) and five haloacetic acids (HAA5) (ie, DBP9). We calculated first trimester adjusted odds ratios (aORs) for different DBPs in a matched case-control study of 366 CFD cases in Massachusetts towns with complete 1999 to 2004 THM and HAA data. We detected elevated aORs for cleft palate with DBP9 (highest quintile aOR = 3.52; 95% CI: 1.07, 11.60), HAA5, trichloroacetic acid (TCAA), and dichloroacetic acid. We detected elevated aORs for eye defects with TCAA and chloroform. This is the first epidemiological study of DBPs to examine eye and ear defects, as well as HAAs and CFDs. The associations for cleft palate and eye defects highlight the importance of examining specific defects and DBPs beyond THM4.

  8. Formation of N-nitrosodimethylamine (NDMA) from reaction of monochloramine: a new disinfection by-product.

    Science.gov (United States)

    Choi, Junghoon; Valentine, Richard L

    2002-02-01

    Studies have been conducted specifically to investigate the hypothesis that N-nitrosodimethylamine (NDMA) can be produced by reactions involving monochloramine. Experiments were conducted using dimethylamine (DMA) as a model precursor. NDMA was formed from the reaction between DMA and monochloramine indicating that it should be considered a potential disinfection by-product. The formation of NDMA increased with increased monochloramine concentration and showed maximum in yield when DMA was varied at fixed monochloramine concentrations. The mass spectra of the NDMA formed from DMA and 15N isotope labeled monochloramine (15NH2Cl) showed that the source of one of the nitrogen atoms in the nitroso group in NDMA was from monochloramine. Addition of 0.05 and 0.5 mM of preformed monochloramine to a secondarily treated wastewater at pH 7.2 also resulted in the formation of 3.6 and 111 ng/L of NDMA, respectively, showing that this is indeed an environmentally relevant NDMA formation pathway. The proposed NDMA formation mechanism consists of (i) the formation of 1,1-dimethylhydrazine (UDMH) intermediate from the reaction of DMA with monochloramine followed by, (ii) the oxidation of UDMH by monochloramine to NDMA, and (iii) the reversible chlorine transfer reaction between monochloramine and DMA which is parallel to (i). We conclude that reactions involving monochloramine in addition to classical nitrosation reactions are potentially important pathways for NDMA formation.

  9. Origin of low-molecular mass aldehydes as disinfection by-products in beverages.

    Science.gov (United States)

    Serrano, María; Gallego, Mercedes; Silva, Manuel

    2017-09-01

    A novel, simple and automatic method based on static headspace-gas chromatography-mass spectrometry has been developed to determine 10 low-molecular mass aldehydes that can be found in beverages, coming from the treated water used in their production. These aldehydes are the most frequently found in treated water as water disinfection by-products, so they can be used as indicators of the addition of treated water to beverages. The study covered a large number of fruit juices and soft drinks. The presence of the whole array of analytes is related to the contact with treated water during beverage production, mainly by the addition of treated water as ingredient. In particular, propionaldehyde, valeraldehyde and benzaldehyde can be used as indicators of the addition of treated water in these kinds of beverages. Among the ten aldehydes, only formaldehyde and acetaldehyde are naturally present in all kinds of fruit, and their concentrations are related to stage of the ripening of the fruit.

  10. Exopolymeric substances from drinking water biofilms: Dynamics of production and relation with disinfection by products.

    Science.gov (United States)

    Lemus Pérez, M F; Rodríguez Susa, M

    2017-06-01

    Exopolymeric substances (EPS) as an external matrix of biofilm could react with disinfectants in drinking water networks forming disinfection by-products (DBP). Based on an experimental setup using two chlorine conditions-biofilm 1 (2.6 ± 0.8 mgCl/L) and biofilm 2 (0.7 ± 0.2 mg Cl/L)-samples of biofilms were recovered during 9 campaigns and EPS were extracted. Analyses of SUVA, fluorescence and amino acid (AA) content were carried out on the EPS to observe variation over time and correlations with DBP formation potential (DBP fp ) after chlorination. SUVA values were under 2 L/mgC*m showing that both EPS were hydrophilic. Slightly higher SUVA in biofilm 2 with low variation over time was observed. Fluorescence showed that aromatic proteins and fulvic like substances were the principal components and increased in biofilm 1 over time. AA decreased with time, and higher values of alanine, threonine, proline and isoleucine were observed in biofilm 2. Based on general associations, the SUVA of biofilm 2 correlated well with chloroform (CF) (r = 0.80). Generally, in both biofilms, tryptophan-like substances were negatively correlated with DBP while humic acid-like substances correlated positively, but with low indexes (r = 0.3-0.6). Correlations of data from individual sampling increased the indices (r over 0.8), suggesting a temporal influence of other factors on DBP fp such as inorganics, filtered water and the structural composition of EPS. In biofilm 1, Br-haloacetic acids (Br-HAA), dibromoacetonitrile and bromochloro acetonitrile were inversely associated with arginine and valine, as were di and trichloropropanone to arginine. On the contrary, in biofilm 2, the following amino acids correlated positively with DBP: alanine with Br-HAA, alanine with CF, alanine with N-DBP (chloropicrin, di and tri-chloro acetonitrile), and valine with CF. As this is the first report about the relation between temporal variation of EPS and DBP fp of biofilms in two

  11. Ingested Nitrate, Disinfection By-products, and Kidney Cancer Risk in Older Women.

    Science.gov (United States)

    Jones, Rena R; Weyer, Peter J; DellaValle, Curt T; Robien, Kim; Cantor, Kenneth P; Krasner, Stuart; Beane Freeman, Laura E; Ward, Mary H

    2017-09-01

    N-nitroso compounds formed endogenously after nitrate/nitrite ingestion are animal renal carcinogens. Previous epidemiologic studies of drinking water nitrate did not evaluate other potentially toxic water contaminants, including the suspected renal carcinogen chloroform. In a cohort of postmenopausal women in Iowa (1986-2010), we used historical measurements to estimate long-term average concentrations of nitrate-nitrogen (NO3-N) and disinfection by-products (DBP) in public water supplies. For NO3-N and the regulated DBP (total trihalomethanes [THM] and the sum of five haloacetic acids [HAA5]), we estimated the number of years of exposure above one-half the current maximum contaminant level (>½-MCL NO3-N; >5 mg/L). Dietary intakes were assessed via food frequency questionnaire. We estimated hazard ratios (HRs) and 95% confidence intervals (CIs) with Cox models, and evaluated interactions with factors influencing N-nitroso compound formation. We identified 125 incident kidney cancers among 15,577 women reporting using water from public supplies >10 years. In multivariable models, risk was higher in the 95th percentile of average NO3-N (HRp95vsQ1 = 2.3; CI: 1.2, 4.3; Ptrend = 0.33) and for any years of exposure >½-MCL; adjustment for total THM did not materially change these associations. There were no independent relationships with total THM, individual THMs chloroform and bromodichloromethane, or with haloacetic acids. Dietary analyses yielded associations with high nitrite intake from processed meats but not nitrate or nitrite overall. We found no interactions. Relatively high nitrate levels in public water supplies were associated with increased risk of renal cancer. Our results also suggest that nitrite from processed meat is a renal cancer risk factor.

  12. Fingerprinting the reactive toxicity pathways of 50 drinking water disinfection by-products.

    Science.gov (United States)

    Stalter, Daniel; O'Malley, Elissa; von Gunten, Urs; Escher, Beate I

    2016-03-15

    A set of nine in vitro cellular bioassays indicative of different stages of the cellular toxicity pathway was applied to 50 disinfection by-products (DBPs) to obtain a better understanding of the commonalities and differences in the molecular mechanisms of reactive toxicity of DBPs. An Eschericia coli test battery revealed reactivity towards proteins/peptides for 64% of the compounds. 98% activated the NRf2-mediated oxidative stress response and 68% induced an adaptive stress response to genotoxic effects as indicated by the activation of the tumor suppressor protein p53. All DBPs reactive towards DNA in the E. coli assay and activating p53 also induced oxidative stress, confirming earlier studies that the latter could trigger DBP's carcinogenicity. The energy of the lowest unoccupied molecular orbital ELUMO as reactivity descriptor was linearly correlated with oxidative stress induction for trihalomethanes (r(2)=0.98) and haloacetamides (r(2)=0.58), indicating that potency of these DBPs is connected to electrophilicity. However, the descriptive power was poor for haloacetic acids (HAAs) and haloacetonitriles (r(2) (0.80, indicating that HAAs' potency is connected to both, electrophilicity and speciation. Based on the activation of oxidative stress response and the soft electrophilic character of most tested DBPs we hypothesize that indirect genotoxicity-e.g., through oxidative stress induction and/or enzyme inhibition-is more plausible than direct DNA damage for most investigated DBPs. The results provide not only a mechanistic understanding of the cellular effects of DBPs but the effect concentrations may also serve to evaluate mixture effects of DBPs in water samples. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Environmental and personal determinants of the uptake of disinfection by-products during swimming.

    Science.gov (United States)

    Font-Ribera, Laia; Kogevinas, Manolis; Schmalz, Christina; Zwiener, Christian; Marco, Esther; Grimalt, Joan O; Liu, Jiaqi; Zhang, Xiangru; Mitch, William; Critelli, Rossana; Naccarati, Alessio; Heederik, Dick; Spithoven, Jack; Arjona, Lourdes; de Bont, Jeroen; Gracia-Lavedan, Esther; Villanueva, Cristina M

    2016-08-01

    Trihalomethanes (THMs) in exhaled breath and trichloroacetic acid (TCAA) in urine are internal dose biomarkers of exposure to disinfection by-products (DBPs) in swimming pools. We assessed how these biomarkers reflect the levels of a battery of DBPs in pool water and trichloramine in air, and evaluated personal determinants. A total of 116 adults swam during 40min in a chlorinated indoor pool. We measured chloroform, bromodichloromethane, dibromochloromethane and bromoform in exhaled breath and TCAA in urine before and after swimming, trichloramine in air and several DBPs in water. Personal determinants included sex, age, body mass index (BMI), distance swum, energy expenditure, heart rate and 12 polymorphisms in GSTT1, GSTZ1 and CYP2E1 genes. Median level of exhaled total THMs and creatinine adjusted urine TCAA increased from 0.5 to 14.4µg/m(3) and from 2.5 to 5.8µmol/mol after swimming, respectively. The increase in exhaled brominated THMs was correlated with brominated THMs, haloacetic acids, haloacetonitriles, haloketones, chloramines, total organic carbon and total organic halogen in water and trichloramine in air. Such correlations were not detected for exhaled chloroform, total THMs or urine TCAA. Exhaled THM increased more in men, urine TCAA increased more in women, and both were affected by exercise intensity. Genetic variants were associated with differential increases in exposure biomarkers. Our findings suggest that, although affected by sex, physical activity and polymorphisms in key metabolizing enzymes, brominated THMs in exhaled breath could be used as a non-invasive DBP exposure biomarker in swimming pools with bromide-containing source waters. This warrants confirmation with new studies. Copyright © 2016 Elsevier Inc. All rights reserved.

  14. ANALYTICAL METHODS FOR WATER DISINFECTION BY-PRODUCTS IN FOODS AND BEVERAGES

    Science.gov (United States)

    The determination of exposure to drinking water disinfection byproducts (DBPs) requires an understanding of how drinking waters come into contact with the human through multiple pathways. The most significant pathway is the ingestion of drinking water. However, ingestion can oc...

  15. Drinking-Water Disinfection By-products and Semen Quality: A Cross-Sectional Study in China

    Science.gov (United States)

    Zeng, Qiang; Wang, Yi-Xin; Xie, Shao-Hua; Xu, Liang; Chen, Yong-Zhe; Li, Min; Yue, Jing; Li, Yu-Feng; Liu, Ai-Lin

    2014-01-01

    Background: Exposure to disinfection by-products (DBPs) has been demonstrated to impair male reproductive health in animals, but human evidence is limited and inconsistent. Objective: We examined the association between exposure to drinking-water DBPs and semen quality in a Chinese population. Methods: We recruited 2,009 men seeking semen analysis from the Reproductive Center of Tongji Hospital in Wuhan, China, between April 2011 and May 2012. Each man provided a semen sample and a urine sample. Semen samples were analyzed for sperm concentration, sperm motility, and sperm count. As a biomarker of exposure to drinking-water DBPs, trichloroacetic acid (TCAA) was measured in the urine samples. Results: The mean (median) urinary TCAA concentration was 9.58 (7.97) μg/L (interquartile range, 6.01–10.96 μg/L). Compared with men with urine TCAA in the lowest quartile, increased adjusted odds ratios (ORs) were estimated for below-reference sperm concentration in men with TCAA in the second and fourth quartiles (OR = 1.79; 95% CI: 1.19, 2.69 and OR = 1.51; 95% CI: 0.98, 2.31, respectively), for below-reference sperm motility in men with TCAA in the second and third quartiles (OR = 1.46; 95% CI: 1.12, 1.90 and OR = 1.30; 95% CI: 1.00, 1.70, respectively), and for below-reference sperm count in men with TCAA in the second quartile (OR 1.62; 95% CI: 1.04, 2.55). Nonmonotonic associations with TCAA quartiles were also estimated for semen parameters modeled as continuous outcomes, although significant negative associations were estimated for all quartiles above the reference level for sperm motility. Conclusion: Our findings suggest that exposure to drinking-water DBPs may contribute to decreased semen quality in humans. Citation: Zeng Q, Wang YX, Xie SH, Xu L, Chen YZ, Li M, Yue J, Li YF, Liu AL, Lu WQ. 2014. Drinking-water disinfection by-products and semen quality: a cross-sectional study in China. Environ Health Perspect 122:741–746; http://dx.doi.org/10.1289/ehp

  16. Secondary formation of disinfection by-products by UV treatment of swimming pool water

    Energy Technology Data Exchange (ETDEWEB)

    Spiliotopoulou, Aikaterini [Water ApS, Farum Gydevej 64, 3520 Farum (Denmark); Department of Environmental Engineering, Technical University of Denmark, Miljøvej, Building 113, 2800 Kongens Lyngby (Denmark); Hansen, Kamilla M.S., E-mail: kmsh@env.dtu.dk [Department of Environmental Engineering, Technical University of Denmark, Miljøvej, Building 113, 2800 Kongens Lyngby (Denmark); Andersen, Henrik R. [Department of Environmental Engineering, Technical University of Denmark, Miljøvej, Building 113, 2800 Kongens Lyngby (Denmark)

    2015-07-01

    Formation of disinfection by-products (DBPs) during experimental UV treatment of pool water has previously been reported with little concurrence between laboratory studies, field studies and research groups. In the current study, changes in concentration of seven out of eleven investigated volatile DBPs were observed in experiments using medium pressure UV treatment, with and without chlorine and after post-UV chlorination. Results showed that post-UV chlorine consumption increased, dose-dependently, with UV treatment dose. A clear absence of trihalomethane formation by UV and UV with chlorine was observed, while small yet statistically significant increases in dichloroacetonitrile and dichloropropanone concentrations were detected. Results indicate that post-UV chlorination clearly induced secondary formation of several DBPs. However, the formation of total trihalomethanes was no greater than what could be replicated by performing the DBP formation assay with higher chlorine concentrations to simulate extended chlorination. Post-UV chlorination of water from a swimming pool that continuously uses UV treatment to control combined chlorine could not induce secondary formation for most DBPs. Concurrence for induction of trihalomethanes was identified between post-UV chlorination treatments and simulated extended chlorination time treatment. Trihalomethanes could not be induced by UV treatment of water from a continuously UV treated pool. This indicates that literature reports of experimentally induced trihalomethane formation by UV may be a result of kinetic increase in formation by UV. However, this does not imply that higher trihalomethane concentrations would occur in pools that apply continuous UV treatment. The bromine fraction of halogens in formed trihalomethanes increased with UV dose. This indicates that UV removes bromine atoms from larger molecules that participate in trihalomethane production during post-UV chlorination. Additionally, no significant

  17. Ingested nitrate and nitrite, disinfection by-products, and pancreatic cancer risk in postmenopausal women.

    Science.gov (United States)

    Quist, Arbor J L; Inoue-Choi, Maki; Weyer, Peter J; Anderson, Kristin E; Cantor, Kenneth P; Krasner, Stuart; Freeman, Laura E Beane; Ward, Mary H; Jones, Rena R

    2018-01-15

    Nitrate and nitrite are precursors of N-nitroso compounds (NOC), probable human carcinogens that cause pancreatic tumors in animals. Disinfection by-products (DBP) exposures have also been linked with digestive system cancers, but few studies have evaluated relationships with pancreatic cancer. We investigated the association of pancreatic cancer with these drinking water contaminants and dietary nitrate/nitrite in a cohort of postmenopausal women in Iowa (1986-2011). We used historical monitoring and treatment data to estimate levels of long-term average nitrate and total trihalomethanes (TTHM; the sum of the most prevalent DBP class) and the duration exceeding one-half the maximum contaminant level (>½ MCL; 5 mg/L nitrate-nitrogen, 40 µg/L TTHM) among participants on public water supplies (PWS) >10 years. We estimated dietary nitrate and nitrite intakes using a food frequency questionnaire. We computed hazard ratios (HR) and 95% confidence intervals (CI) using Cox regression and evaluated nitrate interactions with smoking and vitamin C intake. We identified 313 cases among 34,242 women, including 152 with >10 years PWS use (N = 15,710). Multivariable models of average nitrate showed no association with pancreatic cancer (HR p95 vs . Q1  = 1.16, 95% CI: 0.51-2.64). Associations with average TTHM levels were also null (HR Q4 vs . Q1  = 0.70, 95% CI:0.42-1.18). We observed no trend with increasing years of exposure to either contaminant at levels >½ MCL. Positive associations were suggested in the highest dietary nitrite intake from processed meat (HR p95 vs . Q1  = 1.66, 95% CI 1.00-2.75;p trend  = 0.05). We found no interactions of nitrate with known modifiers of endogenous NOC formation. Our results suggest that nitrite intake from processed meat may be a risk factor for pancreatic cancer. 2017 UICC.

  18. Assessment of air and water contamination by disinfection by-products at 41 indoor swimming pools.

    Science.gov (United States)

    Tardif, Robert; Catto, Cyril; Haddad, Sami; Simard, Sabrina; Rodriguez, Manuel

    2016-07-01

    This study was aimed at assessing the profiles (occurrence and speciation) of disinfection by-product (DBP) contamination in air and water of a group of 41 public indoor swimming pools in Québec (Canada). The contaminants measured in the water included the traditional DBPs [i.e., four trihalomethanes (THMs), six haloacetic acids (HAAs)] but also several emergent DBPs [i.e., halonitriles, halonitromethanes, haloketones and nitrosodimethylamine (NDMA)]. Those measured in the air comprised THMs and chloramines (CAMs). Overall, extremely variable DBP levels were found from one pool to another (both quantitatively and in terms of speciation). For instance, in water, among the four THMs, chloroform was usually the most abundant compound (37.9±25.7µg/L). Nevertheless, the sum of the three other brominated THMs represented more than 25% of total THMs at almost half the facilities visited (19 cases). In 13 of them, the levels of brominated THMs (66±24.2µg/L) even greatly outweighed the levels of chloroform (15.2±6.31µg/L). Much higher levels of HAAs (294.8±157.6µg/L) were observed, with a consistent preponderance of brominated HAAs in the swimming pools with more brominated THMs. NDMA levels which were measured in a subset of 8 pools ranged between 2.8ng/L and 105ng/L. With respect to air, chloroform was still the most abundant THM globally (119.4±74.2µg/m(3)) but significant levels of brominated THMs were also observed in various cases, particularly in the previously evoked group of 13 swimming pools with preponderant levels of brominated THMs in water. CAM levels (0.23±0.15mg/m(3)) varied highly, ranging from not detected to 0.56mg/m(3). Overall, the levels were generally relatively high compared to current guidelines or reference values from several countries, and they point to a relatively atypical presence of brominated compounds, and to significant levels of emergent DBPs for which health risk is less documented. Copyright © 2016 Elsevier Inc. All rights

  19. Secondary formation of disinfection by-products by UV treatment of swimming pool water

    International Nuclear Information System (INIS)

    Spiliotopoulou, Aikaterini; Hansen, Kamilla M.S.; Andersen, Henrik R.

    2015-01-01

    Formation of disinfection by-products (DBPs) during experimental UV treatment of pool water has previously been reported with little concurrence between laboratory studies, field studies and research groups. In the current study, changes in concentration of seven out of eleven investigated volatile DBPs were observed in experiments using medium pressure UV treatment, with and without chlorine and after post-UV chlorination. Results showed that post-UV chlorine consumption increased, dose-dependently, with UV treatment dose. A clear absence of trihalomethane formation by UV and UV with chlorine was observed, while small yet statistically significant increases in dichloroacetonitrile and dichloropropanone concentrations were detected. Results indicate that post-UV chlorination clearly induced secondary formation of several DBPs. However, the formation of total trihalomethanes was no greater than what could be replicated by performing the DBP formation assay with higher chlorine concentrations to simulate extended chlorination. Post-UV chlorination of water from a swimming pool that continuously uses UV treatment to control combined chlorine could not induce secondary formation for most DBPs. Concurrence for induction of trihalomethanes was identified between post-UV chlorination treatments and simulated extended chlorination time treatment. Trihalomethanes could not be induced by UV treatment of water from a continuously UV treated pool. This indicates that literature reports of experimentally induced trihalomethane formation by UV may be a result of kinetic increase in formation by UV. However, this does not imply that higher trihalomethane concentrations would occur in pools that apply continuous UV treatment. The bromine fraction of halogens in formed trihalomethanes increased with UV dose. This indicates that UV removes bromine atoms from larger molecules that participate in trihalomethane production during post-UV chlorination. Additionally, no significant

  20. A comparison of disinfection by-products formation during sequential or simultaneous disinfection of surface waters with chlorine dioxide and chlor(am)ine.

    Science.gov (United States)

    Shi, Yanwei; Ling, Wencui; Qiang, Zhimin

    2013-01-01

    The effect of chlorine dioxide (ClO2) oxidation on the formation of disinfection by-products (DBPs) during sequential (ClO2 pre-oxidation for 30 min) and simultaneous disinfection processes with free chlorine (FC) or monochloramine (MCA) was investigated. The formation of DBPs from synthetic humic acid (HA) water and three natural surface waters containing low bromide levels (11-27 microg/L) was comparatively examined in the FC-based (single FC, sequential ClO2-FC, and simultaneous ClO2/FC) and MCA-based (single MCA, ClO2-MCA, and ClO2/MCA) disinfection processes. The results showed that much more DBPs were formed from the synthetic HA water than from the three natural surface waters with comparative levels of dissolved organic carbon. In the FC-based processes, ClO2 oxidation could reduce trihalomethanes (THMs) by 27-35% and haloacetic acids (HAAs) by 14-22% in the three natural surface waters, but increased THMs by 19% and HAAs by 31% in the synthetic HA water after an FC contact time of 48 h. In the MCA-based processes, similar trends were observed although DBPs were produced at a much lower level. There was an insignificant difference in DBPs formation between the sequential and simultaneous processes. The presence of a high level of bromide (320 microg/L) remarkably promoted the DBPs formation in the FC-based processes. Therefore, the simultaneous disinfection process of ClO2/MCA is recommended particularly for waters with a high bromide level.

  1. What's in The Pool? A Comprehensive Identification Of Disinfection By-Products and Assessment of Mutagenicity of Chlorinated and Brominated Swimming Pool Water

    Science.gov (United States)

    Swimming pool disinfectants and disinfection by-products (DBPs) have been linked to human health effects, including asthma and bladder cancer, but no studies have provided a comprehensive identification of DBPs in the water and related that to mutagenicity. We performed a compreh...

  2. What's in the pool? A comprehensive identification of disinfection by-products and assessment of mutagenicity of chlorinated and brominated swimming pool water

    NARCIS (Netherlands)

    Richardson, S.D.; Demarini, D.M.; Kogevinas, M.; Fernandez, P.; Marco, E.; Lourencetti, C.; Balleste, C.; Heederik, D.|info:eu-repo/dai/nl/072910542; Meliefste, K.; McKague, A.B.; Marcos, R.; Font-Ribera, L.; Grimalt, J.O.; Villanueva, C.M.

    2010-01-01

    BACKGROUND: Swimming pool disinfectants and disinfection by-products (DBPs) have been linked to human health effects, including asthma and bladder cancer, but no studies have provided a comprehensive identification of DBPs in the water and related that to mutagenicity. OBJECTIVES: We performed a

  3. Formation of Toxic Iodinated Disinfection By-Products from Compounds Used in Medical Imaging

    Science.gov (United States)

    Iodinated X-ray contrast media (ICM) were investigated as a source of iodine in the formation of iodo-trihalomethane (iodo-THM) and iodo-acid disinfection byproducts (DBPs), both of which are highly genotoxic and/or cytotoxic in mammalian cells. ICM are widely used at medical cen...

  4. ANALYTICAL METHODS FOR WATER DISINFECTION BY-PRODUCTS IN FOODS AND BEVERAGES

    Science.gov (United States)

    The determination of exposure to drinking water disinfection byproducts (DBPs) requires an understanding of how drinking water comes in contact with humans through multiple pathways. In order to facilitate the investigation of human exposure to DBPs via foods and beverages, analy...

  5. Nano-silver in drinking water and drinking water sources: stability and influences on disinfection by-product formation.

    Science.gov (United States)

    Tugulea, A-M; Bérubé, D; Giddings, M; Lemieux, F; Hnatiw, J; Priem, J; Avramescu, M-L

    2014-10-01

    Nano-silver is increasingly used in consumer products from washing machines and refrigerators to devices marketed for the disinfection of drinking water or recreational water. The nano-silver in these products may be released, ending up in surface water bodies which may be used as drinking water sources. Little information is available about the stability of the nano-silver in sources of drinking water, its fate during drinking water disinfection processes, and its interaction with disinfection agents and disinfection by-products (DBPs). This study aims to investigate the stability of nano-silver in drinking water sources and in the finished drinking water when chlorine and chloramines are used for disinfection and to observe changes in the composition of DBPs formed when nano-silver is present in the source water. A dispersion of nano-silver particles (10 nm; PVP-coated) was used to spike untreated Ottawa River water, treated Ottawa River water, organic-free water, and a groundwater at concentrations of 5 mg/L. The diluted dispersions were kept under stirred and non-stirred conditions for up to 9 months and analyzed weekly using UV absorption to assess the stability of the nano-silver particles. In a separate experiment, Ottawa River water containing nano-silver particles (at 0.1 and 1 mg/L concentration, respectively) was disinfected by adding sodium hypochlorite (a chlorinating agent) in sufficient amounts to maintain a free chlorine residual of approximately 0.4 mg/L after 24 h. The disinfected drinking water was then quenched with ascorbic acid and analyzed for 34 neutral DBPs (trihalomethanes, haloacetonitriles, haloacetaldehydes, 1,1 dichloro-2-propanone, 1,1,1 trichloro-2-propanone, chloropicrin, and cyanogen chloride). The results were compared to the profile of DBPs obtained under the same conditions in the absence of nano-silver and in the presence of an equivalent concentration of Ag(+) ions (as AgNO3). The stability of the nano-silver dispersions in

  6. Evaluation of associations between lifetime exposure to drinking water disinfection by-products and bladder cancer in dogs.

    Science.gov (United States)

    Backer, Lorraine C; Coss, Angela M; Wolkin, Amy F; Flanders, W Dana; Reif, John S

    2008-06-01

    To assess the risk of bladder cancer in dogs from exposure to drinking water disinfection by-products and determine whether dogs could serve as sentinels for human bladder cancer associated with such exposures. Case-control study. 100 dogs with cancer of the urinary bladder and 100 control dogs. Case and control dogs were frequency-matched by age (within 2 years) and sex. Owners of dogs enrolled provided verbal informed consent and were interviewed by telephone. The telephone questionnaire included a complete residence history for each dog. Each dog's total exposure history to trihalomethanes was reconstructed from its residence history and corresponding drinking water utility company data. No association was detected between increasing years of exposure to chlorinated drinking water and risk of bladder cancer. Dogs with bladder cancer were exposed to higher total trihalomethanes concentrations than control dogs; however, the difference was not significant. Although humans and their dogs live in the same household, the activity patterns of dogs may lead to lower exposures to household tap water. Thus, although exposure to disinfection by-products in tap water may be a risk factor for human bladder cancer, this may not be true for canine bladder cancer at the concentrations at which dogs are exposed.

  7. The impact of iodinated X-ray contrast agents on formation and toxicity of disinfection by-products in drinking water.

    Science.gov (United States)

    Jeong, Clara H; Machek, Edward J; Shakeri, Morteza; Duirk, Stephen E; Ternes, Thomas A; Richardson, Susan D; Wagner, Elizabeth D; Plewa, Michael J

    2017-08-01

    The presence of iodinated X-ray contrast media (ICM) in source waters is of high concern to public health because of their potential to generate highly toxic disinfection by-products (DBPs). The objective of this study was to determine the impact of ICM in source waters and the type of disinfectant on the overall toxicity of DBP mixtures and to determine which ICM and reaction conditions give rise to toxic by-products. Source waters collected from Akron, OH were treated with five different ICMs, including iopamidol, iopromide, iohexol, diatrizoate and iomeprol, with or without chlorine or chloramine disinfection. The reaction product mixtures were concentrated with XAD resins and the mammalian cell cytotoxicity and genotoxicity of the reaction mixture concentrates was measured. Water containing iopamidol generated an enhanced level of mammalian cell cytotoxicity and genotoxicity after disinfection. While chlorine disinfection with iopamidol resulted in the highest cytotoxicity overall, the relative iopamidol-mediated increase in toxicity was greater when chloramine was used as the disinfectant compared with chlorine. Four other ICMs (iopromide, iohexol, diatrizoate, and iomeprol) expressed some cytotoxicity over the control without any disinfection, and induced higher cytotoxicity when chlorinated. Only iohexol enhanced genotoxicity compared to the chlorinated source water. Copyright © 2017. Published by Elsevier B.V.

  8. Evaluating Evidence for Association of Human Bladder Cancer with Drinking-Water Chlorination Disinfection By-Products.

    Science.gov (United States)

    Hrudey, Steve E; Backer, Lorraine C; Humpage, Andrew R; Krasner, Stuart W; Michaud, Dominique S; Moore, Lee E; Singer, Philip C; Stanford, Benjamin D

    2015-01-01

    Exposure to chlorination disinfection by-products (CxDBPs) is prevalent in populations using chlorination-based methods to disinfect public water supplies. Multifaceted research has been directed for decades to identify, characterize, and understand the toxicology of these compounds, control and minimize their formation, and conduct epidemiologic studies related to exposure. Urinary bladder cancer has been the health risk most consistently associated with CxDBPs in epidemiologic studies. An international workshop was held to (1) discuss the qualitative strengths and limitations that inform the association between bladder cancer and CxDBPs in the context of possible causation, (2) identify knowledge gaps for this topic in relation to chlorine/chloramine-based disinfection practice(s) in the United States, and (3) assess the evidence for informing risk management. Epidemiological evidence linking exposures to CxDBPs in drinking water to human bladder cancer risk provides insight into causality. However, because of imprecise, inaccurate, or incomplete estimation of CxDBPs levels in epidemiologic studies, translation from hazard identification directly to risk management and regulatory policy for CxDBPs can be challenging. Quantitative risk estimates derived from toxicological risk assessment for CxDBPs currently cannot be reconciled with those from epidemiologic studies, notwithstanding the complexities involved, making regulatory interpretation difficult. Evidence presented here has both strengths and limitations that require additional studies to resolve and improve the understanding of exposure response relationships. Replication of epidemiologic findings in independent populations with further elaboration of exposure assessment is needed to strengthen the knowledge base needed to better inform effective regulatory approaches.

  9. Evaluating Evidence for Association of Human Bladder Cancer with Drinking-Water Chlorination Disinfection By-Products

    Science.gov (United States)

    Hrudey, Steve E.; Backer, Lorraine C.; Humpage, Andrew R.; Krasner, Stuart W.; Michaud, Dominique S.; Moore, Lee E.; Singer, Philip C.; Stanford, Benjamin D.

    2015-01-01

    Exposure to chlorination disinfection by-products (CxDBPs) is prevalent in populations using chlorination-based methods to disinfect public water supplies. Multifaceted research has been directed for decades to identify, characterize, and understand the toxicology of these compounds, control and minimize their formation, and conduct epidemiologic studies related to exposure. Urinary bladder cancer has been the health risk most consistently associated with CxDBPs in epidemiologic studies. An international workshop was held to (1) discuss the qualitative strengths and limitations that inform the association between bladder cancer and CxDBPs in the context of possible causation, (2) identify knowledge gaps for this topic in relation to chlorine/chloramine-based disinfection practice(s) in the United States, and (3) assess the evidence for informing risk management. Epidemiological evidence linking exposures to CxDBPs in drinking water to human bladder cancer risk provides insight into causality. However, because of imprecise, inaccurate, or incomplete estimation of CxDBPs levels in epidemiologic studies, translation from hazard identification directly to risk management and regulatory policy for CxDBPs can be challenging. Quantitative risk estimates derived from toxicological risk assessment for CxDBPs currently cannot be reconciled with those from epidemiologic studies, notwithstanding the complexities involved, making regulatory interpretation difficult. Evidence presented here has both strengths and limitations that require additional studies to resolve and improve the understanding of exposure response relationships. Replication of epidemiologic findings in independent populations with further elaboration of exposure assessment is needed to strengthen the knowledge base needed to better inform effective regulatory approaches. PMID:26309063

  10. Drinking Water Disinfection By-products, Genetic Polymorphisms, and Birth Outcomes in a European Mother-Child Cohort Study.

    Science.gov (United States)

    Kogevinas, Manolis; Bustamante, Mariona; Gracia-Lavedán, Esther; Ballester, Ferran; Cordier, Sylvaine; Costet, Nathalie; Espinosa, Ana; Grazuleviciene, Regina; Danileviciute, Asta; Ibarluzea, Jesus; Karadanelli, Maria; Krasner, Stuart; Patelarou, Evridiki; Stephanou, Euripides; Tardón, Adonina; Toledano, Mireille B; Wright, John; Villanueva, Cristina M; Nieuwenhuijsen, Mark

    2016-11-01

    We examined the association between exposure during pregnancy to trihalomethanes, the most common water disinfection by-products, and birth outcomes in a European cohort study (Health Impacts of Long-Term Exposure to Disinfection By-Products in Drinking Water). We took into account exposure through different water uses, measures of water toxicity, and genetic susceptibility. We enrolled 14,005 mothers (2002-2010) and their children from France, Greece, Lithuania, Spain, and the UK. Information on lifestyle- and water-related activities was recorded. We ascertained residential concentrations of trihalomethanes through regulatory records and ad hoc sampling campaigns and estimated route-specific trihalomethane uptake by trimester and for whole pregnancy. We examined single nucleotide polymorphisms and copy number variants in disinfection by-product metabolizing genes in nested case-control studies. Average levels of trihalomethanes ranged from around 10 μg/L to above the regulatory limits in the EU of 100 μg/L between centers. There was no association between birth weight and total trihalomethane exposure during pregnancy (β = 2.2 g in birth weight per 10 μg/L of trihalomethane, 95% confidence interval = 3.3, 7.6). Birth weight was not associated with exposure through different routes or with specific trihalomethane species. Exposure to trihalomethanes was not associated with low birth weight (odds ratio [OR] per 10 μg/L = 1.02, 95% confidence interval = 0.95, 1.10), small-for-gestational age (OR = 0.99, 0.94, 1.03) and preterm births (OR = 0.98, 0.9, 1.05). We found no gene-environment interactions for mother or child polymorphisms in relation to preterm birth or small-for-gestational age. In this large European study, we found no association between birth outcomes and trihalomethane exposures during pregnancy in the total population or in potentially genetically susceptible subgroups. (See video abstract at http://links.lww.com/EDE/B104.).

  11. Models for estimation of the presence of non-regulated disinfection by-products in small drinking water systems.

    Science.gov (United States)

    Guilherme, Stéphanie; Rodriguez, Manuel J

    2017-10-23

    Among all the organic disinfection by-products (DBPs), only trihalomethanes (THMs) and haloacetic acids (HAAs) are regulated in drinking water, while most DBPs are not. Very little information exists on the occurrence of non-regulated DBPs, particularly in small water systems (SWS). Paradoxically, SWS are more vulnerable to DBPs because of a low capacity to implement adequate treatment technologies to remove DBP precursors. Since DBP analyses are expensive, usually SWS have difficulties to implement a rigorous characterization of these contaminants. The purpose of this study was to estimate non-regulated DBP levels in SWS from easy measurements of relevant parameters regularly monitored. Since no information on non-regulated DBPs in SWS was available, a sampling program was carried out in 25 SWS in two provinces of Canada. Five DBP families were investigated: THMs, HAAs, haloacetonitriles (HANs), halonitromethanes (HNMs), and haloketones (HKs). Multivariate linear mixed regression models were developed to estimate HAN, HK, and HNM levels from water quality characteristics in the water treatment plant, concentrations of regulated DBPs, and residual disinfectant levels. The models obtained have a good explanatory capacity since R 2 varies from 0.77 to 0.91 according to compounds and conditions for application (season and type of treatment). Model validation with an independent database suggested their ability for generalization in similar SWS in North America.

  12. The alkaline comet assay used in evaluation of genotoxic damage of drinking water disinfection by-products (bromoform and chloroform

    Directory of Open Access Journals (Sweden)

    Messaouda Khallef

    2015-06-01

    Full Text Available The alkaline comet assay (pH 12.3 is a useful method for monitoring genotoxic effects of environmental pollutants in the root nuclei of Allium cepa and various plants; it allows the detection of single- and double-strand breaks, incomplete excision-repair sites and cross-links. It has been introduced to detect even small changes in DNA structure. It is a technically simple, highly sensitive, fast and economic test which detects in vitro and in vivo genotoxicity (DNA integrity and packing mode in any cell types examined, and requires just a few cells for its execution (Liman et al., 2011; Yıldız et al., 2009. Chloroform and bromoform are the most important trihalomethanes found in drinking water. Different concentrations of bromoform (25, 50, 75and 100µg/ml and chloroform (25, 50, 100 and 200 µg/ml were introduced to onion tuber roots. Distilled water was used as a negative control and methyl methansulfonate (MMS-10 µg/ml as positive control. All obtained data were subjected to statistical analyses by using SPSS 15.0 for Windows software. For comparison purposes, Duncan multiple range tests using one-way analysis of variance (ANOVA were employed and p<0.05 was accepted as the test of significance. Comet assay results showed that DNA damage was significant at p <0.05 for the different concentrations of chloroform and bromoform compared to the negative control which has a damage rate equal to 3.5 ± 0.7 and the positive control which has damage rate equal to 13.5 ± 2.12. The exposure of root tip cells to these disinfection by-products increases DNA damage. All concentrations examined in this study of bromoform and chloroform cause significant harm, which could be due to DNA damage induced by oxidative stress. The measurement of DNA damage in the nuclei of higher plant tissues is a new area of study with SCGE. This assay could be incorporated into in situ monitoring of atmosphere, water and soil: the comet assay allows a fast detection without

  13. MODERATING INFLUENCE OF THE DRINKING WATER DISINFECTION BY-PRODUCT DIBROMOACETIC ACID ON A DITHIOCARBAMATE-INDUCED SUPPRESSION OF THE LUTEINIZING HORMONE SURGE IN FEMALE RATS.

    Science.gov (United States)

    The disinfection by-product dibromoacetic acid (DBA) has been found in female rats to increase circulating concentrations of both estradiol (E2) and estrone (E1). This effect is apparently due, at least in part, to a suppression in hepatic catabolism. The present study investigat...

  14. Determination of the minor disinfection by-products formed in the water plant of Sant Joan Despi (Barcelona, Spain); Determinacion de los subproductos de desinfeccion minoritarios formados en la planta de Sant Joan Despi (Barcelona)

    Energy Technology Data Exchange (ETDEWEB)

    Cancho, B.; Galceran, M.T. [Universitat de Barcelona (Spain); Ventura, F. [AGBAR. Societat General d` Aigues de Barcelona, S.A. (Spain)

    1997-09-01

    Chlorine is widely used in drinking water disinfection due to be a powerful and not expense disinfection. Although the benefits of disinfection, the formation of stable disinfection by-products of the health concern, is the result of the interaction of aqueous chlorine with natural organic matter presents in water. Disinfection by-products generated in major concentration are trihalomethane and haloacetic acids. Disinfection by-products generated in minor concentration are haloacetonitriles, haloketones,chloral hydrate and chloropicrin and some new groups such as cyanogen halides and trihaloacetaldydes. In this work two analytical methods.: headspace/gas chromatography/electron capture detector and liquid-liquid microextraction/gas chromatography/electron capture detector are studied and compared to determine the minor by-products and to establish finally, a systematic control of them in the different stages of the Water Treatment Plant of San Joan Despi (Barcelona, Spain). (Author) 12 refs.

  15. Acute toxicity of dichloroacetonitrile (DCAN), a typical nitrogenous disinfection by-product (N-DBP), on zebrafish (Danio rerio).

    Science.gov (United States)

    Lin, Tao; Zhou, Dongju; Dong, Jian; Jiang, Fuchun; Chen, Wei

    2016-11-01

    Dichloroacetonitrile (DCAN) is a typical nitrogenous disinfection by-product (N-DBP) and its toxicity on aquatic animals is investigated for the first time. The present study was designed to investigate the potential adverse effects of DCAN on zebrafish. DCAN could induce developmental toxicity to zebrafish embryos. A significant decrease in hatchability and an increase in malformation and mortality occurred when DCAN concentration was above 100µg/L. Heart function alteration and neuronal function disturbance occurred at concentration higher than 500 and 100µg/L, respectively. Further, DCAN was easily accumulated in adult zebrafish. The rank order of declining bioconcentration factor (BCF) was liver (1240-1670)> gill (1210-1430)> muscle (644-877). DCAN caused acute metabolism damage to adult zebrafish especially at 8 days exposure, at which time the "Integrated Biomarker Response" (IBR) index value reached 798 at 1mg/L DCAN dose. Acute DNA damage was induced to adult zebrafish by DCAN even at 10µg/L dose. Copyright © 2016 Elsevier Inc. All rights reserved.

  16. Pyruvate remediation of cell stress and genotoxicity induced by haloacetic acid drinking water disinfection by-products.

    Science.gov (United States)

    Dad, Azra; Jeong, Clara H; Pals, Justin A; Wagner, Elizabeth D; Plewa, Michael J

    2013-10-01

    Monohaloacetic acids (monoHAAs) are a major class of drinking water disinfection by-products (DBPs) and are cytotoxic, genotoxic, mutagenic, and teratogenic. We propose a model of toxic action based on monoHAA-mediated inhibition of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) as a target cytosolic enzyme. This model predicts that GAPDH inhibition by the monoHAAs will lead to a severe reduction of cellular ATP levels and repress the generation of pyruvate. A loss of pyruvate will lead to mitochondrial stress and genomic DNA damage. We found a concentration-dependent reduction of ATP in Chinese hamster ovary cells after monoHAA treatment. ATP reduction per pmol monoHAA followed the pattern of iodoacetic acid (IAA) > bromoacetic acid (BAA) > chloroacetic acid (CAA), which is the pattern of potency observed with many toxicological endpoints. Exogenous supplementation with pyruvate enhanced ATP levels and attenuated monoHAA-induced genomic DNA damage as measured with single cell gel electrophoresis. These data were highly correlated with the SN 2 alkylating potentials of the monoHAAs and with the induction of toxicity. The results from this study strongly support the hypothesis that GAPDH inhibition and the possible subsequent generation of reactive oxygen species is linked with the cytotoxicity, genotoxicity, teratogenicity, and neurotoxicity of these DBPs. Copyright © 2013 Wiley Periodicals, Inc.

  17. Removal of soluble microbial products as the precursors of disinfection by-products in drinking water supplies.

    Science.gov (United States)

    Liu, Jin-Lin; Li, Xiao-Yan

    2015-01-01

    Water pollution worsens the problem of disinfection by-products (DBPs) in drinking water supply. Biodegradation of wastewater organics produces soluble microbial products (SMPs), which can be important DBP precursors. In this laboratory study, a number of enhanced water treatment methods for DBP control, including enhanced coagulation, ozonation, and activated carbon adsorption, were evaluated for their effectiveness in treating SMP-containing water for the DBP reduction purpose. The results show that enhanced coagulation with alum could remove SMPs only marginally and decrease the DBP formation potential (DBPFP) of the water by less than 20%. Although ozone could cause destruction of SMPs in water, the overall DBPFP of the water did not decrease but increased after ozonation. In contrast, adsorption by granular activated carbon could remove the SMP organics from water by more than 60% and reduce the DBPFP by more than 70%. It is apparent that enhanced coagulation and ozonation are not suitable for the removal of SMPs as DBP precursors from polluted water, although enhanced coagulation has been commonly used to reduce the DBP formation caused by natural organic matter. In comparison, activated carbon adsorption is shown as a more effective means to remove the SMP content from water and hence to control the wastewater-derived DBP problem in water supply.

  18. Effect of medium-pressure UV-lamp treatment on disinfection by-products in chlorinated seawater swimming pool waters.

    Science.gov (United States)

    Cheema, Waqas A; Manasfi, Tarek; Kaarsholm, Kamilla M S; Andersen, Henrik R; Boudenne, Jean-Luc

    2017-12-01

    Several brominated disinfection by-products (DBPs) are formed in chlorinated seawater pools, due to the high concentration of bromide in seawater. UV irradiation is increasingly employed in freshwater pools, because UV treatment photodegrades harmful chloramines. However, in freshwater pools it has been reported that post-UV chlorination promotes the formation of other DBPs. To date, UV-based processes have not been investigated for DBPs in seawater pools. In this study, the effects of UV, followed by chlorination, on the concentration of three groups of DBPs were investigated in laboratory batch experiments using a medium-pressure UV lamp. Chlorine consumption increased following post-UV chlorination, most likely because UV irradiation degraded organic matter in the pool samples to more chlorine-reactive organic matter. Haloacetic acid (HAA) concentrations decreased significantly, due to photo-degradation, but the concentrations of trihalomethanes (THMs) and haloacetonitriles (HANs) increased with post-UV chlorination. Bromine incorporation in HAAs was significantly higher in the control samples chlorinated without UV irradiation but decreased significantly with UV treatment. Bromine incorporation was promoted in THM and HAN after UV and chlorine treatment. Overall, the accumulated bromine incorporation level in DBPs remained essentially unchanged in comparison with the control samples. Toxicity estimates increased with single-dose UV and chlorination, mainly due to increased HAN concentrations. However, brominated HANs are known in the literature to degrade following further UV treatment. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. The Effect of Different Boiling and Filtering Devices on the Concentration of Disinfection By-Products in Tap Water

    Directory of Open Access Journals (Sweden)

    Glòria Carrasco-Turigas

    2013-01-01

    Full Text Available Disinfection by-products (DBPs are ubiquitous contaminants in tap drinking water with the potential to produce adverse health effects. Filtering and boiling tap water can lead to changes in the DBP concentrations and modify the exposure through ingestion. Changes in the concentration of 4 individual trihalomethanes (THM4 (chloroform (TCM, bromodichloromethane (BDCM, dibromochloromethane (DBCM, and bromoform (TBM, MX, and bromate were tested when boiling and filtering high bromine-containing tap water from Barcelona. For filtering, we used a pitcher-type filter and a household reverse osmosis filter; for boiling, an electric kettle, a saucepan, and a microwave were used. Samples were taken before and after each treatment to determine the change in the DBP concentration. pH, conductivity, and free/total chlorine were also measured. A large decrease of THM4 (from 48% to 97% and MX concentrations was observed for all experiments. Bromine-containing trihalomethanes were mostly eliminated when filtering while chloroform when boiling. There was a large decrease in the concentration of bromate with reverse osmosis, but there was a little effect in the other experiments. These findings suggest that the exposure to THM4 and MX through ingestion is reduced when using these household appliances, while the decrease of bromate is device dependent. This needs to be considered in the exposure assessment of the epidemiological studies.

  20. Enhanced coagulation with powdered activated carbon or MIEX secondary treatment: a comparison of disinfection by-product formation and precursor removal.

    Science.gov (United States)

    Watson, Kalinda; Farré, Maria José; Knight, Nicole

    2015-01-01

    The removal of both organic and inorganic disinfection by-product (DBP) precursors prior to disinfection is important in mitigating DBP formation, with halide removal being particularly important in salinity-impacted water sources. A matrix of waters of variable alkalinity, halide concentration and dissolved organic carbon (DOC) concentration were treated with enhanced coagulation (EC) followed by anion exchange (MIEX resin) or powdered activated carbon (PAC) and the subsequent disinfection by-product formation potentials (DBP-FPs) assessed and compared to DBP-FPs for untreated samples. Halide and DOC removal were also monitored for both treatment processes. Bromide and iodide adsorption by MIEX treatment ranged from 0 to 53% and 4-78%, respectively. As expected, EC and PAC treatments did not remove halides. DOC removal by EC/PAC was 70 ± 10%, while EC/MIEX enabled a DOC removal of 66 ± 12%. Despite the halide removals achieved by MIEX, increases in brominated disinfection by-product (Br-DBP) formation were observed relative to untreated samples, when favourable Br:DOC ratios were created by the treatment. However, the increases in formation were less than what was observed for the EC/PAC treated waters, which caused large increases in Br-DBP formation when high Br-DBP-forming water quality conditions occurred. The formation potential of fully chlorinated DBPs decreased after treatment in all cases.

  1. Assessing the human health impacts of exposure to disinfection by-products--a critical review of concepts and methods.

    Science.gov (United States)

    Grellier, James; Rushton, Lesley; Briggs, David J; Nieuwenhuijsen, Mark J

    2015-05-01

    Understanding the public health implications of chemical contamination of drinking water is important for societies and their decision-makers. The possible population health impacts associated with exposure to disinfection by-products (DBPs) are of particular interest due to their potential carcinogenicity and their widespread occurrence as a result of treatments employed to control waterborne infectious disease. We searched the literature for studies that have attempted quantitatively to assess population health impacts and health risks associated with exposure to DBPs in drinking water. We summarised and evaluated these assessments in terms of their objectives, methods, treatment of uncertainties, and interpretation and communication of results. In total we identified 40 studies matching our search criteria. The vast majority of studies presented estimates of generic cancer and non-cancer risks based on toxicological data and methods that were designed with regulatory, health-protective purposes in mind, and therefore presented imprecise and biased estimates of health impacts. Many studies insufficiently addressed the numerous challenges to DBP risk assessment, failing to evaluate the evidence for a causal relationship, not appropriately addressing the complex nature of DBP occurrence as a mixture of chemicals, not adequately characterising exposure in space and time, not defining specific health outcomes, not accounting for characteristics of target populations, and not balancing potential risks of DBPs against the health benefits related with drinking water disinfection. Uncertainties were often poorly explained or insufficiently accounted for, and important limitations of data and methods frequently not discussed. Grave conceptual and methodological limitations in study design, as well as erroneous use of available dose-response data, seriously impede the extent to which many of these assessments contribute to understanding the public health implications of

  2. Bioanalytical assessment of adaptive stress responses in drinking water: A predictive tool to differentiate between micropollutants and disinfection by-products.

    Science.gov (United States)

    Hebert, Armelle; Feliers, Cedric; Lecarpentier, Caroline; Neale, Peta A; Schlichting, Rita; Thibert, Sylvie; Escher, Beate I

    2018-04-01

    Drinking water can contain low levels of micropollutants, as well as disinfection by-products (DBPs) that form from the reaction of disinfectants with organic and inorganic matter in water. Due to the complex mixture of trace chemicals in drinking water, targeted chemical analysis alone is not sufficient for monitoring. The current study aimed to apply in vitro bioassays indicative of adaptive stress responses to monitor the toxicological profiles and the formation of DBPs in three drinking water distribution systems in France. Bioanalysis was complemented with chemical analysis of forty DBPs. All water samples were active in the oxidative stress response assay, but only after considerable sample enrichment. As both micropollutants in source water and DBPs formed during treatment can contribute to the effect, the bioanalytical equivalent concentration (BEQ) approach was applied for the first time to determine the contribution of DBPs, with DBPs found to contribute between 17 and 58% of the oxidative stress response. Further, the BEQ approach was also used to assess the contribution of volatile DBPs to the observed effect, with detected volatile DBPs found to have only a minor contribution as compared to the measured effects of the non-volatile chemicals enriched by solid-phase extraction. The observed effects in the distribution systems were below any level of concern, quantifiable only at high enrichment and not different from bottled mineral water. Integrating bioanalytical tools and the BEQ mixture model for monitoring drinking water quality is an additional assurance that chemical monitoring is not overlooking any unknown chemicals or transformation products and can help to ensure chemically safe drinking water. Copyright © 2017. Published by Elsevier Ltd.

  3. Algal toxicity of the alternative disinfectants performic acid (PFA), peracetic acid (PAA), chlorine dioxide (ClO2) and their by-products hydrogen peroxide (H2O2) and chlorite (ClO2-)

    DEFF Research Database (Denmark)

    Chhetri, Ravi Kumar; Baun, Anders; Andersen, Henrik Rasmus

    2017-01-01

    Environmental effect evaluation of disinfection of combined sewer overflow events with alternative chemical disinfectants requires that the environmental toxicity of the disinfectants and the main by-products of their use are known. Many disinfectants degrade quickly in water which should......: performic acid (PFA), peracetic acid (PAA) and chlorine dioxide (ClO2) as well as two by-products of their use: hydrogen peroxide (H2O2) and chlorite. All of the five chemicals investigated showed clear toxicity to the algae with well-defined dose response curves. The EC50 values ranged from 0.16 to 2.9 mg...

  4. Spatial variations in the occurrence of potentially genotoxic disinfection by-products in drinking water distribution systems in China.

    Science.gov (United States)

    Li, Chunmei; Wang, Donghong; Xu, Xiong; Xu, Meijia; Wang, Zijian

    2017-12-01

    We investigated the occurrence of disinfection by-products (DBPs) with genotoxic potential in plant effluent and distribution water samples from four drinking water treatment plants in two Chinese cities using comprehensive two-dimensional gas chromatography-quadrupole mass spectrometry. We tested the samples for 37 DBPs with genotoxic potential, which we had previously identified and prioritized in water under controlled laboratory conditions. Thirty of these DBPs were found in the water samples at detection frequencies of between 10% and 100%, and at concentrations between 3.90 and 1.77 × 10 3  ng/L. Of the DBPs detected, the concentrations of 1,1,1-trichloropropan-2-one were highest, and ranged from 299 to 1.77 × 10 3  ng/L with an average of 796 ng/L. The concentrations of 6-chloro-2-N-propan-2-yl-1,3,5-triazine-2,4-diamine and 2,6-ditert-butylcyclohexa-2,5-diene-1,4-dione were also much higher, and ranged from 107 to 721 ng/L, and from 152 to 504 ng/L, respectively. Concentrations of 1,1,1-trichloropropan-2-one, 2-chloro-1-phenylethanone, 2,2-dichloro-1-phenylethanone and 6-chloro-2-N-propan-2-yl-1,3,5-triazine-2,4-diamine were highest at or near the treatment plants and decreased with increasing distance from the plants. Patterns in the concentrations of benzaldehyde, 2-phenylpropan-2-ol, and 1-methylnaphthalene differed between plants. The levels of DBPs such as 4-ethylbenzaldehyde, (E)-non-2-enal, and 1-phenylethanone were relatively constant within the distribution systems, even at the furthest sampling points (20 km drinking water. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Seasonal evaluation of the presence of 46 disinfection by-products throughout a drinking water treatment plant

    International Nuclear Information System (INIS)

    Serrano, Maria; Montesinos, Isabel; Cardador, M.J.; Silva, Manuel; Gallego, Mercedes

    2015-01-01

    In this work, we studied a total of 46 regulated and non-regulated disinfection by-products (DBPs) including 10 trihalomethanes (THMs), 13 haloacetic acids (HAAs), 6 halonitromethanes (HNMs), 6 haloacetonitriles (HANs) and 11 aldehydes at different points in a drinking water treatment plant (DWTP) and its distribution network. Determining an increased number of compounds and using accurate, sensitive analytical methodologies for new DBPs can be useful to overcome some challenges encountered in the comprehensive assessment of the quality and safety of drinking water. This paper provides a detailed picture of the spatial and seasonal variability of DBP concentrations from raw water to distribution network. Samples were collected on a monthly basis at seven different points in the four seasons of a year to acquire robust data for DBPs and supplementary quality-related water parameters. Only 5 aldehydes and 2 HAAs were found in raw water. Chlorine dioxide caused the formation of 3 new aldehydes (benzaldehyde included), 5 HAAs and chloroform. The concentrations of DBPs present in raw water were up to 6 times higher in the warmer seasons (spring and summer). The sedimentation process further increased their concentrations and caused the formation of three new ones. Sand filtration substantially removed aldehydes and HAAs (15–50%), but increased the levels of THMs, HNMs and HANs by up to 70%. Chloramination raised the levels of 8 aldehydes and 7 HAAs; also, it caused the formation of monoiodoacetic acid, dibromochloromethane, dichloroiodomethane and bromochloroacetonitrile. Therefore, this treatment increases the levels of existing DBPs and leads to the formation of new ones to a greater extent than does chlorine dioxide. Except for 5 aldehydes, the 23 DBPs encountered at the DWTP exit were found at increased concentrations in the warmer seasons (HAAs by about 50% and THMs by 350%). - Highlights: • Occurrence of 46 regulated and non-regulated DBPs through a DWTP was

  6. Drinking water disinfection by-products during pregnancy and child neuropsychological development in the INMA Spanish cohort study.

    Science.gov (United States)

    Villanueva, Cristina M; Gracia-Lavedan, Esther; Julvez, Jordi; Santa-Marina, Loreto; Lertxundi, Nerea; Ibarluzea, Jesús; Llop, Sabrina; Ballester, Ferran; Fernández-Somoano, Ana; Tardón, Adonina; Vrijheid, Martine; Guxens, Mònica; Sunyer, Jordi

    2018-01-01

    Disinfection by-products (DBPs) constitute a complex mixture of prevalent chemicals in drinking water and there is evidence of neurotoxicity for some of them. We evaluated the association between estimates of DBP exposure during pregnancy and child neuropsychological outcomes at 1 and 4-5years of age. We conducted a population-based mother-child cohort study in Spain with recruitment at first trimester of gestation (INMA Project, 2003-2008). Neuropsychological development was measured at 1year of age using the Bayley Scales of Infant Development and at 4-5years with the McCarthy Scales of Children's Abilities. Modeled tap water concentrations of trihalomethanes (THM) were combined with personal ingestion, showering and bathing habits to estimate exposure as ingestion uptake, all route (showering, bathing, ingestion) uptake (μg/day) and crude levels (μg/l) in the residence. Chloroform, brominated THMs (bromodichloromethane, dibromochloromethane, bromoform) and total THMs (chloroform and brominated THMs) were analysed separately. Nine haloacetic acids levels were available in one of the areas. Linear regression was used to estimate associations in 1855 subjects adjusting for covariables. The median concentration of total THMs, chloroform, brominated THMs, total haloacetic acids, dichloroacetic acid, and trichloroacetic acid were, respectively 30.3μg/L, 9.4μg/L, 11.6μg/L, 10.5μg/L, 2.7μg/L, and 3.1μg/L. The associations between THM exposure and neuropsychological outcomes were null, except for total and brominated THM uptake though all routes and the general cognitive score at 4-5years, with a decrease in -0.54 points (95%CI -1.03, -0.05) and -0.64 (95%CI -1.16, -0.12), respectively, for doubling total and brominated THM uptake. A positive association found between dichloroacetic acid and the mental score at 1year did not persist at 4-5years. Minor associations observed between DBP exposure during gestation and child neuropsychological development at 1year

  7. Seasonal evaluation of the presence of 46 disinfection by-products throughout a drinking water treatment plant

    Energy Technology Data Exchange (ETDEWEB)

    Serrano, Maria; Montesinos, Isabel; Cardador, M.J.; Silva, Manuel; Gallego, Mercedes, E-mail: mercedes.gallego@uco.es

    2015-06-01

    In this work, we studied a total of 46 regulated and non-regulated disinfection by-products (DBPs) including 10 trihalomethanes (THMs), 13 haloacetic acids (HAAs), 6 halonitromethanes (HNMs), 6 haloacetonitriles (HANs) and 11 aldehydes at different points in a drinking water treatment plant (DWTP) and its distribution network. Determining an increased number of compounds and using accurate, sensitive analytical methodologies for new DBPs can be useful to overcome some challenges encountered in the comprehensive assessment of the quality and safety of drinking water. This paper provides a detailed picture of the spatial and seasonal variability of DBP concentrations from raw water to distribution network. Samples were collected on a monthly basis at seven different points in the four seasons of a year to acquire robust data for DBPs and supplementary quality-related water parameters. Only 5 aldehydes and 2 HAAs were found in raw water. Chlorine dioxide caused the formation of 3 new aldehydes (benzaldehyde included), 5 HAAs and chloroform. The concentrations of DBPs present in raw water were up to 6 times higher in the warmer seasons (spring and summer). The sedimentation process further increased their concentrations and caused the formation of three new ones. Sand filtration substantially removed aldehydes and HAAs (15–50%), but increased the levels of THMs, HNMs and HANs by up to 70%. Chloramination raised the levels of 8 aldehydes and 7 HAAs; also, it caused the formation of monoiodoacetic acid, dibromochloromethane, dichloroiodomethane and bromochloroacetonitrile. Therefore, this treatment increases the levels of existing DBPs and leads to the formation of new ones to a greater extent than does chlorine dioxide. Except for 5 aldehydes, the 23 DBPs encountered at the DWTP exit were found at increased concentrations in the warmer seasons (HAAs by about 50% and THMs by 350%). - Highlights: • Occurrence of 46 regulated and non-regulated DBPs through a DWTP was

  8. Prevalence of Ocular, Respiratory and Cutaneous Symptoms in Indoor Swimming Pool Workers and Exposure to Disinfection By-Products (DBPs

    Directory of Open Access Journals (Sweden)

    Guglielmina Fantuzzi

    2010-03-01

    Full Text Available The objective of this cross-sectional study was to investigate the prevalence of self-reported respiratory, ocular and cutaneous symptoms in subjects working at indoor swimming pools and to assess the relationship between frequency of declared symptoms and occupational exposure to disinfection by-products (DBPs. Twenty indoor swimming pools in the Emilia Romagna region of Italy were included in the study. Information about the health status of 133 employees was collected using a self-administered questionnaire. Subjects working at swimming pools claimed to frequently experience the following symptoms: cold (65.4%, sneezing (52.6%, red eyes (48.9% and itchy eyes (44.4%. Only 7.5% claimed to suffer from asthma. Red eyes, runny nose, voice loss and cold symptoms were declared more frequently by pool attendants (lifeguards and trainers when compared with employees working in other areas of the facility (office, cafe, etc.. Pool attendants experienced generally more verrucas, mycosis, eczema and rash than others workers; however, only the difference in the frequency of self-declared mycosis was statistically significant (p = 0.010. Exposure to DBPs was evaluated using both environmental and biological monitoring. Trihalomethanes (THMs, the main DBPs, were evaluated in alveolar air samples collected from subjects. Swimming pool workers experienced different THM exposure levels: lifeguards and trainers showed the highest mean values of THMs in alveolar air samples (28.5 ± 20.2 µg/m3, while subjects working in cafe areas (17.6 ± 12.1 µg/m3, offices (14.4 ± 12.0 µg/m3 and engine rooms (13.6 ± 4.4 µg/m3 showed lower exposure levels. Employees with THM alveolar air values higher than 21 µg/m3 (median value experienced higher risks for red eyes (OR 6.2; 95% CI 2.6–14.9, itchy eyes (OR 3.5; 95% CI 1.5–8.0, dyspnea/asthma (OR 5.1; 95% CI 1.0–27.2 and blocked nose (OR 2.2; 95% CI 1.0–4.7 than subjects with less exposure. This study confirms

  9. A study of the formation of minority chlorination disinfection by-products; Estudio de la formacion de subproductos minoritarios de la desinfeccion con cloro

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez Vidal, F. J.; Ibeas Reoyo, M. v.; Perez Serrano, A.; Orozco Barrenetxea, C.; Gonzalez Delgado, N. [Universidad de Burgos (Spain)

    2001-07-01

    Chlorine has been the traditional choice of chemical for the disinfection in drinking water treatment; however, chlorination of water can lead to the formation of disinfection by-products (DBPs). Tri halomethanes are the most abundant and studied volatile DBPs, but in recent years the study of the minority DBPs is becoming more and more important due to the possible health effects of these compounds and therefore, the need to establish maximum contaminant levels for their presence in public water supplies. In the present work, some of these minority DBPs are evaluated, di chloroacetonitrile (DCAN), chloropicrin or trichloronitromethane (CP) and 1.1,1-tetrachloroethane (TCAC), studying the main parameters influencing their formation: type and concentration of the precursor organic matter, presence of bromide ion, pH and influence of the previous ozonization treatment. (Author) 33 refs.

