A Drinking Water Relevant Water Chemistry Model for the Free Chlorine and Cyanuric Acid System from 5°C to 35°C

Human activities and natural factors determine the hydrogeochemical characteristics of karst groundwaters and their use as drinking water. This study assesses the hydrogeochemical characteristics of 14 karst water sources in the Apuseni Mountains (NW Romania) and their potential use as drinking water sources. As shown by the Durov and by the Piper diagrams, the chemical composition of the waters is typical of karst waters as it is dominated by HCO3− and Ca2+, having a circumneutral to alkaline pH and total dissolved solids ranging between 131 and 1092 mg L−1. The relation between the major ions revealed that dissolution is the main process contributing to the water chemistry. Limestone and dolostone are the main Ca and Mg sources, while halite is the main Na and Cl source. The Gibbs diagram confirmed the rock dominance of the water chemistry. The groundwater quality index (GWQI) showed that the waters are of excellent quality, except for two waters that displayed medium and good quality status. The quality of the studied karst waters is influenced by the geological characteristics, mainly by the water–rock interaction and, to a more limited extent, by anthropogenic activities. The investigated karst waters could be exploited as drinking water resources in the study area. The results of the present study highlight the importance of karst waters in the context of good-quality water shortage but also the vulnerability of this resource to anthropogenic influences.

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Membrane-based colorimetric flow-injection system for online free chlorine monitoring in drinking water

Sensors and Actuators B Chemical ◽

10.1016/j.snb.2020.128905 ◽

2021 ◽

Vol 327 ◽

pp. 128905

Author(s):

Ming Zhou ◽

Tianling Li ◽

Meng Zu ◽

Shanqing Zhang ◽

Yang Liu ◽

...

Keyword(s):

Drinking Water ◽

Flow Injection ◽

Free Chlorine ◽

Injection System ◽

Flow Injection System

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Sensory aspects of drinking water in contact with epoxy lined copper pipe

Water Science & Technology ◽

10.2166/wst.2007.175 ◽

2007 ◽

Vol 55 (5) ◽

pp. 161-168 ◽

Cited By ~ 14

Author(s):

T.H. Heim ◽

A.M. Dietrich

Keyword(s):

Water Quality ◽

Drinking Water ◽

Organic Compounds ◽

Sensory Analysis ◽

Water Samples ◽

Distribution System ◽

Distribution Systems ◽

Free Chlorine ◽

Copper Pipe

Pipe relining via in situ epoxy lining is used to remediate corroded plumbing or distribution systems. This investigation examined the effects on odour, TOC, THM formation and disinfectant demand in water exposed to epoxy-lined copper pipes used for home plumbing. The study was conducted in accordance with the Utility Quick Test, a migration/leaching method for utilities to conduct sensory analysis of materials in contact with drinking water. The test was performed using water with no disinfectant and levels of chlorine and monochloramines representative of those found in the distribution system. Panelists repeatedly and consistently described a “plastic/adhesive/putty” odour in the water from the pipes. The odour intensity remained relatively constant for each of two subsequent flushes. Water samples stored in the epoxy-lined pipes showed a significant increase in the leaching of organic compounds (as TOC), and this TOC was demonstrated to react with free chlorine to form trichloromethane. Water stored in the pipes also showed a marked increase in disinfectant demand relative to the water stored in glass control flasks. A study conducted at a full scale installation at an apartment demonstrated that after installation and regular use, the epoxy lining did not yield detectable differences in water quality.

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

The Scientific World JOURNAL ◽

10.1100/tsw.2001.13 ◽

2001 ◽

Vol 1 ◽

pp. 39-43 ◽

Cited By ~ 2

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.

