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Sample records for volatilization chlorine disinfection

  1. 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.

  2. 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

  3. Data for comparison of chlorine dioxide and chlorine disinfection power in a real dairy wastewater effluent

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    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

  4. Inactivation Effect of Antibiotic-Resistant Gene Using Chlorine Disinfection

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    Takashi Furukawa

    2017-07-01

    Full Text Available The aim of this study was to elucidate the inactivation effects on the antibiotic-resistance gene (vanA of vancomycin-resistant enterococci (VRE using chlorination, a disinfection method widely used in various water treatment facilities. Suspensions of VRE were prepared by adding VRE to phosphate-buffered saline, or the sterilized secondary effluent of a wastewater treatment plant. The inactivation experiments were carried out at several chlorine concentrations and stirring time. Enterococci concentration and presence of vanA were determined. The enterococci concentration decreased as chlorine concentrations and stirring times increased, with more than 7.0 log reduction occurring under the following conditions: 40 min stirring at 0.5 mg Cl2/L, 20 min stirring at 1.0 mg Cl2/L, and 3 min stirring at 3.0 mg Cl2/L. In the inactivation experiment using VRE suspended in secondary effluent, the culturable enterococci required much higher chlorine concentration and longer treatment time for complete disinfection than the cases of suspension of VRE. However, vanA was detected in all chlorinated suspensions of VRE, even in samples where no enterococcal colonies were present on the medium agar plate. The chlorine disinfection was not able to destroy antibiotic-resistance genes, though it can inactivate and decrease bacterial counts of antibiotic-resistant bacteria (ARB. Therefore, it was suggested that remaining ARB and/or antibiotic-resistance gene in inactivated bacterial cells after chlorine disinfection tank could be discharged into water environments.

  5. Electrochemically activated water as an alternative to chlorine for decentralized disinfection

    KAUST Repository

    Ghebremichael, Kebreab A.; Muchelemba, E.; Petruševski, Branislav; Amy, Gary L.

    2011-01-01

    Electrochemically activated (ECA) water is being extensively studied and considered as an alternative to chlorine for disinfection. Some researchers claim that ECA is by and large a chlorine solution, while others claim the presence of reactive

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

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    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.

  7. 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.

  8. Chlorine disinfection of grey water for reuse: effect of organics and particles.

    Science.gov (United States)

    Winward, Gideon P; Avery, Lisa M; Stephenson, Tom; Jefferson, Bruce

    2008-01-01

    Adequate disinfection of grey water prior to reuse is important to prevent the potential transmission of disease-causing microorganisms. Chlorine is a widely utilised disinfectant and as such is a leading contender for disinfection of grey water intended for reuse. This study examined the impact of organics and particles on chlorine disinfection of grey water, measured by total coliform inactivation. The efficacy of disinfection was most closely linked with particle size. Larger particles shielded total coliforms from inactivation and disinfection efficacy decreased with increasing particle size. Blending to extract particle-associated coliforms (PACs) following chlorine disinfection revealed that up to 91% of total coliforms in chlorinated grey water were particle associated. The organic concentration of grey water affected chlorine demand but did not influence the disinfection resistance of total coliforms when a free chlorine residual was maintained. Implications for urban water reuse are discussed and it is recommended that grey water treatment systems target suspended solids removal to ensure removal of PACs prior to disinfection.

  9. Formation of nitrosodimethylamine (NDMA) during chlorine disinfection of wastewater effluents prior to use in irrigation systems.

    Science.gov (United States)

    Pehlivanoglu-Mantas, Elif; Hawley, Elisabeth L; Deeb, Rula A; Sedlak, David L

    2006-01-01

    The probable human carcinogen nitrosodimethylamine (NDMA) is produced when wastewater effluent is disinfected with chlorine. In systems where wastewater effluent is used for landscape or crop irrigation, relatively high chlorine doses (i.e., up to 2,000,mg-min/L) are often used to ensure adequate disinfection and to minimize biofouling in the irrigation system. To assess the formation of NDMA in such systems, samples were collected from several locations in full-scale wastewater treatment systems and their associated irrigation systems. Up to 460 ng/L of NDMA was produced in full-scale systems in which chloramines were formed when wastewater effluent was disinfected with chlorine in the presence of ammonia. Less than 20 ng/L of NDMA was produced in systems that used free chlorine (i.e., HOCl/OCl(-)) for disinfection in the absence of ammonia. The production of NDMA in ammonia-containing systems was correlated with the concentration of NDMA precursors in the wastewater effluent and the overall dose of chlorine applied. Much of the NDMA formation occurred in chlorine contact basins or in storage basins where water that contained chloramines was held after disinfection. When landscape or crop irrigation is practiced with ammonia-containing wastewater effluent, NDMA production can be controlled by use of lower chlorine doses or by application of alternative disinfectants.

  10. Evaluation of possible use of disinfectant based on chlorine dioxide in dairy plant

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    Rakić-Martinez Mira

    2009-01-01

    Full Text Available Poor sanitation of food contact surfaces has been a contributing factor in food borne disease outbreaks, especially those involving Listeria monocytogenes, Salmonella spp., Escherichia coli, Staphylococcus aureus etc. The objectives of this study were therefore to: 1. Determine the efficiency of a disinfectant based on chlorine dioxide in suspension in a closed system in a dairy plant. 2. Evaluate the possibility of disinfection of working surfaces with a disinfectant based on chlorine dioxide. In order to determine the germicidal effect of the disinfectant based on chlorine dioxide by suspension test (BSEN 1276:1997; the following test organisms were used: Listeria monocytogenes, Proteus mirabilis, Escherichia coli, Bacillus cereus, Staphylococcus aureus and Pseudomonas aeruginosa clinical isolate. The corrosive properties of the disinfectant based on chlorine dioxide were tested by IDF 077:1977 standard. The efficacy of this disinfectant was investigated in a closed system in a dairy plant. Results indicated a 100% reduction of >108 cfu/ml L. monocytogenes, E. coli, Proteus mirabilis, Pseudomonas aeruginosa, S. aureus, viable count after 1 minute of exposure to 100 ppm of the disinfectant based on chlorine dioxide and 400 ppm for Bacillus cereus. In the presence of 2% skim milk and 4 % skim milk concentrations of 200 and 250 ppm resulted in 100% reduction in numbers of the five of six test microorganisms, respectively. The spore former, Bacillus cereus is less susceptible to the disinfectant. Therefore, the efficient concentration for 100% reduction in viable count after 1 minute exposure was 500 ppm. The corrosive properties of the disinfectant were not determined. In the case of closed system disinfection in a dairy plant, reduction in viable count after 15 minute exposure to 100 ppm of disinfectant based on chlorine dioxide ranged from 80 to 100%.

  11. Toxic impact of bromide and iodide on drinking water disinfected with chlorine or chloramines.

    Science.gov (United States)

    Yang, Yang; Komaki, Yukako; Kimura, Susana Y; Hu, Hong-Ying; Wagner, Elizabeth D; Mariñas, Benito J; Plewa, Michael J

    2014-10-21

    Disinfectants inactivate pathogens in source water; however, they also react with organic matter and bromide/iodide to form disinfection byproducts (DBPs). Although only a few DBP classes have been systematically analyzed for toxicity, iodinated and brominated DBPs tend to be the most toxic. The objectives of this research were (1) to determine if monochloramine (NH2Cl) disinfection generated drinking water with less toxicity than water disinfected with free chlorine (HOCl) and (2) to determine the impact of added bromide and iodide in conjunction with HOCl or NH2Cl disinfection on mammalian cell cytotoxicity and genomic DNA damage induction. Water disinfected with chlorine was less cytotoxic but more genotoxic than water disinfected with chloramine. For both disinfectants, the addition of Br(-) and I(-) increased cytotoxicity and genotoxicity with a greater response observed with NH2Cl disinfection. Both cytotoxicity and genotoxicity were highly correlated with TOBr and TOI. However, toxicity was weakly and inversely correlated with TOCl. Thus, the forcing agents for cytotoxicity and genotoxicity were the generation of brominated and iodinated DBPs rather than the formation of chlorinated DBPs. Disinfection practices need careful consideration especially when using source waters containing elevated bromide and iodide.

  12. Cross-Resistance of UV- or Chlorine Dioxide-Resistant Echovirus 11 to Other Disinfectants

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    Qingxia Zhong

    2017-10-01

    Full Text Available The emergence of waterborne viruses with resistance to disinfection has been demonstrated in the laboratory and in the environment. Yet, the implications of such resistance for virus control remain obscure. In this study we investigate if viruses with resistance to a given disinfection method exhibit cross-resistance to other disinfectants. Chlorine dioxide (ClO2- or UV-resistant populations of echovirus 11 were exposed to five inactivating treatments (free chlorine, ClO2, UV radiation, sunlight, and heat, and the extent of cross-resistance was determined. The ClO2-resistant population exhibited cross-resistance to free chlorine, but to none of the other inactivating treatments tested. We furthermore demonstrated that ClO2 and free chlorine act by a similar mechanism, in that they mainly inhibit the binding of echovirus 11 to its host cell. As such, viruses with host binding mechanisms that can withstand ClO2 treatment were also better able to withstand oxidation by free chlorine. Conversely, the UV-resistant population was not significantly cross-resistant to any other disinfection treatment. Overall, our results indicate that viruses with resistance to multiple disinfectants exist, but that they can be controlled by inactivating methods that operate by a distinctly different mechanism. We therefore suggest to utilize two disinfection barriers that act by different mechanisms in order to control disinfection-resistant viruses.

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

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    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

  14. Reduced Efficiency of Chlorine Disinfection of Naegleria fowleri in a Drinking Water Distribution Biofilm.

    Science.gov (United States)

    Miller, Haylea C; Wylie, Jason; Dejean, Guillaume; Kaksonen, Anna H; Sutton, David; Braun, Kalan; Puzon, Geoffrey J

    2015-09-15

    Naegleria fowleri associated with biofilm and biological demand water (organic matter suspended in water that consumes disinfectants) sourced from operational drinking water distribution systems (DWDSs) had significantly increased resistance to chlorine disinfection. N. fowleri survived intermittent chlorine dosing of 0.6 mg/L for 7 days in a mixed biofilm from field and laboratory-cultured Escherichia coli strains. However, N. fowleri associated with an attached drinking water distribution biofilm survived more than 30 times (20 mg/L for 3 h) the recommended concentration of chlorine for drinking water. N. fowleri showed considerably more resistance to chlorine when associated with a real field biofilm compared to the mixed laboratory biofilm. This increased resistance is likely due to not only the consumption of disinfectants by the biofilm and the reduced disinfectant penetration into the biofilm but also the composition and microbial community of the biofilm itself. The increased diversity of the field biofilm community likely increased N. fowleri's resistance to chlorine disinfection compared to that of the laboratory-cultured biofilm. Previous research has been conducted in only laboratory scale models of DWDSs and laboratory-cultured biofilms. To the best of our knowledge, this is the first study demonstrating how N. fowleri can persist in a field drinking water distribution biofilm despite chlorination.

  15. Aggregation of Adenovirus 2 in Source Water and Impacts on Disinfection by Chlorine

    Science.gov (United States)

    Cromeans, Theresa L.; Metcalfe, Maureen G.; Humphrey, Charles D.; Hill, Vincent R.

    2016-01-01

    It is generally accepted that viral particles in source water are likely to be found as aggregates attached to other particles. For this reason, it is important to investigate the disinfection efficacy of chlorine on aggregated viruses. A method to produce adenovirus particle aggregation was developed for this study. Negative stain electron microscopy was used to measure aggregation before and after addition of virus particles to surface water at different pH and specific conductance levels. The impact of aggregation on the efficacy of chlorine disinfection was also examined. Disinfection experiments with human adenovirus 2 (HAdV2) in source water were conducted using 0.2 mg/L free chlorine at 5 °C. Aggregation of HAdV2 in source water (≥3 aggregated particles) remained higher at higher specific conductance and pH levels. However, aggregation was highly variable, with the percentage of particles present in aggregates ranging from 43 to 71 %. Upon addition into source water, the aggregation percentage dropped dramatically. On average, chlorination CT values (chlorine concentration in mg/L × time in min) for 3-log10 inactivation of aggregated HAdV2 were up to three times higher than those for dispersed HAdV2, indicating that aggregation reduced the disinfection rate. This information can be used by water utilities and regulators to guide decision making regarding disinfection of viruses in water. PMID:26910058

  16. Comparison of electrochemical method with ozonation, chlorination and monochloramination in drinking water disinfection

    Energy Technology Data Exchange (ETDEWEB)

    Li Hongna, E-mail: lihongna@gmail.com [Department of Environmental Engineering, Peking University, Key Laboratory of Water and Sediment Sciences, Ministry of Education, Beijing 100871 (China); Zhu Xiuping [Department of Environmental Engineering, Peking University, Key Laboratory of Water and Sediment Sciences, Ministry of Education, Beijing 100871 (China); Ni Jinren, E-mail: nijinren@iee.pku.edu.cn [Department of Environmental Engineering, Peking University, Key Laboratory of Water and Sediment Sciences, Ministry of Education, Beijing 100871 (China)

    2011-11-30

    Highlights: > Electrochemical, O{sub 3}, NaClO and NH{sub 2}Cl were compared at respective optimal condition. > Disinfection efficacy was similar for different bacteria in electrolysis. > Harsh Bacillus was inactivated more difficult in O{sub 3}, NaClO and NH{sub 2}Cl system. > Efficient disinfection of electrolysis was attributed to nonselectivity of {center_dot}OH. > Cell surface damage was more obvious in electrochemical process than the others. - Abstract: Electrochemical process in chloride-free electrolytes was proved to be powerful in disinfection due to the strong oxidants produced in the electrolysis and no formation of disinfection byproducts (DBPs). In this study, disinfection experiments were conducted by electrochemical treatment compared with ordinary and advanced methods (ozonation, chlorination and monochloramination), with Escherichia coli (E. coli) K-12, Staphylococcus aureus (S. aureus) A106, Bacillus subtilis (BST) and an isolated Bacillus as the representative microorganisms. Firstly, factor tests were performed on E. coli to obtain the optimal conditions of the four disinfection procedures. At their respective optimal condition, CT (concentration of disinfectant x contact time) value of a 4-log E. coli inactivation was 33.5, 1440, 1575, 1674 mg min L{sup -1} for electrochemical process, ozonation, chlorination and monochloramination, respectively. It was demonstrated that the disinfection availability was in the following order: electrochemical process > ozonation > chlorination > monochloramination, which could be attributed to the hydroxyl radical generated in the electrolysis, with strong oxidizing ability and non-selectivity compared with the other three disinfectants. Moreover, the disinfection efficacy of the four disinfection procedures was compared for four different bacteria. It was found that the disinfection efficacy was similar for the selected four bacteria in electrochemical process, while in the other three treatments

  17. Comparison of electrochemical method with ozonation, chlorination and monochloramination in drinking water disinfection

    International Nuclear Information System (INIS)

    Li Hongna; Zhu Xiuping; Ni Jinren

    2011-01-01

    Highlights: → Electrochemical, O 3 , NaClO and NH 2 Cl were compared at respective optimal condition. → Disinfection efficacy was similar for different bacteria in electrolysis. → Harsh Bacillus was inactivated more difficult in O 3 , NaClO and NH 2 Cl system. → Efficient disinfection of electrolysis was attributed to nonselectivity of ·OH. → Cell surface damage was more obvious in electrochemical process than the others. - Abstract: Electrochemical process in chloride-free electrolytes was proved to be powerful in disinfection due to the strong oxidants produced in the electrolysis and no formation of disinfection byproducts (DBPs). In this study, disinfection experiments were conducted by electrochemical treatment compared with ordinary and advanced methods (ozonation, chlorination and monochloramination), with Escherichia coli (E. coli) K-12, Staphylococcus aureus (S. aureus) A106, Bacillus subtilis (BST) and an isolated Bacillus as the representative microorganisms. Firstly, factor tests were performed on E. coli to obtain the optimal conditions of the four disinfection procedures. At their respective optimal condition, CT (concentration of disinfectant x contact time) value of a 4-log E. coli inactivation was 33.5, 1440, 1575, 1674 mg min L -1 for electrochemical process, ozonation, chlorination and monochloramination, respectively. It was demonstrated that the disinfection availability was in the following order: electrochemical process > ozonation > chlorination > monochloramination, which could be attributed to the hydroxyl radical generated in the electrolysis, with strong oxidizing ability and non-selectivity compared with the other three disinfectants. Moreover, the disinfection efficacy of the four disinfection procedures was compared for four different bacteria. It was found that the disinfection efficacy was similar for the selected four bacteria in electrochemical process, while in the other three treatments inactivation of the two

  18. Disinfection of bore well water with chlorine dioxide/sodium hypochlorite and hydrodynamic cavitation.

    Science.gov (United States)

    Wang, Yifei; Jia, Aiyin; Wu, Yue; Wu, Chunde; Chen, Lijun

    2015-01-01

    The effect of hydrodynamic cavitation (HC) on potable water disinfection of chemicals was investigated. The bore well water was introduced into HC set-up to examine the effect of HC alone and combination of HC and chemicals such as chlorine dioxide and sodium hypochlorite. The effect of inlet pressure and geometrical parameters on disinfection was studied using HC alone and the results showed that increasing inlet pressure and using more and bigger holes of orifice plates can result in a higher disinfection rates. When HC was combined with chemicals, HC can reduce the doses of the chemicals and shorten the time of disinfection. It was also found that the decrease in bacteria concentration followed a first-order kinetic model. As for the experiment of combination of HC and sodium hypochlorite for disinfection, HC not only improves the disinfection rate but also degrades natural organic matter and chloroform. Compared with only sodium hypochlorite disinfection, combined processes get higher disinfection rate and lower production of chloroform, particularly the pretreatment with HC enhances the disinfection rate by 32% and there is a simultaneous reduction in production of chloroform by 39%.

  19. Characterization of unknown iodinated disinfection byproducts during chlorination/chloramination using ultrahigh resolution mass spectrometry

    International Nuclear Information System (INIS)

    Wang, Xin; Wang, Juan; Zhang, Yahe; Shi, Quan; Zhang, Haifeng; Zhang, Yu; Yang, Min

    2016-01-01

    Iodinated disinfection byproducts (I-DBPs), formed from the reaction of disinfectant(s) with organic matter in the presence of iodide in raw water, have recently been focused because of their more cytotoxic and genotoxic properties than their chlorinated or brominated analogues. To date, only a few I-DBPs in drinking water have been identified. In this study, C18 solid phase extraction coupled with electrospray ionization ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS) was used to characterize unknown I-DBPs in chloraminated/chlorinated water spiked with iodide and humic substances. In total, 178 formulas for one-iodine-containing products, 13 formulas for two-iodine-containing products, and 15 formulas for one-chlorine and one-iodine-containing products were detected in the chloraminated water sample, while only 9 formulas for one-iodine-containing products and 6 formulas for one-chlorine and one-iodine-containing products were found in the chlorinated water sample. Most I-DBPs have corresponding chlorine-containing analogues with identical CHO compositions. As indicated by the modified aromaticity index (AI mod ), in the C18 extracts, more than 68% of the I-DBPs have aromatic structures or polycyclic aromatic structures. This result demonstrates that the use of chloramination as an alternative disinfection method may lead to the formation of abundant species of I-DBPs in the presence of iodide. Thus, the suitability of adopting chloramination as an alternative disinfection method should be reevaluated, particularly when iodide is present in raw water. - Highlights: • The formulas of 206 iodinated DBPs in chloraminated drinking water were proposed. • More than 68% of the I-DBPs might have aromatic or polycyclic aromatic structures. • Precursors with high aromaticity is preferential to form iodinated DBPs.

  20. Characterization of unknown iodinated disinfection byproducts during chlorination/chloramination using ultrahigh resolution mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xin; Wang, Juan [State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China); Zhang, Yahe; Shi, Quan [State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Beijing 102249 (China); Zhang, Haifeng; Zhang, Yu [State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China); Yang, Min, E-mail: yangmin@rcees.ac.cn [State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China)

    2016-06-01

    Iodinated disinfection byproducts (I-DBPs), formed from the reaction of disinfectant(s) with organic matter in the presence of iodide in raw water, have recently been focused because of their more cytotoxic and genotoxic properties than their chlorinated or brominated analogues. To date, only a few I-DBPs in drinking water have been identified. In this study, C18 solid phase extraction coupled with electrospray ionization ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS) was used to characterize unknown I-DBPs in chloraminated/chlorinated water spiked with iodide and humic substances. In total, 178 formulas for one-iodine-containing products, 13 formulas for two-iodine-containing products, and 15 formulas for one-chlorine and one-iodine-containing products were detected in the chloraminated water sample, while only 9 formulas for one-iodine-containing products and 6 formulas for one-chlorine and one-iodine-containing products were found in the chlorinated water sample. Most I-DBPs have corresponding chlorine-containing analogues with identical CHO compositions. As indicated by the modified aromaticity index (AI{sub mod}), in the C18 extracts, more than 68% of the I-DBPs have aromatic structures or polycyclic aromatic structures. This result demonstrates that the use of chloramination as an alternative disinfection method may lead to the formation of abundant species of I-DBPs in the presence of iodide. Thus, the suitability of adopting chloramination as an alternative disinfection method should be reevaluated, particularly when iodide is present in raw water. - Highlights: • The formulas of 206 iodinated DBPs in chloraminated drinking water were proposed. • More than 68% of the I-DBPs might have aromatic or polycyclic aromatic structures. • Precursors with high aromaticity is preferential to form iodinated DBPs.

  1. Electrochemically activated water as an alternative to chlorine for decentralized disinfection

    KAUST Repository

    Ghebremichael, Kebreab A.

    2011-06-01

    Electrochemically activated (ECA) water is being extensively studied and considered as an alternative to chlorine for disinfection. Some researchers claim that ECA is by and large a chlorine solution, while others claim the presence of reactive oxygen species such as ozone and hydroxyl radicals in addition to chlorine. This study compares sodium hypochlorite (NaOCl) and ECA in terms of disinfection efficacy, trihalomethanes (THMs) formation, stability and composition. The studies were carried out under different process conditions (pH 5,7 and 9, disinfectant concentrations of 2-5 mg/L and dissolved organic carbon (DOC) concentration of 2-4 mg/L). The results indicated that in the presence of low DOC (<2 mg/L) ECA showed better disinfection efficacy for Escherichia coli inactivation, formed lower THM and had better stability compared with NaOCl at both pH 5 and 7. Stability studies of stock solutions showed that over a period of 30 days, ECA decayed by only 5% while NaOCl decayed by 37.5% at temperatures of 4 °C. In a fresh ECA of 200 mg/L chlorine, about 5.3 mg/L ozone and 36.9 mg/L ClO2 were detected. The study demonstrates that ECA could be a suitable alternative to NaOCl where decentralized production and use are required. © IWA Publishing 2011.

  2. 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.

  3. Limnoithona sinensis as refuge for bacteria: protection from UV radiation and chlorine disinfection in drinking water treatment.

    Science.gov (United States)

    Lin, Tao; Cai, Bo; Chen, Wei

    2014-11-01

    In this study, we tested the potential of Limnoithona sinensis to provide its attached bacteria refuge against disinfection. The experimental results indicated that in water devoid of zooplankton, both UV radiation and chlorine disinfection significantly decreased the viability of free-living bacteria. In the presence of L. sinensis, however, the attached bacteria could survive and rapidly recover from disinfection. This demonstrated that L. sinensis provided protection from external damage to various aquatic bacteria that were attached to its body. The surviving bacteria remained on L. sinensis after disinfection exposure, which enabled a rapid increase in the bacterial population followed by their subsequent release into the surrounding water. Compared with UV radiation, chlorine disinfection was more effective in terms of inactivating attached bacteria. Both UV radiation and chlorine disinfection had little effect in terms of preventing the spread of undesirable bacteria, due to the incomplete inactivation of the bacteria associated with L. sinensis.

  4. Chlorine disinfection of dye wastewater: Implications for a commercial azo dye mixture

    Energy Technology Data Exchange (ETDEWEB)

    Vacchi, Francine Inforcato; Albuquerque, Anjaina Fernandes; Vendemiatti, Josiane Aparecida; Morales, Daniel Alexandre [Faculdade de Tecnologia, Universidade Estadual de Campinas, Limeira, SP, 13484-332 (Brazil); Ormond, Alexandra B.; Freeman, Harold S. [Department of Textile Engineering, Chemistry, and Science, North Carolina State University, Raleigh, NC 27695-8301 (United States); Zocolo, Guilherme Juliao; Zanoni, Maria Valnice Boldrin [Departamento de Quimica Analitica, Universidade Estadual Paulista Julio de Mesquita Filho, Instituto de Quimica de Araraquara, Araraquara, SP 14801-970 (Brazil); Umbuzeiro, Gisela, E-mail: giselau@ft.unicamp.br [Faculdade de Tecnologia, Universidade Estadual de Campinas, Limeira, SP, 13484-332 (Brazil)

    2013-01-01

    Azo dyes, the most widely used family of synthetic dyes, are often employed as colorants in areas such as textiles, plastics, foods/drugs/cosmetics, and electronics. Following their use in industrial applications, azo dyes have been found in effluents and various receiving waters. Chemical treatment of effluents containing azo dyes includes disinfection using chlorine, which can generate compounds of varying eco/genotoxicity. Among the widely known commercial azo dyes for synthetic fibers is C.I. Disperse Red 1. While this dye is known to exist as a complex mixture, reports of eco/genotoxicity involve the purified form. Bearing in mind the potential for adverse synergistic effects arising from exposures to chemical mixtures, the aim of the present study was to characterize the components of commercial Disperse Red 1 and its chlorine-mediated decoloration products and to evaluate their ecotoxicity and mutagenicity. In conducting the present study, Disperse Red 1 was treated with chlorine gas, and the solution obtained was analyzed with the aid of LC-ESI-MS/MS to identify the components present, and then evaluated for ecotoxicity and mutagenicity, using Daphnia similis and Salmonella/microsome assays, respectively. The results of this study indicated that chlorination of Disperse Red 1 produced four chlorinated aromatic compounds as the main products and that the degradation products were more ecotoxic than the parent dye. These results suggest that a disinfection process using chlorine should be avoided for effluents containing hydrophobic azo dyes such commercial Disperse Red 1. -- Highlights: Black-Right-Pointing-Pointer Aqueous solutions of Disperse Red 1 were treated with chlorine. Black-Right-Pointing-Pointer The chlorination products of Disperse Red 1 were identified using LC-ESI-MS/MS. Black-Right-Pointing-Pointer Daphnia and Salmonella/microsome were employed for eco/genotoxicity testing. Black-Right-Pointing-Pointer The chlorinated dye was more mutagenic

  5. Chlorine disinfection of dye wastewater: Implications for a commercial azo dye mixture

    International Nuclear Information System (INIS)

    Vacchi, Francine Inforçato; Albuquerque, Anjaina Fernandes; Vendemiatti, Josiane Aparecida; Morales, Daniel Alexandre; Ormond, Alexandra B.; Freeman, Harold S.; Zocolo, Guilherme Julião; Zanoni, Maria Valnice Boldrin; Umbuzeiro, Gisela

    2013-01-01

    Azo dyes, the most widely used family of synthetic dyes, are often employed as colorants in areas such as textiles, plastics, foods/drugs/cosmetics, and electronics. Following their use in industrial applications, azo dyes have been found in effluents and various receiving waters. Chemical treatment of effluents containing azo dyes includes disinfection using chlorine, which can generate compounds of varying eco/genotoxicity. Among the widely known commercial azo dyes for synthetic fibers is C.I. Disperse Red 1. While this dye is known to exist as a complex mixture, reports of eco/genotoxicity involve the purified form. Bearing in mind the potential for adverse synergistic effects arising from exposures to chemical mixtures, the aim of the present study was to characterize the components of commercial Disperse Red 1 and its chlorine-mediated decoloration products and to evaluate their ecotoxicity and mutagenicity. In conducting the present study, Disperse Red 1 was treated with chlorine gas, and the solution obtained was analyzed with the aid of LC–ESI-MS/MS to identify the components present, and then evaluated for ecotoxicity and mutagenicity, using Daphnia similis and Salmonella/microsome assays, respectively. The results of this study indicated that chlorination of Disperse Red 1 produced four chlorinated aromatic compounds as the main products and that the degradation products were more ecotoxic than the parent dye. These results suggest that a disinfection process using chlorine should be avoided for effluents containing hydrophobic azo dyes such commercial Disperse Red 1. -- Highlights: ► Aqueous solutions of Disperse Red 1 were treated with chlorine. ► The chlorination products of Disperse Red 1 were identified using LC–ESI-MS/MS. ► Daphnia and Salmonella/microsome were employed for eco/genotoxicity testing. ► The chlorinated dye was more mutagenic than the dye itself. ► Chlorination should be avoided in effluents containing azo-dyes.

  6. 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

  7. Chlorine dioxide as a disinfectant for Ralstonia solanacearum control in water, storage and equipment

    Directory of Open Access Journals (Sweden)

    Popović Tatjana

    2016-01-01

    Full Text Available Brown rot or bacterial wilt caused by bacterium Ralstonia solanacearum is the main limiting factor in potato production. Quarantine measures are necessary to avoid spread of disease to disease-free areas. R. solanacearum has been shown to contaminate watercourses from which crop irrigation is then prohibited causing further potential losses in yield and quality. The bacteria also spread via surfaces that diseased seed potatoes come into contact with. This study showed bactericidal activity of chlorine dioxide (CIO2 on R. solanacearum for disinfection of water, surface and equipment. The results showed that CIO2 solution at concentration of 2 ppm at 30 minutes of exposure time had bactericidal effect for disinfection of water. For surface and equipment disinfection, concentration of 50 ppm showed total efficacy at 30 min and 5 sec exposure time, respectively. Results suggest that use of CIO2 as a disinfectant has a potential for control of brown rot pathogen in water, storage and equipment.

  8. Disinfection of herbal spa pool using combined chlorine dioxide and sodium hypochlorite treatment.

    Science.gov (United States)

    Hsu, Ching-Shan; Huang, Da-Ji

    2015-02-01

    The presence of pathogenic microorganisms in public spa pools poses a serious threat to human health. The problem is particularly acute in herbal spas, in which the herbs and microorganisms may interact and produce undesirable consequences. Accordingly, the present study investigated the effectiveness of a combined disinfectant containing chlorine dioxide and sodium hypochlorite in improving the water quality of a public herbal spa in Taiwan. Water samples were collected from the spa pool and laboratory tests were then performed to measure the variation over time of the microorganism content (total CFU and total coliforms) and residual disinfectant content given a single disinfection mode (SDM) with disinfectant concentrations of 5.2 × 10, 6.29 × 10, 7.4 × 10, and 11.4 × 10(-5) N, respectively. Utilizing the experience gained from the laboratory tests, a further series of on-site investigations was performed using three different disinfection modes, namely SDM, 3DM (once every 3 h disinfection mode), and 2DM (once every 2 h disinfection mode). The laboratory results showed that for all four disinfectant concentrations, the CFU concentration reduced for the first 6 h following SDM treatment, but then increased. Moreover, the ANOVA results showed that the sample treated with the highest disinfectant concentration (11.4 × 10(-5) N) exhibited the lowest rate of increase in the CFU concentration. In addition, the on-site test results showed that 3DM and 2DM treatments with disinfectant concentrations in excess of 9.3 × 10 and 5.5 × 10(-5) N, respectively, provided an effective reduction in the total CFU concentration. In conclusion, the experimental results presented in this study provide a useful source of reference for spa businesses seeking to improve the water quality of their spa pools.

  9. Evaluation of disinfection efficiency in pet's hospital by using chlorine dioxide

    Directory of Open Access Journals (Sweden)

    Ching-Shan Hsu

    2016-07-01

    Full Text Available Microbial aerosols could cause various human and animal health problems and their control is becoming a significant scientific and technological topic for consideration. The main objectives of this study were to monitor bioaerosol levels of the pet's hospital and then to perform disinfection efficiency by applying chlorine dioxide. The air quality within these pet's hospitals should satisfy the guidelines specified by the Taiwan Environmental Protection Administration (TEPA. Accordingly, this study performed an experimental investigation into the efficiency of two different gaseous chlorine dioxide (0.3 mg m−3 treatments in disinfecting a local pet's hospital, namely a single, one-off application and a multiple-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. The experimental results found that the average background levels of bacteria and fungi prior to ClO2 disinfection were found to be 2014 ± 1350 and 1002 ± 669 CFU m−3, respectively. A single ClO2 application was found to total disinfected bacteria and fungi concentration levels by as much as 57.3 and 57.6%. By contrast, a multiple-daily ClO2 application was found to total disinfected bacteria and fungi concentration levels by as much as 65.1 and 57.6%. Among the two disinfection methods, the multiple-daily ClO2 application method was found to yield a higher disinfection efficiency for bacteria, i.e., 16.28 ± 0.92%. Thus, using a ClO2 disinfectant to maintain the air quality is of great importance to reduce infectious diseases in the pet's hospital. Therefore, the results suggest that the air quality guidelines prescribed by the TEPA for pet's hospital and other animal facilities can best be achieved by applying chlorine dioxide at regular intervals. The ClO2 aerosol devices can effectively restrain or

  10. Inactivation of antibiotic resistance genes in municipal wastewater effluent by chlorination and sequential UV/chlorination disinfection

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yingying; Zhuang, Yao; Geng, Jinju, E-mail: jjgeng@nju.edu.cn; Ren, Hongqiang, E-mail: hqren@nju.edu.cn; Zhang, Yan; Ding, Lili; Xu, Ke

    2015-04-15

    This study investigated disinfection methods including chlorination, ultraviolet (UV) irradiation and sequential UV/chlorination treatment on the inactivation of antibiotic resistance genes (ARGs). ARGs including sul1, tetX, tetG, intI1, and 16S rRNA genes in municipal wastewater treatment plant (MWTP) effluent were examined. The results indicated a positive correlation between the removal of ARGs and chlorine dosage (p = 0.007–0.014, n = 6),as well as contact time (p = 0.0001, n = 10). Greater free chlorine (FC) dosage leads to higher removal for all the genes and the maximum removal (1.30–1.49 logs) could be achieved at FC dosage of 30 mg L{sup −1}. The transformation kinetic data for ARGs removal (log C{sub 0} / C) followed the second-order reaction kinetic model with FC dosage (R{sup 2} = 0.6829–0.9999) and contact time (R{sup 2} = 0.7353–8634), respectively. Higher ammonia nitrogen (NH{sub 3}–N) concentration was found to lead to lower removal of ARGs at the same chlorine dosage. When the applied Cl{sub 2}:NH{sub 3}–N ratio was over 7.6:1, a significant reduction of ARGs (1.20–1.49 logs) was achieved. By using single UV irradiation, the log removal values of tetX and 16Ss rRNA genes were 0.58 and 0.60, respectively, while other genes were 0.36–0.40 at a fluence of 249.5 mJ cm{sup −2}, which was observed to be less effective than chlorination. With sequential UV/chlorination treatment, 0.006 to 0.31 log synergy values of target genes were observed under different operation parameters. - Highlights: • Chlorine is more effective than UV irradiation in removing ARGs from MWTP effluent. • The chlorination reaction followed the second-order reaction kinetic model. • Higher NH{sub 3}–N contents result in lower ARGs removal in the chlorination process. • FC is more effective than CC on the inactivation of ARGs. • UV irradiation followed by chlorination shows high efficiency in removing ARGs.

  11. 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.

  12. Disinfection byproduct formation from chlorination of pure bacterial cells and pipeline biofilms.

    Science.gov (United States)

    Wang, Jun-Jian; Liu, Xin; Ng, Tsz Wai; Xiao, Jie-Wen; Chow, Alex T; Wong, Po Keung

    2013-05-15

    Disinfection byproduct (DBP) formation is commonly attributed to the reaction between natural organic matters and disinfectants, yet few have considered the contribution from disinfecting bacterial materials - the essential process of water disinfection. Here, we explored the DBP formation from chlorination and chloramination of Escherichia coli and found that most selected DBPs were detectable, including trihalomethanes, haloacetonitriles, chloral hydrate, chloropicrin, and 1,1,1-trichloro-2-propanone. A positive correlation (P = 0.08-0.09) between DBP formation and the log reduction of E. coli implied that breaking down of bacterial cells released precursors for DBP formation. As Pseudomonas aeruginosa is a dominant bacterial species in pipeline biofilms, the DBP formation potentials (DBPFPs) from its planktonic cells and biofilms were characterized. Planktonic cells formed 7-11 times greater trihalomethanes per carbon of those from biofilms but significantly lower (P biofilms on polyvinyl chloride compared to that on galvanized zinc. This study revealed both the in situ disinfection of bacterial planktonic cells in source water and ex situ reaction between biofilms and residual chlorine in pipeline networks as hitherto unknown DBP sources in drinking water. Copyright © 2013 Elsevier Ltd. All rights reserved.

  13. THM reduction on water distribution network with chlorine dioxide as disinfectant

    International Nuclear Information System (INIS)

    Ventura, G.; Gorriz, D.; Pascual, E.; Romero, M.

    2009-01-01

    A disinfectant change on water distribution network, by chlorine dioxide in that case, avoids THM formation. In the other hand it creates big doubts about utilization and analytical determination of another oxidant different to chlorine. Just a need to comply the current legislation points us to make a change as the one mentioned above and carried out in DWTP Rio Verde, being managed by Acosol, where the THM formation is been reduced to 80%, according to the new limit of 100μg/l, along the 200 km of the supply network. (Author) 13 refs.

  14. Disinfection of indoor air microorganisms in stack room of university library using gaseous chlorine dioxide.

    Science.gov (United States)

    Hsu, Ching-Shan; Lu, Ming-Chun; Huang, Da-Ji

    2015-02-01

    As with all indoor public spaces in Taiwan, the stack rooms in public libraries should meet the air quality guidelines laid down by the Taiwan Environmental Protection Administration. Accordingly, utilizing a university library in Taiwan for experimental purposes, this study investigates the efficiency of gaseous chlorine dioxide (ClO2) as a disinfection agent when applied using three different treatment modes, namely a single-daily disinfection mode (SIM), a twice-daily disinfection mode (TWM), and a triple-daily disinfection mode (TRM). For each treatment mode, the ClO2 is applied using an ultrasonic aerosol device and is performed both under natural lighting conditions and under artificial lighting conditions. The indoor air quality is evaluated before and after each treatment session by measuring the bioaerosol levels of bacteria and fungi. The results show that for all three disinfection modes, the application of ClO2 reduces the indoor bacteria and fungi concentrations to levels lower than those specified by the Taiwan EPA (i.e., bacteria <1500 CFU/m(3), fungi <1000 CFU/m(3)), irrespective of the lighting conditions under which the disinfection process is performed. For each disinfection mode, a better disinfection efficiency is obtained under natural lighting conditions since ClO2 readily decomposes under strong luminance levels. Among the three treatment modes, the disinfection efficiencies of the TWM and TRM modes are very similar under natural lighting conditions and are significantly better than that of the SIM mode. Thus, overall, the results suggest that the TWM treatment protocol represents the most cost-effective and efficient method for meeting the indoor air quality requirements of the Taiwan EPA.

  15. 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

  16. Corneal epithelial alterations resulting from use of chlorine-disinfected contact tonometer after myopic photorefractive keratectomy.

    Science.gov (United States)

    Maldonado, M J

    1998-08-01

    This study aimed to describe a previously unreported complication associated with the use of chlorine-disinfected applanation tonometer heads for intraocular pressure measurement after excimer laser photorefractive keratectomy. Two retrospective case reports. Two patients underwent, respectively, a 7-diopter and a 4-diopter myopic excimer laser correction in their first eye 2 weeks apart. Complete epithelial closure of the ablated area was observed by biomicroscopy in the first-week examination. Four weeks after photorefractive keratectomy, a complete ophthalmic examination was performed. Goldmann applanation tonometry was performed bilaterally after thoroughly rinsing and drying the tonometer biprism, which had been immersed regularly in a chlorine 5000-parts per million solution. Slit-lamp examination and corneal topographic surface regularity were measured. A few minutes after applanation tonometry, both patients reported ocular discomfort in the excimer laser-treated eyes, whereas the untreated fellow eyes were painless. Punctate corneal lesions and superficial epithelial cell clumping were present in the first patient's treated eye, predominantly in the inferior aspect of the applanated cornea. Visual inspection showed a normal tonometer tip. In the second patient's treated cornea, a focal epithelial defect was identified biomicroscopically, which corresponded to the steeper region within the ablation zone on the videokeratograph. In this case, crystal deposits were found on the tonometer tip. The epithelial alterations resolved without sequelae in both cases. Disinfecting solutions of chlorine can cause crystal deposit formation on the tonometer head. Applanation tonometry after repeated disinfection with chlorine solutions appears to have the potential for disrupting the epithelial layer of the healing cornea. Covered contact tonometry or noncontact tonometry should be evaluated as alternative methods to chemically disinfected contact tonometry for

  17. Chlorine Dioxide Disinfection in the Use of Individual Water Purification Devices

    Science.gov (United States)

    2006-03-01

    CTs ranging from 1.7-17.6 mg-min/L necessary for 2-log Giardia muris cyst inactivation (reference 23). The SWTR provides the following CT values...reference 3). A comparison of CTs required for a 2-log inactivation for E. Coli bacteria, Poliovirus 1, and Giardia cysts showed Giardia cysts were 2-5...Cryptosporidium oocysts are the most resistant, being 8-16 times more resistant than Giardia cysts (reference 5). Chlorine dioxide’s general disinfection

  18. Reducing the chlorine dioxide demand in final disinfection of drinking water treatment plants using activated carbon.

    Science.gov (United States)

    Sorlini, Sabrina; Biasibetti, Michela; Collivignarelli, Maria Cristina; Crotti, Barbara Marianna

    2015-01-01

    Chlorine dioxide is one of the most widely employed chemicals in the disinfection process of a drinking water treatment plant (DWTP). The aim of this work was to evaluate the influence of the adsorption process with granular activated carbon (GAC) on the chlorine dioxide consumption in final oxidation/disinfection. A first series of tests was performed at the laboratory scale employing water samples collected at the outlet of the DWTP sand filter of Cremona (Italy). The adsorption process in batch conditions with seven different types of GAC was studied. A second series of tests was performed on water samples collected at the outlet of four GAC columns installed at the outlet of the DWTP sand filter. The results showed that the best chlorine dioxide demand (ClO2-D) reduction yields are equal to 60-80% and are achieved in the first 30 min after ClO2 addition, during the first 16 days of the column operation using a mineral, coal-based, mesoporous GAC. Therefore, this carbon removes organic compounds that are more rapidly reactive with ClO2. Moreover, a good correlation was found between the ClO2-D and UV absorbance at wavelength 254 nm using mineral carbons; therefore, the use of a mineral mesoporous GAC is an effective solution to control the high ClO2-D in the disinfection stage of a DWTP.

  19. Peracetic acid disinfection: a feasible alternative to wastewater chlorination.

    Science.gov (United States)

    Rossi, S; Antonelli, M; Mezzanotte, V; Nurizzo, C

    2007-04-01

    The paper summarizes the results of a bench-scale study to evaluate the feasibility of using peracetic acid (PAA) as a substitute for sodium hypochlorite both for discharge into surface water and for agricultural reuse. Trials were carried out with increasing doses (1, 2, 3, 5, 10, and 15 mg/L) and contact times (6, 12, 18, 36, 42, and 54 minutes) to study disinfectant decay and bacterial removal and regrowth, using fecal coliform and Escherichia coli (E. coli) as process efficiency indicators. Peracetic acid decay kinetics was evaluated in tap water and wastewater; in both cases, PAA decays according to first-order kinetics with respect to time, and a correlation was found between PAA oxidative initial consumption and wastewater characteristics. The PAA disinfection efficiency was correlated with operating parameters (active concentration and contact time), testing different kinetic models. Two data groups displaying a different behavior on the basis of initial active concentration ranges (1 to 2 mg/L and 5 to 15 mg/L, respectively) can be outlined. Both groups had a "tailing-off" inactivation curve with respect to time, but the second one showed a greater inactivation rate. Moreover, the effect of contact time was greater at the lower doses. Hom's model, used separately for the two data groups, was found to best fit experimental data, and the disinfectant active concentration appears to be the main factor affecting log-survival ratios. Moreover, the S-model better explains the initial resistance of E. coli, especially at low active concentrations (< 2 mg/L) and short contact times (< 12 minutes). Microbial counts, performed by both traditional methods and flow cytometry, immediately and 5 hours after sample collection (both with or without residual PAA inactivation), showed that no appreciable regrowth took place after 5 hours, neither for coliform group bacteria, nor for total heterotrophic bacteria.

  20. Sequential use of ultraviolet light and chlorine for reclaimed water disinfection

    Institute of Scientific and Technical Information of China (English)

    Xiujuan Wang; Xuexiang Hu; Chun Hu; Dongbin Wei

    2011-01-01

    Several disinfection processes of ultraviolet (UV),chlorine or UV followed by chlorine were investigated in municipal wastewater according to the inactivation of Escherichia coli,Shigella dysenteriae and toxicity formation.The UV inactivation of the tested pathogenic bacteria was not affected by the quality of water.It was found that the inactivated bacteria were obviously reactivated after one day in dark.Fluorescent light irradiation increased the bacteria repair.The increase of UV dosage could cause more damage to bacteria to inhibit bacteria self-repair.No photoreactivation was detected when the UV dose was up to 80 mJ/cm2 for E.coli DH5α,and 23 mJ/cm2 for S.dysenteriae.Nevertheless,sequential use of 8 mJ/cm2 of UV and low concentration of chlorine (1.5mg/L) could effectively inhibit the photoreactivation and inactivate E.coli below the detection limits within seven days.Compared to chlorination alone,the sequential disinfection decreased the genotoxicity of treated wastewater,especially for the sample with high NH3-N concentration.

  1. 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.

  2. 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.

  3. Oxidation of diclofenac by aqueous chlorine dioxide: identification of major disinfection byproducts and toxicity evaluation.

    Science.gov (United States)

    Wang, Yingling; Liu, Haijin; Liu, Guoguang; Xie, Youhai

    2014-03-01

    Diclofenac (DCF), a synthetic non-steroidal anti-inflammatory drug, is one of the most frequently detected pharmaceuticals in the aquatic environment. In this work, the mechanism and toxicity of DCF degradation by ClO2 under simulated water disinfection conditions were investigated. Experimental results indicate that rapid and significant oxidation of DCF occurred within the first few minutes; however, its mineralization process was longer than its degradation process. UPLC-MS and (1)H NMR spectroscopy were performed to identify major disinfection byproducts that were generated in three tentative degradation routes. The two main routes were based on initial decarboxylation of DCF on the aliphatic chain and hydroxylation of the phenylacetic acid moiety at the C-4 position. Subsequently, the formed aldehyde intermediates were the starting point for further multistep degradation involving decarboxylation, hydroxylation, and oxidation reactions of CN bond cleavage. The third route was based on transient preservation of chlorinated derivatives resulting from electrophilic attack by chlorine on the aromatic ring, which similarly underwent CN bond cleavage. Microtox bioassay was employed to evaluate the cytotoxicity of solutions treated by ClO2. The formation of more toxic mid-byproducts during the ClO2 disinfection process poses a potential risk to consumers. Copyright © 2013 Elsevier B.V. All rights reserved.

  4. Effective range of chlorine transport in an aquifer during disinfection of wells: From laboratory experiments to field application

    Science.gov (United States)

    Paufler, S.; Grischek, T.; Adomat, Y.; Herlitzius, J.; Hiller, K.; Metelica, Y.

    2018-04-01

    Microbiological contamination usually leads to erratic operation of drinking water wells and disinfection is required after disasters and sometimes to restore proper well performance for aquifer storage and recovery (ASR) and subsurface iron removal (SIR) wells. This study focused on estimating the fate of chlorine around an infiltration well and improving the knowledge about processes that control the physical extent of the disinfected/affected radius. Closed bottle batch tests revealed low chlorine consumption rates for filter gravel and sand (0.005 mg/g/d) and higher rates for clay (0.030 mg/g/d) as well as natural aquifer material (0.054 mg/g/d). Smaller grain sizes disinfection ability at grain sizes >1 mm, but results in more effective disinfection for very fine material disinfection zone at the example well seems to extend to maximum 3.5 m into the aquifer. Excessive chlorine dosage of >10 mg/l would not further extend the disinfected radius. A preferable way to increase the range of chlorine application is to increase the total infiltrated volume and time. Three approaches are proposed for adapting lab results to actual infiltration wells, that are in principle applicable to any other site.

  5. Chlorinated and Non chlorinated-Volatile Organic Compounds (Vocs) in Drinking Water of Peninsular Malaysia

    International Nuclear Information System (INIS)

    Mohd Pauzi Abdullah; Chian, S.S.

    2011-01-01

    A survey undertaken in Peninsular Malaysia has shown that volatile organic compounds (VOCs), both chlorinated and non-chlorinated, are present in selected drinking water samples. In this study, analyses of VOCs were performed by means of solid phase micro extraction (SPME) with a 100 μm polydimethylsiloxane (PDMS) fibre followed by gas chromatography - mass spectrometry detector (GC-MSD). Samples from different points of the distribution system networks were taken and analysed for 54 VOCs of different chemical families. The results of the study indicated that chloroform constituted the major portion of the VOCs in all samples analysed. In addition to trihalo methanes (THMs), other abundant compounds detected were cis and trans-1,2-dichloroethylene, trichloroethylene, 1,2-dibromoethane, benzene, toluene, ethylbenzene, chlorobenzene, 1,4-dichlorobenzene and 1,2-dichlorobenzene. However, the measured concentrations did not exceed the National Guideline for Drinking Water Quality 2000 in any case. No clear relationship between the status of development of a state in Malaysia to the levels and types of VOCs detected in its drinking water was noted. Nevertheless, the finding of anthropogenic chemicals, even at low concentrations, gave credibility to the viewpoint that improper development and disposal practices threatened the purity of the drinking water. (author)

  6. Toxicity on aquatic organisms exposed to secondary effluent disinfected with chlorine, peracetic acid, ozone and UV radiation.

    Science.gov (United States)

    da Costa, Juliana Berninger; Rodgher, Suzelei; Daniel, Luiz Antonio; Espíndola, Evaldo Luiz Gaeta

    2014-11-01

    The toxic potential of four disinfectant agents (chlorine, ozone, peracetic acid and UV radiation), used in the disinfection of urban wastewater, was evaluated with respect to four aquatic organisms. Disinfection assays were carried out with wastewater from the city of Araraquara (São Paulo State, Brazil), and subsequently, toxicity bioassays were applied in order to verify possible adverse effects to the cladocerans (Ceriodaphnia silvestrii and Daphnia similis), midge larvae Chironomus xanthus and fish (Danio rerio). Under the experimental conditions tested, all the disinfectants were capable of producing harmful effects on the test organisms, except for C. xanthus. The toxicity of the effluent to C. silvestrii was observed to increase significantly as a result of disinfection using 2.5 mg L(-1) chlorine and 29.9 mg L(-1) ozone. Ozonation and chlorination significantly affected the survival of D. similis and D. rerio, causing mortality of 60 to 100 % in comparison to the non-disinfected effluent. In experiments with effluent treated with peracetic acid (PAA) and UV radiation, a statistically significant decrease in survival was only detected for D. rerio. This investigation suggested that the study of the ideal concentrations of disinfectants is a research need for ecologically safe options for the treatment of wastewater.

  7. Impact of chlorinated disinfection on copper corrosion in hot water systems

    Energy Technology Data Exchange (ETDEWEB)

    Montes, J. Castillo [Centre Scientifique et Technique du Bâtiment Nantes, 11 rue Henri Picherit, BP 82341, 44323 Nantes Cedex 03 (France); Laboratoire des Sciences de l’Ingénieur pour l’Environnement, UMR-CNRS 7356, Université de La Rochelle, Avenue Michel Crépeau, 17042 La Rochelle Cedex 1 (France); Hamdani, F. [Laboratoire des Sciences de l’Ingénieur pour l’Environnement, UMR-CNRS 7356, Université de La Rochelle, Avenue Michel Crépeau, 17042 La Rochelle Cedex 1 (France); Creus, J., E-mail: jcreus@univ-lr.fr [Laboratoire des Sciences de l’Ingénieur pour l’Environnement, UMR-CNRS 7356, Université de La Rochelle, Avenue Michel Crépeau, 17042 La Rochelle Cedex 1 (France); Touzain, S. [Laboratoire des Sciences de l’Ingénieur pour l’Environnement, UMR-CNRS 7356, Université de La Rochelle, Avenue Michel Crépeau, 17042 La Rochelle Cedex 1 (France); Correc, O. [Centre Scientifique et Technique du Bâtiment Nantes, 11 rue Henri Picherit, BP 82341, 44323 Nantes Cedex 03 (France)

    2014-09-30

    Highlights: • Impact of disinfectant treatment on the durability of copper pipes. • Synergy between disinfectant concentration and temperature. • Pitting corrosion of copper associated to the corrosion products formation on copper. - Abstract: In France, hot water quality control inside buildings is occasionally ensured by disinfection treatments using temperature increases or addition of sodium hypochlorite (between 0.5 ppm and 1 ppm residual free chlorine). This disinfectant is a strong oxidiser and it could interact with metallic pipes usually used in hot water systems. This work deals with the study of the impact of these treatments on the durability of copper pipes. The objective of this work was to investigate the influence of sodium hypochlorite concentration and temperature on the copper corrosion mechanism. Copper samples were tested under dynamic and static conditions of ageing with sodium hypochlorite solutions ranging from 0 to 100 ppm with temperature at 50 °C and 70 °C. The efficiency of a corrosion inhibitor was investigated in dynamic conditions. Visual observations and analytical analyses of the internal surface of samples was studied at different ageing duration. Corrosion products were characterised by X-ray diffraction and Raman spectroscopy. Temperature and disinfectant were found to considerably affect the copper corrosion mechanism. Surprisingly, the corrosiveness of the solution was higher at lower temperatures. The temperature influences the nature of corrosion products. The protection efficiency is then strongly depend on the nature of the corrosion products formed at the surface of copper samples exposed to the aggressive solutions containing different concentration of disinfectant.

  8. 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.

  9. 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.

  10. Reactions of phenylurea compounds with aqueous chlorine: Implications for herbicide transformation during drinking water disinfection

    International Nuclear Information System (INIS)

    Chusaksri, Sarinma; Sutthivaiyakit, Somyote; Sedlak, David L.; Sutthivaiyakit, Pakawadee

    2012-01-01

    Highlights: ► Mechanism of chlorine reaction with phenylurea compounds has been studied. ► It depends on both chlorinating species and substitutents on the compounds. ► Main products were identified using LC–MS/MS and authentic standards. ► Their transformation under normal drinking water disinfection was predicted. - Abstract: Phenylurea herbicides have been known to contaminate surface waters serving as potable supplies. To access the potential for transformation of these compounds during drinking water treatment, reactions of phenylurea compounds with aqueous chlorine at different pHs were investigated. The effect of substitution at the amino-N on the rate of transformation depends upon pH. Under acidic conditions, all of the phenylurea studied except 3,4-dichloro-3′-N-methylphenylurea (3,4-DCMPU) exhibited third-order kinetics, second order with respect to chlorine and first order with respect to phenylurea, while the reactions of 3,4-DCMPU were first order with respect to both chlorine and the organic compound. Under neutral and alkaline conditions, all compounds exhibited second-order kinetics that was first order with respect to chlorine and the organic compound. Apparent second-order rate constants at 25 °C and pH 7 were 0.76 ± 0.16, 0.52 ± 0.11, 0.39 ± 0.02, 0.27 ± 0.04 and 0.23 ± 0.05 M −1 s −1 for phenylurea, 3, 4-dichlorophenylurea, 3, 4-DCMPU, metoxuron and monuron, respectively. Studies of the chlorination products, monitored by LC/MS/MS, under different pH values indicated the reaction to take place at both N atoms and also at ortho- and para- positions of the phenylurea aromatic group. The main chlorinating species were found to be different in different pH ranges. Under conditions typically encountered in drinking water treatment systems, transformation of these compounds by chlorine will be incomplete.

