free chlorine comparator Articles

  • Accuracy, precision, usability, and cost of free chlorine residual testing methods

    Chlorine is the most widely used disinfectant worldwide, partially because residual protection is maintained after treatment. This residual is measured using colorimetric test kits varying in accuracy, precision, training required, and cost. Seven commercially available colorimeters, color wheel and test tube comparator kits, pool test kits, and test strips were evaluated for use in low-resource ...


    By IWA Publishing

  • The synergistic effect of Escherichia coli inactivation by sequential disinfection with low level chlorine dioxide followed by free chlorine

    To the best of our knowledge, there was little information available on pathogen removal using low level disinfectant followed by free chlorine in sequential disinfection (SD). This study investigated Escherichia coli inactivation by four types of disinfection: single step disinfection (SSD), SD, traditional sequential disinfection (TSD) and mixed disinfectant disinfection (MDD). Results ...


    By IWA Publishing

  • Chlorine mystery solved

    Following the installation of in-pipe drinking water quality monitoring sondes, distribution engineers discovered an occasional significant disparity between the Intellisondes’ data and results from grab samples tested by a photometer tablet (DPD) method. For most of the time, there was close agreement between the two methods, but periodically, the photometer results varied wildly, whilst ...


    By Intellitect Water Ltd

  • Sanitation Using Ozone & Chlorine

    For nearly 100 years, ozone has been used all over the world for water sanitation. It is nature’s strongest oxidizer and has a byproduct of pure oxygen. Chlorine, on the other hand, is a very effective, time-proven chemical, but is ineffective against hard-to-kill microorganisms such as cryptosporidium. It also has some unpleasant byproducts. Together, however, these two substances can ...

  • Inactivation of Cryptosporidium Parvum oocysts and Clostridium Perfringens spores by a mixed-oxidant disinfectant and by free Chlorine

    Cryptosporidium parvum oocysts and Clostridium perfringens spores are very resistant to chlorine and other drinking-water disinfectants. Clostridium perfringens spores have been suggested as a surrogate indicator of disinfectant activity against Cryptosporidium parvum and other hardy pathogens in water. In this study, an alternative disinfection system consisting of an electrochemically produced ...


    By MIOX Corporation

  • Performance of chlorination process during nanofiltration of sulfonamide antibiotic

    The effectiveness of combined nanofiltration and disinfection processes was studied by comparing the pre-disinfection and post-disinfection when in combination with nanofiltration. Four types of sulfonamide (sulfanilamide, sulfadiazine, sulfamethoxazole, and sulfadimethoxine) were chosen as substrates, with sodium hypochlorite as a disinfectant. A laboratory-scale nanofiltration system was ...


    By IWA Publishing

  • Chlorine Dioxide gas detection: A comprehensive guide

    Introduction Some years agoago, the bleaching process in the paper industry was changed from using Chlorine (Cl2) as bleaching agent to Chlorine dioxide (ClO2). This was a challenge forThis posed a major challenge to industrial hygienists, as there were no sensors or detectors available that were specific to Chlorine dioxide: There was no sensor technology for gas detectors available that ...

  • Effect of water hardness and pipe material on enhanced disinfection with UV light and chlorine

    Limited studies have been conducted to evaluate synergistic benefits between disinfectants, although promise has been shown between ultraviolet (UV) light and chlorine-based disinfectants. This research aimed to determine drinking water quality factors that affect potential for enhanced removal of heterotrophic bacteria due to synergy between UV light and free chlorine. An additional goal was to ...


    By IWA Publishing

  • Field trial of an automated batch chlorinator system at shared water points in an urban community of Dhaka, Bangladesh

    Point-of-use water treatment with chlorine is underutilized in low-income households. The Zimba, an automated batch chlorinator, requires no electricity or moving parts, and can be installed at shared water points with intermittent flow. We conducted a small-scale trial to assess the acceptability and quality of Zimba-treated municipal water. Fieldworkers collected stored drinking water over a ...


    By IWA Publishing

  • Association Between Swimming Pool Operator Certification and Reduced Pool Chemistry Violations—Nebraska, 2005–2006

    Previous studies have recommended mandatory education for all public pool operators, but substantiating data are limited. This study evaluates associations between pool operator certification and chemistry violations by using 2005–2006 Nebraska routine pool inspection reports. Training and certification for nonmunicipal pool operators are only required in two Nebraska counties. Free chlorine ...

