free chlorine level Articles

  • 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. ...

  • 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

  • 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 ...

  • 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 ...

  • 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 ...


    By ClearWater Tech LLC

  • Pilot-scale electrochemical disinfection of surface water: assessing disinfection by-product and free chlorine formation

    Electrochemical disinfection of surface water using mixed metal oxide anodes was evaluated in a pilot-scale demonstration. Disinfection rates, chlorine generation, energy demand, and generation of disinfection by-products were monitored over the 190-day study. Particular attention was given to the generation of trihalomethanes (THMs) and haloacetic acids (HAAs) during the electrochemical ...


    By IWA Publishing

  • 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 ...

  • 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 ...


    By GEO Inc

  • 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 ...

  • 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 ...

  • Chlorine requirement for biologically stable drinking water after nanofiltration

    There is considerable interest in minimizing the chlorine residual in Japan's tap water because of increasing consumer complaints about the chlorinous odor of drinking water. However, minimization of the chlorine residual requires stricter control of biodegradable organics in finished water to ensure biological stability during water distribution. In this context, we investigated the ...


    By IWA Publishing

  • Factors Affecting Cyanide Generation in Chlorinated Wastewater Effluent Matrix

    ABSTRACTFalse positives for cyanide analysis in wastewaters have been reported. We examined the effects of storage time at high pH and of pH adjustments on the cyanide levels. Cyanide levels changed within the holding time allowed by Standard Methods. We also studied the difference in cyanide levels using two disinfection conditions -- breakpoint chlorination and chloramination. Glycine was used ...

  • Chlorine inactivation of hepatitis E virus and human adenovirus 2 in water

    Hepatitis E virus (HEV) is transmitted via the fecal–oral route and has been recognized as a common source of large waterborne outbreaks involving contaminated water in developing countries. Thus, there is the need to produce experimental data on the disinfection kinetics of HEV by chlorine in water samples with diverse levels of fecal contamination. Here, the inactivation of HEV and ...


    By IWA Publishing

  • Point-of-use chlorination of turbid water: results from a field study in Tanzania

    Household-based chlorine disinfection is widely effective against waterborne bacteria and viruses, and may be among the most inexpensive and accessible options for household water treatment. The microbiological effectiveness of chlorine is limited, however, by turbidity. In Tanzania, there are no guidelines on water chlorination at household level, and limited data on whether dosing guidelines ...


    By IWA Publishing

  • Bacteria-free water - without the use of toxic chemicals - Case Study

    Aarhus University Hospital fought against Legionella bacteria – and won Legionella bacteria thrives in all hot-water supplies and Aarhus University Hospital, Risskov felt the problem firsthand. With the ECA generator from Danish Clean Water A/S they managed to significantly reduce the bacteria and thereby minimizing risks concerning Legionella. Virtually all hospitals, ...


    By Danish Clean Water A/S

  • Chemical-Free Treatment of Recirculating Water Using Pulsed-Power

    Untitled Document Regulatory pressures and economic considerations require industry to become cleaner, more efficient, and more environmentally benign. Such operating principles advance not only ...


    By Dolphin WaterCare

  • On the usage of artificial neural networks in chlorine control applications for water distribution networks with high quality water

    Artificial neural network (ANN) methodology has found some recent applications as efficient control tools for satisfying free residual chlorine (FRC) levels at critical locations of water distribution systems. This particular research was started to critically investigate the potential and applicability of the ANN approach as a tool for controlling FRC levels for complex water distribution ...


    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

  • Evaluation of Ecological Risks Associated with the use of Chlorine Dioxide for the Bleaching of Pulp: Scientific Progress Since 1993

    1.1 Scope and Objectives A small number of viable options are presently available for the bleaching of wood pulp (delignification and brightening) during the manufacture of pulp and paper. The use of chlorine dioxide (ClO2) in the bleaching process has largely superceded the earlier use of Cl2, or elemental chlorine, in the majority of North American pulp mills: It was discovered over a decade ...

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