  11. Application of an electrochemical chlorine-generation system combined with solar energy as appropriate technology for water disinfection.

    Science.gov (United States)

    Choi, Jusol; Park, Chan Gyu; Yoon, Jeyong

    2013-02-01

    Affordable water disinfection is key to reducing the waterborne disease experienced worldwide where resources are limited. A simple electrochemical system that can generate chlorine as a disinfectant from the electrolysis of sodium chloride is an appropriate technology to produce clean water, particularly if driven by solar energy. This study examined the affordability of an electrochemical chlorine generation system using solar energy and developed the necessary design information for its implementation. A two-electrode batch reactor, equipped with commercial IrO(2)-coated electrodes and a solar panel (approximate area 0.2 m(2)), was used to produce chlorine from a 35g/L solution of NaCl. Within 1 h, sufficient chlorine (0.8 g) was generated to produce clean drinking water for about 80 people for 1 day (target microorganism: Escherichia coli; daily drinking water requirement: 2 L per person; chlorine demand: 4 mg/L; solar power: 650 W/m(2) in Seoul, Korea. Small household batteries were demonstrated to be a suitable alternative power source when there is insufficient solar irradiation. Using a 1 m(2) solar panel, the reactor would take only 15 min in Seoul, Korea, or 7 min in the tropics (solar power 1300 W/m(2)), to generate 1 g of chlorine. The solar-powered electrochemical chlorine generation system for which design information is provided here is a simple and affordable way to produce chlorine with which to convert contaminated water into clean drinking water.

  12. Quantification of pathogen inactivation efficacy by free chlorine disinfection of drinking water for QMRA.

    Science.gov (United States)

    Petterson, S R; Stenström, T A

    2015-09-01

    To support the implementation of quantitative microbial risk assessment (QMRA) for managing infectious risks associated with drinking water systems, a simple modeling approach for quantifying Log10 reduction across a free chlorine disinfection contactor was developed. The study was undertaken in three stages: firstly, review of the laboratory studies published in the literature; secondly, development of a conceptual approach to apply the laboratory studies to full-scale conditions; and finally implementation of the calculations for a hypothetical case study system. The developed model explicitly accounted for variability in residence time and pathogen specific chlorine sensitivity. Survival functions were constructed for a range of pathogens relying on the upper bound of the reported data transformed to a common metric. The application of the model within a hypothetical case study demonstrated the importance of accounting for variable residence time in QMRA. While the overall Log10 reduction may appear high, small parcels of water with short residence time can compromise the overall performance of the barrier. While theoretically simple, the approach presented is of great value for undertaking an initial assessment of a full-scale disinfection contactor based on limited site-specific information.

  13. 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.

  14. Passive remediation of chlorinated volatile organic compounds using barometric pumping

    International Nuclear Information System (INIS)

    Rossabi, J.; Looney, B.B.; Dilek, C.A.E.; Riha, B.; Rohay, V.J.

    1993-01-01

    The purpose of the Savannah River Integrated Demonstration Program, sponsored by the Department of Energy, is to demonstrate new subsurface characterization, monitoring, and remediation technologies. The interbedded clay and sand layers at the Integrated Demonstration Site (IDS) are contaminated with chlorinated volatile organic compounds (CVOCs). Characterization studies show that the bulk of the contamination is located in the approximately 40 m thick vadose zone. The most successful strategy for removing contaminants of this type from this environment is vapor extraction alone or in combination with other methods such as air sparging or enhanced bioremediation. Preliminary work at the IDS has indicated that natural pressure differences between surface and subsurface air caused by surface barometric fluctuations can produce enough gas flow to make barometric pumping a viable method for subsurface remediation. Air flow and pressure were measured in wells that are across three stratigraphic intervals in the vadose zone' The subsurface pressures were correlated to surface pressure fluctuations but were damped and lagging in phase corresponding to depth and stratum permeability. Piezometer wells screened at lower elevations exhibited a greater phase lag and damping than wells screened at higher elevations where the pressure wave from barometric fluctuations passes through a smaller number of low permeable layers. The phase lag between surface and subsurface pressures results in significant fluxes through these wells. The resultant air flows through the subsurface impacts CVOC fate and transport. With the appropriate controls (e.g. solenoid valves) a naturally driven vapor extraction system can be implemented requiring negligible operating costs yet capable of a large CVOC removal rate (as much as 1--2 kg/day in each well at the IDS)

  15. 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.

  16. 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...

  17. 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

  18. Impact of wastewater infrastructure upgrades on the urban water cycle: Reduction in halogenated reaction byproducts following conversion from chlorine gas to ultraviolet light disinfection

    International Nuclear Information System (INIS)

    Barber, Larry B.; Hladik, Michelle L.; Vajda, Alan M.; Fitzgerald, Kevin C.; Douville, Chris

    2015-01-01

    The municipal wastewater treatment facility (WWTF) infrastructure of the United States is being upgraded to expand capacity and improve treatment, which provides opportunities to assess the impact of full-scale operational changes on water quality. Many WWTFs disinfect their effluent prior to discharge using chlorine gas, which reacts with natural and synthetic organic matter to form halogenated disinfection byproducts (HDBPs). Because HDBPs are ubiquitous in chlorine-disinfected drinking water and have adverse human health implications, their concentrations are regulated in potable water supplies. Less is known about the formation and occurrence of HDBPs in disinfected WWTF effluents that are discharged to surface waters and become part of the de facto wastewater reuse cycle. This study investigated HDBPs in the urban water cycle from the stream source of the chlorinated municipal tap water that comprises the WWTF inflow, to the final WWTF effluent disinfection process before discharge back to the stream. The impact of conversion from chlorine-gas to low-pressure ultraviolet light (UV) disinfection at a full-scale (68,000 m 3 d −1 design flow) WWTF on HDBP concentrations in the final effluent was assessed, as was transport and attenuation in the receiving stream. Nutrients and trace elements (boron, copper, and uranium) were used to characterize the different urban source waters, and indicated that the pre-upgrade and post-upgrade water chemistry was similar and insensitive to the disinfection process. Chlorinated tap water during the pre-upgrade and post-upgrade samplings contained 11 (mean total concentration = 2.7 μg L −1 ; n = 5) and 10 HDBPs (mean total concentration = 4.5 μg L −1 ), respectively. Under chlorine-gas disinfection conditions 13 HDBPs (mean total concentration = 1.4 μg L −1 ) were detected in the WWTF effluent, whereas under UV disinfection conditions, only one HDBP was detected. The chlorinated WWTF effluent had greater relative

  19. Impact of wastewater infrastructure upgrades on the urban water cycle: Reduction in halogenated reaction byproducts following conversion from chlorine gas to ultraviolet light disinfection

    Energy Technology Data Exchange (ETDEWEB)

    Barber, Larry B. [U.S. Geological Survey, 3215 Marine St., Boulder, CO 80303 (United States); Hladik, Michelle L. [U.S. Geological Survey, 6000 J Street Placer Hall, Sacramento, CA 95819 (United States); Vajda, Alan M. [University of Colorado, Department of Integrative Biology, CB 171, Denver, CO 80217 (United States); Fitzgerald, Kevin C. [U.S. Geological Survey, 3215 Marine St., Boulder, CO 80303 (United States); AECOM, 500 West Jefferson St., Ste. 1600, Louisville, KY 40202 (United States); Douville, Chris [City of Boulder, 4049 75th Street, Boulder, CO 80301 (United States)

    2015-10-01

    The municipal wastewater treatment facility (WWTF) infrastructure of the United States is being upgraded to expand capacity and improve treatment, which provides opportunities to assess the impact of full-scale operational changes on water quality. Many WWTFs disinfect their effluent prior to discharge using chlorine gas, which reacts with natural and synthetic organic matter to form halogenated disinfection byproducts (HDBPs). Because HDBPs are ubiquitous in chlorine-disinfected drinking water and have adverse human health implications, their concentrations are regulated in potable water supplies. Less is known about the formation and occurrence of HDBPs in disinfected WWTF effluents that are discharged to surface waters and become part of the de facto wastewater reuse cycle. This study investigated HDBPs in the urban water cycle from the stream source of the chlorinated municipal tap water that comprises the WWTF inflow, to the final WWTF effluent disinfection process before discharge back to the stream. The impact of conversion from chlorine-gas to low-pressure ultraviolet light (UV) disinfection at a full-scale (68,000 m{sup 3} d{sup −1} design flow) WWTF on HDBP concentrations in the final effluent was assessed, as was transport and attenuation in the receiving stream. Nutrients and trace elements (boron, copper, and uranium) were used to characterize the different urban source waters, and indicated that the pre-upgrade and post-upgrade water chemistry was similar and insensitive to the disinfection process. Chlorinated tap water during the pre-upgrade and post-upgrade samplings contained 11 (mean total concentration = 2.7 μg L{sup −1}; n = 5) and 10 HDBPs (mean total concentration = 4.5 μg L{sup −1}), respectively. Under chlorine-gas disinfection conditions 13 HDBPs (mean total concentration = 1.4 μg L{sup −1}) were detected in the WWTF effluent, whereas under UV disinfection conditions, only one HDBP was detected. The chlorinated WWTF effluent had

  20. Chlorine dioxide oxidation of Escherichia coli in water - A study of the disinfection kinetics and mechanism.

    Science.gov (United States)

    Ofori, Isaac; Maddila, Suresh; Lin, Johnson; Jonnalagadda, Sreekantha B

    2017-06-07

    This study investigated the kinetics and mechanism of chlorine dioxide (ClO 2 ) inactivation of a Gram-negative bacteria Escherichia coli (ATCC 35218) in oxidant demand free (ODF) water in detail as a function of disinfectant concentration (0.5-5.0 mg/L), water pH (6.5-8.5), temperature variations (4-37°C) and bacterial density (10 5 -10 7 cfu/mL). The effects of ClO 2 on bacterial cell morphology, outer membrane permeability, cytoplasmic membrane disruption and intracellular enzymatic activity were also studied to elucidate the mechanism of action on the cells. Increasing temperature and disinfectant concentration were proportional to the rate of cell killing, but efficacy was found to be significantly subdued at 0.5 mg/L and less dependent on the bacterial density. The bactericidal efficiency was higher at alkaline pH of 8 or above as compared to neutral and slightly acidic pH of 7 and 6.5 respectively. The disinfection kinetic curves followed a biphasic pattern of rapid inactivation within the initial 2 min which were followed by a tailing even in the presence of residual biocide. The curves were adequately described by the C avg Hom model. Transmission Electron Microscopy images of the bacteria cells exposed to lethal concentrations of ClO 2 indicated very little observable morphological damage to the outer membranes of the cells. ClO 2 however was found to increase the permeability of the outer and cytoplasmic membranes leading to the leakage of membrane components such as 260 nm absorbing materials and inhibiting the activity of the intracellular enzyme β-D-galactosidase. It is suggested that the disruption of the cytoplasmic membrane and subsequent efflux of intracellular components result in the inactivation of the Gram-negative bacteria.

  1. Comparison of permanganate preoxidation and preozonation on algae containing water: cell integrity, characteristics, and chlorinated disinfection byproduct formation.

    Science.gov (United States)

    Xie, Pengchao; Ma, Jun; Fang, Jingyun; Guan, Yinghong; Yue, Siyang; Li, Xuchun; Chen, Liwei

    2013-12-17

    Aqueous suspensions of Microcystis aeruginosa were preoxidized with either ozone or permanganate and then subjected to chlorination under conditions simulating drinking water purification. The impacts of the two oxidants on the algal cells and on the subsequent production of dissolved organic matter and disinfection byproducts were investigated. Preozonation dramatically increased disinfection byproduct formation during chlorination, especially the formation of haloaldehydes, haloacetonitriles, and halonitromethanes. Preoxidation with permanganate had much less effect on disinfection byproduct formation. Preozonation destroyed algal cell walls and cell membranes to release intracellular organic matter (IOM), and less than 2.0% integrated cells were left after preozonation with the dosage as low as 0.4 mg/L. Preoxidation with permanganate mainly released organic matter adsorbed on the cells' surface without causing any damage to the cells' integrity, so the increase in byproduct formation was much less. More organic nitrogen and lower molecular weight precursors were produced in a dissolved phase after preozonation than permanganate preoxidation, which contributes to the significant increase of disinfection byproducts after preozonation. The results suggest that permanganate is a better choice than ozone for controlling algae derived pollutants and disinfection byproducts.

  2. The effect of inorganic precursors on disinfection byproduct formation during UV-chlorine/chloramine drinking water treatment.

    Science.gov (United States)

    Lyon, Bonnie A; Dotson, Aaron D; Linden, Karl G; Weinberg, Howard S

    2012-10-01

    Ultraviolet (UV) disinfection is being increasingly used in drinking water treatment. It is important to understand how its application to different types of water may influence finished water quality, particularly as anthropogenic activity continues to impact the quality of source waters. The objective of this study was to evaluate the effect of inorganic precursors on the formation of regulated and unregulated disinfection byproducts (DBPs) during UV irradiation of surface waters when combined with chlorination or chloramination. Samples were collected from three drinking water utilities supplied by source waters with varying organic and inorganic precursor content. The filtered samples were treated in the laboratory with a range of UV doses delivered from low pressure (LP, UV output at 253.7 nm) and medium pressure (MP, polychromatic UV output 200-400 nm) mercury lamps followed by chlorination or chloramination, in the presence and absence of additional bromide and nitrate. The regulated trihalomethanes and haloacetic acids were not affected by UV pretreatment at disinfection doses (40-186 mJ/cm²). With higher doses (1000 mJ/cm²), trihalomethane formation was increased 30-40%. While most effects on DBPs were only observed with doses much higher than typically used for UV disinfection, there were some effects on unregulated DBPs at lower doses. In nitrate-spiked samples (1-10 mg N/L), chloropicrin formation doubled and increased three- to six-fold with 40 mJ/cm² MP UV followed by chloramination and chlorination, respectively. Bromopicrin formation was increased in samples containing bromide (0.5-1 mg/L) and nitrate (1-10 mg N/L) when pretreated with LP or MP UV (30-60% with 40 mJ/cm² LP UV and four- to ten-fold increase with 40 mJ/cm² MP UV, after subsequent chlorination). The formation of cyanogen chloride doubled and increased three-fold with MP UV doses of 186 and 1000 mJ/cm², respectively, when followed by chloramination in nitrate-spiked samples but

  3. 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

  4. Disinfection efficacy of chlorine and peracetic acid alone or in combination against Aspergillus spp. and Candida albicans in drinking water.

    Science.gov (United States)

    Sisti, Maurizio; Brandi, Giorgio; De Santi, Mauro; Rinaldi, Laura; Schiavano, Giuditta F

    2012-03-01

    The aim of the present study was to evaluate the fungicidal activity of chlorine and peracetic acid in drinking water against various pathogenic Aspergillus spp. and Candida albicans strains. A. nidulans exhibited the greatest resistance, requiring 10 ppm of chlorine for 30 min contact time for a complete inactivation. Under the same experimental conditions, peracetic acid was even less fungicidal. In this case, A. niger proved to be the most resistant species (50 ppm for 60 min for complete inactivation). All Aspergillus spp. were insensitive to 10 ppm even with extended exposure (>5 h). The combination of chlorine and peracetic acid against Aspergillus spp. did not show synergistic effects except in the case of A. flavus. Complete growth inhibition of C. albicans was observed after about 3 h contact time with 0.2 ppm. C. albicans was less sensitive to peracetic acid. Hence the concentrations of chlorine that are usually present in drinking water distribution systems are ineffective against several Aspergillus spp. and peracetic acid cannot be considered an alternative to chlorine for disinfecting drinking water. The combination of the two biocides is not very effective in eliminating filamentous fungi at the concentrations permitted for drinking water disinfection.

  5. [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.

  6. A Spore Counting Method and Cell Culture Model for Chlorine Disinfection Studies of Encephalitozoon syn. Septata intestinalis

    OpenAIRE

    Wolk, D. M.; Johnson, C. H.; Rice, E. W.; Marshall, M. M.; Grahn, K. F.; Plummer, C. B.; Sterling, C. R.

    2000-01-01

    The microsporidia have recently been recognized as a group of pathogens that have potential for waterborne transmission; however, little is known about the effects of routine disinfection on microsporidian spore viability. In this study, in vitro growth of Encephalitozoon syn. Septata intestinalis, a microsporidium found in the human gut, was used as a model to assess the effect of chlorine on the infectivity and viability of microsporidian spores. Spore inoculum concentrations were determine...

  7. A spore counting method and cell culture model for chlorine disinfection studies of Encephalitozoon syn. Septata intestinalis.

    Science.gov (United States)

    Wolk, D M; Johnson, C H; Rice, E W; Marshall, M M; Grahn, K F; Plummer, C B; Sterling, C R

    2000-04-01

    The microsporidia have recently been recognized as a group of pathogens that have potential for waterborne transmission; however, little is known about the effects of routine disinfection on microsporidian spore viability. In this study, in vitro growth of Encephalitozoon syn. Septata intestinalis, a microsporidium found in the human gut, was used as a model to assess the effect of chlorine on the infectivity and viability of microsporidian spores. Spore inoculum concentrations were determined by using spectrophotometric measurements (percent transmittance at 625 nm) and by traditional hemacytometer counting. To determine quantitative dose-response data for spore infectivity, we optimized a rabbit kidney cell culture system in 24-well plates, which facilitated calculation of a 50% tissue culture infective dose (TCID(50)) and a minimal infective dose (MID) for E. intestinalis. The TCID(50) is a quantitative measure of infectivity and growth and is the number of organisms that must be present to infect 50% of the cell culture wells tested. The MID is as a measure of a system's permissiveness to infection and a measure of spore infectivity. A standardized MID and a standardized TCID(50) have not been reported previously for any microsporidian species. Both types of doses are reported in this paper, and the values were used to evaluate the effects of chlorine disinfection on the in vitro growth of microsporidia. Spores were treated with chlorine at concentrations of 0, 1, 2, 5, and 10 mg/liter. The exposure times ranged from 0 to 80 min at 25 degrees C and pH 7. MID data for E. intestinalis were compared before and after chlorine disinfection. A 3-log reduction (99.9% inhibition) in the E. intestinalis MID was observed at a chlorine concentration of 2 mg/liter after a minimum exposure time of 16 min. The log(10) reduction results based on percent transmittance-derived spore counts were equivalent to the results based on hemacytometer-derived spore counts. Our data

  8. Development of an online biosensor for in situ monitoring of chlorine dioxide gas disinfection efficacy

    Energy Technology Data Exchange (ETDEWEB)

    Del Busto-Ramos, M.; Budzik, M.; Corvalan, C.; Morgan, M.; Nivens, D.; Applegate, B. [Purdue Univ., West Lafayette, IN (United States). Dept. of Food Science; Turco, R. [Purdue Univ., West Lafayette, IN (United States). Dept. of Agronomy

    2008-03-15

    A prototype bioluminescence-based biosensor was designed and constructed to evaluate the antimicrobial efficacy of chlorine dioxide (ClO{sub 2}) gas under various treatment conditions. The biosensor consisted of a bioluminescent bioreporter (Pseudomonas fluorescens 5RL), an optical transducer (photomultiplier tube), and a light-tight chamber housing, the bioreporter and the transducer. The bioluminescent recombinant P. fluorescens 5RL in the biosensor allowed for online monitoring of bioluminescence during ClO{sub 2} gas disinfection. Experiments were performed to evaluate the effects of the two key physical parameters associated with ClO{sub 2} disinfection: relative humidity (40, 60, 80%) and ClO{sub 2} gas concentration (0.5, 1.0, 1.6, 2.1 mg/l) on the bioreporter. Results showed that increasing concentrations of ClO{sub 2} gas corresponded to a faster decrease in luminescence. The rates of luminescence decrease from P. fluorescens 5RL, and the log reduction time (LRT, time required to obtain 1-log reduction in luminescence) were calculated for each treatment tested. The LRT values of luminescence were 103, 78, 53, and 35 s for 0.5, 1.0, 1.6, and 2.1 mg/l of ClO{sub 2} gas treatment, respectively, at 78% relative humidity. The gas concentration which caused a tenfold change in LRT (z value) for luminescence of P. fluorescens 5RL was 3.4 mg/l of ClO{sub 2}. The prototype biosensor showed potential for many applications, such as monitoring real-time microbial inactivation and understanding parameters that influence the efficacy of gaseous decontamination procedures. (orig.)

  9. Chlorination of antimony and its volatilization treatment of waste antimony-uranium composite oxide catalyst

    International Nuclear Information System (INIS)

    Sawada, K.; Enokida, Y.

    2011-01-01

    For the waste antimony-uranium composite oxide catalyst, the chlorination of antimony and its volatilization treatment were proposed, and evaluated using hydrogen chloride gas at 873-1173 K. During the treatment, the weight loss of the composite oxide sample, which resulted from the volatilization of antimony, was confirmed. An X-ray diffraction analysis showed that uranium oxide, U 3 O 8 , was formed during the reaction. After the treatment at 1173 K for 1 h, almost all the uranium contained in the waste catalyst was dissolved by a 3 M nitric acid solution at 353 K within 10 min, although that of the non-treated catalyst was less than 0.1%. It was found that the chlorination and volatilization treatment was effective to separate antimony from the composite oxide catalyst and change uranium into its removable form. (orig.)

  10. 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.

  11. Presence of Trihalomethanes in ready-to-eat vegetables disinfected with chlorine.

    Science.gov (United States)

    Coroneo, Valentina; Carraro, Valentina; Marras, Barbara; Marrucci, Alessandro; Succa, Sara; Meloni, Barbara; Pinna, Antonella; Angioni, Alberto; Sanna, Adriana; Schintu, Marco

    2017-12-01

    Trihalomethanes (THMs) - CHCl 3 , CHCl 2 Br, CHClBr 2 and CHBr 3 - are drinking water disinfection by-products (DBPs). These compounds can also be absorbed by different types of foods, including ready-to-eat (RTE) fresh vegetables. The potential absorption of THMs during washing of RTE vegetables could pose a potential risk to consumers' health. The concentration of THMs in the water used in the manufacturing process of these products shall not exceed the limit of 100 or 80 µgL -1 according to European Union (EU) and United States legislation, respectively. By contrast, there is little information about the presence of such compounds in the final product. This study evaluated the concentration of THMs in different types of RTE vegetables (carrots, iceberg lettuce, lettuce, mixed salad, parsley, parsley and garlic, rocket salad, valerian) after washing with chlorinated water. In the 115 samples analysed, the average value of total THMs was equal to 76.7 ng g -1 . Chloroform was the THM present in the largest percentage in all the RTE vegetables. These results show that the process of washing RTE vegetables should be optimised in order to reduce the risk for consumers associated with the presence of DBPs.

  12. UV disinfection and flocculation-chlorination sachets to reduce hepatitis E virus in drinking water.

    Science.gov (United States)

    Guerrero-Latorre, Laura; Gonzales-Gustavson, Eloy; Hundesa, Ayalkibet; Sommer, Regina; Rosina, Girones

    2016-07-01

    Hepatitis E Virus (HEV) is a major cause of waterborne outbreaks in areas with poor sanitation. As safe water supplies are the keystone for preventing HEV outbreaks, data on the efficacy of disinfection treatments are urgently needed. Here, we evaluated the ability of UV radiation and flocculation-chlorination sachets (FCSs) to reduce HEV in water matrices. The HEV-p6-kernow strain was replicated in the HepG2/C3A cell line, and we quantified genome number using qRT-PCR and infectivity using an immunofluorescence assay (IFA). UV irradiation tests using low-pressure radiation showed inactivation kinetics for HEV of 99.99% with a UV fluence of 232J/m(2) (IC 95%, 195,02-269,18). Moreover, the FCSs preparations significantly reduced viral concentrations in both water matrices, although the inactivation results were under the baseline of reduction (4.5 LRV) proposed by WHO guidelines. Copyright © 2016 Elsevier GmbH. All rights reserved.

  13. Application of Highly Purified Electrolyzed Chlorine Dioxide for Tilapia Fillet Disinfection

    Directory of Open Access Journals (Sweden)

    Chen-Hsing Yu

    2014-01-01

    Full Text Available This research aimed to develop an electrolysis method to generate high-concentration chlorine dioxide (ClO2 for tilapia fillet disinfection. The designed generator produced up to 3500 ppm of ClO2 at up to 99% purity. Tilapia fillets were soaked in a 400 ppm ClO2 solution for 5, 10, and 25 min. Results show that total plate counts of tilapia, respectively, decreased by 5.72 to 3.23, 2.10, and 1.09 log CFU/g. In addition, a 200 ppm ClO2 solution eliminated coliform bacteria and Escherichia coli in 5 min with shaking treatment. Furthermore, ClO2 and trihalomethanes (THMs residuals on tilapia fillets were analyzed by GC/MS and were nondetectable (GC-MS detection limit was 0.12 ppb. The results conform to Taiwan’s environmental protection regulations and act governing food sanitation.

  14. Impact of wastewater infrastructure upgrades on the urban water cycle: Reduction in halogenated reaction byproducts following conversion from chlorine gas to ultraviolet light disinfection

    Science.gov (United States)

    Barber, Larry B.; Hladik, Michelle; Vajda, Alan M.; Fitzgerald, Kevin C.; Douville, Chris

    2015-01-01

    The municipal wastewater treatment facility (WWTF) infrastructure of the United States is being upgraded to expand capacity and improve treatment, which provides opportunities to assess the impact of full-scale operational changes on water quality. Many WWTFs disinfect their effluent prior to discharge using chlorine gas, which reacts with natural and synthetic organic matter to form halogenated disinfection byproducts (HDBPs). Because HDBPs are ubiquitous in chlorine-disinfected drinking water and have adverse human health implications, their concentrations are regulated in potable water supplies. Less is known about the formation and occurrence of HDBPs in disinfected WWTF effluents that are discharged to surface waters and become part of the de facto wastewater reuse cycle. This study investigated HDBPs in the urban water cycle from the stream source of the chlorinated municipal tap water that comprises the WWTF inflow, to the final WWTF effluent disinfection process before discharge back to the stream. The impact of conversion from chlorine-gas to low-pressure ultraviolet light (UV) disinfection at a full-scale (68,000 m3 d−1 design flow) WWTF on HDBP concentrations in the final effluent was assessed, as was transport and attenuation in the receiving stream. Nutrients and trace elements (boron, copper, and uranium) were used to characterize the different urban source waters, and indicated that the pre-upgrade and post-upgrade water chemistry was similar and insensitive to the disinfection process. Chlorinated tap water during the pre-upgrade and post-upgrade samplings contained 11 (mean total concentration = 2.7 μg L−1; n=5) and 10 HDBPs (mean total concentration = 4.5 μg L−1), respectively. Under chlorine-gas disinfection conditions 13 HDBPs (mean total concentration = 1.4 μg L−1) were detected in the WWTF effluent, whereas under UV disinfection conditions, only one HDBP was detected. The chlorinated WWTF effluent had greater relative

  15. Identification and characterization of phenylacetonitrile as a nitrogenous disinfection byproduct derived from chlorination of phenylalanine in drinking water.

    Science.gov (United States)

    Ma, Xiaoyan; Deng, Jing; Feng, Jiao; Shanaiah, Narasimhamurthy; Smiley, Elizabeth; Dietrich, Andrea M

    2016-10-01

    Unregulated disinfection byproducts (DBPs), including nitrogenous disinfection byproducts (N-DBPs), originating from chlorination of the precursor amino acid phenylalanine in aqueous systems, were identified in laboratory reactions and distributed tap. The major N-DBP identified was phenylacetonitrile, and minor DBPs of benzyl chloride, phenylacetaldehyde, 2-chlorobenzyl cyanide, and 2, 6-diphenylpyridine were also formed. Phenylacetonitrile was generated through decarboxylation, dechlorination and/or hydrolysis processes. With an aromatic structure, phenylacetonitrile has an unpleasant odor of various descriptors and an odor threshold concentration of 0.2 ppt-v as measured through gas chromatography-olfactometry. The half-life of phenylacetonitrile in reagent water and chlorinated water at 19 °C were 121 h and 792 h, respectively. The occurrence of phenylacetonitrile as an N-DBP in tap water was investigated for the first time; the results revealed that μg/L concentrations were present in nine different distributed drinking waters in China and the United States. Phenylacetonitrile deteriorates the aesthetic quality of drinking water and may present risk due to its prolonged existence in drinking water, especially in the presence of residual chlorine. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Disinfection of Penicillium-infected Wheat Seed by Gaseous Chlorine Dioxide

    Directory of Open Access Journals (Sweden)

    Young-ah Jeon

    2015-06-01

    Full Text Available Seeds of wheat (Triticum aestivum L. cv. Olgeurumil were infected with Penicillium sp. at mean infection rate of 83%. Penicillium sp. was detected in endosperm with bran but not in embryo. Gaseous chlorine dioxide (ClO2 effectively inhibited growth of Penicillium sp. at concentration of 5 to 20 mg/ml. As treatment duration was extended from 1 to 3 h, growth of Penicillium sp. was completely suppressed even at 10 mg/ml. There was no significant reduction in the incidence of Penicillium sp. at 30% relative humidity (RH. However, the incidence of Penicillium sp. was 27.7% at 50% RH, further those were 3.5% and 0.2% at 70% and 80% RH, respectively. Seed germination was not affected by ClO2 treatment at all the RH conditions. Water-soaked seeds (30% seed moisture content showed a drastic reduction in the incidence of Penicillium sp. when treated at more than 10 mg/ml of ClO2. The incidences of Penicillium sp. were 3.3, 1.8 and 1.2% at 10, 15 and 20 mg/ml, respectively. The incidence of Penicillium sp. in dry seeds with 9.7% seed moisture content did not reduce when treated with 5 and 10 mg/ml at 50% RH although it tended to decrease as ClO2 concentration increased to 20 mg/ml. Seed germination was not affected by ClO2 treatment at the tested concentrations. These results indicated that gaseous ClO2 was effective disinfectant to wheat seeds infected with Penicillium sp. and that the effectiveness of ClO2 strongly increased when moisture content around or inside of the seed was increased.

  17. 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.

  18. 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

  19. 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.

  20. 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.

  1. 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.

  2. Comparative study on the efficiency of peracetic acid and chlorine dioxide at low doses in the disinfection of urban wastewaters.

    Science.gov (United States)

    De Luca, Giovanna; Sacchetti, Rossella; Zanetti, Franca; Leoni, Erica

    2008-01-01

    A comparison was made between the efficiency of low doses of peracetic acid (PAA: 1.5 mg/l) and chlorine dioxide (ClO(2): 1.5 and 2.0 mg/l) in the disinfection of secondary effluents of a wastewater treatment plant. Peracetic acid was seen to be more active than chlorine dioxide and less influenced by the organic content of the waste. Both PAA and ClO(2) (2.0 mg/l) lead to a higher reduction in total and faecal coliforms and E. coli than in phages (somatic coliphages and F-specific RNA bacteriophages) and enterococci. Detection of faecal coliforms and E. coli should therefore be accompanied by a search for these more resistant microorganisms when assessing the conformity of wastewater for irrigation use, or for discharge into surface waters. Coliphages are also considered suitable indicators of the presence of enteric viruses. Although the application of low doses of both disinfectants offers advantages in terms of costs and produces not significant quantities of byproducts, it is not sufficient to obtain wastewater suitable for irrigation according to the Italian norms (E. coli < 10/100 ml in 80 % of samples and <100/100 ml in the remaining samples). Around 65 % of the samples, however, presented concentrations of E. coli lower than the limit of 5,000/100 ml established by Italian norms for discharge into surface waters.

  3. 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...

  4. A New On-Line Detecting Apparatus of the Residual Chlorine in Disinfectant for Fresh-Cut Vegetables

    Science.gov (United States)

    Hu, Chao; Su, Shu-Qiang; Li, Bao-Guo; Liu, Meng-Fang

    With the fast development of modern food and beverage industry, fresh-cut vegetables have wider application than before. During the process of sterilization in fresh-cut vegetables, the concentration of chloric disinfectant is usually so high that the common sensor can't be used directly on the product line. In order to solve this problem, we have invented a new detecting apparatus which could detect high concentration of chloric disinfectant directly. In this paper, the working principle, main monitor indicators, application and technical creations of the on-line apparatus have been discussed, and we also carried on the experimental analysis for its performance. The actual demands in factory could be met when the detecting flux is 2L/min, the dilution ratio is 15 and input amount of the disinfectant is 200ml per time, the max of the detecting deviation achieves ±4.8ppm(mg/L). The main detecting range of residual chlorine is 0~300ppm.

  5. The placing of the disinfection stage in a reclamation plant to reduce haloform formation

    Energy Technology Data Exchange (ETDEWEB)

    Hart, O O

    1979-10-01

    Chlorination of water containing organic matter leads to the formation of various volatile halogenated hydrocarbons (VHH). Various process configurations of a water reclamation plant were studied to determine the best position of the primary disinfection stage in the plant to achieve the greatest possible reduction of haloform concentration in the water distribution system. The pros and cons of ozone and chlorine as disinfectants were also investigated. Experiment methodology is explained. Results indicate that breakpoint chlorination ahead of two active carbon adsorption stages is the preferred process sequence and disinfectant to assure the lowest possible VHH production in the distribution system. (3 diagrams, 1 drawing, 8 graphs, 54 references, 2 tables)

  6. Detection, formation and occurrence of 13 new polar phenolic chlorinated and brominated disinfection byproducts in drinking water.

    Science.gov (United States)

    Pan, Yang; Wang, Ying; Li, Aimin; Xu, Bin; Xian, Qiming; Shuang, Chendong; Shi, Peng; Zhou, Qing

    2017-04-01

    Recently, 13 new polar phenolic chlorinated and brominated disinfection byproducts (Cl- and Br-DBPs) were identified and quantified in simulated chlorinated drinking water by adopting product ion scan, precursor ion scan, and multiple reaction monitoring (MRM) analyses using ultra performance liquid chromatography/electrospray ionization-triple quadrupole mass spectrometry (UPLC/ESI-tqMS). The 13 new DBPs have been drawing increasing concern not only because they possess significantly higher growth inhibition, developmental toxicity, and chronic cytotoxicity than commonly known aliphatic DBPs, but also because they act as intermediate DBPs that can decompose to form the U.S. EPA regulated DBPs. In this study, through MS parameter optimization of the UPLC/ESI-tqMS MRM analysis, the instrument detection and quantitation limits of the 13 new DBPs were substantially lowered to 0.42-6.44 and 1.35-16.51 μg/L, respectively. The total levels of the 13 new DBPs formed in chlorination were much higher than those formed in chloramination within a contact time of 3 d. In chlorination, the 13 new DBPs formed quickly and decomposed rapidly, and their total concentration kept on decreasing with contact time. In chloramination, the levels of the dominant species (i.e., trihalo-phenols) firstly increased and then decreased with contact time, whereas the levels of the other new DBPs were relatively low and kept on increasing with contact time. An increasing of pH from 6.0 to 9.0 decreased the formation of the 13 new DBPs by 57.8% and 62.3% in chlorination and chloramination, respectively. Gallic acid was found to be present in various simulated and real source water samples and was demonstrated to be a precursor of the 13 new DBPs with elucidated formation pathways. Furthermore, 12 of the 13 new DBPs were detected in 16 tap water samples obtained from major cities in East China, at total levels from 9.5 to 329.8 ng/L. The concentrations of the new DBPs were higher in samples

  7. Distribution of nonionic organic compounds (highly volatile chlorinated hydrocarbons) in the unsaturated zone

    Energy Technology Data Exchange (ETDEWEB)

    Grathwohl, P.

    1988-01-01

    Nonpolar pollutants, e.g. highly volatile chlorinated hydrocarbons (HVCH) are more or less equally distributed among all three soil phases (solids, water, air) in the unsaturated zone. The sorption of HVCH on soil solids depends on the amount and type of organic matter in the soil. For wet material an additional sorption on mineral surfaces can be neglected, since all possible sites for sorption are occupied by water. Provided the partition-coefficients or sorption-constants are known the contamination of the whole system can be evaluated from the pollutant concentration in the soil air; in addition it is possible to estimate a groundwater risk.

  8. 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...

  9. Chlorinated volatile organic compounds (Cl-VOCs) in environment - sources, potential human health impacts, and current remediation technologies.

    Science.gov (United States)

    Huang, Binbin; Lei, Chao; Wei, Chaohai; Zeng, Guangming

    2014-10-01

    Chlorinated volatile organic compounds (Cl-VOCs), including polychloromethanes, polychloroethanes and polychloroethylenes, are widely used as solvents, degreasing agents and a variety of commercial products. These compounds belong to a group of ubiquitous contaminants that can be found in contaminated soil, air and any kind of fluvial mediums such as groundwater, rivers and lakes. This review presents a summary of the research concerning the production levels and sources of Cl-VOCs, their potential impacts on human health as well as state-of-the-art remediation technologies. Important sources of Cl-VOCs principally include the emissions from industrial processes, the consumption of Cl-VOC-containing products, the disinfection process, as well as improper storage and disposal methods. Human exposure to Cl-VOCs can occur through different routes, including ingestion, inhalation and dermal contact. The toxicological impacts of these compounds have been carefully assessed, and the results demonstrate the potential associations of cancer incidence with exposure to Cl-VOCs. Most Cl-VOCs thus have been listed as priority pollutants by the Ministry of Environmental Protection (MEP) of China, Environmental Protection Agency of the U.S. (U.S. EPA) and European Commission (EC), and are under close monitor and strict control. Yet, more efforts will be put into the epidemiological studies for the risk of human exposure to Cl-VOCs and the exposure level measurements in contaminated sites in the future. State-of-the-art remediation technologies for Cl-VOCs employ non-destructive methods and destructive methods (e.g. thermal incineration, phytoremediation, biodegradation, advanced oxidation processes (AOPs) and reductive dechlorination), whose advantages, drawbacks and future developments are thoroughly discussed in the later sections. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. Volatility literature of chlorine, iodine, cesium, strontium, technetium, and rhenium; technetium and rhenium volatility testing

    International Nuclear Information System (INIS)

    Langowski, M.H.; Darab, J.G.; Smith, P.A.

    1996-03-01

    A literature review pertaining to the volatilization of Sr, Cs, Tc (and its surrogate Re), Cl, I and other related species during the vitrification of Hanford Low Level Waste (LLW) streams has been performed and the relevant information summarized. For many of these species, the chemistry which occurs in solution prior to the waste stream entering the melter is important in dictating their loss at higher temperatures. In addition, the interactive effects between the species being lost was found to be important. A review of the chemistries of Tc and Re was also performed. It was suggested that Re would indeed act as an excellent surrogate for Tc in non-radioactive materials testing. Experimental results on Tc and Re loss from sodium aluminoborosilicate melts of temperatures ranging from 900--1350 degrees C performed at PNL are reported and confirm that Re behaves in a nearly identical manner to that of technetium

  11. Degradation of clofibric acid in UV/chlorine disinfection process: kinetics, reactive species contribution and pathways.

    Science.gov (United States)

    Tang, Yuqing; Shi, Xueting; Liu, Yongze; Feng, Li; Zhang, Liqiu

    2018-02-01

    As a potential endocrine disruptor, clofibric acid (CA) was investigated in this study for its degradation kinetics and pathways in UV/chlorine process. The results showed that CA in both UV photolysis and UV/chlorine processes could be degraded via pseudo-first-order kinetics, while it almost could not be degraded in the dark chlorination process. The observed rate constant ( k obs ) in UV photolysis was 0.0078 min -1, and increased to 0.0107 min -1 combining with 0.1 mM chlorine. The k obs increased to 0.0447 min -1 with further increasing the chlorine dosage from 0.1 to 1.0 mM, and reached a plateau at higher dosage (greater than 1.0 mM). The higher k obs was obtained at acid solution rather than basic solution. Moreover, the calculated contributions of radical species to k obs indicated that the HO• contributed significantly to CA degradation in acidic conditions, while the reactive chlorine species and UV direct photolysis dominated in neutral and basic solution. The degradation of CA was slightly inhibited in the presence of [Formula: see text] (1 ∼ 50 mM), barely affected by the presence of Cl - (1 ∼ 200 mM) and greatly suppressed by humic acid (0 ∼ 5 mg l -1 ). Thirteen main degradation intermediates and three degradation pathways of CA were identified during UV/chlorine process.

  12. Chlorine

    Science.gov (United States)

    ... your clothing, rapidly wash your entire body with soap and water, and get medical care as quickly as possible. Removing and disposing of clothing: Quickly take off clothing that has liquid chlorine on it. Any clothing that has to ...

  13. Plant stress activated by chlorine from disinfectants prepared on the base of sodium hypochlorite

    Directory of Open Access Journals (Sweden)

    Fargašová Agáta

    2017-12-01

    Full Text Available In this study, the phytotoxicity of disinfectants prepared on the base of sodium hypochlorite was determined. For our tests two commercial products, Savo and Dom Amor, as well as 10% NaClO solution were used. While Savo contained only NaClO, Dom Amor contained NaClO and earthworm enzymes. Products on the base of NaClO are used in households for cleaning and disinfection of floors, furniture, sanitary and kitchen equipment. Savo may be used for the disinfection of drinking waters as well. Products with NaClO are also used for bacteria, algae and pathogens reduction in irrigation waters. As a subject, young seedlings of mustard Sinapis alba L. were used for the study of chronic toxicity. The observed parameters of the inhibition of roots and shoots growth, dry (DM and fresh (FM mass as well as photosynthetic pigments production (chlorophyll a, b, carotenoids and water content in the plants were determined. The results point out that Dom Amor was the most toxic for S. alba seedlings growth and the rank order of the FAC contents for both plant parts was arranged as: Dom Amor > Savo > NaClO. All disinfectants reduced the DM and FM of roots; however, they stimulated biomass production in the shoots. On the basis of the obtained results it could be concluded, that disinfectants stimulated photosynthetic pigments production and reduced water content mainly in the roots. Dom Amor did not significantly reduced the water content in the shoots and for this parameter the following rank orders of inhibition for roots and shoots could be arranged as NaClO > Dom Amor > Savo and NaClO > Savo > Dom Amor, respectively. All commercial products increased chlorophyll a (Chla and the carotenoids (Car content in the shoots. As significant increase was confirmed first for Chla whose content in the presence of NaClO at concentration 24 mL/L overextended that in the control by 3.5 times. The rank orders of stimulation for Chla and Car were NaClO > Savo > Dom Amor and Dom

  14. Study on inactivation kinetics of hepatitis A virus and enteroviruses with peracetic acid and chlorine. New ICC/PCR method to assess disinfection effectiveness.

    Science.gov (United States)

    Bigliardi, L; Sansebastiano, G

    2006-06-01

    The virucidal activity of chlorine-compounds was studied using hepatitis A virus (HAV) and Poliovirus 2 and comparing the disinfectant efficiency of peracetic acid. HAV presented a higher resistance to HClO than Poliovirus did. With ClO2 the inactivation times of HAV were markedly shorter. A comparison between these data and those resulting from the kinetics with peracetic acid (PA) showed that PA is less effective than chlorine. As a preliminary to future research, the PCR-test integrated with cell-cultures was experimentally introduced for a quick evaluation of the HAV-infectiveness, with the aim of possible application in the field of disinfection and of viruses-isolation from environmental and food samples.

  15. Photodecomposition of iodinated contrast media and subsequent formation of toxic iodinated moieties during final disinfection with chlorinated oxidants.

    Science.gov (United States)

    Allard, Sébastien; Criquet, Justine; Prunier, Anaïs; Falantin, Cécilia; Le Person, Annaïg; Yat-Man Tang, Janet; Croué, Jean-Philippe

    2016-10-15

    Large amount of iodinated contrast media (ICM) are found in natural waters (up to μg.L(-)(1) levels) due to their worldwide use in medical imaging and their poor removal by conventional wastewater treatment. Synthetic water samples containing different ICM and natural organic matter (NOM) extracts were subjected to UV254 irradiation followed by the addition of chlorine (HOCl) or chloramine (NH2Cl) to simulate final disinfection. In this study, two new quantum yields were determined for diatrizoic acid (0.071 mol.Einstein(-1)) and iotalamic acid (0.038 mol.Einstein(-1)) while values for iopromide (IOP) (0.039 mol.Einstein(-1)), iopamidol (0.034 mol.Einstein(-1)) and iohexol (0.041 mol.Einstein(-1)) were consistent with published data. The photodegradation of IOP led to an increasing release of iodide with increasing UV doses. Iodide is oxidized to hypoiodous acid (HOI) either by HOCl or NH2Cl. In presence of NOM, the addition of oxidant increased the formation of iodinated disinfection by-products (I-DBPs). On one hand, when the concentration of HOCl was increased, the formation of I-DBPs decreased since HOI was converted to iodate. On the other hand, when NH2Cl was used the formation of I-DBPs was constant for all concentration since HOI reacted only with NOM to form I-DBPs. Increasing the NOM concentration has two effects, it decreased the photodegradation of IOP by screening effect but it increased the number of reactive sites available for reaction with HOI. For experiments carried out with HOCl, increasing the NOM concentration led to a lower formation of I-DBPs since less IOP are photodegraded and iodate are formed. For NH2Cl the lower photodegradation of IOP is compensated by the higher amount of NOM reactive sites, therefore, I-DBPs concentrations were constant for all NOM concentrations. 7 different NOM extracts were tested and almost no differences in IOP degradation and I-DBPs formation was observed. Similar behaviour was observed for the 5 ICM

  16. On site sodium hypochlorite generation using electro chlorination. Disinfection of potable waste in small communities; Produccion in situ de NaClO, mediante electrocloracion. Aplicaciona la desinfeccion de agua de consumo en pequenas comunidades

    Energy Technology Data Exchange (ETDEWEB)

    Valero, F.; Todra, F.; Gomez, J. L.

    2008-07-01

    This works deals with the experience of ATLL in the re chlorination of its distribution system.Besides security problems that present the disinfection using chlorine in local tanks near the houses, in some cases, the irregular consumption leads to new problems related with maintenance and management of the system. To improve the process, ATLL has installed some on site electro chlorination systems to generate sodium hypochlorite (0,8%) from salt, at request. (Author) 8 refs.

  17. Alternative methods for chlorination

    Energy Technology Data Exchange (ETDEWEB)

    Fiessinger, F; Rook, J J; Duguet, J P

    1985-12-01

    Existing disinfectants are oxidative agents which all present negative effects on subsequent treatment processes. None of them has decisive advantages over chlorine, although chlorine-dioxide and chloramines might at times be preferable. Optimum treatment practices will improve the removal of organic precursors before final disinfection which could then consist in a light chlorine addition. A philosophy of radical change in water treatment technology encompassing physical treatment without chemicals such as membrane filtration, solid disinfectants is presented.

  18. Virucidal Activity of Fogged Chlorine Dioxide- and Hydrogen Peroxide-Based Disinfectants against Human Norovirus and Its Surrogate, Feline Calicivirus, on Hard-to-Reach Surfaces

    Directory of Open Access Journals (Sweden)

    Naim Montazeri

    2017-06-01

    Full Text Available Human norovirus (NoV is the leading cause of foodborne illnesses in the United States. Norovirus is shed in high numbers in the feces and vomitous of infected individuals. Contact surfaces contaminated with bodily fluids harboring infectious virus particles serve as vehicles for pathogen transmission. Environmental stability of NoV and its resistance to many conventional disinfectants necessitate effective inactivation strategies to control the spread of virus. We investigated the efficacy of two commercial disinfectants, hydrogen peroxide (7.5% and a chlorine dioxide (0.2%-surfactant-based product using a fogging delivery system against human NoV GI.6 and GII.4 Sydney strains as well as the cultivable surrogate, feline calicivirus (FCV dried on stainless steel coupons. Log10 reductions in human NoV and FCV were calculated utilizing RNase RT-qPCR and infectivity (plaque assay, respectively. An improved antiviral activity of hydrogen peroxide as a function of disinfectant formulation concentration in the atmosphere was observed against both GII.4 and FCV. At 12.4 ml/m3, hydrogen peroxide achieved a respective 2.5 ± 0.1 and 2.7 ± 0.3 log10 reduction in GI.6 and GII.4 NoV genome copies, and a 4.3 ± 0.1 log10 reduction in infectious FCV within 5 min. At the same disinfectant formulation concentration, chlorine dioxide-surfactant-based product resulted in a respective 1.7 ± 0.2, 0.6 ± 0.0, and 2.4 ± 0.2 log10 reduction in GI.6, GII.4, and FCV within 10 min; however, increasing the disinfectant formulation concentration to 15.9 ml/m3 negatively impacted its efficacy. Fogging uniformly delivered the disinfectants throughout the room, and effectively decontaminated viruses on hard-to-reach surfaces. Hydrogen peroxide delivered by fog showed promising virucidal activity against FCV by meeting the United States EPA 4-log10 reduction criteria for an anti-noroviral disinfectant; however, fogged chlorine dioxide-surfactant-based product did not achieve

  19. Chlorine and Sulfur Volatiles from in Situ Measurements of Martian Surface Materials

    Science.gov (United States)

    Clark, B. C.

    2014-12-01

    A sentinel discovery by the first in situ measurements on Mars was the high sulfur and chlorine content of global-wide soils. A variety of circumstantial evidence led to the conclusion that soil S is in the form of sulfate, and the Cl is probably chloride. An early hypothesis states that these volatiles are emitted as gases from magmas, and quickly react with dust, soil, and exposed rocks. Subsequent determination that SNC meteorites are also samples of the martian crust revealed a significantly higher S content, as sulfide, than terrestrial igneous rocks but substantially less than in soils. The ensuing wet chemical analyses by the high-latitude Phoenix mission discovered not only chloride but also perchlorate and possibly chlorate. MSL data now also implicate perchlorate at low latitudes. Gaseous interactions may have produced amorphous material on grain surfaces without forming stoichiometric salts. Yet, when exposed to liquid water, Phoenix samples released electrolytes, indicating that the soils have not been leached by rain or fresh groundwater. Sulfate occurrences at many locations on Mars, as well as some chloride enrichments, have now been discovered by remote sensing, Landed missions have discovered Cl-enrichments and ferric, Mg, Ca and more complex sulfates as duricrust, subsurface soil horizons, sandstone evaporites, and rock coatings - most of which cannot be detected from orbit. Salt-forming volatiles affect habitability wherever they are in physical contact: physicochemical parameters (ionic strength, freezing point, water activity); S is an essential element for terrestrial organisms; perchlorate is an oxidant which can degrade some organics but also can be utilized as an energy source; the entire valence range of S-compounds has been exploited by diverse microbiota on Earth. Whether such salt-induced conditions are "extremes" of habitability depends on the relative abundance of liquid H2O.

  20. 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...

  1. N-nitrosamine formation by monochloramine, free chlorine, and peracetic acid disinfection with presence of amine precursors in drinking water system.

    Science.gov (United States)

    West, Danielle M; Wu, Qihua; Donovan, Ariel; Shi, Honglan; Ma, Yinfa; Jiang, Hua; Wang, Jianmin

    2016-06-01

    In this study, the formation of eight N-nitrosamines, N-nitrosodimethylamine (NDMA), N-nitrosodiethylamine, N-nitrosomethylamine, N-nitrosodi-n-propylamine, N-nitrosodi-n-butylamine, N-Nitrosopiperidine, N-Nitrosopyrrolidine, N-Nitrosomorpholine, were systematically evaluated with respect to seven N-nitrosamine precursors (dimethylamine, trimethylamine, 3-(dimethylaminomethyl)indole, 4-dimethylaminoantipyrine, ethylmethylamine, diethylamine, dipropylamine) and three disinfectants (monochloramine, free chlorine, peracetic acid) under variable dosages, exposure times, and pH in a drinking water system. Without the presence of the seven selected N-nitrosamine precursors N-nitrosamine formation was not observed under any tested condition except very low levels of N-Nitrosopyrrolidine under some conditions. With selected N-nitrosamine precursors present N-nitrosamines formed at different levels under different conditions. The highest N-nitrosamine formation was NDMA with a maximum concentration of 1180 ng/L by monochloramine disinfection with precursors present; much lower levels of N-nitrosamines were formed by free chlorine disinfection; and no detectable level of N-nitrosamines were observed by peracetic acid disinfection except low level of N-Nitrosodi-n-propylamine under some conditions. NDMA formation was not affected by pH while four other N-nitrosamine formations were slightly affected by sample pH tested between 7 and 9, with formation decreasing with increasing pH. Monochloramine exposure time study displayed fast formation of N-nitrosamines, largely formed in four hours of exposure and maximized after seven days. This was a systematic study on the N-nitrosamine formation with the seven major N-nitrosamine precursors presence and absence under different conditions, including peracetic acid disinfection which has not been studied elsewhere. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Volatile Short-chain Chlorinated Hydrocarbons in the Groundwater of the City of Zagreb

    Directory of Open Access Journals (Sweden)

    Marijanović-Rajčić, M.

    2008-01-01

    Full Text Available The aim of the study was to assess the quality of the groundwater sampled from private wells and the public water-supply system in terms of estimating the contamination caused by short-chain chlorinated hydrocarbons, as well as to estimate the exposure of the citizens dwelling in different suburbs to these pollutants of their drinking water (Fig. 1. The aim of the study was also to determine which suburb is supplied through the public water-supply system with water originating from the Sašnak spring that is contaminated with volatile chlorinated short-chain hydrocarbons.Drinking water samples were taken from 3 private wells and 1 public water-supply system situated in 3 Zagreb suburbs - Pešćenica, Trnje, and Trešnjevka. The sampling was carried out during 2003 and was undertaken on a seasonal basis. Short-chain chlorinated hydrocarbons - 1,1,1-trichloroethane, carbon tetrachloride, 1,1,2-trichloroethene and 1,1,2,2-tetrachloroethene - were determined by gas chromatography, following "liquid-liquid extraction" in pentane. For that purpose, we applied the gas chromatograph equipped with an electron-capture detector, thermo-programmable operations, and a suitable capillary column. The technique applied was that of split-injection.The groundwater of the City of Zagreb was found to be contaminated with volatile chlorinated hydrocarbons. The concentration level of 1,1,1-trichloroethane, determined in most of the samples, was found to be low (Fig. 2. On the other hand, 1,1,2-trichloroethene was present in all samples in concentrations of about 1 µg l-1- (Fig. 3. Only the drinking water samples taken from private wells in the suburb of Trnje contained somewhat higher mass concentrations of 1,1,1-trichloroethane, with the peak value of 19.03 µg l-1, measured in the winter season. In the samples taken from private wells in Trnje, the mass concentrations of 1,1,2,2-tetrachloroethene rangedfrom 15.30 µg l-1 to 18.65 µg l-1, as measured in autumn

  3. Microbial quality of swimming pool water with treatment without disinfection, with ultrafiltration, with UV-based treatment and with chlorination

    NARCIS (Netherlands)

    Keuten, M.G.A.; Peters, M.C.F.M.; van Dijk, J.C.; van Loosdrecht, Mark C.M.; Rietveld, L.C.

