Effect Of Free Chlorine Research Articles

Realism-based assessment of the efficacy of potassium peroxymonosulphate on Stenotrophomonas maltophilia biofilm control

The potential of pentapotassium bis(peroxymonosulphate) bis(sulphate) (OXONE) to control biofilms in drinking water distribution systems (DWDS) was evaluated and compared to chlorine disinfection. Mature biofilms of drinking water (DW)-isolated Stenotrophomonas maltophilia were formed using a simulated DWDS with a rotating cylinder reactor (RCR). After 30 min of exposure, OXONE at 10 × minimum bactericidal concentration (MBC) caused a significant 4 log reduction of biofilm culturability in comparison to the unexposed biofilms and a decrease in the number of non-damaged cells below the detection limit (4.8 log cells/cm2). The effects of free chlorine were restricted to approximately 1 log reduction in both biofilm culturability and non-damaged cells. OXONE in synthetic tap water (STW) at 25 ºC was more stable over 40 days than free chlorine in the same conditions. OXONE solution exhibited a disinfectant decrease of about 10% of the initial concentration during the first 9 days, and after this time the values remained stable. Whereas possible reaction of chlorine with inorganic and organic substances in STW contributed to free chlorine depletion of approximately 48% of the initial concentration. Electron paramagnetic resonance (EPR) spectroscopy studies confirmed the presence of singlet oxygen and other free radicals during S. maltophilia disinfection with OXONE. Overall, OXONE constitutes a relevant alternative to conventional DW disinfection for effective biofilm control in DWDS.

Insight into the formation of polyhalogenated carbazoles during seawater chlorination

Although polyhalogenated carbazoles (PHCZs) have been widely detected in the marine environment, their origin is far from clear. In this study, the formation of PHCZs in the chlorination of seawater containing carbazole and its derivatives was investigated. A total of 14 PHCZs including six commonly found and eight unknown congeners were identified in the chlorination of seawater with carbazole. In addition, this study for the first time demonstrated the production of common PHCZs from the chlorination of seawater with 3-methyl carbazole and 3-formyl carbazole, especially 1,8-dibromo-3,6-dichlorocarbazole from 3-methyl carbazole. The formation of PHCZs in the reaction resulted from the halogenation of carbazole by reactive chlorine species (RCS) and mainly reactive bromine species (RBS), forming from the oxidation of bromide by RCS. Results also indicated that the reaction followed a successive halogenation pattern. A higher content of free chlorine and bromide facilitated the generation of RBS, while a higher concentration of DOC exhibited an inhibitory effect. The effects of free chlorine, bromide, DOC, and temperature on the formation of PHCZs were congener-specific. Given the widespread use of chlorination in seawater disinfection, seawater chlorination might be a potential source of PHCZs in the marine environment.

Inactivation of Ascaris eggs in water using sequential solar driven photo-Fenton and free chlorine

Sequential helminth egg inactivation using a solar driven advanced oxidation process (AOP) followed by chlorine was achieved. The photo-assisted Fenton process was tested alone under different H(2)O(2) and/or Fe(II) concentrations to assess its ability to inactivate Ascaris suum eggs. The effect of free chlorine alone was also tested. The lowest egg inactivation results were found using Fe(II) or H(2)O(2) separately (5 and 140 mmol L(-1), respectively) in dark conditions, which showed about 28% inactivation of helminth eggs. By combining Fe(II) and H(2)O(2) at the same concentrations described earlier, 55% of helminth egg inactivation was achieved. By increasing the reagent's concentration two-fold, 83% egg inactivation was achieved after 120 min of reaction time. Process efficiency was enhanced by solar excitation. Using solar disinfection only, the A. suum eggs inactivation reached was the lowest observed (58% egg inactivation after 120 min (120 kJ L(-1))), compared with tests using the photo-Fenton process. The use of the photo-Fenton reaction enhanced the process up to over 99% of egg inactivation after 120 kJ L(-1) when the highest Fe(II) and H(2)O(2) concentration was tested. Practically no effect on the helminth eggs was observed with free chlorine alone after 550 mg min L(-1) was used. Egg inactivation in the range of 25-30% was obtained for sequential processes (AOP then chlorine) using about 150 mg min L(-1).

Impact of Chlorine Disinfectants on Dissolution of the Lead Corrosion Product PbO2

Plattnerite (β-PbO(2)) is a corrosion product that develops on lead pipes that have been in contact with free chlorine present as a residual disinfectant. The reductive dissolution of PbO(2) can cause elevated lead concentrations in tap water when the residual disinfectant is switched from free chlorine to monochloramine. The objectives of this study were to quantify plattnerite dissolution rates in the presence of chlorine disinfectants, gain insights into dissolution mechanisms, and measure plattnerite's equilibrium solubility in the presence of free chlorine. The effects of free chlorine and monochloramine on the dissolution rates of plattnerite were quantified in completely mixed continuous-flow reactors at relevant pH and dissolved inorganic carbon conditions. Plattnerite dissolution rates decreased in the following order: no disinfectant > monochloramine > chlorine, which was consistent with the trend in the redox potential. Compared with experiments without disinfectant, monochloramine inhibited plattnerite dissolution in continuous-flow experiments. Although free chlorine maintained steady-state lead concentrations below the action level of 15 μg/L in flow-through experiments, in batch experiments lead concentrations exceeded the action level for longer residence times and approached an equilibrium value that was several orders of magnitude higher than that predicted from available thermodynamic data.