  10. Modelling of Disinfection by-products formation via UV irradiation of the water from Tajan River (source water for Sari drinking water, Iran

    Directory of Open Access Journals (Sweden)

    Allahbakhsh Javid

    2013-11-01

    Full Text Available Background & Aims of the Study Irradiation with ultraviolet light (UV is used for the disinfection of bacterial contaminants in the production of potable water. The main objective of the study was to investigate and model Disinfection By-Products (DBPs formation due to the UV Irradiation of the Tajan River water under different Irradiation conditions. Materials & Methods:  Water samples were collected throughout September 2011 to August 2013. Transportation of the sample to the laboratory was done on ice in a cooler, and physiochemical analysis was conducted immediately within one day. Dissolved organic carbon (DOC was determined by a TOC analyzer. Irradiation experiments were conducted in a series of 25 mL glass serum bottles with Teflon septa. The present study adopts an orthogonal design. The design involved irradiation with UV at a UV/DOC ratio of 0.5–3.0 and incubating (headspace-free storage for 5–25 sec. A 1 mM phosphate buffer maintained the pH at 6, 7, or 8 respectively, and an incubator maintained the temperature (Temp at 15, 20, or 25 °C respectively. The development of empirical models for DBPs formation used a multivariate regression procedure (stepwise which applied the SPSS System for Windows (Version 16.0. Results:  The results showed that the total DBPs formation ranged between 12.3 and 67.4 mg/l and that control of the levels was primarily due to the reaction time and the dissolved organic carbon level (DOC in the water. Conclusions:  Reaction time and level of DOC concentrations in water exerted a dominant influence on the formation of DBPs during the UV irradiation of water from the Tajan River. The relationships between the measured and predicted values were satisfactory with R 2 values ranging from 0.89 (for Octanal–0.92 (for Formaldehydes. The DOC level in water is the key factor in controlling DBPs formation.

  11. Evaluation of the water disinfection by-product dichloroacetonitrile-induced biochemical, oxidative, histopathological, and mitochondrial functional alterations: Subacute oral toxicity in rats.

    Science.gov (United States)

    Dong, Ying; Li, Fang; Shen, Haijun; Lu, Rongzhu; Yin, Siqi; Yang, Qi; Li, Zhuangfa; Wang, Suhua

    2018-03-01

    Dichloroacetonitrile (DCAN), an emerging nitrogenous disinfection by-product, is more genotoxic and cytotoxic than the currently regulated carbonaceous disinfection by-products such as haloacetic acids. Few mechanistic studies have been conducted on the hepatic and renal toxicities of DCAN. This study examined the clinical biochemical, hematological, histopathological, oxidative, and mitochondrial functional alterations to evaluate the systematic toxicity after subacute oral exposure of 11 or 44 mg/kg/day in rats for 28 days. Body and spleen weights were lower, and organ-to-body weight ratios of the liver and kidney were higher in rats administered 44-mg/kg DCAN than in controls. The activities of serum alanine aminotransferase and alkaline phosphatase, and concentrations of blood serum urea nitrogen and retinol-binding protein were increased in rats administered 44-mg/kg DCAN compared with those of controls, thereby indicating hepatic and renal damage in this group. This was confirmed by histopathological alterations, including hepatic sinus dilation, extensive hemorrhage, vacuolar degeneration in the liver and glomerulus hemorrhage, and renal tubular swelling, in DCAN-exposed rats. Exposure to 44-mg/kg DCAN induced hepatic oxidative damage shown by the significant increase in malonaldehyde levels, a poisonous product of lipid peroxidation. Exposure to 44-mg/kg DCAN significantly increased hepatic glutathione content and mitochondrial bioenergy as noted by the elevation of mitochondrial membrane potential and cytochrome c oxidase activity, which might be attributed to compensatory pathophysiologic responses to DCAN-induced hepatic mitochondrial damage.

  12. Reductions of dissolved organic matter and disinfection by-product precursors in full-scale wastewater treatment plants in winter.

    Science.gov (United States)

    Xue, Shuang; Jin, Wujisiguleng; Zhang, Zhaohong; Liu, Hong

    2017-07-01

    The reductions of dissolved organic matter (DOM) and disinfection byproduct precursors in four full-scale wastewater treatment plants (WWTPs) (Liaoning Province, China) where different biological treatment processes were employed in winter were investigated. The total removal efficiencies of dissolved organic carbon (DOC), ultraviolet light at 254 nm (UV-254), trihalomethane formation potential (THMFP), and haloacetic acid formation potential (HAAFP) were in the range of 70.3-76.0%, 49.6-57.3%, 54.4-65.0%, and 53.7-63.8% in the four WWTPs, respectively. The biological treatment was the predominant process responsible for the removal of DOC, THMFP, and HAAFP in WWTPs. Differences in the reduction of UV-254 were not significant (p > 0.05) among biochemical reaction pool, secondary sedimentation tank, and disinfection tank. Biological aerated filter and suspended carrier activated sludge processes achieved higher DOM removal than the conventional active sludge and anaerobic-anoxic-oxic processes. Hydrophobic neutral and hydrophilic fraction were removed to a higher degree through biological treatment than the other three DOM fractions. HAAFP removal was more efficient than THMFP reduction during biological treatment. During primary treatment, fluorescent materials in secondary sedimentation tanks were preferentially removed, as compared to the bulk DOM. Humic-like fluorescent compounds were not readily eliminated during biological treatment. The fluorescent materials were more susceptible to chlorine than nonfluorescent compounds. Copyright © 2017. Published by Elsevier Ltd.

  13. Disinfection by-product formation during chlor(am)ination of algal organic matters (AOM) extracted from Microcystis aeruginosa: effect of growth phases, AOM and bromide concentration.

    Science.gov (United States)

    Chen, Juxiang; Gao, Naiyun; Li, Lei; Zhu, Mingqiu; Yang, Jing; Lu, Xian; Zhang, Yansen

    2017-03-01

    Algae organic matter (AOM), including extracellular organic matter (EOM) and intracellular organic matter (IOM), has caused a series of problems to the water quality, among which formation of disinfection by-products (DBPs) during subsequent chlor(am)ination process was especially serious and concerned. This study characterized physicochemical properties of the EOM and IOM solution extracted from different growth phases of Microcystis aeruginosa and investigated the corresponding formation potential of DBPs during chlor(am)ination process. Besides, the effects of initial concentration of xEOM, IOM, and Br - on the yields of disinfection by-product formation potential were studied. The results indicated that the specific UV absorbance (SUVA 254 ) values of IOM and EOM (1.09 and 2.66 L/mg m) were considerably lower than that of natural organic matter (NOM) (4.79 L/mg m). Fluorescence dates showed the soluble microbial by-product was dominant in both EOM and IOM, and the tryptophan was the main component of AOM. From the excitation-emission matrix figure of EOM and IOM, we found that the content of the high molecular weight protein substance in IOM was higher than EOM. During chlorination of EOM and IOM, the yields of four kinds of DBPs followed the order trichloroethene (TCM) > 1,1-DCP > dichloride acetonitrile (DCAN) > trichloronitromethane (TCNM), while the order was TCM > DCAN > TCNM > 1,1-DCP during chloramination process. The bromine substitution factor (BSF) value increased with the increasing of the concentration of Br - . When the concentration of Br - was 500 μg/L, the BSF values of chlorination EOM and IOM were 51.1 and 68.4%, respectively. As the concentration of Br - increased, the formation of Cl-DBPs was inhibited and the formation of Br-DBPs was promoted. Graphical abstract ᅟ.

  14. Formation of Emerging Disinfection By-products by Chlorination/Chloramination of Seawater Impacted by Algal Organic Matter

    KAUST Repository

    Nihemaiti, Maolida

    2015-08-31

    The aim of this work was to study the formation of haloacetamides (HAcAms) and other DBPs during chlorination and chloramination of algal organic matter (AlOM). The HAcAms formation potentials of different precursors (amino acids, simulated algal blooms grown in the Red Sea) were evaluated. Experiments with simulated algal blooms were conducted in the presence of bromide ion (synthetic seawater containing 800 μg/L Br−) to assess the formation of brominated analogues of HAcAms in conditions close to the disinfection of real seawater. Chlorination produced more HAcAms than chloramination from real algae (Synecococcus sp.), thus indicating that the nitrogen of HAcAms comes predominantly from DON through the decarboxylation of amino acids rather than from NH2Cl. Dibrominated species of DBPs (i.e., DBAcAm, DBAA and DBAN) were the dominant species formed by both chlorination and chloramination of algal bloom samples. Chloramination of the amino acid asparagine produced an important amount of DCAcAm as compared to chlorination, indicating the existence of a specific reaction pathway.

  15. Formation of Emerging Disinfection By-products by Chlorination/Chloramination of Seawater Impacted by Algal Organic Matter

    KAUST Repository

    Nihemaiti, Maolida; Le Roux, Julien; Croue, Jean-Philippe

    2015-01-01

    The aim of this work was to study the formation of haloacetamides (HAcAms) and other DBPs during chlorination and chloramination of algal organic matter (AlOM). The HAcAms formation potentials of different precursors (amino acids, simulated algal blooms grown in the Red Sea) were evaluated. Experiments with simulated algal blooms were conducted in the presence of bromide ion (synthetic seawater containing 800 μg/L Br−) to assess the formation of brominated analogues of HAcAms in conditions close to the disinfection of real seawater. Chlorination produced more HAcAms than chloramination from real algae (Synecococcus sp.), thus indicating that the nitrogen of HAcAms comes predominantly from DON through the decarboxylation of amino acids rather than from NH2Cl. Dibrominated species of DBPs (i.e., DBAcAm, DBAA and DBAN) were the dominant species formed by both chlorination and chloramination of algal bloom samples. Chloramination of the amino acid asparagine produced an important amount of DCAcAm as compared to chlorination, indicating the existence of a specific reaction pathway.

  16. The removal process of 2,2-dichloroacetamide (DCAcAm), a new disinfection by-product, in drinking water treatment process and its toxicity on zebrafish.

    Science.gov (United States)

    Lin, Tao; Zhou, Dongju; Yu, Shilin; Chen, Wei

    2016-09-01

    The removal process of 2,2-dichloroacetamide (DCAcAm), a new disinfection by-product (DBP) in conventional drinking water treatment plant (C-DWTP) and advanced DWTP (ADWTP) was studied with newly maximum formation potential (MFP) process. It was demonstrated that the advanced treatment displayed greater removal efficiency towards DCAcAm formation potential (MFP) than the conventional treatment. The hydrophilic natural organic matter and natural organic matter with molecular weight 10 kDa leaded to more DCAcAm formation, and the aromatic protein was inferred as one part of DCAcAm precursor. DCAcAm was found to cause delayed development and malformation to zebrafish embryos at embryonic growth stage. Compared with heart toxicity, it caused a significant neuron toxicity. It also could cause the acute DNA damage to adult zebrafish, which should be extremely cautioned. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Do Iodine Contrast Media Compounds Used for Medical Imaging Contribute to the Formation of Iodinated Disinfection By-Products in Drinking Water?

    Science.gov (United States)

    Iodinated disinfection byproducts (DBPs) have recently gained attention due to their cyto- and genotoxicity and increased formation in drinking water treated with chloramine, which has become an increasingly popular disinfectant in the United States. One of these—iodoacetic acid...

  18. Algal toxicity of the alternative disinfectants performic acid (PFA), peracetic acid (PAA), chlorine dioxide (ClO2) and their by-products hydrogen peroxide (H2O2) and chlorite (ClO2-).

    Science.gov (United States)

    Chhetri, Ravi Kumar; Baun, Anders; Andersen, Henrik Rasmus

    2017-05-01

    Environmental effect evaluation of disinfection of combined sewer overflow events with alternative chemical disinfectants requires that the environmental toxicity of the disinfectants and the main by-products of their use are known. Many disinfectants degrade quickly in water which should be included in the evaluation of both their toxicity as determined in standardized tests and their possible negative effect in the water environment. Here we evaluated according to the standardized ISO 8692 test the toxicity towards the green microalgae, Pseudokirchneriella subcapitata, of three disinfectants: performic acid (PFA), peracetic acid (PAA) and chlorine dioxide (ClO 2 ) as well as two by-products of their use: hydrogen peroxide (H 2 O 2 ) and chlorite. All of the five chemicals investigated showed clear toxicity to the algae with well-defined dose response curves. The EC 50 values ranged from 0.16 to 2.9mg/L based on nominal concentrations leading to the labeling of the chemicals as either toxic or very toxic. The five investigated chemicals decreased in toxicity in the order chlorine dioxide, performic acid, peracetic acid, chlorite and hydrogen peroxide. The stability of the chemicals increased in the same order as the toxicity decrease. This indicates that even though ClO 2 has the highest environmental hazard potential, it may still be suitable as an alternative disinfectant due to its rapid degradation in water. Copyright © 2016 Elsevier GmbH. All rights reserved.

  19. The shadow of dichloroacetonitrile (DCAN), a typical nitrogenous disinfection by-product (N-DBP), in the waterworks and its backwash water reuse.

    Science.gov (United States)

    Tan, Yiwen; Lin, Tao; Jiang, Fuchun; Dong, Jian; Chen, Wei; Zhou, Dongju

    2017-08-01

    Dichloroacetonitrile (DCAN) is one of nitrogenous disinfection by-products (N-DBPs) with strong cytotoxicity and genotoxicity. In this study, the formation potential (FP) of DCAN was investigated in the samples of six important water sources located in the Yangtze River Delta. The highest formation concentration of DCAN was 9.05 μg/L in the water sample taken from Taihu Lake with the lowest SUVA value. After the NOM fractionation, the conversion rate of hydrophilic fraction to DCAN was found the highest. Subsequently, a waterworks using Taihu Lake as water source was chosen to research the FP variations of DCAN in the treatment process and backwash water. The results showed that, compared to the conventional treatment process, O/biological activated carbon (BAC) process increased the removal efficiency of DCAN from 21.89% to 50.58% by removing aromatic protein and soluble biological by-products as main precursors of DCAN. The DCAN FP in the effluent of BAC filters using old granular activated carbon was higher than that in the influent and the DCAN FP of its backwash water was lower than that in raw water. In the backwash water of sand filters, the DCAN FP higher than raw water required the recycle ratio less than 5% to avoid the accumulation of DCAN. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Discharges of produced waters from oil and gas extraction via wastewater treatment plants are sources of disinfection by-products to receiving streams

    Science.gov (United States)

    Hladik, Michelle; Focazio, Michael J.; Engle, Mark

    2014-01-01

    Fluids co-produced with oil and gas production (produced waters) are often brines that contain elevated concentrations of bromide. Bromide is an important precursor of several toxic disinfection by-products (DBPs) and the treatment of produced water may lead to more brominated DBPs. To determine if wastewater treatment plants that accept produced waters discharge greater amounts of brominated DBPs, water samples were collected in Pennsylvania from four sites along a large river including an upstream site, a site below a publicly owned wastewater treatment plant (POTW) outfall (does not accept produced water), a site below an oil and gas commercial wastewater treatment plant (CWT) outfall, and downstream of the POTW and CWT. Of 29 DBPs analyzed, the site at the POTW outfall had the highest number detected (six) ranging in concentration from 0.01 to 0.09 μg L− 1 with a similar mixture of DBPs that have been detected at POTW outfalls elsewhere in the United States. The DBP profile at the CWT outfall was much different, although only two DBPs, dibromochloronitromethane (DBCNM) and chloroform, were detected, DBCNM was found at relatively high concentrations (up to 8.5 μg L− 1). The water at the CWT outfall also had a mixture of inorganic and organic precursors including elevated concentrations of bromide (75 mg L− 1) and other organic DBP precursors (phenol at 15 μg L− 1). To corroborate these DBP results, samples were collected in Pennsylvania from additional POTW and CWT outfalls that accept produced waters. The additional CWT also had high concentrations of DBCNM (3.1 μg L− 1) while the POTWs that accept produced waters had elevated numbers (up to 15) and concentrations of DBPs, especially brominated and iodinated THMs (up to 12 μg L− 1 total THM concentration). Therefore, produced water brines that have been disinfected are potential sources of DBPs along with DBP precursors to streams wherever these wastewaters are discharged.

  1. Optical monitoring of Disinfection By-product Precursors with Fluorescence Excitation-Emission Mapping (F-EEM): Practical Application Issues for Drinking, Waste and Reuse Water Industry

    Science.gov (United States)

    Gilmore, A. M.

    2012-12-01

    Drinking water, wastewater and reuse plants must deal with regulations associated with bacterial contamination and halogen disinfection procedures that can generate harmful disinfection by-products (DBPs) including trihalomethanes (THMs), haloacetic acids (HOAAs) and other compounds. The natural fluorescent chromophoric dissolved organic matter (CDOM) is regulated as the major DBP precursor. This study outlines the advantages and current limitations associated with optical monitoring of water treatment processes using tcontemporary Fluorescence Excitation-Emission Mapping (F-EEM). The F-EEM method coupled with practical peak indexing and multi-variate analyses is potentially superior in terms of cost, speed and sensitivity over conventional total organic carbon (TOC) meters and specific UV-absorbance (SUVA) measurements. Hence there is strong interest in developing revised environmental regulations around the F-EEM technique instruments which can incidentally simultaneously measure the SUVA and DOC parameters. Importantly, the F-EEM technique, compared to the single-point TOC and SUVA signals can resolve CDOM classes distinguishing those that strongly cause DBPs. The F-EEM DBP prediction method can be applied to surface water sources to evaluate DBP potential as a function of the point sources and reservoir depth profiles. It can also be applied in-line to rapidly adjust DOC removal processes including sedimentation-flocculation, microfiltration, reverse-osmosis, and ozonation. Limitations and interferences for F-EEMs are discussed including those common to SUVA and TOC in contrast to the advantages including that F-EEMs are less prone to interferences from inorganic carbon and metal contaminations and require little if any chemical preparation. In conclusion, the F-EEM method is discussed in terms of not only the DBP problem but also as a means of predicting (concurrent to DBP monitoring) organic membrane fouling in water-reuse and desalination plants.

  2. Comparative Phytonutrient Analysis of Broccoli By-Products: The Potentials for Broccoli By-Product Utilization.

    Science.gov (United States)

    Liu, Mengpei; Zhang, Lihua; Ser, Suk Lan; Cumming, Jonathan R; Ku, Kang-Mo

    2018-04-13

    The phytonutrient concentrations of broccoli ( Brassica oleracea var. italica) florets, stems, and leaves were compared to evaluate the value of stem and leaf by-products as a source of valuable nutrients. Primary metabolites, including amino acids, organic acids, and sugars, as well as glucosinolates, carotenoids, chlorophylls, vitamins E and K, essential mineral elements, total phenolic content, antioxidant activity, and expression of glucosinolate biosynthesis and hydrolysis genes were quantified from the different broccoli tissues. Broccoli florets had higher concentrations of amino acids, glucoraphanin, and neoglucobrassicin compared to other tissues, whereas leaves were higher in carotenoids, chlorophylls, vitamins E and K, total phenolic content, and antioxidant activity. Leaves were also good sources of calcium and manganese compared to other tissues. Stems had the lowest nitrile formation from glucosinolate. Each tissue exhibited specific core gene expression profiles supporting glucosinolate metabolism, with different gene homologs expressed in florets, stems, and leaves, which suggests that tissue-specific pathways function to support primary and secondary metabolic pathways in broccoli. This comprehensive nutrient and bioactive compound profile represents a useful resource for the evaluation of broccoli by-product utilization in the human diet, and as feedstocks for bioactive compounds for industry.

  3. Comparative Phytonutrient Analysis of Broccoli By-Products: The Potentials for Broccoli By-Product Utilization

    Directory of Open Access Journals (Sweden)

    Mengpei Liu

    2018-04-01

    Full Text Available The phytonutrient concentrations of broccoli (Brassica oleracea var. italica florets, stems, and leaves were compared to evaluate the value of stem and leaf by-products as a source of valuable nutrients. Primary metabolites, including amino acids, organic acids, and sugars, as well as glucosinolates, carotenoids, chlorophylls, vitamins E and K, essential mineral elements, total phenolic content, antioxidant activity, and expression of glucosinolate biosynthesis and hydrolysis genes were quantified from the different broccoli tissues. Broccoli florets had higher concentrations of amino acids, glucoraphanin, and neoglucobrassicin compared to other tissues, whereas leaves were higher in carotenoids, chlorophylls, vitamins E and K, total phenolic content, and antioxidant activity. Leaves were also good sources of calcium and manganese compared to other tissues. Stems had the lowest nitrile formation from glucosinolate. Each tissue exhibited specific core gene expression profiles supporting glucosinolate metabolism, with different gene homologs expressed in florets, stems, and leaves, which suggests that tissue-specific pathways function to support primary and secondary metabolic pathways in broccoli. This comprehensive nutrient and bioactive compound profile represents a useful resource for the evaluation of broccoli by-product utilization in the human diet, and as feedstocks for bioactive compounds for industry.

  4. A pilot solar water disinfecting system: performance analysis and testing

    Energy Technology Data Exchange (ETDEWEB)

    Saitoh, T.S.; El-Ghetany, H.H. [Tohoku University, Sendai (Japan). Dept. of Aeronautics and Space Engineering

    2002-07-01

    In most countries, contaminated water is the major cause of most water-borne diseases. Disinfection of water may be accomplished by a number of different physical-chemical treatments including direct application of thermal energy, chemical and filtration techniques. Solar energy also can be used effectively in this field because inactivation of microorganisms is done either by heating water to a disinfecting temperature or by exposing it to ultraviolet solar radiation. A pilot solar system for disinfecting contaminated water is designed, constructed and tested. Investigations are carried out to evaluate the performance of a wooden hot box solar facility as a solar disinfectant. Experimental data show that solar energy is viable for the disinfection process. A solar radiation model is presented and compared with the experimental data. A mathematical model of the solar disinfectant is also presented. The governing equations are solved numerically via the fourth-order Runge-Kutta method. The effects of environmental conditions (ambient temperature, wind speed, solar radiation, etc.) on the performance of the solar disinfectant are examined. Results showed that the system is affected by ambient temperature, wind speed, ultraviolet solar radiation intensity, the turbidity of the water, the quantity of water exposed, the contact area between the transparent water container in the solar disinfectant and the absorber plate as well as the geometrical parameters of the system. It is pointed out that for partially cloudy conditions with a low ambient temperature and high wind speeds, the thermal efficiency of the solar disinfectant is at a minimum. The use of solar energy for the disinfection process will increase the productivity of the system while completely eliminating the coliform group bacteria at the same time. (author)

  5. Effects of conventional ozonation and electro-peroxone pretreatment of surface water on disinfection by-product formation during subsequent chlorination.

    Science.gov (United States)

    Mao, Yuqin; Guo, Di; Yao, Weikun; Wang, Xiaomao; Yang, Hongwei; Xie, Yuefeng F; Komarneni, Sridhar; Yu, Gang; Wang, Yujue

    2018-03-01

    The electro-peroxone (E-peroxone) process is an emerging ozone-based electrochemical advanced oxidation process that combines conventional ozonation with in-situ cathodic hydrogen peroxide (H 2 O 2 ) production for oxidative water treatment. In this study, the effects of the E-peroxone pretreatment on disinfection by-product (DBP) formation from chlorination of a synthetic surface water were investigated and compared to conventional ozonation. Results show that due to the enhanced transformation of ozone (O 3 ) to hydroxyl radicals (OH) by electro-generated H 2 O 2 , the E-peroxone process considerably enhanced dissolved organic carbon (DOC) abatement and significantly reduced bromate (BrO 3 - ) formation compared to conventional ozonation. However, natural organic matter (NOM) with high UV 254 absorbance, which is the major precursors of chlorination DBPs, was less efficiently abated during the E-peroxone process than conventional ozonation. Consequently, while both conventional ozonation and the E-peroxone process substantially reduced the formation of DBPs (trihalomethanes and haloacetic acids) during post-chlorination, higher DBP concentrations were generally observed during chlorination of the E-peroxone pretreated waters than conventional ozonation treated. In addition, because of conventional ozonation or the E-peroxone treatment, DBPs formed during post-chlorination shifted to more brominated species. The overall yields of brominated DBPs exhibited strong correlations with the bromide concentrations in water. Therefore, while the E-peroxone process can effectively suppress bromide transformation to bromate, it may lead to higher formation of brominated DBPs during post-chlorination compared to conventional ozonation. These results suggest that the E-peroxone process can lead to different DBP formation and speciation during water treatment trains compared to conventional ozonation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Comparative cytotoxic and genotoxic potential of 13 drinking water disinfection by-products using a microplate-based cytotoxicity assay and a developed SOS/umu assay.

    Science.gov (United States)

    Zhang, Shao-Hui; Miao, Dong-Yue; Tan, Li; Liu, Ai-Lin; Lu, Wen-Qing

    2016-01-01

    The implications of disinfection by-products (DBPs) present in drinking water are of public health concern because of their potential mutagenic, carcinogenic and other toxic effects on humans. In this study, we selected 13 main DBPs found in drinking water to quantitatively analyse their cytotoxicity and genotoxicity using a microplate-based cytotoxicity assay and a developed SOS/umu assay in Salmonella typhimurium TA1535/pSK1002. With the developed SOS/umu test, eight DBPs: 3-chloro-4-(dichloromethyl)-5-hydroxy-2[5H]-fura3-chloro-4-(dichloromethyl)-5-hydroxy-2-[5H]-furanone (MX), dibromoacetonitrile (DBN), iodoacetic acid (IA), bromochloroacetonitrile (BCN), bromoacetic acid (BA), trichloroacetonitrile (TCN), dibromoacetic acid (DBA) and dichloroacetic acid (DCA) were significantly genotoxic to S. typhimurium. Three DBPs: chloroacetic acid (CA), trichloroacetic acid (TCA) and dichloroacetonitrile (DCN) were weakly genotoxic, whereas the remaining DBPs: chloroacetonitrile (CN) and chloral hydrate (CH) were negative. The rank order in decreasing genotoxicity was as follows: MX > DBN > IA > BCN > BA > TCN > DBA > DCA > CA, TCA, DCN > CN, CH. MX was approximately 370 000 times more genotoxic than DCA. In the microplate-based cytotoxicity assay, cytotoxic potencies of the 13 DBPs were compared and ranked in decreasing order as follows: MX > IA > DBN > BCN > BA > TCN > DCN > CA > DCA > DBA > CN > TCA > CH. MX was approximately 19 200 times more cytotoxic than CH. A statistically significant correlation was found between cytotoxicity and genotoxicity of the 13 DBPs in S. typhimurium. Results suggest that microplate-based cytotoxicity assay and the developed SOS/umu assay are feasible tools for analysing the cytotoxicity and genotoxicity of DBPs, particularly for comparing their toxic intensities quantitatively. © The Author 2015. Published by Oxford University Press on behalf of the UK Environmental Mutagen Society. All rights reserved. For permissions, please e

  7. Antibacterial Efficiency of Benzalkonium Chloride Base Disinfectant According To European Standard 13727, Chemical Analysis and Validation Studies

    OpenAIRE

    Yıldırım, Çinel; Çelenk, Veysel

    2018-01-01

    Antibacterial Efficiency of Benzalkonium Chloride Base Disinfectant According To European Standard 13727, Chemical Analysis and Validation Studies This study was aimed to provide principle of the chemical analyses, antibacterial efficiency test and validation procedures of the most commonly used benzalkonium chloride (BAC) base disinfectant as a biocide. Disinfectant which comprised 20 % BAC concentration was used as a prototype product and active substance was verified with chemical analysis...

  8. Potential for formation of disinfection by-products from storage of chlorinated surface water in the Basalt aquifer near Fallon, Nevada

    Science.gov (United States)

    Fram, Miranda S.; Maurer, Douglas K.; Lico, Michael S.

    2005-01-01

    Increased pumpage from a basalt aquifer near Fallon, Nevada, has caused its water levels to decline and has induced changes in the quality of water pumped from the basalt. The aquifer is the sole source of water for municipal supply to the city of Fallon, the Naval Air Station Fallon, and the Fallon Paiute-Shoshone Tribe. These changes may be mitigated by storage of surface water in the basalt for subsequent use. Because chlorination of the surface water may be required for storage, the U.S. Geological Survey, in cooperation with the Fallon Paiute-Shoshone Tribe, made laboratory tests using laboratory carbon-organic-free water, surface-water, ground-water, and basaltic-rock samples to determine the potential for formation of disinfection by-products. Experiments with water samples only (no rock and no chlorine) indicated no change in dissolved-organic-carbon (DOC) concentrations over a 20-day reaction period; whereas, all experiments using rock, water, and no chlorine indicated an increase in DOC concentrations. The greatest increase in DOC concentrations for all three water samples occurred in experiments with the rock samples from outcrops on Rattlesnake Hill. Experiments with water only and chlorine yielded a total trihalomethane (THM) concentration of 97.4 ?g/L for the ground-water sample and 347 ?g/L for the surface-water sample. Experiments with mixtures of water, rocks, and chlorine indicated that reactions with the rock consumed chlorine and released significant amounts of organic carbon from the rock, increasing the DOC concentration in the water. The organic carbon in the rocks likely is associated with the secondary clay minerals that line vesicles and fractures in the rocks. THM concentrations were greatest, from 335 to 909 ?g/L, for surface water equilibrated with rock samples from Rattlesnake Hill. However, the concentration of chlorine required to produce these high THM concentrations ranged from 18 to 84 mg/L. The results of the experiments suggest

  9. Sources and characteristics of organic matter in the Clackamas River, Oregon, related to the formation of disinfection by-products in treated drinking water

    Science.gov (United States)

    Carpenter, Kurt D.; Kraus, Tamara E.C.; Goldman, Jami H.; Saraceno, John Franco; Downing, Bryan D.; Bergamaschi, Brian A.; McGhee, Gordon; Triplett, Tracy

    2013-01-01

    This study characterized the amount and quality of organic matter in the Clackamas River, Oregon, to gain an understanding of sources that contribute to the formation of chlorinated and brominated disinfection by-products (DBPs), focusing on regulated DBPs in treated drinking water from two direct-filtration treatment plants that together serve approximately 100,000 customers. The central hypothesis guiding this study was that natural organic matter leaching out of the forested watershed, in-stream growth of benthic algae, and phytoplankton blooms in the reservoirs contribute different and varying proportions of organic carbon to the river. Differences in the amount and composition of carbon derived from each source affects the types and concentrations of DBP precursors entering the treatment plants and, as a result, yield varying DBP concentrations and species in finished water. The two classes of DBPs analyzed in this study-trihalomethanes (THMs) and haloacetic acids (HAAs)-form from precursors within the dissolved and particulate pools of organic matter present in source water. The five principal objectives of the study were to (1) describe the seasonal quantity and character of organic matter in the Clackamas River; (2) relate the amount and composition of organic matter to the formation of DBPs; (3) evaluate sources of DBP precursors in the watershed; (4) assess the use of optical measurements, including in-situ fluorescence, for estimating dissolved organic carbon (DOC) concentrations and DBP formation; and (5) assess the removal of DBP precursors during treatment by conducting treatability "jar-test" experiments at one of the treatment plants. Data collection consisted of (1) monthly sampling of source and finished water at two drinking-water treatment plants; (2) event-based sampling in the mainstem, tributaries, and North Fork Reservoir; and (3) in-situ continuous monitoring of fluorescent dissolved organic matter (FDOM), turbidity, chlorophyll-a, and

  10. Source Water Management for Disinfection By-Product Control using New York City's Operations Support Tool and On-Line Monitoring

    Science.gov (United States)

    Weiss, W. J.; Becker, W.; Schindler, S.

    2012-12-01

    The United States Environmental Protection Agency's 2006 Stage 2 Disinfectant / Disinfection Byproduct Rule (DBPR) for finished drinking waters is intended to reduce overall DBP levels by limiting the levels of total trihalomethanes (TTHM) and five of the haloacetic acids (HAA5). Under Stage 2, maximum contaminant levels (MCLs), 80 μg/L for TTHM and 60 μg/L for HAA5, are based on a locational running annual average for individual sites instead of as the system-wide quarterly running annual average of the Stage 1 DBPR. This means compliance will have to be met at sampling locations of peak TTHM and HAA5 concentrations rather than an average across the entire system. Compliance monitoring under the Stage 2 DBPR began on April 1, 2012. The New York City (NYC) Department of Environmental Protection (DEP) began evaluating potential impacts of the Stage 2 DBPR on NYC's unfiltered water supply in 2002 by monitoring TTHM and HAA5 levels at various locations throughout the distribution system. Initial monitoring indicated that HAA5 levels could be of concern in the future, with the potential to intermittently violate the Stage 2 DBPR at specific locations, particularly those with high water age. Because of the uncertainty regarding the long-term prospect for compliance, DEP evaluated alternatives to ensure compliance, including operational changes (reducing chlorine dose, changing flow configurations to minimize water age, altering pH, altering source water withdrawals); changing the residual disinfectant from free chlorine to chloramines; and engineered treatment alternatives. This paper will discuss the potential for using DEP's Operations Support Tool (OST) and enhanced reservoir monitoring to support optimization of source water withdrawals to minimize finished water DBP levels. The OST is a state-of-the-art decision support system (DSS) to provide computational and predictive support for water supply operations and planning. It incorporates a water supply system

  11. Disinfection of tertiary wastewater effluent prior to river discharge using peracetic acid; treatment efficiency and results on by-products formed in full scale tests.

    Science.gov (United States)

    Pedersen, Per Overgaard; Brodersen, Erling; Cecil, David

    2013-01-01

    This is an investigation of chemical disinfection, with peracetic acid (PAA), in a tertiary sand filter at a full scale activated sludge plant with nitrification/denitrification and P-removal. The reduction efficiency of Escherichia coli and intestinal enterococci in the sand filter is reported. E. coli log reductions of between 0.4 and 2.2 were found with contact times from 6 to 37 min and with dosing from 0 to 4.8 mg L(-1). The average log reduction was 1.3. The decomposition products, bromophenols, chlorophenols and formaldehyde and residual H2O2 were measured before and after the sand filter. The residual H2O2 concentration in the effluent was critical at short contact times and high dosages of PAA due to the discharge limit of 25 μg L(-1). The other three products could not be detected at 0.1 μg L(-1) levels. The chemical cost of PAA dosing is estimated to be 0.039 US$ m(-3) treated wastewater.

  12. The toxicity of a new disinfection by-product, 2,2-dichloroacetamide (DCAcAm), on adult zebrafish (Danio rerio) and its occurrence in the chlorinated drinking water.

    Science.gov (United States)

    Yu, Shilin; Lin, Tao; Chen, Wei; Tao, Hui

    2015-11-01

    The detection method of 2,2-dichloroacetamide (DCAcAm), a new disinfection by-product (DBP) in chlorinated drinking water, was established using a gas chromatograph coupled with a micro-electron capture detector. The chlorinated water samples were taken from ten drinking water treatment plants around Yangtze River or Taihu Lake in China. The concentration of DCAcAm was detected ranging from 0.5 to 1.8μg/L in the waterworks around Yangtze River, and 1.5-2.6μg/L around Taihu Lake. The toxicity of DCAcAm on adult zebrafish was assessed by investigating the metabolism damage with multiple metabolic biomarkers and the accumulation capability with bio-concentration factor. The results showed that DCAcAm could cause the acute metabolism damage and was easily accumulated in zebrafish, and should be extremely cautioned. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. A Summary of Publications on the Development of Mode-of-Action Information and Statistical Tools for Evaluating Health Outcomes from Drinking Water Disinfection By-Product (DBP) Exposures

    Science.gov (United States)

    Chemical contaminants are formed as a consequence of chemical disinfection of public drinking waters. Chemical disinfectants, which are used to kill harmful microorganisms, react with natural organic matter (NOM), bromide, iodide, and other compounds, forming complex mixtures...

  14. APPLICATION OF DNPH DERIVATIZATION WITH LC/MS TO THE IDENTIFICATION OF POLAR CARBONYL DRINKING WATER DISINFECTION BY-PRODUCTS IN DRINKING WATER

    Science.gov (United States)

    A qualitative method using 2,4-dinitrophenylhydrazine (DNPH) derivatization followed by analysis with liquid chromatography (LC)/negative ion-electrospray mass spectrometry (MS) was developed for analyzing and identifying highly polar aldehydes and ketones in ozonated drinking wa...

  15. Ames and random amplified polymorphic DNA tests for the validation of the mutagenic and/or genotoxic potential of the drinking water disinfection by-products chloroform and bromoform.

    Science.gov (United States)

    Khallef, Messaouda; Cenkci, Süleyman; Akyil, Dilek; Özkara, Arzu; Konuk, Muhsin; Benouareth, Djamel Eddine

    2018-01-28

    Chloroform and Bromoform are two abundant trihalomethanes found in Algerian drinking water. The investigation of the mutagenic hazard of these disinfection by-products was studied by Ames test as prokaryotic bioassay to show their mutagenic effects. For this, Salmonella typhimurium TA98 and TA100 strains were employed. Both chloroform and bromoform showed a direct mutagenic effect since the number of revertant colonies gradually increase in dose-dependent manner with all concentrations tested with the two bacterial strains and these were both in the absence and presence of S9 metabolic activation. The genotoxic hazard was also studied by random amplified polymorphic DNA test on the root cells of Allium cepa as eukaryotic bioassay. DNA extracted from the roots of the onion were incubated at different concentrations of chloroform and bromoform and then amplified by polymerase chain reaction. This was based on demonstrating a major effect of disappearance of bands compared to roots incubated in the negative control (distilled water). The results showed that these two compounds affected genomic DNA by breaks although by mutations.

  16. Prospective Power Calculations for the Four Lab Study of A Multigenerational Reproductive/Developmental Toxicity Rodent Bioassay Using A Complex Mixture of Disinfection By-Products in the Low-Response Region

    Directory of Open Access Journals (Sweden)

    Jane Ellen Simmons

    2011-10-01

    Full Text Available In complex mixture toxicology, there is growing emphasis on testing environmentally representative doses that improve the relevance of results for health risk assessment, but are typically much lower than those used in traditional toxicology studies. Traditional experimental designs with typical sample sizes may have insufficient statistical power to detect effects caused by environmentally relevant doses. Proper study design, with adequate statistical power, is critical to ensuring that experimental results are useful for environmental health risk assessment. Studies with environmentally realistic complex mixtures have practical constraints on sample concentration factor and sample volume as well as the number of animals that can be accommodated. This article describes methodology for calculation of statistical power for non-independent observations for a multigenerational rodent reproductive/developmental bioassay. The use of the methodology is illustrated using the U.S. EPA’s Four Lab study in which rodents were exposed to chlorinated water concentrates containing complex mixtures of drinking water disinfection by-products. Possible experimental designs included two single-block designs and a two-block design. Considering the possible study designs and constraints, a design of two blocks of 100 females with a 40:60 ratio of control:treated animals and a significance level of 0.05 yielded maximum prospective power (~90% to detect pup weight decreases, while providing the most power to detect increased prenatal loss.

  17. Prospective Power Calculations for the Four Lab Study of A Multigenerational Reproductive/Developmental Toxicity Rodent Bioassay Using A Complex Mixture of Disinfection By-Products in the Low-Response Region

    Science.gov (United States)

    Dingus, Cheryl A.; Teuschler, Linda K.; Rice, Glenn E.; Simmons, Jane Ellen; Narotsky, Michael G.

    2011-01-01

    In complex mixture toxicology, there is growing emphasis on testing environmentally representative doses that improve the relevance of results for health risk assessment, but are typically much lower than those used in traditional toxicology studies. Traditional experimental designs with typical sample sizes may have insufficient statistical power to detect effects caused by environmentally relevant doses. Proper study design, with adequate statistical power, is critical to ensuring that experimental results are useful for environmental health risk assessment. Studies with environmentally realistic complex mixtures have practical constraints on sample concentration factor and sample volume as well as the number of animals that can be accommodated. This article describes methodology for calculation of statistical power for non-independent observations for a multigenerational rodent reproductive/developmental bioassay. The use of the methodology is illustrated using the U.S. EPA’s Four Lab study in which rodents were exposed to chlorinated water concentrates containing complex mixtures of drinking water disinfection by-products. Possible experimental designs included two single-block designs and a two-block design. Considering the possible study designs and constraints, a design of two blocks of 100 females with a 40:60 ratio of control:treated animals and a significance level of 0.05 yielded maximum prospective power (~90%) to detect pup weight decreases, while providing the most power to detect increased prenatal loss. PMID:22073030

  18. Water-Quality Constituents, Dissolved-Organic-Carbon Fractions, and Disinfection By-Product Formation in Water from Community Water-Supply Wells in New Jersey, 1998-99

    Science.gov (United States)

    Hopple, Jessica A.; Barringer, Julia L.; Koleis, Janece

    2007-01-01

    Water samples were collected from 20 community water-supply wells in New Jersey to assess the chemical quality of the water before and after chlorination, to characterize the types of organic carbon present, and to determine the disinfection by-product formation potential. Water from the selected wells previously had been shown to contain concentrations of dissolved organic carbon (DOC) that were greater than 0.2 mg/L. Of the selected wells, five are completed in unconfined (or semi-confined) glacial-sediment aquifers of the Piedmont and Highlands (New England) Physiographic Provinces, five are completed in unconfined bedrock aquifers of the Piedmont Physiographic Province, and ten are completed in unconsolidated sediments of the Coastal Plain Physiographic Province. Four of the ten wells in the Coastal Plain are completed in confined parts of the aquifers; the other six are in unconfined aquifers. One or more volatile organic compounds (VOCs) were detected in untreated water from all of the 16 wells in unconfined aquifers, some at concentrations greater than maximum contaminant levels. Those compounds detected included aliphatic compounds such as trichloroethylene and 1,1,1-trichloroethane, aromatic compounds such as benzene, the trihalomethane compound, chloroform, and the gasoline additive methyl tert-butyl ether (MTBE). Concentrations of sodium and chloride in water from one well in a bedrock aquifer and sulfate in water from another exceeded New Jersey secondary standards for drinking water. The source of the sulfate was geologic materials, but the sodium and chloride probably were derived from human inputs. DOC fractions were separated by passing water samples through XAD resin columns to determine hydrophobic fractions from hydrophilic fractions. Concentrations of hydrophobic acids were slightly lower than those of combined hydrophilic acids, neutral compounds, and low molecular weight compounds in most samples. Water samples from the 20 wells were adjusted

  19. Mineral composition of fruit by-products evaluated by neutron activation analysis

    International Nuclear Information System (INIS)

    Gabriela de Matuoka e Chiocchetti; Nadai Fernandes de, E.A.; Macio Arruda Bacchi; Rogerio Augusto Pazim; Silvana Regina Vicino Sarries; Thais Melega Tome

    2013-01-01

    Brazil is one of the largest producers of fruits cropping 40 million tons per year. In agro-food processing, approximately 50 % of raw material is discarded generating large amounts of by-products. The lack of information on the nutritional quality of agroindustrial by-products precludes their potential use in the manufacture of food products accessible to all. In this context, the objective of this work was to investigate the nutritional quality of by-products of the industrial processing of fruits. Samples of bagasse, peel and seeds of several fruits (banana, camu camu, coconut, cupuacu, guava, jackfruit, mango, orange, papaya, pineapple, and soursop) were analysed by neutron activation analysis for the determination of Br, Ca, Co, Cr, Cs, Fe, K, La, Na, Rb, Sc and Zn. In general, higher levels of minerals were found in the by-products rather than in the pulps of fruits. This indicates that the use of the by-products should be encouraged, thereby reducing the economic and environmental impact of waste generated by agroindustrial processing. (author)

  20. Application of effect-directed analysis to identify mutagenic nitrogenous disinfection by-products of advanced oxidation drinking water treatment

    NARCIS (Netherlands)

    Vughs, D.; Baken, K.A.; Kolkman, A.; Martijn, A.J.; de Voogt, P.

    Advanced oxidation processes are important barriers for organic micropollutants in (drinking) water treatment. It is however known that medium pressure UV/H2O2 treatment may lead to mutagenicity in the Ames test, which is no longer present after granulated activated carbon (GAC) filtration. Many

  1. Comparative transcriptome and phenotype analysis of Bacillus cereus in response to disinfectant treatments

    NARCIS (Netherlands)

    Ceragioli, Mara; Mols, J.M.; Moezelaar, Roy; Ghelardi, Emilia; Senesi, Sonia; Abee, Tjakko

    2010-01-01

    Antimicrobial chemicals are widely applied to clean and disinfect food-contacting surfaces. However, the cellular response of bacteria, such as Bacillus cereus, to various disinfectants is unclear. In this study, the physiological and genome-wide transcriptional responses of B. cereus ATCC 14579

  2. Comparative transcriptomic and phenotypic analysis of the responses of Bacillus cereus to various disinfectant treatments

    NARCIS (Netherlands)

    Ceragioli, M.; Mols, J.M.; Moezelaar, R.; Ghelardi, E.; Senesi, S.; Abee, T.

    2010-01-01

    Antimicrobial chemicals are widely applied to clean and disinfect food-contacting surfaces. However, the cellular response of bacteria to various disinfectants is unclear. In this study, the physiological and genome-wide transcriptional responses of Bacillus cereus ATCC 14579 exposed to four

  3. Multielemental analysis of agroindustrial by-products employed in animal feeding by INAA

    International Nuclear Information System (INIS)

    Teruya, C.M.; Armelin, M.J.A.; Saiki, M.

    2000-01-01

    Instrumental neutron activation analysis (INAA) with gamma-ray spectrometry was applied to determine As, Ca, Cd, Cl, Co, Cu, Cr, Fe, Hg, K, Mg, Mn, Mo, Na, Sb, Se and Zn in the Brazilian agroindustrial by-products. These materials are widely used in ruminant feeding. The results obtained were compared with requirement and maximum tolerable concentrations. The general conclusions from the data obtained were: (1) many by-products presented concentrations of some essential elements lower than the requirement concentrations, while in some samples the concentrations of Cr, Fe, Mg and Se exceeded by a little the maximum tolerable concentrations, (2) the elements As, Cd, Hg and Sb, generally considered toxic, showed concentrations lower than maximum tolerable values. (author)

  4. Factorial analysis of the trihalomethanes formation in water disinfection using chlorine

    International Nuclear Information System (INIS)

    Rodrigues, Pedro M.S.M.; Esteves da Silva, Joaquim C.G.; Antunes, Maria Cristina G.

    2007-01-01

    The factors that affect trihalomethane (THM) (chloroform, bromodichloromethane, chlorodibromomethane and bromoform) formation from the chlorination of aqueous solutions of hydrophobic fulvic acids (FA) were investigated in a prototype laboratorial simulation using factorial analysis. This strategy involved a fractional factorial design (16 plus 5 center experiments) of five factors (fulvic acids concentration, chlorine dose, temperature, pH and bromide concentration) and a Box Behnken design (12 plus 3 center experiments) for the detailed analysis of three factors (FA concentration, chlorine dose and temperature). The concentration of THM was determined by headspace analysis by GC-ECD. The most significant factors that affect the four THM productions were the following: chloroform-FA concentration and temperature; bromodichloromethane-FA concentration and chlorine dose; chlorodibromomethane-chlorine dose; and, bromoform-chlorine dose and bromide concentration. Moreover, linear models were obtained for the four THM concentrations in the disinfection solution as function of the FA concentration, chlorine dose and temperature, and it was observed that the complexity of the models (number of significant factors and interactions) increased with increasing bromine atoms in the THM. Also, this study shows that reducing the FA concentration the relative amount of bromated THM increases

  5. Disinfectant and antibiotic activities: a comparative analysis in Brazilian hospital bacterial isolates

    Directory of Open Access Journals (Sweden)

    Guimarães Márcia Aparecida

    2000-01-01

    Full Text Available Nosocomial infections are an important cause of morbidity and mortality all over the world. It has been shown that appropriate environmental hygienic and disinfection practices can be very helpful to hospital infection control. The purpose of this study was to evaluate the bactericidal activity of some disinfectants against antibiotic-susceptible and antibiotic-resistant hospital bacterial isolates. The susceptibility of 27 clinical isolates to disinfectants and antibiotics was determined by the Association of Official Analytical Chemist?s (AOAC Use-Dilution method and by the Kirby-Bauer method, respectively. All strains tested were susceptible to sodium hypochlorite, glutaraldehyde and to the association quaternary ammonium - formaldehyde - ethyl alcohol disinfectants. However, the susceptibility of strains to phenol and to one quaternary ammonium compound was variable. Among twenty-one antibiotic-multiresistant strains (methicillin-resistant staphylococci, Enterococcus spp, Pseudomonas aeruginosa, Klebsiella pneumoniae, Proteus mirabilis, Enterobacter cloacae, Serratia marcescens and Escherichia coli eleven (52% and eight (38% strains were resistant to the quaternary ammonium and phenol compounds, respectively. Among six isolates that demonstrated susceptibility to antibiotics (staphylococci, Enterococcus spp, P. mirabilis, E. cloacae and E. coli two strains (33% showed resistance to these disinfectants. The results demonstrated the lack of correlation between antibiotic-susceptibility and susceptibility to disinfectants in hospital strains.

  6. An analysis of a humidifier disinfectant case from a toxicological perspective

    Directory of Open Access Journals (Sweden)

    Kwangsik Park

    2016-07-01

    Full Text Available An analysis of patients and fatalities due to exposure to polyhexamethylene guanidine (PHMG shows that PHMG causes mainly lung diseases such as pulmonary fibrosis. However, no research on the other organs has been conducted on this matter yet. So, an in-depth discussion on toxicological techniques is needed to determine whether or not PHMG is toxic to organs other than just the lungs. For the test of target organ toxicity by PHMG exposure, a toxicokinetic study must first be conducted. However, measurement method for PHMG injected into the body has not yet been established because it is not easy to analyze polymer PHMG, so related base studies on analytical technique for PHMG including radio-labeling chemistry must come first. Moreover, research on exposure-biomarker and effect-biomarker must also be conducted, primarily related to clinical application. Several limitations seem to be expected to apply the biomarker study to the patient because much time has passed after exposure to the humidifier disinfectant. It is why a more comprehensive toxicological researches must be introduced to the causality for the victims.

  7. An analysis of a humidifier disinfectant case from a toxicological perspective.

    Science.gov (United States)

    Park, Kawangsik

    2016-01-01

    An analysis of patients and fatalities due to exposure to polyhexamethylene guanidine (PHMG) shows that PHMG causes mainly lung diseases such as pulmonary fibrosis. However, no research on the other organs has been conducted on this matter yet. So, an in-depth discussion on toxicological techniques is needed to determine whether or not PHMG is toxic to organs other than just the lungs. For the test of target organ toxicity by PHMG exposure, a toxicokinetic study must first be conducted. However, measurement method for PHMG injected into the body has not yet been established because it is not easy to analyze polymer PHMG, so related base studies on analytical technique for PHMG including radio-labeling chemistry must come first. Moreover, research on exposure-biomarker and effect-biomarker must also be conducted, primarily related to clinical application. Several limitations seem to be expected to apply the biomarker study to the patient because much time has passed after exposure to the humidifier disinfectant. It is why a more comprehensive toxicological researches must be introduced to the causality for the victims.

  8. Zinc oxide nanoparticles for water disinfection

    Directory of Open Access Journals (Sweden)

    Emelita Asuncion S. Dimapilis

    2018-03-01

    Full Text Available The world faces a growing challenge for adequate clean water due to threats coming from increasing demand and decreasing supply. Although there are existing technologies for water disinfection, their limitations, particularly the formation of disinfection-by-products, have led to researches on alternative methods. Zinc oxide, an essential chemical in the rubber and pharmaceutical industries, has attracted interest as antimicrobial agent. In nanoscale, zinc oxide has shown antimicrobial properties which make its potential great for various applications. This review discusses the synthesis of zinc oxide with focus on precipitation method, its antimicrobial property and the factors affecting it, disinfection mechanisms, and the potential application to water disinfection.

  9. Chlorination disinfection by-products in drinking water and congenital anomalies: review and meta-analyses Subprodutos da desinfecção com cloro em água potável e anomalias congênitas: revisão e meta-análise

    Directory of Open Access Journals (Sweden)

    Mark J. Nieuwenhuijsen

    2010-10-01

    Full Text Available This study aims to review epidemiologic evidence of the association between exposure to chlorination disinfection by-products (DBPs and congenital anomalies. All epidemiologic studies that evaluated a relationship between an index of DBP exposure and risk of congenital anomalies were analyzed. For all congenital anomalies combined, the meta-analysis gave a statistically significant excess risk for high versus low exposure to water chlorination or TTHM (17%; 95% CI, 3-34 based on a small number of studies. The meta-analysis also suggested a statistically significant excess risk for ventricular septal defects (58%; 95% CI, 21-107, but based on only three studies, and there was little evidence of an exposure-response relationship. It was observed no statistically significant relationships in the other meta-analyses and little evidence for publication bias, except for urinary tract defects and cleft lip and palate. Although some individual studies have suggested an association between chlorination disinfection by-products and congenital anomalies, meta-analyses of all currently available studies demonstrate little evidence of such association.O objetivo deste estudo é revisar evidências epidemiológicas da associação entre a exposição a subprodutos da desinfecção com cloro (DBPs e anomalias congênitas. Todos os estudos epidemiológicos que avaliaram a relação entre o índice de exposição a DBPs e o risco de anomalias congênitas foram analisados. Para todas as anomalias congênitas combinadas, a meta-análise resultou em um risco de excesso estatisticamente significante para alta versus baixa exposição à cloração da água ou ao TTHM (17%; 95% CI, 3-34 baseado em um pequeno número de estudos. A meta-análise também sugere um excesso de risco estatisticamente significante para defeitos septais ventriculares (58%; 95% CI, 21-107, porém com base em apenas três estudos, nos quais se encontrou pouca evidência na relação exposi

  10. Hazard Analysis and identification of Critical Control Points of collagen extraction from cod by-products

    NARCIS (Netherlands)

    Aalberts, C.H.J.

    2004-01-01

    The aim of the European research project “UTILISATION AND STABILISATION OF BY-PRODUCTS FROM COD SPECIES” (QLK1-CT-2000-01017 QLRT-2001-02829) is to investigate whether collagen from fish by-products could serve as an important raw material in high quality food. Since Atlantic cod is a major

  11. Hygienic measures during animal transport to abattoirs - a status quo analysis of the current cleaning and disinfection of animal transporters in Germany.

    Science.gov (United States)

    Weber, Luisa; Meemken, Diana

    2018-01-01

    The process of cleaning and disinfection of animal transport vehicles after unloading animals at the abattoir is a critical control point regarding proper hygiene. It is an important step regarding the biosecurity. In the present study, a status quo analysis of the currently performed cleaning and disinfection measures of animal transport vehicles was carried out at the vehicle washing facilities of five different industrial abattoirs in Germany. For this purpose, a checklist was developed and validated to assess the washing procedure of transport vehicles in a standardised way. The evaluated phases of cleaning included the evaluation criteria "length of time per used floor", "visual cleaning success" and the "hygienic awareness of the driver". During disinfection, attention was paid to the internal and external surfaces of the transporter and to the methods used to disinfect them. In addition, the technical and structural equipment of the five different washing facilities were recorded using a questionnaire and compared to the legal regulations, respectively. At each location, approximately 150 vehicles of all delivery types (transport vehicles owned by the abattoir, external delivery companies and vehicles owned by the supplying farmers) were inspected so that in total a number of more than 750 vehicles were included in this study. The aim was to develop abattoir specific, as well as generally applicable intervention measures and to generate "standard-operation procedures" (SOP's) for the cleaning and disinfection of animal transporters. At two out of five locations vehicles have left the abattoir without cleaning and disinfection. In 31-97% of all vehicles, only a cleaning of the vehicle was carried out, a subsequent disinfection did not take place. A cleaning followed by disinfecting took place in only 3-59% of all vehicles. The results indicate a considerable need for improvement and standardisation in this relevant field of disease prevention.

  12. Direct analysis in real time mass spectrometry of potential by-products from homemade nitrate ester explosive synthesis.

    Science.gov (United States)

    Sisco, Edward; Forbes, Thomas P

    2016-04-01

    This work demonstrates the coupling of direct analysis in real time (DART) ionization with time-of-flight mass spectrometry (MS) in an off-axis configuration for the trace detection and analysis of potential partially nitrated and dimerized by-products of homemade nitrate ester explosive synthesis. Five compounds relating to the synthesis of nitroglycerin (NG) and pentaerythritol tetranitrate (PETN) were examined. Deprotonated ions and adducts with molecular oxygen, nitrite, and nitrate were observed in the mass spectral responses of these compounds. A global optimum temperature of 350 °C for the by-products investigated here enabled single nanogram to sub nanogram trace detection. Matrix effects were examined through a series of mixtures containing one or more compounds (sugar alcohol precursors, by-products, and/or explosives) across a range of mass loadings. The explosives MS responses experienced competitive ionization in the presence of all by-products. The magnitude of this influence corresponded to both the degree of by-product nitration and the relative mass loading of the by-product to the explosive. This work provides a characterization of potential by-products from homemade nitrate ester synthesis, including matrix effects and potential challenges that might arise from the trace detection of homemade explosives (HMEs) containing impurities. Detection and understanding of HME impurities and complex mixtures may provide valuable information for the screening and sourcing of homemade nitrate ester explosives. Published by Elsevier B.V.

  13. Ultraviolet disinfection of potable water

    Energy Technology Data Exchange (ETDEWEB)

    Wolfe, R. L. [Metropolitan Water District of Southern California, Los Angeles, CA (United States)

    1990-06-15

    Because of upcoming surface and groundwater regulations regarding the control of microbiological and chemical contaminants, there is a need to evaluate the feasibility and effectiveness of ultraviolet (UV) radiation for primary disinfection of potable water supplies. Data is presented on microbicidal wavelengths of UV and distribution of energy output for low and medium-pressure arc lamps. Both systems were found to perform equally well for inactivating microorganisms, but each had distinct advantages in different applications. Approximate dosages for 90% inactivation of selected microorganisms by UV is presented in a table. Cost analysis for disinfection is presented in two tables as well as the advantages and disadvantages of UV disinfection.

  14. Ultraviolet disinfection of potable water

    International Nuclear Information System (INIS)

    Wolfe, R.L.

    1990-01-01

    Because of upcoming surface and groundwater regulations regarding the control of microbiological and chemical contaminants, there is a need to evaluate the feasibility and effectiveness of ultraviolet (UV) radiation for primary disinfection of potable water supplies. Data is presented on microbicidal wavelengths of UV and distribution of energy output for low and medium-pressure arc lamps. Both systems were found to perform equally well for inactivating microorganisms, but each had distinct advantages in different applications. Approximate dosages for 90% inactivation of selected microorganisms by UV is presented in a table. Cost analysis for disinfection is presented in two tables as well as the advantages and disadvantages of UV disinfection

  15. Ozone reactions with indoor materials during building disinfection

    DEFF Research Database (Denmark)

    Poppendieck, D.; Hubbard, H.; Ward, M.

    2007-01-01

    , and particularly after several hours of disinfection, surface reaction resistance dominated the overall resistance to ozone deposition for nearly all materials. Total building disinfection by-products (all carbonyls) were quantified per unit area of each material for the experimental period. Paper, office...... partition, and medium density fiberboard each released greater than 38 mg m(-2) of by-products....

  16. Comparative analysis of solar pasteurization versus solar disinfection for the treatment of harvested rainwater.

    Science.gov (United States)

    Strauss, André; Dobrowsky, Penelope Heather; Ndlovu, Thando; Reyneke, Brandon; Khan, Wesaal

    2016-12-09

    Numerous pathogens and opportunistic pathogens have been detected in harvested rainwater. Developing countries, in particular, require time- and cost-effective treatment strategies to improve the quality of this water source. The primary aim of the current study was thus to compare solar pasteurization (SOPAS; 70 to 79 °C; 80 to 89 °C; and ≥90 °C) to solar disinfection (SODIS; 6 and 8 hrs) for their efficiency in reducing the level of microbial contamination in harvested rainwater. The chemical quality (anions and cations) of the SOPAS and SODIS treated and untreated rainwater samples were also monitored. While the anion concentrations in all the samples were within drinking water guidelines, the concentrations of lead (Pb) and nickel (Ni) exceeded the guidelines in all the SOPAS samples. Additionally, the iron (Fe) concentrations in both the SODIS 6 and 8 hr samples were above the drinking water guidelines. A >99% reduction in Escherichia coli and heterotrophic bacteria counts was then obtained in the SOPAS and SODIS samples. Ethidium monoazide bromide quantitative polymerase chain reaction (EMA-qPCR) analysis revealed a 94.70% reduction in viable Legionella copy numbers in the SOPAS samples, while SODIS after 6 and 8 hrs yielded a 50.60% and 75.22% decrease, respectively. Similarly, a 99.61% reduction in viable Pseudomonas copy numbers was observed after SOPAS treatment, while SODIS after 6 and 8 hrs yielded a 47.27% and 58.31% decrease, respectively. While both the SOPAS and SODIS systems reduced the indicator counts to below the detection limit, EMA-qPCR analysis indicated that SOPAS treatment yielded a 2- and 3-log reduction in viable Legionella and Pseudomonas copy numbers, respectively. Additionally, SODIS after 8 hrs yielded a 2-log and 1-log reduction in Legionella and Pseudomonas copy numbers, respectively and could be considered as an alternative, cost-effective treatment method for harvested rainwater.

  17. Breakthrough analysis for water disinfection using silver nanoparticles coated resin beads in fixed-bed column

    International Nuclear Information System (INIS)

    Mthombeni, Nomcebo H.; Mpenyana-Monyatsi, Lizzy; Onyango, Maurice S.; Momba, Maggie N.B.

    2012-01-01

    Highlights: ► Performance of silver nanoparticles coated resin in water disinfection is presented. ► Sigmoidal models are used to describe breakthrough curves. ► The performance of the media in water disinfection is affected by process variables. ► Test with environmental water shows the media is effective in water disinfection. - Abstract: This study demonstrates the use of silver nanoparticles coated resin beads in deactivating microbes in drinking water in a column filtration system. The coated resin beads are characterized using X-ray diffraction (XRD), Fourier transform infra-red (FT-IR), scanning electron microscope (SEM), transmission electron microscope (TEM) and energy dispersive spectroscopy (EDS) to confirm the functional groups, morphology and the presence of silver nanoparticles on the surface of the resin. The performance of the coated resin is evaluated as a function of bed mass, initial bacterial concentration and flow rate using Escherichia coli as model microbial contaminant in water. The survival curves of E. coli are expressed as breakthrough curves (BTCs), which are modeled using sigmoidal regression equations to obtain relevant rate parameters. The number of bed volumes processed at breakthrough point and capacity of the bed are used as performance indicators. Results show that performance increases with a decrease in initial bacterial concentration, an increase in flow rate and an increase in bed mass.

  18. Fluorimetric analysis of gallium in bauxite, by-products, products from gallium processing and its control solutions

    International Nuclear Information System (INIS)

    Ferreira, C.A.M.; Medeiros, V.