    2017-01-01

    Swimming pools are traditionally disinfected with a residual disinfectant such as sodium hypochlorite. Nowadays, swimming water without a residual disinfectant is increasingly popular, as can be seen by the growing number of (natural) swimming ponds (Weilandt 2015), but health risks for bathers do

  4. Comparison of the disinfection efficacy of chlorine-based products for inactivation of viral indicators and pathogenic bacteria in produce wash water.

    Science.gov (United States)

    Chaidez, Cristobal; Moreno, Maria; Rubio, Werner; Angulo, Miguel; Valdez, Benigno

    2003-09-01

    Outbreaks of pathogenic bacteria infections associated with the consumption of fresh produce has occurred with increased frequency in recent years. This study was undertaken to determine the efficacy of three commonly used disinfectants in packing-houses of Culiacan, Mexico (sodium hypochlorite [NaOCl], trichlor-s-triazinetrione [TST] and thrichlormelamine [TCM]) for inactivation of viral indicators and pathogenic bacteria inoculated onto produce wash water. Each microbial challenge consisted of 2 L of water containing approximately 8 log10 bacterial CFU ml(-1), and 8 log10 viral PFU ml(-1) treated with 100 and 300 mg l(-1) of total chlorine with modified turbidity. Water samples were taken after 2 min of contact with chlorine-based products and assayed for the particular microorganisms. TST and NaOCl were found to effectively reduce for bacterial pathogens and viral indicators 8 log10 and 7 log10, respectively (alpha=0.05). The highest inactivation rate was observed when the turbidity was low and the disinfectant was applied at 300 mg l(-1). TCM did not show effective results when compared with the TST and NaOCl (Pturbidity created by the organic and inorganic material present in the water tanks carried by the fresh produce may affect the efficacy of the chlorine-based products.

  5. Comparison of the toxicity of wastewater disinfected with the alternatives to chlorination by bioassay using seaweed (Porphyra yezoensis conchospores); Kaiso (susabinori gai hoshi) wo mochiita seibutsu kentei ni yoru toshi gesui no enso daitai shodoku shorisui no dokusei hikaku

    Energy Technology Data Exchange (ETDEWEB)

    Takami, T.; Maruyama, T.; Suzuki, Y. [Miyazaki University, Miyazaki (Japan). Faculty of Engineering; Kaiga, N. [Toshiba Corp., Tokyo (Japan); Miura, A. [Aomori University, Aomori (Japan). Faculty of Engineering

    1998-11-10

    The technique now in use for disinfecting municipal sewerage is the free chlorine method, and the free chlorine reacts with ammonia in the treated water for the formation of NH4Cl. The resultant compound is strongly toxic and harms aquatic organisms, this creating a knotty problem to solve. In this report, a bioassay utilizing Porphyra yezoensis conchospores is performed, and the toxicity reducing effect is discussed of the seaweed on water specimens disinfected by free chlorine, chlorine dioxide, ozone, and ultraviolet rays. Porphyra yezoensis is easy to acquire, and the bioassay evaluates the toxicity of the water specimens by evaluating the survival rate of conchospores discharged by free-living conchoceles and the rate of inhibited sprouting. The outcome is summarized below. The injection dose required for inactivating 99.9% of the groups of coli bacteria in the treated water and the trend of fluctuations in the concentration level are obtained. No inhibition of conchospore sprouting occurs even with the addition of 100% of treated water in the chlorine-disinfected specimen or chlorine dioxide-disinfected specimen. 19 refs., 8 figs., 2 tabs.

  6. Evaluation of current operating standards for chlorine dioxide in disinfection of dump tank and flume for fresh tomatoes.

    Science.gov (United States)

    Tomás-Callejas, Alejandro; López-Velasco, Gabriela; Valadez, Angela M; Sbodio, Adrian; Artés-Hernández, Francisco; Danyluk, Michelle D; Suslow, Trevor V

    2012-02-01

    Standard postharvest unit operations that rely on copious water contact, such as fruit unloading and washing, approach the criteria for a true critical control point in fresh tomato production. Performance data for approved sanitizers that reflect commercial systems are needed to set standards for audit compliance. This study was conducted to evaluate the efficacy of chlorine dioxide (ClO(2)) for water disinfection as an objective assessment of recent industry-adopted standards for dump tank and flume management in fresh tomato packing operations. On-site assessments were conducted during eight temporally distinct shifts in two Florida packinghouses and one California packinghouse. Microbiological analyses of incoming and washed fruit and dump and flume system water were evaluated. Water temperature, pH, turbidity, conductivity, and oxidation-reduction potential (ORP) were monitored. Reduction in populations of mesophilic and coliform bacteria on fruit was not significant, and populations were significantly higher (P Turbidity and conductivity increased with loads of incoming tomatoes. Water temperature varied during daily operations, but pH and ORP mostly remained constant. The industry standard positive temperature differential of 5.5°C between water and fruit pulp was not maintained in tanks during the full daily operation. ORP values were significantly higher in the flume than in the dump tank. A positive correlation was found between ORP and temperature, and negative correlations were found between ORP and turbidity, total mesophilic bacteria, and coliforms. This study provides in-plant data indicating that ClO(2) can be an effective sanitizer in flume and spray-wash systems, but current operational limitations restrict its performance in dump tanks. Under current conditions, ClO(2) alone is unlikely to allow the fresh tomato industry to meet its microbiological quality goals under typical commercial conditions.

  7. Site-specific probabilistic ecological risk assessment of a volatile chlorinated hydrocarbon-contaminated tidal estuary.

    Science.gov (United States)

    Hunt, James; Birch, Gavin; Warne, Michael St J

    2010-05-01

    Groundwater contaminated with volatile chlorinated hydrocarbons (VCHs) was identified as discharging to Penrhyn Estuary, an intertidal embayment of Botany Bay, New South Wales, Australia. A screening-level hazard assessment of surface water in Penrhyn Estuary identified an unacceptable hazard to marine organisms posed by VCHs. Given the limitations of hazard assessments, the present study conducted a higher-tier, quantitative probabilistic risk assessment using the joint probability curve (JPC) method that accounted for variability in exposure and toxicity profiles to quantify risk (delta). Risk was assessed for 24 scenarios, including four areas of the estuary based on three exposure scenarios (low tide, high tide, and both low and high tides) and two toxicity scenarios (chronic no-observed-effect concentrations [NOEC] and 50% effect concentrations [EC50]). Risk (delta) was greater at low tide than at high tide and varied throughout the tidal cycle. Spatial distributions of risk in the estuary were similar using both NOEC and EC50 data. The exposure scenario including data combined from both tides was considered the most accurate representation of the ecological risk in the estuary. When assessing risk using data across both tides, the greatest risk was identified in the Springvale tributary (delta=25%)-closest to the source area-followed by the inner estuary (delta=4%) and the Floodvale tributary (delta=2%), with the lowest risk in the outer estuary (delta=0.1%), farthest from the source area. Going from the screening level ecological risk assessment (ERA) to the probabilistic ERA changed the risk from unacceptable to acceptable in 50% of exposure scenarios in two of the four areas within the estuary. The probabilistic ERA provided a more realistic assessment of risk than the screening-level hazard assessment. Copyright (c) 2010 SETAC.

  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. 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.

  10. Sequential disinfection of E. coli O157:H7 on shredded lettuce leaves by aqueous chlorine dioxide, ozonated water, and thyme essential oil

    Science.gov (United States)

    Singh, Nepal; Singh, Rakesh K.; Bhunia, Arun K.; Stroshine, Richard L.; Simon, James E.

    2001-03-01

    There have been numerous studies on effectiveness of different sanitizers for microbial inactivation. However, results obtained from different studies indicate that microorganism cannot be easily removed from fresh cut vegetables because of puncture and cut surfaces with varying surface topographies. In this study, three step disinfection approach was evaluated for inactivation of E. coli O157:H7 on shredded lettuce leaves. Sequential application of thyme oil, ozonated water, and aqueous chlorine dioxide was evaluated in which thyme oil was applied first followed by ozonated water and aqueous chlorine dioxide. Shredded lettuce leaves inoculated with cocktail culture of E. coli O157:H7 (C7927, EDL 933 and 204 P), were washed with ozonated water (15 mg/l for 10min), aqueous chlorine dioxide (10 mg/l,for 10min) and thyme oil suspension (0.1%, v/v for 5min). Washing of lettuce leaves with ozonated water, chlorine dioxide and thyme oil suspension resulted in 0.44, 1.20, and 1.46 log reduction (log10 cfu/g), respectively. However, the sequential treatment achieved approximately 3.13 log reductions (log10 cfu/g). These results demonstrate the efficacy of sequential treatments in decontaminating shredded lettuce leaves containing E. coli O157:H7.

  11. Formation and Occurrence of N-Chloro-2,2-dichloroacetamide, a Previously Overlooked Nitrogenous Disinfection Byproduct in Chlorinated Drinking Waters.

    Science.gov (United States)

    Yu, Yun; Reckhow, David A

    2017-02-07

    Haloacetamides (HAMs) are a class of newly identified nitrogenous disinfection byproducts (N-DBPs) whose occurrence in drinking waters has recently been reported in several DBP surveys. As the most prominent HAM species, it is commonly acknowledged that 2,2-dichloroacetamide (DCAM) is mainly generated from dichloroacetonitrile (DCAN) hydrolysis because the concentrations of these two compounds are often well correlated. Instead of DCAM, a previously unreported N-DBP, N-chloro-2,2-dichloroacetamide (N-Cl-DCAM), was confirmed in this study as the actual DCAN degradation product in chlorinated drinking waters. It is suspected that N-Cl-DCAM has been erroneously identified as DCAM, because its nitrogen-bound chlorine is readily reduced by most commonly used quenching agents. This hypothesis is supported by kinetic studies that indicate almost instantaneous N-chlorination of DCAM even at low chlorine residuals. Therefore, it is unlikely that DCAM can persist as a long-lived DCAN decomposition product in systems using free chlorine as a residual disinfectant. Instead, chlorination of DCAM will lead to the formation of an equal amount of N-Cl-DCAM by forming a hydrogen bond between hypochlorite oxygen and amino hydrogen. Alternatively, N-Cl-DCAM can be produced directly from DCAN chlorination via nucleophilic addition of hypochlorite on the nitrile carbon. Due to its relatively low pK a value, N-Cl-DCAM tends to deprotonate under typical drinking water pH conditions, and the anionic form of N-Cl-DCAM was found to be very stable in the absence of chlorine. N-Cl-DCAM can, however, undergo acid-catalyzed decomposition to form the corresponding dichloroacetic acid (DCAA) when chlorine is present, although those acidic conditions that favor N-Cl-DCAM degradation are generally atypical for finished drinking waters. For these reasons, N-Cl-DCAM is predicted to have very long half-lives in most distribution systems that use free chlorine. Furthermore, an analytical method using

  12. 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.

  13. Simultaneous counter-flow of chlorinated volatile organic compounds across the saturated-unsaturated interface region of an aquifer.

    Science.gov (United States)

    Ronen, Daniel; Lev-Wiener, Hagit; Graber, Ellen R; Dahan, Ofer; Weisbrod, Noam

    2010-04-01

    Concentrations of chlorinated volatile organic compounds (Cl-VOCs) at the saturated-unsaturated interface region (SUIR; depth of approximately 18m) of a sandy phreatic aquifer were measured in two monitoring wells located 25m apart. The concentrations of the Cl-VOCs obtained above and below the water table along a 413-day period are interpreted to depict variable, simultaneous and independent movement of trichlorothene, tetrachloroethene, 1,1-dichloroethene, cis-1,2-dichloroethene, 1,1,1-trichloroethane, chloroform and 1,1-dichloroethane vapors in opposite directions across the SUIR. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

  14. Development of pyrometallurgical partitioning technology of long-lived nuclides. Recovery of volatile chlorides for chlorination process using molten salt trap. 1

    International Nuclear Information System (INIS)

    Hijikata, Takatoshi; Nakamura, Kyosei; Kurata, Masateru; Konagaya, Hideaki

    1997-01-01

    The dry process for partitioning of long-lived nuclides from high level radioactive waste has been developed. One of the subjects for development of this process is the recovering of the volatilization of chlorides for the chlorination process. We proposed that the volatile chlorides were recovered by the molten salt trap. We researched the behavior of volatile chlorides (ferric chloride, zirconium tetra-chloride and molybdenum pent-chloride) in LiCl-KCl eutectic salt. In this result, the volatile rate of these chlorides was slower than the volatile rate of undissolved chlorides in LiCl-KCl eutectic salt. Also, we make a prototype of molten salt trap for recovering the volatile chlorides and tested the performance of this experimental apparatus and recovering ratio of volatile chlorides. This trap has a good performance of recovering volatile chlorides. (author)

  15. 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

  16. Four groups of new aromatic halogenated disinfection byproducts: effect of bromide concentration on their formation and speciation in chlorinated drinking water.

    Science.gov (United States)

    Pan, Yang; Zhang, Xiangru

    2013-02-05

    Bromide is naturally present in source waters worldwide. Chlorination of drinking water can generate a variety of chlorinated and brominated disinfection byproducts (DBPs). Although substantial efforts have been made to examine the effect of bromide concentration on the formation and speciation of halogenated DBPs, almost all previous studies have focused on trihalomethanes and haloacetic acids. Given that about 50% of total organic halogen formed in chlorination remains unknown, it is still unclear how bromide concentration affects the formation and speciation of the new/unknown halogenated DBPs. In this study, chlorinated drinking water samples with different bromide concentrations were prepared, and a novel approach-precursor ion scan using ultra performance liquid chromatography/electrospray ionization-triple quadrupole mass spectrometry-was adopted for the detection and identification of polar halogenated DBPs in these water samples. With this approach, 11 new putative aromatic halogenated DBPs were identified, and they were classified into four groups: dihalo-4-hydroxybenzaldehydes, dihalo-4-hydroxybenzoic acids, dihalo-salicylic acids, and trihalo-phenols. A mechanism for the formation of the four groups of new aromatic halogenated DBPs was proposed. It was found that increasing the bromide concentration shifted the entire polar halogenated DBPs as well as the four groups of new DBPs from being less brominated to being more brominated; these new aromatic halogenated DBPs might be important intermediate DBPs formed in drinking water chlorination. Moreover, the speciation of the four groups of new DBPs was modeled: the speciation patterns of the four groups of new DBPs well matched those determined from the model equations, and the reactivity differences between HOBr and HOCl in reactions forming the four groups of new DBPs were larger than those in reactions forming trihalomethanes and haloacetic acids.

  17. 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.

  18. Formation of bromate and halogenated disinfection byproducts during chlorination of bromide-containing waters in the presence of dissolved organic matter and CuO

    KAUST Repository

    Liu, Chao; Croue, Jean-Philippe

    2015-01-01

    Previous studies showed that significant bromate (BrO3-) can be formed via the CuO-catalyzed disproportionation of hypobromous acid (HOBr) pathway. In this study, the influence of CuO on the formation of BrO3- and halogenated disinfection byproducts (DBPs) (e.g., trihalomethanes, THMs and haloacetic acids, HAAs) during chlorination of six dissolved organic matter (DOM) isolates was investigated. Only in the presence of slow reacting DOM (from treated Colorado River water, i.e., CRW-BF-HPO), significant BrO3- formation is observed, which competes with bromination of DOM (i.e., THM and HAA formation). Reactions between HOBr and 12 model compounds in the presence of CuO indicates that CuO-catalyzed HOBr disproportionation is completely inhibited by fast reacting phenols, while it predominates in the presence of practically unreactive compounds (acetone, butanol, propionic, and butyric acids). In the presence of slow reacting di- and tri-carboxylic acids (oxalic, malonic, succinic, and citric acids), BrO3- formation varies, depending on its competition with bromoform and dibromoacetic acid formation (i.e., bromination pathway). The latter pathway can be enhanced by CuO due to the activation of HOBr. Therefore, increasing CuO dose (0-0.2 g L-1) in a reaction system containing chlorine, bromide, and CRW-BF-HPO enhances the formation of BrO3-, total THMs and HAAs. Factors including pH and initial reactant concentrations influence the DBP formation. These novel findings have implications for elevated DBP formation during transportation of chlorinated waters in copper-containing distribution systems.

  19. Formation of bromate and halogenated disinfection byproducts during chlorination of bromide-containing waters in the presence of dissolved organic matter and CuO

    KAUST Repository

    Liu, Chao

    2015-12-02

    Previous studies showed that significant bromate (BrO3-) can be formed via the CuO-catalyzed disproportionation of hypobromous acid (HOBr) pathway. In this study, the influence of CuO on the formation of BrO3- and halogenated disinfection byproducts (DBPs) (e.g., trihalomethanes, THMs and haloacetic acids, HAAs) during chlorination of six dissolved organic matter (DOM) isolates was investigated. Only in the presence of slow reacting DOM (from treated Colorado River water, i.e., CRW-BF-HPO), significant BrO3- formation is observed, which competes with bromination of DOM (i.e., THM and HAA formation). Reactions between HOBr and 12 model compounds in the presence of CuO indicates that CuO-catalyzed HOBr disproportionation is completely inhibited by fast reacting phenols, while it predominates in the presence of practically unreactive compounds (acetone, butanol, propionic, and butyric acids). In the presence of slow reacting di- and tri-carboxylic acids (oxalic, malonic, succinic, and citric acids), BrO3- formation varies, depending on its competition with bromoform and dibromoacetic acid formation (i.e., bromination pathway). The latter pathway can be enhanced by CuO due to the activation of HOBr. Therefore, increasing CuO dose (0-0.2 g L-1) in a reaction system containing chlorine, bromide, and CRW-BF-HPO enhances the formation of BrO3-, total THMs and HAAs. Factors including pH and initial reactant concentrations influence the DBP formation. These novel findings have implications for elevated DBP formation during transportation of chlorinated waters in copper-containing distribution systems.

  20. Volatile Short-chain Chlorinated Hydrocarbons in the Groundwater of the City of Zagreb

    OpenAIRE

    Marijanović-Rajčić, M.; Senta, A.

    2008-01-01

    The aim of the study was to assess the quality of the groundwater sampled from private wells and the public water-supply system in terms of estimating the contamination caused by short-chain chlorinated hydrocarbons, as well as to estimate the exposure of the citizens dwelling in different suburbs to these pollutants of their drinking water (Fig. 1). The aim of the study was also to determine which suburb is supplied through the public water-supply system with water originating from the Sašna...

  1. Ozonization effects on trihalo methane formation during the disinfection of drinking water with chlorine; Efectos de la ozonizacion sobre la formacion de trihalometanos durante la desinfeccion final del agua potable con cloro

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez Vidal, F. J.; Perez Serrano, A.; Orozco Barrentxea, C.; Sanllorente Santamaria, M. C.; Ibeas Reoyo, M. V.

    2001-07-01

    One of the main aspects in the control of drinking water treatment is the formation of disinfection by-products (DBP), some of the most important are the trihalomethanes (THM). The use of ozone as primary disinfectant in drinking water treatment plants reduces noticeably the amount of THM generated after the chlorination at the end of the treatment. The aim of this work is to study the main factors influencing the ozone effect in this process: the delay between the time of ozonization and chlorination, the applied ozone dose and the presence of bromide ion ind the raw water. These factors have been studied on natural waters (Uzquiza Reservoir-Burgos) and on synthetic waters (fulvic and humic acids extracted from the mentioned reservoir). (Author) 36 refs.

  2. The study of chloroform levels during water disinfection by chlorination reference to health risk in drinking water of karachi (pakistan)

    International Nuclear Information System (INIS)

    Khawaja, H.A.; Khattak, I.

    2008-01-01

    This study presents the levels of the chloroform formation during water disinfiction treatment by chlorination with the subsequent formation of by-products like trihalomethanes (THMs) are formed. These THMs in drinking water are found in the form of chloroform, bromodichloromethane, Chlorodibromomethane and bromoform. Out of these four compounds chloroform is the major culprit and Contribute 9.0% of the total THMs concentration (I). Therefore the present work was focused on the Estimation of levels of chloroform in the drinking water samples of Karachi city (Pakistan) by using Bootstrapping statistical technique with regards to the average cancer risk in the community. (author)

  3. Interim report on testing of off-gas treatment technologies for abatement of atmospheric emissions of chlorinated volatile organic compounds

    International Nuclear Information System (INIS)

    Haselow, J.S.; Jarosch, T.R.; Rossabi, J.; Burdick, S.; Lombard, K.

    1993-12-01

    The purpose of this report is to briefly summarize the results to date of the off-gas treatment program for atmospheric emissions of chlorinated volatile organic compounds (CVOCs), in particular trichloroethylene (TCE) and perchloroethylene (PCE). This program is part of the Department of Energy's Office of Technology Development's Integrated Demonstration for Treatment of Organics in Soil and Water at a Non-Arid Site. The off-gas treatment program was initiated after testing of in-situ air stripping with horizontal wells was completed. That successful test expectedly produced atmospheric emissions of CVOCs that were unabated. It was decided after that test that an off-gas treatment program would complement the Integrated Demonstration not only because off-gas treatment is an integral portion of remediation of CVOC contamination in groundwater and soil but also because several technologies were being developed across the US to mitigate CVOC emissions. A single platform for testing off-gas treatment technologies would facilitate systematic and unbiased evaluation of the emerging technologies

  4. Final Report on Testing of Off-Gas Treatment Technologies for Abatement of Atmospheric Emissions of Chlorinated Volatile Organic Compounds

    International Nuclear Information System (INIS)

    Jarosch, T.R.; Haselow, J.S.; Rossabi, J.; Burdick, S.A.; Raymond, R.; Young, J.E.; Lombard, K.H.

    1995-01-01

    The purpose of this report is to summarize the results of the program for off-gas treatment of atmospheric emissions of chlorinated volatile organic compounds (CVOCs), in particular trichloroethylene (TCE) and perchloroethylene (PCE). This program was funded through the Department of Energy Office of Technology Development's VOC's in Non-Arid Soils Integrated Demonstration (VNID). The off-gas treatment program was initiated after testing of in-situ air stripping with horizontal wells was completed (Looney et al., 1991). That successful test expectedly produced atmospheric emissions of CVOCs that were unabated. It was decided after that test that an off-gas treatment is an integral portion of remediation of CVOC contamination in groundwater and soil but also because several technologies were being developed across the United States to mitigate CVOC emissions. A single platform for testing off-gas treatment technologies would facilitate cost effective evaluation of the emerging technologies. Another motivation for the program is that many CVOCs will be regulated under the Clean Air Act Amendments of 1990 and are already regulated by many state regulatory programs. Additionally, compounds such as TCE and PCE are pervasive subsurface environmental contaminants, and, as a result, a small improvement in terms of abatement efficiency or cost will significantly reduce CVOC discharges to the environment as well as costs to United States government and industry

  5. Effects of Chlorine on Enterovirus RNA Degradation

    Science.gov (United States)

    The primary mechanism of disinfection of waterborne pathogens by chlorine has always been believed to be due to the alteration of proteins by free chlorine and subsequent disruption of their biological structure.

  6. Comparison of atmosphere/aquatic environment concentration ratio of volatile chlorinated hydrocarbons between temperate regions and Antarctica.

    Science.gov (United States)

    Zoccolillo, Lelio; Amendola, Luca; Insogna, Susanna

    2009-09-01

    For the purpose of understanding the transport and deposition mechanisms and the air-water distribution of some volatile chlorinated hydrocarbons (VCHCs), their atmosphere/aquatic environment concentration ratio was evaluated. In addition, for the purpose of differentiating VCHC behaviour in a temperate climate from its behaviour in a polar climate, the atmosphere/aquatic environment concentration ratio evaluated in matrices from temperate zones was compared with the concentration ratio evaluated in Antarctic matrices. In order to perform air samplings also at rigid Antarctic temperatures, the sampling apparatus, consisting of a diaphragm pump and canisters, was suitably modified. Chloroform, 1,1,1-trichloroethane, tetrachloromethane, 1,1,2-trichloroethylene and tetrachloroethylene were measured in air, water and snow using specific techniques composed of a purpose-made cryofocusing-trap-injector (for air samples) and a modified purge-and-trap injector (for aqueous samples) coupled to a gas chromatograph with mass spectrometric detection operating in selected ion monitoring mode. The VCHCs were retrieved in all the investigated matrices, both Italian and Antarctic, with concentrations varying from tens to thousands of ng m(-3) in air and from digits to hundreds of ng kg(-1) in water and snow. The atmosphere/aquatic environment concentration ratios were always found to be lower than 1. In particular, the Italian air/water concentration ratios were smaller than the Antarctic ones, by reason of the higher atmospheric photochemical activity in temperate zones. On the other hand, the Antarctic air/snow concentration ratios proved to be largely in favour of snow with respect to the Italian ratios, thus corroborating the hypothesis of a more efficient VCHC deposition mechanism and accumulation on Antarctic snow.

  7. 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.

  8. 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.

  9. 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...

  10. 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

  11. 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.

  12. Catalytic oxidation of chlorinated volatile organic compounds, dichloromethane and perchloroethylene. New knowledge for the industrial CVOC emission abatement

    Energy Technology Data Exchange (ETDEWEB)

    Pitkaeaho, S.

    2013-09-01

    The releases of chlorinated volatile organic compounds (CVOCs) are controlled by strict regulations setting high demands for the abatement systems. Low temperature catalytic oxidation is a viable technology to economically destroy these often refractory emissions. Catalysts applied in the oxidation of CVOCs should be highly active and selective but also maintain a high resistance towards deactivation. In this study, a total of 33 different {gamma}-Al{sub 2}O{sub 3} containing metallic monoliths were studied in dichloromethane (DCM) and 25 of them in perchloroethylene (PCE) oxidation. The active compounds used were Pt, Pd, Rh or V{sub 2}O{sub 5} alone or as mixtures. The catalysts were divided into three different testing sets: industrial, CVOC and research catalysts. ICP-OES, physisorption, chemisorption, XRD, UV-vis DRS, isotopic oxygen exchange, IC, NH{sub 3}-TPD, H{sub 2}-TPR and FESEM-EDS were used to characterise the catalysts. Screening of the industrial catalysts revealed that the addition of V{sub 2}O{sub 5} improved the performance of the catalyst. DCM abatement was easily affected by the addition of VOC or water, but the effect on the PCE oxidation was only minor. Based on these screening tests, a set of CVOC catalysts were developed and installed into an industrial incinerator. The comparison between the laboratory and industrial scale studies showed that DCM oxidation in an industrial incinerator could be predicted relatively well. Instead, PCE was always seen to be oxidised far better in an industrial unit indicating that the transient oxidation conditions are beneficial for the PCE oxidation. Before starting the experiments with research catalysts, the water feed was optimised to 1.5 wt.%. Besides enhancing the HCl yields, water improved the DCM and PCE conversions. In the absence of oxygen, i.e. during destructive adsorption, the presence of water was seen to have an even more pronounced effect on the HCl formation and on the catalysts

  13. 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 ...

  14. Low-concentration tailing and subsequent quicklime-enhanced remediation of volatile chlorinated hydrocarbon-contaminated soils by mechanical soil aeration.

    Science.gov (United States)

    Ma, Yan; Du, Xiaoming; Shi, Yi; Xu, Zhu; Fang, Jidun; Li, Zheng; Li, Fasheng

    2015-02-01

    Mechanical soil aeration has long been regarded as an effective ex-situ remediation technique and as suitable for remediation of large-scale sites contaminated by volatile organic compounds (VOCs) at low cost. However, it has been reported that the removal efficiency of VOCs from soil is relatively low in the late stages of remediation, in association with tailing. Tailing may extend the remediation time required; moreover, it typically results in the presence of contaminants residues at levels far exceeding regulations. In this context, the present study aimed to discuss the tailing that occurs during the process of remediation of soils contaminated artificially with volatile chlorinated hydrocarbons (VCHs) and to assess possible quicklime-enhanced removal mechanisms. The results revealed the following conclusions. First, temperature and aeration rate can be important controls on both the timing of appearance of tailing and the levels of residual contaminants. Furthermore, the addition of quicklime to soil during tailing can reduce the residual concentrations rapidly to below the remedial target values required for site remediation. Finally, mechanical soil aeration can be enhanced using quicklime, which can improve the volatilization of VCHs via increasing soil temperature, reducing soil moisture, and enhancing soil permeability. Our findings give a basic understanding to the elimination of the tailing in the application of mechanical soil aeration, particularly for VOCs-contaminated soils. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Quicklime-induced changes of soil properties: Implications for enhanced remediation of volatile chlorinated hydrocarbon contaminated soils via mechanical soil aeration.

    Science.gov (United States)

    Ma, Yan; Dong, Binbin; He, Xiaosong; Shi, Yi; Xu, Mingyue; He, Xuwen; Du, Xiaoming; Li, Fasheng

    2017-04-01

    Mechanical soil aeration is used for soil remediation at sites contaminated by volatile organic compounds. However, the effectiveness of the method is limited by low soil temperature, high soil moisture, and high soil viscosity. Combined with mechanical soil aeration, quicklime has a practical application value related to reinforcement remediation and to its action in the remediation of soil contaminated with volatile organic compounds. In this study, the target pollutant was trichloroethylene, which is a volatile chlorinated hydrocarbon pollutant commonly found in contaminated soils. A restoration experiment was carried out, using a set of mechanical soil-aeration simulation tests, by adding quicklime (mass ratios of 3, 10, and 20%) to the contaminated soil. The results clearly indicate that quicklime changed the physical properties of the soil, which affected the environmental behaviour of trichloroethylene in the soil. The addition of CaO increased soil temperature and reduced soil moisture to improve the mass transfer of trichloroethylene. In addition, it improved the macroporous cumulative pore volume and average pore size, which increased soil permeability. As soil pH increased, the clay mineral content in the soils decreased, the cation exchange capacity and the redox potential decreased, and the removal of trichloroethylene from the soil was enhanced to a certain extent. After the addition of quicklime, the functional group COO of soil organic matter could interact with calcium ions, which increased soil polarity and promoted the removal of trichloroethylene. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Treatability of volatile chlorinated hydrocarbon-contaminated soils of different textures along a vertical profile by mechanical soil aeration: A laboratory test.

    Science.gov (United States)

    Ma, Yan; Shi, Yi; Hou, Deyi; Zhang, Xi; Chen, Jiaqi; Wang, Zhifen; Xu, Zhu; Li, Fasheng; Du, Xiaoming

    2017-04-01

    Mechanical soil aeration is a simple, effective, and low-cost soil remediation technology that is suitable for sites contaminated with volatile chlorinated hydrocarbons (VCHs). Conventionally, this technique is used to treat the mixed soil of a site without considering the diversity and treatability of different soils within the site. A laboratory test was conducted to evaluate the effectiveness of mechanical soil aeration for remediating soils of different textures (silty, clayey, and sandy soils) along a vertical profile at an abandoned chloro-alkali chemical site in China. The collected soils were artificially contaminated with chloroform (TCM) and trichloroethylene (TCE). Mechanical soil aeration was effective for remediating VCHs (removal efficiency >98%). The volatilization process was described by an exponential kinetic function. In the early stage of treatment (0-7hr), rapid contaminant volatilization followed a pseudo-first order kinetic model. VCH concentrations decreased to low levels and showed a tailing phenomenon with very slow contaminant release after 8hr. Compared with silty and sandy soils, clayey soil has high organic-matter content, a large specific surface area, a high clay fraction, and a complex pore structure. These characteristics substantially influenced the removal process, making it less efficient, more time consuming, and consequently more expensive. Our findings provide a potential basis for optimizing soil remediation strategy in a cost-effective manner. Copyright © 2016. Published by Elsevier B.V.

  17. Degradation of acrylamide by the UV/chlorine advanced oxidation process.

    Science.gov (United States)

    Gao, Ze-Chen; Lin, Yi-Li; Xu, Bin; Pan, Yang; Xia, Sheng-Ji; Gao, Nai-Yun; Zhang, Tian-Yang; Chen, Ming

    2017-11-01

    The degradation of acrylamide (AA) during UV/chlorine advanced oxidation process (AOP) was investigated in this study. The degradation of AA was negligible during UV irradiation alone. However, AA could be effectively degraded and mineralized during UV/chlorination due to the generation of hydroxyl radicals (OH). The degradation kinetics of AA during UV/chlorination fitted the pseudo-first order kinetics with the rate constant between AA and OH radicals being determined as 2.11 × 10 9  M -1  s -1 . The degradation rate and mineralization of AA during UV/chlorination were significantly promoted at acidic conditions as well as increasing chlorine dosage. The volatile degradation products of AA during UV/chlorination were identified using gas chromatography-mass spectrometry and the degradation pathways were then proposed accordingly. The formation of disinfection by-products (DBPs) in Milli-Q water and tap water during UV/chlorination of AA was also investigated. The DBPs included chloroform, dichloroacetonitrile, trichloroacetonitrile, 2,2-dichloroacetamide and 2,2,2-trichloroacetamide. Furthermore, the variations of AA degradation during UV/chlorination in different real water samples were evaluated. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. 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

  19. Quantitative microbial risk assessment for an indoor swimming pool with chlorination compared to a UV-based treatment

    NARCIS (Netherlands)

    Peters, M.C.F.M.; Keuten, M.G.A.; de Kreuk, M.K.; Vrouwenvelder, J.S.; Rietveld, L.C.; Medema, G.

    2017-01-01

    Aims Most swimming pools use residual disinfectants like chlorine for disinfection. The use of chlorine has several drawbacks: some waterborne-pathogens are chlorine resistant and disinfection by-products (DBPs) may be formed which are associated with various health risks. Therefore, an alternative

  20. 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...

  1. Chlorination and chloramines formation

    International Nuclear Information System (INIS)

    Yee, Lim Fang; Mohd Pauzi Abdullah; Sadia Ata; Abbas Abdullah; Basar IShak; Khairul Nidzham

    2008-01-01

    Chlorination is the most important method of disinfection in Malaysia which aims at ensuring an acceptable and safe drinking water quality. The dosing of chlorine to surface water containing ammonia and nitrogen compounds may form chloramines in the treated water. During this reaction, inorganic and organic chloramines are formed. The recommended maximum acceptable concentration (MAC) for chloramines in drinking water is 3000 μg/L. The production of monochloramine, dichloramine and trichloramine is highly dependent upon pH, contact time and the chlorine to ammonia molar ratio. The purpose of this study is to examine the formation of chloramines that occur upon the chlorination during the treatment process. Chloramines were determined using the N,N-diethyl-p-phenylenediamine (DPD) colorimetric method. The influences of ammonia, pH and chlorine dosage on the chloramines formation were also studied. This paper presents a modeling approach based on regression analysis which is designed to estimate the formation of chloramines. The correlation between the concentration of chloramines and the ammonia, pH and chlorine dosage was examined. In all cases, the quantity of chloramines formed depended linearly upon the amount of chlorine dosage. On the basis of this study it reveals that the concentration of chloramines is a function of chlorine dosage and the ammonia concentration to the chlorination process. PH seems to not significantly affect the formation of chloramines. (author)

  2. Desinfecção de efluentes sanitários através de dióxido de cloro Disinfection of domestic wastewater using chlorine dioxide

    Directory of Open Access Journals (Sweden)

    Flávio Rubens Lapolli

    2005-09-01

    Full Text Available A desinfecção dos esgotos deve ser considerada quando se pretende reduzir os riscos de transmissão de doenças infecto-contagiosas. Nesse sentido, os requisitos de qualidade de uma água devem ser avaliados em função dos usos previstos para a mesma. O dióxido de cloro (ClO2 possui excelentes propriedades bactericidas, virucidas, esporocidas e algicidas e, devido a isso, é usado como desinfetante de água de abastecimento e efluente doméstico, bem como inibidor de crescimento de algas. O objetivo do trabalho foi estudar a melhor dosagem para uma boa desinfecção de efluentes sanitários previamente tratados mediante lodos ativados por aeração prolongada, avaliar a inativação de coliformes e o residual de dióxido de cloro remanescente. Foram realizados ensaios para diferentes dosagens de dióxido de cloro e diferentes tempos de contato. Os resultados obtidos mostraram que a dosagem mais indicada para desinfecção do efluente estudado foi 2,0 mg ClO2/L com um tempo de contato de 20 minutos, condições sob as quais é atingido 100% de remoção de coliformes fecais e oxidada parcialmente a matéria orgânica remanescente, em tanto que os valores de pH e residual de ClO2 do efluente mantêm-se dentro dos admitidos pelas normativas brasileira e estadunidense em vigor. O estudo econômico levado a cabo permitiu concluir que a desinfecção de efluente doméstico mediante dióxido de cloro pode ser economicamente viável.Disinfection of sewage must be considered when reduction of infect-contagious disease transmission risks is intended. Thus, water quality requirements have to be evaluated in function of its predetermined uses. Chlorine dioxide (ClO2 has excellent bactericide, viruscide, sporicide and algaecide properties and, by these reasons, it is used as a disinfectant for drinking water and municipal sewage and as an algal growing inhibitor. The objective of this work was to investigate the most adequate ClO2 doses for an adequate

  3. Volatility

    Directory of Open Access Journals (Sweden)

    María Sánchez

    2016-11-01

    Full Text Available The action consists of moving with small kicks a tin of cola refresh -without Brand-from a point of the city up to other one. During the path I avoid bollards, the slope differences between sidewalks, pedestrians, parked motorcycles, etc. Volatility wants to say exactly that the money is getting lost. That the money is losing by gentlemen and by ladies who are neither financial sharks, nor big businessmen… or similarly, but ingenuous people, as you or as me, who walk down the street.

  4. 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 )...

  5. 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

  6. 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

  7. 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...

  8. 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 ...

  9. 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.

  10. Site profiles of low-volatile chlorinated hydrocarbons - cause-oriented monitoring in aquatic media. Vol.2. Low-volatile chlorinated hydrocarbons in surface water, sediments, suspended matter and fish of the Elbe river and its tributaries; Standortprofile schwerfluechtiger chlorierter Kohlenwasserstoffe (SCKW) - ursachenorientiertes Monitoring in aquatischen Medien. Bd. 2. SCKW in Oberflaechenwasser, Sediment, Schwebstoffen und Fischen aus der Elbe und Nebenfluessen

    Energy Technology Data Exchange (ETDEWEB)

    Heinisch, E.; Kettrup, A.; Gebefuegi, I.; Martens, D.; Bergheim, W.; Wenzel, S.

    2001-07-01

    Evaluating the primary data from ARGE ELBE, LAU Halle/Saale and the Environmental Specimen Banking (Umweltprobenbank) as well from publications from the Czech Republic (CHMU) the concentrations of the following low volatile chlorinated hydrocarbons were established for surface water, sediment, breams and eels from the rivers Elbe, Schwarze Elster, Mulde and Saale partly from 1989 till 1999: DDT and its metabolites DDE and DDD, partly as 2,4'- and 4,4' isomers; HCH ({alpha}-, {beta}-, {gamma}- and {delta} isomers); chlorinated benzenes with 1-6 Cl atoms and octachlorostyrene. The data evaluated were drawn up into tables - comprehensive in a separate supplement, in short versions within the text - and consolidated into graphs. Aim of the paper was a cause-oriented monitoring. The by far most important emission sources, found from the distance and time profiles as well as from special assessments of the substance patterns, were chemical plants. (orig.) [German] Durch Auswertung von Primaerdaten der ARGE ELBE, des LAU Halle/Saale und der Umweltprobenbank sowie von Publikationen aus Tschechien (CHMU) wurden fuer Oberflaechenwasser, Sediment, Brassen/Bleien und Aale aus der Elbe, Schwarzen Elster, Mulde und Saale fuer die Jahre von z.T. 1989 bis 1999 die Konzentrationen der folgenden schwerfluechtigen Kohlenwasserstoffe (SCKW) ermittelt: DDT und seine Metabolite DDE und DDD, z.T. als 2,4'- und 4,4'-Isomere; HCH ({alpha}-, {beta}-, {gamma}- und {delta}-Isomere); chlorierte Benzole mit 1-6 Cl-Atomen und Octachlorstyrol. Die ausgewerteten Daten wurden zu Tabellen - ausfuehrlich in einem gesonderten Tabellenanhang und verkuerzt im Textteil - zusammengestellt sowie zu Grafiken verdichtet. Ziel der Arbeit war ein ursachenorientiertes Monitoring. Als mit Abstand wesentlichste Emissionsquellen konnten anhand von Streckenprofilen und Zeitrastern sowie durch spezielle Auswertungen der Stoffmusterverteilungen Chemibetriebe ermittelt werden. (orig.)

  11. Detection of chlorinated and brominated byproducts of drinking water disinfection using electrospray ionization-high-field asymmetric waveform ion mobility spectrometry-mass spectrometry.

    Science.gov (United States)

    Ells, B; Barnett, D A; Froese, K; Purves, R W; Hrudey, S; Guevremont, R

    1999-10-15

    The lower limit of detection for low molecular weight polar and ionic analytes using electrospray ionization-mass spectrometry (ESI-MS) is often severely compromised by an intense background that obscures ions of trace components in solution. Recently, a new technique, referred to as high-field asymmetric waveform ion mobility spectrometry (FAIMS), has been shown to separate gas-phase ions at atmospheric pressure and room temperature. A FAIMS instrument is an ion filter that may be tuned, by control of electrical voltages, to continuously transmit selected ions from a complex mixture. This capability offers significant advantages when FAIMS is coupled with ESI, a source that generates a wide variety of ions, including solvent clusters and salt adducts. In this report, the tandem arrangement of ESI-FAIMS-MS is used for the analysis of haloacetic acids, a class of disinfection byproducts regulated by the US EPA. FAIMS is shown to effectively discriminate against background ions resulting from the electrospray of tap water solutions containing the haloacetic acids. Consequently, mass spectra are simplified, the selectivity of the method is improved, and the limits of detection are lowered compared with conventional ESI-MS. The detection limits of ESI-FAIMS-MS for six haloacetic acids ranged between 0.5 and 4 ng/mL in 9:1 methanol/tap water (5 and 40 ng/mL in the original tap water samples) with no preconcentration, derivatization, or chromatographic separation prior to analysis.

  12. O uso de cloro na desinfecção de águas, a formação de trihalometanos e os riscos potenciais à saúde pública Chlorine use in water disinfection, trihalomethane formation, and potential risks to public health

    Directory of Open Access Journals (Sweden)

    Sheila T. Meyer

    1994-03-01

    Full Text Available Antes do desenvolvimento da teoria dos microorganismos como causadores de doenças (1880, acreditava-se que estas eram transmitidas através de odores. A desinfecção, tanto da água de abastecimento como dos esgotos, surgiu como uma tentativa da eliminação desses odores. Existem muitos agentes desinfetantes, mas, em geral, o cloro é o principal produto utilizado na desinfecção de águas de abastecimento. A presença de compostos orgânicos em águas que sofrem o processo de cloração resulta na formação dos trihalometanos, compostos formados por um átomo de carbono, um de hidrogênio e três de halogênio (cloro, bromo, iôdo. Os trihalometanos são considerados compostos carcinogênicos e sua presença na água deve ser evitada. Levantamentos epidemiológicos relacionando a concentração dos trihalometanos com a morbidade e a mortalidade por câncer evidenciaram associações positivas em alguns casos de carcinomas. Entretanto, a substituição do cloro por outro desinfetante no tratamento da água pode trazer mais riscos do que benefícios, considerando-se que a diminuição da incidência de doenças transmissíveis pela água somente foi alcançada com a difusão do emprego da técnica de cloração.Before the development of the germ theory relating microorganisms with disease transmission (1880 people believed that diseases were transmitted by odours. Water and sewage disinfection emerged as a method for elimination of odours. There are many disinfecting agents, but chlorine is the main product used to disinfect water. Organic compounds present in water that is chlorinated can result in the formation of trihalomethanes. The latter are basically one atom of carbon, one of hydrogen, and three of a halogen (chlorine, bromine, or iodine. These are considered carcinogenic compounds and their presence in drinking water should therefore be avoided. Epidemiological research has shown an association between trihalomethane concentration

  13. Relation between chlorine with the quality of crude water

    International Nuclear Information System (INIS)

    Lim, Fang Yee; Mohd Pauzi Abdullah

    2008-01-01

    Chlorine as disinfection agent in drinking water was used widely since it was successfully been practiced in drinking water in Jersey City, 1908. Mostly, water treatment plants in Malaysia were using chlorine as disinfection agent to kill pathogen and contaminated materials that can be dangerous to consumer. Because of chlorine was a strongly disinfection agent, it also can react with another chemical components such as manganese, hydrogen, sulfides, ammonia and phenol in water. These reactions happen very fast, and chlorine will not react as disinfection agent unless all the organic and inorganic substitution presented in water reacts with chlorine. These reactions between components will increase demand of chlorine in water. The demand of chlorine in water must be filled before the free radical chlorine occurred. These free radical chlorine will decay into hypochlorous acid and hypochlorite ion that so important in disinfection process to kill pathogens and pollutants in water. Most of water treatment plant to maintain free chlorine up to 0.2 mg/ L in distribution system to consumer. These researches involved determination of parameters that can be trusted to react with the chlorine in nine sampling station along Semenyih River and four stations in water treatment plants. These parameters were determined from ammonia, cyanides, sulfides, phenol, phosphorus, nitrite, manganese, iron and sum of organic carbons. Overall, these researches concluded that ammonia and sum of organic carbons were the most compounds that react with the chlorine to produce tryhalometane and chloramines. Besides that, the concentration of cyanides compounds, sulfide, phenol, phosphorus, nitrite, manganese and iron also decrease after the chlorination process. Results can used to evaluate demanding levels of chlorine in Semenyih River. (author)

  14. Natural attenuation of chlorinated volatile organic compounds in ground water at Operable Unit 1, Naval Undersea Warfare Center, Division Keyport, Washington

    Science.gov (United States)

    Dinicola, Richard S.; Cox, S.E.; Landmeyer, J.E.; Bradley, P.M.

    2002-01-01

    The U.S. Geological Survey (USGS) evaluated the natural attenuation of chlorinated volatile organic compounds (CVOCs) in ground water beneath the former landfill at Operable Unit 1 (OU 1), Naval Undersea Warfare Center, Division Keyport, Washington. The predominant contaminants in ground water are trichloroethene (TCE) and its degradation byproducts cis-1,2-dichloroethene (cisDCE) and vinyl chloride (VC). The Navy planted two hybrid poplar plantations on the landfill in spring of 1999 to remove and control the migration of CVOCs in shallow ground water. Previous studies provided evidence that microbial degradation processes also reduce CVOC concentrations in ground water at OU 1, so monitored natural attenuation is a potential alternative remedy if phytoremediation is ineffective. This report describes the current (2000) understanding of natural attenuation of CVOCs in ground water at OU 1 and the impacts that phytoremediation activities to date have had on attenuation processes. The evaluation is based on ground-water and surface-water chemistry data and hydrogeologic data collected at the site by the USGS and Navy contractors between 1991 and 2000. Previously unpublished data collected by the USGS during 1996-2000 are presented. Natural attenuation of CVOCs in shallow ground water at OU 1 is substantial. For 1999-2000 conditions, approximately 70 percent of the mass of dissolved chlorinated ethenes that was available to migrate from the landfill was completely degraded in shallow ground water before it could migrate to the intermediate aquifer or discharge to surface water. Attenuation of CVOC concentrations appears also to be substantial in the intermediate aquifer, but biodegradation appears to be less significant; those conclusions are less certain because of the paucity of data downgradient of the landfill beneath the tide flats. Attenuation of CVOC concentrations is also substantial in surface water as it flows through the adjacent marsh and out to the tide

  15. Formation of emerging DBPs from the chlorination and chloramination of seawater algal organic matter and related model compounds

    KAUST Repository

    Nihemaiti, Maolida

    2014-01-01

    Limited studies focused on reactions occurring during disinfection and oxidation processes of seawater. The aim of this work was to investigate disinfection by-products (DBPs) formation from the chlorination and chloramination of seawater algal

  16. 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.

  17. 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...

  18. High-Rate Disinfection Techniques for Combined Sewer Overflow (Proceedings Paper)

    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 ), a...

  19. Life Cycle Environmental Impacts of Disinfection Technologies Used in Small Drinking Water Systems.

    Science.gov (United States)

    Jones, Christopher H; Shilling, Elizabeth G; Linden, Karl G; Cook, Sherri M

    2018-03-06

    Small drinking water systems serve a fifth of the U.S. population and rely heavily on disinfection. While chlorine disinfection is common, there is interest in minimizing chemical addition, especially due to carcinogenic disinfection byproducts and chlorine-resistant pathogens, by using ultraviolet technologies; however, the relative, broader environmental impacts of these technologies are not well established, especially in the context of small (environmental trade-offs between chlorine and ultraviolet disinfection via comparative life cycle assessment. The functional unit was the production of 1 m 3 of drinking water to U.S. Treatment included cartridge filtration followed by either chlorine disinfection or ultraviolet disinfection with chlorine residual addition. Environmental performance was evaluated for various chlorine contact zone materials (plastic, concrete, steel), ultraviolet validation factors (1.2 to 4.4), and electricity sources (renewable; U.S. average, high, and low impact grids). Performance was also evaluated when filtration and chlorine residual were not required. From a life cycle assessment perspective, replacing chlorine with UV was preferred only in a limited number of cases (i.e., high pumping pressure but filtration is not required). In all others, chlorine was environmentally preferred, although some contact zone materials and energy sources had an impact on the comparison. Utilities can use these data to inform their disinfection technology selection and operation to minimize environmental and human health impacts.

  20. Disinfection Methods for Swimming Pool Water: Byproduct Formation and Control

    Directory of Open Access Journals (Sweden)

    Huma Ilyas

    2018-06-01

    Full Text Available This paper presents a comprehensive and critical comparison of 10 disinfection methods of swimming pool water: chlorination, electrochemically generated mixed oxidants (EGMO, ultraviolet (UV irradiation, UV/chlorine, UV/hydrogen peroxide (H2O2, UV/H2O2/chlorine, ozone (O3/chlorine, O3/H2O2/chlorine, O3/UV and O3/UV/chlorine for the formation, control and elimination of potentially toxic disinfection byproducts (DBPs: trihalomethanes (THMs, haloacetic acids (HAAs, haloacetonitriles (HANs, trihaloacetaldehydes (THAs and chloramines (CAMs. The statistical comparison is carried out using data on 32 swimming pools accumulated from the reviewed studies. The results indicate that O3/UV and O3/UV/chlorine are the most promising methods, as the concentration of the studied DBPs (THMs and HANs with these methods was reduced considerably compared with chlorination, EGMO, UV irradiation, UV/chlorine and O3/chlorine. However, the concentration of the studied DBPs including HAAs and CAMs remained much higher with O3/chlorine compared with the limits set by the WHO for drinking water quality. Moreover, the enhancement in the formation of THMs, HANs and CH with UV/chlorine compared with UV irradiation and the increase in the level of HANs with O3/UV/chlorine compared with O3/UV indicate the complexity of the combined processes, which should be optimized to control the toxicity and improve the quality of swimming pool water.

  1. The Dutch secret : How to provide safe drinking water without chlorine in the Netherlands

    NARCIS (Netherlands)

    Smeets, P.W.M.H.; Medema, G.J.; Van Dijk, J.C.

    2009-01-01

    The Netherlands is one of the few countries where chlorine is not used at all, neither for primary disinfection nor to maintain a residual disinfectant in the distribution network. The Dutch approach that allows production and distribution of drinking water without the use of chlorine while not

  2. POPULATION DIVERSITY IN MODEL DRINKING WATER BIOFILMS RECEIVING CHLORINE OR MONOCHLORAMINE RESIDUAL

    Science.gov (United States)

    Most water utilities add monochloramine or chlorine as a residual disinfectant in potable water distribution systems (WDS) to control bacterial regrowth. While monochloramine is considered more stable than chlorine, little is known about the fate of this disinfectant or the effec...

  3. CHLORINE INACTIVATION OF CATEGORY "A" BIO-TERRORISM AGENTS

    Science.gov (United States)

    This poster presents information on the inactivation of select bioterrorist agents. Information will be presented on chlorine disinfection of vegetative cells of Brucella suis, Brucella melitensis, Burkholderia mallei, Burkholderia pseudomallei, Francisella tularensis and endos...

  4. Determination of chlorine in nuclear-grade uranium compounds

    International Nuclear Information System (INIS)

    Yang Chunqing; Liu Fuyun; Huang Dianfan

    1988-01-01

    The determination of chlorine in nuclear-grade uranium compounds is discribed. Chlorine is separated from uranium oxide pyrohydrolytically with stream of wet oxygen in a furnace at 800 ∼ 900 deg C. Chlorine is volatilized as hydrochloric acid, absorbed in a dilute alkaline solution and measured with chlorine-selective electrode. This method covers the concentration range of 10 ∼ 500 pm chlorine in uranium oxide. Precision of at least ± 10% and recovery of 85 ∼ 108% have been reported

  5. High-resolution delineation of chlorinated volatile organic compounds in a dipping, fractured mudstone: depth- and strata-dependent spatial variability from rock-core sampling

    Science.gov (United States)

    Goode, Daniel J.; Imbrigiotta, Thomas E.; Lacombe, Pierre J.

    2014-01-01

    Synthesis of rock-core sampling and chlorinated volatile organic compound (CVOC) analysis at five coreholes, with hydraulic and water-quality monitoring and a detailed hydrogeologic framework, was used to characterize the fine-scale distribution of CVOCs in dipping, fractured mudstones of the Lockatong Formation of Triassic age, of the Newark Basin in West Trenton, New Jersey. From these results, a refined conceptual model for more than 55 years of migration of CVOCs and depth- and strata-dependent rock-matrix contamination was developed. Industrial use of trichloroethene (TCE) at the former Naval Air Warfare Center (NAWC) from 1953 to 1995 resulted in dense non-aqueous phase liquid (DNAPL) TCE and dissolved TCE and related breakdown products, including other CVOCs, in underlying mudstones. Shallow highly weathered and fractured strata overlie unweathered, gently dipping, fractured strata that become progressively less fractured with depth. The unweathered lithology includes black highly fractured (fissile) carbon-rich strata, gray mildly fractured thinly layered (laminated) strata, and light-gray weakly fractured massive strata. CVOC concentrations in water samples pumped from the shallow weathered and highly fractured strata remain elevated near residual DNAPL TCE, but dilution by uncontaminated recharge, and other natural and engineered attenuation processes, have substantially reduced concentrations along flow paths removed from sources and residual DNAPL. CVOCs also were detected in most rock-core samples in source areas in shallow wells. In many locations, lower aqueous concentrations, compared to rock core concentrations, suggest that CVOCs are presently back-diffusing from the rock matrix. Below the weathered and highly fractured strata, and to depths of at least 50 meters (m), groundwater flow and contaminant transport is primarily in bedding-plane-oriented fractures in thin fissile high-carbon strata, and in fractured, laminated strata of the gently

  6. Water Chlorination for human consumption

    International Nuclear Information System (INIS)

    Innocenti, A.; Giacosa, D.; Segatori, M.