  • Oxidized fulvic acid adsorption on activated carbon

    This study evaluates and compares the parameters of equilibrium adsorption from aqueous solutions of river fulvic acids (FA) and peat fulvic acids. Compared to peat FA, the river FA had lower biodegradable dissolved organic carbon (BDOC). We observed a tendency for correlation between change of Gibbs free energy of adsorption and BDOC value. A chlorination dose of 1.4 mg L−1 did not ...


    By IWA Publishing

  • Mixed Oxidants show disinfection benefits for municipalities

    “The most significant advantage over gas chlorination or hypochlorination is an ability to maintain chlorine residuals further along the water distribution system, due to better biofilm removal. Other noted advantages of mixed oxidants are ease of operation with self-cleaning electrolytic cell on-site generators, fewer safety issues in comparison to gas chlorination, and lower costs ...


    By MIOX Corporation

  • Autocalibration of dynamic bacterial growth model for water distribution system using GA

    The presence of residual chlorine and organic matter govern the bacterial regrowth within a water distribution system. The bacterial growth model is essential to predict the spatial and temporal variation of all these substances throughout the system. The parameters governing the bacterial growth and biodegradable dissolved organic carbon (BDOC) utilization are difficult to determine by ...


    By IWA Publishing

  • Comparison of dechlorination rates and water quality impacts for sodium bisulfite, sodium thiosulfate and ascorbic acid

    The impact of water quality parameters such as organic and inorganic matter as well as chlorine species (free chlorine and monochloramine) on the rate of dechlorination by sodium bisulfite (SBS), sodium thiosulfate (STS) and ascorbic acid (AA) were studied. Reaction rate constants determined for the various dechlorination reactions showed that SBS and AA achieved dechlorination at a faster rate ...


    By IWA Publishing

  • Chlorites Control in European Drinking Water Treatment Plants

    ABSTRACT The paper reports initial results for experiments carried out at Fortore drinking water treatment plant aimed at controlling chlorites. Research was performed in parallel with a full-scale drinking water plant (Fortore, Italy) and a pilot plant at Mosina water treatment plant which supplies potable water to the city of Poznań (Poland). Both plants operated with pre-disinfection ...

  • Performic acid for advanced wastewater disinfection

    The disinfection efficiency of performic acid (PFA) against various microbial contaminants has been studied in municipal secondary effluent. The study demonstrated that PFA provides rapid, efficient and safe disinfection, degrading both bacteria and viruses even at low doses. The resistance order starting from the most resistant microorganism is as follows: MS2-coliphages > DNA-coliphages ...


    By IWA Publishing

  • Occurrence of Aeromonas spp. in a random sample of drinking water distribution systems in the USA

    Aeromonads are aquatic bacteria found in drinking water supplies worldwide. Some species, such as Aeromonas hydrophila, can cause disease in humans. For this survey, 293 United States public water systems were selected using random sampling, stratified by water source and system type. Water samples were collected during one year from three sites (six samples per site) in each system. Temperature, ...


    By IWA Publishing

  • Effects of mixing on chloramination process

    According to a recent study more than 90 percent of water treatment plants utilizing chloramination for distribution system residuals indicate a certain level of dissatisfaction toward the process performance. One factor that may lead to such dissatisfaction is the inadequacy of mixing when ammonia is added to chlorinated water. If mixing is not instantaneous and uniform, the actual chlorine to ...


    By IWA Publishing

  • Variation of algal viability during electrochemical disinfection using Ti/RuO2 electrodes

    This paper studied the influence of the operating conditions, e.g. current density, electrolyte and exposure time, on the variation of the algal viability during electrochemical disinfection processes. An electrochemical tube employing Ti/RuO2 as anodes was constructed for inactivation of cyanobacteria (often called blue-green algae) Microcystis aeruginosa. Viability of algal cells was determined ...


    By IWA Publishing

  • Chloramines

    OVERVIEW When chlorine is added to a water supply containing certain organics, the formation of halogenated organics occurs. Called 'trihalogenated methanes' (THM's) these reaction products are suspected carcinogens and maximum allowable limits in municipal supplies are imposed by the U.S. Environmental Protection Agency (EPA). To reduce the potential for the formation of THM's, many U.S. ...

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