    1987-01-01

    The gallium processing since raw material analysis until end-products analysis is studied. Gallium presence in by-products and products, as well as the fluorimetric method is analyzed. Equipments and materials used in laboratory, reagents and chemical solutions are described. (M.J.C.) [pt

  19. Statistical Analysis and ETAS Modeling of Seismicity Induced by Production of Geothermal Energy from Hydrothermal Systems

    Science.gov (United States)

    Dinske, C.; Langenbruch, C.; Shapiro, S. A.

    2017-12-01

    We investigate seismicity related to hydrothermal systems in Germany and Italy, focussing on temporal changes of seismicity rates. Our analysis was motivated by numerical simulations The modeling of stress changes caused by the injection and production of fluid revealed that seismicity rates decrease on a long-term perspective which is not observed in the considered case studies. We analyze the waiting time distributions of the seismic events in both time domain (inter event times) and fluid volume domain (inter event volume). We find clear indications that the observed seismicity comprises two components: (1) seismicity that is directly triggered by production and re-injection of fluid, i.e. induced events, and (2) seismicity that is triggered by earthquake interactions, i.e. aftershock triggering. In order to better constrain our numerical simulations using the observed induced seismicity we apply catalog declustering to seperate the two components. We use the magnitude-dependent space-time windowing approach introduced by Gardner and Knopoff (1974) and test several published algorithms to calculate the space-time windows. After declustering, we conclude that the different hydrothermal reservoirs show a comparable seismic response to the circulation of fluid and additional triggering by earthquake interactions. The declustered catalogs contain approximately 50 per cent of the number of events in the original catalogs. We then perform ETAS (Epidemic Type Aftershock; Ogata, 1986, 1988) modeling for two reasons. First, we want to know whether the different reservoirs are also comparable regarding earthquake interaction patterns. Second, if we identify systematic patterns, ETAS modeling can contribute to forecast seismicity during production of geothermal energy. We find that stationary ETAS models cannot accurately capture real seismicity rate changes. One reason for this finding is given by the rate of observed induced events which is not constant over time. Hence

  20. Evaluation of thirteen haloacetic acids and ten trihalomethanes formation by peracetic acid and chlorine drinking water disinfection.

    Science.gov (United States)

    Xue, Runmiao; Shi, Honglan; Ma, Yinfa; Yang, John; Hua, Bin; Inniss, Enos C; Adams, Craig D; Eichholz, Todd

    2017-12-01

    Free chlorine is a commonly used disinfectant in drinking water treatment. However, disinfection by-products (DBPs) are formed during water disinfection. Haloacetic acids (HAAs) and trihalomethanes (THMs) are two major groups of DBPs. Iodo-HAAs and iodo-THMs (I-HAAs and I-THMs) are formed during the disinfection of the water containing high levels of iodide and are much more toxic than their chlorinated and brominated analogs. Peracetic acid (PAA) is a strong antimicrobial disinfectant that is expected to reduce the formation of HAAs and THMs during disinfection. In this study, the formations of thirteen HAAs and ten THMs, including the iodinated forms, have been investigated during PAA disinfection and chlorination as the comparison. The DBP formations under different iodide concentrations, pHs, and contact times were systematically investigated. Two types of commercial PAAs containing different concentrations of PAA and hydrogen peroxide (H 2 O 2 ) were studied. A solid-phase microextraction gas chromatography-mass spectrometry method was upgraded for THM analysis including I-THMs. HAAs were analyzed by following a recently developed high performance ion chromatography-tandem mass spectrometry method. Results show that the ratio of PAA and H 2 O 2 concentration significantly affect the formation of I-THMs and I-HAAs. During PAA disinfection with lower PAA than H 2 O 2 , no detectable levels of THMs and HAAs were observed. During PAA disinfection with higher PAA than H 2 O 2 , low levels of monoiodoacetic acid, diiodoacetic acid, and iodoform were formed, and these levels were enhanced with the increase of iodide concentration. No significant quantities of chloro- or bromo-THMs and HAAs were formed during PAA disinfection treatment. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Global Foot-and-Mouth Disease Research Update and Gap Analysis: 5 - Biotherapeutics and Disinfectants.

    Science.gov (United States)

    Robinson, L; Knight-Jones, T J D; Charleston, B; Rodriguez, L L; Gay, C G; Sumption, K J; Vosloo, W

    2016-06-01

    We assessed knowledge gaps in foot-and-mouth disease (FMD) research. Findings are reported in a series of papers, and in this article, we consider biotherapeutics and disinfectants. The study took the form of a literature review (2011-2015) combined with research updates collected in 2014 from 33 institutes from across the world. Findings were used to identify priority areas for future FMD research. While vaccines will remain the key immunological intervention used against FMD virus (FMDV) for the foreseeable future, it takes a few days for the immune system to respond to vaccination. In an outbreak situation, protection could potentially be provided during this period by the application of rapid, short-acting biotherapeutics, aiming either to stimulate a non-specific antiviral state in the animal or to specifically inhibit a part of the viral life cycle. Certain antiviral cytokines have been shown to promote rapid protection against FMD; however, the effects of different immune-modulators appear to vary across species in ways and for reasons that are not yet understood. Major barriers to the effective incorporation of biotherapeutics into control strategies are cost, limited understanding of their effect on subsequent immune responses to vaccines and uncertainty about their potential impact if used for disease containment. Recent research has highlighted the importance of environmental contamination in FMDV transmission. Effective disinfectants for FMDV have long been available, but research is being conducted to further develop methods for quantitatively evaluating their performance under field, or near-field, conditions. During outbreaks in South Korea in 2010 there was public concern about potential environmental contamination after the mass use of disinfectant and mass burial of culled stock; this should be considered during outbreak contingency planning. © 2016 Blackwell Verlag GmbH.

  2. Nitrogenous disinfection byproducts in English drinking water supply systems: Occurrence, bromine substitution and correlation analysis.

    Science.gov (United States)

    Bond, Tom; Templeton, Michael R; Mokhtar Kamal, Nurul Hana; Graham, Nigel; Kanda, Rakesh

    2015-11-15

    Despite the recent focus on nitrogenous disinfection byproducts in drinking water, there is limited occurrence data available for many species. This paper analyses the occurrence of seven haloacetonitriles, three haloacetamides, eight halonitromethanes and cyanogen chloride in 20 English drinking water supply systems. It is the first survey of its type to compare bromine substitution factors (BSFs) between the haloacetamides and haloacetonitriles. Concentrations of the dihalogenated haloacetonitriles and haloacetamides were well correlated. Although median concentrations of these two groups were lower in chloraminated than chlorinated surface waters, median BSFs for both in chloraminated samples were approximately double those in chlorinated samples, which is significant because of the higher reported toxicity of the brominated species. Furthermore, median BSFs were moderately higher for the dihalogenated haloacetamides than for the haloacetonitriles. This indicates that, while the dihalogenated haloacetamides were primarily generated from hydrolysis of the corresponding haloacetonitriles, secondary formation pathways also contributed. Median halonitromethane concentrations were remarkably unchanging for the different types of disinfectants and source waters: 0.1 μg · mgTOC(-1) in all cases. Cyanogen chloride only occurred in a limited number of samples, yet when present its concentrations were higher than the other N-DBPs. Concentrations of cyanogen chloride and the sum of the halonitromethanes were not correlated with any other DBPs. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Sewage sludges disinfection

    International Nuclear Information System (INIS)

    Alexandre, D.

    1977-01-01

    There is an hygienic risk in using biological sewage sludges for agriculture. Systematic analysis carried out on sludges samples obtained from purification plants in East and South part of France, show the almost uniform presence of pathogenic microorganisms. Some of it survive more than 9 months after soil application. Conventional process for disinfection: liming and heat are not suitable for agricultural use. On the other hand, irradiation involves no modification in structure and composition of sludges. Radiation doses required for disinfection vary according to microorganisms. If some of them are eliminated with rather light doses (200 krad) mycobacteria, viruses and eggs of worms resist to more important doses. Security dose is estimated around 1000 krad

  4. Direct Analysis in Real Time Mass Spectrometry of Potential By-Products from Homemade Nitrate Ester Explosive Synthesis

    OpenAIRE

    Sisco, Edward; Forbes, Thomas P.

    2015-01-01

    This work demonstrates the coupling of direct analysis in real time (DART) ionization with time-of-flight mass spectrometry (MS) in an off-axis configuration for the trace detection and analysis of potential partially nitrated and dimerized by-products of homemade nitrate ester explosive synthesis. Five compounds relating to the synthesis of nitroglycerin (NG) and pentaerythritol tetranitrate (PETN) were examined. Deprotonated ions and adducts with molecular oxygen, nitrite, and nitrate were ...

  5. Formation of Staphylococcus aureus Biofilm in the Presence of Sublethal Concentrations of Disinfectants Studied via a Transcriptomic Analysis Using Transcriptome Sequencing (RNA-seq)

    Science.gov (United States)

    Oppelt, J.; Cincarova, L.

    2017-01-01

    ABSTRACT Staphylococcus aureus is a common biofilm-forming pathogen. Low doses of disinfectants have previously been reported to promote biofilm formation and to increase virulence. The aim of this study was to use transcriptome sequencing (RNA-seq) analysis to investigate global transcriptional changes in S. aureus in response to sublethal concentrations of the commonly used food industry disinfectants ethanol (EtOH) and chloramine T (ChT) and their combination (EtOH_ChT) in order to better understand the effects of these agents on biofilm formation. Treatment with EtOH and EtOH_ChT resulted in more significantly altered expression profiles than treatment with ChT. Our results revealed that EtOH and EtOH_ChT treatments enhanced the expression of genes responsible for regulation of gene expression (sigB), cell surface factors (clfAB), adhesins (sdrDE), and capsular polysaccharides (cap8EFGL), resulting in more intact biofilm. In addition, in this study we were able to identify the pathways involved in the adaptation of S. aureus to the stress of ChT treatment. Further, EtOH suppressed the effect of ChT on gene expression when these agents were used together at sublethal concentrations. These data show that in the presence of sublethal concentrations of tested disinfectants, S. aureus cells trigger protective mechanisms and try to cope with them. IMPORTANCE So far, the effect of disinfectants is not satisfactorily explained. The presented data will allow a better understanding of the mode of disinfectant action with regard to biofilm formation and the ability of bacteria to survive the treatment. Such an understanding could contribute to the effort to eliminate possible sources of bacteria, making disinfectant application as efficient as possible. Biofilm formation plays significant role in the spread and pathogenesis of bacterial species. PMID:29030437

  6. [Experimental evaluation of the spraying disinfection efficiency on dental models].

    Science.gov (United States)

    Zhang, Yi; Fu, Yuan-fei; Xu, Kan

    2013-08-01

    To evaluate the disinfect effect after spraying a new kind of disinfectant on the dental plaster models. The germ-free plaster samples, which were smeared with bacteria compound including Staphylococcus aureus, Escherichia coli, Saccharomyces albicans, Streptococcus mutans and Actinomyces viscosus were sprayed with disinfectants (CaviCide) and glutaraldehyde individually. In one group(5 minutes later) and another group(15 minutes later), the colonies were counted for statistical analysis after sampling, inoculating, and culturing which were used for evaluation of disinfecting efficiency. ANOVA was performed using SPSS12.0 software package. All sample bacteria were eradicated after spraying disinfectants(CaviCide) within 5 minutes and effective bacteria control was retained after 15 minutes. There was significant difference between the disinfecting efficiency of CaviCide and glutaraldehyde. The effect of disinfection with spraying disinfectants (CaviCide) on dental models is quick and effective.

  7. Performance analysis of a solar photovoltaic hybrid system for electricity generation and simultaneous water disinfection of wild bacteria strains

    International Nuclear Information System (INIS)

    Pichel, N.; Vivar, M.; Fuentes, M.

    2016-01-01

    Highlights: • A new hybrid solar water disinfection and energy generation system was designed and tested. • SOLWAT comprises a water disinfection reactor and a PV module fully integrated into a single unit. • Natural water with wild strains of E. coli, Enterococcus spp. and C. perfringens were studied. • The water disinfection reactor located above the PV module did not affect the final energy output. • The SOLWAT disinfection results were always higher than conventional PET bottles. - Abstract: A hybrid solar water disinfection and energy generation system for meeting the needs of safe drinking water and electricity was designed and tested in Alcalá de Henares (Spain) under summer climatic conditions to demonstrate the feasibility of the concept. Natural water sources with wild strains of Escherichia coli, total coliforms, Enterococcus spp. and Clostridium perfringens (including spores) were studied. Results showed that SOLWAT disinfection efficiency was higher than conventional PET bottles and that the water disinfection reactor located above the PV module did not affect the total energy output produced by the hybrid system in comparison to the single PV module, achieving the same power losses over the 6 h of sun exposure in relation to their power at standard test conditions (STC).

  8. Biodosimetric analysis of medium pressure UV disinfection reactor treating unfiltered surface water

    International Nuclear Information System (INIS)

    Leinan, B.E.; Craik, S.A.; Smith, D.W.; Belosevic, M.

    2002-01-01

    Many small and medium-sized communities use chlorination of surface water as their sole treatment of potable water. Ultraviolet (UV) disinfection may offer these communities a cost effective treatment option for protection against pathogens not readily inactivated by chlorine. The effectiveness of UV reactors for microorganism reduction, however, is sensitive to UV dose delivery, which is in turn influenced by water quality characteristics. The effectiveness of a Calgon Carbon Inc. Sentinel medium-pressure UV reactor for microorganism reduction was determined using biodosimetry with two non-pathogenic indicator organisms - MS2 phage and Bacillus subtilis. Testing was conducted using low turbidity (<0.5 NTU) lake water characterized by relatively high absorbance in the UV range (UVT of approx. 87 to 88% at 254 nm). The efficiency of UV dose delivery in the reactor was determined for various operating conditions by calculating the normalized reductive equivalent irradiance (REI). With a single lamp in operation, the normalized REI measured with B. subtilis increased significantly when the flow rate through the reactor was increased from 380 L/min to 1140 L/min. This increase in reactor efficiency was believed to be due to improved reactor hydrodynamics and axial mixing that accompanied the higher flow rates. In contrast, treatment efficiency based on biodosimetry with MS2 phage was found to decrease with increasing flow rate when a single lamp was in operation. In general, treatment efficiency was greater when more than one adjacent lamp was in operation, suggesting that the influence of flow short-circuiting with single lamp operation. Differences between the outcomes observed with the two indicator microorganisms were not resolved, however, it was concluded that reactor efficiency was sensitive to both water flow rate and the number of adjacent lamps that were in operation. (author)

  9. Desalinated and blended water in Saudi Arabia: human exposure and risk analysis from disinfection byproducts

    Directory of Open Access Journals (Sweden)

    Chowdhury Imran Rahman

    2017-01-01

    Full Text Available Saudi Arabia produces the largest amount of desalinated water as a single country. The desalinated water is typically blended with treated groundwater, pH adjusted and chlorinated prior to supply to the communities. The desalinated seawater and/or blended water contains various types of disinfection byproducts (DBPs, some of which may induce cancer risks to human through lifetime exposure. In this study, occurrences of trihalomethanes (THMs in desalinated and blended water in Saudi Arabia were investigated and their exposure and risks were predicted. The chronic daily intakes of CHCl3, BDCM, DBCM and CHBr3 were estimated to be 8.38×10−5, 7.57×10−5, 2.54×10−5 and 4.32×10−4 mg/kg-day respectively. The overall cancer risk was 1.78×10−5 with the range of 7.40×10−7 – 9.26×10−5 and the average hazard index was 3.49×10−2 with the range of 1.20×10−3 – 2.34×10−1. The loss of disability adjusted life years (DALY were estimated to be 25.1 per year and the average cancer risk had 8.48×10−7 DALY per person per year. The financial burden was estimated to be US$2.72 million with the range of US$2.52–2.91 million. The findings may assist in better understanding and reducing cancer risks from DBPs in desalinated and blended water.

  10. Spiral-shaped disinfection reactors

    KAUST Repository

    Ghaffour, Noreddine

    2015-08-20

    This disclosure includes disinfection reactors and processes for the disinfection of water. Some disinfection reactors include a body that defines an inlet, an outlet, and a spiral flow path between the inlet and the outlet, in which the body is configured to receive water and a disinfectant at the inlet such that the water is exposed to the disinfectant as the water flows through the spiral flow path. Also disclosed are processes for disinfecting water in such disinfection reactors.

  11. Assesment of disinfectant by product in chlorinated drinking water

    International Nuclear Information System (INIS)

    Khattak, M.I.

    2010-01-01

    The present study was design to establish the report of spatial pattern and variations of Trihalomethanes (THMs) in drinking water sample collected from the area of Karachi. This is the first attempt of its nature to assess mainly the THMs level in drinking water samples of this region. THMs occurrence in water samples as investigated based on a program for preliminary monitoring of water quality throughout the distribution system. The most important species CHCl/sub 3/ of THMs were measured in the samples and were found at average level. The results of present investigation demonstrated that there are more than 95.06% of total Trihalomethanes spatial variations. Specially the CHCl/sub 3/ is considerable in all the utilities in question. (author)

  12. Monitoring natural organic matter and disinfection by-products at ...

    African Journals Online (AJOL)

    COD) and conductivity. Water samples were collected from two water treatment plants in South Africa, namely Sedibeng (Balkfontein) and Midvaal. The overall TOC reduction after the water treatment processes was 33% and 30% at Midvaal and ...

  13. Spiral-shaped disinfection reactors

    KAUST Repository

    Ghaffour, NorEddine; Ait-Djoudi, Fariza; Naceur, Wahib Mohamed; Soukane, Sofiane

    2015-01-01

    This disclosure includes disinfection reactors and processes for the disinfection of water. Some disinfection reactors include a body that defines an inlet, an outlet, and a spiral flow path between the inlet and the outlet, in which the body

  14. A rapid analysis of {sup 226}Ra in raw materials and by-products using gamma-ray spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Chung Sup; Chung, Kun Ho; Kim, Chang Jong; Ji, Young Yong [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2017-03-15

    A gamma-ray peak of {sup 226}Ra (186.2 keV) overlaps with one of {sup 235}U (185.7 keV) in a gamma-ray spectrometry system. Though reference peaks of {sup 235}U can be used to correct the peak interference of {sup 235}U in the analysis of {sup 226}Ra, this requires a complicated calculation process and a high limit of quantitation. On the other hand, evaluating {sup 226}Ra using the correction constant in the overlapped peak can make a rapid measurement of {sup 226}Ra without the complicated calculation process as well as overcome the disadvantage in the indirect measurement of {sup 214}Bi, which means the confinement of {sup 222}Rn gas in a sample container and a time period to recover the secular equilibrium. About 93 samples with 6 species for raw-materials and by-products were prepared to evaluate the activity of {sup 226}Ra using the correction constant. The results were compared with the activity of {sup 214}Bi, which means the indirect measurement of {sup 226}Ra, to validate the method of the direct measurement of {sup 226}Ra using the correction constant. The difference between the direct and indirect measurement of {sup 226}Ra was generally below about ± 20%. However, in the case of the phospho gypsum, a large error of about 50% was found in the comparison results, which indicates the disequilibrium between {sup 238}U and {sup 226}Ra in the materials. Application results of the contribution ratio of {sup 226}Ra were below about ± 10% . The direct measurement of {sup 226}Ra using the correction constant can be an effective method for its rapid measurement of raw materials and by-products because the activity of {sup 226}Ra can be produced with a simple calculation without the consideration of the integrity of a sample container and the time period to recover the secular equilibrium.

  15. Applications of Photocatalytic Disinfection

    Directory of Open Access Journals (Sweden)

    Joanne Gamage

    2010-01-01

    Full Text Available Due to the superior ability of photocatalysis to inactivate a wide range of harmful microorganisms, it is being examined as a viable alternative to traditional disinfection methods such as chlorination, which can produce harmful byproducts. Photocatalysis is a versatile and effective process that can be adapted for use in many applications for disinfection in both air and water matrices. Additionally, photocatalytic surfaces are being developed and tested for use in the context of “self-disinfecting” materials. Studies on the photocatalytic technique for disinfection demonstrate this process to have potential for widespread applications in indoor air and environmental health, biological, and medical applications, laboratory and hospital applications, pharmaceutical and food industry, plant protection applications, wastewater and effluents treatment, and drinking water disinfection. Studies on photocatalytic disinfection using a variety of techniques and test organisms are reviewed, with an emphasis on the end-use application of developed technologies and methods.

  16. Review and Analysis of Alternatives for the Valorisation of Agro-Industrial Olive Oil By-Products

    Directory of Open Access Journals (Sweden)

    Julio Berbel

    2018-01-01

    Full Text Available By-products and waste from olive production (agriculture and the olive oil industry (mills and refineries are an important environmental issue in Mediterranean areas. Industrial waste and by-products contain highly valuable components that can also be phytotoxic. This article reviews recent research on the valorisation of olive by-products under the bioeconomy strategy. The alternatives are classified according to the ‘bioeconomy value pyramid’, which prioritises higher value uses over the current energy and compost valorisation. Special attention is paid to the use of these by-products for animal feed that can be improved by reducing the content of saturated fatty acids (SFAs and increase the polyunsaturated fatty acids amount considered beneficial in response to their use; this makes the food healthier for humans while simultaneously reducing feeding costs and the environmental impact of livestock.

  17. An analysis of a humidifier disinfectant case from a toxicological perspective

    OpenAIRE

    Kwangsik Park

    2016-01-01

    An analysis of patients and fatalities due to exposure to polyhexamethylene guanidine (PHMG) shows that PHMG causes mainly lung diseases such as pulmonary fibrosis. However, no research on the other organs has been conducted on this matter yet. So, an in-depth discussion on toxicological techniques is needed to determine whether or not PHMG is toxic to organs other than just the lungs. For the test of target organ toxicity by PHMG exposure, a toxicokinetic study must first be conducted. Howev...

  18. Analysis of Organic and Inorganic Contaminants in Dried Sewage Sludge and By-Products of Dried Sewage Sludge Gasification

    Directory of Open Access Journals (Sweden)

    Sebastian Werle

    2014-01-01

    Full Text Available Organic and inorganic contaminants in sewage sludge may cause their presence also in the by-products formed during gasification processes. Thus, this paper presents multidirectional chemical instrumental activation analyses of dried sewage sludge as well as both solid (ash, char coal and liquid (tar by-products formed during sewage gasification in a fixed bed reactor which was carried out to assess the extent of that phenomenon. Significant differences were observed in the type of contaminants present in the solid and liquid by-products from the dried sewage sludge gasification. Except for heavy metals, the characteristics of the contaminants in the by-products, irrespective of their form (solid and liquid, were different from those initially determined in the sewage sludge. It has been found that gasification promotes the migration of certain valuable inorganic compounds from sewage sludge into solid by-products which might be recovered. On the other hand, the liquid by-products resulting from sewage sludge gasification require a separate process for their treatment or disposal due to their considerable loading with toxic and hazardous organic compounds (phenols and their derivatives.

  19. Recent advances in drinking water disinfection: successes and challenges.

    Science.gov (United States)

    Ngwenya, Nonhlanhla; Ncube, Esper J; Parsons, James

    2013-01-01

    Drinking water is the most important single source of human exposure to gastroenteric diseases, mainly as a result of the ingestion of microbial contaminated water. Waterborne microbial agents that pose a health risk to humans include enteropathogenic bacteria, viruses, and protozoa. Therefore, properly assessing whether these hazardous agents enter drinking water supplies, and if they do, whether they are disinfected adequately, are undoubtedly aspects critical to protecting public health. As new pathogens emerge, monitoring for relevant indicator microorganisms (e.g., process microbial indicators, fecal indicators, and index and model organisms) is crucial to ensuring drinking water safety. Another crucially important step to maintaining public health is implementing Water Safety Plans (WSPs), as is recommended by the current WHO Guidelines for Drinking Water Quality. Good WSPs include creating health-based targets that aim to reduce microbial risks and adverse health effects to which a population is exposed through drinking water. The use of disinfectants to inactivate microbial pathogens in drinking water has played a central role in reducing the incidence of waterborne diseases and is considered to be among the most successful interventions for preserving and promoting public health. Chlorine-based disinfectants are the most commonly used disinfectants and are cheap and easy to use. Free chlorine is an effective disinfectant for bacteria and viruses; however, it is not always effective against C. parvum and G. lamblia. Another limitation of using chlorination is that it produces disinfection by-products (DBPs), which pose potential health risks of their own. Currently, most drinking water regulations aggressively address DBP problems in public water distribution systems. The DBPs of most concern include the trihalomethanes (THMs), the haloacetic acids (HAAs), bromate, and chlorite. However, in the latest edition of the WHO Guidelines for Drinking Water Quality

  20. Analysis of haloforms in wastewater. Removal of haloforms during secondary and tertiary treatment and formation during disinfection

    Energy Technology Data Exchange (ETDEWEB)

    de Leer, E W.B.

    1980-01-01

    The removal of haloforms during secondary and tertiary treatment and formation during disinfection was determined with a pentane extraction method followed by gas chromatographic separation with quantification by electron capture detection, which showed good results. High chloroform and trichloroethane levels in domestic sewage were reduced in activated-sludge tanks to 0 to 2 ..mu..g/l, one order of magnitude lower than Rotterdam drinking water.

  1. Humidifier disinfectants, unfinished stories

    Directory of Open Access Journals (Sweden)

    Yeyong Choi

    2016-02-01

    Full Text Available Once released into the air, humidifier disinfectants became tiny nano-size particles, and resulted in chemical bronchoalveolitis. Families had lost their most beloved members, and even some of them became broken. Based on an estimate of two million potential victims who had experienced adverse effects from the use of humidifier disinfectants, we can say that what we have observed was only the tip of the iceberg. Problems of entire airways, as well as other systemic effects, should be examined, as we know these nano-size particles can irritate cell membranes and migrate into systemic circulation. The story of humidifier disinfectant is not finished yet.

  2. Environmental cleaning and disinfection.

    Science.gov (United States)

    Traverse, Michelle; Aceto, Helen

    2015-03-01

    The guidelines in this article provide veterinarians, veterinary technicians, and veterinary health care workers with an overview of evidence-based recommendations for the best practices associated with environmental cleaning and disinfection of a veterinary clinic that deals with small animals. Hospital-associated infections and the control and prevention programs necessary to alleviate them are addressed from an environmental perspective. Measures of hospital cleaning and disinfection include understanding mechanisms and types of contamination in veterinary settings, recognizing areas of potential concern, addressing appropriate decontamination techniques and selection of disinfectants, the management of potentially contaminated equipment, laundry, and waste management, and environmental surveillance strategies. Copyright © 2015 Elsevier Inc. All rights reserved.

  3. Neutron activation analysis for determining of inorganic trace elements in by-products of soybean, cotton, corn, wheat, sorghum and rice

    International Nuclear Information System (INIS)

    Teruya, Carla M.; Armelin, Maria Jose; Silva Filho, Jose Cleto; Silva, Aliomar G.

    1999-01-01

    In the present paper the instrumental neutron activation analysis was applied to determine some essential and toxic elements in six agroindustrial by-products utilized to feed animal. The accuracy of the method was evaluated by means of reference material analysis. In general, the precision of the method was lower than 10% and the accuracy near to 5%. (author)

  4. Proteomic analysis of processing by-products from canned and fresh tuna: identification of potentially functional food proteins.

    Science.gov (United States)

    Sanmartín, Esther; Arboleya, Juan Carlos; Iloro, Ibon; Escuredo, Kepa; Elortza, Felix; Moreno, F Javier

    2012-09-15

    Proteomic approaches have been used to identify the main proteins present in processing by-products generated by the canning tuna-industry, as well as in by-products derived from filleting of skeletal red muscle of fresh tuna. Following fractionation by using an ammonium sulphate precipitation method, three proteins (tropomyosin, haemoglobin and the stress-shock protein ubiquitin) were identified in the highly heterogeneous and heat-treated material discarded by the canning-industry. Additionally, this fractionation method was successful to obtain tropomyosin of high purity from the heterogeneous starting material. By-products from skeletal red muscle of fresh tuna were efficiently fractionated to sarcoplasmic and myofibrillar fractions, prior to the identification based mainly on the combined searching of the peptide mass fingerprint (MALDI-TOF) and peptide fragment fingerprinting (MALDI LIFT-TOF/TOF) spectra of fifteen bands separated by 1D SDS-PAGE. Thus, the sarcoplasmic fraction contained myoglobin and several enzymes that are essential for efficient energy production, whereas the myofibrillar fraction had important contractile proteins, such as actin, tropomyosin, myosin or an isoform of the enzyme creatine kinase. Application of proteomic technologies has revealed new knowledge on the composition of important by-products from tuna species, enabling a better evaluation of their potential applications. Copyright © 2012 Elsevier Ltd. All rights reserved.

  5. Disinfection of drinking water

    International Nuclear Information System (INIS)

    Ensenauer, P.

    1977-01-01

    Some methods for disinfecting drinking water are described, e.g. UV irradiation (optimal wavelength 210-250mm) with the advantage of constant water composition and the resulting danger of re-infection. (AJ) [de

  6. Disinfection of drinking water

    Energy Technology Data Exchange (ETDEWEB)

    Ensenauer, P

    1977-01-01

    Some methods for disinfecting drinking water are described, e.g. UV irradiation (optimal wavelength 210-250mm) with the advantage of constant water composition and the resulting danger of re-infection.

  7. Biological Treatment of Water Disinfection Byproducts using ...

    Science.gov (United States)

    Major disinfection by-products (DBPs) from the chlorination process of drinking water include trihalomethanes (THMs) and haloacetic acides (HAA5). THMs mainly consist of chloroform, and other harsh chemicals. Prolonged consumptions of drinking water containing high levels of THMs has been linked with diseases of the liver, kidneys, bladder, or central nervous system and may increase likelihood of cancer. A risk also exists for THMs exposure via inhalation while showering, bathing or washing clothes and dishes. Due to these risks, the U.S. EPA regulate THMs content in drinking water. This research investigates biological degradation of THM using chloroform as a model compound. The study aims to decrease possible risks of THMs through filtration. Throughout this year’s presentations, there is a common theme of health and safety concerns. UC researchers are working hard to clean water ways of naturally occurring contaminates as well as man-made toxins found in our waterways. The significance of these presentations translates into the promise of safer environments, and more importantly saved lives, as UC’s faculty continues to produce real-world solutions to problems threatening the world around us. A biotech process has been developed and demonstrated that effectively remove and treat volatile disinfection by-products from drinking water. The process strips low concentration disinfection by-products, such as trihalomethanes, that are formed during the chlori

  8. Optimization of Chlorination Process for Mature Leachate Disinfection Using Response Surface Methodology

    Directory of Open Access Journals (Sweden)

    Hamzeh Ali Jamali1

    2014-06-01

    Full Text Available Background: leachate from landfill contains high level of microbial pathogens which is considered as one of the most important threats for the environment. One of the common and simple methods for water and wastewater disinfection is chlorination, but it rarely has been used for leachate disinfection. The objective of this study was evaluating the efficiency of chlorine for leachate disinfection and optimization of the effect of concentration and contact time on the death of total and fecal coliforms, as a microbial contamination index. Methods: In this descriptive-analysis study, microbial indices monitoring in leachates initiated from landfill of Qazvin city were conducted for one year. After pre-tests, the range of chlorine concentration and contact time on the inactivation of microbial indices were determined. Central composite design (CCD and response surface methodology (RSM were applied to optimize chlorine concentration and contact time parameters effect on microbial inactivation. 13 runs of tests were performed on samples. Tests were included BOD, COD, total and fecal coliforms. All analytical experiments were according to the standard methods for the examination of water and wastewater. Results: Results of the study showed that microbial indices had relatively high sensitivity to inactivation by chlorination, which in the chlorine concentration of 2 mg/L and contact time of 9 min, and chlorine concentration of 0.5 mg/L and contact time of 12 min, 100% of total and fecal coliforms inactivated, respectively. The RSM method was used for analysis of bacterial inactivation. Analyses showed that in contact time of 9.4 min and chlorine concentration of 2.99 mg/L, the inactivation efficiency of total and fecal coliforms were 89.16% and 100%, respectively. Conclusions: Chlorine could be used for leachate disinfection. However, in high concentrations of organic matter in leachates, due to production potential of chlorination by-products, health

  9. Effect of bioconversion conditions on vanillin production by Amycolatopsis sp. ATCC 39116 through an analysis of competing by-product formation.

    Science.gov (United States)

    Ma, Xiao-kui; Daugulis, Andrew J

    2014-05-01

    This study investigated the effects of transformation conditions such as initial pH, the initial concentration of glucose and yeast extract in the medium, and the separate addition of ferulic acid and vanillic acid, on the production of vanillin through an analysis of competing by-product formation by Amycolatopsis sp. ATCC 39116. The extent and nature of by-product formation and vanillin yield were affected by initial pH and different initial concentrations of glucose and yeast extract in the medium, with a high yield of vanillin and high cell density obtained at pH 8.0, 10 g/l glucose, and 8 g/l yeast extract. High concentrations of ferulic acid were found to negatively affect cell density. Additional supplementation of 100 mg/l vanillic acid, a metabolically linked by-product, was found to result in a high concentration of vanillin and guaiacol, an intermediate of vanillin. Via an analysis of the effect of these transformation conditions on competing by-product formation, high concentrations of ferulic acid were transformed with a molar yield to vanillin of 96.1 and 95.2 %, by Amycolatopsis sp. ATCC 39116 and Streptomyces V1, respectively, together with a minor accumulation of by-products. These are among the highest performance values reported in the literature to date for Streptomyces in batch cultures.

  10. [Analysis of Pathogenic Bacteria in Reclaimed Water and Impact of UV Disinfection on the Removal of Pathogenic Bacteria].

    Science.gov (United States)

    Jing, Ming; Wang, Lei

    2016-02-15

    In the study, 454-pyrosequencing technology was employed to investigate the species of pathogenic bacteria and the proportion of each pathogen in secondary effluent. Culture-based, qPCR and Q-RT-PCR methods were employed to analyze the removal of indicator (E. coli) and pathogen (Salmonella and Mycobacterium) by ultraviolet (UV) disinfection at a dose of 60 mJ x Cm(-2). The results showed that 11 kinds of pathogenic bacteria were found and the most abundant potentially pathogenic bacteria in the secondary effluent were affiliated with the genera of Clostridium (2.96%), Arcobacter (0.82%) and Mycobacterium (0.36%). 99.9% of culturable E. coli and Salmonella were removed by UV disinfection (60 mJ x cm(-2), however, less than 90% of culturable Mycobacterium were removed. The removal efficiencies of viable E. coli, Salmonella and Mycobacterium were low. Q-RT-PCR seemed to be a promising method for evaluating viable microorganisms in samples. Besides, pathogenic bacteria entered into VBNC state at a UV dose of 60 mJ x cm(-2). Other advanced treatment processes were needed to ensure safe utilization of reclaimed water.

  11. Chloraminated Concentrated Drinking Water for Disinfection Byproduct Mixtures Research: Evaluating Free Chlorine Contact Times

    Science.gov (United States)

    Complex mixtures of disinfection by-products (DBPs) are formed when the disinfectant oxidizes constituents (e.g., natural organic matter (NOM) and organic pollutants) present in the source water. Since 1974, over 600 DBPs have been identified in drinking water, yet a large portio...

  12. Chloramination of Concentrated Drinking Water for Disinfection Byproduct Mixtures Creation- Indianapolis

    Science.gov (United States)

    Complex mixtures of disinfection by-products (DBPs) are formed when the disinfectant oxidizes constituents (e.g., natural organic matter (NOM) and organic pollutants) found in the source water. Since 1974, over 600 DBPs have been identified in drinking water. Despite intense iden...

  13. Chloramination of Concentrated Drinking Water: Evaluation of Disinfection Byproduct Formation and Dosing Scenarios - Portland

    Science.gov (United States)

    Complex mixtures of disinfection by-products (DBPs) are formed when the disinfectant oxidizes constituents (e.g., natural organic matter (NOM) and organic pollutants) found in the source water. Since 1974, over 600 DBPs have been identified in drinking water. Despite intense iden...

  14. Bench-Scale Evaluation of Peracetic Acid and Twin Oxide ™ as Disinfectants in Drinking Water

    Science.gov (United States)

    Chlorine is widely used as an inexpensive and potent disinfectant in the United States for drinking water. However, chlorine has the potential for forming carcinogenic and mutagenic disinfection by-products (DBPs). In this study, bench scale experiments were conducted at the U.S...

  15. Emergency Disinfection of Drinking Water

    Science.gov (United States)

    How to boil and disinfect water to kill most disease-causing microorganisms during emergency situations where regular water service has been interrupted and local authorities recommend using only bottled water, boiled water, or disinfected water.

  16. Biogas production from animal manure and agri-organic by-products. An analysis of the environment

    International Nuclear Information System (INIS)

    De Boo, W.

    1997-12-01

    Growing interest in sustainable energy has been directed to the production of biogas from organic matter in animal manure and agri-organic by-products. The technology of biogas production by anaerobic digestion of organic materials is used in several parts of the world. Based on this experience and on positive results in a Novem study for the Netherlands situation in 1995, an actor survey has been carried out. The introduction of combined digestion of animal manure and agri-organic by-products has been discussed with companies, business associations and governmental organisations in the energy, agricultural and waste sectors. The survey has revealed that commercial exploitation of biogas plants with a capacity of 100 kton per year is possible under the following conditions: (1) costs of investment should not be higher than 100 Dutch Guilders (45 ECU) per ton processing capacity; (2) yield demands on investment capital, both equity and debt, should not be higher than 8%; (3) selling price for biogas should be around 0,30 Dutch Guilders (0,135 ECU) per m o 3 natural gas equivalents; (4) supply for processing of agri-organic by-products with a received minimum fee of 35 Dutch Guilders (15,7 ECU) per ton should be guaranteed; (5) dairy, pig and arable farmers involved in the biogas plant should have both financial and quality incentives to participation; (6) environmental legislation on the level of heavy metals in animal manure mixed with agri-organic byproducts should not be different from the accepted levels in 'normal' animal manure; and finally (7) the site of the biogas plant accepted by local authorities should be suitable by logistic standards for the transports of animal manure, agri-organic by-products, the digested mixture and biogas. It has been concluded that these conditions are not unrealistic, although there is no absolute certainty that they will be fulfilled. However, circumstances for the implementation of biogas plants have improved in recent years

  17. Regulatory impact analysis of national emissions standards for hazardous air pollutants for by-product coke oven charging, door leaks, and topside leaks. Draft report

    International Nuclear Information System (INIS)

    1992-11-01

    Under the authority of the 1990 Clean Air Act Amendments, a Natioal Emissions Standard for Hazardous Air Pollutants is proposed to control emissions from By-product Coke Oven Charging, door leaks, and topside leaks. Because the EPA considers the regulation for By-product Coke Oven batteries to be a major rule, the attached Regulatory Impact Analysis was prepared to fulfill the requirements of E012291. The document reviews the need for regulation, control techniques, regulatory options, costs of control, economic impacts, benefits of the regulation, and compares benefits and costs associated with the regulation

  18. Greenhouse gas emissions from first generation ethanol derived from wheat and sugar beet in Germany – Analysis and comparison of advanced by-product utilization pathways

    International Nuclear Information System (INIS)

    Weinberg, Jana; Kaltschmitt, Martin

    2013-01-01

    Highlights: ► Ethanol production from sugar beet and wheat is investigated. ► Instead of feed production from residues by-products are used for energy production. ► Ethanol from sugar beet with biogas co-production shows lowest GHG emissions. ► For wheat pathways bran and gluten separation generates lowest GHG emissions. ► An allocation method is recommended involving co-produced fertilizer. -- Abstract: In state of the art ethanol production, by-products like vinasse from sugar beet or distiller’s dried grains with solubles (DDGSs) from wheat grains are usually used as animal feed. The drying process consumes a significant amount of energy that could be reduced by producing other valuable materials or energy carriers from these by-products. Besides resulting higher overall conversion rates and improved process efficiencies, by-products, which can be extracted or are automatically created during the various conversion steps, should be used to reduce environmental impacts as well. In this analysis, advanced pathways for the recovery and use of by-products from bio-chemical ethanol production like gluten separation from wheat starch, biogas production from stillage or vinasse and combustion of bran for electricity generation are analyzed with regard to their contribution to the greenhouse effect. Therefore, different methodological approaches are applied and compared. The analysis shows among others that ethanol from sugar beet generates less greenhouse gases (GHGs) compared to the ethanol production from wheat. The biogas production from residues and especially the use of bran for heat and electricity generation shows significant GHG reduction compared to the state of the art application. However, the methodological approach for the treatment of by-products highly influences the results. For the reproducibility of the results an energy equivalent allocation method involving the specific application of the respective co-product is recommended.

  19. Disinfection by electrohydraulic treatment.

    Science.gov (United States)

    Allen, M; Soike, K

    1967-04-28

    Electrohydraulic treatment was applied to suspensions of Escherichia coli, spores of Bacillus subtilis var. niger, Saccharomyces cerevisiae, and bacteriophage T2 at an input energy that, in most cases, was below the energy required to sterilize. The input energy was held relatively constant for each of these microorganisms, but the capacitance and voltage were varied. Data are presented which show the degree of disinfection as a function of capacitance and voltage. In all cases, the degree of disinfection for a given input energy increases as both capacitance and voltage are lowered.

  20. UV disinfection of water

    International Nuclear Information System (INIS)

    Skipperud, E.; Johansen; Myhrstad, J.A.

    1978-01-01

    UV radiation has been found to have advantages over chloration for the disinfection of water. New regulations for dietary conditions on Norwegian ships introduced in 1974 led to increased use of UV disinfection, and this has in the following years spread to waterworks. The present article is based on a study to determine possible limitation. The nature of the injuries to the microorganisms is first discussed, together with repair mechanisms. A table is given showing the energy required for 90 and 100 percent inactivation of a number of microorganisms. Some other factors affecting UV inactivation are briefly mentioned. (JIW)

  1. Effect of selection of pH in swimming pool on formation of chlorination by-products

    DEFF Research Database (Denmark)

    Hansen, Kamilla Marie Speht; Willach, Sarah; Mosbæk, Hans

    2011-01-01

    Chlorine is used as disinfection agent in public swimming pools, but also reacts with organic matter in the water forming chlorinat ed disinfection by-products. In order to evaluate the effect of choice of pHsetpoint in the pool we investigated the effect of chlorination of artificial body fluid...

  2. Disinfection of sewage

    International Nuclear Information System (INIS)

    Arenas, J.

    1984-01-01

    Laboratory studies at IPEN and SEDAPAL have shown the effectiveness disinfection of sewage by means of ionizing radiations. A dose of 1 Kilo Gray reduces the coliforms and salmonella under the permissible levels. This method should allow to use again the liquids in the agriculture or its disposal like sea nutrient

  3. Investigation on by-products of bioenergy systems (anaerobic digestion and gasification) as potential crop nutrient using FTIR, XRD, SEM analysis and phyto-toxicity test.

    Science.gov (United States)

    Kataki, Sampriti; Hazarika, Samarendra; Baruah, D C

    2017-07-01

    Success and acceptability of the bio energy conversion technology to a large extent depend upon management of the inevitable by-products generated during the conversion process. By-products can be considered favourable as organic fertilizer as they retain nutrients with varying composition depending upon input biomass. However, characteristics of these heterogeneous resources with respect to feedstock and processing conditions have to be assessed to state on their agricultural and environmental benefits. Therefore, 3 types of anaerobic digestion by-products (digestate) from surplus biomass viz. cow dung, Ipomoea carnea:cow dung (60:40 dry weight basis) and rice straw:green gram stover:cow dung (30:30:40 dry weight basis) and one gasification by-product (biochar) from rice husk are considered to understand the fertilizer prospects. Considering 3 potential application options, digestate from each feedstock option was further processed as separated solid, separated liquid and ash from solid digestates. Thus, a total of 10 by-products were investigated for understanding their prospects as fertilizer using Fourier Transform Infrared Spectroscopy (FTIR), X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) and Energy Dispersive X ray Spectroscopy (EDX) and phyto-toxicity test to have a broad insight in terms of their organic, mineral, elemental composition, morphological feature and potential phyto-toxicity. In general, irrespective of origin of feedstock, solid digestate, ash digestate and char showed similarity in terms of composition of functional groups with some degree of variation in relative content as reflected by FTIR analysis. Dominance of organic functional groups in separated solid digestates compared to liquid fraction indicated the former as favourable organic amendments. Quartz was the prevalent mineral phase in all separated solid, ash digestate and rice husk char. Digestates in ash phase represent more concentrated plant nutrient source with

  4. Application of Neutron Activation Analysis to the determination of essential and toxic elements in agroindustrial by-products employed in animal feeding

    International Nuclear Information System (INIS)

    Teruya, Carla Mitie

    1999-01-01

    In the present work the concentrations of essential elements Ca (calcium), CI (chlorine), K (potassium), Mg (magnesium), Na (sodium), Co (cobalt), Cr (chromium), Cu (copper), Fe (iron), Mn (manganese). Mo (molybdenum), Se (selenium), V (vanadium) and Zn (zinc), the toxic elements As (arsenic), Cd (cadmium) and Hg (mercury) and the elements without defined functions to the animal metabolism, such as Br (bromine), Eu (europium). La (lanthanum), Rb (rubidium), Sb (antinomies), Sc (scandium), Ta (tantalum), Th (thorium) and U (uranium) were determined in agroindustrial by-products employed in animal feeding by instrumental neutron activation analysis (INAA). Forty samples of agroindustrial by-products were analyzed, six of which are from animal origin and the others are from vegetable origin. All these materials are widely used in bovine feeding, mainly in dry season, when the forage become scarce. The precision and accuracy of the method were evaluated by means of analysis of the following certified reference materials: Rice Flour NIES-CRM-10C, Pig Kidney BCR-CRM, Oyster Tissue NIST-SRM-1566a e Buffalo River Sediment NIST-SRM-2704. The results, in general, are lower than 10 %. The results for the most of essential minerals were lower than the toxic limit for animals, and they reached the minimum requirements for domestic animals, although some agroindustrial by-products showed concentrations lower than the requirement. For all samples, the concentrations of toxic minerals were lower than the toxic limit (author)

  5. Does disinfection of environmental surfaces influence nosocomial infection rates? A systematic review.

    Science.gov (United States)

    Dettenkofer, Markus; Wenzler, Sibylle; Amthor, Susanne; Antes, Gerd; Motschall, Edith; Daschner, Franz D

    2004-04-01

    To review the evidence on the effects of disinfection of environmental surfaces in hospitals (as compared with cleaning without use of disinfectants) on the occurrence of nosocomial infections. Systematic review of experimental and nonexperimental intervention studies dealing with environmental disinfection or cleaning in different health care settings. A total of 236 scientific articles were identified. None described a meta-analysis, systematic review, or randomized controlled trial. Only 4 articles described completed cohort studies matching the inclusion criteria. None of these studies showed lower infection rates associated with routine disinfection of surfaces (mainly floors) versus cleaning with detergent only. Disinfectants may pose a danger to staff, patients, and the environment and require special safety precautions. However, targeted disinfection of certain environmental surfaces is in certain instances an established component of hospital infection control. Given the complex, multifactorial nature of nosocomial infections, well-designed studies that systematically investigate the role of surface disinfection are required.

  6. Comparison of full-mouth disinfection and quadrant-wise scaling in the treatment of adult chronic periodontitis: a systematic review and meta-analysis.

    Science.gov (United States)

    Fang, H; Han, M; Li, Q-L; Cao, C Y; Xia, R; Zhang, Z-H

    2016-08-01

    Scaling and root planing are widely considered as effective methods for treating chronic periodontitis. A meta-analysis published in 2008 showed no statistically significant differences between full-mouth disinfection (FMD) or full-mouth scaling and root planing (FMS) and quadrant scaling and root planing (Q-SRP). The FMD approach only resulted in modest additional improvements in several indices. Whether differences exist between these two approaches requires further validation. Accordingly, a study was conducted to further validate whether FMD with antiseptics or FMS without the use of antiseptics within 24 h provides greater clinical improvement than Q-SRP in patients with chronic periodontitis. Medline (via OVID), EMBASE (via OVID), PubMed and CENTRAL databases were searched up to 27 January 2015. Randomized controlled trials comparing FMD or FMS with Q-SRP after at least 3 mo were included. Meta-analysis was performed to obtain the weighted mean difference (WMD), together with the corresponding 95% confidence intervals. Thirteen articles were included in the meta-analysis. The WMD of probing pocket depth reduction was 0.25 mm (p chronic periodontitis, and they do not lead to any obvious discomfort among patients. Moreover, FMD had modest additional clinical benefits over Q-SRP, so we prefer to recommend FMD as the first choice for the treatment of adult chronic periodontitis. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  7. Sewage sludges disinfection

    International Nuclear Information System (INIS)

    Alexandre, D.; Gevaudan, P.P.

    1977-01-01

    There is a hygienic risk in using biological sewage sludges for agriculture. Systematic analyses carried out on sludge samples obtained from purification plants in the Eastern and Southern part of France, show the almost uniform presence of pathogenic microorganisms. Some of them survive more than nine months after application to the soil. Conventional processes for disinfection, liming and heat, make the sludge unsuitable for agricultural use. On the other hand, irradiation involves no modification of structure and composition of sludges. Radiation doses required for disinfection vary according to the type of microorganism. Some of them are eliminated at rather low doses (200 krad), but mycobacteria, viruses and eggs of worms resist to more important doses. The security dose is estimated to be approx. 1000 krad

  8. Spiral-shaped reactor for water disinfection

    KAUST Repository

    Soukane, Sofiane; Ait-Djoudi, Fariza; Naceur, Wahib M.; Ghaffour, NorEddine

    2016-01-01

    Chlorine-based processes are still widely used for water disinfection. The disinfection process for municipal water consumption is usually carried out in large tanks, specifically designed to verify several hydraulic and disinfection criteria

  9. Wettability changes in polyether impression materials subjected to immersion disinfection.

    Science.gov (United States)

    Shetty, Shweta; Kamat, Giridhar; Shetty, Rajesh

    2013-07-01

    Disinfection of impression materials prevents cross-contamination; however, the disinfectants may alter the wettability property. The purpose of this investigation was to evaluate the wettability changes of polyether impression material after immersing in four different chemical disinfectant solutions for a period of 10 min and 30 min, respectively. A total of 45 samples of polyether dental impression material (Impregum soft, 3MESPE, St. Paul, MN, USA) were randomly divided into nine groups with five specimens each. Each specimen was disc shaped, flat of 32 mm diameter and 3 mm thickness. The samples were immersed in four disinfectant solutions: 2% Glutaraldehyde, 5% sodium hypochlorite, 0.05% iodophor, and 5.25% phenol for 10 min and 30 min, respectively. The control was without disinfection. Wettability of the samples was assessed by measuring the contact angle by using the Telescopic Goniometer. Data were subjected to analysis of variance (Fisher's test) and Tukey's post hoc test for multiple comparisons at 5% level of significance. The contact angle of 20.21° ± 0.22° were recorded in the control samples. After 10 min, the samples that were immersed in 5% sodium hypochlorite and 5.25% phenol showed significant statistical increase in the contact angle as compared to the control (P polyether material. Within the limitations of the study, 2% glutaraldehyde proved safe for 10 min of immersion disinfection while 0.05% iodophor holds promise as an effective disinfectant without affecting the wettability of the material.

  10. Carbon nanoparticles for solar disinfection of water.

    Science.gov (United States)

    Maddigpu, Pratap Reddy; Sawant, Bhairavi; Wanjari, Snehal; Goel, M D; Vione, Davide; Dhodapkar, Rita S; Rayalu, S

    2018-02-05

    The present manuscript deals with the application of carbon nano particles (CNP) and chitosan (CHIT) in the form of CHIT-CNP composite for the disinfection of water. The CHIT-CNP composite was prepared by the solution casting method and characterized by TEM, XRD and elemental analysis. In the present investigation we study the disinfection efficiency towards E. coli bacteria of both CNP and CHIT-CNP, under sunlight (SODIS) in identical experimental conditions. Both CNP and CHIT-CNP enhanced disinfection as compared to SODIS alone, and comparable performance was achieved when the same dose of CNP in the two materials was applied. However, the CHIT-CNP composite is in the form of a fabric and it is easier to use and handle as compared to the CNP powder, especially in rural and resource-constrained areas. Moreover the SODIS-CHIT-CNP setup, when used in a compound parabolic collector (CPC) reactor showed high bactericidal efficiency compared to SODIS alone, which is promising for practical applications. The disinfection potential of the CNP powder was compared with that of the well-known material TiO 2 Degussa P25 (DP 25 ): DP 25 gave 6-log kill of bacteria in 180min, whereas CNP produced 6-log kill in 150min. Copyright © 2017. Published by Elsevier B.V.

  11. A review on wastewater disinfection

    Directory of Open Access Journals (Sweden)

    Mohammad Mehdi Amin

    2013-01-01

    Full Text Available Changes in regulations and development of new technologies have affected the selection of alternative for treated wastewater disinfection. Disinfection is the last barrier of wastewater reclamation process to protect ecosystem safety and human health. Driving forces include water scarcity and drinking water supply, irrigation, rapid industrialization, using reclaimed water, source protection, overpopulation, and environmental protection. The safe operation of water reuse depends on effluent disinfection. Understanding the differences in inactivation mechanisms is critical to identify rate-limiting steps involved in the inactivation process as well as to develop more effective disinfection strategies. Disinfection byproducts discharged from wastewater treatment plants may impair aquatic ecosystems and downstream drinking-water quality. Numerous inorganic and organic micropollutants can undergo reactions with disinfectants. Therefore, to mitigate the adverse effects and also to enhance that efficiency, the use of alternative oxidation/disinfection systems should be evaluated as possible alternative to chlorine. This review gives a summary of the traditional, innovative, and combined disinfection alternatives and also disinfection byproducts for effluent of municipal wastewater treatment plants.

  12. Sanitizers and Disinfectants Guide. Revised

    Science.gov (United States)

    Healthy Schools Network, Inc., 2012

    2012-01-01

    Sanitizers and disinfectants can play an important role in protecting public health. They are designed to kill "pests," including infectious germs and other microorganisms such as bacteria, viruses, and fungi. Unfortunately, sanitizers and disinfectants also contain chemicals that are "pesticides." Exposure to persistent toxic…

  13. The Effect of Disinfection by Spray Atomization on Dimensional Accuracy of Condensation Silicone Impressions

    Directory of Open Access Journals (Sweden)

    Fariba Saleh Saber

    2010-12-01

    Full Text Available Background and aims. The condensation silicone impression materials are available, but there is little knowledge of their accuracy after disinfection. The objective of this study was to evaluate the effect of the disinfection by spray atomization on dimensional accuracy of condensation silicone impressions. Materials and methods. Impressions were made on a stainless steel master model containing a simulated two complete crown preparation with an edentulous space interposed using Spidex® and Rapid® impression materials. 44 impressions were made with each material, of which 16 were disinfected with 5.25% sodium hypochlorite, 16 were disinfected with 10% iodophor and 12 were not disinfected. Three dimensional measurements of working casts, including interpreparation distance, height, and diameter, were calculated using a measuring microscope graduated at 0.001 mm. Dimensional changes (mm between the disinfected and non-disinfected working casts were compared. One-way analysis of variance (ANOVA was employed to analyze the data (α=0.05. Results. Disinfection of each condensation silicone material by spraying atomization with two different disinfectant material resulted in significant change in interpreparation distance (p<0.05. Changes in height and diameter were only significant in Spidex® impressions (p<0.05. Conclusion. Significant changes in the mean dimensions were seen as a result of disinfection by spraying; however, the dimensional changes do not seem great enough to cause critical positional distortion of teeth when fixed partial denture restorations are made.

  14. 40 CFR 141.72 - Disinfection.

    Science.gov (United States)

    2010-07-01

    ... PRIMARY DRINKING WATER REGULATIONS Filtration and Disinfection § 141.72 Disinfection. A public water... the direct influence of surface water and provides filtration treatment must provide disinfection...) Disinfection requirements for public water systems which provide filtration. Each public water system that...

  15. A review on wastewater disinfection

    OpenAIRE

    Mohammad Mehdi Amin; Hassan Hashemi; Amir Mohammadi Bovini; Yung Tse Hung

    2013-01-01

    Changes in regulations and development of new technologies have affected the selection of alternative for treated wastewater disinfection. Disinfection is the last barrier of wastewater reclamation process to protect ecosystem safety and human health. Driving forces include water scarcity and drinking water supply, irrigation, rapid industrialization, using reclaimed water, source protection, overpopulation, and environmental protection. The safe operation of water reuse depends on effluent d...

  16. Association of high-level humidifier disinfectant exposure with lung injury in preschool children.

    Science.gov (United States)

    Park, Dong-Uk; Ryu, Seung-Hun; Roh, Hyun-Suk; Lee, Eun; Cho, Hyun-Ju; Yoon, Jisun; Lee, So-Yeon; Cho, Young Ah; Do, Kyung-Hyun; Hong, Soo-Jong

    2018-03-01

    Children aged ≤6years reportedly account for 52% of victims of humidifier disinfectant-associated lung injuries. To evaluate the association of humidifier disinfectants with lung injury risk among children aged ≤6years. Patients with humidifier disinfectant-associated lung injuries (n=214) who were clinically evaluated to have a definite (n=108), probable (n=49), or possible (n=57) association with humidifier disinfectants as well as control patients (n=123) with lung injury deemed unlikely to be associated with humidifier disinfectant use were evaluated to determine factors associated with increased risk of humidifier disinfectant-associated lung injury using unconditional multiple logistic regression analysis. For estimated airborne humidifier disinfectant concentrations, risk of humidifier disinfectant-associated lung injury increased ≥two-fold in a dose-dependent manner in the highest quartile (Q4, 135-1443μg/m 3 ) compared with that in the lowest quartile (Q1, ≤33μg/m 3 ). Registered patients using more than two humidifier disinfectant brands were at an increased risk of humidifier disinfectant-associated lung injury (adjusted OR, 2.2; 95% confidence interval, 1.3-3.8) compared with those using only one brand. With respect to the duration of humidifier disinfectant use, risk of humidifier disinfectant-associated lung injury increased ≥two-fold in the lowest quartile (≤5months) compared with that in the highest quartile (≥14months; adjusted OR 0.3; 95% confidence interval, 0.2-0.6). Younger children are more vulnerable to HDLI when exposed to HD chemicals within short period in early life. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. In Vitro Evaluation of Dimensional Stability of Alginate Impressions after Disinfection by Spray and Immersion Methods

    Directory of Open Access Journals (Sweden)

    Fahimeh Hamedi Rad

    2010-12-01

    Full Text Available Background and aims. The most common method for alginate impression disinfection is spraying it with disinfecting agents, but some studies have shown that these impressions can be immersed, too. The aim of this study was to evaluate the dimensional stability of alginate impressions following disinfecting by spray and immersion methods. Materials and methods. Four common disinfecting agents (Sodium Hypochlorite, Micro 10, Glutaraldehyde and Deconex were selected and the impressions (n=108 were divided into four groups (n=24 and eight subgroups (n=12 for disinfecting by any of the four above-mentioned agents by spray or immersion methods. The control group (n=12 was not disinfected. Then the impressions were poured by type III Dental Stone Plaster in a standard method. The results were analyzed by descriptive methods (mean and standard deviation, t-test, two-way analysis of variance (ANOVA and Duncan test, using SPSS 14.0 software for windows. Results. The mean changes of length and height were significant between the various groups and disinfecting methods. Regarding the length, the greatest and the least amounts were related to Deconex and Micro 10 in the immersion method, respectively. Regarding height, the greatest and the least amounts were related to Glutaraldehyde and Deconex in the immersion method, respectively. Conclusion. Disinfecting alginate impressions by Sodium Hypochlorite, Deconex and Glutaraldehyde by immersion method is not recommended and it is better to disinfect alginate impressions by spraying of Micro 10, Sodium Hypochlorite, Glutaraldehyde and immersion in Micro 10.

  18. Volatile Composition and Enantioselective Analysis of Chiral Terpenoids of Nine Fruit and Vegetable Fibres Resulting from Juice Industry By-Products

    Directory of Open Access Journals (Sweden)

    Alexis Marsol-Vall

    2017-01-01

    Full Text Available Fruit and vegetable fibres resulting as by-products of the fruit juice industry have won popularity because they can be valorised as food ingredients. In this regard, bioactive compounds have already been studied but little attention has been paid to their remaining volatiles. Considering all the samples, 57 volatiles were identified. Composition greatly differed between citrus and noncitrus fibres. The former presented over 90% of terpenoids, with limonene being the most abundant and ranging from 52.7% in lemon to 94.0% in tangerine flesh. Noncitrus fibres showed more variable compositions, with the predominant classes being aldehydes in apple (57.5% and peach (69.7%, esters (54.0% in pear, and terpenoids (35.3% in carrot fibres. In addition, enantioselective analysis of some of the chiral terpenoids present in the fibre revealed that the enantiomeric ratio for selected compounds was similar to the corresponding volatile composition of raw fruits and vegetables and some derivatives, with the exception of terpinen-4-ol and α-terpineol, which showed variation, probably due to the drying process. The processing to which fruit residues were submitted produced fibres with low volatile content for noncitrus products. Otherwise, citrus fibres analysed still presented a high volatile composition when compared with noncitrus ones.

  19. Environmentally friendly disinfectant: Production, disinfectant action and efficiency

    Directory of Open Access Journals (Sweden)

    Čekerevac Milan I.

    2006-01-01

    Full Text Available Silver is a known disinfectant from ancient times, and it has been widely used for various purposes: for food and water disinfection, curing of wounds and as a universal antibiotic for a wide spectrum of diseases - until the Second World War and the discovery of penicillin. Until recently, it was assumed that silver, being a heavy metal, was toxic for humans and living beings. However, the newest research provides facts that the usage of silver, even for drinking water disinfection, is benign if it is added in small concentrations (in parts per billion. It has been shown in the newer scientific and technical literature that silver in colloidal form is a powerful (secondary disinfectant for drinking water, that it can be effectively used for the disinfection of water containers including swimming pools, installations in food industry, medicine, etc. Particularly, it has been shown that colloidal silver combined with hydrogen peroxide shows synergism having strong bactericidal and antiviral effects. The combination can be successfully used as a disinfectant in agriculture, food production and medicine. The original electrochemical process of production, the mechanism of physical-chemical reactions in that process and the mechanism of the antiseptic affect of the environmentally friendly disinfectant, based on the synergism of colloidal silver and hydrogen peroxide and the activity of electrochemically activated water, is shown. The starting solution was anolyte, obtained in electrochemical activation by water electrolysis of a highly diluted solution of K-tartarate in demineralized water (5.5-1CT4 M. The problem of electrolysis of very dilute aqueous solutions in membrane cells was particularly treated. It was shown that the efficiency of the electrolysis depends on the competition between the two processes: the rates of the processes of hydrogen and oxygen generation at the electrodes and the process of diffusion of hydrogen and hydroxyl ions

  20. Disinfection Pilot Trial for Little Miami WWTP | Science ...

    Science.gov (United States)

    There is a serious interest growing nationally towards the use of PAA at various stages of public waste water treatment facilities; one of such use is secondary waste water treatment. MSDGC is currently interested in improving efficiency and economic aspects of waste water treatment. MSDGC requested for ORD’s support to evaluate alternative cost-effective disinfectants. This report herein is based on the data generated from the field pilot test conducted at the Little Miami Wastewater Treatment Plant. Chlorine assisted disinfection of wastewaters created the concern regarding the formation of high levels of toxic halogenated disinfection byproducts (DBPs) detrimental to aquatic life and public health. Peracetic acid is emerging as a green alternative to chlorine and claimed to have economic and social benefits. In addition, it is a relatively simple retrofit to the existing chlorine treated wastewater treatment facilities. PAA is appealed to possess a much lower aquatic toxicity profile than chlorine and decays rapidly in the environment, even if overdosed. As a result, PAA generally does not need a quenching step, such as dechlorination, reducing process complexity, sodium pollution and cost. PAA treatment does not result in the formation of chlorinated disinfection by-products such as trihalomethanes (THMs), haloacetic acids and other byproducts such as cyanide and n-Nitrosodimethylamine (NDMA).