Effects of free chlorine on the respiration of seaweeds

Effects of free chlorine on the respiration of seaweeds

Effect of free chlorine and chloramines on lead release in a distribution system

Total lead release in the presence of free chlorine and chloramine residuals was investigated in drinking waters produced from ground, surface, desalinated, and blended water sources. For desalinated and blended finished waters, more total lead was released in the presence of chloramine than in the presence of free chlorine; for finished groundwater and surface water, however, no statistical differences in total lead release were found. Finished water oxidation‐reduction potential (ORP) differed by residual type but was equivalent by source and not affected by the addition of 100 mg/L of sulfates or chlorides. ORP measurement and development of Pourbaix diagrams showed that lead dioxide was the controlling solid phase in the presence of chlorine, and hydrocerussite was the controlling solid phase in the presence of chloramine. Lead dioxide is less soluble than hydrocerussite, which mechanistically accounted for the lower lead release in the presence of free chlorine.

The effect of free chlorine on Burkholderia pseudomallei in potable water

Chlorine is widely used in public water supplies to provide a disinfection barrier. The effect of chlorine disinfection on the water-borne pathogen Burkholderia pseudomallei was assessed using multiple techniques. After exposure to chlorine viable bacteria were undetectable by conventional plate count techniques; however, persistence of B. pseudomallei was verified by flow cytometry and bacteria were recoverable following a simple one-step broth procedure. The minimum residual chlorine concentration and contact time as prescribed by potable water providers in Australia was insufficient to reduce a B. pseudomallei population by more than 2 log 10. Chlorine had a bacteriostatic effect only on B. pseudomallei; viable bacteria were recovered from water containing up to 1000 ppm free chlorine. This finding has practical implications for water treatment in regions where B. pseudomallei is endemic. Future work to assess the effect of alternative water disinfection processes either singly or in sequence is necessary.

Long term durability of crosslinked polyethylene tubing used in chlorinated hot water systems

The objectives of the present research are to understand better the degradation of crosslinked polyethylene tubing subjected to pressurised, hot chlorinated water in flow through systems (e.g. home plumbing) and to estimate its service lifetime. Crosslinked polyethylene tubing was subjected to pressure testing with flowing hot, chlorinated water at elevated temperatures from 90 to 120°C, with chlorine levels between 0 and 5 ppm. The combined effects of free chlorine, pH, and metal ion content on the time to failure were found to correlate better with the oxidation–reduction potential than with the free chlorine content directly. Consumption of the antioxidant was analysed using the oxidation induction time as a function of fraction of the time to failure in the tests, with the antioxidant being found to be completely consumed in less than half the time to failure at 115°C. Fractographic observations made using a scanning electron microscope indicated no degradation until the antioxidant was completely consumed. The nature of the damage at failure was investigated using highly polished cross-sections of pipe, which failed by a pinhole leak.

The effect of free chlorine onEscherichia coli populations

The effect of free chlorine onEscherichia coli populations was studied by chlorination of a population of 105 cells/ml. This cell density was low enough for the free-to-combined chlorine ratio to be 6.0∶1 or greater. The predominance of free chlorine resulted in rapid and complete population death.

Chlorinated cooling waters in the marine environment: Development of effluent guidelines

The effects of free chlorine and chloramine on stage I lobster larvae and juvenile killifish were investigated in continuous flow bioassay units. In comparing mortality and changes in standard respiration rates during and after exposure to either chlorine form, significant respiratory stress was observed with exposure to sublethal levels. Sublethal responses to free and combined chlorine should be considered when establishing regulations for chlorine residuals in cooling waters.

The effects of free chlorine and chloramine on growth and respiration rates of larval lobsters ( Homarus Americanus)

The length, dry weight and standard respiration rate of larval lobsters ( Homarus americanus) were monitored for 19 days following a 60 min exposure at 25°C to 1.0 mg I −1 applied free chlorine and 1.0 mg I −1 applied chloramine. Compared to control organisms, significantly lower increases in dry weight ( P < 0.05) and significant reductions in standard respiration rates ( P < 0.01) were measured among exposed organisms; greater differences were detected among chloramine exposed organisms. From these results it can be concluded that acute exposure to either free chlorine or chloramine results in subsequent reductions in growth and metabolic activity of larval lobsters.

海水冷却チューブの孔食に及ぼす遊離塩素の影響

海水冷却チューブの孔食に及ぼす遊離塩素の影響

Effectiveness of Halogens or Halogen Compounds in DetoxifyingClostridium botulinumToxins

Journal AWWAVolume 51, Issue 7 p. 902-912 Article Effectiveness of Halogens or Halogen Compounds in Detoxifying Clostridium botulinum Toxins A. Richard Brazis, A. Richard BrazisSearch for more papers by this authorAlton R. Bryant, Alton R. BryantSearch for more papers by this authorJames E. Leslie, James E. LeslieSearch for more papers by this authorRichard L. Woodward, Richard L. WoodwardSearch for more papers by this authorPaul W. Kabler, Paul W. KablerSearch for more papers by this author A. Richard Brazis, A. Richard BrazisSearch for more papers by this authorAlton R. Bryant, Alton R. BryantSearch for more papers by this authorJames E. Leslie, James E. LeslieSearch for more papers by this authorRichard L. Woodward, Richard L. WoodwardSearch for more papers by this authorPaul W. Kabler, Paul W. KablerSearch for more papers by this author First published: 01 July 1959 https://doi.org/10.1002/j.1551-8833.1959.tb21177.xCitations: 5AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Citing Literature Volume51, Issue7July 1959Pages 902-912 RelatedInformation

Chlorine in Distilled Water as a Source of Laboratory Error

Abstract Some distillation processes may result in the inadvertent contamination of distilled water with free chlorine. One part per million of free chlorine in distilled water has been shown to inhibit markedly the color development in the usual determinations of uric acid and bilirubin. The effect of free chlorine on other clinical chemistry determinations is discussed and simple tests for the detection of free chlorine in water are reviewed.