An evaluation of the methods for determining residual chlorine in water. Part I. Free chlorine

The Analyst ◽  
1965 ◽  
Vol 90 (1069) ◽  
pp. 187 ◽  
Author(s):  
N. J. Nicolson
Keyword(s):  
Free Chlorine ◽  
Residual Chlorine

scholarly journals First Derivative UV Spectra of Surface Water as a Monitor of Chlorination in Drinking Water Treatment

2001 ◽  
Vol 1 ◽  
pp. 39-43 ◽  
Author(s):  
V. Zitko
Keyword(s):  
Drinking Water ◽  
Water Treatment ◽  
Surface Water ◽  
Distribution System ◽  
Drinking Water Treatment ◽  
Uv Spectra ◽  
Free Chlorine ◽  
Residual Chlorine ◽  
First Derivative ◽  
Derivative Spectra

Many countries require the presence of free chlorine at about 0.1 mg/l in their drinking water supplies. For various reasons, such as cast-iron pipes or long residence times in the distribution system, free chlorine may decrease below detection limits. In such cases it is important to know whether or not the water was chlorinated or if nonchlorinated water entered the system by accident. Changes in UV spectra of natural organic matter in lakewater were used to assess qualitatively the degree of chlorination in the treatment to produce drinking water. The changes were more obvious in the first derivative spectra. In lakewater, the derivative spectra have a maximum at about 280 nm. This maximum shifts to longer wavelengths by up to 10 nm, decreases, and eventually disappears with an increasing dose of chlorine. The water treatment system was monitored by this technique for over 1 year and changes in the UV spectra of water samples were compared with experimental samples treated with known amounts of chlorine. The changes of the UV spectra with the concentration of added chlorine are presented. On several occasions, water, which received very little or no chlorination, may have entered the drinking water system. The results show that first derivative spectra are potentially a tool to determine, in the absence of residual chlorine, whether or not surface water was chlorinated during the treatment to produce potable water.

scholarly journals Electrochemical Detection of Free-Chlorine in Water Samples Facilitated by In-Situ pH Control Using Interdigitated Microelectrodes

2020 ◽  
Author(s):  
Alan O'Riordan ◽  
Benjamin O'sullivan ◽  
Pierre Lovera ◽  
Ian Seymour ◽  
James Rohan
Keyword(s):  
Water Samples ◽  
Hypochlorous Acid ◽  
Control Method ◽  
Tap Water ◽  
Distribution Networks ◽  
Ph Control ◽  
Free Chlorine ◽  
Residual Chlorine ◽  
Solution Ph

Residual free-chlorine concentration in water supplies is a key metric studied to ensure disinfection. High residual chlorine concentrations lead to unpleasant odours and tastes, while low concentrations may lead to inadequate disinfection. The concentration is most commonly monitored using colorimetric techniques which require additional reagents. Electrochemical analysis offers the possibility for in-line analysis without the need for additional reagents. Electrochemical-based detection of chlorine is influenced by the solution pH, which defines the particular chlorine ionic species present in solution. As such, controlling the pH is essential to enable electrochemical based detection of residual chlorine in water. To this end, we explore the application of solid state interdigitated electrodes to tailor the in-situ pH of a solution while simultaneously detecting free-chlorine. Finite element simulations and subsequent electrochemical characterization, using gold interdigitated microelectrode arrays, were employed to explore the feasibility of an in-situ pH control approach. In practice, the approach converted residual chlorine from an initial mixture of two species (hypochlorous acid and hypochlorite ion), to one species (hypochlorous acid). Chlorine detection was shown in water samples using this exploratory method, resulting in a two-fold increase in signal response, compared to measurements without pH control. Finally, tap water samples were measured using the in-situ pH control method and the results showed excellent correlation (within experimental error) with a commercial instrument, demonstrating the efficacy of the developed technique. This work establishes the possibility of deploying an electrochemical based reagent-free, in-line chlorine sensor required for water distribution networks.

Electrochemical Detection of Free-Chlorine in Water Samples Facilitated by In-Situ pH Control Using Interdigitated Microelectrodes

2020 ◽  
Author(s):  
Alan O'Riordan ◽  
Benjamin O'sullivan ◽  
Pierre Lovera ◽  
Ian Seymour ◽  
James Rohan
Keyword(s):  
Water Samples ◽  
Hypochlorous Acid ◽  
Control Method ◽  
Tap Water ◽  
Distribution Networks ◽  
Ph Control ◽  
Free Chlorine ◽  
Residual Chlorine ◽  
Solution Ph