  1. Disinfection of wastewater with peracetic acid: a review.

    Science.gov (United States)

    Kitis, Mehmet

    2004-03-01

    Peracetic acid is a strong disinfectant with a wide spectrum of antimicrobial activity. Due to its bactericidal, virucidal, fungicidal, and sporicidal effectiveness as demonstrated in various industries, the use of peracetic acid as a disinfectant for wastewater effluents has been drawing more attention in recent years. The desirable attributes of peracetic acid for wastewater disinfection are the ease of implementing treatment (without the need for expensive capital investment), broad spectrum of activity even in the presence of heterogeneous organic matter, absence of persistent toxic or mutagenic residuals or by-products, no quenching requirement (i.e., no dechlorination), small dependence on pH, short contact time, and effectiveness for primary and secondary effluents. Major disadvantages associated with peracetic acid disinfection are the increases of organic content in the effluent due to acetic acid (AA) and thus in the potential microbial regrowth (acetic acid is already present in the mixture and is also formed after peracetic acid decomposition). Another drawback to the use of peracetic acid is its high cost, which is partly due to limited production capacity worldwide. However, if the demand for peracetic acid increases, especially from the wastewater industry, the future mass production capacity might also be increased, thus lowering the cost. In such a case, in addition to having environmental advantages, peracetic acid may also become cost-competitive with chlorine.

  2. Demonstration of disinfection procedure for the development of accurate blood glucose meters in accordance with ISO 15197:2013

    Science.gov (United States)

    Lin, Wen-Ye; Chang, Jung-Tzu; Chu, Chun-Feng

    2017-01-01

    Despite measures to reduce disease transmission, a risk can occur when blood glucose meters (BGMs) are used on multiple individuals or by caregivers assisting a patient. The laboratory and in-clinic performance of a BGM system before and after disinfection should be demonstrated to guarantee accurate readings and reliable control of blood glucose (BG) for patients. In this study, an effective disinfection procedure, conducting wiping 10 times to assure a one minute contact time of the disinfectant on contaminated surface, was first demonstrated using test samples of the meter housing materials, including acrylonitrile butadiene styrene (ABS), polymethyl methacrylate (PMMA), and polycarbonate (PC), in accordance with ISO 15197:2013. After bench studies comprising 10,000 disinfection cycles, the elemental compositions of the disinfected ABS, PMMA, and PC samples were almost the same as in the original samples, as indicated by electron spectroscopy for chemical analysis. Subsequently, the validated disinfection procedure was then directly applied to disinfect 5 commercial BGM systems composed of ABS, PMMA, or PC to observe the effect of the validated disinfection procedure on meter accuracy. The results of HBsAg values after treatment with HBV sera and disinfectant wipes for each material were less than the LoD of each material of 0.020 IU/mL. Before and after the multiple disinfection cycles, 900 of 900 samples (100%) were within the system accuracy requirements of ISO 15197:2013. All of the systems showed high performance before and after the series of disinfection cycles and met the ISO 15197:2013 requirements. In addition, our results demonstrated multiple cleaning and disinfection cycles that represented normal use over the lifetime of a meter of 3–5 years. Our validated cleaning and disinfection procedure can be directly applied to other registered disinfectants for cleaning commercial BGM products in the future. PMID:28683148

  3. [DESIDENT CaviCide a new disinfectant].

    Science.gov (United States)

    Severa, J; Klaban, V

    2009-01-01

    The properties of the new disinfection agent DESIDENT CaviCide, such as characteristics, disinfection efficiency, biological degradability and ecotoxicity are described. Also areas and forms of usage this biocidal agent are mentioned.

  4. Clinical and cost effectiveness of eight disinfection methods for terminal disinfection of hospital isolation rooms contaminated with Clostridium difficile 027.

    Science.gov (United States)

    Doan, L; Forrest, H; Fakis, A; Craig, J; Claxton, L; Khare, M

    2012-10-01

    Clostridium difficile spores can survive in the environment for months or years, and contaminated environmental surfaces are important sources of nosocomial C. difficile transmission. To compare the clinical and cost effectiveness of eight C. difficile environmental disinfection methods for the terminal cleaning of hospital rooms contaminated with C. difficile spores. This was a novel randomized prospective study undertaken in three phases. Each empty hospital room was disinfected, then contaminated with C. difficile spores and disinfected with one of eight disinfection products: hydrogen peroxide vapour (HPV; Bioquell Q10) 350-700 parts per million (ppm); dry ozone at 25 ppm (Meditrox); 1000 ppm chlorine-releasing agent (Actichlor Plus); microfibre cloths (Vermop) used in combination with and without a chlorine-releasing agent; high temperature over heated dry atomized steam cleaning (Polti steam) in combination with a sanitizing solution (HPMed); steam cleaning (Osprey steam); and peracetic acid wipes (Clinell). Swabs were inoculated on to C. difficile-selective agar and colony counts were performed pre and post disinfection for each method. A cost-effectiveness analysis was also undertaken comparing all methods to the current method of 1000 ppm chlorine-releasing agent (Actichlor Plus). Products were ranked according to the log(10) reduction in colony count from contamination phase to disinfection. The three statistically significant most effective products were hydrogen peroxide (2.303); 1000 ppm chlorine-releasing agent (2.223) and peracetic acid wipes (2.134). The cheaper traditional method of using a chlorine-releasing agent for disinfection was as effective as modern methods. Copyright © 2012 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

  5. Estimating retrospective exposure of household humidifier disinfectants.

    Science.gov (United States)

    Park, D U; Friesen, M C; Roh, H S; Choi, Y Y; Ahn, J J; Lim, H K; Kim, S K; Koh, D H; Jung, H J; Lee, J H; Cheong, H K; Lim, S Y; Leem, J H; Kim, Y H; Paek, D M

    2015-12-01

    We conducted a comprehensive humidifier disinfectant exposure characterization for 374 subjects with lung disease who presumed their disease was related to humidifier disinfectant use (patient group) and for 303 of their family members (family group) for an ongoing epidemiological study. We visited the homes of the registered patients to investigate disinfectant use characteristics. Probability of exposure to disinfectants was determined from the questionnaire and supporting evidence from photographs demonstrating the use of humidifier disinfectant, disinfectant purchase receipts, any residual disinfectant, and the consistency of their statements. Exposure duration was estimated as cumulative disinfectant use hours from the questionnaire. Airborne disinfectant exposure intensity (μg/m(3)) was estimated based on the disinfectant volume (ml) and frequency added to the humidifier per day, disinfectant bulk level (μg/ml), the volume of the room (m(3)) with humidifier disinfectant, and the degree of ventilation. Overall, the distribution patterns of the intensity, duration, and cumulative exposure to humidifier disinfectants for the patient group were higher than those of the family group, especially for pregnant women and patients ≤6 years old. Further study is underway to evaluate the association between the disinfectant exposures estimated here with clinically diagnosed lung disease. Retrospective exposure to household humidifier disinfectant as estimated here can be used to evaluate associations with clinically diagnosed lung disease due to the use of humidifier disinfectant in Korea. The framework, with modifications to account for dispersion and use patterns, can also be potentially adapted to assessment of other household chemical exposures. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  6. Microbiological Efficacy Test Methods of Disinfectants

    OpenAIRE

    Şahiner, Aslı

    2015-01-01

    Disinfection process is required in every area where microbiological contamination and infection risk is present, especially in medical sector, food, veterinary and general common living areas hence many disinfectants and antiseptics are being produced for different purposes. Disinfectants are made up a large group of biocidal products. Depending on the chemical properties of active substances, targeted microorganisms may differ While some disinfectants are effective in a large spectrum, othe...

  7. UV disinfection in drinking water supplies.

    Science.gov (United States)

    Hoyer, O

    2000-01-01

    UV disinfection has become a practical and safely validatable disinfection procedure by specifying the requirements for testing and monitoring in DVGW standard W 294. A standardized biodosimetric testing procedure and monitoring with standardized UV sensors is introduced and successfully applied. On-line monitoring of irradiance can be counterchecked with handheld reference sensors and makes it possible that UV systems can be used for drinking water disinfection with the same level of confidence and safety as is conventional chemical disinfection.

  8. Can pulsed xenon ultraviolet light systems disinfect aerobic bacteria in the absence of manual disinfection?

    Science.gov (United States)

    Jinadatha, Chetan; Villamaria, Frank C; Ganachari-Mallappa, Nagaraja; Brown, Donna S; Liao, I-Chia; Stock, Eileen M; Copeland, Laurel A; Zeber, John E

    2015-04-01

    Whereas pulsed xenon-based ultraviolet light no-touch disinfection systems are being increasingly used for room disinfection after patient discharge with manual cleaning, their effectiveness in the absence of manual disinfection has not been previously evaluated. Our study indicates that pulsed xenon-based ultraviolet light systems effectively reduce aerobic bacteria in the absence of manual disinfection. These data are important for hospitals planning to adopt this technology as adjunct to routine manual disinfection. Published by Elsevier Inc.

  9. Biochemical and physicochemical analysis of fish protein isolate recovered from red snapper (Lutjanus sp.) by-product using isoelectric solubilization/precipitation method

    Science.gov (United States)

    Pramono, H.; Pujiastuti, D. Y.; Sahidu, A. M.

    2018-04-01

    The effect of acid- and alkali-process on biochemical and physicochemical characteristics of fish protein isolate from red snapper (Lutjanus sp) by-product was evaluated. Protein recovered by alkali process (16.79%) was higher compared to acid process (13.75%). Reduction of lipid content and total volatile basic nitrogen (TVB-N) exhibited in both treatments indicated both process improved fish protein isolate recovered from red snapper by-product. In addition, the increasing of water holding capacity and oil binding capacity were observed. However, high peroxide value of fish protein isolate was showed in both treatment. This finding indicated that acid and alkali process can be used as a useful method to recover proteins from red snapper by-product. Alkali process gave a protein isolate with better overall quality compared to acid process.

  10. CHARACTERIZATION OF ENALAPRIL AND RANITIDINE CHLORINATION BY-PRODUCTS BY LIQUID CHROMATOGRAPHY/HIGH-RESOLUTION MASS SPECTROMETRY AND THEIR TOXICITY EVALUATION

    Directory of Open Access Journals (Sweden)

    Frederico Jehár Oliveira Quintão

    Full Text Available Due to its low cost, its capability for disinfection and oxidation, chlorination using gaseous chlorine or hypochlorite salts, has also been commonly applied in water treatment plants for oxidation and disinfection purposes. Little is known about the identity and toxicity of by-products resulting from the chlorination of pharmaceutical micropollutants, such as enalapril (ENA and ranitidine (RAN. ENA and RAN chlorination by-products were characterized in this study by high-performance liquid chromatography coupled to high-resolution mass spectrometry (HPLC/HRMS and their toxicity were assessed by MTT assay. Chlorination experiments with ENA and RAN solutions (10 mg L-1 indicate degradation efficiencies of 100% for both compounds after only 5 min of exposure to chlorine at concentration of 9.53 mg Cl2 L-1. On the other hand mineralization rates were lower than 3%, thereby indicating there was accumulation of degradation by-products in all experiments. Mass spectrometric analysis revealed, at all times of reaction after the addition of hypochlorite, the presence of 1-(2-((4-(chlorophenyl-1-ethoxy-1-oxobutan-2-ylaminopropanoylpyrrolidine-2-carboxylic acid (enalapril by-product and N-chloro-N-(2-(((chloro-5-((dimethylaminomethylfuran-2-ylmethylsulfinylethyl-N-methyl-2-nitroethene 1,1-diamine (ranitidine by-product. Despite the formation of oxidized chlorinated by-products in all chlorination assays, the treated solutions were nontoxic to HepG2 cells by the MTT assay. It has been observed that chlorination (10 mg L-1, 5 min of ENA and RAN solutions exhibited high degradation efficiencies of the target compounds and low mineralization rates. Based on the mass spectrometry data, the routes for ENA and RAN successive oxidation by chlorine has been proposed.

  11. Volatile composition and enantioselective analysis of chiral terpenoids of nine fruit and vegetable fibres resulting from juice industry by-products

    OpenAIRE

    Marsol i Vall, Alexis; Sgorbini, Barbara; Cagliero, Cecilia; Bicchi, Carlo; Eras i Joli, Jordi; Balcells Fluvià, Mercè

    2017-01-01

    Fruit and vegetable fibres resulting as by-products of the fruit juice industry have won popularity because they can be valorised as food ingredients. In this regard, bioactive compounds have already been studied but little attention has been paid to their remaining volatiles. Considering all the samples, 57 volatiles were identified. Composition greatly differed between citrus and noncitrus fibres. The former presented over 90% of terpenoids, with limonene being the most abundant and ranging...

  12. The effect of chlorine and combined chlorine/UV treatment on coliphages in drinking water disinfection.

    Science.gov (United States)

    Zyara, Alyaa M; Torvinen, Eila; Veijalainen, Anna-Maria; Heinonen-Tanski, Helvi

    2016-08-01

    Chlorine disinfection is a globally used method to ensure the safety of drinking water. However, it has not always been successful against viruses and, therefore, it is important to find new methods to disinfect water. Seventeen different coliphages were isolated from the treated municipal wastewater. These coliphages and MS2 were treated with different dosages of chlorine in drinking water, and a combined chlorine/ultraviolet irradiation treatment for the chlorine-resistant coliphages. Chlorine disinfection with 0.3-0.5 mg/L total chlorine (free Cl-dosage 0.12-0.21 mg/L) for 10 min achieved 2.5-5.7 Log10-reductions for 11 sensitive coliphages. The six most resistant coliphages showed no reduction with these chlorine concentrations. MS2 was intermediate in chlorine resistance, and thus it is not a good indicator for viruses in chlorine disinfection. In the combined treatment total chlorine of 0.05-0.25 mg/L (free Cl-dosage 0.02-0.08 mg/L) and ultraviolet irradiation (14-22 mWs/cm(2)) were more effective than chlorine alone, and 3-5 Log10-reductions were achieved for the chlorine-resistant strains. The chlorination efficiency could be increased by higher dosages and longer contact times, but this could increase the formation of disinfection by-products. Therefore, the combination treatment is a recommended disinfection method.

  13. Effectiveness of Disinfectants on Antimicrobial and Physical Properties of Dental Impression Materials.

    Science.gov (United States)

    Demajo, Jean Karl; Cassar, Valter; Farrugia, Cher; Millan-Sango, David; Sammut, Charles; Valdramidis, Vasilis; Camilleri, Josette

    2016-01-01

    The aim of this study was to assess the antimicrobial activity of chemical disinfectants on alginate and silicone impression materials. The effect of chemical disinfectants on the dimensional stability of the impression materials was also assessed. For the microbiologic assessment, impressions of the maxillary arch were taken from 14 participants, 7 using alginate and 7 using an addition silicone. The impressions were divided into three sections. Each section was subjected to spraying with MD 520 or Minuten or no disinfection (control), respectively. Antimicrobial action of the chemical disinfectants was assessed by measuring microbial counts in trypticase soy agar (TSA) media and expressing the results in colony-forming units/cm2. The surface area of the dental impressions was calculated by scanning a stone cast using computer-aided design/computer-assisted manufacture and analyzing the data using a custom computer program. The dimensional stability of the impression materials after immersion in disinfectants was assessed by measuring the linear displacement of horizontally restrained materials using a traveling microscope. The percent change in length over 3 hours was thus determined. Alginate exhibited a higher microbial count than silicone. MD 520 eliminated all microbes as opposed to Minuten. The bacterial growth after Minuten disinfection was almost twice as much for alginate than for addition silicone impressions. The chemical disinfectants affected the alginate dimensional stability. Minuten reduced the shrinkage sustained by alginate during the first hour of storage. Alginate harbors three times more microorganisms than silicone impression material. Chemical disinfection by glutaraldehyde-based disinfectant was effective in eliminating all microbial forms for both alginate and silicone without modifying the dimensional stability. Alcohol-based disinfectants, however, reduced the alginate shrinkage during the first 90 minutes of setting. The current studies

  14. Improving stethoscope disinfection at a children's hospital.

    Science.gov (United States)

    Zaghi, Justin; Zhou, Jing; Graham, Dionne A; Potter-Bynoe, Gail; Sandora, Thomas J

    2013-11-01

    Stethoscopes are contaminated with pathogenic bacteria and pose a risk for transmission of infections, but few clinicians disinfect their stethoscope after every use. We sought to improve stethoscope disinfection rates among pediatric healthcare providers by providing access to disinfection materials and visual reminders to disinfect stethoscopes. Prospective intervention study. Inpatient units and emergency department of a major pediatric hospital. Physicians and nurses with high anticipated stethoscope use. Baskets filled with alcohol prep pads and a sticker reminding providers to regularly disinfect stethoscopes were installed outside of patient rooms. Healthcare providers' stethoscope disinfection behaviors were directly observed before and after the intervention. Multivariable logistic regression models were created to identify independent predictors of stethoscope disinfection. Two hundred twenty-six observations were made in the preintervention period and 261 in the postintervention period (83% were of physicians). Stethoscope disinfection compliance increased significantly from a baseline of 34% to 59% postintervention (P stethoscope disinfection supplies and visible reminders outside of patient rooms significantly increased stethoscope disinfection rates among physicians and nurses at a children's hospital. This simple intervention could be replicated at other healthcare facilities. Future research should assess the impact on patient infections.

  15. The effect of various disinfectants on dental shade guides.

    Science.gov (United States)

    Huang, Peterson Y; Masri, Radi; Romberg, Elaine; Driscoll, Carl F

    2014-09-01

    Dental shade guides are used to evaluate tooth color before prosthodontic procedures and are subjected to disinfection after use. The effect of disinfection on shade guides has not been thoroughly investigated. The purpose of this study was to evaluate the effect of disinfectants on the color of shade tabs. Changes in the color (ΔE) of VITA Classical Shade Guide tabs were measured with a VITA Easyshade spectrophotometer in the CIELAB system and calculated after being subjected to Cavicide, Asepticare TB, Sporicidin, and distilled water (control) over a simulated period of 2 years. Statistical analysis was accomplished by a 2-way analysis of variance followed by the Tukey honestly significant difference (HSD) test (α=.05). A significant difference was noted in the degree of shade tab color change, depending on the type of disinfectant used (F=153.2, PCavicide (ΔE=1.198). The average total CIELAB color difference for 50% human perceptibility is approximately 1 unit (under standardized laboratory conditions). In the oral cavity, however, an average change of 3.7 ΔE units could still allow teeth to be perceived as having the same color. Therefore, although the results are statistically significant, they may not be clinically important. Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

  16. Fine Sprays for Disinfection within Healthcare

    Directory of Open Access Journals (Sweden)

    G Nasr

    2016-09-01

    Full Text Available Problems exist worldwide with Hospital Acquired Infections (HAI's. The Spray Research Group (SRG have been working with relevant industries in developing a product which can provide a delivery system for treatment chemicals for surfaces, including the design and testing of a novel Spill-Return Atomiser (SRA for this purpose. A comprehensive description of this atomiser has already been given. This paper reports on a new application of this atomiser and discusses the problem of spray coating for disinfection that has been considered very little in previous work. The related spray coating performance tests in developing the product are thus provided. The experimental work includes determining the required spray duration and the coverage area produced by different sprays, including the analysis of the effects of atomiser positions, configurations, and the required number of atomisers. Comparison is made with the efficacy of an ultrasonic gas atomiser that is currently used for this purpose. The investigation has found that the utilisation of fine sprays (10μm>D32>25μm at high liquid pressure (<12MPa and low flow rates (<0.3 l/min is suitable for surface disinfection in healthcare applications (i.e. MRSA, VRSA etc.

  17. Evacuation of performance and significant chemical constituents and by products in drinking water treatment

    International Nuclear Information System (INIS)

    Jamrah, I. A.

    1999-01-01

    Drinking water treatment is a task that comprises of several processes that eventually lead to the addition of chemicals to achieve the objectives of treatment. This study was conducted to assess treatment performance, explain the presence of significant chemical species in water, and investigate the interactions and chemical by-products that are formed during the course of treatment. Grab water samples were collected on a regular basis from the influent and effluent of Zai water treatment plant. Chemical analysis were conducted to determine the concentrations of various chemical species of interest. Turbidity, temperature, and pH of the samples were also measured. The study concluded that Zai Water Treatment Plant produces potable drinking water in accordance with Jordanian Standards. The use of treatment chemical resulted in an increase in the concentrations of certain materials, such as manganese, aluminum, and sulfate. The turbidity of the raw water and the TOC of the samples were positively correlated, and the treatment results in approximately 20% TOC reduction, which demonstrates that the measures used for the control of TOC (carbon adsorption and permanganate pre-oxidation), are not very effective. The study also showed that the TOC content of our raw water samples and the concentration of tribalomethanes resulting after disinfection were positively correlated, and that bromoform was the dominant component. Also chloroform was the minor component of tribalomethanes formed during treatment. Positive correlation between the total concentration of tribalomethanes in water and the chlorine dose used for disinfection was also observed, and the total concentration of tribalomethanes increased with temperature. The formation of tribalomethanes was enhanced as the pH of water increased and as the concentration of bromide ion in raw water became significant. (author). 25 refs., 14 figs.1 table

  18. Thermodynamic properties of an emerging chemical disinfectant, peracetic acid.

    Science.gov (United States)

    Zhang, Chiqian; Brown, Pamela J B; Hu, Zhiqiang

    2018-04-15

    Peracetic acid (PAA or CH 3 COOOH) is an emerging disinfectant with a low potential to form carcinogenic disinfection by-products (DBPs). Basic thermodynamic properties of PAA are, however, absent or inconsistently reported in the literature. This review aimed to summarize important thermodynamic properties of PAA, including standard Gibbs energy of formation and oxidation-reduction (redox) potential. The standard Gibbs energies of formation of CH 3 COOOH (aq) , CH 3 COOOH (g) , CH 3 COOOH (l) , and CH 3 COOO (aq) - are -299.41kJ·mol -1 , -283.02kJ·mol -1 , -276.10kJ·mol -1 , and -252.60kJ·mol -1 , respectively. The standard redox potentials of PAA are 1.748V and 1.005V vs. standard hydrogen electrode (SHE) at pH 0 and pH 14, respectively. Under biochemical standard state conditions (pH 7, 25°C, 101,325Pa), PAA has a redox potential of 1.385V vs. SHE, higher than many disinfectants. Finally, the environmental implications of the thermodynamic properties of PAA were systematically discussed. Those properties can be used to predict the physicochemical and biological behavior of aquatic systems exposed to PAA. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Wastewater disinfection by combination of ultrasound and ultraviolet irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Naddeo, V., E-mail: vnaddeo@unisa.it [Department of Civil Engineering, University of Salerno, Via Ponte don Melillo, 1, 84084 Fisciano (Italy); Landi, M.; Belgiorno, V. [Department of Civil Engineering, University of Salerno, Via Ponte don Melillo, 1, 84084 Fisciano (Italy); Napoli, R.M.A. [Department of Environmental Science, University of Napoli Parthenope, Via Amm. F. Acton, 38, 80133 Napoli (Italy)

    2009-09-15

    Reclamation and reuse of wastewater is one of the most effective ways to alleviate water resource scarcity. In many countries very stringent limit for chlorination by-products such as trihalomethanes has been set for wastewater reuse. Accordingly, the use of alternative oxidation/disinfection systems should be evaluated as possible alternative to chlorine. Recently ultrasound (US) was found to be effective as pre-treatment for wastewater disinfection by UV irradiation. The aim of this work is to investigate the wastewater advanced treatment by simultaneous combination of UV and US in terms of bacteria inactivation (Total coliform and Escherichia coli) at pilot-scale. The pilot plant was composed of two reactors: US-UV reactor and UV reactor. The influence of different reaction times, respective US and UV dose and synergistic effect was tested and discussed for two different kinds of municipal wastewater. An important enhancement of UV disinfection ability has been observed in presence of US, especially with wastewater characterized by low transmittance. In particular the inactivation was greater for T. coliform than for E. coli. Furthermore, the results obtained showed also that the fouling formation on the lamps was slower in US-UV reactor than in UV reactor both with and without solar radiation.

  20. Wastewater disinfection by combination of ultrasound and ultraviolet irradiation

    International Nuclear Information System (INIS)

    Naddeo, V.; Landi, M.; Belgiorno, V.; Napoli, R.M.A.

    2009-01-01

    Reclamation and reuse of wastewater is one of the most effective ways to alleviate water resource scarcity. In many countries very stringent limit for chlorination by-products such as trihalomethanes has been set for wastewater reuse. Accordingly, the use of alternative oxidation/disinfection systems should be evaluated as possible alternative to chlorine. Recently ultrasound (US) was found to be effective as pre-treatment for wastewater disinfection by UV irradiation. The aim of this work is to investigate the wastewater advanced treatment by simultaneous combination of UV and US in terms of bacteria inactivation (Total coliform and Escherichia coli) at pilot-scale. The pilot plant was composed of two reactors: US-UV reactor and UV reactor. The influence of different reaction times, respective US and UV dose and synergistic effect was tested and discussed for two different kinds of municipal wastewater. An important enhancement of UV disinfection ability has been observed in presence of US, especially with wastewater characterized by low transmittance. In particular the inactivation was greater for T. coliform than for E. coli. Furthermore, the results obtained showed also that the fouling formation on the lamps was slower in US-UV reactor than in UV reactor both with and without solar radiation.

  1. Influence of sublethal concentrations of common disinfectants on expression of virulence genes in Listeria monocytogenes

    DEFF Research Database (Denmark)

    Kastbjerg, Vicky Gaedt; Larsen, M. H.; Gram, Lone

    2010-01-01

    Listeria monocytogenes is a food-borne human pathogen that causes listeriosis, a relatively rare infection with a high fatality rate. The regulation of virulence gene expression is influenced by several environmental factors, and the aim of the present study was to determine how disinfectants use......, such as antibiotic resistance....... by Northern blot analysis. Eleven disinfectants representing four different groups of active components were evaluated in this study. Disinfectants with the same active ingredients had a similar effect on gene expression. Peroxy and chlorine compounds reduced the expression of the virulence genes...

  2. Disinfection of drain water of tomato by means of UV radiation and slow sand filtration in real greenhouse circumstances.

    Science.gov (United States)

    De Rocker, E; Goen, K; Van Poucke, K

    2006-01-01

    The efficiency of the disinfection of drain water was tested at 11 greenhouses with tomato cultivation on rockwool substrate in Flanders (Belgium) by means of mycological analysis. In addition the presence of phytopathogenic fungi in the drain water was analysed at 2 supplementary greenhouses with recirculation without disinfection.

  3. Disinfection by-product formation of UV treated swimming pool water

    DEFF Research Database (Denmark)

    Spiliotopoulou, Aikaterini; Hansen, Kamilla Marie Speht; Andersen, Henrik Rasmus

    2015-01-01

    Water samples from 3 indoor swimming pool facilities were tested to evaluate UV-induced effects on swimming pool water chemistry. Concentration change of several DBPs was investigated in experiments including medium pressure UV treatment with and without chlorine and post-UV chlorination. Post-UV...

  4. Prediction of N-nitrosodimethylamine (NDMA) formation as a disinfection by-product.

    Science.gov (United States)

    Kim, Jongo; Clevenger, Thomas E

    2007-06-25

    This study investigated the possibility of a statistical model application for the prediction of N-nitrosodimethylamine (NDMA) formation. The NDMA formation was studied as a function of monochloramine concentration (0.001-5mM) at fixed dimethylamine (DMA) concentrations of 0.01mM or 0.05mM. Excellent linear correlations were observed between the molar ratio of monochloramine to DMA and the NDMA formation on a log scale at pH 7 and 8. When a developed prediction equation was applied to a previously reported study, a good result was obtained. The statistical model appears to predict adequately NDMA concentrations if other NDMA precursors are excluded. Using the predictive tool, a simple and approximate calculation of NDMA formation can be obtained in drinking water systems.

  5. By-products by design

    International Nuclear Information System (INIS)

    Collins, Richard

    2011-01-01

    Full text: Some mining by-products that are currently stockpiled or disposed of could be put to use preventing nutrients from entering river systems, helping reduce the potential for algal blooms. A joint project between CSIRO and the Western Australia (WA) Department of Water investigated a range of spent materials from mining and industry to determine their ability to filter nutrients from natural waters or to treat wastewater. “The largely unexploited by-product materials we generate in Western Australia could be developed as 'designer' contaminant adsorbents,” said CSIRO project leader Dr Grant Douglas. The use of abundant, low-cost wastes generated from mineral processing, in particular, offers a potentially cost- effective and environmentally-friendly strategy for removing nutrients. “The productive use of the by-products also has the potential to reduce the environmental footprint of mining and mineral processing industries by lowering by-product stockpiles,” he said. But the key benefits are in water; not only improving the health of surface waters but, by facilitating reuse, also easing the competition for water resources in an increasingly climate constrained part of the country. Re-use of industrial by-products in WA is currently considered on a case-by-case basis rather than regulated according to established standards. The project aimed to inject some rigour by characterising for the first time the nutrient, trace element uptake and acid neutralising capacity of a range of low-cost by-products (see Fact File). It also underpinned the development of a draft protocol for screening similar by-products in the future. The comprehensive characterisation included identification and procurement, and basic characterisation of by-products included major and trace element geochemistry, mineralogy, radioactivity, geochemical modelling and leachate chemistry and toxicity. These inherent properties and suitability of by-products for potential environmental

  6. Combined UV treatment and ozonation for the removal of by-product precursors in swimming pool water

    DEFF Research Database (Denmark)

    Cheema, Waqas Akram; Kaarsholm, Kamilla Marie Speht; Andersen, Henrik Rasmus

    2017-01-01

    Both UV treatment and ozonation are used to reduce different types of disinfection by-products (DBPs) in swimming pools. UV treatment is the most common approach, as it is particularly efficient at removing combined chlorine. However, the UV treatment of pool water increases chlorine reactivity...

  7. In situ disinfection of sewage contaminated shallow groundwater: a feasibility study.

    Science.gov (United States)

    Bailey, Morgan M; Cooper, William J; Grant, Stanley B

    2011-11-01

    Sewage-contaminated shallow groundwater is a potential cause of beach closures and water quality impairment in marine coastal communities. In this study we set out to evaluate the feasibility of several strategies for disinfecting sewage-contaminated shallow groundwater before it reaches the coastline. The disinfection rates of Escherichia coli (EC) and enterococci bacteria (ENT) were measured in mixtures of raw sewage and brackish shallow groundwater collected from a coastal community in southern California. Different disinfection strategies were explored, ranging from benign (aeration alone, and aeration with addition of brine) to aggressive (chemical disinfectants peracetic acid (PAA) or peroxymonosulfate (Oxone)). Aeration alone and aeration with brine did not significantly reduce the concentration of EC and ENT after 6 h of exposure, while 4-5 mg L(-1) of PAA or Oxone achieved >3 log reduction after 15 min of exposure. Oxone disinfection was more rapid at higher salinities, most likely due to the formation of secondary oxidants (e.g., bromine and chlorine) that make this disinfectant inappropriate for marine applications. Using a Lagrangian modeling framework, we identify several factors that could influence the performance of in-situ disinfection with PAA, including the potential for bacterial regrowth, and the non-linear dependence of disinfection rate upon the residence time of water in the shallow groundwater. The data and analysis presented in this paper provide a framework for evaluating the feasibility of in-situ disinfection of shallow groundwater, and elucidate several topics that warrant further investigation. Copyright © 2011 Elsevier Ltd. All rights reserved.

  8. Disinfecting the iPad: evaluating effective methods.

    Science.gov (United States)

    Howell, V; Thoppil, A; Mariyaselvam, M; Jones, R; Young, H; Sharma, S; Blunt, M; Young, P

    2014-06-01

    Tablet computers are increasingly used in healthcare, but they may carry nosocomial pathogens. There are few data available on how to clean an iPad effectively for use in the clinical setting. We aimed to identify the most effective method of decontaminating the Apple iPad, without causing damage, and establish the duration of any residual effect. Following contamination with a microbial broth (meticillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococcus (VRE) and Clostridium difficile), we examined efficacy of iPad disinfection in the laboratory using six different disinfectant wipes: Sani-Cloth CHG 2% (chlorhexidine 2%/alcohol 70%), Clorox, Tristel, Trigene, soap and water, and plain cloth. Following cleaning, iPads were recontaminated to examine residual activity. After 480 Sani-Cloth CHG 2% disinfecting episodes, functional and visual analysis of iPads was performed by blinded subjects. With the exception of Clostridium difficile, Sani-Cloth CHG 2% and Clorox wipes were most effective against MRSA and VRE, and they were significantly better than the Apple-recommended plain cloth (P ≤ 0.001). A substantial residual antimicrobial effect was seen for >6h after wiping the iPad with Sani-Cloth CHG 2% despite repeated recontamination and without further disinfection. The functionality or visual appearance of the iPad was not damaged by repeated use of Sani-Cloth CHG 2% wipes. Sani-Cloth CHG 2% wipes effectively disinfect the iPad against MRSA and VRE, with a residual antibacterial effect and without causing damage. Copyright © 2014 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

  9. Dimensional Stability of Color-Changing Irreversible Hydrocolloids after Disinfection

    Directory of Open Access Journals (Sweden)

    Khaledi AAR

    2015-03-01

    Full Text Available Statement of Problem: Disinfection of dental impressions is a weak point in the dental hygiene chain. In addition, dental office personnel and dental technicians are endangered by cross-contamination. Objectives: This study aimed to investigate the dimensional stability of two color-changing irreversible hydrocolloid materials (IH after disinfection with glutaraldehyde. Materials and Methods: In this in vitro study, impressions were made of a master maxillary arch containing three reference inserts on the occlucal surface of the left and right maxillary second molars and in the incisal surface of the maxillary central incisors. Two types of color-changing irreversible hydrocolloid (tetrachrom, cavex were used. Glutaraldehyde 2% was used in two methods of spraying and immersion to disinfect the impressions. The control group was not disinfected. Casts were made of type IV gypsum. The linear dimensional change of the stone casts was measured with a profile projector. For statistical analysis, Kruskall-Wallis and Mann-Witney tests were used (α=0.05. Results: By immersion method, the casts fabricated from tetrachrom were 0.36% larger in the anteroposterior (AP and 0.05% smaller in cross arch (CA dimensions; however, the casts prepared after spraying of tetrachrom were 0.44% larger in the AP and 0.10% smaller in CA dimensions. The casts made from Cavex were 0.05% smaller in the AP and 0.02% smaller in CA dimensions after spraying and 0.01% smaller in the AP and 0.003% smaller in CA dimensions after immersion. Generally there were not significant differences in AP and CA dimensions of the experimental groups compared to the control (p > 0.05. Conclusions: Disinfection of the tested color-changing irreversible hydrocolloids by glutaraldahyde 2% did not compromise the accuracy of the obtained casts.

  10. An environmental disinfection odyssey: evaluation of sequential interventions to improve disinfection of Clostridium difficile isolation rooms.

    Science.gov (United States)

    Sitzlar, Brett; Deshpande, Abhishek; Fertelli, Dennis; Kundrapu, Sirisha; Sethi, Ajay K; Donskey, Curtis J

    2013-05-01

    OBJECTIVE. Effective disinfection of hospital rooms after discharge of patients with Clostridium difficile infection (CDI) is necessary to prevent transmission. We evaluated the impact of sequential cleaning and disinfection interventions by culturing high-touch surfaces in CDI rooms after cleaning. DESIGN. Prospective intervention. SETTING. A Veterans Affairs hospital. INTERVENTIONS. During a 21-month period, 3 sequential tiered interventions were implemented: (1) fluorescent markers to provide monitoring and feedback on thoroughness of cleaning facility-wide, (2) addition of an automated ultraviolet radiation device for adjunctive disinfection of CDI rooms, and (3) enhanced standard disinfection of CDI rooms, including a dedicated daily disinfection team and implementation of a process requiring supervisory assessment and clearance of terminally cleaned CDI rooms. To determine the impact of the interventions, cultures were obtained from CDI rooms after cleaning and disinfection. RESULTS. The fluorescent marker intervention improved the thoroughness of cleaning of high-touch surfaces (from 47% to 81% marker removal; P disinfection, whereas during interventions periods 1, 2, and 3 the percentages of CDI rooms with positive cultures after disinfection were reduced to 57%, 35%, and 7%, respectively. CONCLUSIONS. An intervention that included formation of a dedicated daily disinfection team and implementation of a standardized process for clearing CDI rooms achieved consistent CDI room disinfection. Culturing of CDI rooms provides a valuable tool to drive improvements in environmental disinfection.

  11. Toxicogenomic response of Mycobacterium bovis BCG to peracetic acid and a comparative analysis of the M. bovis BCG response to three oxidative disinfectants.

    Science.gov (United States)

    Nde, Chantal W; Toghrol, Freshteh; Jang, Hyeung-Jin; Bentley, William E

    2011-04-01

    Tuberculosis is a leading cause of death worldwide and infects thousands of Americans annually. Mycobacterium bovis causes tuberculosis in humans and several animal species. Peracetic acid is an approved tuberculocide in hospital and domestic environments. This study presents for the first time the transcriptomic changes in M. bovis BCG after treatment with 0.1 mM peracetic acid for 10 and 20 min. This study also presents for the first time a comparison among the transcriptomic responses of M. bovis BCG to three oxidative disinfectants: peracetic acid, sodium hypochlorite, and hydrogen peroxide after 10 min of treatment. Results indicate that arginine biosynthesis, virulence, and oxidative stress response genes were upregulated after both peracetic acid treatment times. Three DNA repair genes were downregulated after 10 and 20 min and cell wall component genes were upregulated after 20 min. The devR-devS signal transduction system was upregulated after 10 min, suggesting a role in the protection against peracetic acid treatment. Results also suggest that peracetic acid and sodium hypochlorite both induce the expression of the ctpF gene which is upregulated in hypoxic environments. Further, this study reveals that in M. bovis BCG, hydrogen peroxide and peracetic acid both induce the expression of katG involved in oxidative stress response and the mbtD and mbtI genes involved in iron regulation/virulence.

  12. In silico identification of a therapeutic target for photo-activated disinfection with indocyanine green: Modeling and virtual screening analysis of Arg-gingipain from Porphyromonas gingivalis.

    Science.gov (United States)

    Pourhajibagher, Maryam; Bahador, Abbas

    2017-06-01

    Porphyromonas gingivalis is a momentous bacterial etiological agent associated with periodontitis, peri-implantitis as well as endodontic infections. The potential advantage of Photo-activated disinfection (PAD) as a promising novel approach is the choice of a suitable target site, specific photosensitizer, and wavelength of light for delivery of the light from source to target. Since Arg-gingipain is a cysteine proteinase that is involved in the virulence of P. gingivalis, it was evaluated as a target site for PAD with indocyanine green (ICG) as a photosensitizer. In this study, we used a range of in silico strategies, bioinformatics tools, biological databases, and computer simulation molecular modeling to evaluate the capacity of Arg-gingipain. The predicted structure of Arg-gingipain indicated that it is located outside the cell and has nine domains and 17 ligands, including two calcium ions and three sodium ions with positive charges which can be a site of interaction for anionic ICG. Based on the results of this study, anionic ICG desires to bind and interact with residues of Arg-gingipain during PAD as a main site to enhance the yield of treatment of endo-periodontal lesions. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Anaerobic effluent disinfection using ozone: Byproducts formation

    NARCIS (Netherlands)

    Silva, G.H.R.; Daniel, L.A.; Bruning, H.; Rulkens, W.H.

    2010-01-01

    This research was aimed at studying oxidation processes, coliform inactivation effectiveness and disinfection byproducts (DBPs) associated with the disinfection of anaerobic sanitary wastewater effluent with ozone applied at doses of 5.0, 8.0 and 10.0mg O(3)L(-1) for contact times of 5, 10 and 15

  14. Ultraviolet (UV) Disinfection for Drinking Water Systems

    Science.gov (United States)

    UV disinfection is an effective process for inactivating many microbial pathogens in water with potential to serve as stand-alone treatment or in combination with other disinfectants. USEPA provided guidance on the validation of UV reactors nearly a decade ago. Since then, lesson...

  15. Silver disinfection in water distribution systems

    Science.gov (United States)

    Silvestry Rodriguez, Nadia

    Silver was evaluated as disinfectant to maintain water quality in water distribution system. It was used to inhibit growth of two opportunistic bacteria in planktonik form and in biofilm formation in Robbins devices with stainless steel and PVC surfaces. The results of this work show that silver is a potential secondary disinfectant to be used in water distribution systems.

  16. Chemical disinfection of combined sewer overflows

    DEFF Research Database (Denmark)

    Chhetri, Ravi Kumar

    of the residual disinfectants PFA, PAA and chlorine dioxide (ClO2), and their degradation products hydrogen peroxide and chlorite, in relation to organisms in the aquatic ecosystem was studied. With the help of ecotoxicity data, a preliminary environmental risk assessment of PFA, PAA and ClO2 for CSO disinfection...

  17. Adaptive Mechanisms Underlying Microbial Resistance to Disinfectants

    Science.gov (United States)

    2016-02-01

    11775]). E.coli is a gram-negative, facultative anaerobic, and rod-shaped bacteria commonly found in warm-blooded animals . 2.1.2 Disinfectants...Nisbet, D.J. Disinfectant and Antibiotic Susceptibility Profiles of Escherichia coli O157:H7 Strains from Cattle Carcasses , Feces, and Hides and

  18. Comparison of organic peracids in wastewater treatment: Disinfection, oxidation and corrosion.

    Science.gov (United States)

    Luukkonen, Tero; Heyninck, Tom; Rämö, Jaakko; Lassi, Ulla

    2015-11-15

    The use of organic peracids in wastewater treatment is attracting increasing interest. The common beneficial features of peracids are effective anti-microbial properties, lack of harmful disinfection by-products and high oxidation power. In this study performic (PFA), peracetic (PAA) and perpropionic acids (PPA) were synthesized and compared in laboratory batch experiments for the inactivation of Escherichia coli and enterococci in tertiary wastewater, oxidation of bisphenol-A and for corrosive properties. Disinfection tests revealed PFA to be a more potent disinfectant than PAA or PPA. 1.5 mg L(-1) dose and 2 min of contact time already resulted in 3.0 log E. coli and 1.2 log enterococci reduction. Operational costs of disinfection were estimated to be 0.0114, 0.0261 and 0.0207 €/m(3) for PFA, PAA and PPA, respectively. Disinfection followed the first order kinetics (Hom model or S-model) with all studied peracids. However, in the bisphenol-A oxidation experiments involving Fenton-like conditions (pH = 3.5, Fe(2+) or Cu(2+) = 0.4 mM) peracids brought no additional improvement to traditionally used and lower cost hydrogen peroxide. Corrosion measurements showed peracids to cause only a negligible corrosion rate (<6 μm year(-1)) on stainless steel 316L while corrosion rates on the carbon steel sample were significantly higher (<500 μm year(-1)). Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Wastewater disinfection by peracetic acid: assessment of models for tracking residual measurements and inactivation.

    Science.gov (United States)

    Santoro, Domenico; Gehr, Ronald; Bartrand, Timothy A; Liberti, Lorenzo; Notarnicola, Michele; Dell'Erba, Adele; Falsanisi, Dario; Haas, Charles N

    2007-07-01

    With its potential for low (if any) disinfection byproduct formation and easy retrofit for chlorine contactors, peracetic acid (PAA) or use of PAA in combination with other disinfectant technologies may be an attractive alternative to chlorine-based disinfection. Examples of systems that might benefit from use of PAA are water reuse schemes or plants discharging to sensitive receiving water bodies. Though PAA is in use in numerous wastewater treatment plants in Europe, its chemical kinetics, microbial inactivation rates, and mode of action against microorganisms are not thoroughly understood. This paper presents results from experimental studies of PAA demand, PAA decay, and microbial inactivation, with a complementary modeling analysis. Model results are used to evaluate techniques for measurement of PAA concentration and to develop hypotheses regarding the mode of action of PAA in bacterial inactivation. Kinetic and microbial inactivation rate data were collected for typical wastewaters and may be useful for engineers in evaluating whether to convert from chlorine to PAA disinfection.

  20. [Survey of synthetic disinfectants in grapefruit seed extract and its compounded products].

    Science.gov (United States)

    Sugimoto, Naoki; Tada, Atsuko; Kuroyanagi, Masanori; Yoneda, Yuko; Yun, Young Sook; Kunugi, Akira; Sato, Kyoko; Yamazaki, Takeshi; Tanamoto, Ken-Ichi

    2008-02-01

    Grapefruit seed extract (GSE), derived from the seeds of grapefruit (Citrus paradisi MCAF.), is listed as a natural food additive in Japan. Products containing GSE are used as disinfectants made from only natural sources, especially after Japanese researchers found that GSE prevents the growth of norovirus. On the other hand, recent overseas studies indicated that synthetic disinfectants, such as benzalkonium and benzethonium chlorides, were present in some commercial GSE products. To confirm the quality of commercial GSE products available in Japanese markets, we carried out comprehensive research to identify the major constituents of commercial GSE products which are used as food additives (13 products from 6 manufacturers), dietary supplements (5 products from 4 manufacturers), cosmetic materials (16 products from 10 manufacturers) and disinfectant or deodorant sprays (7 products from 7 manufacturers). By means of NMR and LC/MS analysis, synthetic disinfectants such as benzethonium or benzalkonium salts were detected in most of the commercial GSE products.

  1. Cleaning and Disinfection of Bacillus cereus Biofilm.

    Science.gov (United States)

    Deal, Amanda; Klein, Dan; Lopolito, Paul; Schwarz, John Spencer

    2016-01-01

    Methodology has been evolving for the testing of disinfectants against bacterial single-species biofilms, as the difficulty of biofilm remediation continues to gain much-needed attention. Bacterial single-species biofilm contamination presents a real risk to good manufacturing practice-regulated industries. However, mixed-species biofilms and biofilms containing bacterial spores remain an even greater challenge for cleaning and disinfection. Among spore-forming microorganisms frequently encountered in pharmaceutical manufacturing areas, the spores of Bacillus cereus are often determined to be the hardest to disinfect and eradicate. One of the reasons for the low degree of susceptibility to disinfection is the ability of these spores to be encapsulated within an exopolysachharide biofilm matrix. In this series of experiments, we evaluated the disinfectant susceptibility of B. cereus biofilms relative to disassociated B. cereus spores and biofilm from a non-spore-forming species. Further, we assessed the impact that pre-cleaning has on increasing that susceptibility. Methodology has been evolving for the testing of disinfectants against bacterial single-species biofilms, as the difficulty of biofilm remediation continues to gain much-needed attention. Bacterial single-species biofilm contamination presents a real risk to good manufacturing practice-regulated industries. However, mixed-species biofilms and biofilms containing bacterial spores remain an even greater challenge for cleaning and disinfection. Among spore-forming microorganisms frequently encountered in pharmaceutical manufacturing areas, the spores of Bacillus cereus are often determined to be the hardest to disinfect and eradicate. One of the reasons for the low degree of susceptibility to disinfection is the ability of these spores to be encapsulated within an exopolysachharide biofilm matrix. In this series of experiments, we evaluated the disinfectant susceptibility of B. cereus biofilms relative to

  2. Characterization of micro-organisms isolated from dairy industry after cleaning and fogging disinfection with alkyl amine and peracetic acid.

    Science.gov (United States)

    Bore, E; Langsrud, S

    2005-01-01

    To characterize micro-organisms isolated from Norwegian dairy production plants after cleaning and fogging disinfection with alkyl amine/peracetic acid and to indicate reasons for survival. Microbial samples were collected from five dairy plants after cleaning and fogging disinfection. Isolates from two of these production plants, which used fogging with alkylamino acetate (plant A), and peracetic acid (plant B), were chosen for further characterization. The sequence of the 16S ribosomal DNA, fatty acid analysis and biochemical characteristics were used to identify isolates. Three isolates identified as Rhodococcus erythropolis, Methylobacterium rhodesianum and Rhodotorula mucilaginosa were isolated from plant A and one Sphingomonas sp. and two M. extorquens from plant B. Different patterns of resistance to seven disinfectants in a bactericidal suspension test and variable degree of attachment to stainless steel were found. The strains with higher disinfectant resistance showed lower degree of attachment than susceptible strains. The study identifies and characterizes micro-organisms present after cleaning and fogging disinfection. Both surface attachment and resistance were shown as possible reasons for the presence of the isolates after cleaning and disinfection. These results contribute to the awareness of disinfectant resistance as well as attachment as mechanisms of survival in dairy industry. It also strengthens the argument of frequent alternation of disinfectants in the food processing industry to avoid the establishment of resistant house strains.

  3. 9 CFR 166.14 - Cleaning and disinfecting.

    Science.gov (United States)

    2010-01-01

    ... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Cleaning and disinfecting. 166.14... AGRICULTURE SWINE HEALTH PROTECTION SWINE HEALTH PROTECTION General Provisions § 166.14 Cleaning and disinfecting. (a) Disinfectants to be used. Disinfection required under the regulations in this Part shall be...

  4. 9 CFR 83.7 - Shipping containers; cleaning and disinfection.

    Science.gov (United States)

    2010-01-01

    ... HEMORRHAGIC SEPTICEMIA § 83.7 Shipping containers; cleaning and disinfection. (a) All live fish that are to be... been cleaned and disinfected. (1) Cleaning and disinfection of shipping containers must be monitored by... who issues the ICI. (2) Cleaning and disinfection must be sufficient to neutralize any VHS virus to...

  5. Surface Disinfections: Present and Future

    Directory of Open Access Journals (Sweden)

    Matteo Saccucci

    2018-01-01

    Full Text Available The propagation of antibiotic resistance increases the chances of major infections for patients during hospitalization and the spread of health related diseases. Therefore finding new and effective solutions to prevent the proliferation of pathogenic microorganisms is critical, in order to protect hospital environment, such as the surfaces of biomedical devices. Modern nanotechnology has proven to be an effective countermeasure to tackle the threat of infections. On this note, recent scientific breakthroughs have demonstrated that antimicrobial nanomaterials are effective in preventing pathogens from developing resistance. Despite the ability to destroy a great deal of bacteria and control the outbreak of infections, nanomaterials present many other advantages. Moreover, it is unlikely for nanomaterials to develop resistance due to their multiple and simultaneous bactericidal mechanisms. In recent years, science has explored more complex antimicrobial coatings and nanomaterials based on graphene have shown great potential in antibacterial treatment. The purpose of this article is to deepen the discussion on the threat of infections related to surface disinfection and to assess the state of the art and potential solutions, with specific focus on disinfection procedures using nanomaterials.

  6. Sonochemical disinfection of municipal wastewater

    International Nuclear Information System (INIS)

    Antoniadis, Apostolos; Poulios, Ioannis; Nikolakaki, Eleni; Mantzavinos, Dionissios

    2007-01-01

    The application of high intensity, low frequency ultrasound for the disinfection of simulated and septic tank wastewaters is evaluated in this work. Laboratory scale experiments were conducted at 24 and 80 kHz ultrasound frequency with horn-type sonicators capable of operating in continuous and pulsed irradiation modes at nominal ultrasound intensities up to 450 W. For the experiments with simulated wastewaters, Escherichia coli were used as biological indicator of disinfection efficiency, while for the experiments with septic tank wastewaters, the total microbiological load was used. Complete elimination of E. coli could be achieved within 20-30 min of irradiation at 24 kHz and 450 W with the efficiency decreasing with decreasing intensity and frequency. Moreover, continuous irradiation was more effective than intermittent treatment based on a common energy input. Irradiation of the septic tank effluent prior to biological treatment at 24 kHz and 450 W for 30 min resulted in a three-log total microbiological load reduction, and this was nearly equal to the reduction that could be achieved during biological treatment. Bacterial cell elimination upon irradiation was irreversible as no reappearance of the microorganisms occurred after 24 h

  7. Decision-making impairments in Parkinson's disease as a by-product of defective cost-benefit analysis and feedback processing.

    Science.gov (United States)

    Ryterska, Agata; Jahanshahi, Marjan; Osman, Magda

    2014-01-01

    Studies examining decision-making in people with Parkinson's disease (PD) show impaired performance on a variety of tasks. However, there are also demonstrations that patients with PD can make optimal decisions just like healthy age-matched controls. We propose that the reason for these mixed findings is that PD does not produce a generalized impairment of decision-making, but rather affects sub-components of this process. In this review we evaluate this hypothesis by considering the empirical evidence examining decision-making in PD. We suggest that of the various stages of the decision-making process, the most affected in PD are (1) the cost-benefit analysis stage and (2) the outcome evaluation stage. We consider the implications of this proposal for research in this area.

  8. Modifications of Atlantic salmon by-product oil for obtaining different ω-3 polyunsaturated fatty acids concentrates: An approach to comparative analysis

    Directory of Open Access Journals (Sweden)

    Monjurul Haq

    2018-04-01

    Full Text Available Omega-3 polyunsaturated fatty acids (ω-3 PUFAs rich 2-monoacylglycerols (2-MAG, omega-3 polyunsaturated free fatty acids (ω-3 PUFFAs concentrate, and PUFA enriched acylglycerols were prepared from salmon frame bone oil (SFBO by enzymatic alcoholysis, urea complexation, and enzymatic esterification, respectively. The yields of 2-MAG, ω-3 PUFFAs concentrate, and PUFA enriched acylglycerols were 40.25, 16.52, and 15.65%, respectively. ω-3 PUFFAs concentrate and PUFA enriched acylglycerols showed darker red color than SFBO and 2-MAG due to aggregation of astaxanthin pigment in ω-3 PUFFAs concentrate during urea complexation. The viscosity and specific gravity of SFBO and PUFA enriched acylglycerols showed similar values whereas 2-MAG and ω-3 PUFFAs showed significantly (p < 0.05 lower values. Stability parameters like acid value, peroxide value, free fatty acid value, and p-anisidine value of SFBO and ω-3 PUFAs concentrates were within acceptable limits except extreme high acid value and free fatty acid value of ω-3 PUFFAs concentrate. Thermogravimetric analysis showed similar and higher thermal stability of SFBO and PUFA enriched acylglycerols than 2-MAG and ω-3 PUFFAs concentrate. The ω-3 PUFAs content in 2-MAG, ω-3 PUFFAs concentrate, and PUFA enriched acylglycerols was increased to 20.81, 52.96, and 51.74% respectively from 13.54% in SFBO. ω-3 PUFFAs concentrate and PUFA enriched acylglycerols showed higher DPPH and ABTS radical scavenging activity than SFBO and 2-MAG. The results obtained from this study suggest the production of PUFA enriched acylglycerols rich in ω-3 PUFAs supplements from fish oil for human and pet animals. Keywords: Comparative analysis, ω-3 PUFFAs concentrate, Salmon frame bone oil, PUFA enriched acylglycerols, 2-MAG

  9. Ultraviolet disinfection of treated municipal wastewaters

    Energy Technology Data Exchange (ETDEWEB)

    Vander Laan, H; Cairns, B

    1993-12-31

    A wastewater disinfection system developed by a Canadian company, Trojan Technologies Inc., was discussed. Disinfection for pathogen reduction prior to discharge of treated municipal wastewater back into rivers and lakes has been either ignored or treated by the use of chemicals. In 1979 the first pilot ultraviolet (UV) wastewater disinfection system was established. Since then, over 500 municipal UV installations have been commissioned. The largest installation can process 212 million gallons of water per day. The advantages of UV as a disinfectant are: (1) It is more effective than chlorine. (2) There are no mutagenic/carcinogenic byproducts formed with UV. (3) No toxic chemical residuals are discharged. (4) UV is safe to both the operators and the public. (5) It is cost effective. Europe has not been as active in wastewater disinfection as has North America. One result of the absence of wastewater disinfection in Europe is that the Rhine River, for example, carries 50 million salmonella per second. Disinfection of wastewater effluents is, of course, indispensable in protecting our drinking water supply. 2 figs.

  10. A dynamic metabolic flux analysis of ABE (acetone-butanol-ethanol) fermentation by Clostridium acetobutylicum ATCC 824, with riboflavin as a by-product.

    Science.gov (United States)

    Zhao, Xinhe; Kasbi, Mayssa; Chen, Jingkui; Peres, Sabine; Jolicoeur, Mario

    2017-12-01

    The present study reveals that supplementing sodium acetate (NaAc) strongly stimulates riboflavin production in acetone-butanol-ethanol (ABE) fermentation by Clostridium acetobutylicum ATCC 824 with xylose as carbon source. Riboflavin production increased from undetectable concentrations to ∼0.2 g L -1 (0.53 mM) when supplementing 60 mM NaAc. Of interest, solvents production and biomass yield were also promoted with fivefold acetone, 2.6-fold butanol, and 2.4-fold biomass adding NaAc. A kinetic metabolic model, developed to simulate ABE biosystem, with riboflavin production, revealed from a dynamic metabolic flux analysis (dMFA) simultaneous increase of riboflavin (ribA) and GTP (precursor of riboflavin) (PurM) synthesis flux rates under NaAc supplementation. The model includes 23 fluxes, 24 metabolites, and 72 kinetic parameters. It also suggested that NaAc condition has first stimulated the accumulation of intracellular metabolite intermediates during the acidogenic phase, which have then fed the solventogenic phase leading to increased ABE production. In addition, NaAc resulted in higher intracellular levels of NADH during the whole culture. Moreover, lower GTP-to-adenosine phosphates (ATP, ADP, AMP) ratio under NaAc supplemented condition suggests that GTP may have a minor role in the cell energetic metabolism compared to its contribution to riboflavin synthesis. © 2017 Wiley Periodicals, Inc.

  11. Effectiveness of Surface Cleaning and Disinfection in a Brazilian Healthcare Facility

    Science.gov (United States)

    Santos-Junior, Aires G.; Ferreira, Adriano M.; Frota, Oleci P.; Rigotti, Marcelo A.; Barcelos, Larissa da S.; Lopes de Sousa, Alvaro Francisco; de Andrade, Denise; Guerra, Odanir G.; R. Furlan, Mara C.

    2018-01-01

    Background: Failures in the processes of cleaning and disinfecting health service surfaces may result in the spread and transfer of pathogens that are often associated with healthcare-related infections and outbreaks. Aims: To assess the effectiveness of environmental surface cleaning and disinfection in a hospital clinic. Method: The study was conducted in a nursing ward with 45 beds. A total of 80 samples from five high-touch surfaces were evaluated before and after cleaning and disinfection, using the following methods: visual inspection, adenosine triphosphate bioluminescence assay, aerobic colony count, Staphylococcus aureus colony count, and evaluation of resistance to methicillin. The data analysis used nonparametric comparative and correlative tests to observe any differences in the pre- and post- cleaning and disinfection results for the surfaces assessed. Results: Effective cleaning and disinfection had a significant effect on only two surfaces when measured for the presence of adenosine triphosphate, the inner bathroom door handle (p=0.007) and the toilet bowl (p=0.01). When evaluated for Staphylococcus aureus colony count, the toilet flush handle also demonstrated a significant effect (p=0.04). Conclusion: The effectiveness of cleaning and disinfection of the surfaces tested was not satisfactory. An educational intervention is recommended for the cleaning and disinfection staff and the nursing team at the healthcare facility. Relevance to Clinical Practice: The data in the study revealed that daily hospital cleaning and disinfection in the sampled sites are not sufficient in medical and surgical wards. Hospital cleanliness must be reevaluated from the point of view of materials, such as an adequate supply of clean cloths, in addition to establishing more precise cleanliness protocols and accurate monitoring systems. PMID:29643951

  12. Effectiveness of Surface Cleaning and Disinfection in a Brazilian Healthcare Facility.

    Science.gov (United States)

    Santos-Junior, Aires G; Ferreira, Adriano M; Frota, Oleci P; Rigotti, Marcelo A; Barcelos, Larissa da S; Lopes de Sousa, Alvaro Francisco; de Andrade, Denise; Guerra, Odanir G; R Furlan, Mara C

    2018-01-01

    Failures in the processes of cleaning and disinfecting health service surfaces may result in the spread and transfer of pathogens that are often associated with healthcare-related infections and outbreaks. To assess the effectiveness of environmental surface cleaning and disinfection in a hospital clinic. The study was conducted in a nursing ward with 45 beds. A total of 80 samples from five high-touch surfaces were evaluated before and after cleaning and disinfection, using the following methods: visual inspection, adenosine triphosphate bioluminescence assay, aerobic colony count, Staphylococcus aureus colony count, and evaluation of resistance to methicillin. The data analysis used nonparametric comparative and correlative tests to observe any differences in the pre- and post- cleaning and disinfection results for the surfaces assessed. Effective cleaning and disinfection had a significant effect on only two surfaces when measured for the presence of adenosine triphosphate, the inner bathroom door handle ( p =0.007) and the toilet bowl ( p =0.01). When evaluated for Staphylococcus aureus colony count, the toilet flush handle also demonstrated a significant effect ( p =0.04). The effectiveness of cleaning and disinfection of the surfaces tested was not satisfactory. An educational intervention is recommended for the cleaning and disinfection staff and the nursing team at the healthcare facility. The data in the study revealed that daily hospital cleaning and disinfection in the sampled sites are not sufficient in medical and surgical wards. Hospital cleanliness must be reevaluated from the point of view of materials, such as an adequate supply of clean cloths, in addition to establishing more precise cleanliness protocols and accurate monitoring systems.

  13. Comparison of different techniques for disinfection of teeth internal space in preclinical teaching

    Directory of Open Access Journals (Sweden)

    Tabrizizadeh M.

    2009-12-01

    Full Text Available "nBackground and Aim: Extracted teeth used in preclinic should be disinfected. The aim of this study was to evaluate the effects of some disinfectants on microorganisms cultured from pulp chamber of extracted teeth."nMaterials and Methods: In this experimental study 54 intact human teeth were collected. After access cavity preparation, 10 8 B. streothermophillus endospors were inoculated into pulp chamber. Then cavities were sealed with a temporary restorative material. Teeth were divided into 5 groups of 10 each. The teeth were then stored in these disinfectants: 5.25% hypochlorite sodium, 5% Microten, 5% Deconex, 2% Glutaraldehyd, and 10% Formalin for 48 hours. Two teeth were autoclaved as negative controls and two were stored in normal saline as positive controls. The teeth were then sectioned in cervical area and cultured in Trypticase Soy Broth. After three days turbidity in tubes was evaluated. Statistical analysis was done by Fisher's exact test."nResults: None of these solutions were able to prevent microorganism growth in all samples; however, Formalin was better in six cases than that of other disinfectants. Differences between these five groups were not statistically significant (P=0.384."nConclusion: Sterilization of the teeth with autoclave is the only absolute method for disinfecting the root canals of extracted teeth and disinfectants are not reliable for this purpose.

  14. Effect of Gamma Radiation sterilization versus Disinfection on Removable Partial Dentures (Microbiological study)

    International Nuclear Information System (INIS)

    Mohammed, M.A.

    2011-01-01

    The aim of the study was to compare between the effectiveness of disinfection, using commercially available Fittydent super cleansing tablets versus sterilization, using gamma radiation on candidal growth in maxillary removable partial dentures. Methods: Fourteen partially edentulous subjects were selected according to specific criteria and divided equally and randomly into two groups; Group I: disinfection group and Group II: sterilization group. Conventional maxillary removable partial dentures were constructed for all subjects. The swab technique was used to collect the samples one month after denture delivery, immediately after disinfection/sterilization, and then one week, two weeks, three weeks, four weeks, and five weeks after disinfection/sterilization respectively. Bacteriological candidal colony count was performed using a manual contact colony counter. Results: Both methods (disinfection and sterilization) led to a noticeable decrease in the candidal count. However this decrease was highly and markedly evident in Group II as compared to Group I. Infact, no candidal growth was recorded for group II immediately after strerilization and was maintained for two more weeks. Statistical analysis revealed highly significant differences between the two groups. Conclusions: Both methods were effective in decreasing the number of Candida albicans adhering to the denture. However, sterilization using Gamma radiation had a more superior immediate, as well as, long term efficiency as compared to disinfection using Fittydent super cleansing tablets.