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Optrode Based Polymer for the Estimation of Free Chlorine

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.573.856 ◽

2014 ◽

Vol 573 ◽

pp. 856-860

Author(s):

N. Sivakamasundari ◽

N. Bharathi ◽

A.R. Neena Sruthi ◽

A. Balaji Ganesh

Keyword(s):

Cyanuric Acid ◽

Low Cost ◽

Optical Fiber Sensor ◽

Free Chlorine ◽

Continuous Exposure ◽

The Public ◽

Sensor Membrane ◽

Good Repeatability ◽

Photochemical Stability ◽

Sensing Membrane

This paper describes the construction of low cost optical fiber sensor for the measurement of free chlorine and also residuals. The granules of poly (norborene) s bound with Cyanuric acid are synthesized as polymer film and applied on glass surface, which is used as sensing membrane. The prepared sensor membrane has a good photochemical stability and it would not leach out by continuous exposure to sample solution. The film is used to measure the changes in the absorbance intensity as a result of reaction between Cyanuric acid and free chlorine. The chlorine is used for the destruction of microbiological pathogens to protect the public health from water-borne diseases. This experiment was conducted for various chlorine samples. The sensor possess good repeatability with the range from 1.0 mg/l to 9.0 mg/l with minimal response time and also shows the characteristics such as reproducibility and stable results for more than 70 samples with a period of 5 days.

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Critical Review: Propensity of Premise Plumbing Pipe Materials to Enhance or Diminish Growth of Legionella and Other Opportunistic Pathogens

Pathogens ◽

10.3390/pathogens9110957 ◽

2020 ◽

Vol 9 (11) ◽

pp. 957

Author(s):

Abraham C. Cullom ◽

Rebekah L. Martin ◽

Yang Song ◽

Krista Williams ◽

Amanda Williams ◽

...

Keyword(s):

Drinking Water ◽

Water Chemistry ◽

Legionella Pneumophila ◽

High Surface ◽

Metallic Copper ◽

Health Concern ◽

Future Research ◽

Opportunistic Pathogens ◽

Premise Plumbing ◽

Pipe Materials

Growth of Legionella pneumophila and other opportunistic pathogens (OPs) in drinking water premise plumbing poses an increasing public health concern. Premise plumbing is constructed of a variety of materials, creating complex environments that vary chemically, microbiologically, spatially, and temporally in a manner likely to influence survival and growth of OPs. Here we systematically review the literature to critically examine the varied effects of common metallic (copper, iron) and plastic (PVC, cross-linked polyethylene (PEX)) pipe materials on factors influencing OP growth in drinking water, including nutrient availability, disinfectant levels, and the composition of the broader microbiome. Plastic pipes can leach organic carbon, but demonstrate a lower disinfectant demand and fewer water chemistry interactions. Iron pipes may provide OPs with nutrients directly or indirectly, exhibiting a high disinfectant demand and potential to form scales with high surface areas suitable for biofilm colonization. While copper pipes are known for their antimicrobial properties, evidence of their efficacy for OP control is inconsistent. Under some circumstances, copper’s interactions with premise plumbing water chemistry and resident microbes can encourage growth of OPs. Plumbing design, configuration, and operation can be manipulated to control such interactions and health outcomes. Influences of pipe materials on OP physiology should also be considered, including the possibility of influencing virulence and antibiotic resistance. In conclusion, all known pipe materials have a potential to either stimulate or inhibit OP growth, depending on the circumstances. This review delineates some of these circumstances and informs future research and guidance towards effective deployment of pipe materials for control of OPs.

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Microbiological safety of a small water distribution system: evaluating potentially pathogenic bacteria using advanced sequencing techniques

Water Science & Technology Water Supply ◽

10.2166/ws.2017.091 ◽

2017 ◽

Vol 18 (2) ◽

pp. 391-398 ◽

Cited By ~ 1

Author(s):

A. M. M. Batista ◽

P. Meynet ◽

G. P. P. Garcia ◽

S. A. V. Costa ◽

J. C. Araujo ◽

...