    1999-01-01

    Beginning from this issue, an initiative of Federgasacqua (Federal association dealing with the gas and the water) takes place through the activities of the Task Forces Water Quality Control and Materials and Processes, which aim is to offer to the water industry operators and updated information concerning some main subjects, emphasizing in particular the technical and management applied topics. The paper deals with the chlorination processes in drinking water treatment. An overview of the italian situation is presented, concerning disinfection as well as other oxidation processes, together with an historical background on chlorination. Concerning the applications, the chemical technologies and the main processes, the disinfectant effectiveness and the byproducts formation have been described. Further, the regulations in force have been reported and discussed on national and international bases [it

  7. 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)

  8. 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...

  9. 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.

  10. 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

  11. 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

  12. 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...

  13. Inactivation of Aspergillus flavus in drinking water after treatment with UV irradiation followed by chlorination

    International Nuclear Information System (INIS)

    Al-Gabr, Hamid Mohammad; Zheng, Tianling; Yu, Xin

    2013-01-01

    The disinfection process for inactivating microorganisms at drinking water treatment plants is aimed for safety of drinking water for humans from a microorganism, such as bacteria, viruses, algae, fungi by using chlorination, ozonation, UV irradiation, etc. In the present study, a combination of two disinfectants, UV irradiation followed by chlorination, was evaluated for inactivating Aspergillus flavus under low contact time and low dosage of UV irradiation. The results indicated an inverse correlation between the inactivation of A. flavus by using UV irradiation only or chlorination alone. By using UV radiation, the 2 log 10 control of A. flavus was achieved after 30 s of irradiation, while chlorination was observed to be more effective than UV, where the 2 log was achieved at chlorine concentration of 0.5, 1, 2 and 3 mg/l, in contact time of 60, 5, 1 and 1 min, respectively. However, combined use (UV irradiation followed by chlorination) was more effective than using either UV or chlorination alone; 5 s UV irradiation followed by chlorination produced 4 log 10 reduction of A. flavus at chlorine concentrations of 2 and 3 mg/l under a contact time of 15 min. The results indicated that efficiency of UV irradiation improves when followed by chlorination at low concentrations. - Highlights: • As a disinfectant, chlorine is more effective than UV in inactivating Aspergillus flavus. • As a combined method, UV irradiation followed by chlorination shows high efficiency. • UV irradiation can improve effectiveness of chlorination in reducing Aspergillus flavus

  14. Monte-Carlo and multi-exposure assessment for the derivation of criteria for disinfection byproducts and volatile organic compounds in drinking water: Allocation factors and liter-equivalents per day.

    Science.gov (United States)

    Akiyama, Megumi; Matsui, Yoshihiko; Kido, Junki; Matsushita, Taku; Shirasaki, Nobutaka

    2018-06-01

    The probability distributions of total potential doses of disinfection byproducts and volatile organic compounds via ingestion, inhalation, and dermal exposure were estimated with Monte Carlo simulations, after conducting physiologically based pharmacokinetic model simulations to takes into account the differences in availability between the three exposures. If the criterion that the 95th percentile estimate equals the TDI (tolerable daily intake) is regarded as protecting the majority of a population, the drinking water criteria would be 140 (trichloromethane), 66 (bromodichloromethane), 157 (dibromochloromethane), 203 (tribromomethane), 140 (dichloroacetic acid), 78 (trichloroacetic acid), 6.55 (trichloroethylene, TCE), and 22 μg/L (perchloroethylene). The TCE criterion was lower than the Japanese Drinking Water Quality Standard (10 μg/L). The latter would allow the intake of 20% of the population to exceed the TDI. Indirect inhalation via evaporation from water, especially in bathrooms, was the major route of exposure to compounds other than haloacetic acids (HAAs) and accounted for 1.2-9 liter-equivalents/day for the median-exposure subpopulation. The ingestion of food was a major indirect route of exposure to HAAs. Contributions of direct water intake were not very different for trihalomethanes (30-45% of TDIs) and HAAs (45-52% of TDIs). Copyright © 2018 Elsevier Inc. All rights reserved.

  15. 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.

  16. Chlorine poisoning

    Science.gov (United States)

    ... gas) Gas released when opening a partially filled industrial container of chlorine tablets that have been sitting ... change in acid level of the blood (pH balance), which leads to damage in all of the ...

  17. Utilisation of chlorine-dioxide and peracetic acid as disinfectants of effluents from Bologna waste water treatment plant; Sperimentazione di tecniche di disinfezione mediante biossido di cloro e acido peracetico applicate alle acque reflue dell'impianto di trattamento della citta' di Bologna

    Energy Technology Data Exchange (ETDEWEB)

    Mancini, M.L. [Bologna Univ., Bologna (Italy). Dipt. di Ingegneria delle Strutture, dei Trasporti, delle Acque, del Rilevamento e del Territorio; Sorrentino, M.

    2000-01-01

    The necessity to optimize the disinfection phase in the treatment plant of waste water of Bologna made possible an experimental survey about the efficacy of two disinfectant agents utilized: chlorine-dioxide and peracetic acid. Object of the survey is to verify the possibility of utilize, full scale, also peracetic acid as disinfection agent. The experimentation regarded the reals flows adduced and discharged from the plant and it may be an useful reference to verify performance of post-treatment constructed wetlands. Particularly it has been possible to assay the efficacy of the different treatment in waste water with residual concentrations of suspended solids. [Italian] La necessita' di ottimizzare la fase di disinfezione nell'impianto di trattamento acque reflue della citta' di Bologna, sia per il miglioramento delle rese di inattivazione, sia per la riduzione dei costi di esercizio, ha reso necessaria un'indagine sperimentale sull'efficacia di due agenti disinfettanti utilizzati: il biossido di cloro e l'acido peracetico. Scopo dell'indagine e' quello di verificare la possibilita' di impiegare, a scala reale, per il refluo tipico dell'impianto di Bologna, anche l'acido peracetico quale agente di disinfezione. La sperimentazione, condotta ha interessato le portate reali addotte e scaricate dall'impianto e puo' costituire un riferimento utile verificare la fattibilita' igienico-sanitaria di post-trattamenti di lagunaggio o fertirrigazione. In particolare si e' potuta saggiare l'efficacia dei diversi sistemi di trattamento sui reflui aventi concentrazioni residue non trascurabili di solidi sospesi.

  18. Chlorination of cooling water: a source of chlorine-containing organic compounds with possible environmental significance

    International Nuclear Information System (INIS)

    Jolley, R.L.; Gehrs, C.W.; Pitt, W.W. Jr.

    1976-01-01

    Chlorination of cooling waters may be a source of environmentally significant pollutants. Many water-soluble chlorine-containing organic compounds of low volatility were found in a sample of cooling water chlorinated to a 2-mg/l chlorine concentration in the laboratory. The compounds were separated and detected using a coupled 36 Cl-tracer--high-resolution liquid chromatographic technique developed at the Oak Ridge National Laboratory for determination of chlorinated organics in process effluents. For a chlorination contact time of 75 min at 25 0 C, the yield of chlorine in the form of chloro-organics amounted to 0.78% of the chlorine dosage. It is estimated that the yield is about 0.5% under typical reaction conditions in the electric power plant cooling system chosen for study. Because chlorine is commonly used to remove slime films from the cooling systems of electric power plants, as a means of maintaining high operational efficiency, it is estimated that several hundred tons of chlorinated organics are produced annually in the nation by this antifoulant process. The chromatographic elution positions of some of the separated constituents correspond to those of compounds separated and partially identified from chlorinated sewage treatment plant effluents. The results of this study indicate the formation of chloro-organics during the chlorination of cooling waters should be thoroughly examined, particularly with respect to their identification and determination of possible toxicological properties

  19. 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.

  20. 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.

  1. 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

  2. Trihalomethanes formation in marine environment in front of Nuweibaa desalination plant as a result of effluents loaded by chlorine residual

    Directory of Open Access Journals (Sweden)

    Mohamed A. Hamed

    2017-03-01

    Full Text Available Trihalomethanes have been identified as the most important disinfection byproducts resulted from using chlorine in desalination plants. Nuweibaa desalination plant was chosen to study their effluents impacts on the marine environment in front of the plant in the coastal area of Gulf of Aqaba. Surface and bottom Water Samples were collected from nine locations in the outfall area of this desalination plant during spring and autumn 2014, and analyzed for water temperature, pH value, Salinity, Dissolved Oxygen, Biological oxygen demand, Oxidizible organic matter, Total, fixed and volatile suspended matter, residual chlorine (free and combined and trihalomethanes. High total chlorine dosage discharged from the desalination plant achieved high levels of trihalomethanes in the receiving seawater of the outfall area. It has been estimated that about 14524.65671 kg of BOD, 74123.4 kg of OOM, 166896.4375 kg of total suspended solids, 623.634 kg of free chlorine, 469.21 kg of combined chlorine, 206.64 kg of chloroform and 76.48 kg of bromoform are discharged annually from this plant into the Gulf of Aqaba affecting the marine ecosystems. The results of THMs showed that the two main forms of THMs formed in the receiving seawater were chloroform and bromoform and ranged between (5.09–156.59, (2.82–566.06 μg/L respectively. High pH and High combined chlorine concentrations favored the formation of high concentrations of chloroform.

  3. 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.

  4. Response surface model for the reduction of Salmonella biofilm on stainless steel with lactic acid, ethanol and chlorine as controlling factors

    Science.gov (United States)

    Bacterial colonization and biofilm formation on food contact surfaces can be sources of contamination of processed foods and poses a serious threat to health. Since chlorine- or ethanol-based disinfection is commonly used in the food industry and kitchens, a disinfectant containing chlorine (Cl), et...

  5. Alternative disinfection technology for water purification systems; Josui shori ni okeru enso daitai shodoku gijutsu

    Energy Technology Data Exchange (ETDEWEB)

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

    1998-09-10

    This paper describes chlorination substituting disinfection technologies used in water purification systems. Chloramine treatment is regarded as effective in reducing trihalomethane (THM). Chlorine is injected in the initial stage in the form of free chlorine to disinfect pathogenic microorganisms in a short time, which is then added with ammonia to convert it into chloramine for further utilization. Chlorine dioxide has not been used in Japan, but introduced in Europe and America to treat THM. Ozone has the strongest oxidizing power, and is used for disinfection, virus inactivation, decomposition of THM precursors, and removal of fungus odor. The ozone treatment will produce aldehyde if an organic matter is present, but aldehyde can be removed by treatment using organismic activated carbon. Ultraviolet ray treatment has an advantage of being difficult of producing byproducts. This system was experimentally compared with free chlorine treatment on disinfection effect, mutagenicity, suppression of producing THM byproducts, and odor removal. In order to assure reliability of microorganismic and chemical safety in tap water supply systems, assurance by considering the entire system is important, not only by operating the disinfection units, but also combining such physical water purifying technologies as coagulation, sedimentation, filtration, and membrane treatment. The use of chlorine substituting disinfectants is also a part of the conception. 6 refs., 8 figs., 5 tabs.

  6. 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).

  7. Chlorine inactivation of fungal spores on cereal grains.

    Science.gov (United States)

    Andrews, S; Pardoel, D; Harun, A; Treloar, T

    1997-04-01

    Although 0.4% chlorine for 2 min has been recommended for surface disinfection of food samples before direct plating for fungal enumeration, this procedure may not be adequate for highly contaminated products. The effectiveness of a range of chlorine solutions was investigated using barley samples artificially contaminated with four different concentrations of Aspergillus flavus. A. niger, A. ochraceus, Eurotium repens, Penicillium brevicompactum P. chrysogenum and Cladosporium cladosporioides. At initial contamination levels greater than 10(4)/g, 0.4% chlorine did not inactivate sufficient spores to produce less than 20% contamination. Of the test fungi, ascospores of E. repens were the most resistant to chlorine inactivation, whereas the conidia of C. cladosporioides were the most sensitive. Rinsing the samples with 70% ethanol improved the effectiveness of the recommended surface disinfection procedure. However, some ethanol appears to permeate into the grains and may inactivate sensitive internal fungi, although a minimal effect only was observed on wheat infected with Alternaria.

  8. 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

  9. Biomonitoring of human exposures to chlorinated derivatives and structural analogs of bisphenol A

    NARCIS (Netherlands)

    Andra, Syam S.; Charisiadis, Pantelis; Arora, Manish; van Vliet-Ostaptchouk, Jana V.; Makris, Konstantinos C.

    2015-01-01

    The high reactivity of bisphenol A (BPA) with disinfectant chlorine is evident in the instantaneous formation of chlorinated BPA derivatives (Cl(x)BPA) in various environmental media that show increased estrogen-activity when compared with that of BPA. The documented health risks associated with BPA

  10. Chlorine: Is it really so bad and what are the alternatives? | Nozaic ...

    African Journals Online (AJOL)

    Chlorine disinfection has been practised for over a century and has been credited with saving a significant number of lives worldwide on a daily basis, but it has received a great deal of negative publicity over the past few decades. The discovery in the 1970\\'s that chlorination of water could result in the formation of ...

  11. Bioremediation of chlorinated ethenes in aquifer thermal energy storage

    NARCIS (Netherlands)

    Ni, Z.

    2015-01-01

    Subjects: bioremediation; biodegradation; environmental biotechnology, subsurface and groundwater contamination; biological processes; geochemistry; microbiology

    The combination of enhanced natural attenuation (ENA) of chlorinated volatile organic compounds

  12. New model of chlorine-wall reaction for simulating chlorine concentration in drinking water distribution systems.

    Science.gov (United States)

    Fisher, Ian; Kastl, George; Sathasivan, Arumugam

    2017-11-15

    Accurate modelling of chlorine concentrations throughout a drinking water system needs sound mathematical descriptions of decay mechanisms in bulk water and at pipe walls. Wall-reaction rates along pipelines in three different systems were calculated from differences between field chlorine profiles and accurately modelled bulk decay. Lined pipes with sufficiently large diameters (>500 mm) and higher chlorine concentrations (>0.5 mg/L) had negligible wall-decay rates, compared with bulk-decay rates. Further downstream, wall-reaction rate consistently increased (peaking around 0.15 mg/dm 2 /h) as chlorine concentration decreased, until mass-transport to the wall was controlling wall reaction. These results contradict wall-reaction models, including those incorporated in the EPANET software, which assume wall decay is of either zero-order (constant decay rate) or first-order (wall-decay rate reduces with chlorine concentration). Instead, results are consistent with facilitation of the wall reaction by biofilm activity, rather than surficial chemical reactions. A new model of wall reaction combines the effect of biofilm activity moderated by chlorine concentration and mass-transport limitation. This wall reaction model, with an accurate bulk chlorine decay model, is essential for sufficiently accurate prediction of chlorine residuals towards the end of distribution systems and therefore control of microbial contamination. Implementing this model in EPANET-MSX (or similar) software enables the accurate chlorine modelling required for improving disinfection strategies in drinking water networks. New insight into the effect of chlorine on biofilm can also assist in controlling biofilm to maintain chlorine residuals. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Development of a Chlorine Dosing Strategy for Fresh Produce Washing Process to Maintain Microbial Food Safety and Minimize Residual Chlorine.

    Science.gov (United States)

    Chen, Xi; Hung, Yen-Con

    2018-05-22

    The residual free chlorine level in fresh produce wash solution is closely correlated to the chemical and microbial safety of produce. Excess amount of free chlorine can quickly react with organic matters to form hazardous disinfection by-products (DBPs) above EPA-permitted levels, whereas deficiency of residual chlorine in produce wash solution may result in incompletely removing pathogens on produce. The purpose of this study was to develop a chlorine dosing strategy to optimize the chlorine dosage during produce washing process without impacting the microbial safety of fresh produce. Prediction equations were developed to estimate free chlorine needed to reach targeted residual chlorine at various sanitizer pH and organic loads, and then validated using fresh-cut iceberg lettuce and whole strawberries in an automated produce washer. Validation results showed that equations successfully predicted the initial chlorine concentration needed to achieve residual chlorine at 10, 30, 60, and 90 mg/L for both lettuce and strawberry washing processes, with the root mean squared error at 4.45 mg/L. The Escherichia coli O157:H7 reductions only slightly increased on iceberg lettuce and strawberries with residual chlorine increasing from 10 to 90 mg/L, indicating that lowering residual chlorine to 10 mg/L would not compromise the antimicrobial efficacy of chlorine-based sanitizer. Based on the prediction equations and E. coli O157:H7 reduction results, a chlorine dosing strategy was developed to help the produce industry to maintain microbial inactivation efficacy without adding excess amount of free chlorine. The chlorine dosing strategy can be used for fresh produce washing process to enhance the microbial food safety and minimize the DBPs formation potential. © 2018 Institute of Food Technologists®.

  14. 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.

  15. Study of sequential disinfection for the inactivation of protozoa and indicator microorganisms in wastewater

    Directory of Open Access Journals (Sweden)

    Raphael Corrêa Medeiros

    2015-05-01

    Full Text Available Sewage disinfection has the primary objective of inactivating pathogenic organisms to prevent the dissemination of waterborne diseases. This study analyzed individual disinfection, with chlorine and ultraviolet radiation, and sequential disinfection (chlorine-UV radiation. The tests were conducted with anaerobic effluent in batch, in laboratory scale, with two dosages of chlorine (10 and 20 mg L-1 and UV (2.5 and 6.1 Wh m-3. In addition, to guarantee the presence of cysts in the tests, 104 cysts per liter of Giardia spp. were inoculated. The resistance order was as follows: E. coli = Total Coliforms < Clostridium perfringens < Giardia spp.. Furthermore, synergistic effects reached 0.06 to 1.42 log of inactivation in sequential disinfection for both the most resistant microorganisms.

  16. Fate of free chlorine in drinking water during distribution in premise plumbing.

    Science.gov (United States)

    Zheng, Muzi; He, Chunguang; He, Qiang

    2015-12-01

    Free chlorine is a potent oxidizing agent and has been used extensively as a disinfectant in processes including water treatment. The presence of free chlorine residual is essential for the prevention of microbial regrowth in water distribution systems. However, excessive levels of free chlorine can cause adverse health effects. It is a major challenge to maintain appropriate levels of free chlorine residual in premise plumbing. As the first effort to assessing the fate of chlorine in premise plumbing using actual premise plumbing pipe sections, three piping materials frequently used in premise plumbing, i.e. copper, galvanized iron, and polyvinyl chloride (PVC), were investigated for their performance in maintaining free chlorine residual. Free chlorine decay was shown to follow first-order kinetics for all three pipe materials tested. The most rapid chlorine decay was observed in copper pipes, suggesting the need for higher chlorine dosage to maintain appropriate levels of free chlorine residual if copper piping is used. PVC pipes exhibited the least reactivity with free chlorine, indicative of the advantage of PVC as a premise plumbing material for maintaining free chlorine residual. The reactivity of copper piping with free chlorine was significantly hindered by the accumulation of pipe deposits. In contrast, the impact on chlorine decay by pipe deposits was not significant in galvanized iron and PVC pipes. Findings in this study are of great importance for the development of effective strategies for the control of free chlorine residual and prevention of microbiological contamination in premise plumbing.

  17. Irradiation as an alternative for disinfection of domestic waste in the Canadian Arctic

    International Nuclear Information System (INIS)

    1981-01-01

    This study evaluated the technical and economic feasibility of various methods for disinfecting wastewater in the Canadian Arctic with specific reference to gamma radiation. More conventional disinfection practices, such as chlorination, chlorination-dechlorination, and ozonation were compared to gamma radiation along with ultraviolet irradiation and lime disinfection. The quality of lagoon effluent, highly diluted (weak) sewage, holding tank wastes and honey-bag wastes, which are the typical waste types found in northern communities, was established from data available in the literature. Further literature reviews were undertaken to establish a data base for design and effectiveness of disinfection systems operated in cold climates. Capital and operating costs for all technically feasible disinfection process alternates were estimated based on historical cost data adjusted to 1977 for the construction and instalation of similar systems in the north. The costs of equipment, chemicals, fuel and electrical power were obtained from suppliers. The environmental impact of each of the disinfection processes was reviewed with emphasis on gamma irradiation. Safety and health aspects were also considered. The study concluded that gamma irradiation was capable of providing safe, reliable disinfection for concentrated honey-bag and holding wastes. Pilot-scale testing was recommended prior to construction of full-scale disinfection facilities. For lagoon effluents and weak sewage, gamma irradiation was not cost competitive with other alternates; rather chlorination-dechlorination was found to be the most cost-effective and environmentally acceptable alternative

  18. 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.

  19. The Dependence of Chlorine Decay and DBP Formation Kinetics On Pipe Flow Properties in Drinking Water Distribution

    Science.gov (United States)

    Simultaneous chlorine decay and disinfection byproduct (DBP) formation has long been discussed because of its regulatory and operational significance. This study further examines the water quality changes under hydrodynamic settings during drinking water distribution. Comparative...

  20. State of the art on cyanotoxins in water and their behaviour towards chlorine.

    Science.gov (United States)

    Merel, Sylvain; Clément, Michel; Thomas, Olivier

    2010-04-01

    The occurrence of cyanobacterial blooms is drastically increasing in temperate countries and drinking water resources are threatened. As a result, cyanotoxins should be considered in water treatment to protect human health. This study presents a state of the art on cyanotoxins in water and their behaviour towards chlorination, a common drinking water disinfection process. Chlorination efficiency on cyanotoxins alteration depends on pH, chlorine dose and oxidant nature. Microcystins and cylindrospermopsin are efficiently transformed by chlorine, with respectively 6 and 2 by-products identified. In addition, chlorination of microcystins and cylindrospermopsin is associated with a loss of acute toxicity. Even though they have been less investigated, saxitoxins and nodularins are also altered by chlorine. For these toxins, no by-products have been identified, but the chlorinated mixture does not show acute toxicity. On the contrary, the fact that anatoxin-a has a very slow reaction kinetics suggests that this toxin resists chlorination. Copyright 2009 Elsevier Ltd. All rights reserved.

  1. Chlorine stress mediates microbial surface attachment in drinking water systems.

    Science.gov (United States)

    Liu, Li; Le, Yang; Jin, Juliang; Zhou, Yuliang; Chen, Guowei

    2015-03-01

    Microbial attachment to drinking water pipe surfaces facilitates pathogen survival and deteriorates disinfection performance, directly threatening the safety of drinking water. Notwithstanding that the formation of biofilm has been studied for decades, the underlying mechanisms for the origins of microbial surface attachment in biofilm development in drinking water pipelines remain largely elusive. We combined experimental and mathematical methods to investigate the role of environmental stress-mediated cell motility on microbial surface attachment in chlorination-stressed drinking water distribution systems. Results show that at low levels of disinfectant (0.0-1.0 mg/L), the presence of chlorine promotes initiation of microbial surface attachment, while higher amounts of disinfectant (>1.0 mg/L) inhibit microbial attachment. The proposed mathematical model further demonstrates that chlorination stress (0.0-5.0 mg/L)-mediated microbial cell motility regulates the frequency of cell-wall collision and thereby controls initial microbial surface attachment. The results reveal that transport processes and decay patterns of chlorine in drinking water pipelines regulate microbial cell motility and, thus, control initial surface cell attachment. It provides a mechanistic understanding of microbial attachment shaped by environmental disinfection stress and leads to new insights into microbial safety protocols in water distribution systems.

  2. 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

  3. The efficiency of water treatment and disinfection by means of ultraviolet radiation

    International Nuclear Information System (INIS)

    Sobotka, J.

    1993-01-01

    Advantages and disadvantages of various water disinfection methods are discussed. The report examines the effectiveness of combined chlorine treatment and UV irradiation method of water disinfection and describes methods of determining UV radiation intensity, α absorption coefficient and radiation dose by means of measuring equipment constructed by the author. The α absorption coefficient dependence on the colour and turbidity of water exposed to radiation is defined. Enchytraeus albidus was applied as bioindicator in UV radiation intensity and disinfection effects measurements. The influence of UV radiation on microbiological, physical, chemical, and toxicological properties of water was determined. Prototype devices for water disinfection with UV radiation were made. (author)

  4. The efficiency of water treatment and disinfection by means of ultraviolet radiation

    Energy Technology Data Exchange (ETDEWEB)

    Sobotka, J [Medical Academy, Warsaw (Poland). Inst. of Social Medicine

    1993-01-01

    Advantages and disadvantages of various water disinfection methods are discussed. The report examines the effectiveness of combined chlorine treatment and UV irradiation method of water disinfection and describes methods of determining UV radiation intensity, [alpha] absorption coefficient and radiation dose by means of measuring equipment constructed by the author. The [alpha] absorption coefficient dependence on the colour and turbidity of water exposed to radiation is defined. Enchytraeus albidus was applied as bioindicator in UV radiation intensity and disinfection effects measurements. The influence of UV radiation on microbiological, physical, chemical, and toxicological properties of water was determined. Prototype devices for water disinfection with UV radiation were made. (author).

  5. ASCORBIC ACID REDUCTION OF ACTIVE CHLORINE PRIOR TO DETERMINING AMES MUTAGENICITY OF CHLORINATED NATURAL ORGANIC MATTER (NOM)

    Science.gov (United States)

    Many potable water disinfection byproducts (DBPs) that result from the reaction of natural organic matter (NOM) with oxidizing chlorine are known or suspected to be carcinogenic and mutagenic. The Ames assay is routinely used to assess an overall level of mutagenicity for all com...

  6. The hydrogen concentration as parameter to identify natural attenuation processes of volatile chlorinated hydrocarbons in ground water; Die Wasserstoffkonzentration als Parameter zur Identifizierung des natuerlichen Abbaus von leichtfluechtigen Chlorkohlenwasserstoffen (LCKW) im Grundwasser

    Energy Technology Data Exchange (ETDEWEB)

    Alter, M.D.

    2006-06-15

    In this study, the hydrogen concentration as parameter to identify natural attenuation processes of volatile chlorinated hydrocarbons was investigated. The currently accepted and recommended bubble strip method for hydrogen sampling was optimized, and a storage method for hydrogen samples was developed. Furthermore batch experiments with a dechlorinating mixed culture and pure cultures were carried out to study H{sub 2}-concentrations of competing redox processes. The extraction of hydrogen from ground water was optimized by a reduced inlet diameter of the usually applied gas sampling bulbs, allowing a maximal turbulent ow and gas transfer. With a gas volume of 10 ml and flow rates of 50 to 140 ml/min, the course of extraction almost followed the theoretical course of equilibration. At flow rates > 100 ml/min a equilibrium of 98% was achieved within 20 min. Until recently it was generally accepted that hydrogen samples can be stored only for 2 hours and therefore have to be analyzed immediately in the eld. Here, it was shown that eld samples can be stored for 1-3 days until analysis. For the dechlorination of tetrachloroethene (PCE), a hydrogen threshold concentration of 1-2 nM was found with the dechlorinating mixed culture as well as with a pure culture of Sulfurospirillum multivorans in combination with another pure culture Methanosarcina mazei. No dechlorination was detectable below this concentration. With the dechlorinating mixed culture, this finding is valid for all successive dechlorination steps until ethene. The hydrogen threshold concentration for denitrification were below the detection limit of 0,2 nM with the dechlorinating mixed culture. A threshold concentration of 3,1-3,5 nM was found for sulphate reduction and a threshold of 7-9 nM H{sub 2} for hydrogenotrophic methanogenesis. This implies that the natural dechlorination at contaminated sites is preferred to competing processes like sulphate reduction and methanogenesis. The threshold

  7. Resistance and Inactivation Kinetics of Bacterial Strains Isolated from the Non-Chlorinated and Chlorinated Effluents of a WWTP

    Directory of Open Access Journals (Sweden)

    Claudia Coronel-Olivares

    2013-08-01

    Full Text Available The microbiological quality of water from a wastewater treatment plant that uses sodium hypochlorite as a disinfectant was assessed. Mesophilic aerobic bacteria were not removed efficiently. This fact allowed for the isolation of several bacterial strains from the effluents. Molecular identification indicated that the strains were related to Aeromonas hydrophila, Escherichia coli (three strains, Enterobacter cloacae, Kluyvera cryocrescens (three strains, Kluyvera intermedia, Citrobacter freundii (two strains, Bacillus sp. and Enterobacter sp. The first five strains, which were isolated from the non-chlorinated effluent, were used to test resistance to chlorine disinfection using three sets of variables: disinfectant concentration (8, 20 and 30 mg·L−1, contact time (0, 15 and 30 min and water temperature (20, 25 and 30 °C. The results demonstrated that the strains have independent responses to experimental conditions and that the most efficient treatment was an 8 mg·L−1 dose of disinfectant at a temperature of 20 °C for 30 min. The other eight strains, which were isolated from the chlorinated effluent, were used to analyze inactivation kinetics using the disinfectant at a dose of 15 mg·L−1 with various retention times (0, 10, 20, 30, 60 and 90 min. The results indicated that during the inactivation process, there was no relationship between removal percentage and retention time and that the strains have no common response to the treatments.

  8. Sequential and Simultaneous Applications of UV and Chlorine for Adenovirus Inactivation.

    Science.gov (United States)

    Rattanakul, Surapong; Oguma, Kumiko; Takizawa, Satoshi

    2015-09-01

    Adenoviruses are water-borne human pathogens with high resistance to UV disinfection. Combination of UV treatment and chlorination could be an effective approach to deal with adenoviruses. In this study, human adenovirus 5 (HAdV-5) was challenged in a bench-scale experiment by separate applications of UV or chlorine and by combined applications of UV and chlorine in either a sequential or simultaneous manner. The treated samples were then propagated in human lung carcinoma epithelial cells to quantify the log inactivation of HAdV-5. When the processes were separate, a fluence of 100 mJ/cm(2) and a CT value of 0.02 mg min/L were required to achieve 2 log inactivation of HAdV-5 by UV disinfection and chlorination, respectively. Interestingly, synergistic effects on the HAdV-5 inactivation rates were found in the sequential process of chlorine followed by UV (Cl2-UV) (p simultaneous application of UV/Cl2. This implies that a pretreatment with chlorine may increase the sensitivity of the virus to the subsequent UV disinfection. In conclusion, this study suggests that the combined application of UV and chlorine could be an effective measure against adenoviruses as a multi-barrier approach in water disinfection.

  9. 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...

  10. 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

  11. 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.

  12. Effects of operating conditions on THMs and HAAs formation during wastewater chlorination

    Energy Technology Data Exchange (ETDEWEB)

    Sun Yingxue; Wu Qianyuan [Environmental Simulation and Pollution Control State Key Joint Laboratory, Department of Environmental Science and Engineering, Tsinghua University, Beijing 100084 (China); Hu Hongying, E-mail: hyhu@tsinghua.edu.cn [Environmental Simulation and Pollution Control State Key Joint Laboratory, Department of Environmental Science and Engineering, Tsinghua University, Beijing 100084 (China); Tian Jie [Environmental Simulation and Pollution Control State Key Joint Laboratory, Department of Environmental Science and Engineering, Tsinghua University, Beijing 100084 (China)

    2009-09-15

    Disinfection is the last barrier of wastewater reclamation process to protect ecosystem safety and human health. However, the chlorination process results in the formation of mutagenic/carcinogenic disinfection by-products (DBPs) deriving from the reaction of the chlorine with organic compounds in wastewater. The effects of operating conditions (chlorine dose, contact time, reaction temperature and pH value) of chlorination on the formation of trihalomethanes (THMs) and haloacetic acids (HAAs) in biologically treated wastewater samples were investigated in this study. The results indicated that the total THMs (TTHM) and total HAAs (THAA) increased exponentially with increasing chlorine dose, but there are discrepancies between the formation rates of TTHM and THAA. The THAA reached a peak at contact time of 2 h and thereafter decreased with extended time. The formation time of THMs depends on the wastewater content of quick or slow formers. The yields of bromated HAAs (as MBAA, BCAA, and BDCAA) would decrease markedly after the contact time over 2 h during wastewater chlorination, and were favored in low pH values of 4 and high pH values of 9 under certain contact time. In addition, the formation of MBAA, BCAA, BDCAA decreased gradually as reaction temperature increased from 4 to 30 deg. C in the chlorination of wastewater containing a certain concentration of bromide. The effects of operating conditions on THMs and HAAs formation during wastewater chlorination were completely different from those of surface water disinfection.

  13. Effects of operating conditions on THMs and HAAs formation during wastewater chlorination

    International Nuclear Information System (INIS)

    Sun Yingxue; Wu Qianyuan; Hu Hongying; Tian Jie

    2009-01-01

    Disinfection is the last barrier of wastewater reclamation process to protect ecosystem safety and human health. However, the chlorination process results in the formation of mutagenic/carcinogenic disinfection by-products (DBPs) deriving from the reaction of the chlorine with organic compounds in wastewater. The effects of operating conditions (chlorine dose, contact time, reaction temperature and pH value) of chlorination on the formation of trihalomethanes (THMs) and haloacetic acids (HAAs) in biologically treated wastewater samples were investigated in this study. The results indicated that the total THMs (TTHM) and total HAAs (THAA) increased exponentially with increasing chlorine dose, but there are discrepancies between the formation rates of TTHM and THAA. The THAA reached a peak at contact time of 2 h and thereafter decreased with extended time. The formation time of THMs depends on the wastewater content of quick or slow formers. The yields of bromated HAAs (as MBAA, BCAA, and BDCAA) would decrease markedly after the contact time over 2 h during wastewater chlorination, and were favored in low pH values of 4 and high pH values of 9 under certain contact time. In addition, the formation of MBAA, BCAA, BDCAA decreased gradually as reaction temperature increased from 4 to 30 deg. C in the chlorination of wastewater containing a certain concentration of bromide. The effects of operating conditions on THMs and HAAs formation during wastewater chlorination were completely different from those of surface water disinfection.

  14. Chlorination of organophosphorus pesticides in natural waters

    Energy Technology Data Exchange (ETDEWEB)

    Acero, Juan L. [Departamento de Ingenieria Quimica y Energetica, Universidad de Extremadura, 06071 Badajoz (Spain)], E-mail: jlacero@unex.es; Benitez, F. Javier; Real, Francisco J.; Gonzalez, Manuel [Departamento de Ingenieria Quimica y Energetica, Universidad de Extremadura, 06071 Badajoz (Spain)

    2008-05-01

    Unknown second-order rate constants for the reactions of three organophosphorus pesticides (chlorpyrifos, chlorfenvinfos and diazinon) with chlorine were determined in the present study, and the influence of pH and temperature was established. It was found that an increase in the pH provides a negative effect on the pesticides degradation rates. Apparent second-order rate constants at 20 {sup o}C and pH 7 were determined to be 110.9, 0.004 and 191.6 M{sup -1} s{sup -1} for chlorpyrifos, chlorfenvinfos and diazinon, respectively. A higher reactivity of chlorine with the phosphorothioate group (chlorpyrifos and diazinon) than with the phosphate moiety (chlorfenvinfos) could explain these results. Intrinsic rate constant for the elementary reactions of chlorine species with chlorpyrifos and diazinon were also calculated, leading to the conclusion that the reaction between hypochlorous acid and the pesticide is predominant at neutral pH. The elimination of these pesticides in surface waters was also investigated. A chlorine dose of 2.5 mg L{sup -1} was enough to oxidize chlorpyrifos and diazinon almost completely, with a formation of trihalomethanes below the EU standard for drinking water. However, the removal of chlorfenvinfos was not appreciable. Therefore, chlorination is a feasible option for the removal of organophosphorus pesticides with phosphorothioate group during oxidation and disinfection processes, but not for the elimination of pesticides with phosphate moiety.

  15. Chlorination of organophosphorus pesticides in natural waters

    International Nuclear Information System (INIS)

    Acero, Juan L.; Benitez, F. Javier; Real, Francisco J.; Gonzalez, Manuel

    2008-01-01

    Unknown second-order rate constants for the reactions of three organophosphorus pesticides (chlorpyrifos, chlorfenvinfos and diazinon) with chlorine were determined in the present study, and the influence of pH and temperature was established. It was found that an increase in the pH provides a negative effect on the pesticides degradation rates. Apparent second-order rate constants at 20 o C and pH 7 were determined to be 110.9, 0.004 and 191.6 M -1 s -1 for chlorpyrifos, chlorfenvinfos and diazinon, respectively. A higher reactivity of chlorine with the phosphorothioate group (chlorpyrifos and diazinon) than with the phosphate moiety (chlorfenvinfos) could explain these results. Intrinsic rate constant for the elementary reactions of chlorine species with chlorpyrifos and diazinon were also calculated, leading to the conclusion that the reaction between hypochlorous acid and the pesticide is predominant at neutral pH. The elimination of these pesticides in surface waters was also investigated. A chlorine dose of 2.5 mg L -1 was enough to oxidize chlorpyrifos and diazinon almost completely, with a formation of trihalomethanes below the EU standard for drinking water. However, the removal of chlorfenvinfos was not appreciable. Therefore, chlorination is a feasible option for the removal of organophosphorus pesticides with phosphorothioate group during oxidation and disinfection processes, but not for the elimination of pesticides with phosphate moiety

  16. Chlorine in the stratosphere

    OpenAIRE

    VON CLARMANN, T.

    2013-01-01

    This paper reviews the various aspects of chlorine compounds in the stratosphere, both their roles as reactants and as tracers of dynamical processes. In the stratosphere, reactive chlorine is released from chlorofluorocarbons and other chlorine-containing organic source gases. To a large extent reactive chlorine is then sequestered in reservoir species ClONO2 and HCl. Re-activation of chlorine happens predominantly in polar winter vortices by heterogeneous reaction in combination with sunlig...

  17. Thermal disinfection of hotels, hospitals, and athletic venues hot water distribution systems contaminated by Legionella species.

    Science.gov (United States)

    Mouchtouri, Varvara; Velonakis, Emmanuel; Hadjichristodoulou, Christos

    2007-11-01

    Legionella spp. (> or = 500 cfu liter(-1)) were detected in 92 of 497 water distribution systems (WDS) examined. Thermal disinfection was applied at 33 WDS. After the first and second application of the disinfection procedure, 15 (45.4%) and 3 (9%) positive for remedial actions WDS were found, respectively. Legionella pneumophila was more resistant to thermal disinfection than Legionella non-pneumophila spp. (relative risk [RR]=5.4, 95% confidence intervals [CI]=1-35). WDS of hotels with oil heater were more easily disinfected than those with electrical or solar heater (RR=0.4 95% CI=0.2-0.8). Thermal disinfection seems not to be efficient enough to eliminate legionellae, unless repeatedly applied and in combination with extended heat flushing, and faucets chlorine disinfection.

  18. Transformation of cefazolin during chlorination process: Products, mechanism and genotoxicity assessment

    Energy Technology Data Exchange (ETDEWEB)

    Li, Liping, E-mail: lisaleercees807@yahoo.cn; Wei, Dongbin, E-mail: weidb@rcees.ac.cn; Wei, Guohua, E-mail: wgh@rcees.ac.cn; Du, Yuguo, E-mail: duyuguo@rcees.ac.cn

    2013-11-15

    Highlights: • Base-catalyzed electrophilic substitution occurred in cefazolin chlorination. • Oxidation of thioether in cefazolin was found in chlorination process. • The pH conditions impacted on the occurrence of reaction types. • Genotoxicity had an elevation after chlorination of cefazolin. • Reaction pathways of cefazolin chlorination were replayed in surface water matrix. -- Abstract: Large quantities of cephalosporins have entered into aquatic environment in recent years, posing potential adverse effect to human health and ecological safety. In this study, cefazolin, one of widely used cephalosporins, was targeted to explore its transformation behaviors in chlorination disinfection process. With the help of ultra high performance liquid chromatography and high resolution mass spectroscopy, one chlorinated product and four oxidation products were detected in cefazolin chlorination system. The corresponding transformation pathways of cefazolin were proposed. Two kinds of reactions occurred in chlorination system, one was oxidation of thioether-sulfur to sulfoxide and di-sulfoxide, and the other was base-catalyzed electrophilic substitution of alpha-H of amide by chlorine atom. The pH value determined the occurrence of reaction types, and increasing chlorine dose promoted transformation of cefazolin. More importantly, genotoxicity in SOS/umu assay had an elevation after chlorination, which might be attributed to the formation of chlorinated product and sulfoxide during chlorination process.

  19. Transformation of cefazolin during chlorination process: Products, mechanism and genotoxicity assessment

    International Nuclear Information System (INIS)

    Li, Liping; Wei, Dongbin; Wei, Guohua; Du, Yuguo

    2013-01-01

    Highlights: • Base-catalyzed electrophilic substitution occurred in cefazolin chlorination. • Oxidation of thioether in cefazolin was found in chlorination process. • The pH conditions impacted on the occurrence of reaction types. • Genotoxicity had an elevation after chlorination of cefazolin. • Reaction pathways of cefazolin chlorination were replayed in surface water matrix. -- Abstract: Large quantities of cephalosporins have entered into aquatic environment in recent years, posing potential adverse effect to human health and ecological safety. In this study, cefazolin, one of widely used cephalosporins, was targeted to explore its transformation behaviors in chlorination disinfection process. With the help of ultra high performance liquid chromatography and high resolution mass spectroscopy, one chlorinated product and four oxidation products were detected in cefazolin chlorination system. The corresponding transformation pathways of cefazolin were proposed. Two kinds of reactions occurred in chlorination system, one was oxidation of thioether-sulfur to sulfoxide and di-sulfoxide, and the other was base-catalyzed electrophilic substitution of alpha-H of amide by chlorine atom. The pH value determined the occurrence of reaction types, and increasing chlorine dose promoted transformation of cefazolin. More importantly, genotoxicity in SOS/umu assay had an elevation after chlorination, which might be attributed to the formation of chlorinated product and sulfoxide during chlorination process

  20. Susceptibility of Legionella pneumophila to chlorine in tap water.

    Science.gov (United States)

    Kuchta, J M; States, S J; McNamara, A M; Wadowsky, R M; Yee, R B

    1983-11-01

    A study was conducted to compare the susceptibility of legionellae and coliforms to disinfection by chlorine. The chlorine residuals used were similar to concentrations that might be found in the distribution systems of large public potable water supplies. The effects of various chlorine concentrations, temperatures, and pH levels were considered. A number of different Legionella strains, both environmental and clinical, were tested. The results indicate that legionellae are much more resistant to chlorine than are coliform bacteria. At 21 degrees C, pH 7.6, and 0.1 mg of free chlorine residual per liter, a 99% kill of L. pneumophila was achieved within 40 min, compared with less than 1 min for Escherichia coli. The observed resistance is enhanced as conditions for disinfection become less optimal. The required contact time for the removal of L. pneumophilia was twice as long at 4 degrees C than it was at 21 degrees C. These data suggest that legionellae can survive low levels of chlorine for relatively long periods of time.

  1. 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.

  2. Turbidity and chlorine demand reduction using alum and moringa flocculation before household chlorination in developing countries.

    Science.gov (United States)

    Preston, Kelsey; Lantagne, Daniele; Kotlarz, Nadine; Jellison, Kristen

    2010-03-01

    Over 1.1 billion people in the world lack access to improved drinking water. Diarrhoeal and other waterborne diseases cause an estimated 1.87 million deaths per year. The Safe Water System (SWS) is a household water treatment intervention that reduces diarrhoeal disease incidence among users in developing countries. Turbid waters pose a particular challenge to implementation of SWS programmes; although research shows that a 3.75 mg l(-1) sodium hypochlorite dose effectively treats turbid waters, users sometimes object to the strong chlorine taste and prefer to drink water that is more aesthetically pleasing. This study investigated the efficacy of two locally available chemical water treatments-alum and Moringa oleifera flocculation-to reduce turbidity and chlorine demand at turbidities of 10, 30, 70, 100 and 300 NTU. Both treatments effectively reduced turbidity (alum flocculation 23.0-91.4%; moringa flocculation 14.2-96.2%). Alum flocculation effectively reduced chlorine demand compared with controls at 30, 70, 100 and 300 NTU (p=0.01-0.06). Moringa flocculation increased chlorine demand to the point where adequate free chlorine residual was not maintained for 24 hours after treatment. Alum pretreatment is recommended in waters>or=30 NTU for optimum water disinfection. Moringa flocculation is not recommended before chlorination.

  3. 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.

  4. 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.

  5. 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

  6. DBP formation from degradation of DEET and ibuprofen by UV/chlorine process and subsequent post-chlorination.

    Science.gov (United States)

    Aghdam, Ehsan; Xiang, Yingying; Sun, Jianliang; Shang, Chii; Yang, Xin; Fang, Jingyun

    2017-08-01

    The formation of disinfection by-products (DBPs) from the degradation of N,N-diethyl-3-methyl benzoyl amide (DEET) and ibuprofen (IBP) by the ultraviolet irradiation (UV)/chlorine process and subsequent post-chlorination was investigated and compared with the UV/H 2 O 2 process. The pseudo first-order rate constants of the degradation of DEET and IBP by the UV/chlorine process were 2 and 3.1 times higher than those by the UV/H 2 O 2 process, respectively, under the tested conditions. This was due to the significant contributions of both reactive chlorine species (RCS) and hydroxyl radicals (HO) in the UV/chlorine process. Trichloromethane, 1,1,1-trichloro-2-propanone and dichloroacetic acid were the major known DBPs formed after 90% of both DEET and IBP that were degraded by the UV/chlorine process. Their yields increased by over 50% after subsequent 1-day post-chlorination. The detected DBPs after the degradation of DEET and IBP comprised 13.5% and 19.8% of total organic chlorine (TOCl), respectively, and the proportions increased to 19.8% and 33.9% after subsequent chlorination, respectively. In comparison to the UV/H 2 O 2 process accompanied with post-chlorination, the formation of DBPs and TOCl in the UV/chlorine process together with post-chlorination was 5%-63% higher, likely due to the generation of more DBP precursors from the attack of RCS, in addition to HO. Copyright © 2017. Published by Elsevier B.V.

  7. SOME ASPECTS REGARING CHLORINE DECAY IN WATER DISTRIBUTION NETWORKS

    Directory of Open Access Journals (Sweden)

    LIANA IOANA VUŢĂ

    2011-03-01

    Full Text Available A major objective of drinking water treatment is to provide microbiologically safe drinking water. The combination of conventional drinking water treatment and disinfection has proved to be one of the major public health advances in modern times. The quality of drinking water delivered to the customer’s tap is influenced by a number of processes; namely water treatment, disinfection and changes during transport of treated water via the distribution system. All natural waters and even treated drinking water exerts disinfectant demand due to the reactions with NOM and other constituents in water. Therefore, the applied disinfectant dose must be sufficient to meet the inherent demand in the treated water, to provide sufficient protection against microbial infection. Thus, controlling free residual chlorine properly is definitely important to ensure meeting regulatory requirements and satisfying customer needs.This paper presents the main aspects regarding chlorine decay in drinking-water distribution networks and, also a free chlorine decay simulation with EPANET2 on Ramnicu Valcea water distribution system.

  8. Inhibition of lipopolysaccharide induced acute inflammation in lung by chlorination

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jinshan; Xue, Jinling; Xu, Bi; Xie, Jiani [Environmental Simulation and Pollution Control State Key Joint Laboratory, School of Environment, Tsinghua University, Beijing 100084 (China); Qiao, Juan, E-mail: qjuan@tsinghua.edu.cn [Department of Chemistry, Tsinghua University, Beijing 100084 (China); Lu, Yun, E-mail: luyun@tsinghua.edu.cn [Environmental Simulation and Pollution Control State Key Joint Laboratory, School of Environment, Tsinghua University, Beijing 100084 (China)

    2016-02-13

    Highlights: • Chlorination is effective to reduce the inflammation inducing capacity of LPS in lung. • LAL-detected endotoxin activity is not correlated to the potency of inflammation induction. • Alkyl chain of LPS was chlorinated in chlorination process. • LPS aggregate size decreases after chlorination. - Abstract: Lipopolysaccharide (LPS, also called endotoxin) is a pro-inflammatory constituent of gram negative bacteria and cyanobacteria, which causes a potential health risk in the process of routine urban application of reclaimed water, such as car wash, irrigation, scenic water refilling, etc. Previous studies indicated that the common disinfection treatment, chlorination, has little effect on endotoxin activity removal measured by Limulus amebocyte lysate (LAL) assay. However, in this study, significant decrease of acute inflammatory effects was observed in mouse lung, while LAL assay still presented a moderate increase of endotoxin activity. To explore the possible mechanisms, the nuclear magnetic resonance (NMR) results showed the chlorination happened in alkyl chain of LPS molecules, which could affect the interaction between LPS and LPS-binding protein. Also the size of LPS aggregates was found to drop significantly after treatment, which could be another results of chlorination caused polarity change. In conclusion, our observation demonstrated that chlorination is effective to reduce the LPS induced inflammation in lung, and it is recommended to use health effect-based methods to assess risk removal of water treatment technologies.

  9. Inhibition of lipopolysaccharide induced acute inflammation in lung by chlorination

    International Nuclear Information System (INIS)

    Zhang, Jinshan; Xue, Jinling; Xu, Bi; Xie, Jiani; Qiao, Juan; Lu, Yun

    2016-01-01

    Highlights: • Chlorination is effective to reduce the inflammation inducing capacity of LPS in lung. • LAL-detected endotoxin activity is not correlated to the potency of inflammation induction. • Alkyl chain of LPS was chlorinated in chlorination process. • LPS aggregate size decreases after chlorination. - Abstract: Lipopolysaccharide (LPS, also called endotoxin) is a pro-inflammatory constituent of gram negative bacteria and cyanobacteria, which causes a potential health risk in the process of routine urban application of reclaimed water, such as car wash, irrigation, scenic water refilling, etc. Previous studies indicated that the common disinfection treatment, chlorination, has little effect on endotoxin activity removal measured by Limulus amebocyte lysate (LAL) assay. However, in this study, significant decrease of acute inflammatory effects was observed in mouse lung, while LAL assay still presented a moderate increase of endotoxin activity. To explore the possible mechanisms, the nuclear magnetic resonance (NMR) results showed the chlorination happened in alkyl chain of LPS molecules, which could affect the interaction between LPS and LPS-binding protein. Also the size of LPS aggregates was found to drop significantly after treatment, which could be another results of chlorination caused polarity change. In conclusion, our observation demonstrated that chlorination is effective to reduce the LPS induced inflammation in lung, and it is recommended to use health effect-based methods to assess risk removal of water treatment technologies.

  10. Determining Exposure Factors of Anti-Fogging, Dye, Disinfectant, Repellent, and Preservative Products in Korea.

    Science.gov (United States)

    Lee, Daeyeop; Kim, Joo-Hyon; Kim, Taksoo; Yoon, Hyojung; Jo, Areum; Lee, Byeongwoo; Lim, Hyunwoo; Kim, Pilje; Seo, Jungkwan

    2018-01-30

    Reliable exposure factors are essential to determine health risks posed by chemicals in consumer products. We analyzed five risk-concerned product categories (anti-fogging, dye, disinfectant, repellent, and preservative products) for 13 products (three car anti-fogging products, a lens anti-fogging product, two car dye products, two drain disinfectants, an air conditioner disinfectant, a chlorine-based disinfectant, a fabric repellent, an insect repellent for food, and a wood preservative) considered to be of high risk in order to determine exposure factors via web surveys and estimation of amount of product. Among the 3000 participants (1482 (49%) men) aged ≥19 years, drain disinfectants were used most frequently (38.2%); the rate of usage of the other products ranged between 1.1-24.0%. The usage rates for the consumer products differed by sex, age, income, and education. Some consumer products such as car and lens anti-fogging products, chlorine-based disinfectants, fabric repellents, and drain disinfectants were regularly used more than once a month, while car dye products, air conditioner disinfectants, insect repellents for food, and wood preservatives were not regularly used owing to the specific product purposes and seasonal needs. Our results could be used for managing or controlling chemical substances in consumer products and conducting accurate exposure assessments.

  11. 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

  12. Chlorine inactivation of Tubifex tubifex in drinking water and the synergistic effect of sequential inactivation with UV irradiation and chlorine.

    Science.gov (United States)

    Nie, Xiao-Bao; Li, Zhi-Hong; Long, Yuan-Nan; He, Pan-Pan; Xu, Chao

    2017-06-01

    The inactivation of Tubifex tubifex is important to prevent contamination of drinking water. Chlorine is a widely-used disinfectant and the key factor in the inactivation of T. tubifex. This study investigated the inactivation kinetics of chlorine on T. tubifex and the synergistic effect of the sequential use of chlorine and UV irradiation. The experimental results indicated that the Ct (concentration × time reaction ) concept could be used to evaluate the inactivation kinetics of T. tubifex with chlorine, thus allowing for the use of a simpler Ct approach for the assessment of T. tubifex chlorine inactivation requirements. The inactivation kinetics of T. tubifex by chlorine was found to be well-fitted to a delayed pseudo first-order Chick-Watson expression. Sequential experiments revealed that UV irradiation and chlorine worked synergistically to effectively inactivate T. tubifex as a result of the decreased activation energy, E a , induced by primary UV irradiation. Furthermore, the inactivation effectiveness of T. tubifex by chlorine was found to be affected by several drinking water quality parameters including pH, turbidity, and chemical oxygen demand with potassium permanganate (COD Mn ) concentration. High pH exhibited pronounced inactivation effectiveness and the decrease in turbidity and COD Mn concentrations contributed to the inactivation of T. tubifex. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. VOLATILE CHLORIDE PROCESS FOR THE RECOVERY OF METAL VALUES

    Science.gov (United States)

    Hanley, W.R.

    1959-01-01

    A process is presented for recovering uranium, iron, and aluminum from centain shale type ores which contain uranium in minute quantities. The ore is heated wiih a chlorinating agent. such as chlorine, to form a volatilized stream of metal chlorides. The chloride stream is then passed through granular alumina which preferentially absorbs the volatile uranium chloride and from which the uranium may later be recovered. The remaining volatilized chlorides, chiefly those of iron and aluminum, are further treated to recover chlorine gas for recycle, and to recover ferric oxide and aluminum oxide as valuable by-products.

  14. Chlorination or monochloramination: Balancing the regulated trihalomethane formation and microbial inactivation in marine aquaculture waters

    KAUST Repository

    Sanawar, Huma

    2017-08-15

    Disinfection methods like chlorination are increasingly used to sanitize the water, equipment, tools and surfaces in aquaculture facilities. This is to improve water quality, and to maintain a hygienic environment for the well-being of aquatic organisms. However, chlorination can result in formation of regulated disinfection byproducts (DBPs) that can be carcinogenic and toxic. This study aims to evaluate if an optimal balance can be achieved between minimal regulated DBP formation and effective microbial inactivation with either chlorination or monochloramination for application in the Red Sea aquaculture waters. Upon chlorination, the concentration of total trihalomethanes (THMs), primarily bromoform, exceeded the regulatory limit of 80μg/L even at the lowest tested concentration of chlorine (1mg/L) and contact time (1h). Comparatively, regulated THMs concentration was only detectable at 30μg/L level in one of the three sets of monochloraminated marine aquaculture waters. The average log reduction of antibiotic-resistant bacteria (ARB) by chlorine ranged from 2.3-log to 3.2-log with different contact time. The average log reduction of ARB by monochloramine was comparatively lower at 1.9 to 2.9-log. Although viable Staphylococcus aureus was recovered from monochloraminated samples as opposed to chlorinated samples, the abundance of S. aureus was not high enough to result in any significant microbial risks. Both chlorination and monochloramination did not provide any significant improvement in the reduction of antibiotic resistance genes (ARGs). This study demonstrates that a systematic evaluation is needed to determine the optimal disinfectant required to balance both microbial and chemical risks. Compared to chlorine, monochloramine may be a more appropriate disinfection strategy for the treatment of aquaculture effluents prior to discharge or for recirculatory use in the aquaculture facility.