  15. Evaluation of the Antimicrobial Effects of Various Methods to Disinfect Toothbrushes Contaminated with Streptococcus mutans

    Directory of Open Access Journals (Sweden)

    Foroogh Amirabadi

    2016-11-01

    Full Text Available Toothbrushes sterilization has strongly taken into consideration in order of prohibiting of transmission and reinfection. The differences of materials, procedures and duration, made the problem more complicated. Our objective of the present research was assessment of antibacterial effects of different procedures which are used for disinfection of those toothbrushes which are infected to Streptococcus mutans. 144 fresh toothbrushes were immersed in a 0.5 McFarland culture of S. mutans for 15 minutes. The toothbrushes were then classified into 8 groups ( 6 in each group according to their disinfecting procedure including White vinegar 50%, Sodium hypochlorite %1, Ethyl alcohol and Povidone Iodine 10%. The disinfecting procedures which used were Microwave and Dishwasher. Bacterial cultivation was done and microbial colonies had been counted before toothbrushes were exposed to the above disinfectants. After exposure of toothbrushes to above disinfectants for 1, 5 and 10 minutes, the colonies were recounted. SPSS ver.19 (Kruskal–Wallis Test was used for statistical analysis. Bacterial cultures of samples at Chlorhexidine group (negative control were negative and White vinegar did not make a considerable sense. On the other hand, Sodium hypochlorite %1, Ethyl alcohol , Povidone Iodine 10% and dishwasher decreased the numbers of S. mutans considerably (p< %5. Microwave by increasing the time of exposition, decreased the numbers of microbes but it was not statistically significant. Povidone Iodine 10%, Sodium hypochlorite %1 and Ethyl alcohol, could be effective in disinfection of toothbrushes against S. mutans if be used for 10 minutes.

  16. [Improvement of effectivity of photo disinfection of water from bacterial contaminants in the presence of heterogeneous sensitizers based on phthalocyanines grafted to aminopropyl silicagel].

    Science.gov (United States)

    Maksimkina, T N; Artemova, T Z; Kuznetsova, N A; Sinitsyna, O O; Gipp, E K; Zagaĭnova, A V; Butorina, N N; Iuzhakova, O A; Krasniak, A V

    2012-01-01

    The possibility of using 12 heterogeneous sensitizers (HS) based on phthalocyanines covalently grafted to aminopropyl silicagel for disinfection of water from bacteria has been studied. For reliable water quality control the technique of performing bacteriological analysis in the presence of HS beads in the sample has been elaborated. The conditions increasing the efficiency of photo disinfection in the presence of HS were studied. Algorithm for estimation of photo disinfectant effect of HS against bacteria was substantiated. Obtained data confirm the perspective of further studies on the substantiation of the possibility of the application of HS for water disinfection.

  17. Copper disinfection ban causes storm.

    Science.gov (United States)

    Lester, Alan

    2013-05-01

    Since 1 February this year, under the EU's Biocidal Products Directive, it has been illegal to sell or use water treatment systems that use elemental copper, a practice employed historically by a significant number of UK healthcare facilities to combat Legionella. Alan Lester, managing director of specialist supplier of 'environmentally-friendly' water treatment systems, Advanced Hydro, says the ban has caused 'a storm of giant proportion,' with advocates of copper ion-based treatment systems arguing that this disinfection method dates back 3,000 years to Egyptian times, making it an 'undoubtedly proven' technology. Here he explains why the ban came into force, considers why the UK's Health and Safety Executive (HSE) is seeking a derogation, looks at the ban's likely impact, and gives a personal viewpoint on the 'pros and cons' of some of the alternative treatment technologies, including a titanium dioxide-based system marketed by Advanced Hydro itself in the UK.

  18. ASSESSMENT OF THE EFFICIENCY OF DISINFECTION METHOD ...

    African Journals Online (AJOL)

    eobe

    ABSTRACT. The efficiencies of three disinfection methods namely boiling, water guard and pur purifier were assessed. ... Water is an indispensable resource for supporting life systems [2- ...... developing country context: improving decisions.

  19. Enhancement of ultraviolet water disinfection process

    African Journals Online (AJOL)

    grabi-1

    2013-05-15

    May 15, 2013 ... disinfected water distribution systems, including. Legionella .... soft agar, mixed, incubated at room temperature for 2 min and poured onto the ... The determination of a log increase methodology was employed to quantify the ...

  20. Evaluation of different disinfectants on the performance of an on-meter dosed amperometric glucose-oxidase-based glucose meter.

    Science.gov (United States)

    Sarmaga, Don; Dubois, Jeffrey A; Lyon, Martha E

    2011-11-01

    Off-meter dosed photometric glucose-oxidase-based glucose meters have been reported to be susceptible to interference by hydrogen-peroxide-based disinfecting agents. The objective of this study was to determine if a single application of hydrogen-peroxide-containing Accel® wipe to disinfect an on-meter dosed amperometric glucose-oxidase-based glucose meter will influence its performance. The performance of five on-meter dosed amperometric glucose-oxidase-based glucose meters was determined before and after disinfecting the devices with a single application of either CaviWipes® (14.3% isopropanol and 0.23% diisobutyl-phenoxy-ethoxyethyl dimethyl benzyl ammonium chloride) or Accel (0.5% hydrogen peroxide) wipes. Replicate glucose measurements were conducted before disinfecting the devices, immediately after disinfecting, and then 1 and 2 min postdisinfecting, with measurements in triplicate. Analysis was sequentially completed for five different meters. Results were analyzed by a two-way analysis of variance (Analyze-it software). No clinical ( .05) in glucose concentration were detected when the on-meter dosed amperometric glucose-oxidase-based glucose meters were disinfected with either CaviWipes or Accel wipes and measured immediately or 1 or 2 min postdisinfecting. No clinically significant difference in glucose concentration was detected between meters (glucose oxidase amperometric-based glucose meters are not analytically susceptible to interference by a single application of hydrogen-peroxide-containing Accel disinfectant wipes. © 2011 Diabetes Technology Society.

  1. PROBIOTIC CLEANING PREPARATIONS VERSUS CHEMICAL DISINFECTANTS

    Directory of Open Access Journals (Sweden)

    W. Luepcke

    2017-12-01

    Full Text Available Probiotic detergents are increasingly used and are a real alternative for limiting the use of chemical cleaners, chemical disinfectants and antibiotics. They therefore have a great future because they contribute to animal health, to the hygienic production of food products of animal origin and to their harmlessness and to consumer health and environmental protection where they even have a beneficial effect on the microflora apart from chemical disinfectants that have a negative impact and destroy the beneficial microflora.

  2. Automation of air disinfection and lighting in agricultural buildings

    Directory of Open Access Journals (Sweden)

    L. Yu. Yuferev

    2017-01-01

    Full Text Available The article describes the urgency of this problem and modern ways of its solving. Modern disinfection and lighting systems are not developed enough. The authors proposed to automate the system of disinfection, dust removal and lighting in the farm building. We developed algorithm on the basis of which the universal program in the programming language C ++ was written. Assembled the microprocessor set ARDUINO. The program is included in the microprocessor ATMEGA, which is part of ARDUINO. As a basis for the disinfection system, a two-component ARUF device was used, which includes two decontaminating components: an ultraviolet lamp and an aerosol dispenser. Each of the algorithms (lighting and disinfection consists of 3 parts: data collection and analysis, control, data output to the display. The sequence of 3 parts is 1 cycle, then it repeated. In the first part on the basis of indications of sensors assignment to variables of some values was carried out. In the second part, based on the values of the variables, the decontamination and lighting devices are controlled. In the third part due to changing the screen number, variable, it is possible to switch the display and view the status of the installation and external parameters. The program, written on the basis of algorithms, is universal and suitable for almost any poultry and livestock buildings. All parameters (the time of the beginning and completion of the ARUV operation within 24 hours, the daily time of the illumination of a certain cycle, the maximum and minimum humidity, the duration of each cycle used for control and management are variables. Operator can set the items using the display in the menu.

  3. Predictors of stethoscope disinfection among pediatric health care providers.

    Science.gov (United States)

    Muniz, Jeanette; Sethi, Rosh K V; Zaghi, Justin; Ziniel, Sonja I; Sandora, Thomas J

    2012-12-01

    Stethoscopes are contaminated with bacteria, but predictors of stethoscope disinfection frequency are unknown. We sought to describe health care provider stethoscope disinfection attitudes and practices and determine predictors of frequent disinfection. We used an anonymous online survey of nurses, nurse practitioners, and physicians at a pediatric hospital. We assessed frequency and methods of disinfection, perceptions of contamination, and barriers to disinfection. Multivariate logistic regression models were used to identify independent predictors of disinfecting after every use. One thousand four hundred one respondents completed the survey: 76% believed that infection transmission occurs via stethoscopes, but only 24% reported disinfecting after every use. In multivariate analyses, belief that infection transmission occurs via stethoscopes significantly increased the odds of disinfection after every use (odds ratio [OR], 2.06 [95% confidence interval (CI): 1.38-3.06]). The odds of disinfection after every use were significantly decreased in those who perceived the following barriers: lack of time (OR, 0.31 [95% CI: 0.18-0.54]), lack of access to disinfection material (OR, 0.41 [95% CI: 0.29-0.57]), or lack of visual reminders to disinfect (OR, 0.22 [95% CI: 0.14-0.34]). Only a minority of pediatric health care providers reported disinfecting their stethoscopes after every use. Increasing access to disinfection materials and visual reminders in health care facilities may improve stethoscope disinfection practices. Copyright © 2012 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Mosby, Inc. All rights reserved.

  4. Study of the Interactions Between Bacteriophage phiIPLA-RODI and Four Chemical Disinfectants for the Elimination of Staphylococcus aureus Contamination

    Directory of Open Access Journals (Sweden)

    Seila Agún

    2018-02-01

    Full Text Available Bacteriophages are currently considered as a promising alternative to antibiotics and disinfectants. However, the use of phages in different clinical and industrial settings will involve their exposure to other disinfectants. As a result, the outcome of the phage treatment will depend on two aspects derived from such interactions. On the one hand, the susceptibility of the phage to disinfectants at the concentrations used for disinfection and at lower residual concentrations needs to be determined. Additionally, the existence of synergistic or antagonistic interactions between phages and disinfectants would also affect the potential success of phage biocontrol applications. Here, we tested these effects for the antistaphylococcal phage phiIPLA-RODI by using four different disinfectants: benzalkonium chloride, triclosan, chlorhexidine and hydrogen peroxide. Our results highlight the differences between disinfectants regarding their effect on phage survival and antimicrobial properties. For instance, our data suggests that, out of the four disinfectants used, benzalkonium chloride would be the most adequate to use in settings where phages are to be applied. Nonetheless, this preliminary analysis grants the need for further studies with a larger number of disinfectants for the development of a phiIPLA-RODI-based product.

  5. Genotoxicity of drinking water treated with different disinfectants and effects of disinfection conditions detected by umu-test.

    Science.gov (United States)

    Nie, Xuebiao; Liu, Wenjun; Zhang, Liping; Liu, Qing

    2017-06-01

    The genotoxicity of drinking water treated with 6 disinfection methods and the effects of disinfection conditions were investigated using the umu-test. The pretreatment procedure of samples for the umu-test was optimized for drinking water analysis. The results of the umu-test were in good correlation with those of the Ames-test. The genotoxicity and production of haloacetic acids (HAAs) were the highest for chlorinated samples. UV+chloramination is the safest disinfection method from the aspects of genotoxicity, HAA production and inactivation effects. For chloramination, the effects of the mass ratio of Cl 2 to N of chloramine on genotoxicity were also studied. The changes of genotoxicity were different from those of HAA production, which implied that HAA production cannot represent the genotoxic potential of water. The genotoxicity per chlorine decay of chlorination and chloramination had similar trends, indicating that the reaction of organic matters and chlorine made a great contribution to the genotoxicity. The results of this study are of engineering significance for optimizing the operation of waterworks. Copyright © 2016. Published by Elsevier B.V.

  6. Comparing the disinfecting efficacies of Micro 10, Deconex, Alprocid and Microzid af on the microorganisms on radiographic equipments

    Directory of Open Access Journals (Sweden)

    Zahed Mohammadi

    2008-08-01

    Full Text Available Background and aims. The exposure and processing of dental radiographs are not routinely associated with the spatter of blood or saliva; however, infection control is still an issue resulting from contaminated equipment, supplies, film packets or cassettes. This study aimed at comparing the efficacy of four commercially available disinfectants on microorganisms present on the equipment of radiology department. Materials and methods. Samples from twelve sites of the radiology department were collected using a sterile swab smeared with normal saline, which was then dipped in a test tube. Experimental surfaces were then disinfected by the spray-wipe-spray method using one of Micro 10, Deconex, Alprocid or Microzid AF disinfectants, followed by resampling. The samples were subsequently cultured on blood agar and EMB plates and the colonies were counted. Isolates were identified by biochemical tests. For statistical analysis, Wilcoxon signed ranks test, Kruskal-Wallis, Chi-square and Fisher exact tests were used. Results. Staphylococcus aureus and coagulase-negative staphylococci had the highest and Lactobacillus spp. had the lowest prevalence before disinfection. There were significant differences between the cfu/mL of bacteria before and after disinfection with any of the four disinfectant solutions. There was a significant difference between efficacy of Deconex and Alprocid (P = 0.014, Deconex and Microzid AF (P = 0.001, and Deconex and Micro 10 (P = 0.001. Conclusion. According to the results, Deconex has the highest disinfectant efficacy compared to other solutions.

  7. Hospital disinfection: efficacy and safety issues.

    Science.gov (United States)

    Dettenkofer, Markus; Block, Colin

    2005-08-01

    To review recent publications relevant to hospital disinfection (and cleaning) including the reprocessing of medical instruments. The key question as to whether the use of disinfectants on environmental surfaces rather than cleaning with detergents only reduces nosocomial infection rates still awaits conclusive studies. New disinfectants, mainly peroxygen compounds, show good sporicidal properties and will probably replace more problematical substances such as chlorine-releasing agents. The safe reprocessing of medical devices requires a well-coordinated approach, starting with proper cleaning. New methods and substances show promising activity for preventing the transmission of prions. Different aspects of virus inactivation have been studied, and the transmissibility, e.g. of norovirus, shows the need for sound data on how different disinfectant classes perform. Biofilms or other forms of surface-adherent organisms pose an extraordinary challenge to decontamination. Although resistance to biocides is generally not judged to be as critical as antibiotic resistance, scientific data support the need for proper use, i.e. the avoidance of widespread application, especially in low concentrations and in consumer products. Chemical disinfection of heat-sensitive instruments and targeted disinfection of environmental surfaces are established components of hospital infection control. To avoid danger to staff, patients and the environment, prudent use as well as established safety precautions are required. New technologies and products should be evaluated with sound methods. As emerging resistant pathogens will challenge healthcare facilities in the future even more than at present, there is a need for well-designed studies addressing the role of disinfection in hospital infection control.

  8. Inactivation of an enterovirus by airborne disinfectants

    Science.gov (United States)

    2013-01-01

    Background The activity of airborne disinfectants on bacteria, fungi and spores has been reported. However, the issue of the virucidal effect of disinfectants spread by fogging has not been studied thoroughly. Methods A procedure has been developed to determine the virucidal activity of peracetic acid-based airborne disinfectants on a resistant non-enveloped virus poliovirus type 1. This virus was laid on a stainless carrier. The products were spread into the room by hot fogging at 55°C for 30 minutes at a concentration of 7.5 mL.m-3. Poliovirus inoculum, supplemented with 5%, heat inactivated non fat dry organic milk, were applied into the middle of the stainless steel disc and were dried under the air flow of a class II biological safety cabinet at room temperature. The Viral preparations were recovered by using flocked swabs and were titered on Vero cells using the classical Spearman-Kärber CPE reading method, the results were expressed as TCID50.ml-1. Results The infectious titer of dried poliovirus inocula was kept at 105 TCID50.mL-1 up to 150 minutes at room temperature. Dried inocula exposed to airborne peracetic acid containing disinfectants were recovered at 60 and 120 minutes post-exposition and suspended in culture medium again. The cytotoxicity of disinfectant containing medium was eliminated through gel filtration columns. A 4 log reduction of infectious titer of dried poliovirus inocula exposed to peracetic-based airborne disinfectant was obtained. Conclusion This study demonstrates that the virucidal activity of airborne disinfectants can be tested on dried poliovirus. PMID:23587047

  9. Residual structure of Streptococcus mutans biofilm following complete disinfection favors secondary bacterial adhesion and biofilm re-development.

    Directory of Open Access Journals (Sweden)

    Tatsuya Ohsumi

    Full Text Available Chemical disinfection of oral biofilms often leaves biofilm structures intact. This study aimed to examine whether the residual structure promotes secondary bacterial adhesion. Streptococcus mutans biofilms generated on resin-composite disks in a rotating disc reactor were disinfected completely with 70% isopropyl alcohol, and were again cultured in the same reactor after resupplying with the same bacterial solution. Specimens were subjected to fluorescence confocal laser scanning microscopy, viable cell counts and PCR-Invader assay in order to observe and quantify secondarily adhered cells. Fluorescence microscopic analysis, particularly after longitudinal cryosectioning, demonstrated stratified patterns of viable cells on the disinfected biofilm structure. Viable cell counts of test specimens were significantly higher than those of controls, and increased according to the amount of residual structure and culture period. Linear regression analysis exhibited a high correlation between viable and total cell counts. It was concluded that disinfected biofilm structures favored secondary bacterial adhesion.

  10. EXPERIMENTAL COMPARISON OF THE AEROSOL METHOD OF DISINFECTION OF AIR AND SURFACES CONTAMINATED BY M. TUBERCULOSIS

    Directory of Open Access Journals (Sweden)

    V. V. Kuzin

    2018-01-01

    instead of disinfectant for control tests treating the tests objects contaminated in the same manner.Results. The good disinfection properties of Green Dez aerosol were proved during the simulation of M. tuberculosis, H37Rv strain, disinfection on the surfaces and in the air.The efficiency analysis of the aerosol method of disinfection proved the reduction of disinfectant consumption by 4-5 times versus wiping and irrigation, due to this the aerosol treatment can be regarded as a safer and more environmentally friendly method.The finely dispersed disinfectant aerosol, produced by MNC, effectively decontaminated the whole space, including the remote and hard-to-reach places. Full automation of disinfection implies no human presence providing high safety of disinfection

  11. Comparative experimental study on municipal wastewater disinfection with ozone and peracetic acid; Indagine sperimentale comparata sulla disinfezione di acque reflue urbane con ozono e acido peracetico

    Energy Technology Data Exchange (ETDEWEB)

    Andreottola, G.; Bertola, P.; Ziglio, G. [Trento Univ. (Italy). Dip. di Ingegneria Civile Ambientale

    1996-04-01

    The results of a pilot experimental study on the disinfection of treated municipal wastewater to be used in agriculture are presented. A comparative evaluation has been carried out on two parallel pilot-scale disinfection plants using respectively ozone and peracetic acid. After a preliminary sand filtration pilot unit. Both processes showed the capability of meeting the Italian standards for agricultural reuse, but the disinfection process with ozone required much higher doses than the one with peracetic acid, probably because of the higher reactivity of ozone, if compared to peracetic acid with the organic matter present in wastewater. Further research is needed in order to evaluate the efficiency of peracetic acid applied to microorganism different from the bacterial ones and to identify nature and consequences of possible disinfection by products.

  12. A practical evaluation of detergent and disinfectant solutions on ...

    African Journals Online (AJOL)

    Student01

    2012-01-06

    Jan 6, 2012 ... Nine sanitation chemical solutions: benzalkonium chloride, sodium hypochlorite, nitric ... cleaning and disinfection in reducing selected bacteria levels as required by ..... bacteria targeted during disinfection are attached to a.

  13. Basic Information about Chloramines and Drinking Water Disinfection

    Science.gov (United States)

    Chloramines are disinfectants used to treat drinking water. Chloramines are most commonly formed when ammonia is added to chlorine to treat drinking water. Chloramines provide longer-lasting disinfection as the water moves through pipes to consumers.

  14. Study and application of herbal disinfectants in China.

    Science.gov (United States)

    Chen, Zhao-Bin

    2004-12-01

    Disinfection means killing or removing pathogenic microorganisms in media to realize a harmless process. A disinfectant, which is also referred to as a disinfection medicine in relevant regulations, is the medicine used to kill microorganisms for the purpose of disinfection. The disinfectants prepared from plants (including traditional Chinese herbal medicines) and the extracts thereof are called herbal disinfectants. China has a long history of using herbal disinfectants. As early as in 533 A.D., the use of Cornel to sterilize well water was recorded in Necessary Techniques for Qi People by Jia Enxie of the Beiwei Dynasty. During the Dragon Boat Festival, people often use fumigants made of traditional Chinese herbal medicines like Chinese Atractylodes, Argy Wormwood Leaf and Red Arsenic Sulfide to smoke their houses, so as to ward off plagues and drive away evils. In fact this is now a kind of disinfection practice.

  15. Disinfection for small water supplies: a technical guide

    CSIR Research Space (South Africa)

    Solsona, F

    1990-01-01

    Full Text Available This guide will present some disinfection systems, which will be useful in supporting disinfection programmes. The description of the different systems will provide a guideline for the selection of equipment base on balancing the simplicity...

  16. Effect of chemical disinfectants and accelerated aging on maxillofacial silicone elastomers: An In vitro Study

    Directory of Open Access Journals (Sweden)

    Anna Serene Babu

    2018-01-01

    Full Text Available Context: Maxillofacial prostheses need frequent refabrication due to degradation of color and deterioration of physical properties of the elastomer. Aims: This study attempted to evaluate the change in color stability, Shore A hardness, and surface roughness of two maxillofacial silicones, A-2186 and Cosmesil M511, when submitted to chemical disinfection and accelerated aging. Settings and Design: This was a comparative in vitro study. Subjects and Methods: The materials included two silicone elastomers – A-2186 and Cosmesil M511 (Factor II Incorporated – functional intrinsic red pigment and three disinfectants – Fittydent tablet, chlorhexidine gluconate 4%, and neutral soap. The specimens in each group of elastomer were evaluated initially for color, hardness, and surface roughness, which were further divided into subgroups and subjected to disinfection and accelerated aging. The evaluation of color was performed with the help of an ultraviolet reflectance spectrophotometer. Shore A hardness was evaluated using a durometer and surface roughness, with a digital roughness tester followed by scanning electron microscopy analysis. Statistical Analysis Used: Analysis of variance and Tukey's multiple comparison test were used for statistical analysis. Results: Accelerated aging caused a significant decrease in color, increase in Shore A hardness, and variation in surface roughness in both silicone elastomer groups. Chemical disinfection presented significant changes in color and surface roughness whereas no significant effect on Shore hardness, irrespective of the disinfectant used. Conclusions: The maxillofacial silicone elastomers presented deterioration in color, hardening, and significant variations in surface roughness when subjected to chemical disinfection and accelerated aging, which provides a valid baseline for future research.

  17. The effect of disinfectant solutions on the hardness of acrylic resin denture teeth.

    Science.gov (United States)

    Pavarina, A C; Vergani, C E; Machado, A L; Giampaolo, E T; Teraoka, M T

    2003-07-01

    This investigation studied the effects of disinfectant solutions on the hardness of acrylic resin denture teeth. The occlusal surfaces of 64 resin denture teeth were ground flat with abrasives up to 400-grit silicon carbide paper. Measurements were made after polishing and after the specimens were stored in water at 37 degrees C for 48 h. The specimens were then divided into four groups and immersed in chemical disinfectants (4% chlorhexidine; 1% sodium hypochlorite and sodium perborate) for 10 min. The disinfection methods were performed twice to simulate clinical conditions and hardness measurements were made. Specimens tested as controls were immersed in water during the same disinfection time. Eight specimens were produced for each group. After desinfection procedures, testing of hardness was also performed after the samples were stored at 37 degrees C for 7, 30, 60, 90 and 120 days. Data were analysed using two-way analysis of variance (anova) and Tukey's test at 95% confidence level. According to the results, no significant differences were found between materials and immersion solutions (P > 0.05). However, a continuous decrease in hardness was noticed after ageing (P surfaces of both acrylic resin denture teeth softened upon immersion in water regardless the disinfecting solution.

  18. Validation of a simple method for predicting the disinfection performance in a flow-through contactor.

    Science.gov (United States)

    Pfeiffer, Valentin; Barbeau, Benoit

    2014-02-01

    Despite its shortcomings, the T10 method introduced by the United States Environmental Protection Agency (USEPA) in 1989 is currently the method most frequently used in North America to calculate disinfection performance. Other methods (e.g., the Integrated Disinfection Design Framework, IDDF) have been advanced as replacements, and more recently, the USEPA suggested the Extended T10 and Extended CSTR (Continuous Stirred-Tank Reactor) methods to improve the inactivation calculations within ozone contactors. To develop a method that fully considers the hydraulic behavior of the contactor, two models (Plug Flow with Dispersion and N-CSTR) were successfully fitted with five tracer tests results derived from four Water Treatment Plants and a pilot-scale contactor. A new method based on the N-CSTR model was defined as the Partially Segregated (Pseg) method. The predictions from all the methods mentioned were compared under conditions of poor and good hydraulic performance, low and high disinfectant decay, and different levels of inactivation. These methods were also compared with experimental results from a chlorine pilot-scale contactor used for Escherichia coli inactivation. The T10 and Extended T10 methods led to large over- and under-estimations. The Segregated Flow Analysis (used in the IDDF) also considerably overestimated the inactivation under high disinfectant decay. Only the Extended CSTR and Pseg methods produced realistic and conservative predictions in all cases. Finally, a simple implementation procedure of the Pseg method was suggested for calculation of disinfection performance. Copyright © 2013 Elsevier Ltd. All rights reserved.

  19. Characterization of Cleaning and Disinfecting Tasks and Product Use Among Hospital Occupations

    Science.gov (United States)

    Saito, Rena; Virji, M. Abbas; Henneberger, Paul K.; Humann, Michael J.; LeBouf, Ryan F.; Stanton, Marcia L.; Liang, Xiaoming; Stefaniak, Aleksandr B.

    2016-01-01

    Background Healthcare workers have an elevated prevalence of asthma and related symptoms associated with the use of cleaning/disinfecting products. The objective of this study was to identify and characterize cleaning/disinfecting tasks and products used among hospital occupations. Methods Workers from 14 occupations at five hospitals were monitored for 216 shifts, and work tasks and products used were recorded at five-minute intervals. The major chemical constituents of each product were identified from safety data sheets. Results Cleaning and disinfecting tasks were performed with a high frequency at least once per shift in many occupations. Medical equipment preparers, housekeepers, floor strippers/waxers, and endoscopy technicians spent on average 108–177 min/shift performing cleaning/disinfecting tasks. Many occupations used products containing amines and quaternary ammonium compounds for > 100 min/shift. Conclusions This analysis demonstrates that many occupations besides housekeeping incur exposures to cleaning/disinfecting products, albeit for different durations and using products containing different chemicals. PMID:25351791

  20. Chlorination and chloramination of aminophenols in aqueous solution: oxidant demand and by-product formation.

    Science.gov (United States)

    Mehrez, O Abou; Dossier-Berne, F; Legube, B

    2015-01-01

    Chlorination and monochloramination of aminophenols (AP) were carried out in aqueous solution at 25°C and at pH 8.5. Oxidant demand and disinfection by-product formation were determined in excess of oxidant. Experiments have shown that chlorine consumption of AP was 40-60% higher than monochloramine consumption. Compared with monochloramination, chlorination of AP formed more chloroform and haloacetic acids (HAA). Dichloroacetic acid was the major species of HAA. Chloroform and HAA represented, respectively, only 1-8% and 14-15% of adsorbable organic halides (AOX) by monochloramination but up to 29% and 39% of AOX by chlorination.

  1. OPTIMAL SCHEDULING OF BOOSTER DISINFECTION IN WATER DISTRIBUTION SYSTEMS

    Science.gov (United States)

    Booster disinfection is the addition of disinfectant at locations distributed throughout a water distribution system. Such a strategy can reduce the mass of disinfectant required to maintain a detectable residual at points of consumption in the distribution system, which may lea...

  2. Chemical aspects of peracetic acid based wastewater disinfection ...

    African Journals Online (AJOL)

    Peracetic acid (PAA) has been studied for wastewater disinfection applications for some 30 years and has been shown to be an effective disinfectant against many indicator microbes, including bacteria, viruses, and protozoa. One of the key advantages compared to, e.g., chlorine is the lack of harmful disinfection ...

  3. 40 CFR 141.172 - Disinfection profiling and benchmarking.

    Science.gov (United States)

    2010-07-01

    ... benchmarking. 141.172 Section 141.172 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... Disinfection-Systems Serving 10,000 or More People § 141.172 Disinfection profiling and benchmarking. (a... sanitary surveys conducted by the State. (c) Disinfection benchmarking. (1) Any system required to develop...

  4. Effects of some antiseptics and disinfectants on Staphylococcus ...

    African Journals Online (AJOL)

    A total of 6 antiseptics and disinfectants at varying concentrations (20% - 100%) and contact time (10-60 minutes) were tested for the efficacy in the reduction of Staphylococcus aureus isolated from the hands of volunteers. Disinfectant 1 was the most effective disinfectant being bactericidal to S. aureus at 100% ...

  5. 9 CFR 91.41 - Cleaning and disinfecting of aircraft.

    Science.gov (United States)

    2010-01-01

    ... of this chapter. The time at which the cleaning and disinfection is performed must be approved by the inspector, who will give approval only if he or she determines that the cleaning and disinfection will be... time, the inspector shall determine whether further cleaning and disinfection are necessary. The...

  6. Technical considerations during disinfection by UV

    International Nuclear Information System (INIS)

    Ekhtiarzadeh, Z.; Sadeghpur, H.

    2002-01-01

    The use of new methods for treatment of water and wastewater in the country is one the rise and therefore the theoretical and practical knowledge of the industry's engineers should increase simultaneously. Ultraviolet is one of the new technologies used both for treatment of water as well as wastewater. The UV disinfection system consists of different components such as the lamp, ballast and the lamp fixtures. Each has a specification, which should be taken into account prior to design, order and purchase. The subject of price is also among the important considerations. The article presents figures cost comparison in various sections. It does not try to either approve or reject other disinfection systems such as chlorination, but the writer believes that any method should find its own practice and conditions of use, and the disinfection system designers should opt for the best system suited to their plans and avoid limiting themselves to a single one

  7. Intracellular mechanisms of solar water disinfection

    Science.gov (United States)

    Castro-Alférez, María; Polo-López, María Inmaculada; Fernández-Ibáñez, Pilar

    2016-12-01

    Solar water disinfection (SODIS) is a zero-cost intervention measure to disinfect drinking water in areas of poor access to improved water sources, used by more than 6 million people in the world. The bactericidal action of solar radiation in water has been widely proven, nevertheless the causes for this remain still unclear. Scientific literature points out that generation of reactive oxygen species (ROS) inside microorganisms promoted by solar light absorption is the main reason. For the first time, this work reports on the experimental measurement of accumulated intracellular ROS in E. coli during solar irradiation. For this experimental achievement, a modified protocol based on the fluorescent probe dichlorodihydrofluorescein diacetate (DCFH-DA), widely used for oxidative stress in eukaryotic cells, has been tested and validated for E. coli. Our results demonstrate that ROS and their accumulated oxidative damages at intracellular level are key in solar water disinfection.

  8. Activity and action screening of selected disinfectants

    Directory of Open Access Journals (Sweden)

    Kateřina Balharová

    2006-01-01

    Full Text Available This research work is aimed to monitoring of selected disinfectants´activity in operational conditions. Hereby there have been monitored two acidic disinfectants Despon K and Mikasan D, which have had-by their producer-stated different recommended concentration. These solutions were monitored in viewpoint of their activity at different temperature, time of circulation, pH and water hardness. In this work there were measured pH of solutions in unloaded medium to be compared with pH of solutions in loaded medium and this measuring was carried out regularly each week within a one month period. During this period there was also monitored total plate count (TPC, which was stated in the dairy, where samples were taken two-times monthly. It has been found, that the disinfectants Mikasan D and Mikal 94D are effective even by high water hardness.

  9. Photoreactivation Study of Wastewater Treatment Effluent Disinfected by UV-disinfection for Water Reuse

    International Nuclear Information System (INIS)

    Yoon, C.G.; Jung, K.W.; Ham, J.H.; Jeon, J.H.

    2003-01-01

    Photoreactivation of microorganism following UV-disinfection is one of the research topics of interest in assessing the UV-disinfection performance. Apparent photoreactivation was examined under fluorescent lamp and solar radiation as well as in darkness. Total coliform, fecal coliform, and Escherichia coli were used as indicator microorganisms, and their concentration of 10~30 MPN/100mL increased to the level of 100 MPN/100mL after 24 hours, which implied that part of damaged microorganisms by UV-disinfection might be repairable with time

  10. Disinfection efficiency of peracetic acid (PAA): inactivation of coliphages and bacterial indicators in a municipal wastewater plant.

    Science.gov (United States)

    Zanetti, F; De Luca, G; Sacchetti, R; Stampi, S

    2007-11-01

    The aim of the study was to assess the efficiency of low doses of peracetic acid against viral and bacterial indicators in wastewater and to evaluate if the treatment allows regulatory requirements to be satisfied. A total of 31 samplings were carried out, each involving the collection of secondary effluent and of effluent disinfected with 1.2 or 1.5 mg l(-1) of peracetic acid (contact time 20 minutes). In each sample were measured: somatic coliphages, F-specific RNA bacteriophages, Escherichia coli, total and faecal coliforms, enterococci. Peracetic acid disinfection showed significant differences between the reductions of the microorganisms tested: E. coli showed the highest reduction (1.78 and 2.43 Log respectively with 1.2 and 1.5 mg l(-1) of peracetic acid) and phages the lowest (ranging between 0.52 and 0.60 Log). Only a concentration of 1.5 mg l(-1) of peracetic acid would enable the effluent to be discharged into surface waters in compliance with Italian regulations. The variability of microbial resistance against the peracetic acid disinfection treatment, underlines the importance of assessing disinfection efficiency by using more than one indicator microorganism. The detection of E. coli could be usefully accompanied by tests for more resistant microorganisms such as enterococci or coliphages. In conclusion, peracetic acid can be used for the disinfection of effluents even at low doses, with the advantage of reducing costs and preventing the formation of significant amounts of genotoxic by-products.

  11. TIC-Tox: A preliminary discussion on identifying the forcing agents of DBP-mediated toxicity of disinfected water.

    Science.gov (United States)

    Plewa, Michael J; Wagner, Elizabeth D; Richardson, Susan D

    2017-08-01

    The disinfection of drinking water is a major public health achievement; however, an unintended consequence of disinfection is the generation of disinfection by-products (DBPs). Many of the identified DBPs exhibit in vitro and in vivo toxicity, generate a diversity of adverse biological effects, and may be hazards to the public health and the environment. Only a few DBPs are regulated by several national and international agencies and it is not clear if these regulated DBPs are the forcing agents that drive the observed toxicity and their associated health effects. In this study, we combine analytical chemical and biological data to resolve the forcing agents associated with mammalian cell cytotoxicity of drinking water samples from three cities. These data suggest that the trihalomethanes (THMs) and haloacetic acids may be a small component of the overall cytotoxicity of the organic material isolated from disinfected drinking water. Chemical classes of nitrogen-containing DBPs, such as the haloacetonitriles and haloacetamides, appear to be the major forcing agents of toxicity in these samples. These findings may have important implications for the design of epidemiological studies that primarily rely on the levels of THMs to define DBP exposure among populations. The TIC-Tox approach constitutes a beginning step in the process of identifying the forcing agents of toxicity in disinfected water. Copyright © 2017. Published by Elsevier B.V.

  12. Evaluation of bactericidal efficacy of silver ions on Escherichia coli for drinking water disinfection.

    Science.gov (United States)

    Pathak, Satya P; Gopal, K

    2012-07-01

    The purpose of this study is the development of a suitable process for the disinfection of drinking water by evaluating bactericidal efficacy of silver ions from silver electrodes. A prototype of a silver ioniser with silver electrodes and control unit has been fabricated. Silver ions from silver electrodes in water samples were estimated with an atomic absorption spectrophotometer. A fresh culture of Escherichia coli (1.75 × 10(3) c.f.u./ml) was exposed to 1, 2, 5, 10 and 20 ppb of silver ions in 100 ml of autoclaved tap water for 60 min. The effect of different pH and temperatures on bactericidal efficacy was observed at constant silver ion concentration (5 ppb) and contact time of 30 min. The maximum bactericidal activity (100%) was observed at 20 ppb of silver ion concentration indicating total disinfection after 20 min while minimum bactericidal activity (25%) was observed after 10 min at 01 ppb of silver ions. Likewise, 100% bactericidal activity was noticed with 2, 5 and 10 ppb of silver ions after 60, 50 and 40 min, respectively. Bactericidal activity at pH 5, 6, 7, 8 and 9 was observed at 79.9%, 79.8%, 80.5%, 100% and 100%, respectively, whereas it was 80.4%, 88.3%, 100%, 100% and 100% at 10°C, 20°C, 30°C, 40°C and 50°C, respectively. The findings of this study revealed that very low concentrations of silver ions at pH 8-9 and temperature >20°C have bactericidal efficacy for total disinfection of drinking water. Silver ionisation is suitable for water disinfection and an appropriate alternative to chlorination which forms carcinogenic disinfection by-products.

  13. Ultraviolet air disinfection for protection against influenza

    International Nuclear Information System (INIS)

    Riley, R.L.

    1977-01-01

    Three converging lines of evidence support the belief that it may be possible, under appropriate circumstances, to interrupt the airborne transmission of influenza by ultraviolet (UV) air disinfection. These lines of evidence are: (a) that influenza is airborne; (b) that UV irradiation of the upper air of a room can provide safe and effective disinfection of air in the lower part of the room; and (c) that epidemic spread of airborne viral infections in humans can be prevented if the population under consideration remains in the UV-protected environment

  14. Drinking water contamination and it's disinfection

    International Nuclear Information System (INIS)

    Shah, P.M.J.

    2005-01-01

    High quality water is necessary for the survival of human life. In this paper, an effort has been made to highlight the various causes of water contamination. Some of the most common impurities present in water are pathogenic microorganisms along with organize and in organize pollutants. Different treatment methods are adopted to ensure the potability of water. They include physical, chemical and ultra viable treatment along with solar disinfection etc. The adoption of a particular disinfection strategy depends on the level of treatment required and the resources available to carry out such a treatment. (author)

  15. Inactivation disinfection property of Moringa Oleifera seed extract: optimization and kinetic studies

    Science.gov (United States)

    Idris, M. A.; Jami, M. S.; Hammed, A. M.

    2017-05-01

    This paper presents the statistical optimization study of disinfection inactivation parameters of defatted Moringa oleifera seed extract on Pseudomonas aeruginosa bacterial cells. Three level factorial design was used to estimate the optimum range and the kinetics of the inactivation process was also carried. The inactivation process involved comparing different disinfection models of Chicks-Watson, Collins-Selleck and Homs models. The results from analysis of variance (ANOVA) of the statistical optimization process revealed that only contact time was significant. The optimum disinfection range of the seed extract was 125 mg/L, 30 minutes and 120rpm agitation. At the optimum dose, the inactivation kinetics followed the Collin-Selleck model with coefficient of determination (R2) of 0.6320. This study is the first of its kind in determining the inactivation kinetics of pseudomonas aeruginosa using the defatted seed extract.

  16. Sensitivity to disinfection of bacterial indicator organisms for monitoring the Salmonella Enteritidis status of layer farms after cleaning and disinfection.

    Science.gov (United States)

    Dewaele, I; Ducatelle, R; Herman, L; Heyndrickx, M; De Reu, K

    2011-06-01

    The present study evaluated Escherichia coli, Enterococcus faecalis, and Enterococcus hirae as potential indicator organisms for the possible Salmonella Enteritidis (SE) presence in layer farms after cleaning and disinfection by comparing their susceptibility to disinfection. A quantitative suspension disinfection test according to European Standard EN1656 was performed using disinfection products CID20 and Virocid (both from CID Lines, Ieper, Belgium). In a preliminary test, the sensitivity to both disinfection products was compared between ATCC strains of SE, E. coli, En. faecalis, and En. hirae. The sensitivity of SE to disinfection was most comparable to that of E. coli. A second disinfection test compared the elimination of E. coli to SE ATCC strains as well as field strains. Results showed no significant effect regarding the strain (P > 0.05 for CID20 and Virocid), meaning that no difference was detected in sensitivity toward disinfection. When comparing the sensitivity in general at species level for all concentrations of disinfectant used, no significant difference was found between E. coli and SE in sensitivity to Virocid (P > 0.05). In conclusion, because of its similar response to disinfection in a suspension disinfection test, E. coli could be used as an indicator for possible Salmonella presence after cleaning and disinfection.

  17. Is the pulsed xenon ultraviolet light no-touch disinfection system effective on methicillin-resistant Staphylococcus aureus in the absence of manual cleaning?

    Science.gov (United States)

    Jinadatha, Chetan; Villamaria, Frank C; Restrepo, Marcos I; Ganachari-Mallappa, Nagaraja; Liao, I-Chia; Stock, Eileen M; Copeland, Laurel A; Zeber, John E

    2015-08-01

    Methicillin-resistant Staphylococcus aureus (MRSA) has been shown to survive on ambient surfaces for extended periods of time. Leftover MRSA environmental contamination in a hospital room places future patients at risk. Manual disinfection supplemented by pulsed xenon ultraviolet (PX-UV) light disinfection has been shown to greatly decrease the MRSA bioburden in hospital rooms. However, the effect of PX-UV in the absence of manual disinfection has not been evaluated. Rooms that were previously occupied by a MRSA-positive patient (current colonization or infection) were selected for the study immediately postdischarge. Five high-touch surfaces were sampled, before and after PX-UV disinfection, in each hospital room. The effectiveness of the PX-UV device on the concentration of MRSA was assessed employing a Wilcoxon signed-rank test for all 70 samples with MRSA in 14 rooms, as well as by surface location. The final analysis included 14 rooms. Before PX-UV disinfection there were a total of 393 MRSA colonies isolated from the 5 high-touch surfaces. There were 100 MRSA colonies after disinfection by the PX-UV device and the overall reduction was statistically significant (P disinfection. These findings are important for hospital and environmental services supervisors who plan to adapt new technologies as an adjunct to routine manual disinfection. Published by Elsevier Inc.

  18. Transformation of pharmaceuticals during oxidation/disinfection processes in drinking water treatment.

    Science.gov (United States)

    Postigo, Cristina; Richardson, Susan D

    2014-08-30

    Pharmaceuticals are emerging contaminants of concern and are widespread in the environment. While the levels of these substances in finished drinking waters are generally considered too low for human health concern, there are now concerns about their disinfection by-products (DBPs) that can form during drinking water treatment, which in some cases have been proven to be more toxic than the parent compounds. The present manuscript reviews the transformation products of pharmaceuticals generated in water during different disinfection processes, i.e. chlorination, ozonation, chloramination, chlorine dioxide, UV, and UV/hydrogen peroxide, and the main reaction pathways taking place. Most of the findings considered for this review come from controlled laboratory studies involving reactions of pharmaceuticals with these oxidants used in drinking water treatment. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. A bacteriological study of hospital beds before and after disinfection with phenolic disinfectant

    OpenAIRE

    Denise de Andrade; Emília L. S. Angerami; Carlos Roberto Padovani

    2000-01-01

    In hospitals, one of the ways to control microbial contamination is by disinfecting the furniture used by patients. This study's main objective was to evaluate the microbiological condition of hospital mattresses before and after such disinfection, in order to identify bacteria that are epidemiologically important in nosocomial infection, such as Staphylococcus aureus and Pseudomonas aeruginosa. RODAC plates with two different culture media were used to collect specimens. Patient beds were se...

  20. A bacteriological study of hospital beds before and after disinfection with phenolic disinfectant

    Directory of Open Access Journals (Sweden)

    Andrade Denise de

    2000-01-01

    Full Text Available In hospitals, one of the ways to control microbial contamination is by disinfecting the furniture used by patients. This study's main objective was to evaluate the microbiological condition of hospital mattresses before and after such disinfection, in order to identify bacteria that are epidemiologically important in nosocomial infection, such as Staphylococcus aureus and Pseudomonas aeruginosa. RODAC plates with two different culture media were used to collect specimens. Patient beds were selected according to previously established criteria, and surface areas on the mattresses were chosen at random. From the total of 1 040 plate cultures from 52 mattresses, positive results were obtained from 500 of them (48.1%, 263 before disinfection and 237 after disinfection. Considering the selectivity of the culture media, the positivity rate was high. There were high prevalences of S. aureus both before and after mattress disinfection. The study results suggest that the usual disinfection procedures, instead of diminishing the number of microbes, merely displace them from one part of the mattress to another, and the number of microorganisms remains the same.

  1. A bacteriological study of hospital beds before and after disinfection with phenolic disinfectant

    Directory of Open Access Journals (Sweden)

    Denise de Andrade

    2000-03-01

    Full Text Available In hospitals, one of the ways to control microbial contamination is by disinfecting the furniture used by patients. This study's main objective was to evaluate the microbiological condition of hospital mattresses before and after such disinfection, in order to identify bacteria that are epidemiologically important in nosocomial infection, such as Staphylococcus aureus and Pseudomonas aeruginosa. RODAC plates with two different culture media were used to collect specimens. Patient beds were selected according to previously established criteria, and surface areas on the mattresses were chosen at random. From the total of 1 040 plate cultures from 52 mattresses, positive results were obtained from 500 of them (48.1%, 263 before disinfection and 237 after disinfection. Considering the selectivity of the culture media, the positivity rate was high. There were high prevalences of S. aureus both before and after mattress disinfection. The study results suggest that the usual disinfection procedures, instead of diminishing the number of microbes, merely displace them from one part of the mattress to another, and the number of microorganisms remains the same.

  2. essential oil as hatching egg disinfectant

    African Journals Online (AJOL)

    STORAGESEVER

    2010-04-26

    Apr 26, 2010 ... disinfectant for hatching egg obtained from broiler breeder flock. Oregano essential ... contamination rate, hatchability of fertile egg, body weight at 21 and 42 days, body weight gain and total feed ... successful healthy hatchlings. Several ...... Insecticidal properties of essential plant oils against the mosquito.

  3. STERILIZATION AND DISINFECTION IN A PRIVATE CLINIC

    African Journals Online (AJOL)

    Oral examination is done with a mirror and probe. The mirror is then washed under the tap water and disinfected in 'V3 sterilizing' fluid concentrate. The probe is placed in a tray with ... Protective glasses are worn additionally to the gloves and facemask, when cavity preparation. is being performed. The handpiece is wiped.

  4. USE OF FENTON'S REAGENT AS A DISINFECTANT

    Science.gov (United States)

    Combined sewage samples obtained from a wastewater treatment facility were disinfected by the Fenton's Reagent of several different compositions. The pre-settled samples contained both suspended solids (SS) and dissolved organic carbon (DOC) at concentrations of 28 and 290 mg/L,...

  5. Is pomegranate peels infusion effective for disinfection of toothbrushes?

    Directory of Open Access Journals (Sweden)

    Priscila Lima de Luna FREIRE

    Full Text Available Abstract Introduction Methods of decontamination or sanitization of toothbrushes have been questioned. Objective This study assessed the effectiveness of pomegranate peels infusion as a disinfectant of toothbrushes against Streptococcus mutans. Material and method A sample of 16 schoolchildren aged between 7 and 9 years performed brushing 5 days/week, with a careful brushing once a day. After each day of brushing, the toothbrushes were washed and sprayed with one disinfectant solution. This procedure was repeated for 4 weeks using one of the different solutions per week: distilled water (G1; negative control, pomegranate (Punica granatum Linn peels infusion (G2, 1% sodium hypochlorite (G3 and 0.12% chlorhexidine digluconate (G4. After the fifth day, toothbrushes were collected for laboratory analysis. Toothbrushes heads were subjected to agitation in saline dilution of 10–1, 10–2,10–3, and 25 μL of each dilution were seeded in mitis salivarius agar culture medium for S. mutans colony-forming unit (CFU counting. One calibrated examiner (Kappa = 0.91 performed the CFU (mL–1 × 104 counts. Kruskal-Wallis and Dunn Multiple Comparison tests were used at a significance level of 5%. Result G1 presented the highest number of CFU (3.9 ± 8.4, followed by G2 (3.2 ± 4.0. No S. mutans growth was observed in G3 and G4. There was no statistically significant difference between G1 and G2 and between G3 and G4 (p>0.05. Conclusion Pomegranate infusion was completely ineffective for the disinfection of toothbrushes against S. mutans when compared with 1% sodium hypochlorite and 0.12% chlorhexidine digluconate solutions.

  6. Disinfection of dental impressions - compliance to accepted standards.

    Science.gov (United States)

    Almortadi, N; Chadwick, R G

    2010-12-18

    The responsibility of ensuring impressions have been cleaned and disinfected before dispatch to the dental laboratory lies solely with the dentist. Uncertainty of impression disinfection risks both the health of the receiving dental technician and potential repeat disinfection of an already disinfected impression with detrimental consequences for its dimensions. To ascertain, from the perspectives of dentists and dental technicians, current impression decontamination and disinfection practices with, in the case of the technicians, an estimate of the relative prevalence of contaminated voids within apparently disinfected impressions. Anonymous postal questionnaire. Dentist (n = 200) and dental technician (n = 200) potential participants, selected at random from the registers held by the General Dental Council, were invited to complete an anonymous postal questionnaire that sought to establish current practices and perceived effectiveness of impression disinfection. Questionnaire return rates of 42.1% and 31.2% were recorded for dentists and dental technicians respectively. A wide range of solutions, at different dilutions of the same product, was used by the dentists to disinfect dental impressions. 37.2% rinsed the impressions with water, and 2.6% always brushed debris away, before disinfection. 24.7% of dentists did not inform the laboratory of disinfection. Irrespective of the disinfection status of the received impressions, 50% of the responding dental technicians disinfected all impressions. 95% of them had received blood-contaminated impressions. 15% had encountered blood-filled voids upon trimming back the peripheries of impressions. 64.7% were confident that the impressions received by them had been disinfected by the dentists. Compliance with good practice is less than ideal and education in impression disinfection for both dentists and dental technicians is required to address this.

  7. Antimicrobial effect of three disinfecting agents on Resilon cones and their effect on surface topography: An in vitro study.

    Science.gov (United States)

    Chandrappa, Mahesh Martur; Meharwade, Prasanna Mahadevasa; Srinivasan, Raghu; Bhandary, Shreetha; Nasreen, Farhat

    2016-01-01

    The objective of this study was to evaluate the effectiveness of 5.25% sodium hypochlorite (NaOCl), 2% chlorhexidine (CHX), and 2% peracetic acid (PAA) in disinfecting Resilon cones and to evaluate topographical changes microscopically under scanning electron microscope (SEM) after rapid chemical disinfection. Resilon cones were disinfected in an ultraviolet (UV) light chamber for 20 min and contaminated by immersing in a microbial suspension of Enterococcus faecalis for 30 min. The contaminated cones were then immersed in the 5.25% NaOCl, 2% CHX, and 2% PAA for 1 min, 5 min, and 10 min, separately. The cones were then incubated at 37°C in thioglycollate broth for 7 days and examined for turbidity. The samples showing turbidity were subcultured on blood agar and incubated at 37°C for 48 h. Gram staining was done to confirm that the cultured bacteria were E. faecalis. Surface changes of disinfected Resilon cones were evaluated under SEM. The data were analyzed statistically using Kruskal-Wallis, analysis of variance (ANOVA), and Mann-Whitney U-test. In eliminating E. faecalis, 5.25% NaOCl was most effective followed by 2% PAA and 2% CHX. Topographic examination of tested Resilon cones revealed some surface deposits after disinfection with 5.25% NaOCl and 2% CHX, whereas 2% PAA caused surface erosion. In disinfecting Resilon cones, 5.25% NaOCl is most effective followed by 2% PAA and 2% CHX.

  8. Fingerprinting of egg and oil binders in painted artworks by matrix-assisted laser desorption ionization time-of-flight mass spectrometry analysis of lipid oxidation by-products.

    Science.gov (United States)

    Calvano, C D; van der Werf, I D; Palmisano, F; Sabbatini, L

    2011-06-01

    A matrix-assisted laser desorption ionization time-of-flight mass spectrometry-based approach was applied for the detection of various lipid classes, such as triacylglycerols (TAGs) and phospholipids (PLs), and their oxidation by-products in extracts of small (50-100 μg) samples obtained from painted artworks. Ageing of test specimens under various conditions, including the presence of different pigments, was preliminarily investigated. During ageing, the TAGs and PLs content decreased, whereas the amount of diglycerides, short-chain oxidative products arising from TAGs and PLs, and oxidized TAGs and PLs components increased. The examination of a series of model paint samples gave a clear indication that specific ions produced by oxidative cleavage of PLs and/or TAGs may be used as markers for egg and drying oil-based binders. Their elemental composition and hypothetical structure are also tentatively proposed. Moreover, the simultaneous presence of egg and oil binders can be easily and unambiguously ascertained through the simultaneous occurrence of the relevant specific markers. The potential of the proposed approach was demonstrated for the first time by the analysis of real samples from a polyptych of Bartolomeo Vivarini (fifteenth century) and a "French school" canvas painting (seventeenth century).

  9. Comparative study with two different enrichments in the culture media used in the disinfectant efficacy assay.

    Science.gov (United States)

    Sabagh, Bruna Peres; Souto, Aline da Silva Soares; Reis, Louise Moreira; Silva, Sérgio Alves da; Pereira, Daniella Cristina Rodrigues; Neves, Marta de Campos; Pinheiro, Rodrigo Rollin; Duarte, Rafael Silva; Miyazaki, Neide Hiromi Tokumaru; Bôas, Maria Helena Simões Villas

    2012-02-01

    Recent changes in Brazilian legislation for commercial disinfectants have been published due to the recent epidemic of nosocomial infections caused by rapidly growing mycobacteria (RGM) in many states of Brazil over the last 8years. One of these documents requires that all the manufacturers provide evidence of efficacy of sterilizing and disinfectant products, used for semi critical medical devices, against the Mycobacterium bovis BCG Moreau and Mycobacterium abscessus subsp. bolletii INCQS 00594 strains by using the Confirmative in vitro Test for Determining Tuberculocidal Activity of Disinfectants recommended by the Association of Official Analytical Chemists. These changes have caused additional costs and increased problems for importation of enrichment products at national laboratories where disinfectant efficacy assay service is performed. Middlebrook ADC Enrichment (ADC) is provided by a unique manufacturer and used in the official protocol. The aim of the present study was to evaluate an alternative in house low-cost enrichment composed of fetal bovine serum and glucose (FBSG) with ADC for performance of disinfectant efficacy assay against mycobacteria. After obtaining the growth curves for M. abscessus ATCC 19977, M. abscessus subsp. bolletii INCQS 00594, Mycobacterium chelonae ATCC 35752, and Mycobacterium fortuitum ATCC 6841 by using ADC enrichment and FBSG in Kirchners and 7H9 culture media. Through statistical analysis via the Kruskal-Wallis test on the evaluation of microorganism growth rate, it was observed that there was no inhibition of RGM growth by any of the enrichments used. These results suggest that low-cost enrichment FBSG may be used as a potential substitute of ADC for composition of media for mycobacterial growth, including in disinfectant tests. Copyright © 2011 Elsevier B.V. All rights reserved.

  10. Evaluation of the hygienogram scores and related data obtained after cleaning and disinfection of poultry houses in Flanders during the period 2007 to 2014.

    Science.gov (United States)

    Maertens, H; De Reu, K; Van Weyenberg, S; Van Coillie, E; Meyer, E; Van Meirhaeghe, H; Van Immerseel, F; Vandenbroucke, V; Vanrobaeys, M; Dewulf, J

    2018-02-01

    Cleaning and disinfection (C&D) of poultry houses is an essential aspect in farm hygiene management. Adequate performance of the different steps of a C&D protocol and the use of suitable products are key to prevent and control zoonoses and animal diseases. Hygiene monitoring on total aerobic flora through sampling with agar contact plates at different locations of the poultry house results in a hygienogram score that is used to evaluate the proper execution of C&D.This study analyzed the hygienogram scores of 19,739 poultry flocks in Flanders after C&D. Data relating to the C&D protocol, i.e., year, season, husbandry system, production type, cleaning product, sampler, active components of the disinfectant, disinfection time, disinfection temperature, and disinfection responsible, were collected.The average hygienogram score decreased significantly over time, suggesting a general improvement between 2007 and 2014. Differences in scores were found among the husbandry systems, with the barn/aviary system having a significantly better hygienogram score compared to the floor house, furnished cage, and battery. Significantly better scores also were found when a cleaning product was used in the C&D protocol. Disinfection with a peracetic acid and hydrogen peroxide combination or formaldehyde gave the best scores. In addition, C&D protocols using ≥2 different disinfectants showed improved results compared to the use of one single disinfectant. Finally, disinfection applied by a specialist contractor resulted in a better score compared to disinfection by the farmer.In conclusion, analysis of the hygienogram scores and related data allowed identifying several factors, resulting in an improvement, which may reduce the total bacterial load in poultry stables and, consequently, the number of zoonotic and pathogenic micro-organisms. © 2017 Poultry Science Association Inc.

  11. Peracetic Acid as a Green Disinfectant for Combined Sewer ...

    Science.gov (United States)

    This cooperative research and development agreement between U.S. EPA, Solvay, MSDGC, and CB&I is evaluating the potential of PAA for disinfection of Muddy Creek CSO wastewater and comparing that with sodium hypochlorite disinfection. This presentation will document the effectiveness of sodium hypochlorite and PAA for the inactivation of E. coli in CSO wastewater using laboratory bench-scale jar tests and Muddy Creek field site studies based on the following items:•Storage, shelf life, and application of the disinfectants.•Effectiveness of the disinfectants in the inactivation of E. coli.•Formation of harmful byproducts by the disinfectants.•Operation and maintenance costs, including the cost of the disinfectant, its storage, application, and neutralizing agent for the disinfectant to maintain the Ohio EPA guideline for residual disinfectant at the discharge point. Like many cities in the USA, Cincinnati, Ohio is attempting to find the best way to meet state and federal requirements concerning combined sewer overflow (CSO) wastewater. The Muddy Creek CSO treatment facility was constructed to provide treatment for CSO Numbers 198 and 216 from the Westwood Trunk sewer. The Metropolitan Sewer District of Greater Cincinnati (MSDGC) is currently using sodium hypochlorite for disinfection in this treatment facility. Because of degradation of hypochlorite during storage and the formation of chlorinated disinfection byproducts (DBPs), MSDGC is evaluating alternat

  12. Peracetic acid for secondary effluent disinfection: a comprehensive performance assessment.

    Science.gov (United States)

    Antonelli, M; Turolla, A; Mezzanotte, V; Nurizzo, C

    2013-01-01

    The paper is a review of previous research on secondary effluent disinfection by peracetic acid (PAA) integrated with new data about the effect of a preliminary flash-mixing step. The process was studied at bench and pilot scale to assess its performance for discharge in surface water and agricultural reuse (target microorganisms: Escherichia coli and faecal coliform bacteria). The purposes of the research were: (1) determining PAA decay and disinfection kinetics as a function of operating parameters, (2) evaluating PAA suitability as a disinfectant, (3) assessing long-term disinfection efficiency, (4) investigating disinfected effluent biological toxicity on some aquatic indicator organisms (Vibrio fischeri, Daphnia magna and Selenastrum capricornutum), (5) comparing PAA with conventional disinfectants (sodium hypochlorite, UV irradiation). PAA disinfection was capable of complying with Italian regulations on reuse (10 CFU/100 mL for E. coli) and was competitive with benchmarks. No regrowth phenomena were observed, as long as needed for agricultural reuse (29 h after disinfection), even at negligible concentrations of residual disinfectant. The toxic effect of PAA on the aquatic environment was due to the residual disinfectant in the water, rather than to chemical modification of the effluent.

  13. Dynamics of cholera epidemics with impulsive vaccination and disinfection.

    Science.gov (United States)

    Sisodiya, Omprakash Singh; Misra, O P; Dhar, Joydip

    2018-04-01

    Waterborne diseases have a tremendous influence on human life. The contaminated drinking water causes water-borne disease like cholera. Pulse vaccination is an important and effective strategy for the elimination of infectious diseases. A waterborne disease like cholera can also be controlled by using impulse technique. In this paper, we have proposed a delayed SEIRB epidemic model with impulsive vaccination and disinfection. We have studied the pulse vaccination strategy and sanitation to control the cholera disease. The existence and stability of the disease-free and endemic periodic solution are investigated both analytically and numerically. It is shown that there exists an infection-free periodic solution, using the impulsive dynamical system defined by the stroboscopic map. It is observed that the infection-free periodic solution is globally attractive when the impulse period is less than some critical value. From the analysis of the model, we have obtained a sufficient condition for the permanence of the epidemic with pulse vaccination. The main highlight of this paper is to introduce impulse technique along with latent period into the SEIRB epidemic model to investigate the role of pulse vaccination and disinfection on the dynamics of the cholera epidemics. Copyright © 2018 Elsevier Inc. All rights reserved.

  14. Transformation of pharmaceuticals during oxidation/disinfection processes in drinking water treatment

    International Nuclear Information System (INIS)

    Postigo, Cristina; Richardson, Susan D.

    2014-01-01

    Graphical abstract: - Highlights: • Review of transformation pathways of pharmaceuticals during disinfection processes. • DBPs are formed with chlorine, chloramine, ozone, chlorine dioxide, UV, or UV/H 2 O 2 . • Chlorine reacts with amine and reduced sulfur groups and activated aromatic systems. • Chlorine dioxide and ozone react with electron-rich functional groups. • Potential health effects are noted for some pharmacuetical DBPs when available. - Abstract: Pharmaceuticals are emerging contaminants of concern and are widespread in the environment. While the levels of these substances in finished drinking waters are generally considered too low for human health concern, there are now concerns about their disinfection by-products (DBPs) that can form during drinking water treatment, which in some cases have been proven to be more toxic than the parent compounds. The present manuscript reviews the transformation products of pharmaceuticals generated in water during different disinfection processes, i.e. chlorination, ozonation, chloramination, chlorine dioxide, UV, and UV/hydrogen peroxide, and the main reaction pathways taking place. Most of the findings considered for this review come from controlled laboratory studies involving reactions of pharmaceuticals with these oxidants used in drinking water treatment

  15. Transformation of pharmaceuticals during oxidation/disinfection processes in drinking water treatment

    Energy Technology Data Exchange (ETDEWEB)

    Postigo, Cristina [Institute for Environmental Assessment and Water Research (IDAEA)—Spanish National Research Council (CID-CSIC), Barcelona (Spain); Richardson, Susan D., E-mail: richardson.susan@sc.edu [Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC (United States)

    2014-08-30

    Graphical abstract: - Highlights: • Review of transformation pathways of pharmaceuticals during disinfection processes. • DBPs are formed with chlorine, chloramine, ozone, chlorine dioxide, UV, or UV/H{sub 2}O{sub 2}. • Chlorine reacts with amine and reduced sulfur groups and activated aromatic systems. • Chlorine dioxide and ozone react with electron-rich functional groups. • Potential health effects are noted for some pharmacuetical DBPs when available. - Abstract: Pharmaceuticals are emerging contaminants of concern and are widespread in the environment. While the levels of these substances in finished drinking waters are generally considered too low for human health concern, there are now concerns about their disinfection by-products (DBPs) that can form during drinking water treatment, which in some cases have been proven to be more toxic than the parent compounds. The present manuscript reviews the transformation products of pharmaceuticals generated in water during different disinfection processes, i.e. chlorination, ozonation, chloramination, chlorine dioxide, UV, and UV/hydrogen peroxide, and the main reaction pathways taking place. Most of the findings considered for this review come from controlled laboratory studies involving reactions of pharmaceuticals with these oxidants used in drinking water treatment.