Residual free-chlorine concentration in water supplies is a key metric studied to ensure disinfection. High residual chlorine concentrations lead to unpleasant odours and tastes, while low concentrations may lead to inadequate disinfection. The concentration is most commonly monitored using colorimetric techniques which require additional reagents. Electrochemical analysis offers the possibility for in-line analysis without the need for additional reagents. Electrochemical-based detection of chlorine is influenced by the solution pH, which defines the particular chlorine ionic species present in solution. As such, controlling the pH is essential to enable electrochemical based detection of residual chlorine in water. To this end, we explore the application of solid state interdigitated electrodes to tailor the in-situ pH of a solution while simultaneously detecting free-chlorine. Finite element simulations and subsequent electrochemical characterization, using gold interdigitated microelectrode arrays, were employed to explore the feasibility of an in-situ pH control approach. In practice, the approach converted residual chlorine from an initial mixture of two species (hypochlorous acid and hypochlorite ion), to one species (hypochlorous acid). Chlorine detection was shown in water samples using this exploratory method, resulting in a two-fold increase in signal response, compared to measurements without pH control. Finally, tap water samples were measured using the in-situ pH control method and the results showed excellent correlation (within experimental error) with a commercial instrument, demonstrating the efficacy of the developed technique. This work establishes the possibility of deploying an electrochemical based reagent-free, in-line chlorine sensor required for water distribution networks.

1,3,5-Trimethoxybenzene (TMB) as a new quencher for preserving redox-labile disinfection byproducts and for quantifying free chlorine and free bromine

2018 ◽  
Vol 4 (7) ◽  
pp. 926-941 ◽  
Author(s):  
Stephanie S. Lau ◽  
Ryan P. Dias ◽  
Kayla R. Martin-Culet ◽  
Nicholas A. Race ◽  
Marella H. Schammel ◽  
...  
Keyword(s):  
Disinfection Byproducts ◽  
Free Chlorine ◽  
Residual Chlorine ◽  
Free Bromine

1,3,5-Trimethoxybenzene can be used to quench residual chlorine and bromine without altering disinfection byproducts that are reactive toward traditional quenchers.

scholarly journals Drinking Water Treatment at Home: a Trial in Dhaka, Bangladesh

1970 ◽  
Vol 44 (2) ◽  
pp. 233-240
Author(s):  
NA Molla ◽  
KA Mollah ◽  
A Hossain ◽  
O Shipin ◽  
HP Nur ◽  
...  
Keyword(s):  
Drinking Water ◽  
Low Income ◽  
Strong Association ◽  
Pilot Trial ◽  
Drinking Water Treatment ◽  
Free Chlorine ◽  
Faecal Coliform ◽  
Residual Chlorine ◽  
Trial Period ◽  
Survey Analysis

The pilot trial on AquatabsTM disinfectant tablets was undertaken over a period of one month (three 10-day period excluding the pre- and post-trial activities) during October-December 2004 in an area of low-income urban communities suffering from a lack of basic health services including a lack of adequate and safe water and sanitation facilities (Lalbagh) as well as adjacent areas of old Dhaka. Drinking water consumed by 347 persons was treated in 50 households comprising 70 children under 5 years old. A pre-trial survey and testing of the water supplies demonstrated that the mean faecal coliform count was > 103 MPN/100mL and that all children (100%) belonged to a "Severe Diarrhoea Group" (> 3 incidences of light diarrhoea or any serious diarrhoeal condition). One effervescent AquatabsTM (67mg sodium dichloroisocyanurate) was added by the mother to the local container (filled from a community tap or standpipe, often through an illegal connection), which held about 20-25 litres of unsafe water, giving a dosage of about 2mg/L free chlorine. During the trial period water samples were tested at 3 x 10-day period for free residual chlorine levels and faecal coliform counts at all households. About 65.7% of children were reported to be free from diarrhoea during the trial period, there was a strong association between "under-chlorinated" water (<0.5mg/L residual free chlorine) and reported diarrhoea incidences. Survey analysis during the pilot trial concluded that 70% of mothers were not aware that health improvements were related to water supply and sanitation. Keywords: AquatabsTM, Diarrhoea, Low income urban community. DOI: 10.3329/bjsir.v44i2.3679 Bangladesh J. Sci. Ind. Res. 44(2), 233-240, 2009

scholarly journals Chlorine disinfection facilitates natural transformation through ROS-mediated oxidative stress

2021 ◽  
Author(s):  
Shuai Zhang ◽  
Yue Wang ◽  
Ji Lu ◽  
Zhigang Yu ◽  
Hailiang Song ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Resistance Genes ◽  
Natural Transformation ◽  
Membrane Damage ◽  
Antibiotic Resistance Genes ◽  
Free Chlorine ◽  
Water Disinfection ◽  
Resistant Bacteria ◽  
Residual Chlorine ◽  
Acinetobacter Baylyi

AbstractThe bacterial infection that involves antimicrobial resistance is a rising global threat to public health. Chlorine-based water disinfection processes can inactivate antibiotic resistant bacteria. However, at the same time, these processes may cause the release of antibiotic resistance genes into the water as free DNA, and consequently increase the risk to disseminate antibiotic resistance via natural transformation. Presently, little is known about the contribution of residual chlorine affecting the transformation of extracellular antibiotic resistance genes (ARGs). This study investigates whether chloramine and free chlorine promote the transformation of ARGs and how this may occur. We reveal that both chloramine and free chlorine, at practically relevant concentrations, significantly stimulated the transformation of plasmid-encoded ARGs by the recipient Acinetobacter baylyi ADP1, by up to a 10-fold increase. The underlying mechanisms underpinning the increased transformations were revealed. Disinfectant exposure induced a series of cell responses, including increased levels of reactive oxygen species (ROS), bacterial membrane damage, ROS-mediated DNA damage, and increased stress response. These effects thus culminated in the enhanced transformation of ARGs. This promoted transformation was observed when exposing disinfectant-pretreated A. baylyi to free plasmid. In contrast, after pretreating free plasmid with disinfectants, the transformation of ARGs decreased due to the damage of plasmid integrity. These findings provide important insight on the roles of disinfectants affecting the horizontal transfer of ARGs, which could be crucial in the management of antibiotic resistance in our water systems.