  15. 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.

  16. Ultraviolet light: sterile water without chlorine smell and taste

    International Nuclear Information System (INIS)

    Anon.

    1977-01-01

    The use of chlorine and hypochlorite is necessary in larger waterworks, but it is a disadvantage in smaller plants, where overtreatment easily leads to smell and taste of chlorine in the water. Ultraviolet light with a wavelength of 2535 Angstrom gives 100% disinfection with a dose of 10 mWs/cm 2 for all known bacteria. In practice a dose of 40 mWs/cm 2 and an irradiation time of 15 minutes is desireable. A standard unit utilising six UV light tubes arranged concentrically around a quartz tube, through which the water flows, is described briefly. (JIW)

  17. Ultraviolet light: sterile water without chlorine smell and taste

    Energy Technology Data Exchange (ETDEWEB)

    1977-02-14

    The use of chlorine and hypochlorite is necessary in larger waterworks, but it is a disadvantage in smaller plants, where overtreatment easily leads to smell and taste of chlorine in the water. Ultraviolet light with a wavelength of 2535 Angstrom gives 100% disinfection with a dose of 10 mWs/cm/sup 2/ for all known bacteria. In practice a dose of 40 mWs/cm/sup 2/ and an irradiation time of 15 minutes is desireable. A standard unit utilising six UV light tubes arranged concentrically around a quartz tube, through which the water flows, is described briefly.

  18. 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...

  19. Stratospheric chlorine injection by volcanic eruptions - HCl scavenging and implications for ozone

    Science.gov (United States)

    Tabazadeh, A.; Turco, R. P.

    1993-01-01

    Because the output of volatile chlorine during a major volcanic event can greatly exceed the annual anthropogenic emissions of chlorine to the atmosphere, the fate of volcanic chlorine must be known. Although numerous observations have shown that volcanoes do not significantly contribute to the stratospheric chlorine burden, no quantitative explanation has been published. Hydrogen chloride (HCl) scavenging processes during the early phases of a volcanic eruption are discussed. A plume dynamics and thermodynamics model is used to show that HCl removal in condensed supercooled water can reduce HCl vapor concentrations by up to four orders of magnitude, preventing substantial stratospheric chlorine injection.

  20. Determination of chlorine in nuclear-grade uranium compounds by ion-selective electrode

    International Nuclear Information System (INIS)

    Yang Chunqing; Liu Fuyun; Huang Dianfan.

    1989-01-01

    The determination of microamount chlorine in nuclear-grade uranium compounds is described. Chlorine is separated from uranium oxide pyrohydrolytically with stream of wet oxygen in a furnace at 800-900 deg C. Chlorine is volatilized as hydrochloric acid, which then is absorbed in a dilute alkaline solution and measured with chlorine selective electrode. This method covers the concentration range of 10-500 ppm chlorine in uranium oxide. The relative standard diviation is better than 10% and recovery of 85-108% has been reported

  1. 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

  2. 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.

  3. Epidemiological evidence of carcinogenicity of chlorinated organics in drinking water.

    OpenAIRE

    Cantor, K P

    1982-01-01

    Concern has recently been voiced over possible chronic toxicity associated with chlorination of public drinking water supplies in the United States. This paper reviews the available evidence and the studies underway to further evaluate hypothesized associations between cancer risk and byproducts of chlorination. Preliminary data from measures of halogenated volatiles and personal exposure histories from respondents in a large epidemiologic study of bladder cancer are presented. These data sup...

  4. Chlorine Decay and DBP formation under Different Flow Regions in PVC and Ductile Iron Pipes: Preliminary Results on the Role of flow Velocity and Radial Mass Transfer - Paper

    Science.gov (United States)

    A systematic experimental study was conducted using a pilot-scale drinking water distribution system simulator to quantify the effect of hydrodynamics, total organic carbon (TOC), initial disinfectant levels, and pipe materials on chlorine decay and disinfection by-product (DBP) ...

  5. Chlorine decay and DBP formation under different flow regions in PVC and ductile iron pipes: Preliminary results on the role of flow velocity and radial mass transfer

    Science.gov (United States)

    A systematic experimental study was conducted using a pilot-scale drinking water distribution system simulator to quantify the effect of hydrodynamics, total organic carbon (TOC), initial disinfectant levels, and pipe materials on chlorine decay and disinfection by-product (DBP) ...

  6. Impact of egg disinfection of hatching eggs on the eggshell microbiome and bacterial load

    DEFF Research Database (Denmark)

    Olsen, R.; Kudirkiene, E.; Thofner, I.

    2017-01-01

    Disinfection of hatching eggs is essential to ensure high quality production of broilers. Different protocols are followed in different hatcheries; however, only limited scientific evidence on how the disinfection procedures impact the microbiome is available. The aim of the present study...... was to characterize the microbiome and aerobic bacterial load of hatching eggs before disinfection and during the subsequent disinfection steps. The study included a group of visibly clean and a group of visibly dirty eggs. For dirty eggs, an initial wash in chlorine was performed, hereafter all eggs were submitted...... to two times fumigation and finally spray disinfection. The eggshell microbiome was characterized by sequencing of the total amount of 16S rRNA extracted from each sample, consisting of shell surface swabs of five eggs from the same group. In addition, the number of colony forming units (cfu) under...

  7. Destruction of disinfection byproducts and their precursors in swimming pool water by combined UV treatment and ozonation

    DEFF Research Database (Denmark)

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

    Both UV treatment and ozonation are used to reduce different types of disinfection byproducts (DBP) in swimming pools. UV treatment is most common as it is particularly efficient in removing the repulsive chlorine like smelling chloramines (combined chlorine). UV treatment of a pool water increased...... chlorine reactivity and formation of chlor-organic DBP such as trihalomethanes. Based on the similar selective reactivity of ozone and chlorine we hypothesized that the created reactivity towards chlorine by UV treatment of dissolved organic matter in pool water might also be expressed as an increased...... reactivity towards ozone and that ozonation might saturate the chlorine reactivity created by UV treatment and mitigate the increased DBP formation. By experimentally treating pool water samples, we found that UV treatment makes pool water highly reactive to ozone. The created reactivity towards chlorine...

  8. Technology assessment: Chlorine chemistry

    International Nuclear Information System (INIS)

    Wolff, H.; Alwast, H.; Buttgereit, R.

    1994-01-01

    Chlorine is not just one of many chemical feedstocks which is used in a few definitely harmful products like PVC or CFC but is irrelevant in all other respects. Just the opposite is true: There is hardly any product line of the chemical industry that can do without chlorine, from herbicides and pesticides to dyes, plastics, pharmaceuticals, photographic atricles, and cosmetics. Chlorine is not only a key element of chemical production but also an ubiquitous element of everyday life in civilisation. There are even many who would agree that the volume of chlorine production is an indicator of the competitive strength and national wealth of a modern society. By now, however, it has become evident that the unreflected use of chlorine is no longer ecologically acceptable. The consequences of a chlorine phase-out as compared to the continued chlorine production at the present level were investigated scientifically by a PROGNOS team. They are presented in this book. (orig.) [de

  9. 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.

  10. Thermodynamic consideration on chlorination of uraniferous phosphorite

    International Nuclear Information System (INIS)

    Itagaki, Kimio; Tozawa, Kazuteru; Taki, Tomihiro; Hirono, Shuichiro.

    1989-01-01

    The uranium ore of low grade which has apatite as a main mineral, but is different from the phosphorite used as the raw material for phosphoric acid production, exists in large amount in South America and Africa continents, and the importance of its effective utilization as future uranium resources is recognized. The Power Reactor and Nuclear Fuel Development Corp. took up the establishment of the treatment techniques to make this ore into resources as the subject of a project, and proposed the process of volatilizing the uranium in the ore as the chloride and recovering it, and at present, it attempts the experiment on the chlorination treatment. In this paper, the thermodynamic examination on the feasibility of this process, the optimum condition for leaving calcium existing in a large amount in the ore as the phosphate without chlorination and recovering only uranium by chlorination and volatilization, the phase reaction equilibrium chart and the calculation method according to thermodynamics concerning the behavior of chlorination of accompanying elements such as iron, silicon and aluminum and the effect of moisture in the ore are reported. (K.I.)

  11. NDMA Formation during Chlorination and Chloramination of Aqueous Diuron Solutions

    OpenAIRE

    Young, Thomas M

    2008-01-01

    Formation of the potent carcinogen N-nitrosodimethylamine (NDMA) during chlorine disinfection of water containing secondary amines is now generally acknowledged. The phenylurea herbicide diuron is one of the most widely used herbicides in California, has been frequently detected in California’s water sources with a transient nature of appearance, and has a structure that suggests it might be an NDMA precursor. This study sought to quantify the potential for NDMA formation from aqueous diuron ...

  12. Disinfection and regrowth potential of bacillus subtilis spores by ozone, ultraviolet rays and gamma irradiation

    International Nuclear Information System (INIS)

    Kim, Hae Yeon; Lee, O Mi; Kim, Tae Hun; Lee, Myun Joo; Yu, Seung Ho

    2009-01-01

    Chlorination has been the most commonly adopted disinfection process for the treatment of drinking water. However, Cryptosporidium parvum oocysts and Giardia lamblia cysts were not treated effectively by the common chlorine-based disinfectants. Additionally the regrowth of pathogenic microorganisms is associated with hygienic and aesthetic problems for the consumers of drinking water. Study on alternative disinfection processes such as ozone, UV-C, VUV and gamma irradiation were conducted. Bacillus subtilis spores have been used as a surrogate microorganism for Cryptosporidium parvum oocysts and Giardia lamblia cyst. Inactivation efficiency by ozone was from 30% to 96% within the range of 5 min to 120 min exposures. Inactivation efficiencies by UV-C and VUV were 95.18%, 95.07% at 30 sec, respectively. Inactivation efficiency at gamma irradiation dose of 2 kGy was 99.4%. Microbial regrowths after ozone, UV-C, VUV and gamma irradiation disinfections were also evaluated for 4 days. Bacillus subtilis spores after ozone treatment for 120 min exposure at the rate of 1.68 mg · min -1 showed 96.02% disinfection efficiency and significant microbial regrowth. Bacillus subtilis spores after UV-C (99.25% disinfection efficiency) and VUV (99.67% disinfection efficiency) treatments for 5 min showed gradual regrowth. However, inactivation efficiency of gamma irradiation at dose of 1 kGy was 98.8% and the disinfected sample showed no microbial regrowth for 4 days. Therefore, gamma irradiation is the most effective process for the disinfection of pathogenic microorganisms such as oocysts of protozoan parasites among four disinfection process

  13. Disinfection and regrowth potential of bacillus subtilis spores by ozone, ultraviolet rays and gamma irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hae Yeon; Lee, O Mi; Kim, Tae Hun; Lee, Myun Joo; Yu, Seung Ho [Korea Atomic Energy Research Institute, Jeongeup (Korea, Republic of)

    2009-06-15

    Chlorination has been the most commonly adopted disinfection process for the treatment of drinking water. However, Cryptosporidium parvum oocysts and Giardia lamblia cysts were not treated effectively by the common chlorine-based disinfectants. Additionally the regrowth of pathogenic microorganisms is associated with hygienic and aesthetic problems for the consumers of drinking water. Study on alternative disinfection processes such as ozone, UV-C, VUV and gamma irradiation were conducted. Bacillus subtilis spores have been used as a surrogate microorganism for Cryptosporidium parvum oocysts and Giardia lamblia cyst. Inactivation efficiency by ozone was from 30% to 96% within the range of 5 min to 120 min exposures. Inactivation efficiencies by UV-C and VUV were 95.18%, 95.07% at 30 sec, respectively. Inactivation efficiency at gamma irradiation dose of 2 kGy was 99.4%. Microbial regrowths after ozone, UV-C, VUV and gamma irradiation disinfections were also evaluated for 4 days. Bacillus subtilis spores after ozone treatment for 120 min exposure at the rate of 1.68 mg {center_dot} min{sup -1} showed 96.02% disinfection efficiency and significant microbial regrowth. Bacillus subtilis spores after UV-C (99.25% disinfection efficiency) and VUV (99.67% disinfection efficiency) treatments for 5 min showed gradual regrowth. However, inactivation efficiency of gamma irradiation at dose of 1 kGy was 98.8% and the disinfected sample showed no microbial regrowth for 4 days. Therefore, gamma irradiation is the most effective process for the disinfection of pathogenic microorganisms such as oocysts of protozoan parasites among four disinfection process.

  14. Disinfection of Ebola Virus in Sterilized Municipal Wastewater.

    Directory of Open Access Journals (Sweden)

    Kyle Bibby

    2017-02-01

    Full Text Available Concerns have been raised regarding handling of Ebola virus contaminated wastewater, as well as the adequacy of proposed disinfection approaches. In the current study, we investigate the inactivation of Ebola virus in sterilized domestic wastewater utilizing sodium hypochlorite addition and pH adjustment. No viral inactivation was observed in the one-hour tests without sodium hypochlorite addition or pH adjustment. No virus was recovered after 20 seconds (i.e. 4.2 log10 unit inactivation to detection limit following the addition of 5 and 10 mg L-1 sodium hypochlorite, which resulted in immediate free chlorine residuals of 0.52 and 1.11 mg L-1, respectively. The addition of 1 mg L-1 sodium hypochlorite resulted in an immediate free chlorine residual of 0.16 mg L-1, which inactivated 3.5 log10 units of Ebola virus in 20 seconds. Further inactivation was not evident due to the rapid consumption of the chlorine residual. Elevating the pH to 11.2 was found to significantly increase viral decay over ambient conditions. These results indicate the high susceptibility of the enveloped Ebola virus to disinfection in the presence of free chlorine in municipal wastewater; however, we caution that extension to more complex matrices (e.g. bodily fluids will require additional verification.

  15. Disinfection of Ebola Virus in Sterilized Municipal Wastewater.

    Science.gov (United States)

    Bibby, Kyle; Fischer, Robert J; Casson, Leonard W; de Carvalho, Nathalia Aquino; Haas, Charles N; Munster, Vincent J

    2017-02-01

    Concerns have been raised regarding handling of Ebola virus contaminated wastewater, as well as the adequacy of proposed disinfection approaches. In the current study, we investigate the inactivation of Ebola virus in sterilized domestic wastewater utilizing sodium hypochlorite addition and pH adjustment. No viral inactivation was observed in the one-hour tests without sodium hypochlorite addition or pH adjustment. No virus was recovered after 20 seconds (i.e. 4.2 log10 unit inactivation to detection limit) following the addition of 5 and 10 mg L-1 sodium hypochlorite, which resulted in immediate free chlorine residuals of 0.52 and 1.11 mg L-1, respectively. The addition of 1 mg L-1 sodium hypochlorite resulted in an immediate free chlorine residual of 0.16 mg L-1, which inactivated 3.5 log10 units of Ebola virus in 20 seconds. Further inactivation was not evident due to the rapid consumption of the chlorine residual. Elevating the pH to 11.2 was found to significantly increase viral decay over ambient conditions. These results indicate the high susceptibility of the enveloped Ebola virus to disinfection in the presence of free chlorine in municipal wastewater; however, we caution that extension to more complex matrices (e.g. bodily fluids) will require additional verification.

  16. 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.

  17. 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.

  18. Engineered Approaches to In Situ Bioremediation of Chlorinated Solvents: Fundamentals and Field Applications

    National Research Council Canada - National Science Library

    Fiedler, Linda

    2000-01-01

    Halogenated volatile organic compounds, including chlorinated solvents, are the most frequently-occurring type of soil and groundwater contaminant at Superfund and other hazardous waste sites in the United States. The U.S...

  19. Transformation of benzophenone-type UV filters by chlorine: Kinetics, products identification and toxicity assessments

    International Nuclear Information System (INIS)

    Li, Jian; Ma, Li-yun; Xu, Li

    2016-01-01

    Highlights: • Chlorination kinetics of three benzophenone-type UV filters (BPs) was studied. • Chlorination of BPs followed second-order reaction. • The transformation products (TPs) of six BPs were identified. • Several transformation pathways were proposed. • Mostly enhanced toxicity of TPs after chlorination was observed. - Abstract: The present study focused on the kinetics, transformation pathways and toxicity of several benzophenone-type ultraviolet filters (BPs) during the water chlorination disinfection process. The transformation kinetics of the studied three BPs was found to be second-order reaction, which was dependent on the concentration of BPs and chlorine. The second-order rate constants increased from 86.7 to 975 M"−"1 s"−"1 for oxybenzone, 49.6–261.7 M"−"1 s"−"1 for 4-hydroxybenzophenone and 51.7–540 M"−"1 s"−"1 for 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid with the increasing pH value from 6 to 8 of the chlorination disinfection condition. Then the transformation products (TPs) of these BPs were identified by HPLC-QTof analysis. Several transformation pathways, including electrophilic substitution, methoxyl substitution, ketone groups oxidation, hydrolysis, decarboxylation and ring cleavage reaction, were speculated to participate in the chlorination transformation process. Finally, according to the toxicity experiment on luminescent bacteria, Photobacterium phosphoreum, enhanced toxicity was observed for almost all the TPs of the studied BPs except for 2,2′-dihydroxy-4,4′-dimethoxybenzophenone; it suggested the formation of TPs with more toxic than the parent compounds during the chlorination process. The present study provided a foundation to understand the transformation of BPs during chlorination disinfection process, and was of great significance to the drinking water safety.

  20. Transformation of benzophenone-type UV filters by chlorine: Kinetics, products identification and toxicity assessments

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jian; Ma, Li-yun; Xu, Li, E-mail: xulpharm@mails.tjmu.edu.cn

    2016-07-05

    Highlights: • Chlorination kinetics of three benzophenone-type UV filters (BPs) was studied. • Chlorination of BPs followed second-order reaction. • The transformation products (TPs) of six BPs were identified. • Several transformation pathways were proposed. • Mostly enhanced toxicity of TPs after chlorination was observed. - Abstract: The present study focused on the kinetics, transformation pathways and toxicity of several benzophenone-type ultraviolet filters (BPs) during the water chlorination disinfection process. The transformation kinetics of the studied three BPs was found to be second-order reaction, which was dependent on the concentration of BPs and chlorine. The second-order rate constants increased from 86.7 to 975 M{sup −1} s{sup −1} for oxybenzone, 49.6–261.7 M{sup −1} s{sup −1} for 4-hydroxybenzophenone and 51.7–540 M{sup −1} s{sup −1} for 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid with the increasing pH value from 6 to 8 of the chlorination disinfection condition. Then the transformation products (TPs) of these BPs were identified by HPLC-QTof analysis. Several transformation pathways, including electrophilic substitution, methoxyl substitution, ketone groups oxidation, hydrolysis, decarboxylation and ring cleavage reaction, were speculated to participate in the chlorination transformation process. Finally, according to the toxicity experiment on luminescent bacteria, Photobacterium phosphoreum, enhanced toxicity was observed for almost all the TPs of the studied BPs except for 2,2′-dihydroxy-4,4′-dimethoxybenzophenone; it suggested the formation of TPs with more toxic than the parent compounds during the chlorination process. The present study provided a foundation to understand the transformation of BPs during chlorination disinfection process, and was of great significance to the drinking water safety.

  1. 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

  2. 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.

  3. Peracetic acid: the long road to introduction of this disinfectant into U.S. aquaculture

    Science.gov (United States)

    Peracetic acid (PAA) is a promising disinfectant for biosecurity in the US aquaculture industry to prevent disease outbreaks from fish pathogens. PAA is a stabilized mixture of acetic acid, hydrogen peroxide and water that breaks down quickly to water and vinegar. It has replaced chlorine in some ...

  4. 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.

  5. 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)

  6. Occurrence of disinfection byproducts in United States wastewater treatment plant effluents

    KAUST Repository

    Krasner, Stuart W.

    2009-11-01

    Effluents from wastewater treatment plants (WWTPs) contain disinfection byproducts (DBPs) of health concern when the water is utilized downstream as a potable water supply. The pattern of DBP formation was strongly affected by whether or not the WWTP achieved good nitrification. Chlorine addition to poorly nitrified effluents formed low levels of halogenated DBPs, except for (in some cases) dihalogenated acetic acids, but often substantial amounts of N-nitrosodimethyamine (NDMA). Chlorination of well-nitrified effluent typically resulted in substantial formation of halogenated DBPs but much less NDMA. For example, on a median basis after chlorine addition, the well-nitrified effluents had 57 μg/L of trihalomethanes [THMs] and 3 ng/L of NDMA, while the poorly nitrified effluents had 2 μg/L of THMs and 11 ng/L of NDMA. DBPs with amino acid precursors (haloacetonitriles, haloacetaldehydes) formed at substantial levels after chlorination of well-nitrified effluent. The formation of halogenated DBPs but not that of NDMA correlated with the formation of THMs in WWTP effluents disinfected with free chlorine. However, THM formation did not correlate with the formation of other DBPs in effluents disinfected with chloramines. Because of the relatively high levels of bromide in treated wastewater, bromine incorporation was observed in various classes of DBPs. © 2009 American Chemical Society.

  7. Occurrence of disinfection byproducts in United States wastewater treatment plant effluents

    KAUST Repository

    Krasner, Stuart W.; Westerhoff, Paul K.; Chen, Baiyang; Rittmann, Bruce E.; Amy, Gary L.

    2009-01-01

    Effluents from wastewater treatment plants (WWTPs) contain disinfection byproducts (DBPs) of health concern when the water is utilized downstream as a potable water supply. The pattern of DBP formation was strongly affected by whether or not the WWTP achieved good nitrification. Chlorine addition to poorly nitrified effluents formed low levels of halogenated DBPs, except for (in some cases) dihalogenated acetic acids, but often substantial amounts of N-nitrosodimethyamine (NDMA). Chlorination of well-nitrified effluent typically resulted in substantial formation of halogenated DBPs but much less NDMA. For example, on a median basis after chlorine addition, the well-nitrified effluents had 57 μg/L of trihalomethanes [THMs] and 3 ng/L of NDMA, while the poorly nitrified effluents had 2 μg/L of THMs and 11 ng/L of NDMA. DBPs with amino acid precursors (haloacetonitriles, haloacetaldehydes) formed at substantial levels after chlorination of well-nitrified effluent. The formation of halogenated DBPs but not that of NDMA correlated with the formation of THMs in WWTP effluents disinfected with free chlorine. However, THM formation did not correlate with the formation of other DBPs in effluents disinfected with chloramines. Because of the relatively high levels of bromide in treated wastewater, bromine incorporation was observed in various classes of DBPs. © 2009 American Chemical Society.

  8. Effect of Different Disinfection Protocols on Microbial and Biofilm Contamination of Dental Unit Waterlines in Community Dental Practices

    Directory of Open Access Journals (Sweden)

    Laura Dallolio

    2014-02-01

    Full Text Available Output water from dental unit waterlines (DUWLs may be a potential source of infection for both dental healthcare staff and patients. This study compared the efficacy of different disinfection methods with regard to the water quality and the presence of biofilm in DUWLs. Five dental units operating in a public dental health care setting were selected. The control dental unit had no disinfection system; two were disinfected intermittently with peracetic acid/hydrogen peroxide 0.26% and two underwent continuous disinfection with hydrogen peroxide/silver ions (0.02% and stabilized chlorine dioxide (0.22%, respectively. After three months of applying the disinfection protocols, continuous disinfection systems were more effective than intermittent systems in reducing the microbial contamination of the water, allowing compliance with the CDC guidelines and the European Council regulatory thresholds for drinking water. P. aeruginosa, Legionella spp, sulphite-reducing Clostridium spores, S. aureus and β-haemolytic streptococci were also absent from units treated with continuous disinfection. The biofilm covering the DUWLs was more extensive, thicker and more friable in the intermittent disinfection dental units than in those with continuous disinfection. Overall, the findings showed that the products used for continuous disinfection of dental unit waterlines showed statistically better results than the intermittent treatment products under the study conditions.

  9. Effect of different disinfection protocols on microbial and biofilm contamination of dental unit waterlines in community dental practices.

    Science.gov (United States)

    Dallolio, Laura; Scuderi, Amalia; Rini, Maria S; Valente, Sabrina; Farruggia, Patrizia; Sabattini, Maria A Bucci; Pasquinelli, Gianandrea; Acacci, Anna; Roncarati, Greta; Leoni, Erica

    2014-02-18

    Output water from dental unit waterlines (DUWLs) may be a potential source of infection for both dental healthcare staff and patients. This study compared the efficacy of different disinfection methods with regard to the water quality and the presence of biofilm in DUWLs. Five dental units operating in a public dental health care setting were selected. The control dental unit had no disinfection system; two were disinfected intermittently with peracetic acid/hydrogen peroxide 0.26% and two underwent continuous disinfection with hydrogen peroxide/silver ions (0.02%) and stabilized chlorine dioxide (0.22%), respectively. After three months of applying the disinfection protocols, continuous disinfection systems were more effective than intermittent systems in reducing the microbial contamination of the water, allowing compliance with the CDC guidelines and the European Council regulatory thresholds for drinking water. P. aeruginosa, Legionella spp, sulphite-reducing Clostridium spores, S. aureus and β-haemolytic streptococci were also absent from units treated with continuous disinfection. The biofilm covering the DUWLs was more extensive, thicker and more friable in the intermittent disinfection dental units than in those with continuous disinfection. Overall, the findings showed that the products used for continuous disinfection of dental unit waterlines showed statistically better results than the intermittent treatment products under the study conditions.

  10. Influences of packaging design on antimicrobial effects of gaseous chlorine dioxide

    Science.gov (United States)

    Chlorine dioxide (ClO2) gas is an effective surface disinfectant, for it has the ability to reach and inactivate bacterial cells in biofilms which are attached to inaccessible sites on produce surfaces. One of the most promising applications of gaseous ClO2 is to be included in the headspace of foo...

  11. Degradation of Organic UV filters in Chlorinated Seawater Swimming Pools: Transformation Pathways and Bromoform Formation.

    Science.gov (United States)

    Manasfi, Tarek; Coulomb, Bruno; Ravier, Sylvain; Boudenne, Jean-Luc

    2017-12-05

    Organic ultraviolet (UV) filters are used in sunscreens and other personal-care products to protect against harmful effects of exposure to UV solar radiation. Little is known about the fate of UV filters in seawater swimming pools disinfected with chlorine. The present study investigated the occurrence and fate of five commonly used organic UV filters, namely dioxybenzone, oxybenzone, avobenzone, 2-ethylhexyl-4-methoxycinnamate, and octocrylene, in chlorinated seawater swimming pools. Pool samples were collected to monitor the variation of UV filter concentrations during pool opening hours. Furthermore, laboratory-controlled chlorination experiments were conducted in seawater spiked with UV filters to investigate the reactivity of UV filters. Extracts of chlorination reaction samples were analyzed using high-resolution mass spectrometry and electron-capture detection to identify the potentially formed byproducts. In the collected pool samples, all the UV filters except dioxybenzone were detected. Chlorination reactions showed that only octocrylene was stable in chlorinated seawater. The four reactive UV filters generated brominated transformation products and disinfection byproducts. This formation of brominated products resulted from reactions between the reactive UV filters and bromine, which is formed rapidly when chlorine is added to seawater. Based on the identified byproducts, the transformation pathways of the reactive UV filters were proposed for the first time. Bromoform was generated by all the reactive UV filters at different yields. Bromal hydrate was also detected as one of the byproducts generated by oxybenzone and dioxybenzone.

  12. Health effects from swimming training in chlorinated pools and the corresponding metabolic stress pathways.

    Directory of Open Access Journals (Sweden)

    Jiang-Hua Li

    Full Text Available Chlorination is the most popular method for disinfecting swimming pool water; however, although pathogens are being killed, many toxic compounds, called disinfection by-products (DBPs, are formed. Numerous epidemiological publications have associated the chlorination of pools with dysfunctions of the respiratory system and with some other diseases. However, the findings concerning these associations are not always consistent and have not been confirmed by toxicological studies. Therefore, the health effects from swimming in chlorinated pools and the corresponding stress reactions in organisms are unclear. In this study, we show that although the growth and behaviors of experimental rats were not affected, their health, training effects and metabolic profiles were significantly affected by a 12-week swimming training program in chlorinated water identical to that of public pools. Interestingly, the eyes and skin are the organs that are more directly affected than the lungs by the irritants in chlorinated water; instead of chlorination, training intensity, training frequency and choking on water may be the primary factors for lung damage induced by swimming. Among the five major organs (the heart, liver, spleen, lungs and kidneys, the liver is the most likely target of DBPs. Through metabolomics analysis, the corresponding metabolic stress pathways and a defensive system focusing on taurine were presented, based on which the corresponding countermeasures can be developed for swimming athletes and for others who spend a lot of time in chlorinated swimming pools.

  13. Identification of reaction products from reactions of free chlorine with the lipid-regulator gemfibrozil.

    Science.gov (United States)

    Krkošek, Wendy H; Koziar, Stephen A; White, Robert L; Gagnon, Graham A

    2011-01-01

    High global consumption rates have led to the occurrence of pharmaceutically active compounds (PhACs) in wastewater. The use of chlorine to disinfect wastewater prior to release into the environment may convert PhACs into uncharacterized chlorinated by-products. In this investigation, chlorination of a common pharmaceutical, the antihyperlipidemic agent gemfibrozil, was documented. Gemfibrozil (2,2-dimethyl-5-(2,5-dimethylphenoxy)pentanoic acid) was reacted with sodium hypochlorite and product formation was monitored by gas chromatography-mass spectrometry (GC-MS). The incorporation of one, two or three chlorine atoms into the aromatic region of gemfibrozil was demonstrated using negative-ion electrospray ionization mass spectrometry (ESI-MS) and tandem mass spectrometry (ESI-MS/MS). Further analysis using (1)H nuclear magnetic resonance (NMR) spectroscopy identified the reaction products as 4'-ClGem (5-(4-chloro-2,5-dimethylphenoxy)-2,2-dimethylpentanoic acid) 4',6'-diClGem (5-(4,6-dichloro-2,5-dimethylphenoxy)-2,2-dimethylpentanoic acid), and 3',4',6'-triClGem (5-(3,4,6-trichloro-2,5-dimethylphenoxy)-2,2-dimethylpentanoic acid), products consistent with electrophilic aromatic substitution reactions. The rapid reaction of gemfibrozil with free chlorine at pH conditions relevant to water treatment indicates that a mixture of chlorinated gemfibrozils is likely to be found in wastewater disinfected with chlorine. Copyright © 2010 Elsevier Ltd. All rights reserved.

  14. Evaluation of 5 cleaning and disinfection methods for nets used to collect zebrafish (Danio rerio).

    Science.gov (United States)

    Collymore, Chereen; Porelli, Gina; Lieggi, Christine; Lipman, Neil S

    2014-11-01

    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 peroxymonosulfate+sodium chloride for a soak time of 5 or 30 min. Disinfection effectiveness was evaluated by using an ATP-based system that measured the reduction in absolute number and percentage of relative light units. In addition, nets were cultured aerobically on blood and MacConkey agar plates to determine the number of bacteria remaining after disinfection procedures. Soaking nets in sodium hypochlorite for 30 min and in potassium peroxymonosulfate+sodium chloride for 5 or 30 min were effective means of disinfection, according to at least 90% reduction in the number of relative light units and no bacterial growth after cleaning. These results will aid facility managers, veterinarians and investigators in selecting net cleaning and disinfection protocols.

  15. Effect of Disinfectants on Preventing the Cross-Contamination of Pathogens in Fresh Produce Washing Water

    Science.gov (United States)

    Banach, Jennifer L.; Sampers, Imca; Van Haute, Sam; van der Fels-Klerx, H.J. (Ine)

    2015-01-01

    The potential cross-contamination of pathogens between clean and contaminated produce in the washing tank is highly dependent on the water quality. Process wash water disinfectants are applied to maintain the water quality during processing. The review examines the efficacy of process wash water disinfectants during produce processing with the aim to prevent cross-contamination of pathogens. Process wash water disinfection requires short contact times so microorganisms are rapidly inactivated. Free chlorine, chlorine dioxide, ozone, and peracetic acid were considered suitable disinfectants. A disinfectant’s reactivity with the organic matter will determine the disinfectant residual, which is of paramount importance for microbial inactivation and should be monitored in situ. Furthermore, the chemical and worker safety, and the legislative framework will determine the suitability of a disinfection technique. Current research often focuses on produce decontamination and to a lesser extent on preventing cross-contamination. Further research on a sanitizer’s efficacy in the washing water is recommended at the laboratory scale, in particular with experimental designs reflecting industrial conditions. Validation on the industrial scale is warranted to better understand the overall effects of a sanitizer. PMID:26213953

  16. Effect of Disinfectants on Preventing the Cross-Contamination of Pathogens in Fresh Produce Washing Water

    Directory of Open Access Journals (Sweden)

    Jennifer L. Banach

    2015-07-01

    Full Text Available The potential cross-contamination of pathogens between clean and contaminated produce in the washing tank is highly dependent on the water quality. Process wash water disinfectants are applied to maintain the water quality during processing. The review examines the efficacy of process wash water disinfectants during produce processing with the aim to prevent cross-contamination of pathogens. Process wash water disinfection requires short contact times so microorganisms are rapidly inactivated. Free chlorine, chlorine dioxide, ozone, and peracetic acid were considered suitable disinfectants. A disinfectant’s reactivity with the organic matter will determine the disinfectant residual, which is of paramount importance for microbial inactivation and should be monitored in situ. Furthermore, the chemical and worker safety, and the legislative framework will determine the suitability of a disinfection technique. Current research often focuses on produce decontamination and to a lesser extent on preventing cross-contamination. Further research on a sanitizer’s efficacy in the washing water is recommended at the laboratory scale, in particular with experimental designs reflecting industrial conditions. Validation on the industrial scale is warranted to better understand the overall effects of a sanitizer.

  17. Chlorine solar neutrino experiment

    International Nuclear Information System (INIS)

    Rowley, J.K.; Cleveland, B.T.; Davis, R. Jr.

    1984-01-01

    The chlorine solar neutrino experiment in the Homestake Gold Mine is described and the results obtained with the chlorine detector over the last fourteen years are summarized and discussed. Background processes producing 37 Ar and the question of the constancy of the production rate of 37 Ar are given special emphasis

  18. 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.

  19. 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.

  20. Influence of drinking water treatments on chlorine dioxide consumption and chlorite/chlorate formation.

    Science.gov (United States)

    Sorlini, Sabrina; Gialdini, Francesca; Biasibetti, Michela; Collivignarelli, Carlo

    2014-05-01

    Disinfection is the last treatment stage of a Drinking Water Treatment Plant (DWTP) and is carried out to maintain a residual concentration of disinfectant in the water distribution system. Chlorine dioxide (ClO2) is a widely used chemical employed for this purpose. The aim of this work was to evaluate the influence of several treatments on chlorine dioxide consumption and on chlorite and chlorate formation in the final oxidation/disinfection stage. A number of tests was performed at laboratory scale employing water samples collected from the DWTP of Cremona (Italy). The following processes were studied: oxidation with potassium permanganate, chlorine dioxide and sodium hypochlorite, coagulation/flocculation with ferric chloride and aluminum sulfate, filtration and adsorption onto activated carbon. The results showed that the chlorine dioxide demand is high if sodium hypochlorite or potassium permanganate are employed in pre-oxidation. On the other hand, chlorine dioxide leads to the highest production of chlorite and chlorate. The coagulation/flocculation process after pre-oxidation shows that chlorine dioxide demand decreases if potassium permanganate is employed as an oxidant, both with ferric chloride and aluminum sulfate. Therefore, the combination of these processes leads to a lower production of chlorite and chlorate. Aluminum sulfate is preferable in terms of the chlorine dioxide demand reduction and minimization of the chlorite and chlorate formation. Activated carbon is the most effective solution as it reduced the chlorine dioxide consumption by about 50% and the DBP formation by about 20-40%. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Effects of assimilable organic carbon and free chlorine on bacterial growth in drinking water.

    Directory of Open Access Journals (Sweden)

    Xiaolu Liu

    Full Text Available Assimilable organic carbon (AOC is one of the most important factors affecting the re-growth of microorganisms in drinking water. High AOC concentrations result in biological instability, but disinfection kills microbes to ensure the safety of drinking water. Free chlorine is an important oxidizing agent used during the disinfection process. Therefore, we explored the combined effects of AOC and free chlorine on bacterial growth in drinking water using flow cytometry (FCM. The initial AOC concentration was 168 μg.L(-1 in all water samples. Without free chlorine, the concentrations of intact bacteria increased but the level of AOC decreased. The addition of sodium hypochlorite caused an increase and fluctuation in AOC due to the oxidation of organic carbon. The concentrations of intact bacteria decreased from 1.1 × 10(5 cells.mL(-1 to 2.6 × 10(4 cells.mL(-1 at an initial free chlorine dose of 0.6 mg.L(-1 to 4.8 × 10(4 cells.mL(-1 at an initial free chlorine dose of 0.3 mg.L(-1 due to free chlorine originating from sodium hypochlorite. Additionally, free chlorine might be more obviously affected AOC concentrations than microbial growth did. These results suggested that AOC and free chlorine might have combined effects on microbial growth. In this study, our results showed concentrations determined by FCM were higher than those by HPC, which indicated that some E. coli detected by FCM might not be detected using HPC in drinking water. The level of free chlorine might restrain the consumption of AOC by inhibiting the growth of E. coli; on the other hand, chlorination might increase the level of AOC, thereby increase the potential for microbial growth in the drinking water network.

  2. Volatility Discovery

    DEFF Research Database (Denmark)

    Dias, Gustavo Fruet; Scherrer, Cristina; Papailias, Fotis

    The price discovery literature investigates how homogenous securities traded on different markets incorporate information into prices. We take this literature one step further and investigate how these markets contribute to stochastic volatility (volatility discovery). We formally show...... that the realized measures from homogenous securities share a fractional stochastic trend, which is a combination of the price and volatility discovery measures. Furthermore, we show that volatility discovery is associated with the way that market participants process information arrival (market sensitivity......). Finally, we compute volatility discovery for 30 actively traded stocks in the U.S. and report that Nyse and Arca dominate Nasdaq....

  3. 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.

  4. 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.

  5. Formation of trihalomethanes as disinfection byproducts in herbal spa pools.

    Science.gov (United States)

    Fakour, Hoda; Lo, Shang-Lien

    2018-04-09

    Herbal spa treatments are favorite recreational activities throughout the world. The water in spas is often disinfected to control pathogenic microorganisms and guarantee hygiene. However, chlorinated water may cause the formation of disinfection byproducts (DBPs). Although there have been many studies on DBP formation in swimming pools, the role of organic matter derived from herbal medicines applied in herbal spa water has been largely neglected. Accordingly, the present study investigated the effect of herbal medicines on the formation of trihalomethanes (THMs) in simulated herbal spa water. Water samples were collected from a spa pool, and then, disinfection and herbal addition experiments were performed in a laboratory. The results showed that the organic molecules introduced by the herbal medicines are significant precursors to the formation of THMs in spa pool water. Since at least 50% of THMs were produced within the first six hours of the reaction time, the presence of herbal medicines in spa water could present a parallel route for THM exposure. Therefore, despite the undeniable benefits of herbal spas, the effect of applied herbs on DBP formation in chlorinated water should be considered to improve the water quality and health benefits of spa facilities.

  6. Chloride pyrometallurgy of uranium ore. 1. Chlorination of phosphate ore using solid or gas chlorinating agent and carbon

    International Nuclear Information System (INIS)

    Taki, Tomihiro; Komoto, Shigetoshi; Otomura, Keiichiro; Takenaka, Toshihide; Sato, Nobuaki; Fujino, Takeo.

    1995-01-01

    A thermodynamical and pyrometallurgical study to recover uranium from the phosphate ores was undertaken using the chloride volatilization method. Iron was chlorinated with solid chlorinating agents such as NaCl and CaCl 2 in combination with activated carbon, which will be used for removing this element from the ore, but uranium was not. On the other hand, the chlorination using Cl 2 gas and activated carbon gave a good result at 1,223 K. Not only uranium but also iron, phosphorus, aluminum and silicon were found to form volatile chlorides which vaporized out of the ore, while calcium remained in the ore as non-volatile CaCl 2 . The chlorination condition was studied as functions of temperature, reaction time and carbon content. The volatilization ratio of uranium around 95% was obtained by heating the mixture of the ore and activated carbon (35 wt%) in a mixed gas flow of Cl 2 (200 ml/min) and N 2 (200 ml/min) at 1,223 K for 120 min. (author)

  7. Characterization of a stirred tank electrochemical cell for water disinfection processes

    International Nuclear Information System (INIS)

    Polcaro, A.M.; Vacca, A.; Mascia, M.; Palmas, S.; Pompei, R.; Laconi, S.

    2007-01-01

    Laboratory experiments were performed to characterize the behaviour of an electrochemical cell equipped with boron-doped diamond anodes and to verify its effectiveness in water disinfection. The hydrodynamic regime was determined when the cell worked either in batch or in continuous mode. Galvanostatic electrolyses of aqueous 1 mM Na 2 SO 4 solutions were performed to investigate on the oxidant production in different experimental conditions. The same solutions contaminated by E. coli, enterococci and coliforms were used as test media to verify the effectiveness of the system in the disinfection process. Experimental results indicated that the major inactivation mechanism of bacteria in the electrochemical cell is a disinfection by electrochemically generated oxidants, however a cooperative effect of superficial reaction has to be taken into account. The great capability of BDD anode to produce reactive oxygen species (ROS) and other oxidizing species during the electrolysis allows to establish a chlorine-free disinfection process

  8. 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.

  9. 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)

  10. Immobilization of chlorine dioxide modified cells for uranium absorption

    International Nuclear Information System (INIS)

    He, Shengbin; Ruan, Binbiao; Zheng, Yueping; Zhou, Xiaobin; Xu, Xiaoping

    2014-01-01

    There has been a trend towards the use of microorganisms to recover metals from industrial wastewater, for which various methods have been reported to be used to improve microorganism adsorption characteristics such as absorption capacity, tolerance and reusability. In present study, chlorine dioxide(ClO 2 ), a high-efficiency, low toxicity and environment-benign disinfectant, was first reported to be used for microorganism surface modification. The chlorine dioxide modified cells demonstrated a 10.1% higher uranium adsorption capacity than control ones. FTIR analysis indicated that several cell surface groups are involved in the uranium adsorption and cell surface modification. The modified cells were further immobilized on a carboxymethylcellulose (CMC) matrix to improve their reusability. The cell-immobilized adsorbent could be employed either in a high concentration system to move vast UO 2 2+ ions or in a low concentration system to purify UO 2 2+ contaminated water thoroughly, and could be repeatedly used in multiple adsorption-desorption cycles with about 90% adsorption capacity maintained after seven cycles. - Highlights: • Chlorine dioxide was first reported to be used for microorganism surface modification. • The chlorine dioxide modified cells demonstrated a 10.1% higher uranium adsorption capacity than control ones. • The chlorine dioxide modified cells were further immobilized by carboxymethylcellulose to improve their reusability

  11. 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

  12. Virtual volatility

    Science.gov (United States)

    Silva, A. Christian; Prange, Richard E.

    2007-03-01

    We introduce the concept of virtual volatility. This simple but new measure shows how to quantify the uncertainty in the forecast of the drift component of a random walk. The virtual volatility also is a useful tool in understanding the stochastic process for a given portfolio. In particular, and as an example, we were able to identify mean reversion effect in our portfolio. Finally, we briefly discuss the potential practical effect of the virtual volatility on an investor asset allocation strategy.

  13. 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.

  14. Zirconia concentrate chlorination

    International Nuclear Information System (INIS)

    Costa, N.G.; Albuquerque Brocchi, E. de

    1990-01-01

    Chlorination experiments were conducted in order to study the kinetics of gasification of the zirconium oxide present in the zirconia concentrate. The variables studied are temperature (1173 to 1373 K), percentage of reducing agent (12 to 36%) and porosity (22 to 30%). The results indicated a greater influence of temperature and percentage of reducing agent as well as allowed the conclusion that a balance between the levels of these variables is an important factor in the appropriate chlorination conditions. (author)

  15. Chlorine trifluoride (1963)

    International Nuclear Information System (INIS)

    Vincent, L.M.; Gillardeau, J.

    1963-01-01

    This monograph on chlorine trifluoride may be considered as a working tool useful in gaseous diffusion research. It consists of data gathered from the literature and includes furthermore a certain amount of original data. This monograph groups together the physical, chemical and physiological properties of chlorine trifluoride, as well as the preparation and analytical methods. It has been thought wise to add some technological information, and the safety regulations governing its use. (authors) [fr

  16. Iodine volatility

    International Nuclear Information System (INIS)

    Beahm, E.C.; Shockley, W.E.

    1984-01-01

    The ultimate aim of this program is to couple experimental aqueous iodine volatilities to a fission product release model. Iodine partition coefficients, for inorganic iodine, have been measured during hydrolysis and radiolysis. The hydrolysis experiments have illustrated the importance of reaction time on iodine volatility. However, radiolysis effects can override hydrolysis in determining iodine volatility. In addition, silver metal in radiolysis samples can react to form silver iodide accompanied by a decrease in iodine volatility. Experimental data are now being coupled to an iodine transport and release model that was developed in the Federal Republic of Germany

  17. Disinfection of treated sewage. [Ultra-violet irradiation

    Energy Technology Data Exchange (ETDEWEB)

    From, J O

    1976-09-02

    The release of treated sewage in the vicinity of bathing places, drinking water sources or fish and shellfish culture plants is undesirable due to high bacterial content. Disinfection by chlorine would be relatively expensive and the toxicity would result in a local dead zone. The formation of small, but measurable, amounts of persistent chlorated hydrocarbons could also lead to long-term biological effects. Disinfection by ozone or gamma radiation would involve investments unacceptable in small plants. Ultraviolet radiation with wavelength 2500-2600 A has a powerful bacteriocidal effect and has been demonstrated to give bacterial mortality of 99.96 to 99.997 %. A standard plant produced in USA with a capacity of 11.3 m/sup 3//h is illustrated. UV radiation has no effect on the chemical composition of the water and the operating costs are low.

  18. Reduction of tri halomethanes in drinking water using chlorine dioxide as a pre oxidant; Rduccion de trihalometanos en agua potable mediante preoxidacion con dioxido de cloro

    Energy Technology Data Exchange (ETDEWEB)

    Marcian Cervera, V. J.; Monforte Monleon, L.; Ribera Orts, R.; Alvarez Alondiga, I.; Garcia Garrido, J.

    2007-07-01

    The object of the present study is to verify the suitability of using chlorine dioxide as a pre oxidant in the Water Treatment Plant of La Presa (Manises) and El Realon (Picassent), in order to minimize the tri halomethanes formation. To prove the effectiveness of chlorine dioxide, on the tri halomethanes precursors removal by oxidation, many controls and analytics have been done on the two water treatment plants. On the other hand this study also shows the chlorine dioxide generation method used, as well as its high disinfection efficiency, higher than the chlorine. (Author)

  19. Inactivation of Mycobacterium avium with free chlorine.

    Science.gov (United States)

    Luh, Jeanne; Mariñas, Benito J

    2007-07-15

    The inactivation kinetics of Mycobacterium avium with free chlorine was characterized by two stages: an initial phase at a relatively fast rate followed by a slower second stage of pseudo first-order kinetics. The inactivation rate of each stage was approximately the same for all experiments performed at a certain condition of pH and temperature; however, variability was observed for the disinfectant exposure at which the transition between the two stages occurred. This variability was not a function of the initial disinfectant concentration, the initial bacterial density, or the bacterial stock. However, the transition to the second stage varied more significantly at high temperatures (30 degrees C), while lower variability was observed at lower temperatures (5 and 20 degrees C). Experiments conducted at pH values in the range of 6-9 revealed that the inactivation of M. avium was primarily due to hypochlorous acid, with little contribution from hypochlorite ion within this pH range. The inactivation kinetics was represented with a two-population model. The activation energies for the resulting pseudo first-order rate constants for the populations with fast and slow kinetics were 100.3 and 96.5 kJ/mol, respectively. The magnitude of these values suggested that for waters of relatively high pH and low temperatures, little inactivation of M. avium would be achieved within treatment plants, providing a seeding source for distribution systems.

  20. 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

  1. 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

  2. A carbon nanotube based resettable sensor for measuring free chlorine in drinking water

    International Nuclear Information System (INIS)

    Hsu, Leo H. H.; Hoque, Enamul; Kruse, Peter; Ravi Selvaganapathy, P.

    2015-01-01

    Free chlorine from dissolved chlorine gas is widely used as a disinfectant for drinking water. The residual chlorine concentration has to be continuously monitored and accurately controlled in a certain range around 0.5–2 mg/l to ensure drinking water safety and quality. However, simple, reliable, and reagent free monitoring devices are currently not available. Here, we present a free chlorine sensor that uses oxidation of a phenyl-capped aniline tetramer (PCAT) to dope single wall carbon nanotubes (SWCNTs) and to change their resistance. The oxidation of PCAT by chlorine switches the PCAT-SWCNT system into a low resistance (p-doped) state which can be detected by probing it with a small voltage. The change in resistance is found to be proportional to the log-scale concentration of the free chlorine in the sample. The p-doping of the PCAT-SWCNT film then can be electrochemically reversed by polarizing it cathodically. This sensor not only shows good sensing response in the whole concentration range of free chlorine in drinking water but is also able to be electrochemically reset back many times without the use of any reagents. This simple sensor is ideally suited for measuring free chlorine in drinking water continuously

  3. 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...

  4. Effect of Changing Treatment Disinfectants on the Microbiology of Distributed Water and Pipe Biofilm Communities using Conventional and Metagenomic Approaches

    Science.gov (United States)

    The purpose of this research was to add to our knowledge of chlorine and monochloramine disinfectants, with regards to effects on the microbial communities in distribution systems. A whole metagenome-based approach using sophisticated molecular tools (e.g., next generation sequen...

  5. Factors affecting THMs, HAAs and HNMs formation of Jin Lan Reservoir water exposed to chlorine and monochloramine.

    Science.gov (United States)

    Hong, Huachang; Xiong, Yujing; Ruan, Mengyong; Liao, Fanglei; Lin, Hongjun; Liang, Yan

    2013-02-01

    The formations of THMs, HAAs, and HNMs from chlorination and chloramination of water from Jinlan Reservoir were investigated in this study. Results showed that monochloramine rather than chlorine generally resulted in lower concentration of DBPs, and the DBPs formation varied greatly as the treatment conditions changed. Specifically, the yields of THMs, HAAs and HNMs all increased with the high bromide level and high disinfectant dose both during chlorination and chloramination. The longer reaction time had a positive effect on the formation of THMs, HAAs and HNMs during chlorination and HNMs during chloramination. However, no time effect was observed on the formation of THMs and HAAs during chloramination. An increase in pH enhanced the levels of THMs and HNMs upon chlorination but reduced levels of HNMs upon chloramination. As for the THMs in chloramination and HAAs in chlorination and chloramination, no obvious pH effect was observed. The elevated temperature significantly increased the yields of THMs during chlorination and HNMs during chloramination, but has no effect on THMs and HAAs yields during chloramination. In the same temperature range, the formation of HAAs and HNMs in chlorination showed a first increasing and then a decreasing trend. In chloramination study, addition of nitrite markedly increased the formation of HNMs but had little impact on the formation of THMs and HAAs. While in chlorination study, the presence of high nitrite levels significantly reduced the yields of THMs, HAAs and HNMs. Range analysis revealed that the bromide and disinfectant levels were the major factors affecting THMs, HAAs and HNMs formation, in both chlorination and chloramination. Finally, comparisons of the speciation of mono-halogenated, di-halogenated, tri-halogenated HAAs and HNMs between chlorination and monochloramination were also conducted, and factors influencing the speciation pattern were identified. Copyright © 2012 Elsevier B.V. All rights reserved.

  6. UV drinking water disinfection with photovoltaic power supply. UV-Trinkwasserentkeimung mit photovoltaischer Stromversorgung

    Energy Technology Data Exchange (ETDEWEB)

    Scharmer, K; Pappers, B; Guenner, C

    1990-06-01

    The study carried out on commission of the BMFT describes in the first three chapters UV disinfectation systems as well as experience gained from their use in industry and developing countries. In the chapter 4-7 special requirements for the use in developing countries are specified and compared to the results of other projects of the BMFT, GTZ and UNIDO. Chapter 5 gives a matrix of cost in which UV and chlorine disinfectation are compared to each other. In the final chapters 8 and 9 test programs and laboratory tests are described which are to serve as basis for planned field tests. (ORU).

  7. 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

  8. 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

  9. Effects of electrolysis time and electric potential on chlorine generation of electrolyzed deep ocean water

    Directory of Open Access Journals (Sweden)

    Guoo-Shyng Wang Hsu

    2017-10-01

    Full Text Available Electrolyzed water is a sustainable disinfectant, which can comply with food safety regulations and is environmentally friendly. A two-factor central composite design was adopted for studying the effects of electrolysis time and electric potential on the chlorine generation efficiency of electrolyzed deep ocean water (DOW. DOW was electrolyzed in a glass electrolyzing cell equipped with platinum–plated titanium anode and cathode. The results showed that chlorine concentration reached maximal level in the batch process. Prolonged electrolysis reduced chlorine concentration in the electrolyte and was detrimental to electrolysis efficiency, especially under high electric potential conditions. Therefore, the optimal choice of electrolysis time depends on the electrolyzable chloride in DOW and cell potential adopted for electrolysis. The higher the electric potential, the faster the chlorine level reaches its maximum, but the lower the electric efficiency will be.

  10. Effects of electrolysis time and electric potential on chlorine generation of electrolyzed deep ocean water.

    Science.gov (United States)

    Hsu, Guoo-Shyng Wang; Lu, Yi-Fa; Hsu, Shun-Yao

    2017-10-01

    Electrolyzed water is a sustainable disinfectant, which can comply with food safety regulations and is environmentally friendly. A two-factor central composite design was adopted for studying the effects of electrolysis time and electric potential on the chlorine generation efficiency of electrolyzed deep ocean water (DOW). DOW was electrolyzed in a glass electrolyzing cell equipped with platinum-plated titanium anode and cathode. The results showed that chlorine concentration reached maximal level in the batch process. Prolonged electrolysis reduced chlorine concentration in the electrolyte and was detrimental to electrolysis efficiency, especially under high electric potential conditions. Therefore, the optimal choice of electrolysis time depends on the electrolyzable chloride in DOW and cell potential adopted for electrolysis. The higher the electric potential, the faster the chlorine level reaches its maximum, but the lower the electric efficiency will be. Copyright © 2016. Published by Elsevier B.V.

  11. Influence of nitrogen source on NDMA formation during chlorination of diuron.

    Science.gov (United States)

    Chen, Wei-Hsiang; Young, Thomas M

    2009-07-01

    N-Nitrosodimethylamine (NDMA) is formed during chlorination of water containing the herbicide diuron (N'-(3,4-dichlorophenyl)-N,N-dimethylurea) but formation is greatly enhanced in the presence of ammonia (chloramination). Groundwater impacted by agricultural runoff may contain diuron and relatively high total nitrogen concentrations; this study examines the impact of the nitrogen form (ammonium, nitrite or nitrate) on NDMA formation during chlorination of such waters. NDMA formation during chlorination of diuron increased in the order nitriteNDMA formation in the presence of ammonium. Nitrate unexpectedly enhanced nitrosation of diuron derivatives to form NDMA compared to the cases of no added nitrogen or nitrite addition. Nitrite addition is less effective because it consumes more chlorine and produces intermediates that react rapidly with diuron and its aromatic byproducts. Differences between surface water and groundwater in nitrogen forms and concentrations and disinfection approaches suggest strategies to reduce NDMA formation should vary with drinking water source.

