free chlorine Articles

  • What’s the difference between free and total chlorine?

    The element Chlorine exists as a gas Cl2, when this is mixed with water it forms hypochlorous acid (HOCl) which is the disinfecting agent; Cl2 + H2O HCl + HOCl This HOCl can partly disassociate to form the hypochlorite ion ...


    By Camlab Limited

  • Amperometric Free Chlorine Measurement without pH Compensation

    Accurate measurement and control of free chlorine in water is critical in many applications. Amperometric sensors are a popular alternative to colorimetric analyzers since the measurement is continuous and no reagents are required, however most sensors are extremely sensitive to pH fluctuations and have a limited pH range where they will function. Expensive pH measurement and control is one ...


    By Walchem, Iwaki America Inc.

  • Ultraviolet Light Oxidation of Free-Chlorine in Water

    Chlorine is the most frequently used chemical for water disinfection. Many industrial and commercial manufacturing facilities cannot tolerate the introduction of chlorine into the process because of contamination and unwanted chemical reactions. Chlorine affects the flavour and odour of drinks and fluids, accelerates corrosion on process vessels and piping, and can also damage delicate process ...

  • Elemental Chlorine-Free (ECF): Pollution Prevention for the Pulp and Paper Industry

    Imagine being in charge of a chemical company. One day a fire breaks out, and an employee, designated as a first responder, is killed fighting the blaze. Then OSHA investigators discover that the man died primarily because both his training and his equipment were inadequate. This scenario is why CPL 2-2.59A should put anyone who runs a HAZMAT facility into a state of introspection. These ...

  • 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

  • Inactivation of human adenovirus by sequential disinfection with an alternative UV technology and free chlorine

    There has been growing concern over human exposure to adenoviruses through drinking water due to the extreme resistance of human adenoviruses to the traditional UV technology (low-pressure (LP) UV). As an effort to develop an effective treatment strategy against human adenoviruses in drinking water, we determined the effectiveness of sequential disinfection with an alternative UV technology ...


    By IWA Publishing

  • Security Aspects of the Free Chlorine Vs Monochloramine Debate for Disinfection by Product Control

     Introduction: In recent years, there has been a move away from the utilization of free chlorine to maintain a residual level of disinfectant in the distribution system towards the use of monochloramine. The reason behind this change is to decrease the formation of disinfection byproducts (DBPs), which are created when the free chlorine reacts with organic material in the water. The use ...

  • Case study - Elemental chlorine free kraft pulp bleaching and chlorine dioxide scrubbing

    Chlorine Dioxide - CIO2 Scrubber Packing at Kraft Pulp Mills Elemental Chlorine Free - ECF - bleaching of wood pulp using Chlorine Dioxide, CIO2, as the primary bleaching agent eliminates dioxin emissions. This is a reflection of the fact that as a bleaching agent CIO2 is 10 times more reactive than elemental Chlorine, Ck. As a powerful oxidizing agent CIO2 must be generated on site - ...


    By Raschig USA Inc.

  • 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 levels in pools

    In response to a SportExcel CPD seminar in April 2004 on pool water disinfection ISRM is reissuing this updated guidance. Also, recent press reports have highlighted the theoretical risks of high chlorine levels in swimming pools in relation to both pregnant women and levels of childhood asthma. This further reinforces the need for operators to provide the highest pool water standards possible. ...

  • 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

  • Chlorine Theory & Measurement

    Chlorine, dissolved in liquid is one of the most effective and economical semi-killers for the treatment of water to make it potable or safe to drink. Chlorine's powerful disinfectant qualities come from its ability to bond with and destroy the outer surfaces of bacteria and viruses. Drinking water chlorination is one of the most widely used methods to safeguard chinking water supplies. In ...


    By IC Controls 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

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

    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, ...


    By IWA Publishing

  • Drinking water: the problem of chlorinous odours

    Chlorinous off-flavours in drinking water are a leading cause of complaints to Australian water utilities and other utilities worldwide. The occurrence and causes of chlorinous odours in drinking water were investigated with the use of an odour panel, trained using a modified flavour profile analysis technique. A new system for classifying water types according to the causes of chlorinous odours ...


    By IWA Publishing

  • Chlorinated solvents: methylene chloride and TCE

    Introduction This paper presents the results of a scaled and phased approach to source remediation of high concentrations of recalcitrant chlorinated solvent compounds via soil vapor extraction (SVE) and vapor treatment at a Site in Southern California. Phase I began with refrigerated condensation (C3) in order to achieve high mass removal rates to reduce lifecycle costs and time ...

  • Sequential chlorination for reclaimed water disinfection

    ABSTRACT The Sanitation Districts of Los Angeles County (Districts) operate seven tertiary water reclamation plants (WRPs) with a combined treatment capacity of approximately 200 million gallons per day (MGD). Chloramination is used at these WRPs for effluent disinfection. It was recently discovered that chloramination results in formation of N-nitrosodimethylamine (NDMA), a compound with ...

  • Investigating the performance of a UV/H2O2 integrated flow-through system followed by free chlorine

    Ultraviolet (UV) irradiation is an emerging technique for drinking water disinfection due to effective removal of enteric pathogens without generation of disinfection by-products (DBPs). In order to overcome the drawback of UV irradiation the integration of UV disinfection with sequential disinfectant was proposed. Among all the possible combinations and sequences, a ...


    By IWA Publishing

  • Chlorination Disinfection Requirements for Membrane Bioreactor Permeate

     ABSTRACT The membrane bioreactor (MBR) process is typically designed and operated to produce a fully nitrified, high quality effluent (permeate) that makes it possible to use free chlorine for disinfection. In California, regulations (Title 22) require a minimum CT value of 450 mg-min/L or 5-log virus inactivation when chlorine is used to produce “disinfected tertiary effluent.” In ...

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