  16. Understanding the antimicrobial activity of selected disinfectants against methicillin-resistant Staphylococcus aureus (MRSA.

    Directory of Open Access Journals (Sweden)

    Ebrahim Aboualizadeh

    Full Text Available Disinfectants and biocidal products have been widely used to combat Methicillin-resistant Staphylococcus aureus (MRSA infections in homes and healthcare environments. Although disruption of cytoplasmic membrane integrity has been documented as the main bactericidal effect of biocides, little is known about the biochemical alterations induced by these chemical agents. In this study, we used Fourier transform infrared (FT-IR spectroscopy and chemometric tools as an alternative non-destructive technique to determine the bactericidal effects of commonly used disinfectants against MRSA USA-300. FTIR spectroscopy permits a detailed characterization of bacterial reactivity, allowing an understanding of the fundamental mechanism of action involved in the interaction between bacteria and disinfectants. The disinfectants studied were ethanol 70% (N = 5, isopropanol (N = 5, sodium hypochlorite (N = 5, triclosan (N = 5 and triclocarban (N = 5. Results showed less than 5% colony forming units growth of MRSA treated with triclocarban and no growth in the other groups. Nearly 70,000 mid-infrared spectra from the five treatments and the two control (untreated; N = 4 groups of MRSA (bacteria grown in TSB and incubated at 37°C (Control I / at ambient temperature (Control II, for 24h were pre-processed and analyzed using principal component analysis followed by linear discriminant analysis (PCA-LDA. Clustering of strains of MRSA belonging to five treatments and the discrimination between each treatment and two control groups in MRSA (untreated were investigated. PCA-LDA discriminatory frequencies suggested that ethanol-treated spectra are the most similar to isopropanol-treated spectra biochemically. Also reported here are the biochemical alterations in the structure of proteins, lipid membranes, and phosphate groups of MRSA produced by sodium hypochlorite, triclosan, and triclocarban treatments. These findings provide mechanistic information involved in the

  17. Understanding the antimicrobial activity of selected disinfectants against methicillin-resistant Staphylococcus aureus (MRSA).

    Science.gov (United States)

    Aboualizadeh, Ebrahim; Bumah, Violet V; Masson-Meyers, Daniela S; Eells, Janis T; Hirschmugl, Carol J; Enwemeka, Chukuka S

    2017-01-01

    Disinfectants and biocidal products have been widely used to combat Methicillin-resistant Staphylococcus aureus (MRSA) infections in homes and healthcare environments. Although disruption of cytoplasmic membrane integrity has been documented as the main bactericidal effect of biocides, little is known about the biochemical alterations induced by these chemical agents. In this study, we used Fourier transform infrared (FT-IR) spectroscopy and chemometric tools as an alternative non-destructive technique to determine the bactericidal effects of commonly used disinfectants against MRSA USA-300. FTIR spectroscopy permits a detailed characterization of bacterial reactivity, allowing an understanding of the fundamental mechanism of action involved in the interaction between bacteria and disinfectants. The disinfectants studied were ethanol 70% (N = 5), isopropanol (N = 5), sodium hypochlorite (N = 5), triclosan (N = 5) and triclocarban (N = 5). Results showed less than 5% colony forming units growth of MRSA treated with triclocarban and no growth in the other groups. Nearly 70,000 mid-infrared spectra from the five treatments and the two control (untreated; N = 4) groups of MRSA (bacteria grown in TSB and incubated at 37°C (Control I) / at ambient temperature (Control II), for 24h) were pre-processed and analyzed using principal component analysis followed by linear discriminant analysis (PCA-LDA). Clustering of strains of MRSA belonging to five treatments and the discrimination between each treatment and two control groups in MRSA (untreated) were investigated. PCA-LDA discriminatory frequencies suggested that ethanol-treated spectra are the most similar to isopropanol-treated spectra biochemically. Also reported here are the biochemical alterations in the structure of proteins, lipid membranes, and phosphate groups of MRSA produced by sodium hypochlorite, triclosan, and triclocarban treatments. These findings provide mechanistic information involved in the interaction

  18. [Control of disinfection in buildings used for poultry raising].

    Science.gov (United States)

    Maris, P

    1989-01-01

    During a 2-year survey in turkey breeding farms, it was possible to compare six disinfection procedures by monitoring 14 first disinfections following the breeding house cleaning and 14 second disinfections prior to animal return. By swabbing all the germs from asbestos concrete surfaces, we noted that in the case of first disinfection the chloramine T-based product was more effective than phenol or quaternary ammonium-aldehyde-based products. For the second disinfection, it was demonstrated that a minimal dose of 15 kg of formaldehyde was necessary for disinfection to be satisfactory; 12 to 15 kg paraformaldehyde was as effective as 40 to 60 liters of 30-35% formol for buildings, the ground surface of which covered between 1,000 and 1,300 m2.

  19. Application and study of conjunctival sac disinfectants in ophthalmic surgeries

    Directory of Open Access Journals (Sweden)

    Yan-Fei Luo

    2016-01-01

    Full Text Available Postoperative endophthalmitis is the most serious complications of ophthalmic surgeries. Conjunctival sac disinfection is currently recognized as an effectively important way to reduce the risk of endophthalmitis. At present, there are some disinfectants has been used in clinic or in the researches:mercury agent, gentamicin, povidone iodine and acid electrolytic water. All kinds of disinfectants play the role of disinfection by different ways. Povidone iodine is the most widely used conjunctival sac disinfectant. Mercurial and gentamicin have been rarely used because they pollute the environment, are easy to cause drug resistant bacteria, localized side reactions and so on. The acid electrolyte water is not used in clinic at present. With the popularization and development of the ophthalmic surgeries, the ophthalmologists have become more and more concerned about the postoperative eye comfort, the research and application of conjunctival sac disinfectant in the future will continue to be updated and developed.

  20. Is free halogen necessary for disinfection?

    Science.gov (United States)

    Williams, D E; Elder, E D; Worley, S D

    1988-10-01

    The principle of Le Chatelier was used in demonstrating that 3-chloro-4,4-dimethyl-2-oxazolidinone (compound 1) itself kills Staphylococcus aureus rather than the very small amount of free chlorine in hydrolysis equilibrium with compound 1. On the other hand, when the N-bromo analog of compound 1 (compound 1B) was used as the disinfectant, the mixture of combined compound 1B and free bromine formed in the hydrolysis equilibrium provided disinfection. When the hydrolysis equilibrium for 1B was suppressed to the level at which a negligible amount of free bromine remained in solution, combined compound 1B was much more efficacious than combined compound 1 at killing S. aureus.

  1. Ultraviolet light - nature's own disinfection process

    Energy Technology Data Exchange (ETDEWEB)

    Munkeberg, T [Thorolf Gregersen a/s, Oslo (Norway)

    1978-05-18

    Ultraviolet radiation from the sun is the means by which natural pollution products, as well as much of the smaller amount of pollution products produced by man, are converted and returned to the cycle of nature. Artificial ultraviolet radiation offers an optimum method for the disinfection of drinking water and can be used in the long term without undesireable effects on man or the enviromment. There is no evidence that ultraviolet irradiation leads to radiation resistant mutations of bacteria. The geometrical arrangement of ultraviolet disinfection units is described and the capacities of typical units is mentioned as being 600-800 m/sup 3/ /hr, though there is no reason why this should not be increased.

  2. Ultraviolet light - nature's own disinfection process

    International Nuclear Information System (INIS)

    Munkeberg, T.

    1978-01-01

    Ultraviolet radiation from the sun is the means by which natural pollution products, as well as much of the smaller amount of pollution products produced by man, are converted and returned to the cycle of nature. Artificial ultraviolet radiation offers an optimum method for the disinfection of drinking water and can be used in the long term without undesireable effects on man or the enviromment. There is no evidence that ultraviolet irradiation leads to radiation resistant mutations of bacteria. The geometrical arrangement of ultraviolet disinfection units is described and the capacities of typical units is mentioned as being 600-800 m 3 /hr, though there is no reason why this should not be increased. (JIW)

  3. Assessment of photoreactivation following ultraviolet light disinfection

    International Nuclear Information System (INIS)

    Kashimada, K.; Kamiko, N.; Yamamoto, K.; Ohgaki, S.

    1996-01-01

    Photoreactivation of microorganisms following UV disinfection is one of the research topics of interest in assessing the performance of UV disinfection, because there is little consensus on how the visible light intensity relates to the photoreactivation rate and the maximum survival in wastewater treatment processes. Apparent photoreactivation by a fluorescent lamp was observed in case of indicator bacteria (heterotrophic bacteria, coliform bacteria, fecal coliforms) in raw sewage, but not E. coli B and E. coli K12 A/λ(F+). Inactivation of fecal coliform was observed simultaneously during photoreactivation process by sunlight. Dose rate at 360 nm wave length as visible light intensity showed that it was a useful indicator for assessing the photoreactivation rate and the maximum survival when photoreactivation took place by both fluorescent lamp and sunlight. The model for photoreactivation was developed. The photoreactivation rate increased with increasing visible light intensity at 360 nm. However, the maximum survival value may not be affected by visible light intensity. (author)

  4. UV DISINFECTION GUIDANCE MANUAL FOR THE ...

    Science.gov (United States)

    Provides technical information on selection, design and operation of UV systems; provides regulatory agencies with guidance and the necessary tools to assess UV systems at the design, start-up, and routine operation phase; provides manufacturers with the testing and performance standards for UV components and systems for treating drinking water. Provide guidance to water systems, regulators and manufacturers on UV disinfection of drinking water.

  5. Nationwide Study of Humidifier Disinfectant Lung Injury in South Korea, 1994-2011. Incidence and Dose-Response Relationships.

    Science.gov (United States)

    Paek, Domyung; Koh, Younsuck; Park, Dong-Uk; Cheong, Hae-Kwan; Do, Kyung-Hyun; Lim, Chae-Man; Hong, Soo-Jong; Kim, Yong-Hwa; Leem, Jong-Han; Chung, Kyu Hyuck; Choi, Ye-Yong; Lee, Jong-Hyeon; Lim, Sin-Ye; Chung, Eun-Hee; Cho, Young Ah; Chae, Eun Jin; Joh, Joon-Sung; Yoon, Yup; Lee, Kyu-Hong; Choi, Bo Youl; Gwack, Jin

    2015-12-01

    Humidifier disinfectant lung injury is an acute lung disease attributed to recurrent inhalation of certain disinfectant aerosols emitted from room humidifiers. An outbreak of this toxic lung injury occurred in South Korea from 1995 until all humidifier disinfectant products were recalled from the consumer market by the government in 2011. A nationwide study was conducted to ascertain and classify all potential cases of humidifier disinfectant lung injury in Korea and to assess dose-response relationships. By several mechanisms, clinicians and the general public were invited to report all suspected cases of humidifier disinfectant lung injury to public health officials in South Korea. A committee was convened to define diagnostic criteria based on pathologic, radiologic, and clinical findings for index cases, combined with assessment of environmental exposure to humidifier disinfectants. Clinical review and environmental assessments were performed and later combined to determine overall likelihood of disease for each study participant, classified as definite, probable, possible, or unlikely. Survival time from exposure to onset of symptoms was analyzed to assess dose-response relationships. Three broad categories of risk factors were examined: (1) biological susceptibility, (2) temporal cycle of exposure and recovery, and (3) spatial conditions and density of disinfectant. Of 374 possible cases identified and reviewed, 329 were unanimously classified by the diagnostic committee, as follows: 117 definite, 34 probable, 38 possible and 140 unlikely cases. A total of 62 individuals with definite or probable disease died. Risk factors examined for polyhexamethyleneguanidine phosphate exposure that were found to be significant in shortening survival included age 4 years or younger at onset, use of disinfectant for 7 days per week, airborne density of 800 μg/m(3) or more of disinfectant, and daily exposure 11 or more hours in duration. Dose-response analysis indicated

  6. Role of disinfection in the Infection Prevention Multibarrier System

    OpenAIRE

    Kramer, Axel

    2007-01-01

    The role of disinfection in infection prevention has been analyzed over the past 50 years both in the form of benefit-risk evaluations as well as in an epidemiological sense. This has served as the basis for not only national and international guidelines and recommendations, but has also created the legal and normative framework for regulation of infection control (and hence of disinfection) in numerous and acts and ordinances. Likewise, today the efficacy of disinfection measures, user safet...

  7. Disinfectant effect of Methylated Ethanol against Listeria species

    OpenAIRE

    Y Yakubu; M D Salihu; O O Faleke; M B Abubakar; A A Magaji,A U Junaidu

    2012-01-01

    This study was carried out in order to determine the disinfectant effect of Methylated spirit® (95% methanol and 5% ethanol) as a teat dip against Listeria species. Hand milking was employed to collect 576 (288 x 2) raw milk samples from different lactating cows within Sokoto metropolis (Nigeria). 288 samples were collected before disinfecting the udder teats with Methylated spirit®, while the other 288 were collected after disinfection with Methylated spirit®. The ...

  8. Efficacy of a variety of disinfectants against Listeria spp.

    OpenAIRE

    Best, M; Kennedy, M E; Coates, F

    1990-01-01

    The efficacy of 14 disinfectants against Listeria innocua and two strains of Listeria monocytogenes in the presence of organic matter was studied. Quantitative efficacy tests were used. Many of the disinfectants tested were not as effective on Listeria spp. when the test organisms were dried onto the surface of steel disks (carrier tests) as they were when the organisms were placed in suspension (suspension test). The presence of whole serum and milk (2% fat) further reduced the disinfectant ...

  9. Bacterial Spores Survive Treatment with Commercial Sterilants and Disinfectants

    OpenAIRE

    Sagripanti, Jose-Luis; Bonifacino, Aylin

    1999-01-01

    This study compared the activity of commercial liquid sterilants and disinfectants on Bacillus subtilis spores deposited on three types of devices made of noncorrodible, corrodible, or polymeric material. Products like Renalin, Exspor, Wavicide-01, Cidexplus, and cupric ascorbate were tested under conditions specified for liquid sterilization. These products, at the shorter times indicated for disinfection, and popular disinfectants, like Clorox, Cavicide, and Lysol were also studied. Data ob...

  10. Development of the electrical discharge method for water disinfection

    International Nuclear Information System (INIS)

    Vojtenko, L.M.; Kononov, O.V.; Starchik, P.D.; Samojlenko, L.S.; Stavs'ka, S.S.

    1995-01-01

    Studies of processes of bacterially polluted water disinfection by the method of pulse electrical discharge in water are presented. The studies was performed to improve the disinfection technology. Main attention was concentrated to clear up effect of discharge instability on the disinfection. An influence of the shape and sizes of electrodes on repeatability of discharges was also investigated. It was found that salts solved in water greatly influence ultraviolet radiation absorption coefficients

  11. Anaerobic digestion of slaughterhouse by-products

    DEFF Research Database (Denmark)

    Hejnfelt, Anette; Angelidaki, Irini

    2009-01-01

    Anaerobic digestion of animal by-products was investigated in batch and semi-continuously fed, reactor experiments at 55 degrees C and for some experiments also at 37 degrees C. Separate or mixed by-products from pigs were tested. The methane potential measured by batch assays for meat- and bone...... flour, fat, blood, hair, meat, ribs, raw waste were: 225, 497,487, 561, 582, 575, 359, 619 dm(3) kg(-1) respectively, corresponding to 50-100% of the calculated theoretical methane potential. Dilution of the by-products had a positive effect on the specific methane yield with the highest dilutions...... giving the best results. High concentrations of long-chain fatty acids and ammonia in the by-products were found to inhibit the biogas process at concentrations higher than 5 g lipids dm(-3) and 7 gN dm(-3) respectively. Pretreatment (pasteurization: 70 degrees C, sterilization: 133 degrees C, and alkali...

  12. Spiral-shaped reactor for water disinfection

    KAUST Repository

    Soukane, Sofiane

    2016-04-20

    Chlorine-based processes are still widely used for water disinfection. The disinfection process for municipal water consumption is usually carried out in large tanks, specifically designed to verify several hydraulic and disinfection criteria. The hydrodynamic behavior of contact tanks of different shapes, each with an approximate total volume of 50,000 m3, was analyzed by solving turbulent momentum transport equations with a computational fluid dynamics code, namely ANSYS fluent. Numerical experiments of a tracer pulse were performed for each design to generate flow through curves and investigate species residence time distribution for different inlet flow rates, ranging from 3 to 12 m3 s−1. A new nature-inspired Conch tank design whose shape follows an Archimedean spiral was then developed. The spiral design is shown to strongly outperform the other tanks’ designs for all the selected plug flow criteria with an enhancement in efficiency, less short circuiting, and an order of magnitude improvement in mixing and dispersion. Moreover, following the intensification philosophy, after 50% reduction in its size, the new design retains its properties and still gives far better results than the classical shapes.

  13. Evaluation of toothbrush disinfection via different methods

    Directory of Open Access Journals (Sweden)

    Adil BASMAN

    2016-01-01

    Full Text Available The aim of this study was to compare the efficacy of using a dishwasher or different chemical agents, including 0.12% chlorhexidine gluconate, 2% sodium hypochlorite (NaOCl, a mouthrinse containing essential oils and alcohol, and 50% white vinegar, for toothbrush disinfection. Sixty volunteers were divided into five experimental groups and one control group (n = 10. Participants brushed their teeth using toothbrushes with standard bristles, and they disinfected the toothbrushes according to instructed methods. Bacterial contamination of the toothbrushes was compared between the experimental groups and the control group. Data were analyzed by Kruskal–Wallis and Duncan's multiple range tests, with 95% confidence intervals for multiple comparisons. Bacterial contamination of toothbrushes from individuals in the experimental groups differed from those in the control group (p < 0.05. The most effective method for elimination of all tested bacterial species was 50% white vinegar, followed in order by 2% NaOCl, mouthrinse containing essential oils and alcohol, 0.12% chlorhexidine gluconate, dishwasher use, and tap water (control. The results of this study show that the most effective method for disinfecting toothbrushes was submersion in 50% white vinegar, which is cost-effective, easy to access, and appropriate for household use.

  14. Impact of UV and peracetic acid disinfection on the prevalence of virulence and antimicrobial resistance genes in uropathogenic Escherichia coli in wastewater effluents.

    Science.gov (United States)

    Biswal, Basanta Kumar; Khairallah, Ramzi; Bibi, Kareem; Mazza, Alberto; Gehr, Ronald; Masson, Luke; Frigon, Dominic

    2014-06-01

    Wastewater discharges may increase the populations of pathogens, including Escherichia coli, and of antimicrobial-resistant strains in receiving waters. This study investigated the impact of UV and peracetic acid (PAA) disinfection on the prevalence of virulence and antimicrobial resistance genes in uropathogenic Escherichia coli (UPEC), the most abundant E. coli pathotype in municipal wastewaters. Laboratory disinfection experiments were conducted on wastewater treated by physicochemical, activated sludge, or biofiltration processes; 1,766 E. coli isolates were obtained for the evaluation. The target disinfection level was 200 CFU/100 ml, resulting in UV and PAA doses of 7 to 30 mJ/cm(2) and 0.9 to 2.0 mg/liter, respectively. The proportions of UPECs were reduced in all samples after disinfection, with an average reduction by UV of 55% (range, 22% to 80%) and by PAA of 52% (range, 11% to 100%). Analysis of urovirulence genes revealed that the decline in the UPEC populations was not associated with any particular virulence factor. A positive association was found between the occurrence of urovirulence and antimicrobial resistance genes (ARGs). However, the changes in the prevalence of ARGs in potential UPECs were different following disinfection, i.e., UV appears to have had no effect, while PAA significantly reduced the ARG levels. Thus, this study showed that both UV and PAA disinfections reduced the proportion of UPECs and that PAA disinfection also reduced the proportion of antimicrobial resistance gene-carrying UPEC pathotypes in municipal wastewaters.

  15. Impact of UV and Peracetic Acid Disinfection on the Prevalence of Virulence and Antimicrobial Resistance Genes in Uropathogenic Escherichia coli in Wastewater Effluents

    Science.gov (United States)

    Biswal, Basanta Kumar; Khairallah, Ramzi; Bibi, Kareem; Mazza, Alberto; Gehr, Ronald; Masson, Luke

    2014-01-01

    Wastewater discharges may increase the populations of pathogens, including Escherichia coli, and of antimicrobial-resistant strains in receiving waters. This study investigated the impact of UV and peracetic acid (PAA) disinfection on the prevalence of virulence and antimicrobial resistance genes in uropathogenic Escherichia coli (UPEC), the most abundant E. coli pathotype in municipal wastewaters. Laboratory disinfection experiments were conducted on wastewater treated by physicochemical, activated sludge, or biofiltration processes; 1,766 E. coli isolates were obtained for the evaluation. The target disinfection level was 200 CFU/100 ml, resulting in UV and PAA doses of 7 to 30 mJ/cm2 and 0.9 to 2.0 mg/liter, respectively. The proportions of UPECs were reduced in all samples after disinfection, with an average reduction by UV of 55% (range, 22% to 80%) and by PAA of 52% (range, 11% to 100%). Analysis of urovirulence genes revealed that the decline in the UPEC populations was not associated with any particular virulence factor. A positive association was found between the occurrence of urovirulence and antimicrobial resistance genes (ARGs). However, the changes in the prevalence of ARGs in potential UPECs were different following disinfection, i.e., UV appears to have had no effect, while PAA significantly reduced the ARG levels. Thus, this study showed that both UV and PAA disinfections reduced the proportion of UPECs and that PAA disinfection also reduced the proportion of antimicrobial resistance gene-carrying UPEC pathotypes in municipal wastewaters. PMID:24727265

  16. Antimicrobial activity of disinfectant agents incorporated into type IV dental stone.

    Science.gov (United States)

    Pereira, Rodrigo de Paula; Lucas, Matheus Guilherme; Spolidorio, Denise Madalena Palomari; Arioli Filho, João Neudenir

    2012-06-01

    This study evaluated the antimicrobial activity of two disinfectant agents, 2% chlorhexidine digluconate solution (CHX) and 98% chlorhexidine hydrochloride powder (HYD), incorporated into type IV dental stone at the time of mixing. Agar diffusion test was used for the following microorganisms: Escherichia coli, Staphylococcus aureus, Bacillus subtilis and Candida albicans. The specimens were grouped in: (1) dental stone mixed with sterile distilled water; (2) paper disc soaked with CHX; (3) dental stone mixed with CHX; and (4) dental stone with incorporation of HYD, in 1% proportion of the dental stone mass and mixed with sterile distilled water. The culture medium was inoculated with microbial suspensions 1 and 24 h after pouring of the dental stone. The antimicrobial activity was evaluated by the average diameter of microbial growth inhibition zones. The data were analysed with a nested anova (p < 0.05) and Tukey test for specific comparisons. The disinfectant agents demonstrated antimicrobial activity against all microorganisms, with the exception of C. albicans, against which the CHX was ineffective in two periods of analysis. Significant differences between disinfectants were found with all microorganisms. The disinfectant agents analysed were effective against most of the microorganisms tested, except C. albicans. © 2011 The Gerodontology Society and John Wiley & Sons A/S.

  17. Bacterial spores survive treatment with commercial sterilants and disinfectants.

    Science.gov (United States)

    Sagripanti, J L; Bonifacino, A

    1999-09-01

    This study compared the activity of commercial liquid sterilants and disinfectants on Bacillus subtilis spores deposited on three types of devices made of noncorrodible, corrodible, or polymeric material. Products like Renalin, Exspor, Wavicide-01, Cidexplus, and cupric ascorbate were tested under conditions specified for liquid sterilization. These products, at the shorter times indicated for disinfection, and popular disinfectants, like Clorox, Cavicide, and Lysol were also studied. Data obtained with a sensitive and quantitative test suggest that commercial liquid sterilants and disinfectants are less effective on contaminated surfaces than generally acknowledged.

  18. Safety and durability of low-density polyethylene bags in solar water disinfection applications.

    Science.gov (United States)

    Danwittayakul, Supamas; Songngam, Supachai; Fhulua, Tipawan; Muangkasem, Panida; Sukkasi, Sittha

    2017-08-01

    Solar water disinfection (SODIS) is a simple point-of-use process that uses sunlight to disinfect water for drinking. Polyethylene terephthalate (PET) bottles are typically used as water containers for SODIS, but a new SODIS container design has recently been developed with low-density polyethylene (LDPE) bags and can overcome the drawbacks of PET bottles. Two nesting layers of LDPE bags are used in the new design: the inner layer containing the water to be disinfected and the outer one creating air insulation to minimize heat loss from the water to the surroundings. This work investigated the degradation of LDPE bags used in the new design in actual SODIS conditions over a period of 12 weeks. The degradation of the LDPE bags was investigated weekly using a scanning electron microscope, Fourier transform infrared spectroscopy, ultraviolet-visible spectrophotometer, and tensile strength tester. It was found that the LDPE bags gradually degraded under the sunlight due to photo-oxidation reactions, especially in the outer bags, which were directly exposed to the sun and surroundings, leading to the reduction of light transmittance (by 11% at 300 nm) and tensile strength (by 33%). In addition, possible leaching of organic compounds into the water contained in the inner bags was examined using gas chromatography-mass spectrometer. 2,4-Di-tert-butylphenol was found in some SODIS water samples as well as the as-received water samples, in the concentration range of 1-4 μg/L, which passes the Environmental Protection Agency Drinking Water Guidance on Disinfection By-Products.

  19. Formation of secondary products in water purification. ; Charactarization of chlorination by-products. Josui shori ni okeru fukuseiseibutsu. ; Enso shori ni yoru shodoku fukuseiseibutsu no seisei tokusei

    Energy Technology Data Exchange (ETDEWEB)

    Aizawa, T [The Inst. of Public Health, Tokyo (Japan)

    1993-12-10

    Chlorination of drinking water is an inevitable process for the purification of drinking water. It has been made clear that injected free chlorine reacts with organic matter in water to produce chlorinated by-products. Many of those compounds are toxic, and studies have been made on the international water quality standard. Water quality standard has been revised also in Japan. The sources of organic matter which is the cause for production of chlorinated by-products vary according to the kinds and conditions of the water source for drinking water. Removal of precursors in the original water, removal of by-products, and change in the disinfection system with alternate disinfectant for chlorine are among the measures for decreasing chlorinated by-products at water purification plants, but the first one is employed as the basis method. It is expected that more severe regulation may be imposed on the quality of the water source for drinking water, and more strict oxidation and disinfection systems is inevitable for water management based on the new water quality standard. 10 refs., 5 figs., 2 tabs.

  20. Assessment of Color Changes in Vita 3D-Master Shade Guide after Sterilization and Disinfection

    Directory of Open Access Journals (Sweden)

    Hossein Dashti

    2017-06-01

    Full Text Available Purpose:Dental shade guides are commonly used for color determination and should be disinfected and sterilized. The purpose of this study was to evaluate the color change of Vita 3D Master shade tabs after disinfection and sterilization. Material and methods:Overall, 98 samples (shade tabs were randomly selected from 14 new, unused Vita 3D sets, including the following shades: 2M1, 3L1.5, 3M1, 3M2, 3M3, 3R1.5 and 4M1. In each set, values of 2, 3 and 4, chroma of 1, 2 and 3 and hue were selected for the comparison of different shades. All tabs were measured using the Vita Easyshade device at baseline. The first group was disinfected with Deconex and the second group was sterilized by autoclaving in a simulated annual application. All the tabs were measured again using the same device. This process was repeated to simulate 2 and 3 years of usage. Statistical analysis was conducted by repeated measures analysis of variance (ANOVA and independent t-test and paired sample t-test. Results:In the disinfected group, we observed significant differences in value and chroma in all periods (p˂0.001. However, hue showed no significant difference after the first year of simulated treatment (p=0.527, though it was significantly different in the second and third simulations (p˂0.001. In the sterilized group, all variables showed a significant difference for each year (p˂0.05. Considering total color difference (ΔE, there was a significant difference between the two groups in the first, second and third simulated years; ΔE increased in the sterilized group more than in the disinfected samples (p˂0.001.  Conclusions:  The color change of shade tabs was significant both after disinfection by a chemical solution and by sterilization through autoclaving. However, although disinfectants may not have a clinically important effect, sterilization should be considered as an interfering factor during color-matching procedure.

  1. Less skin irritation from alcohol-based disinfectant than from detergent used for hand disinfection

    DEFF Research Database (Denmark)

    Pedersen, L K; Held, E; Johansen, J D

    2005-01-01

    and forearms of 17 healthy volunteers. A control area was included. After 4 weeks an SLS patch was applied to each area. Irritant reactions were quantified with a visual score recording and measurements of transepidermal water loss (TEWL) and skin colour were performed on days 1, 5, 11, 38 and 40. RESULTS...... was found on the disinfectant-treated area compared with the control area and detergent area, and a similar trend was found for TEWL, although it was not statistically significant. CONCLUSION: Alcohol-based disinfectant caused less visible skin irritation and less skin barrier disruption than the use...

  2. Effect of ozonation of swimming pool water on formation of volatile disinfection by-products - A laboratory study

    DEFF Research Database (Denmark)

    Hansen, Kamilla Marie Speht; Spiliotopoulou, Aikaterini; Cheema, Waqas Akram

    2016-01-01

    Ozonation experiments were performed using unchlorinated tap water used for filling municipal swimming pools, actual pool water and pool water polluted by addition of fresh tap water and artificial body fluid to evaluate ozone kinetics and water quality effects on formation of volatile disinfecti...

  3. FORMATION OF N-NITROSODIMETHYLAMINE (NDMA) FROM REACTION OF MONOCHLORAMINE: A NEW DISINFECTION BY-PRODUCT. (R826832)

    Science.gov (United States)

    Studies have been conducted specifically to investigate the hypothesis that N-nitrosodimethylamine (NDMA) can be produced by reactions involving monochloramine. Experiments were conducted using dimethylamine (DMA) as a model precursor. NDMA was formed from the reaction ...

  4. Evaluating the Similarity of Complex Drinking-Water Disinfection By-Product Mixtures: Overview of the Issues

    Science.gov (United States)

    The Presentation describes the advantages and challenges of working with Whole Mixtures, discusses an exploratory approach for evaluating sufficient similarity, and challenges of applying such approaches to other environmental mixtures.

  5. Reducing Volatile Disinfection By-Products in Treated Drinking Water Using Aeration Technologies (WaterRF Report 4441)

    Science.gov (United States)

    The primary objective of this project was to evaluate cost-effective aeration technology solutions to address TTHM compliance at a water treatment plant clearwell. The project team worked closely with EPA Region 6 and the EPA Office of Research and Development (ORD) to identify a...

  6. The reactivity of natural organic matter to disinfection by-products formation and its relation to specific ultraviolet absorbance.

    Science.gov (United States)

    Kitis, M; Karanfil, T; Kilduff, J E; Wigton, A

    2001-01-01

    Five natural waters with a broad range of DOC concentrations were fractionated using various coal- and wood-based granular activated carbons (GAC) and alum coagulation. Adsorption and alum coagulation fractionated NOM solutions by preferentially removing components having high specific ultraviolet absorbance (SUVA). UV absorbing fractions of NOM were found to be the major contributors to DBP formation. SUVA appears to be an accurate predictor of reactivity with chlorine in terms of DBP yield; however, it was also found that low-SUVA components of NOM have higher bromine incorporation. SUVA has promise as a parameter for on-line monitoring and control of DBP formation in practical applications; however, the effects of bromide concentration may also need to be considered. Understanding how reactivity is correlated to SUVA may allow utilities to optimize the degree of treatment required to comply with DBP regulations. The reactive components that require removal, and the degree of treatment necessary to accomplish this removal, may be directly obtained from the relationship between SUVA removal and the degree of treatment (e.g., alum dose).

  7. Technology for recovery of by-products

    International Nuclear Information System (INIS)

    Van Tuy, H.H.

    1983-01-01

    Products of conventional nuclear fuel processing plants are uranium and plutonium, and any other recovered material is considered to be a by-product. Some by-products have been recovered from past nuclear fuel processing operations, either as a normal mode of operation or by special campaigns. Routing recovery over an extended period has been limited to neptunium, but extended campaigns were used at Hanford to recover strontium for radioisotope thermoelectric generators. Krypton is recovered at Idaho Chemical Processing Plant on a campaign basis, and isotope separation of krypton is done at Oak Ridge National Laboratory. Past campaigns at Hanford PUREX have recovered cesium, promethium, amercium, cerium, and technetium. Past by-product recovery efforts were usually severely constrained by the status of flowsheet development and availability of existing facilities at the time decisions wee made to recover the by-products. Additional processes were developed to accommodate other unit operations and in response to changes in waste management objectives or user requirements. Now an impressive variety of recovery technology is available for most potential by-products, with varying degrees of demonstration under conditions which satisfy today's environmental protection and waste management constraints

  8. Anaerobic digestion of slaughterhouse by-products

    International Nuclear Information System (INIS)

    Hejnfelt, Anette; Angelidaki, Irini

    2009-01-01

    Anaerobic digestion of animal by-products was investigated in batch and semi-continuously fed, reactor experiments at 55 o C and for some experiments also at 37 o C. Separate or mixed by-products from pigs were tested. The methane potential measured by batch assays for meat- and bone flour, fat, blood, hair, meat, ribs, raw waste were: 225, 497, 487, 561, 582, 575, 359, 619 dm 3 kg -1 respectively, corresponding to 50-100% of the calculated theoretical methane potential. Dilution of the by-products had a positive effect on the specific methane yield with the highest dilutions giving the best results. High concentrations of long-chain fatty acids and ammonia in the by-products were found to inhibit the biogas process at concentrations higher than 5 g lipids dm -3 and 7 g N dm -3 respectively. Pretreatment (pasteurization: 70 o C, sterilization: 133 o C, and alkali hydrolysis (NaOH) had no effect on achieved methane yields. Mesophilic digestion was more stable than thermophilic digestion, and higher methane yield was noticed at high waste concentrations. The lower yield at thermophilic temperature and high waste concentration was due to ammonia inhibition. Co-digestion of 5% pork by-products mixed with pig manure at 37 o C showed 40% higher methane production compared to digestion of manure alone.

  9. Anaerobic digestion of slaughterhouse by-products

    Energy Technology Data Exchange (ETDEWEB)

    Hejnfelt, Anette; Angelidaki, Irini [Department of Environmental Engineering, Technical University of Denmark, DTU, Building 113, DK-2800 Kgs. Lyngby (Denmark)

    2009-08-15

    Anaerobic digestion of animal by-products was investigated in batch and semi-continuously fed, reactor experiments at 55 C and for some experiments also at 37 C. Separate or mixed by-products from pigs were tested. The methane potential measured by batch assays for meat- and bone flour, fat, blood, hair, meat, ribs, raw waste were: 225, 497, 487, 561, 582, 575, 359, 619 dm{sup 3} kg{sup -1} respectively, corresponding to 50-100% of the calculated theoretical methane potential. Dilution of the by-products had a positive effect on the specific methane yield with the highest dilutions giving the best results. High concentrations of long-chain fatty acids and ammonia in the by-products were found to inhibit the biogas process at concentrations higher than 5 g lipids dm{sup -3} and 7 g N dm{sup -3} respectively. Pretreatment (pasteurization: 70 C, sterilization: 133 C), and alkali hydrolysis (NaOH) had no effect on achieved methane yields. Mesophilic digestion was more stable than thermophilic digestion, and higher methane yield was noticed at high waste concentrations. The lower yield at thermophilic temperature and high waste concentration was due to ammonia inhibition. Co-digestion of 5% pork by-products mixed with pig manure at 37 C showed 40% higher methane production compared to digestion of manure alone. (author)

  10. Effectiveness of current disinfection procedures against biofilm on contaminated GI endoscopes.

    Science.gov (United States)

    Neves, Marcelo S; da Silva, Marlei Gomes; Ventura, Grasiella M; Côrtes, Patrícia Barbur; Duarte, Rafael Silva; de Souza, Heitor S

    2016-05-01

    Attention to patient safety has increased recently due to outbreaks of nosocomial infections associated with GI endoscopy. The aim of this study was to evaluate current cleaning and disinfection procedures of endoscope channels with high bioburden and biofilm analysis, including the use of resistant mycobacteria associated with postsurgical infections in Brazil. Twenty-seven original endoscope channels were contaminated with organic soil containing 10(8) colony-forming units/mL of Pseudomonas aeruginosa, Staphylococcus aureus, or Mycobacterium abscessus subsp bolletii. Biofilms with the same microorganisms were developed on the inner surface of channels with the initial inoculum of 10(5) colony-forming units/mL. Channels were reprocessed following current protocol, and samples from cleaning and disinfection steps were analyzed by bioluminescence for adenosine triphosphate, cultures for viable microorganisms, and confocal microscopy. After contamination, adenosine triphosphate levels increased dramatically, and high bacterial growth was observed in all cultures. After cleaning, adenosine triphosphate levels decreased to values comparable to precontamination levels, and bacterial growth was demonstrated in 5 of 27 catheters, 2 with P aeruginosa and 3 with M abscessus. With regard to induced biofilm, a remarkable reduction occurred after cleaning, but significant microbial growth inhibition occurred only after disinfection. Nevertheless, viable microorganisms within the biofilm were still detected by confocal microscopy, more so with glutaraldehyde than with peracetic acid or O-phataladehyde. After the complete disinfection procedure, viable microorganisms could still be detected within the biofilm on endoscope channels. Prevention of biofilm development within endoscope channels should be a priority in disinfection procedures, particularly for ERCP and EUS. Copyright © 2016 American Society for Gastrointestinal Endoscopy. Published by Elsevier Inc. All rights

  11. Real-time ArcGIS and heterotrophic plate count based chloramine disinfectant control in water distribution system.

    Science.gov (United States)

    Bai, Xiaohui; Zhi, Xinghua; Zhu, Huifeng; Meng, Mingqun; Zhang, Mingde

    2015-01-01

    This study investigates the effect of chloramine residual on bacteria growth and regrowth and the relationship between heterotrophic plate counts (HPCs) and the concentration of chloramine residual in the Shanghai drinking water distribution system (DWDS). In this study, models to control HPCs in the water distribution system and consumer taps are also developed. Real-time ArcGIS was applied to show the distribution and changed results of the chloramine residual concentration in the pipe system by using these models. Residual regression analysis was used to get a reasonable range of the threshold values that allows the chloramine residual to efficiently inhibit bacteria growth in the Shanghai DWDS; the threshold values should be between 0.45 and 0.5 mg/L in pipe water and 0.2 and 0.25 mg/L in tap water. The low residual chloramine value (0.05 mg/L) of the Chinese drinking water quality standard may pose a potential health risk for microorganisms that should be improved. Disinfection by-products (DBPs) were detected, but no health risk was identified.

  12. 21 CFR 880.6890 - General purpose disinfectants.

    Science.gov (United States)

    2010-04-01

    ... (CONTINUED) MEDICAL DEVICES GENERAL HOSPITAL AND PERSONAL USE DEVICES General Hospital and Personal Use... disinfectant is a germicide intended to process noncritical medical devices and equipment surfaces. A general... prior to terminal sterilization or high level disinfection. Noncritical medical devices make only...

  13. [Scanning electron microscope study of chemically disinfected endodontic files].

    Science.gov (United States)

    Navarro, G; Mateos, M; Navarro, J L; Canalda, C

    1991-01-01

    Forty stainless steel endodontic files were observed at scanning electron microscopy after being subjected to ten disinfection cycles of 10 minutes each one, immersed in different chemical disinfectants. Corrosion was not observed on the surface of the files in circumstances that this study was made.

  14. The antimicrobial activities of some commonly used disinfectants on ...

    African Journals Online (AJOL)

    The disinfectants; SavlonR, JikR, Methylated spirit and kerosene were observed for their inhibitory activities on Bacillus subtilis, Pseudomonas aeruginosa and Candida albicans. This was done by measuring the zone of inhibition of the disinfectants on the tested organisms. The results showed that Savlon was very effective ...

  15. Microbial contamination of disinfectant solutions in some health care ...

    African Journals Online (AJOL)

    Commonly used disinfectants in some health institutions in three major towns of northern Nigeria were examined for presence of bacteria contamination. For each disinfectant, stock, freshly diluted and left-over of used diluted samples were analyzed. All the stock samples were free of bacteria contaminants while 52.17% of ...

  16. HIGH-RATE DISINFECTION TECHNIQUES FOR COMBIND SEWER OVERFLOW

    Science.gov (United States)

    This paper presents high-rate disinfection technologies for combined sewer overflow (CSO). The high-rate disinfection technologies of interest are: chlorination/dechlorination, ultraviolet light irradiation (UV), chlorine dioxide (ClO2 ), ozone (O3), peracetic acid (CH3COOOH )...

  17. Peracetic Acid as a Green Disinfectant for Combined Sewer Overflows

    Science.gov (United States)

    This cooperative research and development agreement between U.S. EPA, Solvay, MSDGC, and CB&I is evaluating the potential of PAA for disinfection of Muddy Creek CSO wastewater and comparing that with sodium hypochlorite disinfection. This presentation will document the effectiven...

  18. Disinfectant effect of Methylated Ethanol against Listeria species

    Directory of Open Access Journals (Sweden)

    Y Yakubu

    2012-04-01

    Full Text Available This study was carried out in order to determine the disinfectant effect of Methylated spirit® (95% methanol and 5% ethanol as a teat dip against Listeria species. Hand milking was employed to collect 576 (288 x 2 raw milk samples from different lactating cows within Sokoto metropolis (Nigeria. 288 samples were collected before disinfecting the udder teats with Methylated spirit®, while the other 288 were collected after disinfection with Methylated spirit®. The samples were analyzed using selective culture and isolation technique in which the 288 samples collected before disinfection, 114 (39.6% were positive for Listeria species. Among the positive samples 44 (38.6% were Listeria innocua, 16 (14.0% Listeria ivanovii, 36 (31.6% Listeria monocytogenes, 11 (9.6% Listeria welshimeri and 7 (6.1% Listeria seeligeri, while none of the 288 samples collected after disinfection was positive. The study has shown high prevalence of Listeria species in milk collected without washing/disinfecting the teats and has also established the sensitivity of Listeria species to methylated ethanol which can be used as dip for disinfecting udder teats before milking in order to prevent contamination with Listeria species and other methylated spirit-sensitive organisms. This study is essential to educate Fulani herdsmen and other milk handlers on the importance of disinfecting udder teats before milking. [Vet. World 2012; 5(2.000: 91-93

  19. Evaluation of hospital disinfection as a means of controlling endemic ...

    African Journals Online (AJOL)

    Evaluation of hospital environment disinfection as a means of controlling endemic nosocomial pathogens in a University Teaching Hospital in Nigeria was evaluated. Disinfectant used in the Hospital was collected from the Infection Control unit and prepared in different concentrations. The isolated bacterial species from the ...

  20. Nanomaterial Case Study: Nanoscale Silver in Disinfectant Spray (Final Report)

    Science.gov (United States)

    EPA announced the release of the final report, Nanomaterial Case Study: Nanoscale Silver in Disinfectant Spray. This report represents a case study of engineered nanoscale silver (nano-Ag), focusing on the specific example of nano-Ag as possibly used in disinfectant spr...

  1. Disinfection studies of Nahar (Mesua ferrea) seed kernel oil using ...

    African Journals Online (AJOL)

    GREGORY

    2011-12-16

    Dec 16, 2011 ... with a k value of -0.040. Key words: Nahar (Mesua ferrea) seed kernel oil, extraction, gum Arabic, disinfection, kinetics. INTRODUCTION. Disinfection plays a key role in the reclamation and reuse of wastewater for eliminating infectious diseases, this, in part, augments domestic water supply and decreases ...

  2. Candida auris: Disinfectants and Implications for Infection Control.

    Science.gov (United States)

    Ku, Tsun S N; Walraven, Carla J; Lee, Samuel A

    2018-01-01

    Candida auris is a rapidly emerging pathogen and is able to cause severe infections with high mortality rates. It is frequently misidentified in most clinical laboratories, thus requiring more specialized identification techniques. Furthermore, several clinical isolates have been found to be multidrug resistant and there is evidence of nosocomial transmission in outbreak fashion. Appropriate infection control measures will play a major role in controlling the management and spread of this pathogen. Unfortunately, there are very few data available on the effectiveness of disinfectants against C. auris . Chlorine-based products appear to be the most effective for environmental surface disinfection. Other disinfectants, although less effective than chlorine-based products, may have a role as adjunctive disinfectants. A cleaning protocol will also need to be established as the use of disinfectants alone may not be sufficient for maximal decontamination of patient care areas. Furthermore, there are fewer data on the effectiveness of antiseptics against C. auris for patient decolonization and hand hygiene for healthcare personnel. Chlorhexidine gluconate has shown some efficacy in in vitro studies but there are reports of patients with persistent colonization despite twice daily body washes with this disinfectant. Hand hygiene using soap and water, with or without chlorhexidine gluconate, may require the subsequent use of alcohol-based hand sanitizer for maximal disinfection. Further studies will be needed to validate the currently studied disinfectants for use in real-world settings.

  3. Candida auris: Disinfectants and Implications for Infection Control

    Directory of Open Access Journals (Sweden)

    Tsun S. N. Ku

    2018-04-01

    Full Text Available Candida auris is a rapidly emerging pathogen and is able to cause severe infections with high mortality rates. It is frequently misidentified in most clinical laboratories, thus requiring more specialized identification techniques. Furthermore, several clinical isolates have been found to be multidrug resistant and there is evidence of nosocomial transmission in outbreak fashion. Appropriate infection control measures will play a major role in controlling the management and spread of this pathogen. Unfortunately, there are very few data available on the effectiveness of disinfectants against C. auris. Chlorine-based products appear to be the most effective for environmental surface disinfection. Other disinfectants, although less effective than chlorine-based products, may have a role as adjunctive disinfectants. A cleaning protocol will also need to be established as the use of disinfectants alone may not be sufficient for maximal decontamination of patient care areas. Furthermore, there are fewer data on the effectiveness of antiseptics against C. auris for patient decolonization and hand hygiene for healthcare personnel. Chlorhexidine gluconate has shown some efficacy in in vitro studies but there are reports of patients with persistent colonization despite twice daily body washes with this disinfectant. Hand hygiene using soap and water, with or without chlorhexidine gluconate, may require the subsequent use of alcohol-based hand sanitizer for maximal disinfection. Further studies will be needed to validate the currently studied disinfectants for use in real-world settings.

  4. Sewage disinfection towards protection of drinking water resources.

    Science.gov (United States)

    Kolch, A

    2000-01-01

    Wastewater applied in agriculture for irrigation could replace the use of natural drinking-water resources. With respect to high concentrations of human pathogens wastewater has to be disinfected prior to use. This paper introduces disinfection methods with emphasis on UV irradiation.

  5. Endoscope disinfection and its pitfalls - requirement for retrograde surveillance cultures

    NARCIS (Netherlands)

    Buss, A. J.; Been, M. H.; Borgers, R. P.; Stokroos, I.; Melchers, W. J. G.; Peters, F. T. M.; Limburg, A. J.; Degener, J. E.

    Background and study aims: Several endoscopy-related outbreaks of infection have been reported in recent years. For early recognition of inadequate disinfection of endoscopes we designed a microbiological surveillance system to evaluate the efficacy of the cleaning and disinfection procedure, and to

  6. Disinfection of contaminated water by using solar irradiation.

    Science.gov (United States)

    Caslake, Laurie F; Connolly, Daniel J; Menon, Vilas; Duncanson, Catriona M; Rojas, Ricardo; Tavakoli, Javad

    2004-02-01

    Contaminated water causes an estimated 6 to 60 billion cases of gastrointestinal illness annually. The majority of these cases occur in rural areas of developing nations where the water supply remains polluted and adequate sanitation is unavailable. A portable, low-cost, and low-maintenance solar unit to disinfect unpotable water has been designed and tested. The solar disinfection unit was tested with both river water and partially processed water from two wastewater treatment plants. In less than 30 min in midday sunlight, the unit eradicated more than 4 log10 U (99.99%) of bacteria contained in highly contaminated water samples. The solar disinfection unit has been field tested by Centro Panamericano de Ingenieria Sanitaria y Ciencias del Ambiente in Lima, Peru. At moderate light intensity, the solar disinfection unit was capable of reducing the bacterial load in a controlled contaminated water sample by 4 log10 U and disinfected approximately 1 liter of water in 30 min.

  7. Impact of disinfection on drinking water biofilm bacterial community.

    Science.gov (United States)

    Mi, Zilong; Dai, Yu; Xie, Shuguang; Chen, Chao; Zhang, Xiaojian

    2015-11-01

    Disinfectants are commonly applied to control the growth of microorganisms in drinking water distribution systems. However, the effect of disinfection on drinking water microbial community remains poorly understood. The present study investigated the impacts of different disinfectants (chlorine and chloramine) and dosages on biofilm bacterial community in bench-scale pipe section reactors. Illumina MiSeq sequencing illustrated that disinfection strategy could affect both bacterial diversity and community structure of drinking water biofilm. Proteobacteria tended to predominate in chloraminated drinking water biofilms, while Firmicutes in chlorinated and unchlorinated biofilms. The major proteobacterial groups were influenced by both disinfectant type and dosage. In addition, chloramination had a more profound impact on bacterial community than chlorination. Copyright © 2015. Published by Elsevier B.V.

  8. Evaluation of an ultraviolet room disinfection protocol to decrease nursing home microbial burden, infection and hospitalization rates.

    Science.gov (United States)

    Kovach, Christine R; Taneli, Yavuz; Neiman, Tammy; Dyer, Elaine M; Arzaga, Alvin Jason A; Kelber, Sheryl T

    2017-03-03

    The focus of nursing home infection control procedures has been on decreasing transmission between healthcare workers and residents. Less evidence is available regarding whether decontamination of high-touch environmental surfaces impacts infection rates or resident outcomes. The purpose of this study was to examine if ultraviolet disinfection is associated with changes in: 1) microbial counts and adenosine triphosphate counts on high-touch surfaces; and 2) facility wide nursing home acquired infection rates, and infection-related hospitalization. The study was conducted in one 160-bed long-term care facility. Following discharge of each resident, their room was cleaned and then disinfected using a newly acquired ultraviolet light disinfection device. Shared living spaces received weekly ultraviolet light disinfection. Thirty-six months of pretest infection and hospitalization data were compared with 12 months of posttest data. Pre and posttest cultures were taken from high-touch surfaces, and luminometer readings of adenosine triphosphate were done. Nursing home acquired infection rates were analyzed relative to hospital acquired infection rates using analysis of variance procedures. Wilcoxon signed rank tests, The Cochran's Q, and Chi Square were also used. There were statistically significant decreases in adenosine triphosphate readings on all high-touch surfaces after cleaning and disinfection. Culture results were positive for gram-positive cocci or rods on 33% (n = 30) of the 90 surfaces swabbed at baseline. After disinfectant cleaning, 6 of 90 samples (7.1%) tested positive for a gram-positive bacilli, and after ultraviolet disinfection 4 of the 90 samples (4.4%) were positive. There were significant decreases in nursing home acquired relative to hospital-acquired infection rates for the total infections (p = .004), urinary tract infection rates (p = .014), respiratory system infection rates (p = .017) and for rates of infection of the skin

  9. Disinfection of drinking water by ultraviolet light

    International Nuclear Information System (INIS)

    Anon.

    1977-01-01

    It is no longer mandatory that a given residue of chlorine is present in drinking water and this has led to interest in the use of ultraviolet radiation for disinfection of water in large public waterworks. After a brief discussion of the effect of ultraviolet radiation related to wavelength, the most usual type of irradiation equipment is briefly described. Practioal considerations regarding the installation, such as attenuation of the radiation due to water quality and deposits are presented. The requirements as to dose and residence time are also discussed and finally it is pointed out that hydraulic imperfections can reduce the effectiveness drastically. (JIW)Ψ

  10. The role of surface disinfection in infection prevention

    Science.gov (United States)

    Gebel, Jürgen; Exner, Martin; French, Gary; Chartier, Yves; Christiansen, Bärbel; Gemein, Stefanie; Goroncy-Bermes, Peter; Hartemann, Philippe; Heudorf, Ursel; Kramer, Axel; Maillard, Jean-Yves; Oltmanns, Peter; Rotter, Manfred; Sonntag, Hans-Günther

    2013-01-01

    Background: The Rudolf Schuelke Foundation addresses topics related to hygiene, infection prevention and public health. In this context a panel of scientists from various European countries discussed “The Role of Surface Disinfection in Infection Prevention”. The most important findings and conclusions of this meeting are summarised in the present consensus paper. Aim: Although the relevance of surface disinfection is increasingly being accepted, there are still a number of issues which remain controversial. In particular, the following topics were addressed: Transferral of microbes from surface to patients as a cause of infection, requirements for surface disinfectants, biocidal resistance and toxicity, future challenges. Methods and findings: After discussion and review of current scientific literature the authors agreed that contaminated surfaces contribute to the transmission of pathogens and may thus pose an infection hazard. Targeted surface disinfection based on a risk profile is seen as an indispensable constituent in a multibarrier approach of universal infection control precautions. Resistance and cross-resistance depend on the disinfectant agent as well as on the microbial species. Prudent implementation of surface disinfection regimens tested to be effective can prevent or minimize adverse effects. Conclusions: Disinfection must be viewed as a holistic process. There is a need for defining standard principles for cleaning and disinfection, for ensuring compliance with these principles by measures such as written standard operating procedures, adequate training and suitable audit systems. Also, test procedures must be set up in order to demonstrate the efficacy of disinfectants including new application methods such as pre-soaked wipes for surface disinfection. PMID:23967396

  11. The role of surface disinfection in infection prevention

    Directory of Open Access Journals (Sweden)

    Gebel, Jürgen

    2013-04-01

    Full Text Available [english] Background: The Rudolf Schuelke Foundation addresses topics related to hygiene, infection prevention and public health. In this context a panel of scientists from various European countries discussed “The Role of Surface Disinfection in Infection Prevention”. The most important findings and conclusions of this meeting are summarised in the present consensus paper.Aim: Although the relevance of surface disinfection is increasingly being accepted, there are still a number of issues which remain controversial. In particular, the following topics were addressed: Transferral of microbes from surface to patients as a cause of infection, requirements for surface disinfectants, biocidal resistance and toxicity, future challenges.Methods and findings: After discussion and review of current scientific literature the authors agreed that contaminated surfaces contribute to the transmission of pathogens and may thus pose an infection hazard. Targeted surface disinfection based on a risk profile is seen as an indispensable constituent in a multibarrier approach of universal infection control precautions. Resistance and cross-resistance depend on the disinfectant agent as well as on the microbial species. Prudent implementation of surface disinfection regimens tested to be effective can prevent or minimize adverse effects.Conclusions: Disinfection must be viewed as a holistic process. There is a need for defining standard principles for cleaning and disinfection, for ensuring compliance with these principles by measures such as written standard operating procedures, adequate training and suitable audit systems. Also, test procedures must be set up in order to demonstrate the efficacy of disinfectants including new application methods such as pre-soaked wipes for surface disinfection.

  12. Ultraviolet light in the use of water disinfection

    International Nuclear Information System (INIS)

    Dabbagh, R.

    1999-01-01

    Ultraviolet light is an effective method in the use of water disinfection for swimming pools, potable water and industry required water. For many reasons Ultraviolet light and Ultraviolet compounded with chlorine (Ultraviolet/chlorine) has been brought to attention ed in resent years. In this research, a swimming pool water disinfection was carried out by means of a system with the use of a reactor which was made of stainless steel (SS-304) and with many another standards required. Operation of system was carried out at first in the pilot plant and then installation in essential water treatment integrated. Inactivation of pollution index, E. Coli or Total coliform and Pseudomonas aeroginosa studies with 6000,16000 and 30000 μW.s/cm 2 Ultraviolet dose and then in presence of 0.3,0.6,0.9 and 1.2 mg/1 free chlorine (Ultraviolet/chlorine). In swimming pools minimum free chlorine residual usually is 1.5 mg/1. Optimum Ultraviolet dose was 16000 μW.s/cm 2 attention to 50 percent Ultraviolet absorption ca sued to TSS,TDS and turbidity. In the Ultraviolet/chlorine system suitable rate was 16000μW.s/cm 2 Ultraviolet dose/0.6 mg/1 chlorine in the 2.4 * 10 5 CFU/100 ml for Total coliform and 3600 CFU/100 ml for Pseudomonas aeroginosa. Most probable number (MPN) estimated multiple tube fermentation technique. In this way the flow rate for system indicated about 240 cm 3 /s or 0.9 m 3 /h. The samples polluted for secondary pollution with 54000 CFU/100 ml for E. Coli and 1800 CFU/100ml Pseudomonas aeroginosa. The number of microbes decreased to zero duration after 45 minutes contact time in presence of free chlorine residual in samples. In practical conditions which that disinfectant system was installed in essential water treatment circuit under 1.4 atm hydraulic pressure no growth was seen for pollution index in disinfected water with Ultraviolet in microbial density about 840 CFU/100 ml for Total coliform and 12 CFU/100 ml for pseudomonas aeroginosa. Attention to lower

  13. Ultraviolet light in the use of water disinfection

    International Nuclear Information System (INIS)

    Dabbagh, R.

    1999-01-01

    Ultraviolet light is an effective method in the use of water disinfection for swimming pools, potable water and industry required water. For many reasons UV light and UV compounded with chlorine (UV/chlorine) has been brought to attention in resent years. In this research, a swimming pool water disinfection was carried out by means of a system with the use of a reactor which was made of stainless steel (SS-304) and with many another standards required. Operation of system was carried out at first in the pilot plant and then installation in essential water treatment integrated. Inactivation of pollution index, E. Coli or Total coliform and Pseudomonas aeroginosa studied with 6000,16000 and 30000 μW.s/cm 2 UV dose and then in presence of 0.3,0.6,0.9 and 1.2 mg/1 free chlorine (UV/chlorine). In swimming pools minimum free chlorine residual usually is 1.5 mg/1. Optimum UV dose was 16000 μW.s/cm 2 attention to 50 percent UV absorption caused to TSS,TDS and turbidity. In the UV/chlorine system suitable rate was 16000μW.s/cm 2 UV dose /0.6 mg/1 chlorine in the 2.4 * 10 5 CFU/100 ml for Total coliform and 3600CFU/100 ml for Pseudomonas aeroginosa. Most probable number(MPN) estimated multiple tube fermentation technique. In this way the flow rate for system indicated about 240 cm 3 /s or 0.9 m 3 /h. The samples polluted for secondary pollution with 54000 CFU/100 ml for E.Coli and 1800 CFU/100ml Pseudomonas aeroginosa. The number of microbes decreased to zero duration after 45 minutes contact time in presence of free chlorine residual in samples. In practical conditions which that disinfectant system was installed in essential water treatment circuit under 1.4 atm hydraulic pressure no growth was seen for pollution index in disinfected water with UV in microbial density about 840 CFU/100 ml for Total coliform and 12CFU/100 ml for Pseudomonas aeroginosa. Attention to lower turbidity, TSS and TDS in tap water, higher flow rate about 560 cm 3 /s or 2 m 3 /h acessesed

  14. 9 CFR 52.7 - Disinfection of premises, conveyances, and materials.

    Science.gov (United States)

    2010-01-01

    ... cleaning and disinfection, unless an official pseudorabies epidemiologist determines that a shorter or... and disinfection, except for cleaning and disinfection of the conveyances used to transport the swine... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Disinfection of premises, conveyances...

  15. 9 CFR 55.4 - Disinfection of premises, conveyances, and materials.

    Science.gov (United States)

    2010-01-01

    ... paid will be responsible for expenses incurred in connection with the cleaning and disinfection, except that APHIS or a State will pay for cleaning and disinfection of the conveyances used to transport the... disinfecting premises when the procedures needed to conduct effective cleaning and disinfection are unusually...

  16. Cleansing and Disinfection in the Food Industry

    Directory of Open Access Journals (Sweden)

    Ruhtan Baskaya

    2009-02-01

    Full Text Available In the applications of industrial hygiene, it is of utmost importance to define the potential risk factors in the business enterprise in question, to pay sufficient consideration to those factors, and to spend every effort for their checking and elimination. In that sense, cleansing and disinfection applications have a basic importance. Food hygiene covers all the efforts spent in order to ensure the proper conditions for the production of healthy food at every stage of the production process, extending from the farm to the table. Cleansing is the removal of the dirt or food leftovers found on the tools and equipment contacting food, and preventing their conversion into a convenient millieu for the reproduction of microorganisms. Cleansing is the process of removing not only the visible dirts and leftovers, but also a large part of the visible microorganisms. Disinfection is applied after cleansing; it is the process of disintegration of microorganisms which can cause contamination, or reduction of those microorganisms to minimum levels so that they can not create any harmful effects. [TAF Prev Med Bull 2009; 8(1.000: 93-106

  17. Wastewater disinfection with peracetic acid and UV

    International Nuclear Information System (INIS)

    Caretti, C.; Lubello, C.

    2001-01-01

    Was investigated the synergy between UV and peracetic acid (PAA) through a five months on-site experimental study in a pilot plant fed by the secondary effluent of the central wastewater treatment plant of Pistoia, Italy. This experiment is a part of a larger research project on advanced treatment for municipal wastewater reuse in agriculture. Because of Italy's strict limits on unrestricted wastewater reuse in agriculture (2 CFU total coliform/100 ml), a very high degree of disinfection is necessary. In the investigated experimental conditions, it has been impossible to meet such values through an exclusive use of UV irradiation (the UV unit reaches at most 4 Log inactivation). Low levels of PAA greatly enhance the decline of indicator levels, but higher unsustainable doses are required to hit the Italian limit. Through a poor amount of information on the subject was available in literature, it was tried to find out how the disinfection efficiency could improve by simultaneously using UV and PAA. It was found out that a combined treatment is satisfactory and that it is more advantage of the hydroxyl radicals formation due to the PAA photo lysis. The application of 2 ppm of PAA with an UV dose of 192 mWscm - 2 is enough to meet the Italian limit [it

  18. Quality control of disinfection in ultrasonic baths

    Energy Technology Data Exchange (ETDEWEB)

    Schoene, H. [Technical University Dresden (Germany). Faculty of Mechanical Engineering; Jatzwauk, L. [University Hospital of the Technical University Dresden (Germany). Abt. Krankenhaushygiene

    2002-07-01

    Numerous investigations under laboratory conditions confirmed the microbicidal efficacy of ultrasonication. Morphological destruction was shown on bacteria and fungi as well as on different virus species. Ultrasonic treatment seems to increase the effect of different antibiotics and disinfectants. Reasons for this synergism are largely unknown and uninvestigated, but the active principle seems to bee the dispersing effect of ultrasonication in combination with the destruction of cell wall or cell membrane. Unfortunately no validation of test conditions exists for most of these investigations, regarding intensity and frequency of ultrasonic waves, temperature of liquid medium and measurement of cavitation which is an essential part of physical and chemical effects in ultrasonic baths. In contrast to most laboratory experiments sound density of ultrasound for treatment of medical instruments is below 1 W/cm{sup 2} because instruments will be destroyed under stronger ultrasonic conditions. The frequency is below 50 KHz. This paper describes bactericidal and fungicidal effects of low- intensity-ultrasonication and its synergistical support to chemical disinfection. (orig.)

  19. Effects of disinfecting alginate impressions on the scratch hardness of stone models.

    Science.gov (United States)

    Hiraguchi, Hisako; Nakagawa, Hisami; Wakashima, Mitsuru; Miyanaga, Kohichi; Saigo, Masataka; Nishiyama, Minoru

    2006-03-01

    This study investigated the effects of disinfecting alginate impressions on the scratch depth of resultant stone models. Eleven brands of alginate impression material and two disinfectants, 1% sodium hypochlorite and 2% glutaraldehyde, were used. Impressions were immersed in disinfectant solutions or stored in sealed bags after spraying with disinfectants, and then poured with a type V dental stone. The scratch depth of the stone model obtained from disinfected impression was measured. The storage of alginate impressions after spraying with disinfectants did not increase the scratch depth of resultant stone models. However, the effect of immersion in disinfectants on scratch depth varied with the brand of the alginate impression material.