  12. Assessing microbiological water quality in drinking water distribution systems with disinfectant residual using flow cytometry.

    Science.gov (United States)

    Gillespie, Simon; Lipphaus, Patrick; Green, James; Parsons, Simon; Weir, Paul; Juskowiak, Kes; Jefferson, Bruce; Jarvis, Peter; Nocker, Andreas

    2014-11-15

    Flow cytometry (FCM) as a diagnostic tool for enumeration and characterization of microorganisms is rapidly gaining popularity and is increasingly applied in the water industry. In this study we applied the method to obtain a better understanding of total and intact cell concentrations in three different drinking water distribution systems (one using chlorine and two using chloramines as secondary disinfectants). Chloramine tended to result in lower proportions of intact cells than chlorine over a wider residual range, in agreement with existing knowledge that chloramine suppresses regrowth more efficiently. For chlorinated systems, free chlorine concentrations above 0.5 mg L(-1) were found to be associated with relatively low proportions of intact cells, whereas lower disinfectant levels could result in substantially higher percentages of intact cells. The threshold for chlorinated systems is in good agreement with guidelines from the World Health Organization. The fact that the vast majority of samples failing the regulatory coliform standard also showed elevated proportions of intact cells suggests that this parameter might be useful for evaluating risk of failure. Another interesting parameter for judging the microbiological status of water, the biological regrowth potential, greatly varied among different finished waters providing potential help for investment decisions. For its measurement, a simple method was introduced that can easily be performed by water utilities with FCM capability. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Degradation of chloramphenicol by UV/chlorine treatment: Kinetics, mechanism and enhanced formation of halonitromethanes.

    Science.gov (United States)

    Dong, Huiyu; Qiang, Zhimin; Hu, Jun; Qu, Jiuhui

    2017-09-15

    Ultraviolet (UV)/chlorine process is considered as an emerging advanced oxidation process for the degradation of micropollutants. This study investigated the degradation of chloramphenicol (CAP) and formation of disinfection by-products (DBPs) during the UV/chlorine treatment. It was found that CAP degradation was enhanced by combined UV/chlorine treatment compared to that of UV and chlorination treatment alone. The pseudo-first-order rate constant of the UV/chlorine process at pH 7.0 reached 0.016 s -1 , which was 10.0 and 2.0 folds that observed from UV and chlorination alone, respectively. The enhancement can be attributed to the formation of diverse radicals (HO and reactive chlorine species (RCSs)), and the contribution of RCSs maintained more stable than that of HO at pH 5.5-8.5. Meanwhile, enhanced DBPs formation during the UV/chlorine treatment was observed. Both the simultaneous formation and 24-h halonitromethanes formation potential (HNMsFP) were positively correlated with the UV/chlorine treatment time. Although the simultaneous trichloronitromethane (TCNM) formation decreased with the prolonged UV irradiation, TCNM dominated the formation of HNMs after 24 h (>97.0%). According to structural analysis of transformation by-products, both the accelerated CAP degradation and enhanced HNMs formation steps were proposed. Overall, the formation of diverse radicals during the UV/chlorine treatment accelerated the degradation of CAP, while also enhanced the formation of DBPs simultaneously, indicating the need for DBPs evaluation before the application of combined UV/chlorine process. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Efficacy of chlorine dioxide on Escherichia coli inactivation during pilot-scale fresh-cut lettuce processing

    NARCIS (Netherlands)

    Banach, J.L.; Overbeek, van L.S.; Nierop Groot, M.N.; Zouwen, van der P.S.; Fels-Klerx, van der H.J.

    2018-01-01

    Controlling water quality is critical in preventing cross-contamination during fresh produce washing. Process wash water (PWW) quality can be controlled by implementing chemical disinfection strategies. The aim of this study was to evaluate the pilot-scale efficacy of chlorine dioxide (ClO2) during

  15. Study of the effects of {gamma}-radiation followed by chlorination with hypochlorite on coliforms in sterile buffered samples

    Energy Technology Data Exchange (ETDEWEB)

    Tata, A.; Festinesi, A.; Rosa, R.; Adamo, A.; Rossi, G. [ENEA, Centro Ricerche Casaccia, Rome (Italy). Dipt. Innovazione

    1998-04-01

    Radiation and chlorination combined treatment of water samples is investigated in order to evaluate the disinfecting efficacy, observing the growth of reference organisms. [Italiano] Nel presente lavoro sono illustrati i risultati delle analisi condotte su campioni di acqua sottoposti a trattamento combinato con radiazioni e clorazione, al fine di valutare l`efficacia mediante l`osservazione della crescita di organismi di riferimento.

  16. 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.

  17. Unstable volatility

    DEFF Research Database (Denmark)

    Casas, Isabel; Gijbels, Irène

    2012-01-01

    The objective of this paper is to introduce the break-preserving local linear (BPLL) estimator for the estimation of unstable volatility functions for independent and asymptotically independent processes. Breaks in the structure of the conditional mean and/or the volatility functions are common...... in Finance. Nonparametric estimators are well suited for these events due to the flexibility of their functional form and their good asymptotic properties. However, the local polynomial kernel estimators are not consistent at points where the volatility function has a break. The estimator presented...

  18. Chlorine transportation risk assessment

    International Nuclear Information System (INIS)

    Lautkaski, Risto; Mankamo, Tuomas.

    1977-02-01

    An assessment has been made on the toxication risk of the population due to the bulk rail transportation of liquid chlorine in Finland. Fourteen typical rail accidents were selected and their probability was estimated using the accident file of the Finnish State Railways. The probability of a chlorine leak was assessed for each type of accident separately using four leak size categories. The assessed leakage probability was dominated by station accidents, especially by collisions of a chlorine tanker and a locomotive. Toxication hazard areas were estimated for the leak categories. A simple model was constructed to describe the centring of the densely populated areas along the railway line. A comparison was made between the obtained risk and some other risks including those due to nuclear reactor accidents. (author)

  19. Chlorination leaching of cadmium

    International Nuclear Information System (INIS)

    Lach, E.; Pajak, I.; Bojanowska, A.

    1978-01-01

    The results of the investigations on chlorination leaching of cadmium from dust coming from dry dust collector of sinter belt, that is leaching with water saturated with gaseous chlorine and leaching with solutions of ammonium chloride and sodium chloride were given. The optimum conditions for these processes were established. It was found, that the method of leaching in the presence of gaseous chlorine is more effective, as it allows to report into the solution over 90% cadmium contained in dust. Owing to technical difficulties, environmental protection and safety conditions more advantageous seems to be the use as leaching agent of the ammonium chloride solutions. When applying 20% NH 4 Cl and temperature of 60 0 C, the time of 2 hours and the ratio of solid to liquid of 1:5, 70% cadmium contained in the dust can be reported into the solution. (auth.)

  20. Halogenating reaction activity of aromatic organic compounds during disinfection of drinking water

    International Nuclear Information System (INIS)

    Guo Gaimei; Chen Xiaodong

    2009-01-01

    The halogenating reactions of five aromatic organic compounds (AOCs) with aqueous chlorine (HOCl/OCl - ) and aqueous bromine (HOBr/OBr - ) were studied with an aim to compare the formation properties of haloacetic acids (HAAs) for the corresponding chlorination or bromination reactions of AOCs, respectively. The experiment results indicated that the HAAs substitution efficiency for the bromination reactions of AOCs was greater than that for the chlorination reactions, and the formation of HAAs had a strong dependence on the chemical structure of AOCs. The chlorination or bromination reaction activities for the AOCs with electron donating functional groups were higher than that for them with electron withdrawing functional groups. The kinetic experiments indicated that the reactions of aqueous bromine with phenol were faster than those of aqueous chlorine with phenol and the halogen consumption exhibited rapid initial and slower consumption stages for the reactions of phenol with aqueous chlorine and bromine, respectively. In addition, the HAAs production for the chlorination reaction of phenol decreased with the increase of pH. These conclusions could provide the valuable information for the effective control of the disinfection by-products during drinking water treatment operation

  1. Chasing volatility

    DEFF Research Database (Denmark)

    Caporin, Massimiliano; Rossi, Eduardo; Santucci de Magistris, Paolo

    The realized volatility of financial returns is characterized by persistence and occurrence of unpreditable large increments. To capture those features, we introduce the Multiplicative Error Model with jumps (MEM-J). When a jump component is included in the multiplicative specification, the condi......The realized volatility of financial returns is characterized by persistence and occurrence of unpreditable large increments. To capture those features, we introduce the Multiplicative Error Model with jumps (MEM-J). When a jump component is included in the multiplicative specification...... estimate alternative specifications of the model using a set of daily bipower measures for 7 stock indexes and 16 individual NYSE stocks. The estimates of the jump component confirm that the probability of jumps dramatically increases during the financial crisis. Compared to other realized volatility...... models, the introduction of the jump component provides a sensible improvement in the fit, as well as for in-sample and out-of-sample volatility tail forecasts....

  2. 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.

  3. 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

  4. Inhibition of lipopolysaccharide induced acute inflammation in lung by chlorination.

    Science.gov (United States)

    Zhang, Jinshan; Xue, Jinling; Xu, Bi; Xie, Jiani; Qiao, Juan; Lu, Yun

    2016-02-13

    Lipopolysaccharide (LPS, also called endotoxin) is a pro-inflammatory constituent of gram negative bacteria and cyanobacteria, which causes a potential health risk in the process of routine urban application of reclaimed water, such as car wash, irrigation, scenic water refilling, etc. Previous studies indicated that the common disinfection treatment, chlorination, has little effect on endotoxin activity removal measured by Limulus amebocyte lysate (LAL) assay. However, in this study, significant decrease of acute inflammatory effects was observed in mouse lung, while LAL assay still presented a moderate increase of endotoxin activity. To explore the possible mechanisms, the nuclear magnetic resonance (NMR) results showed the chlorination happened in alkyl chain of LPS molecules, which could affect the interaction between LPS and LPS-binding protein. Also the size of LPS aggregates was found to drop significantly after treatment, which could be another results of chlorination caused polarity change. In conclusion, our observation demonstrated that chlorination is effective to reduce the LPS induced inflammation in lung, and it is recommended to use health effect-based methods to assess risk removal of water treatment technologies. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Inactivation of human and simian rotaviruses by chlorine dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yu-Shiaw (Brookhaven National Lab., Upton, NY (USA)); Vaughn, J.M. (Univ. of New England College of Medicine, Biddeford, ME (USA))

    1990-05-01

    The inactivation of single-particle stocks of human (type 2, Wa) and simian (SA-11) rotaviruses by chlorine dioxide was investigated. Experiments were conducted at 4{degree}C in a standard phosphate-carbonate buffer. Both virus types were rapidly inactivated, within 20 s under alkaline conditions, when chlorine dioxide concentrations ranging from 0.05 to 0.2 mg/liter were used. Similar reductions of 10{sup 5}-fold in infectivity required additional exposure time of 120 s at 0.2 mg/liter for Wa and at 0.5 mg/liter for SA-11, respectively, at pH 6.0. The inactivation of both virus types was moderate a neutral pH, and the sensitivities to chlorine dioxide were similar. The observed enhancement of virucidal efficiency with increasing pH was contrary to earlier findings with chlorine- and ozone-treated rotavirus particles, where efficiencies decreased with increasing alkalinity. Comparison of 99.9% virus inactivation times revealed ozone to be the most effective virucidal agent among these three disinfectants.

  6. Methylated silicates may explain the release of chlorinated methane from Martian soil

    Science.gov (United States)

    Bak, Ebbe N.; Jensen, Svend J. Knak; Nørnberg, Per; Finster, Kai

    2016-01-01

    The only organic compounds that have been detected in the Martian soil are simple chlorinated compounds released from heated surface material. However, the sources of the organic carbon are in dispute. Wind abraded silicates, which are widespread on the Martian surface, can sequester atmospheric methane which generates methylated silicates and thus could provide a mechanism for accumulation of reduced carbon in the surface soil. In this study we show that thermal volatilization of methylated silicates in the presence of perchlorate leads to the production of chlorinated methane. Thus, methylated silicates could be a source of the organic carbon released as chlorinated methane upon thermal volatilization of Martian soil samples. Further, our experiments show that the ratio of the different chlorinated compounds produced is dependent on the mass ratio of perchlorate to organic carbon in the soil.

  7. Methodology for modeling the disinfection efficiency of fresh-cut leafy vegetables wash water applied on peracetic acid combined with lactic acid.

    Science.gov (United States)

    Van Haute, S; López-Gálvez, F; Gómez-López, V M; Eriksson, Markus; Devlieghere, F; Allende, Ana; Sampers, I

    2015-09-02

    A methodology to i) assess the feasibility of water disinfection in fresh-cut leafy greens wash water and ii) to compare the disinfectant efficiency of water disinfectants was defined and applied for a combination of peracetic acid (PAA) and lactic acid (LA) and comparison with free chlorine was made. Standardized process water, a watery suspension of iceberg lettuce, was used for the experiments. First, the combination of PAA+LA was evaluated for water recycling. In this case disinfectant was added to standardized process water inoculated with Escherichia coli (E. coli) O157 (6logCFU/mL). Regression models were constructed based on the batch inactivation data and validated in industrial process water obtained from fresh-cut leafy green processing plants. The UV254(F) was the best indicator for PAA decay and as such for the E. coli O157 inactivation with PAA+LA. The disinfection efficiency of PAA+LA increased with decreasing pH. Furthermore, PAA+LA efficacy was assessed as a process water disinfectant to be used within the washing tank, using a dynamic washing process with continuous influx of E. coli O157 and organic matter in the washing tank. The process water contamination in the dynamic process was adequately estimated by the developed model that assumed that knowledge of the disinfectant residual was sufficient to estimate the microbial contamination, regardless the physicochemical load. Based on the obtained results, PAA+LA seems to be better suited than chlorine for disinfecting process wash water with a high organic load but a higher disinfectant residual is necessary due to the slower E. coli O157 inactivation kinetics when compared to chlorine. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. Biomarkers of end of shift exposure to disinfection byproducts in nurses.

    Science.gov (United States)

    Ioannou, Solomon; Andrianou, Xanthi D; Charisiadis, Pantelis; Makris, Konstantinos C

    2017-08-01

    Increased disinfectant use commonly takes place in hospitals and other health care settings. A cross-sectional study among active nurses in two Cypriot public hospitals (n=179) was conducted to examine the prevalence of exposure to disinfection byproducts (DBPs), such as trihalomethanes (THMs) using both self-reported information and biomarker measurements. The objectives of this study were to: i) quantify the magnitude and variability of occupational exposure to disinfectants/DBPs in nurses, ii) generate job exposure matrices (JEM) and job task exposure matrices (JTEM) for disinfectants, and iii) assess the major determinants of urinary THMs in nurses. End of shift urinary total THM values showed high variability among the nurses, but did not differ between hospitals. The disinfectant group of alcohols/phenols was used by >98% of nurses, followed by octenidine (82%), iodine and chlorine (39%, each), chlorhexidine (25%), formaldehyde (12%), hydrogen peroxide (11%), and peracetic acid/ammonia/quaternary ammonium compounds (QACs), all being Nurses were exposed to nearly double the levels of TTHMs and BrTHMs (median and IQR, 1027 [560, 2475] ng/g and 323 [212, 497] ng/g, respectively) when compared to those of the general population (552 [309,989] ng/g and 152 [87,261] ng/g, respectively). This was the first occupational health dataset reporting measurements of biomarkers of end of shift exposures to disinfectants/DBPs. Copyright © 2017. Published by Elsevier B.V.

  9. Effect of ionic environment on the inactivation of poliovirus in water by chlorine.

    OpenAIRE

    Sharp, D G; Young, D C; Floyd, R; Johnson, J D

    1980-01-01

    The rate of inactivation of poliovirus in water by chlorine is strongly influenced by the pH, which in turn influences the relative amounts of HOCl and OCl- that are present and acting on the virus in the region of pH 6 to 10. The distribution of HOCl and OCl- is influenced to a lesser extent by the addition of NaCl. The major part of the sharp increase in disinfection rate seen with this salt is thought to be due to its effect on the virus itself resulting in an increased chlorine sensitivit...

  10. 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…

  11. Epidemiological evidence of carcinogenicity of chlorinated organics in drinking water.

    Science.gov (United States)

    Cantor, K P

    1982-12-01

    Concern has recently been voiced over possible chronic toxicity associated with chlorination of public drinking water supplies in the United States. This paper reviews the available evidence and the studies underway to further evaluate hypothesized associations between cancer risk and byproducts of chlorination. Preliminary data from measures of halogenated volatiles and personal exposure histories from respondents in a large epidemiologic study of bladder cancer are presented. These data support the use in epidemiologic studies of categorical measures of exposure and suggest that results from completed case-control studies, based on death certificates, may have underestimated the true risk of exposure to chlorination by-products. The current generation of studies which use a case-control interview design offer many advantages over earlier efforts to evaluate this issue.

  12. The Use of Genetic Algorithms in UV Disinfection of Drinking Water

    OpenAIRE

    Hugo Zaldaña; Emerson Castañeda

    2015-01-01

    In order to have drinking water, some countries have to use chlorine. It is use cause is effective and it’s cheap. An alternative to this process is the UV disinfection of drinking water. Most of the devices in the market use UV bulbs or mercury lamps. The UV LED, which is cheaper and smaller, allows creating new smaller devices. The main contribution of this paper is the use of Genetic Algorithms to help design a drinking water device with UV LEDs.

  13. Validation of the analytical method for sodium dichloroisocyanurate aimed at drinking water disinfection

    International Nuclear Information System (INIS)

    Martinez Alvarez, Luis Octavio; Alejo Cisneros, Pedro; Garcia Pereira, Reynaldo; Campos Valdez, Doraily

    2014-01-01

    Cuba has developed the first effervescent 3.5 mg sodium dichloroisocyanurate tablets as a non-therapeutic active principle. This ingredient releases certain amount of chlorine when dissolved into a litre of water and it can cause adequate disinfection of drinking water ready to be taken after 30 min. Developing and validating an analytical iodometric method applicable to the quality control of effervescent 3.5 mg sodium dichloroisocyanurate tablets

  14. Disinfection in Wastewater Treatment Plants: Evaluation of Effectiveness and Acute Toxicity Effects

    Directory of Open Access Journals (Sweden)

    Maria Cristina Collivignarelli

    2017-09-01

    Full Text Available In Italy, urban wastewater disinfection is regulated in the third part of Legislative Decree n. 152/2006, which states that wastewater treatment plants (WWTPs must include a disinfection unit, with a capacity exceeding 2000 Population Equivalent (PE. This treatment shall ensure microbial quality and health security. The legislation provides the following limits for wastewater: Escherichia coli (E. coli concentration below 5000 CFU 100 mL−1 (recommended value, active chlorine concentration below 0.2 mg L−1 and lack of acute toxicity. The compliance with these conditions is shown by means of the study of correct disinfectant dosage, which also depends on wastewater characteristics. An investigation at the regional level (from 2013 to 2016 shows a correlation between acute toxicity discharge and disinfection treatment through chemical reagents (mainly with the use of chlorine compounds and peracetic acid. The experimental work concerns two active sludge WWTPs in northern Italy with small capacity (10,000–12,000 PE. The activities provide the assessment of microbiological quality and toxicity of WWTPs effluents in relation to the dosage of sodium hypochlorite and peracetic acid, by means of the use of batch tests. The results show that with similar disinfectant dosage and comparable initial E. coli concentration, peracetic acid exhibits the best performance in terms of microbial removal (with removal yields up to 99.99%. Moreover, the acute toxicity was evident at higher doses and therefore with higher residuals of peracetic acid (2.68 mg L−1 compared to the free residual chlorine (0.17 mg L−1.

  15. Kinetics of the oxidation of cylindrospermopsin and anatoxin-a with chlorine, monochloramine and permanganate.

    Science.gov (United States)

    Rodríguez, Eva; Sordo, Ana; Metcalf, James S; Acero, Juan L

    2007-05-01

    Cyanobacteria produce toxins that may contaminate drinking water sources. Among others, the presence of the alkaloid toxins cylindrospermopsin (CYN) and anatoxin-a (ANTX) constitutes a considerable threat to human health due to the acute and chronic toxicity of these compounds. In the present study, not previously reported second-order rate constants for the reactions of CYN and ANTX with chlorine and monochloramine and of CYN with potassium permanganate were determined and the influence of pH and temperature was established for the most reactive cases. It was found that the reactivity of CYN with chlorine presents a maximum at pH 7 (rate constant of 1265 M(-1)s(-1)). However, the oxidation of CYN with chloramine and permanganate are rather slow processes, with rate constants chlorination product of CYN was found to be 5-chloro-CYN (5-Cl-CYN), which reacts with chlorine 10-20 times slower than the parent compound. The reactivity of ANTX with chlorine and chloramines is also very low (kchlorine dose of 1.5 mg l(-1) was enough to oxidize CYN almost completely. However, 3 mg l(-1) of chlorine was able to remove only 8% of ANTX, leading to a total formation of trihalomethanes (TTHM) at a concentration of 150 microg l(-1). Therefore, chlorination is a feasible option for CYN degradation during oxidation and disinfection processes but not for ANTX removal. The permanganate dose required for CYN oxidation is very high and not applicable in waterworks.

  16. Where does Chlorine-36 go?

    International Nuclear Information System (INIS)

    Anon.

    2000-01-01

    Chlorine-36 and Iodine-129 are the unique long-life radionuclides in the halogen family and halogens are known to be very mobile in the environment. Chlorine-36 is present in slight quantities in radioactive wastes containing carbon or issued from spent fuel reprocessing. The migration of Chlorine-36 in the environment has been very little studied, so a collaboration between the French institute of protection and nuclear safety (IPSN) and the Ukrainian institute for agricultural radioecology (UIAR) has been launched. IPSN will study the migration of Chlorine-36 in soils and UIAR will be in charge of studying the transfer of Chlorine-36 from soil to plants. (A.C.)

  17. 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...

  18. Volatility in energy prices

    International Nuclear Information System (INIS)

    Duffie, D.

    1999-01-01

    This chapter with 58 references reviews the modelling and empirical behaviour of volatility in energy prices. Constant volatility and stochastic volatility are discussed. Markovian models of stochastic volatility are described and the different classes of Markovian stochastic volatility model are examined including auto-regressive volatility, option implied and forecasted volatility, Garch volatility, Egarch volatility, multivariate Garch volatility, and stochastic volatility and dynamic hedging policies. Other volatility models and option hedging are considered. The performance of several stochastic volatility models as applied to heating oil, light oil, natural gas, electricity and light crude oil are compared

  19. Effect of ultrasonic pretreatment on purified water disinfection; Efecto del pretratamiento con ultrasonidos sobre la desinfeccion de agua depurada

    Energy Technology Data Exchange (ETDEWEB)

    Simon Andreu, P.; Lardin Mifsut, C.; Vergara Romero, L.; Polo Canas, P. M.; Perez Sanchez, P.; Rancano Perez, A.

    2009-07-01

    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.

  20. Kinetics of membrane damage to high (HNA) and low (LNA) nucleic acid bacterial clusters in drinking water by ozone, chlorine, chlorine dioxide, monochloramine, ferrate(VI), and permanganate.

    Science.gov (United States)

    Ramseier, Maaike K; von Gunten, Urs; Freihofer, Pietro; Hammes, Frederik

    2011-01-01

    Drinking water was treated with ozone, chlorine, chlorine dioxide, monochloramine, ferrate(VI), and permanganate to investigate the kinetics of membrane damage of native drinking water bacterial cells. Membrane damage was measured by flow cytometry using a combination of SYBR Green I and propidium iodide (SGI+PI) staining as indicator for cells with permeabilized membranes and SGI alone to measure total cell concentration. SGI+PI staining revealed that the cells were permeabilized upon relatively low oxidant exposures of all tested oxidants without a detectable lag phase. However, only ozonation resulted in a decrease of the total cell concentrations for the investigated reaction times. Rate constants for the membrane damage reaction varied over seven orders of magnitude in the following order: ozone > chlorine > chlorine dioxide ≈ ferrate > permanganate > chloramine. The rate constants were compared to literature data and were in general smaller than previously measured rate constants. This confirmed that membrane integrity is a conservative and therefore safe parameter for disinfection control. Interestingly, the cell membranes of high nucleic acid (HNA) content bacteria were damaged much faster than those of low nucleic acid (LNA) content bacteria during treatment with chlorine dioxide and permanganate. However, only small differences were observed during treatment with chlorine and chloramine, and no difference was observed for ferrate treatment. Based on the different reactivity of these oxidants it was suggested that HNA and LNA bacterial cell membranes have a different chemical constitution. Copyright © 2010 Elsevier Ltd. All rights reserved.

  1. 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...

  2. Microbial chlorination of organic matter in forest soil: investigation using 36Cl-chloride and its methodology.

    Science.gov (United States)

    Rohlenová, J; Gryndler, M; Forczek, S T; Fuksová, K; Handova, V; Matucha, M

    2009-05-15

    Chloride, which comes into the forest ecosystem largely from the sea as aerosol (and has been in the past assumed to be inert), causes chlorination of soil organic matter. Studies of the chlorination showed that the content of organically bound chlorine in temperate forest soils is higher than that of chloride, and various chlorinated compounds are produced. Our study of chlorination of organic matter in the fermentation horizon of forest soil using radioisotope 36Cl and tracer techniques shows that microbial chlorination clearly prevails over abiotic, chlorination of soil organic matter being enzymatically mediated and proportional to chloride content and time. Long-term (>100 days) chlorination leads to more stable chlorinated substances contained in the organic layer of forest soil (overtime; chlorine is bound progressively more firmly in humic acids) and volatile organochlorines are formed. Penetration of chloride into microorganisms can be documented by the freezing/thawing technique. Chloride absorption in microorganisms in soil and in litter residues in the fermentation horizon complicates the analysis of 36Cl-chlorinated soil. The results show that the analytical procedure used should be tested for every soil type under study.

  3. Calcium hypochlorite as a disinfecting additive for dental stone.

    Science.gov (United States)

    Twomey, Jonathan O; Abdelaziz, Khalid M; Combe, Edward C; Anderson, Dwight L

    2003-09-01

    Dental casts come into direct contact with impression materials and other items that are contaminated by saliva and blood from a patient's mouth, leaving the casts susceptible to cross-contamination. Topical methods of disinfecting casts are difficult to control, while immersion methods are potentially destructive. Thus, an additional method to control cross-contamination between patients and laboratory personnel is needed. This study was undertaken in an attempt to develop a dental stone with disinfecting properties and adequate compressive and tensile strengths. Calcium hypochlorite [Ca(OCl)(2)] in aqueous solution in concentrations from 0 to 1.5% was tested as a disinfecting additive to type V dental stone. The compressive and tensile strength properties of the modified stone were measured (MPa) using a universal testing machine at a consistency similar to unmodified stone. Strength data were analyzed by 1-way ANOVA and post hoc Tukey-Kramer procedure (alpha CaviCide, and 3 impressions rinsed in water served as controls. In general, the effect of adding the disinfectant to the stone was a decrease in strength. Exceptions were the dry compressive strength, for which there was a significant increase in strength (P=.048) at 0.5%, and the wet compressive and wet tensile strength, which showed no significant difference between the 1.5% and the control. When Ca(OCl)(2) was added at the concentration 0.5% (2765 ppm available chlorine), the gypsum had acceptable mechanical properties; dry compressive strength was 78.86 +/- 4.12 MPa, and dry tensile strength was 10.64 +/- 1.27 MPa, compared to control values of 67.85 +/- 6.28 and 13.41 +/- 1.24 MPa, respectively. At concentrations of 0.3% and higher (36 1650 ppm of available chlorine), calcium hypochlorite was able to completely inactivate phi29. It is possible to prepare a type V dental stone that contains a disinfectant, has adequate mechanical properties, and will reduce numbers of residual microorganisms. For example

  4. Chemical disinfection of non-porous inanimate surfaces experimentally contaminated with four human pathogenic viruses.

    Science.gov (United States)

    Sattar, S A; Springthorpe, V S; Karim, Y; Loro, P

    1989-06-01

    The chemical disinfection of virus-contaminated non-porous inanimate surfaces was investigated using coxsackievirus B3, adenovirus type 5, parainfluenza virus type 3 and coronavirus 229E as representatives of important nosocomial viral pathogens. A 10 microliter amount of the test virus, suspended in either faeces or mucin, was placed onto each stainless steel disk (about 1 cm in diameter) and the inoculum allowed to dry for 1 h under ambient conditions. Sixteen disinfectant formulations were selected for this study based on the findings of an earlier investigation with a human rotavirus. After 1 min exposure to 20 microliters of the disinfectant, the virus from the disks was immediately eluted into tryptose phosphate broth and plaque assayed. Using an efficacy criterion of a 3 log10 or greater reduction in virus infectivity titre and irrespective of the virus suspending medium, only the following five disinfectants proved to be effective against all the four viruses tested: (1) 2% glutaraldehyde normally used as an instrument soak, (2) a strongly alkaline mixture of 0.5% sodium o-benzyl-p-chlorophenate and 0.6% sodium lauryl sulphate, generally used as a domestic disinfectant cleaner for hard surfaces, (3) a 0.04% solution of a quaternary ammonium compound containing 7% hydrochloric acid, which is the basis of many toilet bowl cleaners, (4) chloramine T at a minimum free chlorine level of 3000 p.p.m. and (5) sodium hypochlorite at a minimum free chlorine concentration of 5000 p.p.m. Of those chemicals suitable for use as topical antiseptics, 70% ethanol alone or products containing at least 70% ethanol were ineffective only against coxsackievirus B3. These results emphasize the care needed in selecting chemical disinfectants for routine use in infection control.

  5. Short-Term Changes in Respiratory Biomarkers after Swimming in a Chlorinated Pool

    OpenAIRE

    Font-Ribera, Laia; Kogevinas, Manolis; Zock, Jan-Paul; G?mez, Federico P.; Barreiro, Esther; Nieuwenhuijsen, Mark J.; Fernandez, Pilar; Lourencetti, Carolina; P?rez-Olabarr?a, Maitane; Bustamante, Mariona; Marcos, Ricard; Grimalt, Joan O.; Villanueva, Cristina M.

    2010-01-01

    Background Swimming in chlorinated pools involves exposure to disinfection by-products (DBPs) and has been associated with impaired respiratory health. Objectives We evaluated short-term changes in several respiratory biomarkers to explore mechanisms of potential lung damage related to swimming pool exposure. Methods We measured lung function and biomarkers of airway inflammation [fractional exhaled nitric oxide (FeNO), eight cytokines, and vascular endothelial growth factor (VEGF) in exhaled...

  6. Stochastic volatility of volatility in continuous time

    DEFF Research Database (Denmark)

    Barndorff-Nielsen, Ole; Veraart, Almut

    This paper introduces the concept of stochastic volatility of volatility in continuous time and, hence, extends standard stochastic volatility (SV) models to allow for an additional source of randomness associated with greater variability in the data. We discuss how stochastic volatility...... of volatility can be defined both non-parametrically, where we link it to the quadratic variation of the stochastic variance process, and parametrically, where we propose two new SV models which allow for stochastic volatility of volatility. In addition, we show that volatility of volatility can be estimated...

  7. [Chlorine coatings on skin surfaces. II. Parameters influencing the coating strength].

    Science.gov (United States)

    Gottardi, W; Karl, A

    1991-05-01

    Although active chlorine compounds have been used for more than 140 years (Semmelweis, 1848) as a skin disinfectant the phenomenon of the "chlorine covers" not earlier than 1988 has been described for the first time (Hyg. + Med. 13 (1988) 157). It deals with a chemical alteration of the uppermost skin layer which comes apparent in an oxydizing action against aqueous iodide. Its origin is chlorine covalently bound in the form of N-Cl functions to the protein matrix of the horny skin. Since the chlorine covers exhibit a persistant disinfecting activity which might be important for practice, the factors influencing their strength have been established. The most important are: the kind of the chlorine system, the concentration (oxydation capacity), pH, temperature and the volume of the used solution, the time of action, the application technique and the state of the skin. Variations of the latter can be observed at different skin areas of one and the same person as well as at the same areas of different persons, and result in differences of the cover strength up to 100%. The stability on dry skin is very good, showing a decomposition rate of approximately 1.2% per hour. However on skin surfaces moistened by sweat (e.g. hands covered by surgeons gloves) the chlorine cover is disingrated much more faster (decomposition rate: 40-50% per hour). Washing with soap as well as the action of alcohols cause virtually no decrease in the cover strength, while wetting by solutions of reducing agents (e.g. thiosulfate, cysteine, iodide) provokes a fast decomposition suitable for removing the chlorine covers.(ABSTRACT TRUNCATED AT 250 WORDS)

  8. Occurrences of nitrosamines in chlorinated and chloraminated drinking water in three representative cities, China

    International Nuclear Information System (INIS)

    Luo, Qian; Wang, Donghong; Wang, Zijian

    2012-01-01

    An investigation of the occurrence of nine nitrosamines in drinking water following different water treatment processes was conducted using samples from seven drinking water treatment plants in three cities and tap waters in one city in China. The total nitrosamine levels ranged from not detected (n.d.) to 43.45 ng/L. The species and concentrations of the nine nitrosamines varied with disinfection methods and source waters. N-nitrosodimethylamine (NDMA), which is the nitrosamines of greatest concern, was identified in raw water, disinfecting water, finished water and tap water samples, ranging from 0.8 to 21.6, 0.12 to 24.2, n.d. to 8.8, and n.d. to 13.3 ng/L, respectively. Chloramination alone produced the most significant amounts of NDMA, while ozonation followed by chloramination led to moderately reduced levels. Additionally, chlorination produced relatively less NDMA, while low pressure ultraviolet radiation followed by chlorination could also significantly reduce them. Total organic carbon is one of the most important factors influencing nitrosamines formation in disinfecting water. In contrast, the addition of chlorine following any other disinfection was found to increase the formation of the other eight species of nitrosamines. The three nitrosamines recommended for monitoring by the US EPA were detected in the tap water samples, but most were present at levels below those that pose a risk to human health. Nevertheless, the occurrence and concentration of nitrosamines regulated in the Drinking Water Contaminant Candidate List could cause some potential human effects and therefore warrant attention. Highlights: ► Nitrosamines in disinfected drinking water in three Chinese cities were investigated. ► Some nitrosamines could be detected in raw water. ► Advanced treatment affects nitrosamine levels both positively and negatively. ► Organic matters contribute to increased nitrosamine level. ► Nitrosamine levels in this study were below the EPA MAC but

  9. 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.

  10. Surface Disinfectants for Burn Units Evaluated by a New Double Method, Using Microorganisms Recently Isolated From Patients, on a Surface Germ-Carrier Model.

    Science.gov (United States)

    Herruzo, Rafael; Vizcaino, Maria Jose; Herruzo, Irene; Sanchez, Manuel

    Assessment methods of surface disinfection based on international standards (Environmental Protection Agency, European Norms, etc) do not correspond to hospital reality. New evaluation methods of surfaces disinfection are proposed to choose the most suitable disinfectant to act against clinically relevant microorganisms detected on the surfaces of burn units. 1) "Immediate effect": 6 products were compared using a glass germ-carrier and 20 recently isolated microorganisms from different patients in the intensive care units. Disinfectants were applied with microfiber cloths. Log10 reductions were calculated for colony forming units produced after 15 minutes of disinfectant application. 2) "Residual effect": the glass germ-carriers were previously impregnated with one of the studied disinfectants. After a 30-minute wait period, they were then contaminated with 1 microorganism (from the 20 above-mentioned). After 15 minutes, the disinfectant was inhibited and the log10 reduction of colony forming units was assessed. The immediate effect (disinfection and microorganism dragging and transferring from the surface to the cloth) produced complete elimination of the inoculums for all products used except one (a diluted quaternary ammonium). The average residual effect found on the 20 microorganisms was moderate: 2 to 3 log10 colony forming unit reduction with chlorine dioxide or 0.5% chlorhexidine (and lower with the other products), obtaining surfaces refractory to recontamination, at least, during 30 minutes. Two tests should be performed before advising surface disinfectant: 1) direct effect and 2) residual efficacy. These characteristics should be considered when a new surface disinfectant is chosen. Chlorine dioxide has a similar or better direct effect than sodium hypochlorite and a similar residual effect than chlorhexidine.

  11. Recovery of Actinides from Actinide-Aluminium Alloys: Chlorination Route

    International Nuclear Information System (INIS)

    Mendes, E.; Malmbeck, R.; Soucek, P.; Jardin, R.; Glatz, J.P.; Cassayre, L.

    2008-01-01

    A method for recovery of actinides (An) from An-Al alloys formed by electrochemical separation of metallic spent nuclear fuel on solid aluminium electrodes in molten chloride salts is described. The proposed route consists of three main steps: -) vacuum distillation of salt adhered on the electrodes, -) chlorination of An-Al alloy by pure chlorine gas and -) sublimation of formed AlCl 3 . A thermochemical study of the route was performed to determine important chemical reactions and to find optimum experimental conditions for all process steps. Vacuum distillation of the electrode is efficient for complete removal of remaining salt and most fission products, full chlorination of the An-Al alloys is possible at any working temperature and evaporation of AlCl 3 is achieved by heating under argon. Experiments have been carried out using U-Al alloy in order to define parameters providing full alloy chlorination without formation of volatile UCl 5 and UCl 6 . It was shown that full chlorination of An-Al alloys without An losses should be possible at a temperature approx. 150 deg. C. (authors)

  12. Recovery of Actinides from Actinide-Aluminium Alloys: Chlorination Route

    Energy Technology Data Exchange (ETDEWEB)

    Mendes, E.; Malmbeck, R.; Soucek, P.; Jardin, R.; Glatz, J.P. [European Commission, JRC, Institute for Transuranium Elements, Postfach 2340, 76125 Karlsruhe (Germany); Cassayre, L. [Laboratoire de Genie Chimique (LGC), Universite Paul Sabatier, UMR CNRS 5503, 118 route de Narbonne, 31062 Toulouse Cedex 04 (France)

    2008-07-01

    A method for recovery of actinides (An) from An-Al alloys formed by electrochemical separation of metallic spent nuclear fuel on solid aluminium electrodes in molten chloride salts is described. The proposed route consists of three main steps: -) vacuum distillation of salt adhered on the electrodes, -) chlorination of An-Al alloy by pure chlorine gas and -) sublimation of formed AlCl{sub 3}. A thermochemical study of the route was performed to determine important chemical reactions and to find optimum experimental conditions for all process steps. Vacuum distillation of the electrode is efficient for complete removal of remaining salt and most fission products, full chlorination of the An-Al alloys is possible at any working temperature and evaporation of AlCl{sub 3} is achieved by heating under argon. Experiments have been carried out using U-Al alloy in order to define parameters providing full alloy chlorination without formation of volatile UCl{sub 5} and UCl{sub 6}. It was shown that full chlorination of An-Al alloys without An losses should be possible at a temperature approx. 150 deg. C. (authors)

  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. Chlorination of zirconyte concentrate

    International Nuclear Information System (INIS)

    Costa, N.G.

    1988-01-01

    Chlorination experiments with zirconyte concentrate were carried out in order to study the effects of temperature, percentage of reducing agent and porosity on the gasification of ZrO 2 for 10 and 20 minutes of reaction. Factorial analysis was applied and the results indicated that temperature and percentage of reducing agent were the two only variables effecting the ZrO 2 gasification. (author) [pt

  16. Transformation of acesulfame in chlorination: Kinetics study, identification of byproducts, and toxicity assessment.

    Science.gov (United States)

    Li, Adela Jing; Wu, Pengran; Law, Japhet Cheuk-Fung; Chow, Chi-Hang; Postigo, Cristina; Guo, Ying; Leung, Kelvin Sze-Yin

    2017-06-15

    Acesulfame (ACE) is one of the most commonly used artificial sweeteners. Because it is not metabolized in the human gut, it reaches the aquatic environment unchanged. In the present study, the reactivity of ACE in free chlorine-containing water was investigated for the first time. The degradation of ACE was found to follow pseudo-first-order kinetics. The first-order rate increased with decreasing pH from 9.4 to 4.8 with estimated half-lives from 693 min to 2 min. Structural elucidation of the detected transformation products (TPs) was performed by ultra-high performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry. Integration of MS/MS fragments, isotopic pattern and exact mass allowed the characterization of up to 5 different TPs in the ultrapure water extracts analyzed, including two proposed new chlorinated compounds reported for the first time. Unexpectedly, several known and regulated disinfection by-products (DBPs) were present in the ACE chlorinated solution. In addition, two of the six DBPs are proposed as N-DBPs. Time-course profiles of ACE and the identified by-products in tap water and wastewater samples were followed in order to simulate the actual disinfection process. Tap water did not significantly affect degradation, but wastewater did; it reacted with the ACE to produce several brominated-DBPs. A preliminary assessment of chlorinated mixtures by luminescence inhibition of Vibrio fischeri showed that these by-products were up to 1.8-fold more toxic than the parent compound. The generation of these DBPs, both regulated and not, representing enhanced toxicity, make chlorine disinfection a controversial treatment for ACE. Further efforts are urgently needed to both assess the consequences of current water treatment processes on ACE and to develop new processes that will safely treat ACE. Human health and the health of our aquatic ecosystems are at stake. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Removal of uranium from simulated fly ash by chloride volatilization method

    International Nuclear Information System (INIS)

    Nobuaki, Sato; Yoshikatsu, Tochigi; Toshiki, Fukui; Takeo, Fujino

    2003-01-01

    Fly ash is generated from LWR nuclear power plant as a low-level waste, which is contaminated with a small amount of radioactive materials, composed mainly of uranium oxide. The constituents of the fly ash are similar to those of the ore; the major components of the ash are oxides of silicon, aluminum, sodium, magnesium, zinc, iron sodium and uranium. In this study, removal of uranium from the simulated fly ash, of which composition was U 3 O 8 : 10, CaO:25, SiO 2 : 25, Al 2 O 3 : 20, MgO: 10, ZnO:5, Fe 2 O 3 : 3 and Na 2 CO 3 : 2 wt%, by chloride volatilization method was examined. The simulated fly ash was chlorinated by the same manner as the dry way processing for the ore; namely, the ash was heated in a flow of chlorine in the presence of carbon at high temperatures. In the case of volatilization of uranium from U 3 O 8 and a simulated fly ash by chlorination using chlorine and carbon, it was seen that uranium of both samples showed similar volatilization behaviour: The volatilization ratio of uranium (VU) increased with increasing temperature from 800 to 1100 C. The VU value attained 99.9% at 1100 C. Iron, silicon and zinc showed similar behaviour to uranium, namely, they vaporized completely. The volatilization ratio of aluminum, magnesium and sodium were still high in a range 80-90%. The volatilization ratio of calcium was ∼40% under the same chlorination condition, though it changed to chloride. For recovery of uranium from fly ash by chlorination using chlorine in the presence of carbon, high volatilization ratio of uranium can be achieved at high temperatures. Volatilization ratio of other components also increases, which decreases the amount of decontaminated residue resulting in the reducing of decontamination effect. Selection of heating condition is important. (author)

  18. Mechanistic aspects of ingested chlorine dioxide on thyroid function: impact of oxidants on iodide metabolism

    International Nuclear Information System (INIS)

    Bercz, J.P.; Jones, L.L.; Harrington, R.M.; Bawa, R.; Condie, L.

    1986-01-01

    Toxicological studies dealing with recent findings of health effects of drinking water disinfectants are reviewed. Experiments with monkeys and rodents indicate that the biological activity of ingested disinfectants is expressed via their chemical interaction with the mucosal epithelia, secretory products, and nutritional contents of the alimentary tract. Evidence exists that a principal partner of this redox interaction is the iodide of nutritional origin that is ubiquitous in the gastrointestinal tract. Thus the observation that subchronic exposure to chlorine dioxide (ClO 2 ) in drinking water decreases serum thyroxine levels in mammalian species can be best explained with changes produced in the chemical form of the bioavailable iodide. Ongoing and previously reported mechanistic studies indicate that oxidizing agents such as chlorine-based disinfectants oxidize the basal iodide content of the gastrointestinal tract. The resulting reactive iodine species readily attaches to organic matter by covalent bonding. Evidence suggests that the extent to which such iodinated organics are formed is proportional to the magnitude of the electromotive force and stoichiometry of the redox couple between iodide and the disinfectant. Because the extent of thyroid uptake of the bioavailable iodide does not decrease during ClO 2 ingestion, it seems that ClO 2 does not cause iodide deficiency of sufficient magnitude to account for the decease in hormonogenesis. Absorption of one or more of iodinated molecules, e.g., nutrient, hormones, or cellular constituents of the alimentary tract having thyromimetic or thyroid inhibitory properties, is a better hypothesis for the effects seen

  19. Effect of pH on the formation of disinfection byproducts in swimming pool water – Is less THM better?

    DEFF Research Database (Denmark)

    Hansen, Kamilla Marie Speht; Willach, Sarah; Antoniou, Maria

    2012-01-01

    This study investigated the formation and predicted toxicity of different groups of disinfection byproducts (DBPs) from human exudates in relation to chlorination of pool water at different pH values. Specifically, the formation of the DBP groups trihalomethanes (THMs), haloacetic acids (HAAs......), haloacetonitriles (HANs) and trichloramine (NCl3), resulting from the chlorination of body fluid analog, were investigated at 6.0 ≤ pH ≤ 8.0. Either the initial concentration of active chorine or free chlorine was kept constant in the tested pH range. THM formation was reduced by decreasing pH but HAN, and NCl3...... formation was investigated and found to follow the same pH dependency as without bromide present, with the overall DBP formation increasing, except for HAAs. Estimation of genotoxicity and cytotoxicity of the chlorinated human exudates showed that among the quantified DBP groups, HAN formation were...

  20. Effects of chlorinated drinking water on the xenobiotic metabolism in Cyprinus carpio treated with samples from two Italian municipal networks.

    Science.gov (United States)

    Cirillo, Silvia; Canistro, Donatella; Vivarelli, Fabio; Paolini, Moreno

    2016-09-01

    Drinking water (DW) disinfection represents a milestone of the past century, thanks to its efficacy in the reduction of risks of epidemic forms by water micro-organisms. Nevertheless, such process generates disinfection by-products (DBPs), some of which are genotoxic both in animals and in humans and carcinogenic in animals. At present, chlorination is one of the most employed strategies but the toxicological effects of several classes of DBPs are unknown. In this investigation, a multidisciplinary approach foreseeing the chemical analysis of chlorinated DW samples and the study of its effects on mixed function oxidases (MFOs) belonging to the superfamily of cytochrome P450-linked monooxygenases of Cyprinus carpio hepatopancreas, was employed. The experimental samples derived from aquifers of two Italian towns (plant 1, river water and plant 2, spring water) were obtained immediately after the disinfection (A) and along the network (R1). Animals treated with plant 1 DW-processed fractions showed a general CYP-associated MFO induction. By contrast, in plant 2, a complex modulation pattern was achieved, with a general up-regulation for the point A and a marked MFO inactivation in the R1 group, particularly for the testosterone metabolism. Together, the toxicity and co-carcinogenicity (i.e. unremitting over-generation of free radicals and increased bioactivation capability) of DW linked to the recorded metabolic manipulation, suggests that a prolonged exposure to chlorine-derived disinfectants may produce adverse health effects.

  1. Mass Spectrometry Identification of N-Chlorinated Dipeptides in Drinking Water.

    Science.gov (United States)

    Huang, Guang; Jiang, Ping; Li, Xing-Fang

    2017-04-04

    We report the identification of N-chlorinated dipeptides as chlorination products in drinking water using complementary high-resolution quadrupole time-of-flight (QTOF) and quadrupole ion-trap mass spectrometry techniques. First, three model dipeptides, tyrosylglycine (Tyr-Gly), tyrosylalanine (Tyr-Ala), and phenylalanylglycine (Phe-Gly), reacted with sodium hypochlorite, and these reaction solutions were analyzed by QTOF. N-Cl-Tyr-Gly, N,N-di-Cl-Tyr-Gly, N-Cl-Phe-Gly, N,N-di-Cl-Phe-Gly, N-Cl-Tyr-Ala, and N,N-di-Cl-Tyr-Ala were identified as the major products based on accurate masses, 35 Cl/ 37 Cl isotopic patterns, and MS/MS spectra. These identified N-chlorinated dipeptides were synthesized and found to be stable in water over 10 days except N,N-di-Cl-Phe-Gly. To enable sensitive detection of N-chlorinated dipeptides in authentic water, we developed a high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method with multiple reaction monitoring (MRM) mode. N-Cl-Tyr-Gly, N,N-di-Cl-Tyr-Gly, N-Cl-Phe-Gly, N-Cl-Tyr-Ala, and N,N-di-Cl-Tyr-Ala along with their corresponding dipeptides were detected in authentic tap water samples. The dipeptides were clearly detected in the raw water, but the N-chlorinated dipeptides were at background levels. These results suggest that the N-chlorinated dipeptides are produced by chlorination. This study has identified N-chlorinated dipeptides as new disinfection byproducts in drinking water. The strategy developed in this study can be used to identify chlorination products of other peptides in drinking water.

  2. 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...

  3. Effects of UV irradiation and UV/chlorine co-exposure on natural organic matter in water

    International Nuclear Information System (INIS)

    Liu, Wei; Zhang, Zaili; Yang, Xin; Xu, Yiyue; Liang, Yongmei

    2012-01-01

    The effects of co-exposure to ultraviolet (UV) irradiation (with either low- or medium-pressure UV lamps) and free chlorine (chloramine) at practical relevant conditions on changes in natural organic matter (NOM) properties were investigated using four waters. The changes were characterized using the specific disinfection by-product formation potential (SDBPFP), specific total organic halogen formation potential (STOXFP), differential UV absorbance (∆UVA), and size-exclusion chromatography (SEC). The results for exposure to UV irradiation alone and for samples with no exposure were also obtained. The SDBPFPs in all UV-irradiated NOM waters observed were higher than those of non-irradiated samples. UV irradiation led to increases in STOXFPs as a result of chlorination, but no changes, or only small decreases, from chloramination. UV irradiation alone led to positive ∆UVA spectra of the four NOM waters; co-exposure to UV and chlorine gave larger negative ∆UVA spectra than those obtained by chlorine exposure alone. No obvious changes in SEC results were observed for samples only irradiated with UV light; co-exposure gave no detectable changes in the abundances of small fractions for exposure to chlorine only. Both UV photooxidation and photocatalytic oxidation appear to affect the reactivity of the NOM toward subsequent chlorination, and the magnitude of the changes is generally greater for medium-pressure lamps than for low-pressure lamps. These results suggest that applying UV disinfection technology to a particular source may not always be disinfection by-product-problem-free, and the interactions between UV light, chlorine, and NOM may need to be considered. - Highlights: ► We discussed the effects of co-exposure to UV light and chlorine on properties of natural organic matters in waters. ► UV irradiation led to increases in SDBPFP and STOXFP of NOM waters from chlorination. ► We suggest that applying an UV disinfection technology to a particular

  4. Bacterial Community Shift Drives Antibiotic Resistance Promotion during Drinking Water Chlorination.

    Science.gov (United States)

    Jia, Shuyu; Shi, Peng; Hu, Qing; Li, Bing; Zhang, Tong; Zhang, Xu-Xiang

    2015-10-20

    For comprehensive insights into the effects of chlorination, a widely used disinfection technology, on bacterial community and antibiotic resistome in drinking water, this study applied high-throughput sequencing and metagenomic approaches to investigate the changing patterns of antibiotic resistance genes (ARGs) and bacterial community in a drinking water treatment and distribution system. At genus level, chlorination could effectively remove Methylophilus, Methylotenera, Limnobacter, and Polynucleobacter, while increase the relative abundance of Pseudomonas, Acidovorax, Sphingomonas, Pleomonas, and Undibacterium in the drinking water. A total of 151 ARGs within 15 types were detectable in the drinking water, and chlorination evidently increased their total relative abundance while reduced their diversity in the opportunistic bacteria (p < 0.05). Residual chlorine was identified as the key contributing factor driving the bacterial community shift and resistome alteration. As the dominant persistent ARGs in the treatment and distribution system, multidrug resistance genes (mainly encoding resistance-nodulation-cell division transportation system) and bacitracin resistance gene bacA were mainly carried by chlorine-resistant bacteria Pseudomonas and Acidovorax, which mainly contributed to the ARGs abundance increase. The strong correlation between bacterial community shift and antibiotic resistome alteration observed in this study may shed new light on the mechanism behind the chlorination effects on antibiotic resistance.

  5. Metagenomic insights into chlorination effects on microbial antibiotic resistance in drinking water.

    Science.gov (United States)

    Shi, Peng; Jia, Shuyu; Zhang, Xu-Xiang; Zhang, Tong; Cheng, Shupei; Li, Aimin

    2013-01-01

    This study aimed to investigate the chlorination effects on microbial antibiotic resistance in a drinking water treatment plant. Biochemical identification, 16S rRNA gene cloning and metagenomic analysis consistently indicated that Proteobacteria were the main antibiotic resistant bacteria (ARB) dominating in the drinking water and chlorine disinfection greatly affected microbial community structure. After chlorination, higher proportion of the surviving bacteria was resistant to chloramphenicol, trimethoprim and cephalothin. Quantitative real-time PCRs revealed that sulI had the highest abundance among the antibiotic resistance genes (ARGs) detected in the drinking water, followed by tetA and tetG. Chlorination caused enrichment of ampC, aphA2, bla(TEM-1), tetA, tetG, ermA and ermB, but sulI was considerably removed (p water chlorination could concentrate various ARGs, as well as of plasmids, insertion sequences and integrons involved in horizontal transfer of the ARGs. Water pipeline transportation tended to reduce the abundance of most ARGs, but various ARB and ARGs were still present in the tap water, which deserves more public health concerns. The results highlighted prevalence of ARB and ARGs in chlorinated drinking water and this study might be technologically useful for detecting the ARGs in water environments. Copyright © 2012 Elsevier Ltd. All rights reserved.

  6. 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.

  7. 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.

  8. The efficiency of different disinfecting agents in inactivating microorganisms detected in natural and treated waters; Eficiencia de diferentes agentes desinfectantes en la inactivacion de microorganismos detectados en aguas naturales y tratadas

    Energy Technology Data Exchange (ETDEWEB)

    Perez Recuerda, R.; Sanchez, J.M.; Borrego, J.J.

    1998-12-01

    The efficiency of microbial inactivation and sublethal injury of six disinfectants (chlorine, chloramines, uV-light, potassium permanganate, fluor and ozone) applied at different dose on several bacterial strains, yeast and viruses has been studied comparatively. Disinfectant effect was higher on Gramnegative bacteria (Salmonella, Pseudomonas, Escherichia and Klebsiella) than on Gram-positive (Clostridium, Enterococcus and Stanphylococcus); although the least inactivation effect was obtained on the MS-2 bacteriophage. The global efficiency ranking of the disinfectants assayed to produce the microbial inactivation was as follows; ozone>chlorine>UV-light>chloramines>permanganate>fluor. On the other hand, on Escherichia coli and Pseudomonas aerugionosa were observed the highest sublethal injuries provokes by the disinfectants and dose assayed. Therefore, these microorganisms are the main candidates to regrow and to form biofilm in drinking water distribution systems. 34 refs. (Author)

  9. ENVIROMETAL TECHNOLOGIES, INC., METAL-ENHANCED DECHLORINATION OF VOLATILE ORGANIC COMPOUNDS USING AN IN-SITU REACTIVE IRON WALL

    Science.gov (United States)

    This report summarizes the results of a field demonstration conducted under the SITE program. The technology that was demonstrated was a metal-enhanced dechlorination process developed by EnviroMetal Technologies, Inc. to treat groundwater contaminated with chlorinated volatile ...

