Assessing the performances of on-line analyzers can greatly improve free chlorine monitoring in drinking water

2022 ◽  
Author(s):  
Nathalie Guigues ◽  
Julien Chabrol ◽  
Pierre Lavaud ◽  
Sandrine Raveau ◽  
Jérémie Magar ◽  
...  
Keyword(s):  
Drinking Water ◽  
Free Chlorine ◽  
On Line

A micromachined electrochemical sensor for free chlorine monitoring in drinking water

2006 ◽  
Vol 53 (4-5) ◽  
pp. 403-410 ◽  
Author(s):  
A. Mehta ◽  
H. Shekhar ◽  
S.H. Hyun ◽  
S. Hong ◽  
H.J. Cho
Keyword(s):  
Drinking Water ◽  
Low Cost ◽  
Free Chlorine ◽  
Stable Operation ◽  
Chlorination Process ◽  
Transparent Substrate ◽  
On Line ◽  
Flow Through ◽  
Drinking Water Purification ◽  
On Chip

In this work, we designed, fabricated and tested a disposable, flow-through amperometric sensor for free chlorine determination in water. The sensor is based on the principle of an electrochemical cell. The substrate, as well as the top microfluidic layer, is made up of a polymer material. The advantages include; (a) disposability from low cost; (b) stable operation range from three-electrode design; (c) fluidic interconnections that provide on line testing capabilities; and (d) transparent substrate which provides for future integration of on-chip optics. The sensor showed a good response and linearity in the chlorine concentration ranging from 0.3 to 1.6 ppm, which applies to common chlorination process for drinking water purification.

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

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

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

2007 ◽  
Vol 55 (5) ◽  
pp. 161-168 ◽  
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.

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.

Identification of Cationic Herbicides in Deionized Water, Municipal Tap Water, and River Water by Capillary Isotachophoresis/On-Line Raman Spectroscopy

1997 ◽  
Vol 51 (9) ◽  
pp. 1394-1399 ◽  
Author(s):  
Patrick A. Walker ◽  
Jeremy M. Shaver ◽  
Michael D. Morris
Keyword(s):  
Drinking Water ◽  
River Water ◽  
Electrolyte Solution ◽  
Tap Water ◽  
Deionized Water ◽  
Capillary Isotachophoresis ◽  
Raman Spectroscopic ◽  
River Water Samples ◽  
On Line ◽  
Detection Window

Isotachophoresis (ITP), coupled with Raman spectroscopic detection, is used to separate and identify two cationic herbicides, paraquat and diquat, in spiked deionized water, municipal drinking water, and river water samples. On-line preconcentration is achieved with the use of field-amplified injection into a 0.03–0.1 M H2SO4 or Na2SO4 leading electrolyte solution, and isotachophoresis is achieved with the use of a 0.03–0.1 M tris(hydroxymethyl)—aminomethane (Tris) trailing electrolyte solution. The herbicides are concentrated to above 10−3 M at the detection window, allowing measurement of Raman spectra with 1-s integration windows. Spectra of the herbicides are obtained from solutions at initial concentrations in deionized water at 3.5 × 10−7 M (90 ppb) paraquat/5.8 × 10−8 M (20 ppb) diquat, from drinking water initially at 1.3 × 10−6 M (335 ppb) paraquat/1.0 × 10−6 M (360 ppb) diquat, and river water initially at 5.0 × 10−6 M (1.3 ppm) paraquat and 3.0 × 10−6 M (1.0 ppm) diquat. The utility of correlation to identify the presence of analytes and of factor analysis to recover spectra from solutions at low initial concentrations of the herbicides is demonstrated.

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

2017 ◽  
Vol 18 (2) ◽  
pp. 391-398 ◽  
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.

scholarly journals Assessment of the Legionnaires’ disease outbreak in Flint, Michigan

2018 ◽  
Vol 115 (8) ◽  
pp. E1730-E1739 ◽  
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.

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

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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