  20. Inactivation model for disinfection of biofilms in drinking water

    International Nuclear Information System (INIS)

    Karlicki, A.; O'Leary, K.C.; Gagnon, G.A.

    2002-01-01

    The purpose of the project was to investigate experimentally the effects of free chlorine, monochloramine and chlorine dioxide on the removal of biofilm growth in water as it applies to drinking water in distribution systems. In particular, biofilm kill for a particular dosage of disinfectant was measured as a function of time for each disinfectant over a range of disinfectant concentrations. These results were used to formulate concentration-time (Ct) inactivation values for each disinfectant to compare the efficacy of the three disinfectants for biofilm control. The biofilm reactor system consisted of a 125 mL columns, each containing tightly packed 3 mm glass beads on which heterotrophic bacterial biofilm is established. Following an initial biofilm inoculation period, the glass beads were removed from the columns and placed into glass jars for disinfection with free chlorine, monochloramine and chlorine dioxide. Cell counts were determined on a time series basis with the goal of achieving a Ct inactivation model that is similar to models presently used for inactivation of suspended cells. Ultimately this research could be used to develop a rationale method for setting regulatory values for secondary disinfection in drinking water distribution systems, which presently in only a few states and provinces. (author)

  1. ASSESSMENT OF ACTION OF DISINFECTANTS AGAINST LISTERIA MONOCYTOGENES BIOFILMS

    Directory of Open Access Journals (Sweden)

    T. K. CABEÇA

    2008-12-01

    Full Text Available

    The purpose of this study was to assess the action of various disinfectants used in food industry against biofilm cells of Listeria monocytogenes formed on stainless steel surfaces during 24, 72 and 120 hours. Numbers of viable biofilm cells decreased after treatment with all the tested disinfectants (iodine, biguanide, quaternary ammonium compounds, peracetic acid and sodium hypochlorite. Sodium hypochlorite was the most effective disinfectant against the biofilm cells, while biguanide and iodine were the least. Scanning electron microscopy observations demonstrated attached cells on stainless steel surfaces after treatment with all the disinfectants. These observations showed that microorganisms were not completely removed from stainless steel surfaces after treatment with the disinfectants, however, the attachment did not means the viability of remaining cells. The biofilm age in hours (24, 72 and 120 had no apparent influence on resistance of microbiological cells to the disinfectants under study. In conclusion biofilm cells of L. monocytogenes can withstand disinfectants action.

  2. Efficacy of a variety of disinfectants against Listeria spp.

    Science.gov (United States)

    Best, M; Kennedy, M E; Coates, F

    1990-02-01

    The efficacy of 14 disinfectants against Listeria innocua and two strains of Listeria monocytogenes in the presence of organic matter was studied. Quantitative efficacy tests were used. Many of the disinfectants tested were not as effective on Listeria spp. when the test organisms were dried onto the surface of steel disks (carrier tests) as they were when the organisms were placed in suspension (suspension test). The presence of whole serum and milk (2% fat) further reduced the disinfectant capacities of most of the formulations studied. Only three disinfectants (povidone-iodine, chlorhexidine gluconate, and glutaraldehyde) were effective in the carrier test in the presence of serum; however, all three were ineffective when challenged with milk (2% fat). Only one solution, sodium dichloroisocyanurate, was effective in the presence of milk. All but four formulations (chloramine-T, phosphoric acid, an iodophor, and formaldehyde) were effective in the suspension tests, regardless of the organic load. L. monocytogenes was observed to be slightly more resistant to disinfection than L. innocua was. There was no difference in disinfectant susceptibility between the two strains of L. monocytogenes. These findings emphasize the need for caution in selecting an appropriate disinfectant for use on contaminated surfaces, particularly in the presence of organic material.

  3. Inactivation kinetics of spores of Bacillus cereus strains treated by a peracetic acid-based disinfectant at different concentrations and temperatures.

    Science.gov (United States)

    Sudhaus, Nadine; Pina-Pérez, Maria Consuelo; Martínez, Antonio; Klein, Günter

    2012-05-01

    The purpose of this study was to assess the effect of a commercial peracetic acid-based disinfectant against spores of Bacillus cereus, to identify the most influential factor for the final number of microorganisms after different disinfection procedures, and to evaluate the nature of the inactivation kinetics. The spores of four different strains of B. cereus (DSM 318, 4312, 4313, and 4384) were treated with five different disinfectant concentrations (0.25%, 0.5%, 1.0%, 1.5%, and 2.0% [w/v]) at three different temperatures (10°C, 15°C, and 20°C) with or without protein load. A higher temperature and PES 15/23 concentration resulted in a higher inactivation. Inactivation of B. cereus strain 4312 was around 2 log₁₀ cycles at 10°C and around 7 log₁₀ at 20°C (conc=1% [w/v] PAA; t=60 min; without protein). The protein load at higher concentrations did not significantly reduce the efficacy of the disinfectant (p>0.05). This article indicates the applicability of the Weibull model to fit the B. cereus disinfectant survival curves. A Monte Carlo simulation was used to carry out a sensitivity analysis, which revealed the most influential factors affecting the final number of microorganisms after the disinfection process.

  4. Do European Standard Disinfectant tests truly simulate in-use microbial and organic soiling conditions on food preparation surfaces?

    Science.gov (United States)

    Meyer, B; Morin, V N; Rödger, H-J; Holah, J; Bird, C

    2010-04-01

    The results from European standard disinfectant tests are used as one basis to approve the use of disinfectants in Europe. The design of these laboratory-based tests should thus simulate as closely as possible the practical conditions and challenges that the disinfectants would encounter in use. No evidence is available that the organic and microbial loading in these tests simulates actual levels in the food service sector. Total organic carbon (TOC) and total viable count (TVC) were determined on 17 visibly clean and 45 visibly dirty surfaces in two restaurants and the food preparation surfaces of a large retail store. These values were compared to reference values recovered from surfaces soiled with the organic and microbial loading, following the standard conditions of the European Surface Test for bactericidal efficacy, EN 13697. The TOC reference values for clean and dirty conditions were higher than the data from practice, but cannot be regarded as statistical outliers. This was considered as a conservative assessment; however, as additional nine TOC samples from visibly dirty surfaces were discarded from the analysis, as their loading made them impossible to process. Similarly, the recovery of test organisms from surfaces contaminated according to EN 13697 was higher than the TVC from visibly dirty surfaces in practice; though they could not be regarded as statistical outliers of the whole data field. No correlation was found between TVC and TOC in the sampled data, which re-emphasizes the potential presence of micro-organisms on visibly clean surfaces and thus the need for the same degree of disinfection as visibly dirty surfaces. The organic soil and the microbial burden used in EN disinfectant standards represent a realistic worst-case scenario for disinfectants used in the food service and food-processing areas.

  5. Persistence of mixed staphylococci assemblages following disinfection of hospital room surfaces.

    Science.gov (United States)

    Sigler, V; Hensley, S

    2013-03-01

    The distribution of staphylococcal assemblages on surfaces in hospital rooms was assessed before and after daily disinfection with quaternary ammonia products. DNA was extracted from enrichment cultures of bacteria, which were swabbed from each of nine surface types, and subjected to analysis by staphylococci-specific, denaturing gradient gel electrophoresis. A genetic marker for Staphylococcus epidermidis/kloosii was detected on all surface types before and after cleaning, whereas markers for Staphylococcus aureus and Staphylococcus lugdunensis were detected on five surface types. Overall, genetic makers for several staphylococci known to colonize and infect humans remained ubiquitous in each room following daily disinfection practices. Copyright © 2013 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

  6. Evaluation of calcium hydrogen carbonate mesoscopic crystals as a disinfectant for influenza A viruses

    Science.gov (United States)

    NAKASHIMA, Ryuji; KAWAMOTO, Masaomi; MIYAZAKI, Shigeru; ONISHI, Rumiko; FURUSAKI, Koichi; OSAKI, Maho; KIRISAWA, Rikio; SAKUDO, Akikazu; ONODERA, Takashi

    2017-01-01

    In this study, the virucidal effect of a novel electrically charged disinfectant CAC-717 was investigated. CAC-717 is produced by applying an electric field to mineral water containing calcium hydrogen carbonate to generate mesoscopic crystals. Virus titration analysis showed a >3 log reduction of influenza A viruses after treatment with CAC-717 for 1 min in room temperature, while infectivity was undetectable after 15 min treatment. Adding bovine serum albumin to CAC-717 solution did not affect the disinfectant effect. Although CAC-717 is an alkaline solution (pH=12.39), upon contact with human tissue, its pH becomes almost physiological (pH 8.84) after accelerated electric discharge, which enables its use against influenza viruses. Therefore, CAC-717 may be used as a preventative measure against influenza A viruses and for biosecurity in the environment. PMID:28392537

  7. Drinking Water Supply without Use of a Disinfectant

    Science.gov (United States)

    Rajnochova, Marketa; Tuhovcak, Ladislav; Rucka, Jan

    2018-02-01

    The paper focuses on the issue of drinking water supply without use of any disinfectants. Before the public water supply network operator begins to consider switching to operation without use of chemical disinfection, initial assessment should be made, whether or not the water supply system in question is suitable for this type of operation. The assessment is performed by applying the decision algorithm. The initial assessment is followed by another decision algorithm which serves for managing and controlling the process of switching to drinking water supply without use of a disinfectant. The paper also summarizes previous experience and knowledge of this way operated public water supply systems in the Czech Republic.

  8. Sterilization, high-level disinfection, and environmental cleaning.

    Science.gov (United States)

    Rutala, William A; Weber, David J

    2011-03-01

    Failure to perform proper disinfection and sterilization of medical devices may lead to introduction of pathogens, resulting in infection. New techniques have been developed for achieving high-level disinfection and adequate environmental cleanliness. This article examines new technologies for sterilization and high-level disinfection of critical and semicritical items, respectively, and because semicritical items carry the greatest risk of infection, the authors discuss reprocessing semicritical items such as endoscopes and automated endoscope reprocessors, endocavitary probes, prostate biopsy probes, tonometers, laryngoscopes, and infrared coagulation devices. In addition, current issues and practices associated with environmental cleaning are reviewed. Copyright © 2011. Published by Elsevier Inc.

  9. Nutritional Value of Irradiated Animal Feed By-Products

    International Nuclear Information System (INIS)

    El-Din Farag, M.D.H.

    1998-01-01

    Animal feed by-products, widely used in animal diets, are sources of disease organisms for animals and for human beings. Salmonella is the principal genus of concern.Radiation treatment (radicidation, radurization) is a promising method of decontamination of feed ingredients. Commercial samples of fish, meat, and blood meals were sealed by heat in polyethylene bags and irradiated at dose levels of 5.0, 10, 20 and 50 kGy. Their chemical analysis were carried out according to A. O. A.C [1] and the total protein efficiency (TPE) of the three animal feed by-products was determined according to Wood ham (2) by using one day old Dokki-4 chicks. Radiation induced an insignificant effect on the chemical constituent of meals. Also, the same trend was observed with TPE of both fish and meat meals. However, irradiation treatments improved TPE values of irradiated blood meal samples. From the results, it could be concluded that irradiation of animal feed by-products up to a dose level of 50 Gy has no adverse effects on the nutritional value of animal feed by-products

  10. Comparative evaluation of tensile strength of Gutta-percha cones with a herbal disinfectant.

    Science.gov (United States)

    Mahali, Raghunandhan Raju; Dola, Binoy; Tanikonda, Rambabu; Peddireddi, Suresh

    2015-01-01

    To evaluate and compare the tensile strength values and influence of taper on the tensile strength of Gutta-percha (GP) cones after disinfection with sodium hypochlorite (SH) and Aloe vera gel (AV). Sixty GP cones of size 110, 2% taper, 60 GP cones F3 ProTaper, and 60 GP of size 30, 6% taper were obtained from sealed packs as three different groups. Experimental groups were disinfected with 5.25% SH and 90% AV gel except the control group. Tensile strengths of GP were measured using the universal testing machine. The mean tensile strength values for Group IA, IIA and IIIA are 11.8 MPa, 8.69 MPa, and 9.24 MPa, respectively. Results were subjected to statistical analysis one-way analysis of variance test and Tukey post-hoc test. 5.25% SH solutions decreased the tensile strength of GP cones whereas with 90% AV gel it was not significantly altered. Ninety percent Aloe vera gel as a disinfectant does not alter the tensile strength of GP cones.

  11. Enhanced photocatalytic disinfection of indoor air

    Energy Technology Data Exchange (ETDEWEB)

    Vohra, Amit; Goswami, D.Y.; Deshpande, D.A.; Block, S.S. [Solar Energy and Energy Conversion Laboratory, Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, FL 32611 (United States)

    2006-04-18

    A silver ion doped TiO{sub 2} based photocatalyst, with improved destruction of airborne microbes, has been developed. The performance of the silver ion doped photocatalyst is demonstrated using a catalyst coated filter in a recirculating air experimental facility. Bacillus cereus, Staphylococcus aureus, Escherichia coli, Aspergillus niger, and MS2 Bacteriophage have been used as indexes to demonstrate the high disinfection efficiency of the enhanced photocatalysis process. The microbial destruction performance of the enhanced photocatalyst is found to be an order of magnitude higher than that of a conventional TiO{sub 2} photocatalyst. The process of enhanced photocatalysis can thus be used effectively against high concentrations of airborne microorganisms, making it an attractive option as a defense against bio-terrorism. (author)

  12. Antimicrobial-Coated Granules for Disinfecting Water

    Science.gov (United States)

    Akse, James R.; Holtsnider, John T.; Kliestik, Helen

    2011-01-01

    Methods of preparing antimicrobialcoated granules for disinfecting flowing potable water have been developed. Like the methods reported in the immediately preceding article, these methods involve chemical preparation of substrate surfaces (in this case, the surfaces of granules) to enable attachment of antimicrobial molecules to the surfaces via covalent bonds. A variety of granular materials have been coated with a variety of antimicrobial agents that include antibiotics, bacteriocins, enzymes, bactericides, and fungicides. When employed in packed beds in flowing water, these antimicrobial-coated granules have been proven effective against gram-positive bacteria, gram-negative bacteria, fungi, and viruses. Composite beds, consisting of multiple layers containing different granular antimicrobial media, have proven particularly effective against a broad spectrum of microorganisms. These media have also proven effective in enhancing or potentiating the biocidal effects of in-line iodinated resins and of very low levels of dissolved elemental iodine.

  13. Biological efficacy and toxic effect of emergency water disinfection process based on advanced oxidation technology.

    Science.gov (United States)

    Tian, Yiping; Yuan, Xiaoli; Xu, Shujing; Li, Rihong; Zhou, Xinying; Zhang, Zhitao

    2015-12-01

    An innovative and removable water treatment system consisted of strong electric field discharge and hydrodynamic cavitation based on advanced oxidation technologies was developed for reactive free radicals producing and waterborne pathogens eliminating in the present study. The biological efficacy and toxic effects of this advanced oxidation system were evaluated during water disinfection treatments. Bench tests were carried out with synthetic microbial-contaminated water, as well as source water in rainy season from a reservoir of Dalian city (Liaoning Province, China). Results showed that high inactivation efficiency of Escherichia coli (>5 log) could be obtained for synthetic contaminated water at a low concentration (0.5-0.7 mg L(-1)) of total oxidants in 3-10 s. The numbers of wild total bacteria (108 × 10(3) CFU mL(-1)) and total coliforms (260 × 10(2) MPN 100 mL(-1)) in source water greatly reduced to 50 and 0 CFU mL(-1) respectively after treated by the advanced oxidation system, which meet the microbiological standards of drinking water, and especially that the inactivation efficiency of total coliforms could reach 100%. Meanwhile, source water qualities were greatly improved during the disinfection processes. The values of UV254 in particular were significantly reduced (60-80%) by reactive free radicals. Moreover, the concentrations of possible disinfection by-products (formaldehyde and bromide) in treated water were lower than detection limits, indicating that there was no harmful effect on water after the treatments. These investigations are helpful for the ecotoxicological studies of advanced oxidation system in the treatments of chemical polluted water or waste water. The findings of this work suggest that the developed water treatment system is ideal in the acute phases of emergencies, which also could offer additional advantages over a wide range of applications in water pollution control.

  14. Effects of different cavity‑disinfectants and potassium titanyl ...

    African Journals Online (AJOL)

    disinfectants and potassium titanyl phosphate (KTP) laser on microtensile bond strength to primary dentin. Chlorhexidine (CHX), propolis (PRO), ozonated water (OW), gaseous ozone (OG) and KTP laser were used for this purpose. Methodology: ...

  15. Drinking water disinfection by means of ultraviolet radiation

    International Nuclear Information System (INIS)

    Gelzhaeuser, P.; Bewig, F.; Holm, K.; Kryschi, R.; Reich, G.; Steuer, W.

    1985-01-01

    The book presents all lectures held during a course at Technical Academy Esslingen, on September 10, 1985, on the subject of 'Drinking water disinfection by means of ultraviolet radiation'. The methods hitherto used for disinfection are no longer suitable because of the increasing amounts of organic pollutants found in the untreated water, and because of the necessity to make drinking water disinfection less expensive, non-polluting and thus environmentally compatible. U.V. irradiation is a method allowing technically simple and safe disinfection of the water, and also does not have any effect on the natural taste of the drinking water. The lectures presented discuss all aspects of the method, the equipment, and the performance of irradiation systems in practice. (orig./PW) [de

  16. Waterline ATS B. globigii spore water disinfection data

    Data.gov (United States)

    U.S. Environmental Protection Agency — Disinfection of B. globigii spores (a non-pathogenic surrogate for B. anthracis) in clean and dirty water using the ATS-Waterline system, which uses ultraviolet...

  17. Effect of ultrasonic pretreatment on purified water disinfection

    International Nuclear Information System (INIS)

    Simon Andreu, P.; Lardin Mifsut, C.; Vergara Romero, L.; Polo Canas, P. M.; Perez Sanchez, P.; Rancano Perez, A.

    2009-01-01

    Due to the importance of a suitable water disinfection in order to insure a pollutant effect minimization against environment, this work has been carried out to determine how can affect an ultrasonic pre-treatment upon disinfection step. It has been confirmed the ultrasonic disintegration of bacterial cells in treated water and disinfectant power of treatment by itself, which is not enough to be used as a single method in water disinfection. It has also been proved that from a technical and economical point of view the combination of UV and ultrasound improves the UV treatment performance. Finally, it has been detected that an ultrasonic pre-treatment increases chlorination effectiveness, however the high cost in this combination makes it unfeasible of industrial scale. (Author) 6 refs

  18. Effect of hydrodynamic cavitation on zooplankton: A tool for disinfection

    Digital Repository Service at National Institute of Oceanography (India)

    Sawant, S.S.; Anil, A.C.; Venkat, K.; Gaonkar, C.; Kolwalkar, J.; Khandeparker, L.; Desai, D.V.; Mahulkar, A.V.; Ranade, V.V.; Pandit, A.B.

    by individual oscillating cavity, cell wall strength and geometrical and operating parameters of cavitation device. Theoretical model for quantifying the cavitationally generated turbulent shear and extent of microbial disinfection has been developed...

  19. Assessment of apparent effectiveness of chemical egg disinfectants ...

    African Journals Online (AJOL)

    Aquaculture holds the potential to supplement catches as well as produce seed ... re-circulating incubation system at the National Aquaculture Center, Domasi, Malawi. ... Key words: Egg, disinfectants, incubation, recirculation, hatchability, egg ...

  20. development of an automated batch-process solar water disinfection

    African Journals Online (AJOL)

    user

    This work presents the development of an automated batch-process water disinfection system ... Locally sourced materials in addition to an Arduinomicro processor were used to control ..... As already mentioned in section 3.1.1, a statistical.

  1. IDENTIFICATION OF TI02/UV DISINFECTION BYPRODUCTS IN DRINKING WATER

    Science.gov (United States)

    Due to concern over the presence of trihalomethanes (THMs) and other chlorinated byproducts in chlorinated drinking water, alternative disinfection methods are being explored. One of the alternative treatment methods currently being evaluated for potential use with small systems ...

  2. Selecting a Sustainable Disinfection Technique for Wastewater Reuse Projects

    Directory of Open Access Journals (Sweden)

    Jorge Curiel-Esparza

    2014-09-01

    Full Text Available This paper presents an application of the Analytical Hierarchy Process (AHP by integrating a Delphi process for selecting the best sustainable disinfection technique for wastewater reuse projects. The proposed methodology provides project managers a tool to evaluate problems with multiple criteria and multiple alternatives which involve non-commeasurable decision criteria, with expert opinions playing a major role in the selection of these treatment technologies. Five disinfection techniques for wastewater reuse have been evaluated for each of the nine criteria weighted according to the opinions of consulted experts. Finally, the VIKOR method has been applied to determine a compromise solution, and to establish the stability of the results. Therefore, the expert system proposed to select the optimal disinfection alternative is a hybrid method combining the AHP with the Delphi method and the VIKOR technique, which is shown to be appropriate in realistic scenarios where multiple stakeholders are involved in the selection of a sustainable disinfection technique for wastewater reuse projects.

  3. Mimicking disinfection and drying of biofilms in contaminated endoscopes

    NARCIS (Netherlands)

    Kovaleva, J.; Degener, J. E.; van der Mei, H. C.

    2010-01-01

    The effects of peracetic acid-based (PAA) disinfectant with, and without, additional drying on Candida albicans, Candida parapsilosis, Pseudomonas aeruginosa and Stenotrophomonas maltophilia, isolated from contaminated flexible endoscopes, in single-and dual-species biofilms were studied. Biofilms

  4. Selection Criteria for Water Disinfection Techniques in Agricultural Practices

    OpenAIRE

    Haute, Sam van; Sampers, Imca; Jacxsens, Liesbeth; Uyttendaele, Mieke

    2013-01-01

    This paper comprises a selection tool for water disinfection methods for fresh produce pre- and postharvest practices. A variety of water disinfection technologies is available on the market and no single technology is the best choice for all applications. It can be difficult for end users to choose the technology that is best fit for a specific application. Therefore, the different technologies were characterized in order to identify criteria that influence the suitability of a technology fo...

  5. Methodological approaches to disinfection of human hepatitis B virus.

    OpenAIRE

    Prince, D L; Prince, H N; Thraenhart, O; Muchmore, E; Bonder, E; Pugh, J

    1993-01-01

    Three commercial disinfectants (two quaternary formulations and one phenolic) were tested against human hepatitis B virus (HHBV). The treated virus was assayed for infectivity by the chimpanzee assay and for morphological alteration by the Morphological Alteration and Disintegration Test. The same agents were tested against duck hepatitis B virus in a duck hepatocyte infectivity assay. It is apparent that human and duck hepatitis viruses were relatively susceptible to disinfection, becoming n...

  6. Composting of gamma-radiation disinfected sewage sludge

    International Nuclear Information System (INIS)

    Kawakami, W.; Hashimoto, S.; Watanabe, H.; Nishimura, K.; Watanabe, H.; Ito, H.; Takehisa, M.

    1981-01-01

    The composting of radiation disinfected sewage sludge has been studied since 1978, aiming to present a new process of sludge composting for agricultural uses. This process is composed of two steps: irradiation step to disinfect sludge, and composting step to remove odor and easily decomposable organics in sludge. In this paper, the gamma-irradiation effect on sludge cake and composting condition of irradiated sludge are discussed. (author)

  7. Influence of disinfectant solutions on the tensile bond strength of a fourth generation dentin bonding agent

    Directory of Open Access Journals (Sweden)

    BOCANGEL Jorge Saldivar

    2000-01-01

    Full Text Available The purpose of the present study was to evaluate the influence of different disinfectant solutions on the tensile bond strength of a fourth generation dentin bonding agent. Forty non carious human molars were selected. Teeth were embedded in acrylic resin and ground until the exposure of a flat superficial dentin surface. Teeth were randomly divided in 4 groups and treated as follows: Group 1 - 2.5% NaOCl for 40 seconds; Group 2 - 2% chlorhexidine for 40 seconds; Group 3 - 1.23% acidulated fluoride for 4 minutes; and Group 4 - control (without disinfectant solution. Following treatments, Scotchbond Multipurpose Plus® (3M was used according to the manufacturer's instructions. After that, the test specimens were built with composite resin (Z100®-3M, using a standard Teflon matrix. The specimens were stored in distilled water for 24 hours at a temperature of 37ºC. The tensile strength test was performed using a Mini Instrom testing machine. The mean values obtained for each group, in MPa, were: Group 1 - 7.37 (± 2.51; Group 2 - 11.25 (± 4.65; Group 3 - 9.80 (± 3.11; and Group 4 - 10.96 (± 3.37. The results were submitted to statistical analysis using the ANOVA test, and no statistical significant differences among the groups were found. It can be concluded that the different disinfectant substances used in this research do not adversely affect dentin adhesion.

  8. Data for comparison of chlorine dioxide and chlorine disinfection power in a real dairy wastewater effluent

    Directory of Open Access Journals (Sweden)

    Maliheh Akhlaghi

    2018-06-01

    Full Text Available Disinfection of water refers to a special operation that is doing to kill or disable causative organisms (i.e. Pathogens and in particular, intestinal bacteria. The aim of this pilot study is comparison of disinfection power of Chlorine dioxide and chlorine in a real dairy wastewater effluent. In this regard, firstly prepared two 220-l tanks made of polyethylene as reaction tanks and filled by effluent of a dairy wastewater treatment plant. Both tanks were equipped with mechanical stirrer. Then a Diaphragm dosing pumps with the maximum capacity of 3.9 l per hour were used for the chlorine dioxide and chlorine (Calcium hypochlorite 0.5 up to 3 ppm injection. Residual level of Chlorine dioxide and Chlorine were measured by portable photometric method DT4B kit, Germany. Finally, the Multiple-Tube Fermentation, Brilliant Green Bile Broth (BGB and Eosin methylene blue Agar (EMB technique was used for microbial analysis and the results were reported as the most probable number index (MPN respectively. The data showed that the residual of chlorine dioxide could stood more active than residual of chlorine in the aqueous environment significantly. Therefore, Use of chlorine dioxide is more effective than chlorine for removal fecal and total coliform from dairy wastewater effluent. Keywords: Disinfection, Chlorine dioxide, Chlorine, Total coliform, Fecal coliform

  9. A Review of Heterogeneous Photocatalysis for Water and Surface Disinfection

    Directory of Open Access Journals (Sweden)

    John Anthony Byrne

    2015-03-01

    Full Text Available Photo-excitation of certain semiconductors can lead to the production of reactive oxygen species that can inactivate microorganisms. The mechanisms involved are reviewed, along with two important applications. The first is the use of photocatalysis to enhance the solar disinfection of water. It is estimated that 750 million people do not have accessed to an improved source for drinking and many more rely on sources that are not safe. If one can utilize photocatalysis to enhance the solar disinfection of water and provide an inexpensive, simple method of water disinfection, then it could help reduce the risk of waterborne disease. The second application is the use of photocatalytic coatings to combat healthcare associated infections. Two challenges are considered, i.e., the use of photocatalytic coatings to give “self-disinfecting” surfaces to reduce the risk of transmission of infection via environmental surfaces, and the use of photocatalytic coatings for the decontamination and disinfection of medical devices. In the final section, the development of novel photocatalytic materials for use in disinfection applications is reviewed, taking account of materials, developed for other photocatalytic applications, but which may be transferable for disinfection purposes.

  10. Efficiency of hydrogen peroxide in improving disinfection of ICU rooms.

    Science.gov (United States)

    Blazejewski, Caroline; Wallet, Frédéric; Rouzé, Anahita; Le Guern, Rémi; Ponthieux, Sylvie; Salleron, Julia; Nseir, Saad

    2015-02-02

    The primary objective of this study was to determine the efficiency of hydrogen peroxide (H₂O₂) techniques in disinfection of ICU rooms contaminated with multidrug-resistant organisms (MDRO) after patient discharge. Secondary objectives included comparison of the efficiency of a vaporizator (HPV, Bioquell) and an aerosolizer using H₂O₂, and peracetic acid (aHPP, Anios) in MDRO environmental disinfection, and assessment of toxicity of these techniques. This prospective cross-over study was conducted in five medical and surgical ICUs located in one University hospital, during a 12-week period. Routine terminal cleaning was followed by H₂O₂ disinfection. A total of 24 environmental bacteriological samplings were collected per room, from eight frequently touched surfaces, at three time-points: after patient discharge (T0), after terminal cleaning (T1) and after H₂O₂ disinfection (T2). In total 182 rooms were studied, including 89 (49%) disinfected with aHPP and 93 (51%) with HPV. At T0, 15/182 (8%) rooms were contaminated with at least 1 MDRO (extended spectrum β-lactamase-producing Gram-negative bacilli 50%, imipenem resistant Acinetobacter baumannii 29%, methicillin-resistant Staphylococcus aureus 17%, and Pseudomonas aeruginosa resistant to ceftazidime or imipenem 4%). Routine terminal cleaning reduced environmental bacterial load (P disinfection efficiency.

  11. Organic chloramines in chlorine-based disinfected water systems: A critical review.

    Science.gov (United States)

    How, Zuo Tong; Kristiana, Ina; Busetti, Francesco; Linge, Kathryn L; Joll, Cynthia A

    2017-08-01

    This paper is a critical review of current knowledge of organic chloramines in water systems, including their formation, stability, toxicity, analytical methods for detection, and their impact on drinking water treatment and quality. The term organic chloramines may refer to any halogenated organic compounds measured as part of combined chlorine (the difference between the measured free and total chlorine concentrations), and may include N-chloramines, N-chloramino acids, N-chloraldimines and N-chloramides. Organic chloramines can form when dissolved organic nitrogen or dissolved organic carbon react with either free chlorine or inorganic chloramines. They are potentially harmful to humans and may exist as an intermediate for other disinfection by-products. However, little information is available on the formation or occurrence of organic chloramines in water due to a number of challenges. One of the biggest challenges for the identification and quantification of organic chloramines in water systems is the lack of appropriate analytical methods. In addition, many of the organic chloramines that form during disinfection are unstable, which results in difficulties in sampling and detection. To date research has focussed on the study of organic monochloramines. However, given that breakpoint chlorination is commonly undertaken in water treatment systems, the formation of organic dichloramines should also be considered. Organic chloramines can be formed from many different precursors and pathways. Therefore, studying the occurrence of their precursors in water systems would enable better prediction and management of their formation. Copyright © 2017. Published by Elsevier B.V.

  12. Hazard assessment of three haloacetic acids, as byproducts of water disinfection, in human urothelial cells.

    Science.gov (United States)

    Marsà, Alicia; Cortés, Constanza; Hernández, Alba; Marcos, Ricard

    2018-04-07

    Disinfection by-products (DBPs) are compounds produced in the raw water disinfection processes. Although increased cancer incidence has been associated with exposure to this complex mixture, the carcinogenic potential of individual DBPs remains not well known; thus, further studies are required. Haloacetic acids (HAAs) constitute an important group among DBPs. In this study, we have assessed the in vitro carcinogenic potential of three HAAs namely chloro-, bromo-, and iodoacetic acids. Using a long-term (8 weeks) and sub-toxic doses exposure scenario, different in vitro transformation markers were evaluated using a human urothelial cell line (T24). Our results indicate that long-term exposure to low doses of HAAs did not reproduce the genotoxic effects observed in acute treatments, where oxidative DNA damage was induced. No changes in the transformation endpoints analyzed were observed, as implied by the absence of significant morphological, cell growth rate and anchorage-independent cell growth pattern modifications. Interestingly, HAA-long-term exposed cells developed resistance to oxidative stress damage, what would explain the observed differences between acute and long-term exposure conditions. Accordingly, data obtained under long-term exposure to sub-toxic doses of HAAs could be more accurate, in terms of risk assessment, than under acute exposure scenarios. Copyright © 2018. Published by Elsevier Inc.

  13. [Water disinfection by the combined exposure to super-high frequency energy and available chlorine produced during water electrolysis].

    Science.gov (United States)

    Klimarev, S I; Siniak, Iu E

    2014-01-01

    The article reports the results of studying the effects on polluted water of SHF-energy together with the residual free (active) chlorine as a by-product of electrolysis action on dissolved chlorine-containing salts. Purpose of the studies was to evaluate input of these elements to the water disinfection effect. The synergy was found to kill microorganisms without impacts on the physicochemical properties of processed water or nutrient medium; therefore, it can be used for water treatment, and cultivation of microorganisms in microbiology.

  14. Peracetic acid as disinfectant of municipal wastewaters; L'acido peracetico nella disinfezione dei reflui urbani

    Energy Technology Data Exchange (ETDEWEB)

    Funari, E. [Istituto Superiore di Sanita' , Laboratorio di Igiene Ambientale, Reparto di Medicina Ambientale, Rome (Italy); Lopez, A. [Consiglio Nazionale delle Ricerche, Istituto di Ricerca sulle Acque, Reparto di Chimica e Tecnologia delle Acque, Bari (Italy)

    2000-09-01

    Based on the currently available literature, this paper is aimed at providing a sort of the <> on the use of peracetic acid (C{sub 3}COOOH{identical_to} Paa) as disinfectant of biologically treated municipal wastewater: the growing interest for this substance, used since many years in other sectors (e.g., food-industry, breweries, etc.) is mainly due to the claimed limited formation, if any, of harmful disinfecting by-products (Dbp) with consequent lack of toxicity in Paa treated wastewaters. Such features are just the opposite of those of chlorine, i.e. the most used disinfectant for municipal wastewater. During chlorine-disinfecting, in fact, numerous harmful organo-chlorinated Dbp are formed and, accordingly, the toxicity of chlorinated effluents results very high. In spite of the above reported <> properties of Paa, its use at large scale facilities is still restricted and this not only because of its costs but even for the limited knowledge concerning: the actual disinfecting effectiveness towards different pathogens, the nature and the toxicological properties of its potential Dbp, and the disinfecting performances at large scale facilities. The present paper, besides reporting an extensive and useful collection of references concerning Paa, provides a critical review on the current knowledge regarding specific Paa features such as: its disinfecting effectiveness towards different pathogenic micro-organisms, the nature and the toxicity of its disinfecting by-products, the environmental impact of Paa treated effluents, and the operative conditions used at large scale wastewater treatment plants. [Italian] Il presente lavoro, basandosi sui dati disponibili in letteratura, si propone di fare il punto sull'impiego dell'acido peracetico (CH{sub 3}COOOH{identical_to} PAA) come disinfettante di reflui urbani depurati. Il crescente interesse nei confronti di questa sostenza, gia' nota come disinfettante in

  15. Radiation disinfection of sewage sludge and composting of the irradiated sludge

    International Nuclear Information System (INIS)

    Hashimoto, Shoji; Nishimura, Koichi; Watanabe, Hiromasa; Kawakami, Waichiro

    1985-01-01

    In the radiation disinfected sewage sludge, its stabilization is necessary with the composting. In this disinfected sludge, there is no need of keeping it at high temperature at the cost of fermentation velocity. The fermentation velocity can thus be set to obtain its maximum value. In sewage sludge utilization of farm land, to prevent the contamination with pathogenic bacteria and the secondary pollution, the radiation disinfection of dehydrated sludge and the composting of the disinfected sludge have been studied. The disinfection effect when an electron accelerator is used for the radiation source is described. Then, the composting of the disinfected sludge is described in chemical kinetics of the microorganisms. (Mori, K.)

  16. Theoretical model for the UV disinfection system in the operating ward of PZU 'Filip Vtori'

    International Nuclear Information System (INIS)

    Ilkov, Marjan

    2010-01-01

    Here we investigate the theoretical modeling of an UV disinfection system for the operating ward in PZU 'FILIP VTORI'. As nocosomial infections pose a serious threat to patients everywhere in the world, here the disinfection of the air and the surfaces is modeled and discussed. The surfaces are disinfected with direct illumination of open UV after hours system, UV curtains, overhead disinfection, floor disinfection and disinfection of the incoming air through the ventilation/air-condition system. From the results it can be seen that the concentrations of bacteria, fungi and viruses drop significantly which in turn should give a significant drop in a number of hospital acquired infections.(Author)

  17. In vitro study on the disinfectability of two split-septum needle-free connection devices using different disinfection procedures

    Directory of Open Access Journals (Sweden)

    Engelhart, Steffen

    2015-12-01

    Full Text Available This in vitro study investigated the external disinfection of two needle-free connection devices (NFC using Octeniderm (spraying and wiping technique vs. Descoderm pads (wiping technique. The split-septum membrane of the NFC was contaminated with >10 CFU . The efficacy of the disinfection at 30 sec. exposure time was controlled by taking a swab sample and by flushing the NFC with sterile 0.9% sodium chloride solution. Disinfection with octenidine dihydrochloride 0.1 g, 1-Propanol 30.0 g, and 2-Propanol 45.0 g in solution was highly effective (CFU reduction ≥4 log against both microorganisms, whereas the use of 63.1 g 2-Propanol in 100 ml solution led to residual contamination with . Our investigation underlines that (i in clinical practice disinfection of NFCs before use is mandatory, and that (ii details of disinfection technique are of utmost importance regarding their efficacy. Our investigation revealed no significant differences between both split-septum NFC types. Clinical studies are needed to confirm a possible superiority of disinfectants with long-lasting residual antimicrobial activity.

  18. Effect of different types of disinfection solution and aging on the hardness and colour stability of maxillofacial silicone elastomers.

    Science.gov (United States)

    Cevik, Pinar; Yildirim-Bicer, Arzu Z

    2017-11-09

    Understanding the effect of aging and different disinfecting agents on the physical properties of pigmented maxillofacial silicones may help eliminate the current uncertainty as to the best follow-up suggestions for the patients treated with silicone prostheses. One hundred fifty specimens (14 × 2 mm) were evaluated for colour and 75 specimens (30 × 10 mm) for hardness (total, 225 specimens). Five specimens were used for hardness testing in each disinfecting solution while 10 silicone specimens were used for colour evaluation. The samples were separated into 5 groups and the initial hardness and colour evaluations were performed and placed in disinfectant solution (neutral soap, effervescent tablet, 0.2% chlorhexidine, 4% chlorhexidine, sodium hypochlorite). A second set of colour and hardness measurements was taken after 48 hours of disinfection and 1,008 hours of artificial aging in a QUV-accelerated weathering tester. Two-way and 1-way analysis of variance with Tukey tests and paired t-test were used for statistical analysis (α = 0.05). Before artificial aging, the hardness value of the red pigment group was found to be significantly lower than that of the brown pigment group. After aging, the lowest Shore A value was seen in the neutral soap group, while the highest was seen in the effervescent tablet. Based on the results of this study, chlorohexidine 0.2% was found to be most suitable agent for disinfection of the prostheses. Washing with neutral soap caused loss of pigment from the surface of the silicones. Sodium hypochlorite was found to have a colour-fading effect on silicone specimens.

  19. Effect of peracetic acid, ultraviolet radiation, nanofiltration-chlorine in the disinfection of a non conventional source of water (Tula Valley).

    Science.gov (United States)

    Trujillo, J; Barrios, J A; Jimenez, B

    2008-01-01

    Water supply for human consumption requires certain quality that reduces health risks to consumers. In this sense, the process of disinfection plays an important role in the elimination of pathogenic microorganisms. Even though chlorination is the most applied process based on its effectiveness and cost, its application is being questioned considering the formation of disinfection by-products (DBPs). Therefore, alternative disinfectants are being evaluated and some treatment processes have been proposed to remove DBPs precursors (organic matter. This paper reports the results of disinfection of a non conventional source of water (aquifer recharged unintentionally with raw wastewater) with peracetic acid (PAA) and ultraviolet radiation (UV) as well as nanofiltration (NF) followed by chlorination to produce safe drinking water. The results showed that a dose of 2 mg/L PAA was needed to eliminate total and faecal coliforms. For UV light, a dose of 12.40 mWs/cm2 reduced total and faecal coliforms below the detection limit. On the other hand, chlorine demand of water before NF was 1.1-1.3 mg/L with a trihalomethane formation potential (THMFP) of 118.62 microg/L, in contrast with chlorination after NF where the demand was 0.5 mg/L and THMFP of 17.64 microg/L. The recommended scheme is nanofiltration + chlorination.

  20. Visible light photocatalytic disinfection of E. coli with TiO_2–graphene nanocomposite sensitized with tetrakis(4-carboxyphenyl)porphyrin

    International Nuclear Information System (INIS)

    Rahimi, Rahmatollah; Zargari, Solmaz; Yousefi, Azam; Yaghoubi Berijani, Marzieh; Ghaffarinejad, Ali; Morsali, Ali

    2015-01-01

    Graphical abstract: TiO_2–graphene nanocomposites with different content of graphene were synthesized via a facile one-step solvothermal method. Photoelectrochemical responses of prepared photocatalysts were measured to determine the optimum content of graphene in TG nanocomposites. The results show that the TG nanocomposite with 3% of graphene has the highest photoactivity. This compound was sensitized with tetrakis(4-carboxyphenyl)porphyrin (TGP). The prepared photocatalysts were used for photocatalytic disinfection of E. coli. The results showed that the photocatalytic disinfection of the TG nanocomposite was increased after sensitization with porphyrin. The enhanced photocatalytic performance could be attributed to the synergistic effect between TiO_2, graphene and porphyrin sensitizer in the TGP photocatalyst. - Highlights: • TiO_2–graphene nanocomposites (TG) were synthesized with different content of graphene. • The TG nanocomposite with different content of graphene was sensitized with porphyrin (TGP). • The disinfection of E. coli using TGP was investigated in the visible light. • Porphyrin sensitizer increases effectively the photocatalytic disinfection efficiency of TGP. - Abstract: The present research deals with the development of a new heterogeneous photocatalysis system for disinfection of bacteria from wastewater by using TiO_2–graphene (TG) nanocomposite sensitized with tetrakis(4-carboxyphenyl)porphyrin (TCPP). The disinfection of wastewater using this photocatalyst is not reported in the literature yet. All the synthesized materials were thoroughly characterized by Raman, XRD, DRS, BET, and SEM analysis. The optimum content of graphene in the TiO_2–graphene nanocomposite was determined by photocurrent responses of prepared photocatalysts. Subsequently, the photocurrent measurements demonstrate that the TiO_2–graphene nanocomposite with 3% graphene content has higher photoactivity. Furthermore, sensitization of the TiO_2

  1. Overcoming the problem of residual microbial contamination in dental suction units left by conventional disinfection using novel single component suction handpieces in combination with automated flood disinfection.

    Science.gov (United States)

    Boyle, M A; O'Donnell, M J; Russell, R J; Galvin, N; Swan, J; Coleman, D C

    2015-10-01

    Decontaminating dental chair unit (DCU) suction systems in a convenient, safe and effective manner is problematic. This study aimed to identify and quantify the extent of the problems using 25 DCUs, methodically eliminate these problems and develop an efficient approach for reliable, effective, automated disinfection. DCU suction system residual contamination by environmental and human-derived bacteria was evaluated by microbiological culture following standard aspiration disinfection with a quaternary ammonium disinfectant or alternatively, a novel flooding approach to disinfection. Disinfection of multicomponent suction handpieces, assembled and disassembled, was also studied. A prototype manual and a novel automated Suction Tube Cleaning System (STCS) were developed and tested, as were novel single component suction handpieces. Standard aspiration disinfection consistently failed to decontaminate DCU suction systems effectively. Semi-confluent bacterial growth (101-500 colony forming units (CFU) per culture plate) was recovered from up to 60% of suction filter housings and from up to 19% of high and 37% of low volume suction hoses. Manual and automated flood disinfection of DCU suction systems reduced this dramatically (ranges for filter cage and high and low volume hoses of 0-22, 0-16 and 0-14CFU/plate, respectively) (P<0.0001). Multicomponent suction handpieces could not be adequately disinfected without prior removal and disassembly. Novel single component handpieces, allowed their effective disinfection in situ using the STCS, which virtually eliminated contamination from the entire suction system. Flood disinfection of DCU suction systems and single component handpieces radically improves disinfection efficacy and considerably reduces potential cross-infection and cross-contamination risks. DCU suction systems become heavily contaminated during use. Conventional disinfection does not adequately control this. Furthermore, multicomponent suction handpieces

  2. Occurrence of nitrogenous and carbonaceous disinfection byproducts in drinking water distributed in Shenzhen, China.

    Science.gov (United States)

    Huang, Huang; Zhu, Haihui; Gan, Wenhui; Chen, Xue; Yang, Xin

    2017-12-01

    A 12-month sampling program was conducted throughout a drinking water distribution system in Shenzhen and the data from 251 samples provide a comprehensive picture of the spatial and seasonal variability of 17 species disinfection by-products (DBPs) in a city with subtropical monsoon climate. The carbonaceous disinfection by-product (C-DBPs) included four trihalomethanes (THMs), three trihaloacetaldehydes (THAs) and two haloketones (HKs). Their median concentrations over the entire period were 19.9 μg/L, 3.4 μg/L and 1.4 μg/L, respectively. The nitrogenous DBPs (N-DBPs) monitored were four haloacetonitriles (HANs) and four haloacetamides (HAcAms). Their median levels were 2.0 μg/L and 1.5 μg/L, respectively. Low levels of brominated DBP species (bromine substitution factors ≤ 0.5) were observed. The BSF of each DBP class followed the trend: THMs ≈ DHAcAms > DHANs > THAs. All the DBP concentrations showed clear seasonal variations with the highest average concentrations in spring. Correlation analyses showed that the THMs and CH levels in Shenzhen drinking water could be used as statistical indicators of the levels of unregulated N-DBPs (0.4 water in China, and provide an important reference data set for DBP occurrence in cities with a subtropical monsoon climate around the world. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Enhanced composting of radiation disinfected sewage sludge

    International Nuclear Information System (INIS)

    Kawakami, W.; Hashimoto, S.

    1984-01-01

    Studies on isothermal composting of radiation disinfected sewage sludge and liquid chromatography of water extracts of the products were carried out. The optimum temperature and pH were around 50 deg C and 7 to 8, respectively. The repeated use of products as seeds increased the rate of CO 2 evolution. The rate reached a maximum within 10 hours and decreased rapidly, and the CO 2 evolution ceased after about 3 days. The conversion of organic carbon to carbon dioxide attained to about 40% for the repeated use of products as seeds at the optimum conditions. As long as seeds as available were used, no remarkable difference was found in the composting of unirradiated and irradiated sludges. The composting process using radiation, however, can be carried out at the optimum conditions and is expected to shorten the composting period, because it is not necessary to keep fermentation temperature higher to reduce pathogen in sludge. Liquid chromatographic studies of the products showed that low molecular components decreased and higher molecular ones increased with fermentation. An index expressing the degree of reduction of easily decomposable organics was presented. The index also showed that the optimum temperature for fermentation was 50 deg C. (author)

  4. Electron beam disinfection of sewage sludge

    International Nuclear Information System (INIS)

    Hashimoto, Shoji

    1992-01-01

    Electron beam treatment of dehydrated sewage sludge for safe reutilization was performed. Ranges of total bacterial counts and total coliforms in the sludge were from 1.5 x 10 8 to 1.6 x 10 9 and from 2.2 x 10 7 to 1.5 x 10 8 per wet gram, respectively. Total bacterial counts decreased about 5 log cycles after irradiating 5 kGy and irradiation with 2 kGy was enough to kill all coliforms in sewage sludge. The survival curves of total bacteria, obtained by irradiation in oxygen atmosphere, approached to that in nitrogen atmosphere with the increase of sludge thickness. No effects of dose rate and electron energy were found when the sludge layers were thin enough. Continuous disinfection of sewage sludge cake, with the maximum feed rate of 300 kg-sludge/hr, was successfully performed with a Cockcroft-Walton type electron accelerator, a sludge pump and a flat nozzle. (J.P.N.)

  5. Designing plasmas for chronic wound disinfection

    International Nuclear Information System (INIS)

    Nosenko, T; Shimizu, T; Morfill, G E

    2009-01-01

    Irradiation with low-temperature atmospheric-pressure plasma provides a promising method for chronic wound disinfection. To be efficient for this purpose, plasma should meet the following criteria: it should significantly reduce bacterial density in the wounded area, cause a long-term post-irradiation inhibition of bacterial growth, yet without causing any negative effect on human cells. In order to design plasmas that would satisfy these requirements, we assessed the relative contribution of different components with respect to bactericidal properties due to irradiation with argon plasma. We demonstrate that plasma-generated UV radiation is the main short-term sterilizing factor of argon plasma. On the other hand, plasma-generated reactive nitrogen species (RNS) and reactive oxygen species (ROS) cause a long-term 'after-irradiation' inhibition of bacterial growth and, therefore, are important for preventing wound recolonization with bacteria between two treatments. We also demonstrate that at certain concentrations plasma-generated RNS and ROS cause significant reduction of bacterial density, but have no adverse effect on human skin cells. Possible mechanisms of the different effects of plasma-generated reactive species on bacteria and human cells are discussed. The results of this study suggest that argon plasma for therapeutic purposes should be optimized in the direction of reducing the intensity of plasma-generated UV radiation and increasing the density of non-UV plasma products.

  6. Designing plasmas for chronic wound disinfection

    Energy Technology Data Exchange (ETDEWEB)

    Nosenko, T; Shimizu, T; Morfill, G E [Max-Planck Institute for Extraterrestrial Physics, Garching (Germany)], E-mail: tnosenko@mpe.mpg.de

    2009-11-15

    Irradiation with low-temperature atmospheric-pressure plasma provides a promising method for chronic wound disinfection. To be efficient for this purpose, plasma should meet the following criteria: it should significantly reduce bacterial density in the wounded area, cause a long-term post-irradiation inhibition of bacterial growth, yet without causing any negative effect on human cells. In order to design plasmas that would satisfy these requirements, we assessed the relative contribution of different components with respect to bactericidal properties due to irradiation with argon plasma. We demonstrate that plasma-generated UV radiation is the main short-term sterilizing factor of argon plasma. On the other hand, plasma-generated reactive nitrogen species (RNS) and reactive oxygen species (ROS) cause a long-term 'after-irradiation' inhibition of bacterial growth and, therefore, are important for preventing wound recolonization with bacteria between two treatments. We also demonstrate that at certain concentrations plasma-generated RNS and ROS cause significant reduction of bacterial density, but have no adverse effect on human skin cells. Possible mechanisms of the different effects of plasma-generated reactive species on bacteria and human cells are discussed. The results of this study suggest that argon plasma for therapeutic purposes should be optimized in the direction of reducing the intensity of plasma-generated UV radiation and increasing the density of non-UV plasma products.

  7. Sterilization and disinfection: the prevailing indifference

    International Nuclear Information System (INIS)

    Mirza, I.

    2007-01-01

    To evaluate the knowledge and attitude of health care professionals towards the process of sterilization and disinfection, and to check the adequacy of the reading material accessible to them. The study comprised of three components. In the first part, sections devoted to this subject in the popular books read by the students of operation theatre assistant course and students of diploma in general nursing were examined for adequacy and authenticity of information. In the second part, standard operating procedures were examined regarding sterilization of textile, rubber tubes of suction units and diathermy hand pieces of 20 operation theatres of three teaching hospital attached to undergraduate medical college of Punjab. In the third part of the study, working knowledge of 64 practicing operation theatre assistants and 57 practicing nurses was assessed through a questionnaire. It was found that popular books either did not contain the required information or the information provided was misleading or incorrect. Standard operating procedures for sterilization of selected items of all the operation theatres studied fell much below the standard of practice desired in the light of current knowledge and contemporary practices. Finally the working knowledge of the professionals studied was much below the bare minimum expected by the profession. There is a dire need for upgrading the knowledge and attitude of health care professionals regarding sterilization, besides improving the operation theatres sterilization procedures. (author)

  8. Portable Ultraviolet Light Surface-Disinfecting Devices for Prevention of Hospital-Acquired Infections: A Health Technology Assessment

    Science.gov (United States)

    Nikitovic-Jokic, Milica; Kabali, Conrad; Li, Chunmei; Higgins, Caroline

    2018-01-01

    Background Hospital-acquired infections (HAIs) are infections that patients contract while in the hospital that were neither present nor developing at the time of admission. In Canada an estimated 10% of adults with short-term hospitalization have HAIs. According to 2003 Canadian data, between 4% and 6% of these patients die from these infections. The most common HAIs in Ontario are caused by Clostridium difficile. The standard method of reducing and preventing these infections is decontamination of patient rooms through manual cleaning and disinfection. Several portable no-touch ultraviolet (UV) light systems have been proposed to supplement current hospital cleaning and disinfecting practices. Methods We searched for studies published from inception of UV disinfection technology to January 23, 2017. We compared portable UV surface-disinfecting devices used together with standard hospital room cleaning and disinfecting versus standard hospital cleaning and disinfecting alone. The primary outcome was HAI from C. difficile. Other outcomes were combined HAIs, colonization (i.e., carrying an infectious agent without exhibiting disease symptoms), and the HAI-associated mortality rate. We used Grading of Recommendations Assessment, Development, and Evaluation (GRADE) to rate the quality of evidence of included studies. We also performed a 5-year budget impact analysis from the hospital's perspective. This assessment was limited to portable devices and did not examine wall mounted devices, which are used in some hospitals. Results The database search for the clinical review yielded 10 peer-reviewed publications that met eligibility criteria. Three studies focused on mercury UV-C–based technology, seven on pulsed xenon UV technology. Findings were either inconsistent or produced very low-quality evidence using the GRADE rating system. The intervention was effective in reducing the rate of the composite outcome of HAIs (combined) and colonization (but quality of evidence

  9. The Occurrence and Comparative Toxicity of Haloacetaldehyde Disinfection Byproducts in Drinking Water

    Science.gov (United States)

    The introduction of drinking water disinfection greatly reduced the incidence of waterborne diseases. However, the reaction between disinfectants and natural organic matter in the source water can lead to an unintended consequence, which is the formation of drinking water disinfe...

  10. Disinfection of stabilization pond effluent by peracetic acid and sodium hypochlorite

    Directory of Open Access Journals (Sweden)

    Negar Rezania

    2013-01-01

    Conclusions: The study demonstrated that application of combined PAA and NaOCl in disinfecting the effluent of the stabilization pond will promote the efficiency of disinfection process in inactivating the coliform group bacteria and fecal streptococci.

  11. Residual viral and bacterial contamination of surfaces after cleaning and disinfection

    NARCIS (Netherlands)

    Tuladhar, E.; Hazeleger, W.C.; Koopmans, M.; Zwietering, M.H.; Beumer, R.R.; Duizer, E.

    2012-01-01

    Environmental surfaces contaminated with pathogens can be sources of indirect transmission, and cleaning and disinfection are common interventions focused on reducing contamination levels. We determined the efficacy of cleaning and disinfection procedures for reducing contamination by noroviruses,

  12. Efficiency of a semiconductor diode laser in disinfection of the root canal system in endodontics: An in vitro study

    Directory of Open Access Journals (Sweden)

    Mithra N Hegde

    2015-01-01

    Full Text Available Context: The success of endodontic treatment depends on the eradication of microbes from the rootcanal system and prevention of reinfection. The root canal is shaped with hand and rotary instruments under constant irrigation to remove the inflamed and necrotic tissue, microbes/biofilms, and other debris from the root canal space. The main goal of instrumentation is to facilitate effective irrigation, disinfection, and filling. Throughout the history of endodontics, endeavors have continuously been made to develop more effective irrigant delivery and agitation systems for root canal irrigation. Aim: The purpose of this study was to evaluate the efficacy of three different newer irrigation delivery techniques; namely Endovac, Stropko Irrigator, and laser disinfection with 5.25% sodium hypochlorite. Materials and Methods: Forty teeth after disinfection by Occupational Safety and Health Administration (OSHA regulations were instrumented and inoculated with bacterial strains of Enterococcusfaecalis. The teeth were divided into four groups, in the experimental group, the irrigants were delivered with the Endovac, Stropko Irrigator, and laser irradiation and the control group which received no irrigation. The samples were incubated in Muller-Hilton media plates and incubated for 24 h. Statistical analysis used: The colony forming units were determined and statistically analyzed using the chi-square test. Results: According to the results obtained, laser irradiation resulted in complete disinfection of the root canal system. The Endovac system resulted in significant disinfection as compared to the Stropko Irrigator system. Conclusion: Laser irradiation resulted in significantly higher antimicrobial effects compared with the Endovac and Stropko irrigation groups when in conjunction with sodium hypochlorite

  13. Selection criteria for water disinfection techniques in agricultural practices.

    Science.gov (United States)

    Haute, Sam van; Sampers, Imca; Jacxsens, Liesbeth; Uyttendaele, Mieke

    2015-01-01

    This paper comprises a selection tool for water disinfection methods for fresh produce pre- and postharvest practices. A variety of water disinfection technologies is available on the market and no single technology is the best choice for all applications. It can be difficult for end users to choose the technology that is best fit for a specific application. Therefore, the different technologies were characterized in order to identify criteria that influence the suitability of a technology for pre- or postharvest applications. Introduced criteria were divided into three principal components: (i) criteria related to the technology and which relate to the disinfection efficiency, (ii) attention points for the management and proper operation, and (iii) necessities in order to sustain the operation with respect to the environment. The selection criteria may help the end user of the water disinfection technology to obtain a systematic insight into all relevant aspects to be considered for preliminary decision making on which technologies should be put to feasibility testing for water disinfection in pre- and postharvest practices of the fresh produce chain.

  14. Microbiological evaluation of ultrasonic nebulization for disinfecting dental impressions.

    Science.gov (United States)

    Mendonca, Marcio Jose; Rafael, Renata Santos; Camilotti, Veridiana; Menolli, Rafael Andrade; Sicoli, Eliseu Augusto; Teixeira, Nancielli; Sinhoreti, Mario Alexandre Coelho

    2013-07-01

    Disinfecting dental impressions is necessary to decrease the risk of cross-contamination in dental offices. Ultrasonic nebulization has been mentioned as a microbicidal technique that can be used to disinfect contaminated dental impressions. This study compared the microbicidal effect of 2% glutaraldehyde and 0.2% peracetic acid for the disinfection of dental impressions made with vinyl polysiloxane, using 2 disinfection methods: immersion and ultrasonic nebulization. Bactericial efficacy was examined using Staphylococcus aureus and Bacillus atrophaeus as indicators. Thirty impressions were obtained and distributed randomly in 5 groups (n = 6). Group 1 was immersed in 2% glutaraldehyde immersion for 10 minutes, Group 2 was immersed in 0.2% peracetic acid for 10 minutes, Group 3 underwent ultrasonic nebulization for 10 minutes in 2% glutaraldehyde solution, Group 4 underwent ultrasonic nebulization for 10 minutes in 0.2% peracetic acid solution, and Group 5 was a control group that received no disinfectant. Both solutions experienced a 100% reduction in microorganisms following ultrasonic nebulization, as did peracetic acid following immersion; however, immersion in glutaraldehyde demonstrated lower values of reduction in B atrophaeus group, with a statistically significant difference compared with the other experimental groups.

  15. Ultraviolet (UV) disinfection of grey water: particle size effects.

    Science.gov (United States)

    Winward, G P; Avery, L M; Stephenson, T; Jefferson, B

    2008-02-01

    The impact of water quality on the ultraviolet (UV) disinfection of grey water was investigated with reference to urban water reuse. Direct UV disinfection of grey water did not meet the stringent California State Title 22 criteria for unrestricted urban water reuse due to the presence of particulate material ranging from or = 2000 microm in size. Grey water was manipulated by settling to produce fractions of varying particle size distributions and blending was employed post-disinfection to extract particle-associated coliforms (PACs). The efficacy of UV disinfection was found to be linked to the particle size of the grey water fractions. The larger particle size fractions with a mean particle size of 262 microm and above were observed to shield more coliforms from UV light than did the smaller particles with a mean particle size below 119 microm. Up to 70% of total coliforms in the larger particle size fractions were particle-associated following a UV dose (fluence) of 260 mJ.cm(-2) and would remain undetected by standard coliform enumeration techniques. Implications for urban water reuse are discussed and recommendations made for grey water treatment to ensure removal of particle-associated indicator bacteria and pathogens prior to UV disinfection.

  16. Fresh water disinfection by pulsed low electric field

    International Nuclear Information System (INIS)

    Zheng, C; Xu, Y; Liu, Z; Yan, K

    2013-01-01

    In this paper, we describe a pulsed low electric field process for water disinfection. Electric intensity of 0.6–1.7 kV cm −1 is applied. Experiments are performed with a 1.2 L axis-cylinder reactor. A bipolar pulsed power source with pulsed width of 25 μs and frequency of 100–3000 Hz is used. Water conductivity of 3–200 μs cm −1 is investigated, which can significantly affect pulsed voltage-current waveforms and injected energy. Energy per pulse rises with increased water conductivity. The initial E. Coli density and water conductivity are two major factors influencing the disinfection. No disinfection effect is performed with deionized water of 3 μs cm −1 . When water conductivity is 25 μs cm −1 and bacteria density is 10 4 –10 6 cfu ml −1 , significant disinfection effect is observed. More than 99% of the cells can be disinfected with an energy density of less than 70 J ml −1 , while water temperature is below 30 °C.

  17. [Decontamination of dental unit waterlines using disinfectants and filters].

    Science.gov (United States)

    Monarca, S; Garusi, G; Gigola, P; Spampinato, L; Zani, C; Sapelli, P L

    2002-10-01

    Bacterial contamination of the dental unit water system can become a health problem for patients, particularly if they are immunodepressed. The present study has had the purpose of evaluating the effectiveness of methods of chemical decontamination using different disinfectants (peracetic acid, hydrogen peroxide, silver salts, chloramine T, glutaraldehyde T4) and methods of physical decontamination using synthetic membranes for the filtration of water. A preliminary removal procedure of the biofilm present in the waterline has been followed in a dental unit prepared on purpose for the research; subsequently different 2-week long maintenance procedures were applied using disinfectants injected by a pump and finally the bacterial contamination of the water flowing from the waterline was evaluated. The physical decontamination was performed using 0.22 mm membrane filters, which have been installed also in another dental unit, and the filtered water was analyzed to detect bacterial contamination. The preliminary procedure of biofilm removal succeeded obtaining germ-free water. Among the disinfectants used for the maintenance of the water quality only glutaraldehyde T4 was able to reduce the bacterial contamination under the limit suggested by the ADA. The membrane filter system was not able to purify the water, but when a disinfectant (peracetic acid) was used in the last part of the waterline good results were obtained. At present no decontamination system of dental waterline is available, and glutaraldehyde T4 seems to be the best disinfectant only if integrated with periodic biofilm removal for the maintenance of the water quality.

  18. Effectiveness of Four Disinfectants against Ebola Virus on Different Materials

    Directory of Open Access Journals (Sweden)

    Sophie Smither

    2016-07-01

    Full Text Available The West Africa Ebola virus (EBOV outbreak has highlighted the need for effective disinfectants capable of reducing viral load in a range of sample types, equipment and settings. Although chlorine-based products are widely used, they can also be damaging to equipment or apparatus that needs continuous use such as aircraft use for transportation of infected people. Two aircraft cleaning solutions were assessed alongside two common laboratory disinfectants in a contact kill assay with EBOV on two aircraft relevant materials representative of a porous and non-porous surface. A decimal log reduction of viral titre of 4 is required for a disinfectant to be deemed effective and two of the disinfectants fulfilled this criteria under the conditions tested. One product, Ardrox 6092, was found to perform similarly to sodium hypochlorite, but as it does not have the corrosive properties of sodium hypochlorite, it could be an alternative disinfectant solution to be used for decontamination of EBOV on sensitive apparatus.