Keyword(s):

Drinking Water ◽

Relative Abundance ◽

Distribution System ◽

Water Distribution ◽

Pathogenic Bacteria ◽

Water Distribution System ◽

Free Chlorine ◽

Intermediate Point ◽

Microbiological Safety ◽

The City

Abstract This study evaluated the microbiological safety of the water distribution system of a city in the state of Minas Gerais (Brazil), population 120,000 inhabitants. During the study, the city suffered a severe drought that had a significant impact on water availability and quality in the river that supplies water to the city. Samples (2 liters) were collected from the distribution system over a period of six months, which included wet and dry months, from three points: the point with the lowest altitude in the distribution network, the farthest point from the water treatment works, and an intermediate point. Free chlorine was measured in situ using a Hach kit. DNA was extracted using a FastDNA Spin Kit Soil (Qbiogene). Advanced sequencing techniques (Ion Torrent) were used to identify and quantify the relative abundance of potentially pathogenic bacteria present in the samples. Coliforms and Escherichia coli, indicators currently used worldwide to assess microbiological safety of drinking water, were measured on all samples using an enzyme substrate method (ONPG-MUG Colilert®). Next generation sequencing results retrieved 16SrRNA sequences of E. coli and some potentially pathogenic bacteria, even in the presence of free chlorine. Operational taxonomic units related to pathogenic bacteria were present in all samples from the drinking water distribution system (DWS) and, in general, at high relative abundance (up to 5%). A total of 19 species related to bacterial pathogens were detected. Inadequate operational practices that could affect the microbiological safety of the DWS were identified and discussed. The current paper is the first to evaluate the community of potentially pathogenic bacteria in a real DWS.

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Assessment of the Legionnaires’ disease outbreak in Flint, Michigan

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1718679115 ◽

2018 ◽

Vol 115 (8) ◽

pp. E1730-E1739 ◽

Cited By ~ 37

Author(s):

Sammy Zahran ◽

Shawn P. McElmurry ◽

Paul E. Kilgore ◽

David Mushinski ◽

Jack Press ◽

...

Keyword(s):

Drinking Water ◽

Water Supply ◽

Census Tract ◽

Water System ◽

Disease Outbreak ◽

Free Chlorine ◽

Legionnaires Disease ◽

Genesee County ◽

Flint River ◽

Boil Water Advisories

The 2014–2015 Legionnaires’ disease (LD) outbreak in Genesee County, MI, and the outbreak resolution in 2016 coincided with changes in the source of drinking water to Flint’s municipal water system. Following the switch in water supply from Detroit to Flint River water, the odds of a Flint resident presenting with LD increased 6.3-fold (95% CI: 2.5, 14.0). This risk subsided following boil water advisories, likely due to residents avoiding water, and returned to historically normal levels with the switch back in water supply. During the crisis, as the concentration of free chlorine in water delivered to Flint residents decreased, their risk of acquiring LD increased. When the average weekly chlorine level in a census tract was <0.5 mg/L or <0.2 mg/L, the odds of an LD case presenting from a Flint neighborhood increased by a factor of 2.9 (95% CI: 1.4, 6.3) or 3.9 (95% CI: 1.8, 8.7), respectively. During the switch, the risk of a Flint neighborhood having a case of LD increased by 80% per 1 mg/L decrease in free chlorine, as calculated from the extensive variation in chlorine observed. In communities adjacent to Flint, the probability of LD occurring increased with the flow of commuters into Flint. Together, the results support the hypothesis that a system-wide proliferation of legionellae was responsible for the LD outbreak in Genesee County, MI.

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Effects of residual disinfectants on the redox speciation of lead(ii)/(iv) minerals in drinking water distribution systems

Environmental Science Water Research & Technology ◽

10.1039/d0ew00706d ◽

2021 ◽

Author(s):

Sumant Avasarala ◽

John Orta ◽

Michael Schaefer ◽

Macon Abernathy ◽

Samantha Ying ◽

...

Keyword(s):

Drinking Water ◽

Reaction Kinetics ◽

Distribution Systems ◽

Water Distribution ◽

Water Distribution Systems ◽

Free Chlorine ◽

Oxidative Transformation ◽

Drinking Water Distribution Systems ◽

Drinking Water Distribution ◽

Free Bromine

This study investigated the reaction kinetics on the oxidative transformation of lead(ii) minerals by free chlorine (HOCl) and free bromine (HOBr) in drinking water distribution systems.

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