  10. 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

  11. The influence of disinfectants on mutagenicity and on toxicity of urban waste water; Valutazione di trattamenti di disinfezione di acque reflue urbane mediante test di tossicita' e di mutagenesi

    Energy Technology Data Exchange (ETDEWEB)

    Monarca, S. [Brescia Univ., Brescia (IT). Dipt. di Medicina Sperimentale e Applicata] [and others

    1999-12-01

    The aim of the research was to study the influence of disinfectants alternative to chlorine, such as chlorine dioxide, ozone, peracetic acid and UV radiation, have on the formation of mutagenic and toxic compounds in waste water disinfection. Preliminary results are presented and discussed. [Italian] Scopo del lavoro e' stato lo studio dell'azione antimicrobica di diversi disinfettanti su acque reflue urbane dopo trattamento secondario, correlando tale parametro con l'attivita' tossica e genotossica prodotta dalla disinfezione. I risultati vengono presentati e discussi.

  12. Reduction in health risk induced by semi-volatile organic compounds and metals in a drinking water treatment plant

    International Nuclear Information System (INIS)

    Zhao, F.; Yin, J.; Zhang, X. X.; Chen, Y.; Zhang, Y.; Wu, B.; Li, M.

    2015-01-01

    This study investigated health risk reduction in a drinking water treatment plant of Nanjing City (China) based on chemical detection of 22 semi-volatile organic compounds (SVOCs) and 24 metallic elements in source water and drinking water during 2009–2011. Chemical analysis showed that 15 SVOCs and 9 metals were present in the water. Health risk assessment revealed that hazard quotient of each pollutant and hazard index (HI) of all the detectable pollutants were below 1.00, indicating that the chemicals posed negligible non-carcinogenic risk to local residents. Benzo(a)pyrene may induce carcinogenic risk since its risk index via both oral and dermal exposure exceeded the safety level (1.00E-6), but other SVOCs induced no carcinogenic risk. Total HI of the SVOCs was 1.08E-3 for the source water and 1.56E-3 for the drinking water, suggesting that the used conventional treatment processes (coagulation/sedimentation, sand filtration and chlorine disinfection) cannot effectively reduce the non-carcinogenic risk. The source water had higher carcinogenic risk than the drinking water, but risk index of the drinking water still exceeded 1.00E-6. This study might serve as a basis for health risk assessment of drinking water and also as a benchmark for the authorities to reduce health risk arising from trace-level hazardous pollutants.

  13. [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.

  14. Occurrences of nitrosamines in chlorinated and chloraminated drinking water in three representative cities, China.

    Science.gov (United States)

    Luo, Qian; Wang, Donghong; Wang, Zijian

    2012-10-15

    An investigation of the occurrence of nine nitrosamines in drinking water following different water treatment processes was conducted using samples from seven drinking water treatment plants in three cities and tap waters in one city in China. The total nitrosamine levels ranged from not detected (n.d.) to 43.45 ng/L. The species and concentrations of the nine nitrosamines varied with disinfection methods and source waters. N-nitrosodimethylamine (NDMA), which is the nitrosamines of greatest concern, was identified in raw water, disinfecting water, finished water and tap water samples, ranging from 0.8 to 21.6, 0.12 to 24.2, n.d. to 8.8, and n.d. to 13.3 ng/L, respectively. Chloramination alone produced the most significant amounts of NDMA, while ozonation followed by chloramination led to moderately reduced levels. Additionally, chlorination produced relatively less NDMA, while low pressure ultraviolet radiation followed by chlorination could also significantly reduce them. Total organic carbon is one of the most important factors influencing nitrosamines formation in disinfecting water. In contrast, the addition of chlorine following any other disinfection was found to increase the formation of the other eight species of nitrosamines. The three nitrosamines recommended for monitoring by the US EPA were detected in the tap water samples, but most were present at levels below those that pose a risk to human health. Nevertheless, the occurrence and concentration of nitrosamines regulated in the Drinking Water Contaminant Candidate List could cause some potential human effects and therefore warrant attention. Copyright © 2012 Elsevier B.V. All rights reserved.

  15. 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.

  16. 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.

  17. 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...

  18. 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.

  19. The Dutch secret: how to provide safe drinking water without chlorine in the Netherlands

    Directory of Open Access Journals (Sweden)

    G. J. Medema

    2009-03-01

    Full Text Available The Netherlands is one of the few countries where chlorine is not used at all, neither for primary disinfection nor to maintain a residual disinfectant in the distribution network. The Dutch approach that allows production and distribution of drinking water without the use of chlorine while not compromising microbial safety at the tap, can be summarized as follows:
    1. Use the best source available, in order of preference:
        – microbiologically safe groundwater,
        – surface water with soil passage such as artificial recharge or bank filtration,
        – direct treatment of surface water in a multiple barrier treatment;
    2. Use a preferred physical process treatment such as sedimentation, filtration and UV-disinfection. If absolutely necessary, also oxidation by means of ozone or peroxide can be used, but chlorine is avoided;
    3. Prevent ingress of contamination during distribution;
    4. Prevent microbial growth in the distribution system by production and distribution of biologically stable (biostable water and the use of biostable materials;
    5. Monitor for timely detection of any failure of the system to prevent significant health consequences.

    New developments in safe drinking water in the Netherlands include the adaptation of the Dutch drinking water decree, implementation of quantitative microbial risk assessment (QMRA by water companies and research into source water quality, drinking water treatment efficacy, safe distribution and biostability of drinking water during distribution and Legionella. This paper summarizes how the Dutch water companies warrant the safety of the drinking water without chlorine.

  20. Use of peracetic acid in disinfection of wastewater: a review

    Directory of Open Access Journals (Sweden)

    Grasiele Soares Cavallini

    2012-04-01

    Full Text Available The use of peracetic acid (PAA to disinfect the wastewater has been researched for diverse authors, mainly in European countries, where the microbiological standards to release the effluents in water bodies are more severe and the moderation to use chlorine, due to the raising of trihalometanos is recommended. In this perspective, this work presents a compilation of researches applied directly to environmental sanitation, as well as the researches related to chemical characteristics of PAA and its reaction mechanisms. The combination of this information gives a theoretical and practical view of the use of this oxidant, which contributes to continue the researches in this area, aiming to benefit the environment, economy and public health system.

  1. 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.

  2. Pricing Volatility Referenced Assets

    Directory of Open Access Journals (Sweden)

    Alan De Genaro Dario

    2006-12-01

    Full Text Available Volatility swaps are contingent claims on future realized volatility. Variance swaps are similar instruments on future realized variance, the square of future realized volatility. Unlike a plain vanilla option, whose volatility exposure is contaminated by its asset price dependence, volatility and variance swaps provide a pure exposure to volatility alone. This article discusses the risk-neutral valuation of volatility and variance swaps based on the framework outlined in the Heston (1993 stochastic volatility model. Additionally, the Heston (1993 model is calibrated for foreign currency options traded at BMF and its parameters are used to price swaps on volatility and variance of the BRL / USD exchange rate.

  3. Field data analysis of active chlorine-containing stormwater samples.

    Science.gov (United States)

    Zhang, Qianyi; Gaafar, Mohamed; Yang, Rong-Cai; Ding, Chen; Davies, Evan G R; Bolton, James R; Liu, Yang

    2018-01-15

    Many municipalities in Canada and all over the world use chloramination for drinking water secondary disinfection to avoid DBPs formation from conventional chlorination. However, the long-lasting monochloramine (NH 2 Cl) disinfectant can pose a significant risk to aquatic life through its introduction into municipal storm sewer systems and thus fresh water sources by residential, commercial, and industrial water uses. To establish general total active chlorine (TAC) concentrations in discharges from storm sewers, the TAC concentration was measured in stormwater samples in Edmonton, Alberta, Canada, during the summers of 2015 and 2016 under both dry and wet weather conditions. The field-sampling results showed TAC concentration variations from 0.02 to 0.77 mg/L in summer 2015, which exceeds the discharge effluent limit of 0.02 mg/L. As compared to 2015, the TAC concentrations were significantly lower during the summer 2016 (0-0.24 mg/L), for which it is believed that the higher precipitation during summer 2016 reduced outdoor tap water uses. Since many other cities also use chloramines as disinfectants for drinking water disinfection, the TAC analysis from Edmonton may prove useful for other regions as well. Other physicochemical and biological characteristics of stormwater and storm sewer biofilm samples were also analyzed, and no significant difference was found during these two years. Higher density of AOB and NOB detected in the storm sewer biofilm of residential areas - as compared with other areas - generally correlated to high concentrations of ammonium and nitrite in this region in both of the two years, and they may have contributed to the TAC decay in the storm sewers. The NH 2 Cl decay laboratory experiments illustrate that dissolved organic carbon (DOC) concentration is the dominant factor in determining the NH 2 Cl decay rate in stormwater samples. The high DOC concentrations detected from a downstream industrial sampling location may contribute to a

  4. Biological instability in a chlorinated drinking water distribution network.

    Science.gov (United States)

    Nescerecka, Alina; Rubulis, Janis; Vital, Marius; Juhna, Talis; Hammes, Frederik

    2014-01-01

    The purpose of a drinking water distribution system is to deliver drinking water to the consumer, preferably with the same quality as when it left the treatment plant. In this context, the maintenance of good microbiological quality is often referred to as biological stability, and the addition of sufficient chlorine residuals is regarded as one way to achieve this. The full-scale drinking water distribution system of Riga (Latvia) was investigated with respect to biological stability in chlorinated drinking water. Flow cytometric (FCM) intact cell concentrations, intracellular adenosine tri-phosphate (ATP), heterotrophic plate counts and residual chlorine measurements were performed to evaluate the drinking water quality and stability at 49 sampling points throughout the distribution network. Cell viability methods were compared and the importance of extracellular ATP measurements was examined as well. FCM intact cell concentrations varied from 5×10(3) cells mL(-1) to 4.66×10(5) cells mL(-1) in the network. While this parameter did not exceed 2.1×10(4) cells mL(-1) in the effluent from any water treatment plant, 50% of all the network samples contained more than 1.06×10(5) cells mL(-1). This indisputably demonstrates biological instability in this particular drinking water distribution system, which was ascribed to a loss of disinfectant residuals and concomitant bacterial growth. The study highlights the potential of using cultivation-independent methods for the assessment of chlorinated water samples. In addition, it underlines the complexity of full-scale drinking water distribution systems, and the resulting challenges to establish the causes of biological instability.

  5. Disinfectants - bacterial cells interactions in the view of hygiene and public health

    Directory of Open Access Journals (Sweden)

    Marta Książczyk

    2015-09-01

    Full Text Available In recent years, the use of biocides has increased rapidly. One common example is triclosan, with wide application in households as well as medical and industrial fields, especially food industry and animal husbandry. Chemical disinfection is a major mean to control and eliminate pathogenic bacteria, particularly those with multidrug resistance (MDR phenotype. However, exposition to biocides results in an adaptive response in microorganisms, causing them to display a wide range of resistance mechanisms. Numerous microorganisms are characterized by either natural resistance to chemical compounds or an ability to adapt to biocides using various strategies, such as: modification of cell surface structures (lipopolisaccharide, membrane fatty acids, over-expression of efflux pumps (a system for active transport of toxic compounds out of bacterial cell, enzymatic inactivation of biocides or altering biocide targets. For instance, it was shown that in vitro exposition of Salmonella Typhimurium to subinhibitory concentration of biocides (triclosan, quaternary ammonium compounds [QACs] resulted in selection of variants resistant to tested biocides and, additionally, to acridine dyes and antibiotics. Bacillus subtilis and Micrococcus luteus strains isolated from chlorine dioxide containing disinfection devices were found to be resistant to chlorine dioxide and also to other oxidizing compounds, such as peracetic acid and hydrogen peroxide. Interaction between chemical compounds, including disinfectants and microbial cells, can create a serious threat to public health and sanitary-hygienic security. This phenomenon is connected with factor risk that intensify the probability of selection and dissemination of multidrug resistance among pathogenic bacteria.

  6. Studies with solid chlorine chemical for chlorination of sea water systems

    International Nuclear Information System (INIS)

    Sankar, N.; Kumaraswamy, P.; Santhanam, V.S.; Jeena, P.; Hari Krishna, K.; Rajendran, D.

    2015-01-01

    Chlorination is one of the conventional methods to control biofouling of condenser cooling water systems using either river water, reservoir water or sea water. However, there are many safety concerns associated with handling, storage and application of gaseous chlorine. Studies were carried out with suitable alternative chlorine chemical compounds which do not involve majority of these concerns but meet the functional requirement of gas chlorine. Trichloroisocyanuric Acid (TCCA) is one of the suitable alternatives to Gas chlorine. TCCA is a chlorine stabilized compound, stabilized with Cyanuric acid, thus similar to Gas Chlorine in its functions except that it is available in solid form. Release of chlorine is a gradual process in TCCA unlike Gaseous chlorine. Field studies with TCCA indicated gradual and near uniform release rate of chlorine, for longer duration with the requisite free residual chlorine levels (FRC). Thus, use of TCCA could be considered as a suitable alternative for gas chlorine for regular chlorination requirements. (author)

  7. A low-energy intensive electrochemical system for the eradication of Escherichia coli from ballast water: Process development, disinfection chemistry, and kinetics modeling

    International Nuclear Information System (INIS)

    Nadeeshani Nanayakkara, K.G.; Khorshed Alam, A.K.M.; Zheng Yuming; Paul Chen, J.

    2012-01-01

    The invasion of biological organisms via ballast water has created threats to the environment and human health. In this study, a cost-effective electrochemical disinfection reactor was developed to inactivate Escherichia coli, one of the IMO-regulated indicator microbes, in simulated ballast water. The complete inactivation of E. coli could be achieved within a very short time (150, 120, or 60 s) with an energy consumption as low as 0.0090, 0.0074 or 0.0035 kWh/m 3 for ballast water containing E. coli at concentrations of 10 8 , 10 7 and 10 6 CFU/100 mL, respectively. Electrochemical chlorination was the major disinfection mechanism in chloride-abundant electrolytes, whereas oxidants such as ozone and free radicals contributed to 20% of the disinfection efficiency in chloride-free electrolytes. Moreover, a disinfection kinetics model was successfully developed to describe the inactivation of E. coli.

  8. Estimation of optimum experimental parameters in chlorination of UO2 with Cl2 gas and carbon for UCl4

    International Nuclear Information System (INIS)

    Yang, Y.S.; Kang, Y.H.; Lee, H.K.

    1997-01-01

    For the preparation of uranium tetrachloride, the chlorination of UO 2 was carried out and an appropriate reaction system was confirmed. The effects of reaction temperature, time, injection ratio of N 2 gas and appropriate amount of carbon using a reductant on the conversion ratio and volatilization were evaluated. The optimum reaction time and temperature in chlorination of UO 2 for the preparation of UCl 4 were 2 h and 500-700 C, respectively. Also 50% of N 2 gas in chlorine gas proved to be the appropriate injection ratio. (orig.)

  9. Photodynamic tissue adhesion with chlorin(e6) protein conjugates.

    Science.gov (United States)

    Khadem, J; Veloso, A A; Tolentino, F; Hasan, T; Hamblin, M R

    1999-12-01

    To test the hypothesis that a photodynamic laser-activated tissue solder would perform better in sealing scleral incisions when the photosensitizer was covalently linked to the protein than when it was noncovalently mixed. Conjugates and mixtures were prepared between the photosensitizer chlorin(e6) and various proteins (albumin, fibrinogen, and gelatin) in different ratios and used to weld penetrating scleral incisions made in human cadaveric eyes. A blue-green (488-514 nm) argon laser activated the adhesive, and the strength of the closure was measured by increasing the intraocular pressure until the wound showed leakage. Both covalent conjugates and noncovalent mixtures showed a light dose-dependent increase in leaking pressure. A preparation of albumin chlorin(e6) conjugate with additional albumin added (2.5 protein to chlorin(e6) molar ratio) showed significantly higher weld strength than other protein conjugates and mixtures. This is the first report of dye-protein conjugates as tissue solders. These conjugates may have applications in ophthalmology.

  10. Chlorination and chloramination of bisphenol A, bisphenol F, and bisphenol A diglycidyl ether in drinking water.

    Science.gov (United States)

    Lane, Rachael F; Adams, Craig D; Randtke, Stephen J; Carter, Ray E

    2015-08-01

    Bisphenol A (BPA), bisphenol F (BPF), and bisphenol A diglycidyl ether (BADGE) are common components of epoxy coatings used in food packaging and in drinking water distribution systems. Thus, leachates from the epoxy may be exposed to the disinfectants free chlorine (Cl2/HOCl/OCl(-)) and monochloramine (MCA, NH2Cl). Bisphenols are known endocrine disrupting chemicals (EDC) with estrogenic activity. Chlorination by-products have the potential to have reduced or enhanced estrogenic qualities, and are, therefore, of interest. In this work, chlorination reactions for bisphenols and BADGE were explored (via LC/MS/MS) and kinetic modeling (using a pseudo-first order approach) was conducted to predict the fate of these compounds in drinking water. The half-lives of BPA and BPF with 1 mg/L of free chlorine ranged from 3 to 35 min over the pH range from 6 to 11 and the temperature range of 10-25 °C. Half-lives for reactions of BPA and BPF with a nominal MCA concentration of 3.5 mg/L as Cl2 were from 1 to 10 days and were greater at higher pH and lower temperature. Formation of chlorinated bisphenol A by-products was observed during the kinetic studies. BADGE was found unreactive with either oxidant. Copyright © 2015. Published by Elsevier Ltd.

  11. Chlorinated Phospholipids and Fatty Acids: (Pathophysiological Relevance, Potential Toxicity, and Analysis of Lipid Chlorohydrins

    Directory of Open Access Journals (Sweden)

    Jenny Schröter

    2016-01-01

    Full Text Available Chlorinated phospholipids are formed by the reaction of hypochlorous acid (HOCl, generated by the enzyme myeloperoxidase under inflammatory conditions, and the unsaturated fatty acyl residues or the head group. In the first case the generated chlorohydrins are both proinflammatory and cytotoxic, thus having a significant impact on the structures of biomembranes. The latter case leads to chloramines, the properties of which are by far less well understood. Since HOCl is also widely used as a disinfecting and antibacterial agent in medicinal, industrial, and domestic applications, it may represent an additional source of danger in the case of abuse or mishandling. This review discusses the reaction behavior of in vivo generated HOCl and biomolecules like DNA, proteins, and carbohydrates but will focus on phospholipids. Not only the beneficial and pathological (toxic effects of chlorinated lipids but also the importance of these chlorinated species is discussed. Some selected cleavage products of (chlorinated phospholipids and plasmalogens such as lysophospholipids, (chlorinated free fatty acids and α-chloro fatty aldehydes, which are all well known to massively contribute to inflammatory diseases associated with oxidative stress, will be also discussed. Finally, common analytical methods to study these compounds will be reviewed with focus on mass spectrometric techniques.

  12. Persistence of pharmaceuticals and other organic compounds in chlorinated drinking water as a function of time

    Science.gov (United States)

    Gibs, J.; Stackelberg, P.E.; Furlong, E.T.; Meyer, M.; Zaugg, S.D.; Lippincott, R.L.

    2007-01-01

    Ninety eight pharmaceuticals and other organic compounds (POOCs) that were amended to samples of chlorinated drinking-water were extracted and analyzed 1, 3, 6, 8, and 10 days after amendment to determine whether the total chlorine residual reacted with the amended POOCs in drinking water in a time frame similar to the residence time of drinking water in a water distribution system. Results indicated that if all 98 were present in the finished drinking water from a drinking-water treatment plant using free chlorine at 1.2??mg/L as the distribution system disinfectant residual, 52 POOCs would be present in the drinking water after 10??days at approximately the same concentration as in the newly finished drinking water. Concentrations of 16 POOCs would be reduced by 32% to 92%, and 22 POOCs would react completely with residual chlorine within 24??h. Thus, the presence of free chlorine residual is an effective means for transforming some POOCs during distribution. ?? 2006 Elsevier B.V. All rights reserved.

  13. Evaluating the effects of granular and membrane filtrations on chlorine demand in drinking water.

    Science.gov (United States)

    Jegatheesan, Veeriah; Kim, Seung Hyun; Joo, C K; Gao, Baoyu

    2009-01-01

    In this study, chlorine decay experiments were conducted for the raw water from Nakdong River that is treated by Chilseo Water Treatment Plant (CWTP) situated in Haman, Korea as well as the effluents from sand and granular activated carbon (GAC) filters of CWTP and fitted using a chlorine decay model. The model estimated the fast and slow reacting nitrogenous as well as organic/inorganic compounds that were present in the water. It was found that the chlorine demand due to fast and slow reacting (FRA and SRA) organic/inorganic substances was not reduced significantly by sand as well as GAC filters. However, the treated effluents from those filters contained FRA and SRA that are less reactive and had small reaction rate constants. For the effluents from microfiltration, ultrafiltration, and nanofiltration the chlorine demand because FRA and SRA were further reduced but the reaction rate constants were larger compared to those of sand and GAC filter effluents. This has implications in the formation of disinfection by products (DBPs). If DBPs are assumed to form due to the interactions between chlorine and SRA, then it is possible that the DBP formation potential in the effluents from membrane filtrations could be higher than that in the effluents from granular media filters.

  14. Activity of disinfectants and biofilm production of Corynebacterium pseudotuberculosis

    Directory of Open Access Journals (Sweden)

    Maria da C.A. Sá

    2013-11-01

    Full Text Available To verify the occurrence of caseous lymphadenitis in sheep and goats on farms of Pernambuco, Brazil, and in animals slaughtered in two Brazilian cities (Petrolina/PE and Juazeiro/BA, and to characterize the susceptibility profile of Corynebacterium pseudotuberculosis to disinfectants and antimicrobials, and its relationship with biofilm production were the objectives of this study. 398 samples were tested for sensitivity to antimicrobial drugs, disinfectants, and biofilm production. Among the 108 samples collected on the properties, 75% were positive for C. pseudotuberculosis. Slaughterhouse samples indicated an occurrence of caseous lymphadenitis in 15.66% and 6.31% for animals slaughtered in Petrolina and Juazeiro respectively. With respect to antimicrobials, the sensitivity obtained was 100% for florfenicol and tetracycline; 99.25% for enrofloxacin, ciprofloxacin and lincomycin; 98.99% for cephalothin; 98.74% for norfloxacin and sulfazotrim; 97.74% for gentamicin; 94.22% for ampicillin; 91.71% for amoxicillin; 91.21% for penicillin G; 89.19% for neomycin and 0% for novobiocin. In analyzes with disinfectants, the efficiency for chlorhexidine was 100%, 97.20% for quaternary ammonium, 87.40% for chlorine and 84.40% for iodine. 75% of the isolates were weak or non-biofilm producers. For the consolidated biofilm, found that iodine decreased biofilm formation in 13 isolates and quaternary ammonia in 11 isolates. The reduction of the biofilm formation was observed for iodine and quaternary ammonium in consolidated biofilm formation in 33% and 28% of the isolates, respectively. The results of this study highlight the importance of establishing measures to prevent and control the disease.

  15. Free chlorine and monochloramine inactivation kinetics of Aspergillus and Penicillium in drinking water.

    Science.gov (United States)

    Ma, Xiao; Bibby, Kyle

    2017-09-01

    Fungi are near-ubiquitous in potable water distribution systems, but the disinfection kinetics of commonly identified fungi are poorly studied. In the present study, laboratory scale experiments were conducted to evaluate the inactivation kinetics of Aspergillus fumigatus, Aspergillus versicolor, and Penicillium purpurogenum by free chlorine and monochloramine. The observed inactivation data were then fit to a delayed Chick-Watson model. Based on the model parameter estimation, the Ct values (integrated product of disinfectant concentration C and contact time t over defined time intervals) for 99.9% inactivation of the tested fungal strains ranged from 48.99 mg min/L to 194.7 mg min/L for free chlorine and from 90.33 mg min/L to 531.3 mg min/L for monochloramine. Fungal isolates from a drinking water system (Aspergillus versicolor and Penicillium purpurogenum) were more disinfection resistant than Aspergillus fumigatus type and clinical isolates. The required 99.9% inactivation Ct values for the tested fungal strains are higher than E. coli, a commonly monitored indicator bacteria, and within a similar range for bacteria commonly identified within water distribution systems, such as Mycobacterium spp. and Legionella spp. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Transformation of avobenzone in conditions of aquatic chlorination and UV-irradiation.

    Science.gov (United States)

    Trebše, Polonca; Polyakova, Olga V; Baranova, Maria; Kralj, Mojca Bavcon; Dolenc, Darko; Sarakha, Mohamed; Kutin, Alexander; Lebedev, Albert T

    2016-09-15

    Emerging contaminants represent a wide group of the most different compounds. They appear in the environment at trace levels due to human activity. Most of these compounds are not yet regulated. Sunscreen UV-filters play an important role among these emerging contaminants. In the present research the reactions of 4-tert-butyl-4'-methoxydibenzoylmethane (avobenzone), the most common UV filter in the formulation of sunscreens, were studied under the combined influence of active chlorine and UV-irradiation. Twenty five compounds were identified by GC/MS as transformation products of avobenzone in reactions of aquatic UV-irradiation and chlorination with sodium hypochlorite. A complete scheme of transformation of avobenzone covering all the semivolatile products is proposed. The identification of the two primary chlorination products (2-chloro-1-(4-tert-butylphenyl)-3-(4-methoxyphenyl)-1,3-propanedione and 2,2-dichloro-1-(4-tert-butylphenyl)-3-(4-methoxyphenyl)-1,3-propanedione) was confirmed by their synthesis and GC/MS and NMR analysis. Although the toxicities of the majority of these products remain unknown substituted chlorinated phenols and acetophenones are known to be rather toxic. Combined action of active chlorine and UV-irradiation results in the formation of some products (chloroanhydrides, chlorophenols) not forming in conditions of separate application of these disinfection methods. Therefore caring for people «well-being» it is of great importance to apply the most appropriate disinfection method. Since the primary transformation products partially resist powerful UV-C irradiation they may be treated as stable and persistent pollutants. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Chlorine decay under steady and unsteady-state hydraulic conditions

    DEFF Research Database (Denmark)

    Stoianov, Ivan; Aisopou, Angeliki

    2014-01-01

    This paper describes a simulation framework for the scale-adaptive hydraulic and chlorine decay modelling under steady and unsteady-state flows. Bulk flow and pipe wall reaction coefficients are replaced with steady and unsteady-state reaction coefficients. An unsteady decay coefficient is defined...... which depends upon the absolute value of shear stress and the rate of change of shear stress for quasi-unsteady and unsteady-state flows. A preliminary experimental and analytical investigation was carried out in a water transmission main. The results were used to model monochloramine decay...... and these demonstrate that the dynamic hydraulic conditions have a significant impact on water quality deterioration and the rapid loss of disinfectant residual. © 2013 The Authors....

  18. Grundfoss: Chlorination of Swimming Pools

    DEFF Research Database (Denmark)

    Hjorth, Poul G.; Hogan, John; Andreassen, Viggo

    1998-01-01

    Grundfos asked for a model, describing the problem of mixing chemicals, being dosed into water systems, to be developed. The application of the model should be dedicated to dosing aqueous solution of chlorine into swimming pools.......Grundfos asked for a model, describing the problem of mixing chemicals, being dosed into water systems, to be developed. The application of the model should be dedicated to dosing aqueous solution of chlorine into swimming pools....

  19. Comparison of chlorine and chloramine in the release of mercury from dental amalgam.

    Science.gov (United States)

    Stone, Mark E; Scott, John W; Schultz, Stephen T; Berry, Denise L; Wilcoxon, Monte; Piwoni, Marv; Panno, Brent; Bordson, Gary

    2009-01-01

    The purpose of this project was to compare the ability of chlorine (HOCl/OCl(-)) and monochloramine (NH(2)Cl) to mobilize mercury from dental amalgam. Two types of amalgam were used in this investigation: laboratory-prepared amalgam and samples obtained from dental-unit wastewater. For disinfectant exposure simulations, 0.5 g of either the laboratory-generated or clinically obtained amalgam waste was added to 250 mL amber bottles. The amalgam samples were agitated by end-over-end rotation at 30 rpm in the presence of 1 mg/L chlorine, 10 mg/L chlorine, 1 mg/L monochloramine, 10 mg/L monochloramine, or deionized water for intervals of 0 h, 2 h, 4 h, 8 h, and 24 h for the clinically obtained amalgam waste samples and 4 h and 24 h for the laboratory-prepared samples. Chlorine and monochloramine concentrations were measured with a spectrophotometer. Samples were filtered through a 0.45 microm membrane filter and analyzed for mercury with USEPA standard method 245.7. When the two sample types were combined, the mean mercury level in the 1 mg/L chlorine group was 0.020 mg/L (n=25, SD=0.008). The 10 mg/L chlorine group had a mean mercury concentration of 0.59 mg/L (n=25, SD=1.06). The 1 mg/L chloramine group had a mean mercury level of 0.023 mg/L (n=25, SD=0.010). The 10 mg/L chloramine group had a mean mercury level of 0.024 mg/L (n=25, SD=0.011). Independent samples t-tests showed that there was a significant difference between the natural log mercury measurements of 10 mg/L chlorine compared to those of 1 mg/L and 10 mg/L chloramine. Changing from chlorine to chloramine disinfection at water treatment plants would not be expected to produce substantial increases in dissolved mercury levels in dental-unit wastewater.

  20. 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

    Full Text Available The objective of the study: to analyze efficiency of an aerosol method of M. tuberculosis deactivation in the air and on surfaces versus the conventional methods of the disinfectants' application.Subjects and Methods. The article describes the evaluation of efficiency of the aerosol method of M. tuberculosis, H37Rv strain, deactivation on surfaces (tested objects made of linoleum and in the air using the disinfectant of Green Dez based on chlorine dioxide versus deactivation through wiping and irrigation.The efficiency of disinfectant was tested by the device of 099С А4224 manufactured by Glas-Col, USA, using the air sampler of PU-1B, Russia.The Mobile Hygienic Center (MNC, Russia, was used for application of the disinfectant, wiping and irrigation was done using the disperser of Avtomaks AO-2, Russia.The bacterial aerosol was generated in the Glass-Col chamber with the concentration 5 ± 2.5 × 102 CFU/cm3, by spraying the suspension of M. tuberculosis, H37Rv strain. After that, the disinfectant spray was supplied to the chamber, where linoleum objects were placed horizontally on a variety of surfaces. In order to evaluate efficiency of surface treatment by wiping, the test objects were wiped with a tissue, soaked with the solution of Green Dez, based on consumption of 100-150 ml/m2. In 15, 30 and 60 minutes, the samples of inactivated M. tuberculosis aerosol were collected using an aspirator, chambers with test objects were closed and placed in the vent hood. To monitor efficiency of disinfection of the test object surfaces, the rinse blanks were done by wiping the surface with a sterile gauze wad, soaked with 0.5% of sodium thiosulfate solution.The samples of deactivated aerosol and rinse blanks from the surfaces of test objects were put into Petri dishes with Middlebrook 7H11 medium. The cultures were incubated in the thermostat at the temperature of 37 ± 1° C for 10-21 days, and the number of colonies was counted.Sterile water was used

  1. Fungicidal effect of 15 disinfectants against 25 fungal contaminants commonly found in bread and cheese manufacturing.

    Science.gov (United States)

    Bundgaard-Nielsen, K; Nielsen, P V

    1996-03-01

    Resistance of 19 mold and 6 yeast species to 15 commercial disinfectants was investigated by using a suspension method in which the fungicidal effect and germination time were determined at 20 degrees C. Disinfectants containing 0.5% dodecyldiethylentriaminacetic acid, 10 g of chloramine-T per 1, 2.0% formaldehyde, 0.1% potassium hydroxide, 3.0% hydrogen peroxide, or 0.3% peracetic acid were ineffective as fungicides. The fungicidal effect of quaternary ammonium compounds and chlorine compounds showed great variability between species and among the six isolates of Penicillium roqueforti var. roqueforti tested. The isolates of P roqueforti var. carneum, P. discolor, Aspergillus versicolor, and Eurotium repens examined were resistant to different quaternary ammonium compounds. Conidia and vegetative cells were killed by alcohols, whereas ascospores were resistant. Resistance of ascospores to 70% ethanol increased with age. Both P. roqueforti var. roqueforti and E. repens showed great variability of resistance within isolates of each species.

  2. Differences in field effectiveness and adoption between a novel automated chlorination system and household manual chlorination of drinking water in Dhaka, Bangladesh: a randomized controlled trial.

    Directory of Open Access Journals (Sweden)

    Amy J Pickering

    Full Text Available The number of people served by networked systems that supply intermittent and contaminated drinking water is increasing. In these settings, centralized water treatment is ineffective, while household-level water treatment technologies have not been brought to scale. This study compares a novel low-cost technology designed to passively (automatically dispense chlorine at shared handpumps with a household-level intervention providing water disinfection tablets (Aquatab, safe water storage containers, and behavior promotion. Twenty compounds were enrolled in Dhaka, Bangladesh, and randomly assigned to one of three groups: passive chlorinator, Aquatabs, or control. Over a 10-month intervention period, the mean percentage of households whose stored drinking water had detectable total chlorine was 75% in compounds with access to the passive chlorinator, 72% in compounds receiving Aquatabs, and 6% in control compounds. Both interventions also significantly improved microbial water quality. Aquatabs usage fell by 50% after behavioral promotion visits concluded, suggesting intensive promotion is necessary for sustained uptake. The study findings suggest high potential for an automated decentralized water treatment system to increase consistent access to clean water in low-income urban communities.

  3. Differences in Field Effectiveness and Adoption between a Novel Automated Chlorination System and Household Manual Chlorination of Drinking Water in Dhaka, Bangladesh: A Randomized Controlled Trial

    Science.gov (United States)

    Pickering, Amy J.; Crider, Yoshika; Amin, Nuhu; Bauza, Valerie; Unicomb, Leanne; Davis, Jennifer; Luby, Stephen P.

    2015-01-01

    The number of people served by networked systems that supply intermittent and contaminated drinking water is increasing. In these settings, centralized water treatment is ineffective, while household-level water treatment technologies have not been brought to scale. This study compares a novel low-cost technology designed to passively (automatically) dispense chlorine at shared handpumps with a household-level intervention providing water disinfection tablets (Aquatab), safe water storage containers, and behavior promotion. Twenty compounds were enrolled in Dhaka, Bangladesh, and randomly assigned to one of three groups: passive chlorinator, Aquatabs, or control. Over a 10-month intervention period, the mean percentage of households whose stored drinking water had detectable total chlorine was 75% in compounds with access to the passive chlorinator, 72% in compounds receiving Aquatabs, and 6% in control compounds. Both interventions also significantly improved microbial water quality. Aquatabs usage fell by 50% after behavioral promotion visits concluded, suggesting intensive promotion is necessary for sustained uptake. The study findings suggest high potential for an automated decentralized water treatment system to increase consistent access to clean water in low-income urban communities. PMID:25734448

  4. Differences in field effectiveness and adoption between a novel automated chlorination system and household manual chlorination of drinking water in Dhaka, Bangladesh: a randomized controlled trial.

    Science.gov (United States)

    Pickering, Amy J; Crider, Yoshika; Amin, Nuhu; Bauza, Valerie; Unicomb, Leanne; Davis, Jennifer; Luby, Stephen P

    2015-01-01

    The number of people served by networked systems that supply intermittent and contaminated drinking water is increasing. In these settings, centralized water treatment is ineffective, while household-level water treatment technologies have not been brought to scale. This study compares a novel low-cost technology designed to passively (automatically) dispense chlorine at shared handpumps with a household-level intervention providing water disinfection tablets (Aquatab), safe water storage containers, and behavior promotion. Twenty compounds were enrolled in Dhaka, Bangladesh, and randomly assigned to one of three groups: passive chlorinator, Aquatabs, or control. Over a 10-month intervention period, the mean percentage of households whose stored drinking water had detectable total chlorine was 75% in compounds with access to the passive chlorinator, 72% in compounds receiving Aquatabs, and 6% in control compounds. Both interventions also significantly improved microbial water quality. Aquatabs usage fell by 50% after behavioral promotion visits concluded, suggesting intensive promotion is necessary for sustained uptake. The study findings suggest high potential for an automated decentralized water treatment system to increase consistent access to clean water in low-income urban communities.

  5. Effect of Electrolyzed Water on the Disinfection of Bacillus cereus Biofilms: The Mechanism of Enhanced Resistance of Sessile Cells in the Biofilm Matrix.

    Science.gov (United States)

    Hussain, Mohammad Shakhawat; Kwon, Minyeong; Tango, Charles Nkufi; Oh, Deog Hwan

    2018-05-01

    This study examined the disinfection efficacy and mechanism of electrolyzed water (EW) on Bacillus cereus biofilms. B. cereus strains, ATCC 14579 and Korean Collection for Type Cultures (KCTC) 13153 biofilms, were formed on stainless steel (SS) and plastic slide (PS) coupons. Mature biofilms were treated with slightly acidic EW (SAEW), acidic EW (AEW), and basic EW (BEW). SAEW (available chlorine concentration, 25 ± 1.31 mg L -1 ; pH 5.71 ± 0.16; and oxidation reduction potential, 818 to 855 mV) reduced ATCC 14579 biofilms on plastic slides to below the detection limit within 30 s. However, biofilms on SS coupons showed a higher resistance to the SAEW treatment. When the disinfection activities of three types of EW on biofilms were compared, AEW showed a higher bactericidal activity, followed by SAEW and BEW. In contrast, BEW showed a significantly ( P biofilm dispersal activity than AEW and SAEW. SAEW disinfection of the B. cereus biofilms was due to the disruption of the B. cereus plasma membrane. The higher resistance of biofilms formed on the SS coupon might be due to the higher number of attached cells and extracellular polymeric substances formation that reacts with the active chlorine ions, such as hypochlorous acid and hypochlorite ion of SAEW, which decreased the disinfection efficacy of SAEW. This study showed that the EW treatment effectively disinfected B. cereus biofilms, providing insight into the potential use of EW in the food processing industry to control the biofilm formation of B. cereus.

  6. Degradation of lipid regulators by the UV/chlorine process: Radical mechanisms, chlorine oxide radical (ClO•)-mediated transformation pathways and toxicity changes.

    Science.gov (United States)

    Kong, Xiujuan; Wu, Zihao; Ren, Ziran; Guo, Kaiheng; Hou, Shaodong; Hua, Zhechao; Li, Xuchun; Fang, Jingyun

    2018-06-15

    Degradation of three lipid regulators, i.e., gemfibrozil, bezafibrate and clofibric acid, by a UV/chlorine treatment was systematically investigated. The chlorine oxide radical (ClO • ) played an important role in the degradation of gemfibrozil and bezafibrate with second-order rate constants of 4.2 (±0.3) × 10 8  M -1  s -1 and 3.6 (±0.1) × 10 7  M -1  s -1 , respectively, whereas UV photolysis and the hydroxyl radical (HO • ) mainly contributed to the degradation of clofibric acid. The first-order rate constants (k') for the degradation of gemfibrozil and bezafibrate increased linearly with increasing chlorine dosage, primarily due to the linear increase in the ClO • concentration. The k' values for gemfibrozil, bezafibrate, and clofibric acid degradation decreased with increasing pH from 5.0 to 8.4; however, the contribution of the reactive chlorine species (RCS) increased. Degradation of gemfibrozil and bezafibrate was enhanced in the presence of Br - , whereas it was inhibited in the presence of natural organic matter (NOM). The presence of ammonia at a chlorine: ammonia molar ratio of 1:1 resulted in decreases in the k' values for gemfibrozil and bezafibrate of 69.7% and 7%, respectively, but led to an increase in that for clofibric acid of 61.8%. Degradation of gemfibrozil by ClO • was initiated by hydroxylation and chlorine substitution on the benzene ring. Then, subsequent hydroxylation, bond cleavage and chlorination reactions led to the formation of more stable products. Three chlorinated intermediates were identified during ClO • oxidation process. Formation of the chlorinated disinfection by-products chloral hydrate and 1,1,1-trichloropropanone was enhanced relative to that of other by-products. The acute toxicity of gemfibrozil to Vibrio fischeri increased significantly when subjected to direct UV photolysis, whereas it decreased when oxidized by ClO • . This study is the first to report the transformation pathway of a

  7. Amide Link Scission in the Polyamide Active Layers of Thin-Film Composite Membranes upon Exposure to Free Chlorine: Kinetics and Mechanisms.

    Science.gov (United States)

    Powell, Joshua; Luh, Jeanne; Coronell, Orlando

    2015-10-20

    The volume-averaged amide link scission in the aromatic polyamide active layer of a reverse osmosis membrane upon exposure to free chlorine was quantified at a variety of free chlorine exposure times, concentrations, and pH and rinsing conditions. The results showed that (i) hydroxyl ions are needed for scission to occur, (ii) hydroxide-induced amide link scission is a strong function of exposure to hypochlorous acid, (iii) the ratio between amide links broken and chlorine atoms taken up increased with the chlorination pH and reached a maximum of ∼25%, (iv) polyamide disintegration occurs when high free chlorine concentrations, alkaline conditions, and high exposure times are combined, (v) amide link scission promotes further chlorine uptake, and (vi) scission at the membrane surface is unrepresentative of volume-averaged scission in the active layer. Our observations are consistent with previously proposed mechanisms describing amide link scission as a result of the hydrolysis of the N-chlorinated amidic N-C bond due to nucleophilic attack by hydroxyl ions. This study increases the understanding of the physicochemical changes that could occur for membranes in treatment plants using chlorine as an upstream disinfectant and the extent and rate at which those changes would occur.

  8. 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.

  9. The Use of Genetic Algorithms in UV Disinfection of Drinking Water

    Directory of Open Access Journals (Sweden)

    Hugo Zaldaña

    2015-06-01

    Full Text Available In order to have drinking water, some countries have to use chlorine. It is use cause is effective and it’s cheap. An alternative to this process is the UV disinfection of drinking water. Most of the devices in the market use UV bulbs or mercury lamps. The UV LED, which is cheaper and smaller, allows creating new smaller devices. The main contribution of this paper is the use of Genetic Algorithms to help design a drinking water device with UV LEDs.

  10. Depletion of chlorine into HCl ice in a protostellar core. The CHESS spectral survey of OMC-2 FIR 4

    Science.gov (United States)

    Kama, M.; Caux, E.; López-Sepulcre, A.; Wakelam, V.; Dominik, C.; Ceccarelli, C.; Lanza, M.; Lique, F.; Ochsendorf, B. B.; Lis, D. C.; Caballero, R. N.; Tielens, A. G. G. M.

    2015-02-01

    Context. The freezeout of gas-phase species onto cold dust grains can drastically alter the chemistry and the heating-cooling balance of protostellar material. In contrast to well-known species such as carbon monoxide (CO), the freezeout of various carriers of elements with abundances <10-5 has not yet been well studied. Aims: Our aim here is to study the depletion of chlorine in the protostellar core, OMC-2 FIR 4. Methods: We observed transitions of HCl and H2Cl+ towards OMC-2 FIR 4 using the Herschel Space Observatory and Caltech Submillimeter Observatory facilities. Our analysis makes use of state of the art chlorine gas-grain chemical models and newly calculated HCl-H2 hyperfine collisional excitation rate coefficients. Results: A narrow emission component in the HCl lines traces the extended envelope, and a broad one traces a more compact central region. The gas-phase HCl abundance in FIR 4 is 9 × 10-11, a factor of only 10-3 that of volatile elemental chlorine. The H2Cl+ lines are detected in absorption and trace a tenuous foreground cloud, where we find no depletion of volatile chlorine. Conclusions: Gas-phase HCl is the tip of the chlorine iceberg in protostellar cores. Using a gas-grain chemical model, we show that the hydrogenation of atomic chlorine on grain surfaces in the dark cloud stage sequesters at least 90% of the volatile chlorine into HCl ice, where it remains in the protostellar stage. About 10% of chlorine is in gaseous atomic form. Gas-phase HCl is a minor, but diagnostically key reservoir, with an abundance of ≲10-10 in most of the protostellar core. We find the [35Cl]/[37Cl] ratio in OMC-2 FIR 4 to be 3.2 ± 0.1, consistent with the solar system value. Appendices are available in electronic form at http://www.aanda.org

  11. Stability and `volatility ` of element 104 oxychloride

    Energy Technology Data Exchange (ETDEWEB)

    Eichler, B.; Gaeggeler, H.W. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-09-01

    The formation enthalpies {Delta}H{sup *} of solid and gaseous oxychlorides of element 104 from free atoms were estimated by extrapolation. Stability and volatility of these compounds are compared to those of the homologous and neighbouring elements in the periodic system. It can be supposed that in a gas adsorption chromatographic process with oxygen containing chlorinating carrier gas the transport with the carrier gas flow occurs in the chemical state 104Cl{sub 4}. Only in the absorbed state the compound 104OCl{sub 2} is formed. (author) 1 fig., 3 refs.

  12. Comparative assessment of chlorine, heat, ozone, and UV light for killing Legionella pneumophila within a model plumbing system

    International Nuclear Information System (INIS)

    Muraca, P.; Stout, J.E.; Yu, V.L.

    1987-01-01

    Nosocomial Legionnaires disease can be acquired by exposure to the organism from the hospital water distribution system. As a result, many hospitals have instituted eradication procedures, including hypercholorination and thermal eradication. We compared the efficacy of ozonation, UV light, hyperchlorination, and heat eradication using a model plumbing system constructed of copper piping, brass spigots, Plexiglas reservoir, electric hot water tank, and a pump. Legionella pneumophila was added to the system at 10(7) CFU/ml. Each method was tested under three conditions; (i) nonturbid water at 25 degrees C, (ii) turbid water at 25 degrees C, and (iii) nonturbid water at 43 degrees C. UV light and heat killed L. pneumophila most rapidly and required minimal maintenance. Both UV light and heat (60 degrees C) produced a 5 log kill in less than 1 h. In contrast, both chlorine and ozone required 5 h of exposure to produce a 5 log decrease. Neither turbidity nor the higher temperature of 43 degrees C impaired the efficacy of any of the disinfectant methods. Surprisingly, higher temperature enhanced the disinfecting efficacy of chlorine. However, higher temperature accelerated the decomposition of the chlorine residual such that an additional 120% volume of chlorine was required. All four methods proved efficacious in eradicating L. pneumophila from a model plumbing system

  13. Characterisation of Chlorine Behavior in French Graphite

    International Nuclear Information System (INIS)

    Blondel, A.; Moncoffre, N.; Toulhoat, N.; Bererd, N.; Petit, L.; Laurent, G.; Lamouroux, C.

    2016-01-01

    Chlorine 36 is one of the main radionuclides of concern for French graphite waste disposal. In order to help the understanding of its leaching behaviour under disposal conditions, the respective impact of temperature, irradiation and gas radiolysis on chlorine release in reactor has been studied. Chlorine 36 has been simulated through chlorine 37 ion implantation in virgin nuclear graphite samples. Results show that part of chlorine is highly mobile in graphite in the range of French reactors operating temperatures in relation with graphite structural recovering. Ballistic damage generated by irradiation also promotes chlorine release whereas no clear impact of the coolant gas radiolysis was observed in the absence of graphite radiolytic corrosion. (author)

  14. Effect of Chlorine Exposure on the Survival and Antibiotic Gene Expression of Multidrug Resistant Acinetobacter baumannii in Water

    Directory of Open Access Journals (Sweden)

    Deepti Prasad Karumathil

    2014-02-01

    Full Text Available Acinetobacter baumannii is a multidrug resistant pathogen capable of causing a wide spectrum of clinical conditions in humans. Acinetobacter spp. is ubiquitously found in different water sources. Chlorine being the most commonly used disinfectant in water, the study investigated the effect of chlorine on the survival of A. baumannii in water and transcription of genes conferring antibiotic resistance. Eight clinical isolates of A. baumannii, including a fatal meningitis isolate (ATCC 17978 (~108 CFU/mL were separately exposed to free chlorine concentrations (0.2, 1, 2, 3 and 4 ppm with a contact time of 30, 60, 90 and 120 second. The surviving pathogen counts at each specified contact time were determined using broth dilution assay. In addition, real-time quantitative PCR (RT-qPCR analysis of the antibiotic resistance genes (efflux pump genes and those encoding resistance to specific antibiotics of three selected A. baumannii strains following exposure to chlorine was performed. Results revealed that all eight A. baumannii isolates survived the tested chlorine levels during all exposure times (p > 0.05. Additionally, there was an up-regulation of all or some of the antibiotic resistance genes in A. baumannii, indicating a chlorine-associated induction of antibiotic resistance in the pathogen.

  15. Chlorine dioxide reaction with selected amino acids in water

    International Nuclear Information System (INIS)

    Navalon, Sergio; Alvaro, Mercedes; Garcia, Hermenegildo

    2009-01-01

    Chlorine dioxide is a hypochlorite alternative disinfectant agent. In this context, we have determined the products formed in the reaction of ClO 2 with selected amino acids as model compounds that can be present in natural waters. The reaction of tryptophane, histidine and tyrosine (10 ppm each) with ClO 2 were studied at molar ratios ranging from 0.25 to 4 in the presence or absence of oxygen. It was found that in the absence of oxygen adding substoichiometric amounts of ClO 2 creates products that are structurally similar to the starting amino acids. Through a series of cascade reactions the initial product distribution gradually evolves toward simple, small carbon chain products that are far from the starting amino acid. The reaction product distribution revealed that chlorine dioxide can attack the electron-rich aromatic moieties as well as the nitrogen atom lone electron pair. Our study is relevant to gain knowledge on the reaction mechanism of ClO 2 with ubiquitous amino acids present in natural waters.

  16. 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 ...

  17. Residual viral and bacterial contamination of surfaces after cleaning and disinfection.

    Science.gov (United States)

    Tuladhar, Era; Hazeleger, Wilma C; Koopmans, Marion; Zwietering, Marcel H; Beumer, Rijkelt R; Duizer, Erwin

    2012-11-01

    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, rotavirus, poliovirus, parechovirus, adenovirus, influenza virus, Staphylococcus aureus, and Salmonella enterica from artificially contaminated stainless steel surfaces. After a single wipe with water, liquid soap, or 250-ppm free chlorine solution, the numbers of infective viruses and bacteria were reduced by 1 log(10) for poliovirus and close to 4 log(10) for influenza virus. There was no significant difference in residual contamination levels after wiping with water, liquid soap, or 250-ppm chlorine solution. When a single wipe with liquid soap was followed by a second wipe using 250- or 1,000-ppm chlorine, an extra 1- to 3-log(10) reduction was achieved, and except for rotavirus and norovirus genogroup I, no significant additional effect of 1,000 ppm compared to 250 ppm was found. A reduced correlation between reduction in PCR units (PCRU) and reduction in infectious particles suggests that at least part of the reduction achieved in the second step is due to inactivation instead of removal alone. We used data on infectious doses and transfer efficiencies to estimate a target level to which the residual contamination should be reduced and found that a single wipe with liquid soap followed by a wipe with 250-ppm free chlorine solution was sufficient to reduce the residual contamination to below the target level for most of the pathogens tested.

  18. Endogenous Lunar Volatiles

    Science.gov (United States)

    McCubbin, F. M.; Liu, Y.; Barnes, J. J.; Boyce, J. W.; Day, J. M. D.; Elardo, S. M.; Hui, H.; Magna, T.; Ni, P.; Tartese, R.; hide

    2017-01-01

    The chapter will begin with an introduction that defines magmatic volatiles (e.g., H, F, Cl, S) versus geochemical volatiles (e.g., K, Rb, Zn). We will discuss our approach of understanding both types of volatiles in lunar samples and lay the ground work for how we will determine the overall volatile budget of the Moon. We will then discuss the importance of endogenous volatiles in shaping the "Newer Views of the Moon", specifically how endogenous volatiles feed forward into processes such as the origin of the Moon, magmatic differentiation, volcanism, and secondary processes during surface and crustal interactions. After the introduction, we will include a re-view/synthesis on the current state of 1) apatite compositions (volatile abundances and isotopic compositions); 2) nominally anhydrous mineral phases (moderately to highly volatile); 3) volatile (moderately to highly volatile) abundances in and isotopic compositions of lunar pyroclastic glass beads; 4) volatile (moderately to highly volatile) abundances in and isotopic compositions of lunar basalts; 5) volatile (moderately to highly volatile) abundances in and isotopic compositions of melt inclusions; and finally 6) experimental constraints on mineral-melt partitioning of moderately to highly volatile elements under lunar conditions. We anticipate that each section will summarize results since 2007 and focus on new results published since the 2015 Am Min review paper on lunar volatiles [9]. The next section will discuss how to use sample abundances of volatiles to understand the source region and potential caveats in estimating source abundances of volatiles. The following section will include our best estimates of volatile abundances and isotopic compositions (where permitted by available data) for each volatile element of interest in a number of important lunar reservoirs, including the crust, mantle, KREEP, and bulk Moon. The final section of the chapter will focus upon future work, outstanding questions

  19. Process for producing chlorinated polyethylene

    International Nuclear Information System (INIS)

    Nose, Shinji; Takayama, Shin-ichi; Kodama, Takashi.

    1970-01-01

    A process for chlorinated polyethylene by the chlorination of an aqueous suspension of polyethylene without the use catalysts is given, using 5-55% by gel content of cross-linked polyethylene powders. The products have favorable material workability, transparency, impact strength and tensile properties. In the case of peroxide cross-linking, a mixture of peroxides with polyethylene must be ground after heat treatment. The polyethylene may preferably have a gel content of 5-55%. The chlorination temperature may be 40 0 C or more, preferably 60 0 to 160 0 C. In one example, high pressure polymerized fine polyethylene powders of 15μ having a density of 0.935 g/cc, a softening point of 114 0 C, an average molecular weight of 35,000 were irradiated in air with 40 Mrad electron beams from a 2 MV Cockcroft-Walton type accelerator at room temperature. The thus irradiated polyethylene had a gel content of 55% and a softening point of 119 0 C. It was chlorinated upto a chlorine content of 33% at 100 0 C. Products were white crystals having a melting point of 122 0 C and a melting heat value of 32 mcal/mg. A sheet formed from this product showed a tensile strength of 280 kg/cm 2 , an elongation of 370% and a hardness of 90. (Iwakiri, K.)