  19. UV disinfection for reuse applications in North America.

    Science.gov (United States)

    Sakamoto, G; Schwartzel, D; Tomowich, D

    2001-01-01

    In an effort to conserve and protect limited water resources, the States of Florida and California have actively promoted wastewater reclamation and have implemented comprehensive regulations covering a range of reuse applications. Florida has a semi-tropical climate with heavy summer rains that are lost due to run off and evaporation. Much of California is arid and suffers periodic droughts, low annual rainfall and depleted ground water supplies. The high population density combined with heavy irrigation demands has depleted ground water supplies resulting in salt-water intrusion. During the past decade, Florida reuse sites have increased dramatically from 118 to 444 plants representing a total flow capacity of 826 MGD. California presently has over 250 plants producing 1 BGD with a projected increase of 160 sites over the next 20 years. To prevent the transmission of waterborne diseases, disinfection of reclaimed water is controlled by stringent regulations. Many states regulate wastewater treatment processes, nutrient removal, final effluent quality and disinfection criteria based upon the specific reuse application. As a rule, the resulting effluents have low turbidity and suspended solids. For such effluents, UV technology can economically achieve the most stringent disinfection targets that are required by the States of California and Florida for restricted and unrestricted reuse. This paper compares UV disinfection for wastewater reuse sites in California and Florida and discusses the effect of effluent quality on UV disinfection.

  20. Cleaning, disinfection and sterilization of surface prion contamination.

    Science.gov (United States)

    McDonnell, G; Dehen, C; Perrin, A; Thomas, V; Igel-Egalon, A; Burke, P A; Deslys, J P; Comoy, E

    2013-12-01

    Prion contamination is a risk during device reprocessing, being difficult to remove and inactivate. Little is known of the combined effects of cleaning, disinfection and sterilization during a typical reprocessing cycle in clinical practice. To investigate the combination of cleaning, disinfection and/or sterilization on reducing the risk of surface prion contamination. In vivo test methods were used to study the impact of cleaning alone and cleaning combined with thermal disinfection and high- or low-temperature sterilization processes. A standardized test method, based on contamination of stainless steel wires with high titres of scrapie-infected brain homogenates, was used to determine infectivity reduction. Traditional chemical methods of surface decontamination against prions were confirmed to be effective, but extended steam sterilization was more variable. Steam sterilization alone reduced the risk of prion contamination under normal or extended exposure conditions, but did show significant variation. Thermal disinfection had no impact in these studies. Cleaning with certain defined formulations in combination with steam sterilization can be an effective prion decontamination process, in particular with alkaline formulations. Low-temperature, gaseous hydrogen peroxide sterilization was also confirmed to reduce infectivity in the presence and absence of cleaning. Prion decontamination is affected by the full reprocessing cycle used on contaminated surfaces. The correct use of defined cleaning, disinfection and sterilization methods as tested in this report in the scrapie infectivity assay can provide a standard precaution against prion contamination. Copyright © 2013 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

  1. Evaluation of 5 Cleaning and Disinfection Methods for Nets Used to Collect Zebrafish (Danio rerio)

    OpenAIRE

    Collymore, Chereen; Porelli, Gina; Lieggi, Christine; Lipman, Neil S

    2014-01-01

    Few standardized methods of cleaning and disinfecting equipment in zebrafish facilities have been published, even though the effectiveness of these procedures is vital to preventing the transmission of pathogenic organisms. Four chemical disinfectants and rinsing with municipal tap water were evaluated for their ability to disinfect nets used to capture zebrafish. The disinfectants included benzalkonium chloride+methylene blue, sodium hypochlorite, chlorine dioxide, and potassium peroxymonosu...

  2. Effect of alginate chemical disinfection on bacterial count over gypsum cast

    OpenAIRE

    Haralur, Satheesh B.; Al-Dowah, Omir S.; Gana, Naif S.; Al-Hytham, Abdullah

    2012-01-01

    PURPOSE To evaluate the efficacy of sodium hypochlorite (1 : 10) and iodophor disinfectants on alginate impressions along with their effect on the survived bacterium count on the gypsum cast. MATERIALS AND METHODS Four alginate impression on each dentate patients were made, of which Group I were not washed or disinfected, Group II impressions were merely washed with water, Group III were disinfected by spraying with sodium hypochlorite (1 : 10), Group IV were disinfected with iodophor (1 : 21...

  3. Conventional and Alternative Disinfection Methods of Legionella in Water Distribution Systems – Review

    Directory of Open Access Journals (Sweden)

    Pūle Daina

    2016-12-01

    Full Text Available Prevalence of Legionella in drinking water distribution systems is a widespread problem. Outbreaks of Legionella caused diseases occur despite various disinfectants are used in order to control Legionella. Conventional methods like thermal disinfection, silver/copper ionization, ultraviolet irradiation or chlorine-based disinfection have not been effective in the long term for control of biofilm bacteria. Therefore, research to develop more effective disinfection methods is still necessary.

  4. Zeolites modified with silver for the development of a water disinfection system

    International Nuclear Information System (INIS)

    Aparicio V, S.

    2013-01-01

    In spite of great strides that have been taken in sanitation technologies, there still exist health problems due to microbiological contamination by water. The waterborne diseases have not been completely eradicated and are a big problem of economic interest and health. Moreover, the microbicidal properties of silver have been used for a long time. The use of silver as a disinfectant has many advantages; for example it inhibits a wide spectrum of microorganisms, it has oligo dynamic properties and owing its mechanisms of cell inactivation, it also does not allow the emergence of new resistant strains. In the present research, the kinetics of water disinfection with silver has been investigated, to develop small system for water disinfection, based in silver modified Mexican clinoptilolite. The chemical species of silver play a significant role in the disinfection processes. For this reason, in this work, were both the Ag + and nanoparticles of Ag ο considered. The synthesis of nanoparticles of Ag ο woes performed by thermal and chemical reduction. It was found that the chemical reduction of Ag + to Ag ο was more efficient because it presented more defined nano structures and better distribution than those of thermal reduction. Clinoptilolite of Taxco (Guerrero) was chosen to exchange the native ions from the clinoptilolite by Ag + from the aqueous medium, or to deposit the nanoparticles of Ag ο on this surface. These silver modified zeolitic materials were characterized by scanning electron microscopy (Sem), elemental analyses (EDS), X-ray diffraction (XRD) and neutron activation analysis (NAA). The results showed that the crystallographic structure of the clinoptilolite did not change during thermal and chemical reduction treatments of Ag + to obtain the nanoparticles of Ag ο . The bactericide activity of the silver modified zeolitic materials (with Ag + or nanoparticles of Ag ο ) was evaluated on Escherichia coli Atcc 8739, in both distilled water and well

  5. 40 CFR 141.709 - Developing the disinfection profile and benchmark.

    Science.gov (United States)

    2010-07-01

    ... Cryptosporidium Disinfection Profiling and Benchmarking Requirements § 141.709 Developing the disinfection profile...) of the water before or at the first customer and prior to each additional point of disinfectant...) before or at the first customer during peak hourly flow. (ii) Determine successive CTcalc/CT99.9 values...

  6. 9 CFR 51.8 - Disinfection of premises, conveyances, and materials.

    Science.gov (United States)

    2010-01-01

    ... facilities, conveyances, or other materials on the premises that would require such cleaning and disinfection... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Disinfection of premises, conveyances... ANIMALS DESTROYED BECAUSE OF BRUCELLOSIS Indemnity for Cattle, Bison, and Swine § 51.8 Disinfection of...

  7. 9 CFR 91.18 - Cleaning and disinfection of transport carriers for export.

    Science.gov (United States)

    2010-01-01

    ... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Cleaning and disinfection of transport....18 Cleaning and disinfection of transport carriers for export. All fittings, utensils and equipment... port. Such disinfection of halters, ropes, and similar equipment used in handling and tying of animals...

  8. 9 CFR 77.19 - Cleaning and disinfection of premises, conveyances, and materials.

    Science.gov (United States)

    2010-01-01

    ... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Cleaning and disinfection of premises... PRODUCTS TUBERCULOSIS Cattle and Bison § 77.19 Cleaning and disinfection of premises, conveyances, and... health officials. Cleaning and disinfection must be completed before the premises, conveyances, or...

  9. 9 CFR 53.7 - Disinfection of premises, conveyances, and materials.

    Science.gov (United States)

    2010-01-01

    ... least 7 days following such cleaning and disinfection, unless the Administrator determines that a... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Disinfection of premises, conveyances... LIVESTOCK OR POULTRY § 53.7 Disinfection of premises, conveyances, and materials. All premises, including...

  10. 9 CFR 77.41 - Cleaning and disinfection of premises, conveyances, and materials.

    Science.gov (United States)

    2010-01-01

    ... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Cleaning and disinfection of premises... PRODUCTS TUBERCULOSIS Captive Cervids § 77.41 Cleaning and disinfection of premises, conveyances, and... health officials. Cleaning and disinfection must be completed before the premises, conveyances, or...

  11. Application of neutral electrolyzed water to disinfection of alginate impression.

    Science.gov (United States)

    Nagamatsu, Yuki; Chen, Ker-Kong; Nagamatsu, Hiroshi; Kozono, Yoshio; Shimizu, Hiroshi

    2016-01-01

    Neutral electrolyzed water was developed with new concepts of long-term good durability and minimum corrosiveness to metal in addition to its excellent bactericidal activities similar to acid type of electrolyzed waters. The present study examined the bactericidal effects of the neutral electrolyzed water on disinfection of the alginate impression of a dental arch model contaminated by bacteria. Only 1-min immersion in neutral electrolyzed water could sufficiently disinfect the alginate impression including the metallic tray under ultrasonic with no significant differences from acid electrolyzed waters. No bactericidal effects were found in any electrolyzed water when used as mixing water. Considering the advantages and disadvantages of each electrolyzed water in a comprehensive way, it was suggested that neutral electrolyzed water may be the most appropriate for the disinfection of alginate impression.

  12. Drinking water and biofilm disinfection by Fenton-like reaction.

    Science.gov (United States)

    Gosselin, F; Madeira, L M; Juhna, T; Block, J C

    2013-10-01

    A Fenton-like disinfection process was conducted with Fenton's reagent (H2O2) at pH 3 or 5 on autochthonous drinking water biofilms grown on corroded or non-corroded pipe material. The biofilm disinfection by Fenton-like oxidation was limited by the low content of iron and copper in the biomass grown on non-corroded plumbing. It was slightly improved by spiking the distribution system with some additional iron source (soluble iron II or ferrihydrite particles appeared as interesting candidates). However successful in situ disinfection of biofilms was only achieved in fully corroded cast iron pipes using H2O2 and adjusting the pH to 5. These new results provide additional support for the use of Fenton's processes for cleaning drinking water distribution systems contaminated with biological agents or organics. Copyright © 2013 Elsevier Ltd. All rights reserved.

  13. Disinfection of bacteria attached to granular activated carbon.

    Science.gov (United States)

    LeChevallier, M W; Hassenauer, T S; Camper, A K; McFeters, G A

    1984-01-01

    Heterotrophic plate count bacteria, coliform organisms, and pathogenic microorganisms attached to granular activated carbon particles were examined for their susceptibility to chlorine disinfection. When these bacteria were grown on carbon particles and then disinfected with 2.0 mg of chlorine per liter (1.4 to 1.6 mg of free chlorine residual per liter after 1 h) for 1 h, no significant decrease in viable counts was observed. Washed cells attached to the surface of granular activated carbon particles showed similar resistance to chlorine, but a progressive increase in sublethal injury was found. Observations made by scanning electron microscope indicated that granular activated carbon was colonized by bacteria which grow in cracks and crevices and are coated by an extracellular slime layer. These data suggest a possible mechanism by which treatment and disinfection barriers can be penetrated and pathogenic bacteria may enter drinking water supplies. Images PMID:6508306

  14. Solar water disinfecting system using compound parabolic concentrating collector

    Energy Technology Data Exchange (ETDEWEB)

    El-Ghetany, H.H.; Saitoh, T.S. [Tohoku Univ., Sendai (Japan)

    2000-05-31

    Solar water disinfection is an alternative technology using solar radiation and thermal treatment to inactivate and destroy pathogenic microorganisms present in water. The Compound Parabolic Concentrating, (CPC) collector can be used as an efficient key component for solar disinfectanting system. Two types of the CPC collectors are studied, namely the transparent-tube and the Copper-tube CPC collector. It is found that after 30 minutes of exposing the water sample to solar radiation or heating it up to 65 degree C for a few minuets all the coliform bacterial present in the contaminated water sample were completely eliminated. In this article, the effect of water temperature on the disinfecting process was presented. Thermal and micro-biological measurements were also made to evaluate the system performance. (author)

  15. Disinfection procedures for in vitro propagation of Anthurium

    Directory of Open Access Journals (Sweden)

    Silva Jaime A. Teixeira da

    2015-06-01

    Full Text Available Disinfection of plant material is the most important step of the tissue culture protocol. In this process, an attempt is made to eliminate microbial contaminants from the surface and interior of plant material, thus giving the explant a fighting chance at survival in vitro. Initial cultures of Anthurium species and cultivars, which are usually established from ex vitro material grown in a greenhouse, pots or in the field, easily contaminate the in vitro milieu. This review highlights the differences in disinfection protocols that exist for different species or cultivars of Anthurium. The protocol needs to be adjusted based on the material used: spadices, spathes, seeds, leaves, or roots. Regrettably, most of the currently published protocols, derived from a literature that spans over 100 published papers, have numerous weaknesses and flaws in the information provided pertaining to disinfection and infection levels. Advice for future Anthurium researchers should thus be followed cautiously.

  16. Biophysical methods for disinfection and stimulation of wheat seeds

    International Nuclear Information System (INIS)

    Marinkovic, S.; Marinkovic, B.

    2007-01-01

    In this paper we are shown results of applying electron treatment (disinfection of seed by electrons), and RIES method (electromagnetic seed stimulation). Four cultivars of wheat were used in this trial: Renesansa, Durumko, NS-Rana 5 and Sonata. Seed was treated with fast electrons and just before sowing stimulated by ultra low frequency electromagnetic field (from 0 to 100 Hz). For seed disinfection was used chemical treatment as well, as control variant. Control variant for all treatments was seed without any disinfection. The highest number of spikelets per spike was obtained at variant H+RIES. The highest spike length was obtained at variants e sup(-) + RIES and control. At variant H+RIES was achieved the highest grain number. Treatment H had influence on decreasing of grain mass per spike in relation to control variant, for significant value of 0.15 g. The highest grain mass per spike was obtained at variant e sup(-) + RIES

  17. A novel cupping-assisted plasma treatment for skin disinfection

    Science.gov (United States)

    Xiong, Zilan; Graves, David B.

    2017-02-01

    A novel plasma treatment method/plasma source called cupping-assisted plasma treatment/source for skin disinfection is introduced. The idea combines ancient Chinese ‘cupping’ technology with plasma sources to generate active plasma inside an isolated, pressure-controlled chamber attached to the skin. Advantages of lower pressure include reducing the threshold voltage for plasma ignition and improving the spatial uniformity of the plasma treatment. In addition, with reduced pressure inside the cup, skin pore permeability might be increased and it improves attachment of the plasma device to the skin. Moreover, at a given pressure, plasma-generated active species are restricted inside the cup, raising local reactive species concentration and enhancing the measured surface disinfection rate. A surface micro-discharge (SMD) device is used as an example of a working plasma source. We report discharge characteristics and disinfection efficiency as a function of pressure and applied voltage.

  18. [Disinfectants for the skin of premature].

    Science.gov (United States)

    Cucurachi, G; Tuoto, M G

    2010-06-01

    Nosocomial infections are among the leading causes of mortality and morbidity in neonatal intensive care units. Prevention of healthcare-associated infections is based on strategies that aim to limit susceptibility to infections by enhancing host defences, interrupting trasmission of organisms by healthcare workers and by promoting the judicious use of antimicrobials. Strategies for the prevention of nosocomial infections include hand hygiene practices, prevention of central venous (cvc)-related bloodstream infections, judicious use of antimicrobials for therapy, enhancement of host defences, skin care and early enteral feeding with human milk. Major concerns about the use of alcoholic chlorhexidine are for the high risk of skin burns in extremely premature infants during the first days of life, when the skin is thin and not fully keratinesed. Aqueous chlorhexidine could be less irritant when used in very low birthweigth infants and thus could represent a good option. A recent prospective trial of adult patients showed similar effectiveness of alcoholic and aqueos solutions of chlorexidine. However, to date no study evaluated whether the aqueos formulation is less harmful and as effective as the alcoholic formulation in neonatal infants. The lack of evidence for neonatal patients prompts urgent need for large randomised controlled trials comparing effectiveness and safety of different skin disinfectants before CVC placement in neonates and particulary in very low birth-weight infants. Nosocomial infections are still of the most serious problems for the neonatal intensive care unit. Therefore every effort must be implemented to reduce the incidence of these infections, can not be considered a toll required hospitalization, as it may not be acceptable for a place of shelter and care as the hospital may itself be a source of disease.

  19. Generation of ozone foam and its application for disinfection

    Science.gov (United States)

    Hiragaki, Keisuke; Ishimaru, Tomiya; Nakanishi, Masaru; Muraki, Ryouji; Nieda, Masanori; Yamabe, Chobei

    2015-07-01

    Generated ozone foam was applied to the disinfection of Pseudomonas fluorescens. The effect of disinfection has been confirmed experimentally and new equipment for the disinfection of hands using this ozone foam has been put on the market for the practical use. The ozone foam was produced in the foam generator after mixing the water including surfactant (30 mL/min) and air including ozone (1000 ppm = 2.14 g/m3 ~ 1600 ppm = 3.4 g/m3, 300 mL/min). The liquid-to-gas ratio is 100 L/m3. The concentration of dissolved ozone in the thin liquid films of the bubbles was about 3 mg/L which was measured by the chemical method of the KI absorption and titration of sodium thiosulfate solution. The disinfection test samples were prepared using the PET disk on which Pseudomonas fluorescens of its number of more than 108 were attached. Test sample was inserted into ozone foam set on the glass plate for one to 6 min. The survival rate log (N/N0 decreased with time and its value of about-2.6 (i.e., ~1/400) was obtained at 6 min (2 min × 3 times repeated). It was also confirmed that the ozone foam was useful for the disinfection of hands. For more effective disinfection (in case of taking a long time for foam melting), the ozone foam was broken by force and changed into ozone water by which the survival rate decreased ×4 (i.e., N/N0 = 1/10 000) at 4 ~ 6 min. Contribution to the topical issue "The 14th International Symposium on High Pressure Low Temperature Plasma Chemistry (HAKONE XIV)", edited by Nicolas Gherardi, Ronny Brandenburg and Lars Stollenwark

  20. Effect of new disinfectant substances on pseudomonas aeruginosa

    International Nuclear Information System (INIS)

    Majtan, V.

    1998-01-01

    The anti-bacterial effect of 13 new commercially manufactured disinfectant substances on P. aeruginosa strain was studied. The substances tested represent 9 quaternary ammonium salts QAT and 4 combined QAT with other ingredients. The antimicrobial efficacy was characterised by influencing the growth and reproduction of bacterial cells expressed either by MIC and ED 50 as well as and ED 50 , as well as by the inhibition of incorporation rate of incorporation rate of [ 14 C] adenine and [ 14 C] leucine. The method of inhibition of [ 14 C] precursors is suitable as one from possible evaluation criterion on anti-bacterial efficacy of synthetic disinfectant substances. (authors)

  1. [Control of disinfection in the buildings of pig farms].

    Science.gov (United States)

    Maris, P

    1990-01-01

    A survey carried out in pig farms was undertaken in order to compare 4 disinfectants used in 13 disinfecting operations, during the vacation period. It was immediately noticeable that after swabbing and counting the staphylococci, the chloramine T-based preparation was more effective than the quaternary ammonium-aldehyde association, phenolic acid derivatives or the quaternary ammonium preparations. We then observed that although the number of organisms decreased by 99.8%, their number on slatted floors still ranged between 0.02 x 10(4) and 3 x 10(4) per cm2.

  2. Monitoring and improving the effectiveness of surface cleaning and disinfection.

    Science.gov (United States)

    Rutala, William A; Weber, David J

    2016-05-02

    Disinfection of noncritical environmental surfaces and equipment is an essential component of an infection prevention program. Noncritical environmental surfaces and noncritical medical equipment surfaces may become contaminated with infectious agents and may contribute to cross-transmission by acquisition of transient hand carriage by health care personnel. Disinfection should render surfaces and equipment free of pathogens in sufficient numbers to prevent human disease (ie, hygienically clean). Copyright © 2016 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

  3. Visible light photocatalytic disinfection of E. coli with TiO2-graphene nanocomposite sensitized with tetrakis(4-carboxyphenyl)porphyrin

    Science.gov (United States)

    Rahimi, Rahmatollah; Zargari, Solmaz; Yousefi, Azam; Yaghoubi Berijani, Marzieh; Ghaffarinejad, Ali; Morsali, Ali

    2015-11-01

    The present research deals with the development of a new heterogeneous photocatalysis system for disinfection of bacteria from wastewater by using TiO2-graphene (TG) nanocomposite sensitized with tetrakis(4-carboxyphenyl)porphyrin (TCPP). The disinfection of wastewater using this photocatalyst is not reported in the literature yet. All the synthesized materials were thoroughly characterized by Raman, XRD, DRS, BET, and SEM analysis. The optimum content of graphene in the TiO2-graphene nanocomposite was determined by photocurrent responses of prepared photocatalysts. Subsequently, the photocurrent measurements demonstrate that the TiO2-graphene nanocomposite with 3% graphene content has higher photoactivity. Furthermore, sensitization of the TiO2-graphene nanocomposite with porphyrin (TGP) is successfully capable to develop a new type of photocatalyst system for disinfection of bacteria with moderate to high yields in visible light irradiation.

  4. [Experiments on disinfection of vaccinia virus embedded in scabs and/or at the hand].

    Science.gov (United States)

    Schümann, K; Grossgebauer, K

    1977-01-01

    Vaccinia viruses embedded in rabbit dermal scabs were subjected to physical and chemical disinfection procedures. Scabs were suspended in vitro without saline or in physiological saline, and left for 1 hour at 70 to 90 degrees C. A complete inactivation was achived only in those scab samples which had been incubated at 90 degrees C for 1 hour and suspended in physiological saline. Scabs which had been placed in a disinfecting apparatus (Vacudes 4000) filled with mattrasses consistently proved to be free of infectious vaccinia viruses in each of the chosen programs. In addition scabs were subjected to disinfection by means of chemical disinfecting agents. The scabs had been placed in a chemical disinfecting suspension and left there for 90 minutes. Complete disinfection was obtained with glutaraldehyde 2%, formaldehyde 2%, Lysoformin 2% or 3%, phenol 5% and chloramine T 2%. Complete disinfection was likewise achieved after 3 hours treatment with some alchohols (ethylalcohol 80%, isopropylalcohol 7%, n-propylalcohol 60%), Amocid 5% and formaldehyde 1%.0.5% formaldehyde caused complete disinfection when applied for 6 hours. The only exception was a Quat which did not disinfect fully even after 18 hours application. Concerning the tests to disinfect the hands complete disinfection occurs when using chloramine T (1.5%) or isopropylalcohol (70%) in 2 to 5 minutes. Further tests were performed with scabs which were placed in sick rooms that were terminally disinfected with formaline vapor. It could be confirmed that the usual terminal disinfection with formaldehyde vapor was unable to completely disinfect the scabs. It is necessary to double the amount of formaldehyde (10 g formaldehyde per cubic metre of space) and prolong the period of treatment to 24 hours to achieve a greater degree of disinfection rate.

  5. Control of dangerous substances in discharges and microbiological abatement: European framework and a case study of an ozone disinfection system.

    Science.gov (United States)

    Ostoich, M; Serena, F; Falletti, L; Fantoni, A

    2013-01-01

    Directive 2000/60/EC requires the achievement of a 'good chemical status' for surface water within pre-established dates. Disinfection is needed to achieve compulsory final microbial limit values (in Italy for wastewater discharges the parameter Escherichia coli - EC - is imposed by law with a maximum limit value of 5,000 cfu/100 mL). Liquid waste and disinfection by-products must be considered when designing appropriate monitoring of dangerous substances; the specific classes of substances must be investigated according to the typology of received wastewaters and liquid wastes (where applicable) and specific analytical techniques, with Limit of Detection (LOD) lower than the limit values, must be applied; the difficulties faced by national and regional environmental control Agencies is that these techniques have to be applied during ordinary activity and not only for research purposes. The study aims to present the control of dangerous substances, as a screening view, in wastewater treatment plant (WWTP) discharges in the province of Venice (Northern Italy) for the period 2007-2010 based on available data from institutional controls. In addition, the wastewater disinfection process with ozone applied to a medium size WWTP (45,000 Population Equivalents) is presented as a case study, with a view to assessing the microbiological abatement efficacy and the presence of dangerous substances. Discharge quality of the WWTPs in the province of Venice presented mean values that were higher than the LOD, but only for certain metals. For the Paese plant, zinc and chloroform were the only micro-pollutants detected with a higher level than the LOD. From microbiological data in the period 2006-2011 the disinfection abatement efficiency for Paese was, in most cases above 99% for EC, faecal coliform (FC), faecal streptococci (FS) while efficiency was slightly lower for total coliform (TC); however, the proposed criterion aimed at respecting 99.99% abatement was not completely

  6. Application of a high-level peracetic acid disinfection protocol to re-process antibiotic disinfected skin allografts.

    Science.gov (United States)

    Lomas, R J; Huang, Q; Pegg, D E; Kearney, J N

    2004-01-01

    Skin allografts, derived from cadaveric donors, are widely used for the treatment of burns and ulcers. Prior to use in clinical situations, these allografts are disinfected using a cocktail of antibiotics and then cryopreserved. Unfortunately, this antibiotic disinfection procedure fails to decontaminate a significant proportion and these contaminated grafts can not be used clinically. We have investigated whether it is possible to apply a second, more potent disinfection procedure to these contaminated grafts and effectively to re-process them for clinical use. Cadaveric skin grafts, treated with antibiotics and cryopreserved, were thawed and a peracetic acid (PAA) disinfection protocol applied. The grafts were then preserved in a high concentration of glycerol or propylene glycol, and properties thought to be essential for successful clinical performance assessed. The cytotoxicity of the grafts was assessed using both extract and contact assays; damage to the skin collagen was assessed using a collagenase susceptibility assay and the capacity of the grafts to elicit an inflammatory response in vitro was assessed by quantifying the production of the pro-inflammatory cytokine TNF-alpha by human peripheral blood mononuclear phagocytes. PAA disinfection, in conjunction with either glycerol or propylene glycol preservation, did not render the grafts cytotoxic, pro-inflammatory, or increase their susceptibility to collagenase digestion. The rates of penetration of glycerol and propylene glycol into the re-processed skin were comparable to those of fresh skin. This study has demonstrated that PAA disinfection combined with immersion in high concentrations of either glycerol or propylene glycol was an effective method for re-processing contaminated skin allografts, and may justify their clinical use.

  7. Analysis of microstructural evolution driven by production bias

    International Nuclear Information System (INIS)

    Woo, C.H.; Semenov, A.A.; Singh, B.N.

    1993-01-01

    The concept of production bias was first considered in the preceding workshop in this series at Silkeborg in 1989. Since then, much work has been done to investigate the validity of the concept, and its usefulness in complementing the current theory of microstructure evolution based solely on the sink bias (e.g., dislocation bias) as a driving force. Comparison of the theory with experimental results clearly supports the concept. The present paper reviews and summarizes these investigations, and arrives at the following conclusions: a) the concept of production bias is consistent with the results of other works which indicates that, under cascade damage conditions, the effective rate of point-defect production is only a small fraction of the NRT displacement production rate; b) the defect accumulation under cascade damage conditions can be understood in terms of production bias; and c) although the existence of conventional dislocation bias due to point-defect dislocation interaction is not questioned, it does not seem to play any major role in the accumulation of defects under cascade damage conditions at elevated temperatures. (orig.)

  8. Disinfection ultraviolet radiation bulk food products

    OpenAIRE

    Семенов, А. А.

    2014-01-01

    В работе представлены результаты обеззараживания сыпучих пищевых продуктов ультрафиолетовым излучением. Предложена технология бактерицидного обеззараживания сыпучих продуктов с размером частиц до 50 мкм. Проведены необходимые расчеты, связанные с дозой облучения, с временем пребывания частиц в зоне облучения и необходимой дозой инактивации в зависимости от вида бактерий. Considered the results of bulk food products disinfection by ultraviolet radiation. The technology bactericidal disinfec...

  9. Disinfection efficiency of chlorine dioxide gas in student cafeterias in Taiwan.

    Science.gov (United States)

    Hsu, Ching-Shan; Huang, Da-Ji

    2013-07-01

    In Taiwan, the food and drink requirements of students and faculty members are met by student cafeterias. The air quality within these cafeterias should satisfy the guidelines laid down by the Taiwan Environmental Protection Agency (Taiwan EPA). Accordingly, this study performed an experimental investigation into the efficiency of two different gaseous chlorine dioxide (ClO2) treatments in disinfecting a local student cafeteria, namely a single, one-off application and a twice-daily application. In both cases, the ClO2 was applied using strategically placed aerosol devices. The air quality before and after disinfection was evaluated by measuring the bioaerosol levels of bacteria and fungi. Moreover, a stepwise discriminant analysis method was applied for predicting the residual concentrations of bacteria and fungi, as a function of the environmental parameters and the ClO2 concentration. The experimental results showed that the average background levels of bacteria and fungi prior to ClO2 disinfection were 972.5 +/- 623.6 and 1534.1 +/- 631.8 colony-forming units (CFU)/m3, respectively. A single ClO2 application was found to reduce the bacterial and fungal concentration levels by as much as 65% and 30%, respectively. By contrast, a twice-daily ClO2 application was found to reduce the bacterial and fungal concentration levels by as much as 74% and 38%, respectively. The statistical analysis results showed that the residual bacterial concentration level was determined primarily by the number of individuals present in the cafeteria, the temperature, and the ClO2 concentration, whereas the residual fungal concentration level was determined mainly by the temperature, the total number of suspended particles, and the ClO2 concentration. Thus, the integrated results suggest that the air quality guidelines prescribed by the Taiwan EPA for student cafeteria can best be achieved by applying ClO2 twice daily using an appropriate deployment of aerosol devices. ClO2 gas can

  10. Cobalt catalyzed peroxymonosulfate oxidation of tetrabromobisphenol A: Kinetics, reaction pathways, and formation of brominated by-products

    Energy Technology Data Exchange (ETDEWEB)

    Ji, Yuefei [Department of Environmental Science and Engineering, Nanjing Agricultural University, Nanjing 210095 (China); Kong, Deyang [Nanjing Institute of Environmental Science, Ministry of Environmental Protection of PRC, Nanjing 210042 (China); Lu, Junhe, E-mail: jhlu@njau.edu.cn [Department of Environmental Science and Engineering, Nanjing Agricultural University, Nanjing 210095 (China); Jin, Hao; Kang, Fuxing; Yin, Xiaoming; Zhou, Quansuo [Department of Environmental Science and Engineering, Nanjing Agricultural University, Nanjing 210095 (China)

    2016-08-05

    Highlights: • Cobalt catalyzed peroxymonosulfate oxidation of tetrabromobisphenol A. • Phenolic moiety was the reactive site for sulfate radical attack. • Pathways include β-scission, oxidation, debromination and coupling reactions. • Brominated disinfection by-products were found during TBBPA degradation. • Humic acid inhibited TBBPA degradation but promoted DBPs formation. - Abstract: Degradation of tetrabromobisphenol A (TBBPA), a flame retardant widely spread in the environment, in Co(II) catalyzed peroxymonosulfate (PMS) oxidation process was systematically explored. The second-order-rate constant for reaction of sulfate radical (SO{sub 4}{sup ·−}) with TBBPA was determined to be 5.27 × 10{sup 10} M{sup −1} s{sup −1}. Apparently, degradation of TBBPA showed first-order kinetics to the concentrations of both Co(II) and PMS. The presence of humic acid (HA) and bicarbonate inhibited TBBPA degradation, most likely due to their competition for SO{sub 4}{sup ·−}. Degradation of TBBPA was initiated by an electron abstraction from one of the phenolic rings. Detailed transformation pathways were proposed, including β-scission of isopropyl bridge, phenolic ring oxidation, debromination and coupling reactions. Further oxidative degradation of intermediates in Co(II)/PMS process yielded brominated disinfection by-products (Br-DBPs) such as bromoform and brominated acetic acids. Evolution profile of Br-DBPs showed an initially increasing and then decreasing pattern with maximum concentrations occurring around 6–10 h. The presence of HA enhanced the formation of Br-DBPs significantly. These findings reveal potentially important, but previously unrecognized, formation of Br-DBPs during sulfate radical-based oxidation of bromide-containing organic compounds that may pose toxicological risks to human health.

  11. Disinfection/sterilization of extracted teeth for dental student use.

    Science.gov (United States)

    Dominici, J T; Eleazer, P D; Clark, S J; Staat, R H; Scheetz, J P

    2001-11-01

    Extracted human teeth are used in many preclinical courses. While there has been no report of disease transmission with extracted teeth, sterilization of teeth used in the teaching laboratory should be a concern. The purpose of this study was to determine the effectiveness of different sterilization/disinfection methods of extracted human teeth using Bacillus stearothermophilus, a bacteria resistant to heat and frequently used to test sterilizers. In this study, 110 extracted molars with no carious lesions were collected and stored in buffered saline. An endodontic occlusal access preparation was cut into the pulp chamber of each tooth. Pulp tissue in the chamber was removed with a broach. Approximately 1 x 10(5) B. stearothermophilus endospores in culture medium were injected into the pulp chamber, sealed with Cavit G, and then placed in sterile saline for twelve hours. Ten teeth were placed into each of eleven groups. Seven groups were immersed for one week in one of the following solutions: a) sterile saline (control group), b) 5.25% NaOCl, c) 2.6% NaOCl, d) 1% NaOCl, e) 10% buffered formalin, f) 2% gluteraldehyde, g) 0.28% quaternary ammonium. Four additional groups were treated by h) 10% formalin for two days, i) 10% formalin for four days, j) autoclaving at 240 degrees F and 20 psi for twenty minutes, and k) autoclaving at 240 degrees F and twenty psi for forty minutes. Each tooth was then aseptically split and placed in an individual test tube with growth medium. Samples were examined for evidence of growth (turbidity) at forty-eight hours. Only autoclaving for forty minutes at 240 degrees F and 20 psi or soaking in 10 percent formalin for one week were 100 percent effective in preventing growth. A chi-square analysis of the data indicates these two methods were significantly better than all other methods (p<0.001).

  12. One plunge or two?--hand disinfection with alcohol gel.

    Science.gov (United States)

    Macdonald, Duncan J M; Mckillop, Elisabeth C A; Trotter, Sylvia; Gray, Alastair J R

    2006-04-01

    To compare health care workers' hand surface coverage using two different volumes of alcohol gel for hand disinfection. and methods. A total of 84 members of staff in our hospital were studied. Subjects were asked to disinfect their hands with alcohol gel containing a clear fluorescent substance. Performance was assessed by using UV light to identify areas which had been missed, and the total surface area missed was calculated. A total of 42 subjects received 3.5 ml of alcohol gel, and 42 age-, sex-, and job-matched subjects received 1.75 ml of alcohol gel. Significantly less area was missed when hand disinfecting with double the volume of alcohol gel; 1.23 versus 6.35% surface area was missed (P disinfection significantly improves the efficiency of coverage of the hands with alcohol gel. This may result in lower bacterial count on the hands and may reduce the spread of nosocomial infections including that of methicillin-resistant Staphylococcus aureus.

  13. Surface dielectric barrier discharge jet for skin disinfection

    NARCIS (Netherlands)

    Creyghton, Y.; Meijer, R.; Verweij, P.; Zanden, F. van der; Leenders, P.

    2012-01-01

    A consortium consisting of the research institute TNO, the medical -university and hospital St Radboud and two industrial enterprises is working on a non-thermal plasma treatment method for hand disinfection. The group is seeking for cooperation, in particular in the field of validation methods and

  14. Control of house-dust mites with home disinfectants

    NARCIS (Netherlands)

    Schober, G.; Wetter, G.; Bischoff, E.; Bronswijk, van J.E.M.H.; Kniest, F.M.

    1987-01-01

    Chemical disinfectants and biocidal preparations used in households were tested in the laboratory for their ability to kill the house-dust miteDermatophagoides farinae. Batches of ten specimens were soaked in aqueous solutions or suspensions containing 0.0, 0.1, 0.3, 1.0, 3.0 and 10.0% (by volume)

  15. 9 CFR 53.6 - Disinfection of animals.

    Science.gov (United States)

    2010-01-01

    ... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Disinfection of animals. 53.6 Section 53.6 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF... of animals. Animals of species not susceptible to the disease for which a quarantine has been...

  16. A parametrical study of disinfection with hydrodynamic cavitation.

    Science.gov (United States)

    Arrojo, S; Benito, Y; Tarifa, A Martínez

    2008-07-01

    The physical and chemical conditions generated by cavitation bubbles can be used to destroy microorganisms and disinfect wastewater. The effect of different cavitation chamber designs and diverse operational parameters on the inactivation rate of Escherichia coli have been studied and used to understand the mechanisms involved in cell disruption.

  17. Disinfection Alternatives for Small Communities in Puerto Rico

    Science.gov (United States)

    Disinfection Alternatives for Small Communities in Puerto Rico Craig Patterson1, Graciela Ramirez Toro2, Harvey Minnigh2, Cristina Maldonado3, and Rajib Sinha4 1U.S. EPA Office of Research and Development, 2Centro de Educación, Conservación e Interpretación Ambiental (CECIA),...

  18. A biocoagulant slow sand filtration for disinfection of Toxoplasma ...

    African Journals Online (AJOL)

    An integrated low-tech biocoagulant-sand filter drum for disinfection of oocysts of Toxoplasma gondii targeted for developing countries was evaluated. Dirty and turbid water (130.3 NTU) from Mezam River and leachates from dump sites and stagnant water in Bamenda, Cameroon, was analyzed microscopically after ...

  19. Assessment of peracetic acid disinfected effluents by microbiotests.

    Science.gov (United States)

    Antonelli, M; Mezzanotte, V; Panouillères, M

    2009-09-01

    Bioassays were performed by commercially available kits on peracetic acid (PAA) solutions, at different concentrations, and on secondary effluents (from two different wastewater treatment plants) after disinfection at bench-scale, considering both samples containing residual active PAA and the same samples where residual PAA was quenched. Four indicator organisms were used: Vibrio fischeri, Thamnocephalus platyurus, Daphnia magna, and Selenastrum capricornutum. The experiments lead to conclude that Thamnocephalus platyurus is a very sensitive organism, probably not adequate to perform a reliable toxicity assessment of effluents for monitoring purposes. The presence of specific organic compounds deriving from human metabolism and urban pollution, even at very low concentrations, can affect the results of bioassays, especially those performed on Vibrio fischeri. PAA is toxic for bacteria and crustaceans even at concentrations lower than the ones commonly used in wastewater disinfection (2-5 mg/L), while its effect on algae is smaller. The toxic effect on bacteria was expected, as PAA is used for disinfection, but its possible influence on biological processes in the receiving aquatic environment should be considered. Toxicity on crustaceans would confirm the fact that discharging disinfected effluents could raise some environmental problems.

  20. Wastewater disinfection alternatives: chlorine, ozone, peracetic acid, and UV light.

    Science.gov (United States)

    Mezzanotte, V; Antonelli, M; Citterio, S; Nurizzo, C

    2007-11-01

    Disinfection tests were carried out at pilot scale to compare the disinfection efficiency of ozone, sodium hypochlorite (NaOCl), peracetic acid (PAA), and UV irradiation. Total coliforms, fecal coliforms, and Escherichia coli were monitored as reference microorganisms. Total heterotrophic bacteria (THB) were also enumerated by cytometry. At similar doses, NaOCl was more effective than PAA, and its action was less affected by contact time. The results obtained by ozonation were comparable for total coliforms, fecal coliforms, and E. coli. On the contrary, some differences among the three indicators were observed for NaOCl, PAA, and UV. Differences increased with increasing values of the disinfectant concentration times contact time (C x t) and were probably the result of different initial counts, as total coliforms include fecal coliforms, which include E. coli. The UV irradiation lead to complete E. coli removals, even at low doses (10 to 20 mJ/cm2). Total heterotrophic bacteria appeared to be too wide a group to be a good disinfection indicator; no correlation was found among THB inactivation, dose, and contact time.

  1. 7 CFR 301.89-12 - Cleaning, disinfection, and disposal.

    Science.gov (United States)

    2010-01-01

    ... indica must be cleaned and disinfected in accordance with § 301.89-13 prior to being used in the conditioning of seed that has tested negative for the spores of Tilletia indica or to being moved from a... move bunted-kernel-positive host crops, including trucks, railroad cars, and other containers, that...

  2. A prototype catheter designed for ultraviolet C disinfection

    DEFF Research Database (Denmark)

    Bak, Jimmy; Begovic, Tanja

    2013-01-01

    UVC light exposure, sampling and plate counting. Findings Two minutes of UVC exposure was sufficient to obtain 4 log10 disinfection for the full-length prototype catheter. This exposure corresponds to ∼40 mJ/cm2 at the catheter tip and indicates that even shorter exposure times can be achieved...

  3. The Effect of Various Brands of Chloroxylenol disinfectants on Some ...

    African Journals Online (AJOL)

    Suspension and surface viability tests were carried out to determine the effects of various brands of chloroxylenol disinfectants on clinically important nosocomial gram negative and gram-positive organisms. Dettol and morigard brands of chloroxylenol inhibited gram-positive organisms at a dilution of 1 in 50. Tiscol brand of ...

  4. UASB reactor effluent disinfection by ozone and chlorine

    NARCIS (Netherlands)

    Ribeiro da Silvia, G.H.; Bruning, H.; Gerrity, D.; Daniel, L.A.

    2015-01-01

    This research studied the sequential ozone and chlorine process with respect to, the inactivation of indicator bacteria and the formation of ozone disinfection byproducts in sanitary wastewater effluent. The applied ozone doses were 5, 8 and 10 mg.O3.L-1, followed by chlorine doses of 10, 20 and 30

  5. A practical evaluation of detergent and disinfectant solutions on ...

    African Journals Online (AJOL)

    Student01

    2012-01-06

    Jan 6, 2012 ... inactivation efficacy and effect on material corrosion ... Cleaning and disinfection agents were evaluated against selected bacteria on ... bacteria strains: Escherichia coli K12, E. coli DSM 682, Salmonella ... in terms of the lifespan of the equipment, and also ..... Individual descriptions of the observed basis.

  6. [The effect of disinfectant soaking on dental gypsum model size].

    Science.gov (United States)

    Zhu, Cao-yun; Xu, Yun-wen; Xu, Kan

    2012-12-01

    To study the influence of disinfectant soaking on the dimensional stability of three kinds of dental gypsum model. Three commonly used gypsums ( type III,IV,Vtype) in clinic were used to make 24 specimens for 50 mm×15 mm×10 mm in size. One hour after release, the specimens were placed for 24 h. A digital caliper was used to measure the size of the gypsum model. Distilled water immersion was as used control, glutaraldehyde disinfectant and Metrix CaviCide disinfectant soaking were used for the experimental group. After soaking for 0.5h, the gypsum models were removed and placed for 0.5 h, 1 h, 2 h, 24 h. The size of the models was measured again using the same method. The data was analyzed with SPSS10.0 software package. The initial gypsum model length was (50.07±0.017) mm, (50.048±0.015) mm and (50.027±0.015) mm. After soaking for different times, the size of the model changed little, and the dimensions changed less than 0.01%. The results show that disinfectant soaking has no significant effect on dental model dimensions.

  7. Effects of Ozone and Photo‑Activated Disinfection against ...

    African Journals Online (AJOL)

    Objectives: The purpose of this study was to compare the antibacterial effects of gaseous ozone (O3) and photo‑activated disinfection (PAD) methods against Enterococcus faecalis (E. faecalis) biofilms. Materials and Methods: Sixty‑five human mandibular premolars with straight root canals were selected. After root canal ...

  8. Moist Heat Disinfection and Revisiting the A0 Concept.

    Science.gov (United States)

    McCormick, Patrick J; Schoene, Michael J; Dehmler, Matthew A; McDonnell, Gerald

    2016-04-02

    Moist heat is employed in the medical device, pharmaceutical, and food processing industries to render products and goods safe for use and human consumption. Applications include its use to pasteurize a broad range of foods and beverages, the control of microbial contamination of blood products, and treatment of bone tissue transplants and vaccines. In the pharmaceutical industry, water heated to 65°C to 80°C is used to sanitize high-purity water systems. In healthcare, it has been employed for decades to disinfect patient care items ranging from bedpans to anesthesia equipment. There is a good understanding of the conditions necessary to achieve disinfection of microorganisms at temperatures ranging from 65°C to 100°C. Based on this information, the efficacy of moist heat processes at a range of exposure times and temperatures can be quantified based on mathematical models such as the A0 calculation. While the A0 concept is recognized within the European healthcare community, it has yet to be widely adopted within the United States. This article provides information regarding the A0 concept, a brief overview of the classification of thermal disinfection for use with healthcare applications within the United States, and recent data on reinvestigating the thermal disinfection of a selected panel of microorganisms and a mixed culture biofilm.

  9. Technical and economical feasibility study of a sewage sludge disinfection plants by irradiation process

    International Nuclear Information System (INIS)

    Rojas Bustos, Gustavo

    1999-01-01

    This report presents a technical and economical evaluation for a disinfection plant of sewage sludge based on irradiation. The process starts after sludge stabilization which is achieved by anaerobic digestion. It includes two stages, plus an optional: the first corresponds to dewatering of sewage sludge up to a solids content between 20 and 25 %, the second stage corresponds to disinfection by gamma or electron beam irradiation, and the third, which is optional, corresponds to the drying of sewage sludge up to a water content of 50%, which allows to diminish significantly the volumes of solids to be transported. If this stage is not accomplished the final product corresponds to a sewage sludge with 25 % of dry solids, which can also be disposed in agricultural land. Process was designed to treat 60 tons per day of sewage sludge (dry matter basis). The report presents the design of process equipment, principal and auxiliary, the investment and operational cost estimations as well as the total cost of treatment per ton of sewage sludge. A sensitivity analysis is also included to determine the influence of operational process parameters in operational and investment costs. The results showed that a sewage sludge plant including dewatering and disinfection process through gamma irradiation, achieves a capital investment of about US$ 12.000.000 with a treatment cost per ton of dry sludge of US$140. Including the optional air-drying stage, the total cost of treatment is about US$148 per ton of dry matter. In the case of electron beam irradiation the capital investment achieves a value of US$ 11 millions with a total treatment cost of US$ 136 per ton of dry matter. These values resulted quite similar to the cost of alternative treatment, i.e., disposal in a dedicated landfill. (L.V.)

  10. Clinical effect of calcium hydroxide paste combined with triple antibiotic paste on root canal disinfection

    Directory of Open Access Journals (Sweden)

    Chen QU

    2014-03-01

    Full Text Available Objective To compare the efficacy in disinfection and pain control of calcium hydroxide paste and triple antibiotic paste (ornidazole, ciprofloxacin and minocycline used individually or jointly for root canal disinfection. Methods Two hundred and thirty-five patients with chronic apical periodontitis (235 teeth were involved in the present study and divided into 2 groups: fistula group (n=118 and no fistula group (n=117. Each group was then randomly divided into 4 subgroups: calcium hydroxide paste group, triple antibiotic paste group, calcium hydroxide + triple antibiotic paste group, and camphor phenol group. After regular root canal preparation, root canals of patients in 4 groups were filled with tiny paper ends impregnated with fore 4 different drugs respectively. Visual analogue scales (VAS of pain were given to the patients with a guide for filling the scale. One week later, both the data of the scales and the effects of root canal disinfection were recorded and analyzed. Results Seven days after treatment, the clinical efficacy of calcium hydroxide paste, triple antibiotic paste and calcium hydroxide + triple antibiotic paste was similar (P>0.05 either in fistula group or in no fistula group, but all better than that of camphor phenol (P<0.05. VAS score analysis showed that, at least on the first 3 days after sealing medicine in the root canal, calcium hydroxide + triple antibiotic paste achieved better result of pain control than the other three groups (P<0.05 no matter with or without fistula. Conclusions  Calcium hydroxide paste, triple antibiotic paste, calcium hydroxide + triple antibiotic paste are effective in treatment of chronic apical periodontitis whether with or without fistula. However, the combined use of calcium hydroxide and three antibiotic pastes is better for controlling the pain after root canal preparation than other treatments, which is therefore worthy of clinical application. DOI: 10.11855/j.issn.0577-7402.2014.02.12

  11. Clean coal technology. Coal utilisation by-products

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-08-15

    The need to remove the bulk of ash contained in flue gas from coal-fired power plants coupled with increasingly strict environmental regulations in the USA result in increased generation of solid materials referred to as coal utilisation by-products, or CUBs. More than 40% of CUBs were sold or reused in the USA in 2004 compared to less than 25% in 1996. A goal of 50% utilization has been established for 2010. The American Coal Ash Association (ACCA) together with the US Department of Energy's Power Plant Improvement Initiative (PPPI) and Clean Coal Power Initiative (CCPI) sponsor a number of projects that promote CUB utilization. Several are mentioned in this report. Report sections are: Executive summary; Introduction; Where do CUBs come from?; Market analysis; DOE-sponsored CUB demonstrations; Examples of best-practice utilization of CUB materials; Factors limiting the use of CUBs; and Conclusions. 14 refs., 1 fig., 5 tabs., 14 photos.

  12. [The principle of registration, evaluation and testing of disinfecting preparations].

    Science.gov (United States)

    Röhm-Rodowald, Ewa; Jakimiak, Bozenna; Podgórska, Marta

    2008-01-01

    Disinfectants are used to produce a state in which the number of living micro-organisms has been reduced to a level which is appropriate to the practical situation. For any products which are included in the Biocidal Directive 98/8/EC, for which specific activity is claimed, test data has to be approved by the regulatory authority and a product license obtained before the product can be offered for sale. Disinfectants can be recorded as biocidal products or medical devices. Presently, it is possible to measure the activity of a product on defined micro-organisms in specified experimental conditions. Efficacy is the result of the use of a product according to a defined application. To allow different requirements in different areas of application, separate tests and pass criteria have been or will be prepared for each of following three areas of application: medical, veterinary and group comprising food, industrial, domestic and institutional areas. The laboratory methods to be used for testing the activity of chemical disinfectants meets the European standards. The tests are categorised on a modular basis as follows: phase 1 tests, phase 2 step 1 tests, phase 2 step 2 tests and phase 3 tests. In order to claim that a product has disinfectant properties, suitable for use in the medical area, the product shall be tested according to European standards: phase 2 step 1 tests, phase 2 step 2 tests. Phase 1 tests are not required to support claims for chemical disinfectants used in human medicine. Only phase 1 tests are required to support claims for active substances for which no particular area of application is specified. Medical devices are subjects to the European Directive 93/42/EEC which requires that a product must carry a CE mark. Disinfectants which are intended specifically by its manufacturer to be used on medical devices are themselves medical devices and so these products, as well as conforming to the instrument disinfection European standards as specified

  13. Characterization of by-products from the Coolside process

    International Nuclear Information System (INIS)

    Wong, A.S.; Thomas, G.A.; Schram, W.H.; Givens, E.N.; Robertson, J.D.

    1993-01-01

    Coolside is a flexible dry flue gas desulfurization process for removal of SO 2 from coal fired power plants emissions. Hydrated lime is pneumatically injected dry into the power plant duct work on the cool side of the air preheater. The flue gas stream is then humidified to within about 20--30 F of adiabatic saturation by spraying atomized water. A critical component of the Coolside process is the addition of a promoter to the water spray to enhance SO 2 capture efficiency. In general, sodium based compounds have been found to be the most effective promoters, although chloride salts have also been shown to be effective if added during lime hydration. The Coolside technology was successfully demonstrated at the Ohio Edison Edgewater Plant as part of a US DOE supported US EPA demonstration program. The test lasted from July 1989 through February 1990 and had two primary goals. First, to achieve overall SO 2 reductions of 30%, 50%, and 70%. Second, to achieve reliable process operations at 20 and 25 F approach to adiabatic saturation. The demonstration was considered successful. The Coolside solids differ from other dry scrubber wastes in that the residual lime is hydrated and from other low temperature scrubbing wastes in that the sorbent activator, NaOH in this case, introduces significant quantities of sodium compounds in the waste. Sixty-five tons of the waste were collected during the demonstration runs in February 1990 in order to assess the environmental impact of the by-product through a series of field lysimeter and laboratory column leaching studies. In the first phase of this assessment, approximately 400 samples of the by-product material have been analyzed for the major, minor, and trace elements by the ultimate and proximate analysis, X-ray fluorescence, and PIXE/PIGE analysis. The results of these analyses and the unique chemistry of the Coolside solids as a function of processing variables is presented in this paper

  14. Transformation mechanism of benzophenone-4 in free chlorine promoted chlorination disinfection.

    Science.gov (United States)

    Xiao, Ming; Wei, Dongbin; Yin, Junxia; Wei, Guohua; Du, Yuguo

    2013-10-15

    The UV-filter BP-4 (2-hydroxy-4-methoxybenzophenone-5-sulfonic acid) has been frequently observed in the environment, showing high potentials to invade drinking water, swimming water, or wastewater reclamation treatment systems. With the help of high performance liquid chromatography-high resolution mass spectrometry and nuclear magnetic resonance spectroscopy, 10 new products from free chlorine-promoted BP-4 disinfection have been disclosed and their possible transformation routes have been investigated. The first route is chlorine substitution of BP-4 and its transformation products, forming mono-, di-, and tri-chlorinated BP-4 analogs. The second is Baeyer-Villiger-Type oxidation, converting diphenyl ketone to phenyl ester derivatives. The third is ester hydrolysis, generating corresponding phenolic and benzoic products. The fourth is decarboxylation, replacing the carboxyl group by chloride in the benzoic-type intermediate. The fifth is desulfonation, degrading the sulfonic group through an alternative chlorine substitution on the benzene ring. Orthogonal experiments have been established to investigate the species transformed from BP-4 at different pH values and free available chlorine (FAC) dosages. The reaction pathways are strongly dependent on pH conditions, while an excessive amount of FAC eliminates BP-4 to the smaller molecules. The initial transformation of BP-4 in chlorination system follows pseudo-first-order kinetics, and its half-lives ranged from 7.48 s to 1.26 × 10(2) s. More importantly, we have observed that the FAC-treated BP-4 aqueous solution might increase the genotoxic potentials due to the generation of chlorinated disinfection by-products. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. Evaluation of dimensional stability of Iralgin and Alginoplast alginates after disinfection by sodium hypochlorite (5.2% with immersion and spraying methods

    Directory of Open Access Journals (Sweden)

    Vojdani M

    2006-01-01

    Full Text Available Background and Aim: Infection control is an integral part of dentistry and dental impressions are considered an important issue in cross contamination. The aim of this study was to investigate the dimensional stability of two irreversible hydrocolloid materials, Alginoplast and Iralgin after disinfection with 5.2% sodium hypochlorite, used with immersion and spraying methods. Material and Methods: In this experimental study, impressions were made of a master mandibular arch (Typodont containing three stainless steel inserts on the occlucal surface of both mandibular first molars and in the lingual surface of the mandibular central incisors, which served as reference marks for making measurements. Two types of irreversible hydrocolloid (Iralgin and Alginoplast were tested. 5.2% sodium hypochlorite was used in two methods of spraying and immersion to disinfect the samples. The control group was not disinfected. Casts were made of type III gypsum. Stone casts were measured with a Nikon profile projector.Kruskall-Wallis and Mann-Witney test were used for statistical analysis using p<0.05 as the limit of significance. Results: Casts prepared from Alginoplast disinfected by spraying method, were 0.38 % larger in anteroposterior and 0.06% smaller in cross arch dimensions, whereas those prepared from Alginoplast immersed in hypochlorite were 0.47% larger in anteroposterior and 0.11% smaller in cross arch dimensions. Casts made from Iralgin were smaller after both methods of disinfecting, (0.01% smaller in anteroposterior and 0.001% smaller in cross-arch dimensions after spraying and 0.04% smaller in anteroposterior and 0.03% smaller in cross-arch dimensions after immersing in sodium hypochlorite. Conclusion: Alginoplast and Iralgin impressions can be immersed or sprayed for disinfection without compromising the accuracy needed for diagnostic and opposing casts, as well as removable partial denture construction.

  16. The Iowa Disinfection Cleaning Project: Opportunities, Successes, and Challenges of a Structured Intervention Program in 56 Hospitals.

    Science.gov (United States)

    Carling, Philip; Herwaldt, Loreen A

    2017-08-01

    OBJECTIVE A diverse group of hospitals in Iowa implemented a program to objectively evaluate and improve the thoroughness of disinfection cleaning of near-patient surfaces. Administrative benefits of, challenges of, and impediments to the program were also evaluated. METHODS We conducted a prospective, quasi-experimental pre-/postintervention trial to improve the thoroughness of terminal room disinfection cleaning. Infection preventionists utilized an objective cleaning performance monitoring system (DAZO) to evaluate the thoroughness of disinfection cleaning (TDC) expressed as a proportion of objects confirmed to have been cleaned (numerator) to objects to be cleaned per hospital policy (denominator)×100. Data analysis, educational interventions, and objective performance feedback were modeled on previously published studies using the same monitoring tool. Programmatic analysis utilized unstructured and structured information from participants irrespective of whether they participated in the process improvement aspects to the program. RESULTS Initially, the overall TDC was 61% in 56 hospitals. Hospitals completing 1 or 2 feedback cycles improved their TDC percentages significantly (P90% for at least 38 months. A survey of infection preventionists found that lack of time and staff turnover were the most common reasons for terminating the study early. CONCLUSION The study confirmed that hospitals using this program can improve their TDC percentages significantly. Hospitals must invest resources to improve cleaning and to sustain their gains. Infect Control Hosp Epidemiol 2017;38:960-965.

  17. Nutritional diversity of agricultural and agro-industrial by-products for ruminant feeding

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    J.A.G. Azevêdo

    2012-10-01

    Full Text Available Fifty-seven by-products were collected from regions throughout Brazil. Chemical composition, in vitro neutral detergent fiber digestibility (IVNDFD, and total digestible nutrients (TDN were determined with the objective of grouping by-products with similar nutritional characteristics. The by-products belonging to group one (G1 presented the highest content of neutral detergent fiber exclusive of ash and nitrogenous compounds [aNDFom(n] and lowest energy content, with 42.5% and 38.8% of IVNDFD and TDN, respectively. A new cluster analysis was carried in order to better characterize G2 by-products, six subgroups (SGs were established (SG1 to SG6. SG1 by-products had the highest and the lowest values for lignin and TDN, respectively. SG2 by-products had the highest aNDFom(n value, with TDN and IVNDFD values greater than 600 and 700g/kg, respectively, and crude protein (CP value below 200g/kg in dry matter (DM. Among all the subgroups, SG3 had the highest TDN (772g/kg and IVNDFD (934g/kg values and the lowest lignin (23g/kg in DM value. The ether extract was what most influenced the hierarchical establishment of residual grouping in SG4. SG5 by-products had the highest concentration of non-fibrous carbohydrate. Different from the other subgroups, SG6 by-products had the highest value of available CP.

  18. Disinfectant choices in veterinary practices, shelters and households : ABCD guidelines on safe and effective disinfection for feline environments

    NARCIS (Netherlands)

    Addie, Diane D; Boucraut-Baralon, Corine; Egberink, Herman; Frymus, Tadeusz; Gruffydd-Jones, Tim; Hartmann, Katrin; Horzinek, Marian C; Hosie, Margaret J; Lloret, Albert; Lutz, Hans; Marsilio, Fulvio; Pennisi, Maria Grazia; Radford, Alan D; Thiry, Etienne; Truyen, Uwe; Möstl, Karin

    OVERVIEW: Regardless of whether a pathogen is viral, bacterial, parasitic, fungal or an emerging unknown, the mainstay of infectious disease control is hygiene, and the cornerstone of good hygiene is effective disinfection. CHALLENGES AND CURRENT CHOICES: Certain pathogens present a challenge to

  19. [Antiseptic effect of compound lysostaphin disinfectant and its preventive effect on infection of artificial dermis after graft on full-thickness skin defect wound in rats].

    Science.gov (United States)

    Jin, J; Zhou, H; Cui, Z C; Wang, L; Luo, P F; Ji, S Z; Hu, X Y; Ma, B; Wang, G Y; Zhu, S H; Xia, Z F

    2018-04-20

    defect wound with a diameter of 20 mm was made on both sides of the spine on the back of each rat. Immediately after injury, the artificial dermis without any treatment was grafted on the wound on left side of the spine (hereinafter referred to as control wound), while the sufficiently soaked artificial dermis with compound lysostaphin disinfectant was grafted on the wound on right side of the spine (hereinafter referred to as disinfectant wound). On PID 3, 7, 14, and 21, the gross condition of wounds of all the surviving rats was observed, and the new infection rates of control wounds and disinfectant wounds were calculated. Then, the rats in the sampling group with corresponding time were killed, and the full-thickness wound tissue containing artificial dermis was collected for quantitative analysis of bacteria. Bacteria content of the uninfected control wounds and that of the uninfected disinfectant wounds were compared. Data were processed with chi-square test and Wilcoxon rank sum test. Results: (1) The MIC of compound lysostaphin disinfectant to standard strains of Staphylococcus aureus , Klebsiella pneumoniae, and Acinetobacter baumannii were 1/32, 1/32, and 1/512 of the original concentration of the disinfectant, respectively, and the MBC were 1/32, 1/16, and 1/512 of the original concentration of the disinfectant, respectively. The percentages of clinical strains of Klebsiella pneumoniae, Acinetobacter baumannii and Staphylococcus aureus with decreased sensitivity to compound lysostaphin disinfectant were 15% (3/20), 20% (4/20), and 10% (2/20), respectively. (2) After being soaked in compound lysostaphin disinfectant for 2 and 4 h, the longest standing time, after which the artificial dermis could form an effective inhibition zone against Klebsiella pneumoniae, Acinetobacter baumannii, and Staphylococcus aureus, were 24, 36, and 48 h respectively, longer than 12, 24, and 24 h of soaking for 5 min and 24, 24, and 36 h of soaking for 1 h. The sufficient soaking

  20. The effectiveness of mimba oil (Azadirachta indica A. Juss spray disinfectant on alginate impression

    Directory of Open Access Journals (Sweden)

    Hanoem EH

    2011-12-01

    Full Text Available Background: Alginate impression contaminated by saliva and blood could potentially cause cross contamination. To prevent this, the impression has to be disinfected by disinfectant liquid, such as mimba oil. Mimba oil (Azadirachta indica A.Juss has some chemical content, such as azadirachtin, which is a phenol group used as antibacterial and antimalaria, nimbolide used as antibacterial and antimalarial, and nimbidin used as antibacterial and antifungal. Purpose: The purpose of this study was to find out the most effective concentration of mimba oil as disinfectant to decrease microorganism colony on alginate impression. Methods: Thirty six samples were taken from 9 respondents. This alginate impression was divided into 4 groups: group 1 sprayed with sterile aquadest (as control group, group 2 sprayed with mimba oil 50% for 30 seconds, group 3 sprayed with mimba oil 75% for 30 seconds, group 4 sprayed with mimba oil 100% for 30 seconds. The microorganism colony was counted by colony counter. The sample data then were analyzed with Kolmogorov-Smirnov test, and was tested with Kruskal Wallis test and Mann Whitney test for further analysis. Results: There was significant difference among each group, p = 0.01 (p < 0.05. Conclusion: In conclusion, usage of 50% concentration of mimba oil as disinfectant is effective to decrease microorganism colony on alginate impression.Latar belakang: Cetakan alginat yang terkontaminasi saliva dan darah dapat berpotensi terjadinya infeksi silang. Untuk mencegah hal tersebut, cetakan didisinfeksi dengan bahan disinfektan cair seperti minyak mimba. Minyak mimba (Azadirachta indica A.Juss memiliki beberapa kandungan kimia, antara lain Azadirachtin yang merupakan kelompok fenol yang memmiliki efek antibakteri dan antimalaria, nimbolide memiliki efek antibakteri dan antimalaria sedangkan nimbidin memiliki efek antibakteri dan antijamur. Tujuan: Tujuan dari penelitian ini adalah untuk menentukan konsentrasi yang paling