scholarly journals Quantification of Hypochlorite in Water Using the Nutritional Food Additive Pyridoxamine

Water ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 3616
Author(s):  
Kamilla M. S. Kaarsholm ◽  
Argyro Kokkoli ◽  
Eleni Keliri ◽  
Paul D. Mines ◽  
Maria G. Antoniou ◽  
...  
Keyword(s):  
Absorption Maximum ◽  
Potable Water ◽  
Colorimetric Method ◽  
Fluorescence Emission ◽  
Industrial Applications ◽  
Food Additive ◽  
Free Chlorine ◽  
Negative Slope ◽  
Residual Chlorine ◽  
Limit Of Quantification

Chlorine is a widely used disinfectant and oxidant used for an array of municipal and industrial applications, including potable water, swimming pools, and cleaning of membranes. The most popular method to verify the concentration of free chlorine is the colorimetric method based on DPD (N, N-diethyl-p-phenylenediamine), which is fast and reasonably cheap, but DPD and its product are potentially toxic. Therefore, a novel, environmentally friendly colorimetric method for the quantification of residual chlorine based on the food additive pyridoxamine (4-(aminomethyl)-5-(hydroxymethyl)-2-methylpyridin-3-ol) was investigated. Pyridoxamine is a B6 vitamin with an absorption maximum at 324 nm and fluorescence emission at 396 nm. Pyridoxamine reacts rapidly and selectively with free chlorine, resulting in a linear decrease both in absorbance and in emission, giving therefore calibration curves with a negative slope. The pyridoxamine method was successfully applied for the quantification of free chlorine from 0.2 to 250 mg/L. Using 1 cm cuvettes, the limit of quantification was 0.12 mg Cl2/L. The pyridoxamine and the DPD methods were applied to actual environmental samples, and the deviation between results was between 4% and 9%. While pyridoxamine does not react with chloramine, quantification of monochloramine was possible when iodide was added, but the reaction is unfavourably slow.

scholarly journals Unchartered waters: the unintended impacts of residual chlorine on water quality and biofilms

2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Katherine E. Fish ◽  
Nik Reeves-McLaren ◽  
Stewart Husband ◽  
Joby Boxall
Keyword(s):  
Water Quality ◽  
Drinking Water ◽  
Distribution Systems ◽  
Water Distribution ◽  
Internal Surface ◽  
Free Chlorine ◽  
Residual Chlorine ◽  
Water Safety ◽  
Internal Surface Area ◽  
Drinking Water Distribution Systems

Abstract Disinfection residuals in drinking water protect water quality and public heath by limiting planktonic microbial regrowth during distribution. However, we do not consider the consequences and selective pressures of such residuals on the ubiquitous biofilms that persist on the vast internal surface area of drinking water distribution systems. Using a full scale experimental facility, integrated analyses were applied to determine the physical, chemical and biological impacts of different free chlorine regimes on biofilm characteristics (composition, structure and microbiome) and water quality. Unexpectedly, higher free chlorine concentrations resulted in greater water quality degredation, observable as elevated inorganic loading and greater discolouration (a major cause of water quality complaints and a mask for other failures). High-chlorine concentrations also reduced biofilm cell concentrations but selected for a distinct biofilm bacterial community and inorganic composition, presenting unique risks. The results challenge the assumption that a measurable free chlorine residual necessarily assures drinking water safety.

Evaluation of free and residual chlorine in drinking water of the district of Pativilca - Barranca

2018 ◽  
Vol 2 (1) ◽  
pp. 16
Author(s):  
Ronald Rodriguez ◽  
Nicodemo Jamanca ◽  
Johnny Gomero ◽  
Hector Castro ◽  
Santos Celis
Keyword(s):  
Drinking Water ◽  
Environmental Health ◽  
Free Chlorine ◽  
Residual Chlorine ◽  
Chemical Quality ◽  
Ministry Of Health ◽  
Minimum Requirement ◽  
Permissible Limits ◽  
Sampling Points

Samples were taken during one month in 12 areas of the district of Pativilca. Physicochemical analyses were performed by free chlorine and combined chlorine photometry methods. The results show that free and total chlorine have values below the maximum permissible limits, finding that 66.7% of the sampling points in the district of Pativilca do not comply with the minimum requirement of chlorine given by the General Directorate of Environmental Health of the Ministry of Health. The chemical quality of drinking water in the district of Pativilca, on average, is not within the standards assigned for free chlorine.

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