  20. Evaluation of Handheld Assays for the Detection of Ricin and Staphylococcal Enterotoxin B in Disinfected Waters

    Directory of Open Access Journals (Sweden)

    Mary Margaret Wade

    2011-01-01

    Full Text Available Development of a rapid field test is needed capable of determining if field supplies of water are safe to drink by the warfighter during a military operation. The present study sought to assess the effectiveness of handheld assays (HHAs in detecting ricin and Staphylococcal Enterotoxin B (SEB in water. Performance of HHAs was evaluated in formulated tap water with and without chlorine, reverse osmosis water (RO with chlorine, and RO with bromine. Each matrix was prepared, spiked with ricin or SEB at multiple concentrations, and then loaded onto HHAs. HHAs were allowed to develop and then read visually. Limits of detection (LOD were determined for all HHAs in each water type. Both ricin and SEB were detected by HHAs in formulated tap water at or below the suggested health effect levels of 455 ng/mL and 4.55 ng/mL, respectively. However, in brominated or chlorinated waters, LODs for SEB increased to approximately 2,500 ng/mL. LODs for ricin increased in chlorinated water, but still remained below the suggested health effect level. In brominated water, the LOD for ricin increased to approximately 2,500 ng/mL. In conclusion, the HHAs tested were less effective at detecting ricin and SEB in disinfected water, as currently configured.

  1. Biodegradation of chlorinated ethenes by a methane-utilizing mixed culture

    International Nuclear Information System (INIS)

    Fogel, M.M.; Taddeo, A.R.; Fogel, S.

    1986-01-01

    Chlorinated ethenes are toxic substances which are widely distributed groundwater contaminants and are persistent in the subsurface environment. Reports on the biodegradation of these compounds under anaerobic conditions which might occur naturally in groundwater show that these substances degrade very slowly, if at all. Previous attempts to degrade chlorinated ethenes aerobically have produced conflicting results. A mixed culture containing methane-utilizing bacteria was obtained by methane enrichment of a sediment sample. Biodegradation experiments carried out in sealed culture bottles with radioactively labeled trichloroethylene (TCE) showed that approximately half of the radioactive carbon had been converted to 14 CO 2 and bacterial biomass. In addition to TCE, vinyl chloride and vinylidene chloride could be degraded to products which are not volatile chlorinated substances and are therefore likely to be further degraded to CO 2 . Two other chlorinated ethenes, cis and trans-1,2-dichloroethylene, were shown to degrade to chlorinated products, which appeared to degrade further. A sixth chlorinated ethene, tetrachloroethylene, was not degraded by the methane-utilizing culture under these conditions. The biodegradation of TCE was inhibited by acetylene, a specific inhibitor of methane oxidation by methanotrophs. This observation supported the hypothesis that a methanotroph is responsible for the observed biodegradations

  2. Recovery of actinides from actinide-aluminium alloys by chlorination: Part I

    Energy Technology Data Exchange (ETDEWEB)

    Cassayre, L., E-mail: cassayre@chimie.ups-tlse.fr [Laboratoire de Genie Chimique (LGC), Departement Procedes Electrochimiques, CNRS-UMR 5503, Universite de Toulouse III - Paul Sabatier, 31062 Toulouse (France); Soucek, P.; Mendes, E.; Malmbeck, R.; Nourry, C.; Eloirdi, R.; Glatz, J.-P. [European Commission, JRC, Institute for Transuranium Elements, Postfach 2340, 76125 Karlsruhe (Germany)

    2011-07-01

    Pyrochemical processes in molten LiCl-KCl are being developed in ITU for recovery of actinides from spent nuclear fuel. The fuel is anodically dissolved to the molten salt electrolyte and actinides are electrochemically reduced on solid aluminium cathodes forming solid actinide-aluminium alloys. A chlorination route is being investigated for recovery of actinides from the alloys. This route consists in three steps: Vacuum distillation for removal of the salt adhered on the electrode, chlorination of the actinide-aluminium alloys by chlorine gas and sublimation of the formed AlCl{sub 3}. A thermochemical study showed thermodynamic feasibility of all three steps. On the basis of the conditions identified by the calculations, experiments using pure UAl{sub 3} alloy were carried out to evaluate and optimise the chlorination step. The work was focused on determination of the optimal temperature and Cl{sub 2}/UAl{sub 3} molar ratio, providing complete chlorination of the alloy without formation of volatile UCl{sub 5} and UCl{sub 6}. The results showed high efficient chlorination at a temperature of 150 deg. C.

  3. Recovery of actinides from actinide-aluminium alloys by chlorination: Part I

    International Nuclear Information System (INIS)

    Cassayre, L.; Soucek, P.; Mendes, E.; Malmbeck, R.; Nourry, C.; Eloirdi, R.; Glatz, J.-P.

    2011-01-01

    Pyrochemical processes in molten LiCl-KCl are being developed in ITU for recovery of actinides from spent nuclear fuel. The fuel is anodically dissolved to the molten salt electrolyte and actinides are electrochemically reduced on solid aluminium cathodes forming solid actinide-aluminium alloys. A chlorination route is being investigated for recovery of actinides from the alloys. This route consists in three steps: Vacuum distillation for removal of the salt adhered on the electrode, chlorination of the actinide-aluminium alloys by chlorine gas and sublimation of the formed AlCl 3 . A thermochemical study showed thermodynamic feasibility of all three steps. On the basis of the conditions identified by the calculations, experiments using pure UAl 3 alloy were carried out to evaluate and optimise the chlorination step. The work was focused on determination of the optimal temperature and Cl 2 /UAl 3 molar ratio, providing complete chlorination of the alloy without formation of volatile UCl 5 and UCl 6 . The results showed high efficient chlorination at a temperature of 150 deg. C.

  4. Impact of bromide on halogen incorporation into organic moieties in chlorinated drinking water treatment and distribution systems.

    Science.gov (United States)

    Tan, J; Allard, S; Gruchlik, Y; McDonald, S; Joll, C A; Heitz, A

    2016-01-15

    The impact of elevated bromide concentrations (399 to 750 μg/L) on the formation of halogenated disinfection by-products (DBPs), namely trihalomethanes, haloacetic acids, haloacetonitriles, and adsorbable organic halogen (AOX), in two drinking water systems was investigated. Bromine was the main halogen incorporated into all of the DBP classes and into organic carbon, even though chlorine was present in large excess to maintain a disinfectant residual. Due to the higher reactivity of bromine compared to chlorine, brominated DBPs were rapidly formed, followed by a slower increase in chlorinated DBPs. Higher bromine substitution and incorporation factors for individual DBP classes were observed for the chlorinated water from the groundwater source (lower concentration of dissolved organic carbon (DOC)), which contained a higher concentration of bromide, than for the surface water source (higher DOC). The molar distribution of adsorbable organic bromine to chlorine (AOBr/AOCl) for AOX in the groundwater distribution system was 1.5:1 and almost 1:1 for the surface water system. The measured (regulated) DBPs only accounted for 16 to 33% of the total organic halogen, demonstrating that AOX measurements are essential to provide a full understanding of the formation of halogenated DBPs in drinking waters. In addition, the study demonstrated that a significant proportion (up to 94%) of the bromide in source waters can be converted AOBr. An evaluation of AOBr and AOCl through a second groundwater treatment plant that uses conventional treatment processes for DOC removal produced 70% of AOX as AOBr, with 69% of the initial source water bromide converted to AOBr. Exposure to organobromine compounds is suspected to result in greater adverse health consequences than their chlorinated analogues. Therefore, this study highlights the need for improved methods to selectively reduce the bromide content in source waters. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. 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.

  6. Occurrences of nitrosamines in chlorinated and chloraminated drinking water in three representative cities, China

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Qian; Wang, Donghong; Wang, Zijian

    2012-10-15

    An investigation of the occurrence of nine nitrosamines in drinking water following different water treatment processes was conducted using samples from seven drinking water treatment plants in three cities and tap waters in one city in China. The total nitrosamine levels ranged from not detected (n.d.) to 43.45 ng/L. The species and concentrations of the nine nitrosamines varied with disinfection methods and source waters. N-nitrosodimethylamine (NDMA), which is the nitrosamines of greatest concern, was identified in raw water, disinfecting water, finished water and tap water samples, ranging from 0.8 to 21.6, 0.12 to 24.2, n.d. to 8.8, and n.d. to 13.3 ng/L, respectively. Chloramination alone produced the most significant amounts of NDMA, while ozonation followed by chloramination led to moderately reduced levels. Additionally, chlorination produced relatively less NDMA, while low pressure ultraviolet radiation followed by chlorination could also significantly reduce them. Total organic carbon is one of the most important factors influencing nitrosamines formation in disinfecting water. In contrast, the addition of chlorine following any other disinfection was found to increase the formation of the other eight species of nitrosamines. The three nitrosamines recommended for monitoring by the US EPA were detected in the tap water samples, but most were present at levels below those that pose a risk to human health. Nevertheless, the occurrence and concentration of nitrosamines regulated in the Drinking Water Contaminant Candidate List could cause some potential human effects and therefore warrant attention. Highlights: Black-Right-Pointing-Pointer Nitrosamines in disinfected drinking water in three Chinese cities were investigated. Black-Right-Pointing-Pointer Some nitrosamines could be detected in raw water. Black-Right-Pointing-Pointer Advanced treatment affects nitrosamine levels both positively and negatively. Black-Right-Pointing-Pointer Organic matters

  7. Detection of chlorinated aromatic compounds

    Science.gov (United States)

    Ekechukwu, A.A.

    1996-02-06

    A method for making a composition for measuring the concentration of chlorinated aromatic compounds in aqueous fluids, and an optical probe for use with the method are disclosed. The composition comprises a hydrophobic polymer matrix, preferably polyamide, with a fluorescent indicator uniformly dispersed therein. The indicator fluoresces in the presence of the chlorinated aromatic compounds with an intensity dependent on the concentration of these compounds in the fluid of interest, such as 8-amino-2-naphthalene sulfonate. The probe includes a hollow cylindrical housing that contains the composition in its distal end. The probe admits an aqueous fluid to the probe interior for exposure to the composition. An optical fiber transmits excitation light from a remote source to the composition while the indicator reacts with chlorinated aromatic compounds present in the fluid. The resulting fluorescence light signal is reflected to a second optical fiber that transmits the light to a spectrophotometer for analysis. 5 figs.

  8. Benefits of carbon dioxide as pH reducer in chlorinated indoor swimming pools.

    Science.gov (United States)

    Gomà, Anton; Guisasola, Albert; Tayà, Carlota; Baeza, Juan A; Baeza, Mireia; Bartrolí, Albert; Lafuente, Javier; Bartrolí, Jordi

    2010-06-01

    Carbon dioxide is seldom used as pH reducer in swimming pools. Nevertheless it offers two interesting advantages. First, its use instead of the usual hydrochloric acid avoids the characteristic and serious accident of mixing the disinfectant with that strong acid, which forms a dangerous chlorine gas cloud and, second, it allows the facility to become slightly a depository of that greenhouse gas. This work introduces the experience of using CO(2) as pH reducer in real working swimming pools, showing three more advantages: lower chlorine consumption, lower presence of oxidants in the air above the swimming pool and a diminished formation of trihalomethanes in the swimming pool water. Experiments lasted 4years and they were run in three swimming pools in the Barcelona area, where the conventional system based upon HCl and a system based upon CO(2) were consecutively exchanged.

  9. Bacterial community changes in copper and PEX drinking water pipeline biofilms under extra disinfection and magnetic water treatment.

    Science.gov (United States)

    Inkinen, J; Jayaprakash, B; Ahonen, M; Pitkänen, T; Mäkinen, R; Pursiainen, A; Santo Domingo, J W; Salonen, H; Elk, M; Keinänen-Toivola, M M

    2018-02-01

    To study the stability of biofilms and water quality in pilot scale drinking water copper and PEX pipes in changing conditions (extra disinfection, magnetic water treatment, MWT). Next-generation sequencing (NGS) of 16S ribosomal RNA genes (rDNA) to describe total bacterial community and ribosomal RNA (rRNA) to describe active bacterial members in addition to traditional microbiological methods were applied. Biofilms from control copper and PEX pipes shared same most abundant bacteria (Methylobacterium spp., Sphingomonas spp., Zymomonas spp.) and average species diversities (Shannon 3·8-4·2) in rDNA and rRNA libraries, whereas few of the taxa differed by their abundance such as lower total Mycobacterium spp. occurrence in copper (disinfection (total chlorine increase from c. 0·5 to 1 mg l -1 ) affected total and active population in biofilms seen as decrease in many bacterial species and diversity (Shannon 2·7, P disinfected copper and PEX samples formed separate clusters in unweighted non-metric multidimensional scaling plot (rRNA) similarly to MWT-treated biofilms of copper (but not PEX) pipes that instead showed higher species diversity (Shannon 4·8, P < 0·05 interaction). Minor chlorine dose addition increased selection pressure and many species were sensitive to chlorination. Pipe material seemed to affect mycobacteria occurrence, and bacterial communities with MWT in copper but not in PEX pipes. This study using rRNA showed that chlorination affects especially active fraction of bacterial communities. Copper and PEX differed by the occurrence of some bacterial members despite similar community profiles. © 2017 The Society for Applied Microbiology.

  10. Kinetics of molybdenum and chlorine interaction

    International Nuclear Information System (INIS)

    Zelikman, A.N.; Nazarov, Yu.N.; Sarkarov, T.Eh.; Tulyakov, N.V.

    1977-01-01

    The kinetics is studied of molybdenite chlorination with gaseous chlorine. The time dependences of the depth and degree of molybdenite chlorination are given along with the dependence on chlorine concentration of molybdenite chlorination rate. Active interaction is shown to take place at 450-470 deg C. At 350-435 deg C, chlorination occurs in the kinetic range, the apparent activation energy being equal to 22.2 kcal/mole and the order of reaction by chlorine to 0.77. At 435-610 deg C, the process takes place in the diffusion range and is restricted by dissipation of the reaction products (activation energy - 4.05 kcal/mole; order of reaction by chlorine - 0.6)

  11. A comparative study of disinfection efficiency and regrowth control of microorganism in secondary wastewater effluent using UV, ozone, and ionizing irradiation process

    Energy Technology Data Exchange (ETDEWEB)

    Lee, O-Mi [Quarantine Technology Center, Animal and Plant Quarantine Agency Plant, 175 Anyangro, Manan-Gu, Anyang-Si, Gyeonggi-Do 480-757 (Korea, Republic of); Kim, Hyun Young; Park, Wooshin; Kim, Tae-Hun [Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, 29 Geumgu-gil, Jeongeup, Jeonbuk 580-185 (Korea, Republic of); Yu, Seungho, E-mail: seunghoyu68@gmail.com [Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, 29 Geumgu-gil, Jeongeup, Jeonbuk 580-185 (Korea, Republic of)

    2015-09-15

    Highlights: • The ionizing radiation was applied to inactivate microorganisms and the critical dose to prevent the regrowth was determined. • The seasonal variation of disinfection efficiency observed in on-site UV treatment system was influenced by suspended solid, temperature, and precipitation, whereas, stable values were observed in ionizing radiation. • The electrical power consumption for disinfection using UV and ozone requires higher energy than ionizing radiation. - Abstract: Ionizing radiation technology was suggested as an alternative method to disinfection processes, such as chlorine, UV, and ozone. Although many studies have demonstrated the effectiveness of irradiation technology for microbial disinfection, there has been a lack of information on comparison studies of disinfection techniques and a regrowth of each treatment. In the present study, an ionizing radiation was investigated to inactivate microorganisms and to determine the critical dose to prevent the regrowth. As a result, it was observed that the disinfection efficiency using ionizing radiation was not affected by the seasonal changes of wastewater characteristics, such as temperature and turbidity. In terms of bacterial regrowth after disinfection, the ionizing radiation showed a significant resistance of regrowth, whereas, on-site UV treatment is influenced by the suspended solid, temperature, or precipitation. The electric power consumption was also compared for the economic feasibility of each technique at a given value of disinfection efficiency of 90% (1-log), showing 0.12, 36.80, and 96.53 Wh/(L/day) for ionizing radiation, ozone, and UV, respectively. The ionizing radiation requires two or three orders of magnitude lower power consumption than UV and ozone. Consequently, ionizing radiation can be applied as an effective and economical alternative technique to other conventional disinfection processes.

  12. A comparative study of disinfection efficiency and regrowth control of microorganism in secondary wastewater effluent using UV, ozone, and ionizing irradiation process

    International Nuclear Information System (INIS)

    Lee, O-Mi; Kim, Hyun Young; Park, Wooshin; Kim, Tae-Hun; Yu, Seungho

    2015-01-01

    Highlights: • The ionizing radiation was applied to inactivate microorganisms and the critical dose to prevent the regrowth was determined. • The seasonal variation of disinfection efficiency observed in on-site UV treatment system was influenced by suspended solid, temperature, and precipitation, whereas, stable values were observed in ionizing radiation. • The electrical power consumption for disinfection using UV and ozone requires higher energy than ionizing radiation. - Abstract: Ionizing radiation technology was suggested as an alternative method to disinfection processes, such as chlorine, UV, and ozone. Although many studies have demonstrated the effectiveness of irradiation technology for microbial disinfection, there has been a lack of information on comparison studies of disinfection techniques and a regrowth of each treatment. In the present study, an ionizing radiation was investigated to inactivate microorganisms and to determine the critical dose to prevent the regrowth. As a result, it was observed that the disinfection efficiency using ionizing radiation was not affected by the seasonal changes of wastewater characteristics, such as temperature and turbidity. In terms of bacterial regrowth after disinfection, the ionizing radiation showed a significant resistance of regrowth, whereas, on-site UV treatment is influenced by the suspended solid, temperature, or precipitation. The electric power consumption was also compared for the economic feasibility of each technique at a given value of disinfection efficiency of 90% (1-log), showing 0.12, 36.80, and 96.53 Wh/(L/day) for ionizing radiation, ozone, and UV, respectively. The ionizing radiation requires two or three orders of magnitude lower power consumption than UV and ozone. Consequently, ionizing radiation can be applied as an effective and economical alternative technique to other conventional disinfection processes

  13. Formation of aryl-chlorinated aromatic acids and precursors for chloroform in chlorination of humic acid

    NARCIS (Netherlands)

    Sinninghe Damsté, J.S.; Leer, E.W.B. de; Galan, L.

    1985-01-01

    The formation of chloroform when humic substances are chlorinated is well known. Other chlorinated products that may be formed are chloral, di- and trichloroacetic acid, chlorinated C-4 diacids, and α-chlorinated aliphatic acids. Several of these compounds are formed in molar yields comparable

  14. Asymmetric Realized Volatility Risk

    Directory of Open Access Journals (Sweden)

    David E. Allen

    2014-06-01

    Full Text Available In this paper, we document that realized variation measures constructed from high-frequency returns reveal a large degree of volatility risk in stock and index returns, where we characterize volatility risk by the extent to which forecasting errors in realized volatility are substantive. Even though returns standardized by ex post quadratic variation measures are nearly Gaussian, this unpredictability brings considerably more uncertainty to the empirically relevant ex ante distribution of returns. Explicitly modeling this volatility risk is fundamental. We propose a dually asymmetric realized volatility model, which incorporates the fact that realized volatility series are systematically more volatile in high volatility periods. Returns in this framework display time varying volatility, skewness and kurtosis. We provide a detailed account of the empirical advantages of the model using data on the S&P 500 index and eight other indexes and stocks.

  15. Direct Chlorination of Zircon Sand

    International Nuclear Information System (INIS)

    Dwiretnani Sudjoko; Budi Sulistyo; Pristi Hartati; Sunardjo

    2002-01-01

    It was investigated the direct chlorination of zircon sand in a unit chlorination equipment. The process was in semi batch. The product gas was scrubbed in aqueous NaOH. It was search the influence of time, ratio of reactant and size of particle sand to the concentration of Zr and Si in the product. From these research it was found that as the times, ratio of reactant increased, the concentration of Zr increased, but the concentration of Si decreased, while as grain size of zircon sand decreased the concentration of Zr decreased, but the concentration of Si increased. (author)

  16. 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.

  17. Transformation of Flame Retardant Tetrabromobisphenol A by Aqueous Chlorine and the Effect of Humic Acid.

    Science.gov (United States)

    Gao, Yuan; Pang, Su-Yan; Jiang, Jin; Ma, Jun; Zhou, Yang; Li, Juan; Wang, Li-Hong; Lu, Xue-Ting; Yuan, Li-Peng

    2016-09-06

    In this work, it was found that the most widely used brominated flame retardant tetrabromobisphenol A (TBrBPA) could be transformed by free chlorine over a wide pH range from 5 to 10 with apparent second-order rate constants from 138 to 3210 M(-1)·s(-1). A total of eight products, including one quinone-like compound (i.e., 2,6-dibromoquinone), two dimers, and several simple halogenated phenols (e.g., 4-(2-hydroxyisopropyl)-2,6-dibromophenol, 2,6-dibromohydroquinone, and 2,4,6-tribromophenol), were detected by high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) using a novel precursor ion scan (PIS) approach. A tentative reaction pathway was proposed: chlorine initially oxidized TBrBPA leading to the formation of a phenoxy radical, and then this primary radical and its secondary intermediates (e.g., 2,6-dibromo-4-isopropylphenol carbocation) formed via beta-scission subsequently underwent substitution, dimerization, and oxidation reactions. Humic acid (HA) considerably inhibited the degradation rates of TBrBPA by chlorine even accounting for oxidant consumption. A similar inhibitory effect of HA was also observed in permanganate and ferrate oxidation. This inhibitory effect was possibly attributed to the fact that HA competitively reacted with the phenoxy radical of TBrBPA and reversed it back to parent TBrBPA. This study confirms that chlorine can transform phenolic compounds (e.g., TBrBPA) via electron transfer rather than the well-documented electrophilic substitution, which also have implications on the formation pathway of halo-benzoquinones during chlorine disinfection. These findings can improve the understanding of chlorine chemistry in water and wastewater treatment.

  18. Removal of Intermediate Aromatic Halogenated DBPs by Activated Carbon Adsorption: A New Approach to Controlling Halogenated DBPs in Chlorinated Drinking Water.

    Science.gov (United States)

    Jiang, Jingyi; Zhang, Xiangru; Zhu, Xiaohu; Li, Yu

    2017-03-21

    During chlorine disinfection of drinking water, chlorine may react with natural organic matter (NOM) and bromide ion in raw water to generate halogenated disinfection byproducts (DBPs). To mitigate adverse effects from DBP exposure, granular activated carbon (GAC) adsorption has been considered as one of the best available technologies for removing NOM (DBP precursor) in drinking water treatment. Recently, we have found that many aromatic halogenated DBPs form in chlorination, and they act as intermediate DBPs to decompose and form commonly known DBPs including trihalomethanes and haloacetic acids. In this work, we proposed a new approach to controlling drinking water halogenated DBPs by GAC adsorption of intermediate aromatic halogenated DBPs during chlorination, rather than by GAC adsorption of NOM prior to chlorination (i.e., traditional approach). Rapid small-scale column tests were used to simulate GAC adsorption in the new and traditional approaches. Significant reductions of aromatic halogenated DBPs were observed in the effluents with the new approach; the removals of total organic halogen, trihalomethanes, and haloacetic acids by the new approach always exceeded those by the traditional approach; and the effluents with the new approach were considerably less developmentally toxic than those with the traditional approach. Our findings indicate that the new approach is substantially more effective in controlling halogenated DBPs than the traditional approach.

  19. Influence of Nitrogen Source on NDMA Formation during Chlorination of Diuron

    Science.gov (United States)

    Chen, Wei-Hsiang; Young, Thomas M.

    2009-01-01

    N-Nitrosodimethylamine (NDMA) is formed during chlorination of water containing the herbicide diuron (N′-(3,4-dichlorophenyl)-N, N-dimethylurea) but formation is greatly enhanced in the presence of ammonia (chloramination). Groundwater impacted by agricultural runoff may contain diuron and relatively high total nitrogen concentrations; this study examines the impact of the nitrogen form (ammonium, nitrite or nitrate) on NDMA formation during chlorination of such waters. NDMA formation during chlorination of diuron increased in the order nitrite diuron dose. Formation of dichloramine seemed to fully explain enhanced NDMA formation in the presence of ammonium. Nitrate unexpectedly enhanced nitrosation of diuron derivatives to form NDMA compared to the cases of no added nitrogen or nitrite addition. Nitrite addition is less effective because it consumes more chlorine and produces intermediates that react rapidly with diuron and its aromatic byproducts. Differences between surface and groundwater in nitrogen forms and concentrations and disinfection approaches, suggest strategies to reduce NDMA formation should vary with drinking water source. PMID:19457535

  20. Analytical and experimental investigation of chlorine decay in water supply systems under unsteady hydraulic conditions

    DEFF Research Database (Denmark)

    Aisopou, Angeliki; Stoianov, Ivan; Graham, Nigel

    2013-01-01

    This paper investigates the impact of the dynamic hydraulic conditions on the kinetics of chlorine decay in water supply systems. A simulation framework has been developed for the scale-adaptive hydraulic and chlorine decay modelling under steady- and unsteady-state flows. An unsteady decay coeff...... of experimental data provides new insights for the near real-time modelling and management of water quality as well as highlighting the uncertainty and challenges of accurately modelling the loss of disinfectant in water supply networks.......This paper investigates the impact of the dynamic hydraulic conditions on the kinetics of chlorine decay in water supply systems. A simulation framework has been developed for the scale-adaptive hydraulic and chlorine decay modelling under steady- and unsteady-state flows. An unsteady decay...... coefficient is defined which depends upon the absolute value of shear stress and the rate of change of shear stress for quasi-unsteady and unsteady-state flows. By coupling novel instrumentation technologies for continuous hydraulic monitoring and water quality sensors for in-pipe water quality sensing...

  1. Effects of electrode settings on chlorine generation efficiency of electrolyzing seawater.

    Science.gov (United States)

    Hsu, Guoo-Shyng Wang; Hsia, Chih-Wei; Hsu, Shun-Yao

    2015-12-01

    Electrolyzed water has significant disinfection effects, can comply with food safety regulations, and is environmental friendly. We investigated the effects of immersion depth of electrodes, stirring, electrode size, and electrode gap on the properties and chlorine generation efficiency of electrolyzing seawater and its storage stability. Results indicated that temperature and oxidation-reduction potential (ORP) of the seawater increased gradually, whereas electrical conductivity decreased steadily in electrolysis. During the electrolysis process, pH values and electric currents also decreased slightly within small ranges. Additional stirring or immersing the electrodes deep under the seawater significantly increased current density without affecting its electric efficiency and current efficiency. Decreasing electrode size or increasing electrode gap decreased chlorine production and electric current of the process without affecting its electric efficiency and current efficiency. Less than 35% of chlorine in the electrolyzed seawater was lost in a 3-week storage period. The decrement trend leveled off after the 1 st week of storage. The electrolyzing system is a convenient and economical method for producing high-chlorine seawater, which will have high potential applications in agriculture, aquaculture, or food processing. Copyright © 2015. Published by Elsevier B.V.

  2. Effects of electrode settings on chlorine generation efficiency of electrolyzing seawater

    Directory of Open Access Journals (Sweden)

    Guoo-Shyng Wang Hsu

    2015-12-01

    Full Text Available Electrolyzed water has significant disinfection effects, can comply with food safety regulations, and is environmental friendly. We investigated the effects of immersion depth of electrodes, stirring, electrode size, and electrode gap on the properties and chlorine generation efficiency of electrolyzing seawater and its storage stability. Results indicated that temperature and oxidation-reduction potential (ORP of the seawater increased gradually, whereas electrical conductivity decreased steadily in electrolysis. During the electrolysis process, pH values and electric currents also decreased slightly within small ranges. Additional stirring or immersing the electrodes deep under the seawater significantly increased current density without affecting its electric efficiency and current efficiency. Decreasing electrode size or increasing electrode gap decreased chlorine production and electric current of the process without affecting its electric efficiency and current efficiency. Less than 35% of chlorine in the electrolyzed seawater was lost in a 3-week storage period. The decrement trend leveled off after the 1st week of storage. The electrolyzing system is a convenient and economical method for producing high-chlorine seawater, which will have high potential applications in agriculture, aquaculture, or food processing.

  3. Examining the interrelationship between DOC, bromide and chlorine dose on DBP formation in drinking water--a case study.

    Science.gov (United States)

    Bond, Tom; Huang, Jin; Graham, Nigel J D; Templeton, Michael R

    2014-02-01

    During drinking water treatment aqueous chlorine and bromine compete to react with natural organic matter (NOM). Among the products of these reactions are potentially harmful halogenated disinfection by-products, notably four trihalomethanes (THM4) and nine haloacetic acids (HAAs). Previous research has concentrated on the role of bromide in chlorination reactions under conditions of a given NOM type and/or concentration. In this study different concentrations of dissolved organic carbon (DOC) from U.K. lowland water were reacted with varying amounts of bromide and chlorine in order to examine the interrelationship between the three reactants in the formation of THM4, dihaloacetic acids (DHAAs) and trihaloacetic acids (THAAs). Results showed that, in general, molar yields of THM4 increased with DOC, bromide and chlorine concentrations, although yields did fluctuate versus chlorine dose. In contrast both DHAA and THAA yields were mainly independent of changes in bromide and chlorine dose at low DOC (1 mg·L(-1)), but increased with chlorine dose at higher DOC concentrations (4 mg·L(-1)). Bromine substitution factors reached maxima of 0.80, 0.67 and 0.65 for the THM4, DHAAs and THAAs, respectively, at the highest bromide/chlorine ratio studied. These results suggest that THM4 formation kinetics depend on both oxidation and halogenation steps, whereas for DHAAs and THAAs oxidation steps are more important. Furthermore, they indicate that high bromide waters may prove more problematic for water utilities with respect to THM4 formation than for THAAs or DHAAs. While mass concentrations of all three groups increased in response to increased bromide incorporation, only the THMs also showed an increase in molar yield. Overall, the formation behaviour of DHAA and THAA was more similar than that of THM4 and THAA. © 2013.

  4. The effect of various disinfectants on detection of avian influenza virus by real time RT-PCR.

    Science.gov (United States)

    Suarez, D L; Spackman, E; Senne, D A; Bulaga, L; Welsch, A C; Froberg, K

    2003-01-01

    -PCR. The peroxygen and chlorine compounds were effective at some concentrations for both inactivating virus and preventing amplification by RRT-PCR. Therefore, the RRT-PCR test can potentially be used to assure proper cleaning and disinfection when certain disinfectants are used.

  5. 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.

  6. Evaluating the Sporicidal Activity of Disinfectants against Clostridium difficile and Bacillus amyloliquefaciens Spores by Using the Improved Methods Based on ASTM E2197-11.

    Science.gov (United States)

    Uwamahoro, Marie Christine; Massicotte, Richard; Hurtubise, Yves; Gagné-Bourque, François; Mafu, Akier Assanta; Yahia, L'Hocine

    2018-01-01

    Spore-forming pathogenic bacteria, such as Clostridium difficile , are associated with nosocomial infection, leading to the increased use of sporicidal disinfectants, which impacts socioeconomic costs. However, C. difficile can be prevented using microorganisms such as Bacillus amyloliquefaciens , a prophylactic agent that has been proven to be effective against it in recent tests or it can be controlled by sporicidal disinfectants. These disinfectants against spores should be evaluated according to a known and recommended standard. Unfortunately, some newly manufactured disinfectants like Bioxy products have not yet been tested. ASTM E2197-11 is a standard test that uses stainless steel disks (1 cm in diameter) as carriers, and the performance of the test formulation is calculated by comparing the number of viable test organisms to that on the control carriers. Surface tests are preferable for evaluating disinfectants with sporicidal effects on hard surfaces. This study applies improved methods, based on the ASTM E2197-11 standard, for evaluating and comparing the sporicidal efficacies of several disinfectants against spores of C. difficile and B. amyloliquefaciens , which are used as the test organisms. With the improved method, all spores were recovered through vortexing and membrane filtration. The results show that chlorine-based products are effective in 5 min and Bioxy products at 5% w/v are effective in 10 min. Although Bioxy products may take longer to prove their effectiveness, their non-harmful effects to hospital surfaces and people have been well established in the literature.

  7. 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

  8. Detection of chlorine in water

    Czech Academy of Sciences Publication Activity Database

    Kašík, Ivan; Mrázek, Jan; Podrazký, Ondřej; Seidl, Miroslav; Aubrecht, Jan; Tobiška, Petr; Pospíšilová, Marie; Matějec, Vlastimil; Kovács, B.; Markovics, A.; Szili, M.

    2009-01-01

    Roč. 139, č. 1 (2009), s. 139-142 ISSN 0925-4005 R&D Projects: GA MŠk(CZ) LC06034; GA ČR(CZ) GA102/05/0948 Institutional research plan: CEZ:AV0Z20670512 Keywords : optical fiber sensor * chlorine Subject RIV: JB - Sensors, Measurment, Regulation Impact factor: 3.083, year: 2009

  9. 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

  10. 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...

  11. 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.

  12. 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

  13. Endogenous Lunar Volatiles

    Science.gov (United States)

    McCubbin, F. M.; Liu, Y.; Barnes, J. J.; Anand, M.; Boyce, J. W.; Burney, D.; Day, J. M. D.; Elardo, S. M.; Hui, H.; Klima, R. L.; Magna, T.; Ni, P.; Steenstra, E.; Tartèse, R.; Vander Kaaden, K. E.

    2018-04-01

    This abstract discusses numerous outstanding questions on the topic of endogenous lunar volatiles that will need to be addressed in the coming years. Although substantial insights into endogenous lunar volatiles have been gained, more work remains.

  14. 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.

  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. Fitness and Recovery of Bacterial Communities and Antibiotic Resistance Genes in Urban Wastewaters Exposed to Classical Disinfection Treatments.

    Science.gov (United States)

    Di Cesare, Andrea; Fontaneto, Diego; Doppelbauer, Julia; Corno, Gianluca

    2016-09-20

    Antibiotic resistance genes (ARGs) are increasingly appreciated to be important as micropollutants. Indirectly produced by human activities, they are released into the environment, as they are untargeted by conventional wastewater treatments. In order to understand the fate of ARGs and of other resistant forms (e.g., phenotypical adaptations) in urban wastewater treatment plants (WWTPs), we monitored three WWTPs with different disinfection processes (chlorine, peracetic acid (PAA), and ultraviolet light (UV)). We monitored WWTPs influx and pre- and postdisinfection effluent over 24 h, followed by incubation experiments lasting for 96 h. We measured bacterial abundance, size distribution and aggregational behavior, the proportion of intact (active) cells, and the abundances of four ARGs and of the mobile element integron1. While all the predisinfection treatments of all WWTPs removed the majority of bacteria and of associated ARGs, of the disinfection processes only PAA efficiently removed bacterial cells. However, the stress imposed by PAA selected for bacterial aggregates and, similarly to chlorine, stimulated the selection of ARGs during the incubation experiment. This suggests disinfections based on chemically aggressive destruction of bacterial cell structures can promote a residual microbial community that is more resistant to antibiotics and, given the altered aggregational behavior, to competitive stress in nature.

  17. Nonvolatile, semivolatile, or volatile: redefining volatile for volatile organic compounds.

    Science.gov (United States)

    Võ, Uyên-Uyén T; Morris, Michael P

    2014-06-01

    Although widely used in air quality regulatory frameworks, the term "volatile organic compound" (VOC) is poorly defined. Numerous standardized tests are currently used in regulations to determine VOC content (and thus volatility), but in many cases the tests do not agree with each other, nor do they always accurately represent actual evaporation rates under ambient conditions. The parameters (time, temperature, reference material, column polarity, etc.) used in the definitions and the associated test methods were created without a significant evaluation of volatilization characteristics in real world settings. Not only do these differences lead to varying VOC content results, but occasionally they conflict with one another. An ambient evaporation study of selected compounds and a few formulated products was conducted and the results were compared to several current VOC test methodologies: SCAQMD Method 313 (M313), ASTM Standard Test Method E 1868-10 (E1868), and US. EPA Reference Method 24 (M24). The ambient evaporation study showed a definite distinction between nonvolatile, semivolatile, and volatile compounds. Some low vapor pressure (LVP) solvents, currently considered exempt as VOCs by some methods, volatilize at ambient conditions nearly as rapidly as the traditional high-volatility solvents they are meant to replace. Conversely, bio-based and heavy hydrocarbons did not readily volatilize, though they often are calculated as VOCs in some traditional test methods. The study suggests that regulatory standards should be reevaluated to more accurately reflect real-world emission from the use of VOC containing products. The definition of VOC in current test methods may lead to regulations that exclude otherwise viable alternatives or allow substitutions of chemicals that may limit the environmental benefits sought in the regulation. A study was conducted to examine volatility of several compounds and a few formulated products under several current VOC test

  18. Normalization for Implied Volatility

    OpenAIRE

    Fukasawa, Masaaki

    2010-01-01

    We study specific nonlinear transformations of the Black-Scholes implied volatility to show remarkable properties of the volatility surface. Model-free bounds on the implied volatility skew are given. Pricing formulas for the European options which are written in terms of the implied volatility are given. In particular, we prove elegant formulas for the fair strikes of the variance swap and the gamma swap.

  19. Realized Volatility Risk

    NARCIS (Netherlands)

    D.E. Allen (David); M.J. McAleer (Michael); M. Scharth (Marcel)

    2013-01-01

    textabstractIn this paper we document that realized variation measures constructed from highfrequency returns reveal a large degree of volatility risk in stock and index returns, where we characterize volatility risk by the extent to which forecasting errors in realized volatility are substantive.

  20. Disinfection of wastewater by hydrogen peroxide or peracetic acid: development of procedures for measurement of residual disinfectant and application to a physicochemically treated municipal effluent.

    Science.gov (United States)

    Wagner, Monika; Brumelis, Daina; Gehr, Ronald

    2002-01-01

    The Montreal Urban Community Wastewater Treatment Plant (MUCWTP) located in Montreal. Quebec, Canada, uses physicochemical treatment processes prior to discharging wastewater into the St. Lawrence River via an outfall tunnel of 2 hours retention time. Although chlorination facilities exist, they are not being used, and the MUCWTP is seeking alternative methods for disinfection to achieve a 2- to 3-log fecal coliform reduction. Liquid chemical disinfectants were attractive options because of their low capital costs. This led to an investigation of the feasibility of using hydrogen peroxide or peracetic acid. A method for measuring peroxycompounds (hydrogen peroxide or peracetic acid plus hydrogen peroxide) was developed using the peroxidase-based oxidation of 2,2'-azino-bis(3-ethylbenz-thiazoline-6-sulfuric acid) diammonium salt (ABTS) with hydrogen peroxide. The validity of the method was confirmed using effluent from the MUCWTP. Recovery was higher than 90% for peracetic acid levels as low as 1.0 mg/L. Quenching of hydrogen peroxide was achieved with 50-mg/L catalase; quenching of peracetic acid was achieved with 100 mg/L of sodium thiosulfate, followed by 50 mg/L of catalase. Batch disinfection tests were conducted on MUCWTP effluent. Hydrogen peroxide and peracetic acid in wastewater over time could be modeled as a second-order decay, with the decay "constant" being a function of the initial concentration of peroxycompounds. This function was the same for both hydrogen peroxide and peracetic acid, possibly indicating similar decomposition pathways in wastewater matrices. Disinfection was modeled using a modified Hom equation. Required doses of hydrogen peroxide to reach the target fecal coliform levels ranged from 106 to 285 mg/L, with the higher doses occurring when ferric chloride instead of alum was used as the coagulant. Hence, hydrogen peroxide was infeasible as a disinfectant for this application. On the other hand, the peracetic acid dose needed to

  1. Ozone Disinfection of Vibrio vulnificus in Shrimp Pond Water

    Science.gov (United States)

    Dyah Pita Rengga, Wara; Cahya Julyta Putri, Echa; Wulansarie, Ria; Suryanto, Agus

    2018-03-01

    One variety of shrimp, L.Vanamei, often uses brackish water during the operation in the shrimp pond. Chlorination and ultraviolet are usually used for disinfection of brackish water. However, it is ineffective and forms sediment in the water distribution. It can be a negative impact on the water quality cause a contamination on the shrimp, so the farmers might have loss of profit because Vibrio vulnificus causes infection and dead on the shrimp. It affects the safety of consumers and should be minimized. The purpose of this study is to reduce the number of V. vulnificus bacteria in the pond water. The water was put in the storage tanks then pumped to filter out the impurities of the water. Furthermore, the water set the flow rate in 1 LPM, 2 LPM, and 3 LPM. After that, the ozone was injected to the water flow to sterilize the V. vulnificus bacteria. Finally, the water was returned to the original tank. The water from the tank was taken through a valve and analyzed in 0, 3, 7, 12, 18, 24, 30 minutes. The sample was analyzed immediately using a Total Plate Count method to determine the number of V. vulnificus bacteria in the shrimp pond water. The flow rate shows that the longer time of ozone made a lower amount of Vibrio v. bacteria. In 2 LPM water, it shows the optimum results of V. vulnificus. bacteria reduction for 88.1% compared to the flow rate of 1 LPM and 3 LPM with the bacteria reduction of 68,8% and 70.6%. This study shows that the ozone with a flow rate of 2 LPM circulation is the most effective method to help reducing the number of V. vulnificus in brackish water distribution system in the shrimp environment and potentially as a disinfectant.

  2. METHOD OF SEPARATING URANIUM VALUES, PLUTONIUM VALUES AND FISSION PRODUCTS BY CHLORINATION

    Science.gov (United States)

    Brown, H.S.; Seaborg, G.T.

    1959-02-24

    The separation of plutonium and uranium from each other and from other substances is described. In general, the method comprises the steps of contacting the uranium with chlorine in the presence of a holdback material selected from the group consisting of lanthanum oxide and thorium oxide to form a uranium chloride higher than uranium tetrachloride, and thereafter heating the uranium chloride thus formed to a temperature at which the uranium chloride is volatilized off but below the volatilizalion temperature of plutonium chloride.

  3. 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

  4. Production of T-2 toxin and deoxynivalenol in the presence of different disinfectants

    Directory of Open Access Journals (Sweden)

    Dana Hrubošová

    2015-03-01

    Full Text Available The aim of the work was to examine the effect of different disinfectants on production trichothecenes (especially of T-2 toxin and deoxynivalenol. Lipophilicity, chemical structure, the presence of bioactive groups and functional groups in their structure modifies biological activity and toxic potency of trichothecenes. For this reason, limits have been established designating maximum levels of mycotoxins in cereals while maintaining proper growing practices. Appropriate nutritive media were prepared with different concentration of tested disinfectants (Desanal A  plus, ProCura spray and Guaa-Pool and were inoculated using  Fusarium strains. The density of  Fusarium was 105 spores per mililitre. Nutrient media was cultivated at 15 °C and 25 °C for seven days. The strains of Fusarium graminearum CCM F-683 and Fusarium species (isolated from barley produced quantities of deoxynivalenol. Fusarium poae CCM F-584 and Fusarium species (isolated from malthouse air produced quantities of T-2 toxin. Desanal A plus prevented Fusarium growth and production of T-2 toxin and deoxynivalenol at the concentration 10%. It is an alkaline disinfectant on the basis of active chlorine and the surfactant that contains ˂5% of NaClO. ProCura spray at the concentration 0.6% proved to be very effective. This disinfectant contains 35% of propan-1-ol and 25% of propan-2-ol.  Guaa-Pool at the concentration 0.004% proved to be very effective. It is a polymeric disinfectant with anion surface-acting agent and it contains ˂0.9% of polyhexamethylene guanidine hydrochloride and ˂0.2% of alkyl (C12-C16 dimethylbenzyl ammonium chloride. Lower contentration of  disinfectants that  not prevented growth of Fusarium caused higher production  of T-2 toxin and deoxynivalenol. The contents of T-2 toxin and deoxynivalenol were analyzed by enzyme-linked immunosorbent assay (ELISA using commercially produced kits (Agra Quant® Deoxynivalenol Test kit and Agra Quant® T-2 toxin

  5. 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.

  6. 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.

  7. Chlorination Revisited: Does Cl- Serve as a Catalyst in the Chlorination of Phenols?

    Science.gov (United States)

    Lau, Stephanie S; Abraham, Sonali M; Roberts, A Lynn

    2016-12-20

    The aqueous chlorination of (chloro)phenols is one of the best-studied reactions in the environmental literature. Previous researchers have attributed these reactions to two chlorine species: HOCl (at circum-neutral and high pH) and H 2 OCl + (at low pH). In this study, we seek to examine the roles that two largely overlooked chlorine species, Cl 2 and Cl 2 O, may play in the chlorination of (chloro)phenols. Solution pH, chloride concentration, and chlorine dose were systematically varied in order to assess the importance of different chlorine species as chlorinating agents. Our findings indicate that chlorination rates at pH pH 6.0 and a chlorine dose representative of drinking water treatment, Cl 2 O is predicted to have at best a minor impact on chlorination reactions, whereas Cl 2 may contribute more than 80% to the overall chlorination rate depending on the (chloro)phenol identity and chloride concentration. While it is not possible to preclude H 2 OCl + as a chlorinating agent, we were able to model our low-pH data by considering Cl 2 only. Even traces of chloride can generate sufficient Cl 2 to influence chlorination kinetics, highlighting the role of chloride as a catalyst in chlorination reactions.

  8. Endogenous Lunar Volatiles: Insights into the Abundances of Volatiles in the Moon from Lunar Apatite

    Science.gov (United States)

    McCubbin, Francis

    2016-01-01

    At the time of publication of New Views of the Moon, it was thought that the Moon was bone dry with less than about 1 ppb H2O. However in 2007, initial reports at the 38th Lunar and Planetary Science Conference speculated that H-species were present in both apatites and pyroclastic volcanic lunar glasses. These early reports were later confirmed through peer-review, which motivated many subsequent studies on magmatic volatiles in and on the Moon within the last decade. Some of these studies have cast into question the post-Apollo view of lunar formation, the distribution and sources of volatiles in the Earth-Moon system, and the thermal and magmatic evolution of the Moon. The mineral apatite has been one of the pillars of this new field of study, and it will be the primary focus of this abstract. Although apatite has been used both to understand the abundances of volatiles in lunar systems as well as the isotopic compositions of those volatiles, the focus here will be on the abundances of F, Cl, and H2O. This work demonstrates the utility of apatite in advancing our understanding of lunar volatiles, hence apatite should be among the topics covered in the endogenous lunar volatile chapter in NVM II. Truncated ternary plot of apatite X-site occupancy (mol%) from highlands apatite and mare basalt apatite plotted on the relative volatile abundance diagram from. The solid black lines delineate fields of relative abundances of F, Cl, and H2O (on a weight basis) in the melt from which the apatite crystallized. The diagram was constructed using available apatite/melt partitioning data for fluorine, chlorine, and hydroxyl.

  9. Influence of Organic Material and Biofilms on Disinfectant Efficacy Against Listeria monocytogenes

    Directory of Open Access Journals (Sweden)

    Hilda Nyati

    2012-04-01

    Full Text Available The effects of organic material and biofilm formation on the efficacy of Suma Tab D4 chlorine tablets and Suma Bac D10 quaternary ammonium compound (QAC against Listeria monocytogenes was determined in suspension and on stainless steel and polystyrene surfaces according to standard disinfectant test methodology. Exposure to 200 and 740 mg L-1 QAC and to 150 mg L-1 active chlorine resulted in a > 5.0 log10 CFU mL-1 and > 5.0 log10 CFU/coupon reduction of six L. monocytogenes strains within one minute, in suspension tests, and on stainless steel surfaces, respectively. Additionally, there was a reduction by as much as 5 log10 CFU/coupon or 5 log10 CFU/well of reference strains EGDe and Scott A biofilms within five minutes on stainless steel and polystyrene surfaces. Organic material, added as bovine serum albumin at 0.3% (w/v completely prevented the inactivation of L. monocytogenes in 150 mg L-1 chlorine, while reductions of only 0.6 +- 0.1 log10 CFU mL-1 were recorded in the presence of UHT milk at 3% (v/v. In contrast, reductions of 5 log10 CFU mL-1 were recorded within one minute on exposure to 740 mg L-1 QAC in the presence of 0.3% (w/v bovine serum albumin and within two minutes in the presence of 20 % (v/v UHT milk. Although Suma D4 chlorine tablets and Suma Bac D10 QAC are effective listericidal agents at recommended concentrations, Suma Tab D4 chlorine efficacy against L. monocytogenes is impaired by the presence of low concentrations of organic material, while Suma Bac D10 QAC maintains its listericidal activity in high organic loads.

  10. 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...

  11. 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...

  12. Microbial community dynamics of an urban drinking water distribution system subjected to phases of chloramination and chlorination treatments.

    Science.gov (United States)

    Hwang, Chiachi; Ling, Fangqiong; Andersen, Gary L; LeChevallier, Mark W; Liu, Wen-Tso

    2012-11-01

    Water utilities in parts of the U.S. control microbial regrowth in drinking water distribution systems (DWDS) by alternating postdisinfection methods between chlorination and chloramination. To examine how this strategy influences drinking water microbial communities, an urban DWDS (population ≅ 40,000) with groundwater as the source water was studied for approximately 2 years. Water samples were collected at five locations in the network at different seasons and analyzed for their chemical and physical characteristics and for their microbial community composition and structure by examining the 16S rRNA gene via terminal restriction fragment length polymorphism and DNA pyrosequencing technology. Nonmetric multidimension scaling and canonical correspondence analysis of microbial community profiles could explain >57% of the variation. Clustering of samples based on disinfection types (free chlorine versus combined chlorine) and sampling time was observed to correlate to the shifts in microbial communities. Sampling location and water age (chlorinated water, and Methylophilaceae, Methylococcaceae, and Pseudomonadaceae were more abundant in chloraminated water. No correlation was observed with minor populations that were detected frequently (water and survived through the treatment process. Transient microbial populations including Flavobacteriaceae and Clostridiaceae were also observed. Overall, reversible shifts in microbial communities were especially pronounced with chloramination, suggesting stronger selection of microbial populations from chloramines than chlorine.

  13. 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.

  14. Two in-vivo protocols for testing virucidal efficacy of handwashing and hand disinfection.

    Science.gov (United States)

    Steinmann, J; Nehrkorn, R; Meyer, A; Becker, K

    1995-01-01

    Whole-hands and fingerpads of seven volunteers were contaminated with poliovirus type 1 Sabin strain in order to evaluate virucidal efficacy of different forms of handwashing and handrub with alcohols and alcohol-based disinfectants. In the whole-hand protocol, handwashing with unmedicated soap for 5 min and handrubbing with 80% ethanol yielded a log reduction factor (RF) of > 2, whereas the log RF by 96.8% ethanol exceeded 3.2. With the fingerpad model ethanol produced a greater log RF than iso- or n-propanol. Comparing five commercial hand disinfectants and a chlorine solution (1.0% chloramine T-solution) for handrub, Desderman and Promanum, both composed of ethanol, yielded log RFs of 2.47 and 2.26 respectively after an application time of 60 s, similar to 1.0% chloramine T-solution (log RF of 2.28). Autosept, Mucasept, and Sterillium, based on n-propanol and/or isopropanol, were found to be significantly less effective (log RFs of 1.16, 1.06 and 1.52 respectively). A comparison of a modified whole-hand and the fingerpad protocol with Promanum showed similar results with the two systems suggesting both models are suitable for testing the in-vivo efficacy of handwashing agents and hand disinfectants which are used without any water.

  15. Bromination of Marine Dissolved Organic Matter following Full Scale Electrochemical Ballast Water Disinfection.

    Science.gov (United States)

    Gonsior, Michael; Mitchelmore, Carys; Heyes, Andrew; Harir, Mourad; Richardson, Susan D; Petty, William Tyler; Wright, David A; Schmitt-Kopplin, Philippe

    2015-08-04

    An extensively diverse array of brominated disinfection byproducts (DBPs) were generated following electrochemical disinfection of natural coastal/estuarine water, which is one of the main treatment methods currently under consideration for ballast water treatment. Ultra-high-resolution mass spectrometry revealed 462 distinct brominated DBPs at a relative abundance in the mass spectra of more than 1%. A brominated DBP with a relative abundance of almost 22% was identified as 2,2,4-tribromo-5-hydroxy-4-cyclopentene-1,3-dione, which is an analogue to several previously described 2,2,4-trihalo-5-hydroxy-4-cyclopentene-1,3-diones in drinking water. Several other brominated molecular formulas matched those of other known brominated DBPs, such as dibromomethane, which could be generated by decarboxylation of dibromoacetic acid during ionization, dibromophenol, dibromopropanoic acid, dibromobutanoic acid, bromohydroxybenzoic acid, bromophenylacetic acid, bromooxopentenoic acid, and dibromopentenedioic acid. Via comparison to previously described chlorine-containing analogues, bromophenylacetic acid, dibromooxopentenoic acid, and dibromopentenedioic acid were also identified. A novel compound at a 4% relative abundance was identified as tribromoethenesulfonate. This compound has not been previously described as a DBP, and its core structure of tribromoethene has been demonstrated to show toxicological implications. Here we show that electrochemical disinfection, suggested as a candidate for successful ballast water treatment, caused considerable production of some previously characterized DBPs in addition to novel brominated DBPs, although several hundred compounds remain structurally uncharacterized. Our results clearly demonstrate that electrochemical and potentially direct chlorination of ballast water in estuarine and marine systems should be approached with caution and the concentrations, fate, and toxicity of DBP need to be further characterized.

  16. Formation and occurrence of new polar iodinated disinfection byproducts in drinking water.

    Science.gov (United States)

    Pan, Yang; Li, Wenbin; An, Hao; Cui, Hao; Wang, Ying

    2016-02-01

    During drinking water disinfection, iodinated disinfection byproducts (I-DBPs) can be generated through reactions between iodide, disinfectants, and natural organic matter. Drinking water I-DBPs have been increasingly attracting attention as emerging organic pollutants as a result of their significantly higher toxicity and growth inhibition than their chloro- and bromo-analogues. In this study, by adopting ultra performance liquid chromatography/electrospray ionization-triple quadrupole mass spectrometry precursor ion scan, multiple reaction monitoring, and product ion scan analyses, 11 new polar I-DBPs with confirmed structures and eight new polar I-DBPs with proposed structures were detected in simulated drinking water samples. Chloramination of simulated raw waters containing natural organic matter with higher aromaticity produced higher levels of new phenolic I-DBPs. Formation of new polar I-DBPs and total organic iodine (TOI) was most favored in chloramination, followed by chlorine dioxide treatment, and relatively minor in chlorination. Lower pH in chloramination substantially enhanced the formation of new polar I-DBPs and TOI. NH2Cl and dissolved organic nitrogen could be important nitrogen sources and precursors for formation of the two new nitrogenous phenolic I-DBPs. Notably, in tap water samples collected from nine major cities located in the Yangtze River Delta region of China, seven of the 11 new polar I-DBPs with confirmed structures were detected at levels from 0.11 to 28 ng/L, and the two new nitrogenous phenolic I-DBPs were ubiquitous with concentrations from 0.12 to 24 ng/L, likely due to the relatively high dissolved organic nitrogen levels in regional source waters. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. 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.

  18. 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

  19. Susceptibility of chemostat-grown Yersinia enterocolitica and Klebsiella pneumoniae to chlorine dioxide.

    Science.gov (United States)

    Harakeh, M S; Berg, J D; Hoff, J C; Matin, A

    1985-01-01

    The resistance of bacteria to antimicrobial agents could be influenced by growth environment. The susceptibility of two enteric bacteria, Yersinia enterocolitica and Klebsiella pneumoniae, to chlorine dioxide was investigated. These organisms were grown in a defined medium in a chemostat and the influence of growth rate, temperature, and cell density on the susceptibility was studied. All inactivation experiments were conducted with a dose of 0.25 mg of chlorine<