scholarly journals Decay of Free Residual Chlorine in Wells Water of Northern Brazil

Water ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 992
Author(s):  
Taise Ferreira Vargas ◽  
Célia Ceolin Baía ◽  
Tatiana Lemos da Silva Machado ◽  
Caetano Chang Dórea ◽  
Wanderley Rodrigues Bastos
Keyword(s):  
Free Chlorine ◽  
Residual Chlorine ◽  
Decay Kinetics ◽  
Total Consumption ◽  
Tube Wells ◽  
Brazilian Amazon Region ◽  
Dug Wells ◽  
Northern Brazil ◽  
Chlorine Decay ◽  
Free Residual Chlorine

The concentration of chlorine in water declines as it reacts with various substances, causing decay of the residual free chlorine until its total consumption. In light of the typical characteristics of the water from protected dug wells and tube wells, this study aimed to evaluate the decay kinetics of free chlorine in the water of alternative individual supply (AIS) solutions used in the city of Porto Velho in the Brazilian Amazon region. The free chlorine decay constant in the water was evaluated by “bottle tests,” applying a first-order model. According to the results, the type of well and initial chlorine concentration significantly influences the free chlorine decay speed. The water samples from the tubular wells had lower chlorine demand levels, attributed to their better water quality. The simulation of the residual chlorine decay in the different supply sources is an important tool to support safe disinfection processes.

Application of two approaches to model chlorine residuals in Severn Trent Water Ltd (STW) distribution systems

1997 ◽  
Vol 36 (5) ◽  
pp. 317-324 ◽  
Author(s):  
M.J. Rodriguez ◽  
J.R. West ◽  
J. Powell ◽  
J.B. Sérodes
Keyword(s):  
Distribution System ◽  
Distribution Systems ◽  
Treatment Plant ◽  
Residual Chlorine ◽  
Ann Model ◽  
Order Model ◽  
First Order ◽  
Chlorine Decay ◽  
Artificial Neural Network Ann ◽  
Key Parameter

Increasingly, those who work in the field of drinking water have demonstrated an interest in developing models for evolution of water quality from the treatment plant to the consumer's tap. To date, most of the modelling efforts have been focused on residual chlorine as a key parameter of quality within distribution systems. This paper presents the application of a conventional approach, the first order model, and the application of an emergent modelling approach, an artificial neural network (ANN) model, to simulate residual chlorine in a Severn Trent Water Ltd (U.K.) distribution system. The application of the first order model depends on the adequate estimation of the chlorine decay coefficient and the travel time within the system. The success of an ANN model depends on the use of representative data about factors which affect chlorine evolution in the system. Results demonstrate that ANN has a promising capacity for learning the dynamics of chlorine decay. The development of an ANN appears to be justifiable for disinfection control purposes, in cases when parameter estimation within the first order model is imprecise or difficult to obtain.

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.

Dependency of bulk chlorine decay rates on flow velocity in water distribution networks

2003 ◽  
Vol 3 (1-2) ◽  
pp. 209-214 ◽  
Author(s):  
J. Menaia ◽  
S.T. Coelho ◽  
A. Lopes ◽  
E. Fonte ◽  
J. Palma
Keyword(s):  
Drinking Water ◽  
Flow Velocity ◽  
Distribution Systems ◽  
Distribution Networks ◽  
Decay Rates ◽  
Decay Kinetics ◽  
Decay Rate Constant ◽  
Chlorine Residual ◽  
Chlorine Decay ◽  
Static Conditions

Understanding chlorine residual decay kinetics and the factors that influence them are essential for such current tasks as siting chlorination facilities, dosage optimisation, choice of sampling locations and frequencies, and general design and operational control of drinking water networks, increasingly accomplished with the help of simulation models. Available constants for bulk chlorine decay are typically determined under static conditions. However, as for all fast reactions in water flows, chlorine consumption rates in drinking water pipes may be influenced by the existing mixing regimes, a function of flow turbulence, which is primarily controlled by flow velocity and pipe diameter. Flow velocities vary greatly in space and time in water transmission and distribution systems; pipe diameters are seldom uniform. Although both variables are readily available in the currently available network analysis simulators that implement chlorine models, such variations are not accounted for. Instead, a single preset decay rate constant is generally used for describing chlorine residual consumption throughout an entire system. In addition to highlighting how negligible PVC pipe wall chlorine consumption is, as such, this paper presents experimental evidence of a significant correlation between pipe flow velocity and bulk chlorine decay rates, and proposes a simple but effective approach to implement this dependency in current simulators.

scholarly journals Point-of-use water chlorination among urban and rural households with under-five-year children: a comparative study in Kersa Health and Demographic Surveillance Site, Eastern Ethiopia

2018 ◽  
Vol 8 (3) ◽  
pp. 468-480 ◽  
Author(s):  
Abraham Geremew ◽  
Bezatu Mengistie ◽  
Esayas Alemayehu ◽  
Daniele Susan Lantagne ◽  
Jonathan Mellor ◽  
...  
Keyword(s):  
Rural Areas ◽  
Urban Areas ◽  
Residual Chlorine ◽  
Eastern Ethiopia ◽  
Under Five ◽  
Demographic Surveillance Site ◽  
Surveillance Site ◽  
Point Of Use ◽  
Water Chlorination ◽  
Free Residual Chlorine

Abstract Point-of-use water chlorination is one of the most effective means to prevent diarrhea in under-five children although challenges remain in its adoption and effective use. In Ethiopia, evidence of point-of-use water chlorination among households with under-five children in rural and urban settings that is verified with water testing is scarce. A comparative cross-sectional study was conducted among urban and rural households with under-five child in Kersa Health and Demographic Surveillance Site, Eastern Ethiopia from June to August, 2016. Data were collected from a caregiver of systematically selected households and analyzed using multivariable logistic regression. A total of 1,912 households were included in the analysis with a 96.5% response rate. In rural areas, 4.6% of caregivers were reportedly chlorinating water at point-of-use and 1.2% were confirmed with free residual chlorine. In urban areas, 17.1% of caregivers were reportedly chlorinating water and 6.6% were confirmed to have free residual chlorine. In two settings, caregivers' point-of-use water chlorination was associated with chlorine taste and water quality perception. Inaccessibility to treatment products in rural areas and use of bottled water in urban areas were among the reasons to discontinue point-of-use water chlorination. Behavior changing interventions with proper distribution and marketing is needed for sustainable point-of-use chlorination.

scholarly journals Prevalence and risk factors associated with Campylobacter among layer farms

2018 ◽  
Vol 8 (1) ◽  
Author(s):  
Mohammad Q. Al-Natour ◽  
Akram R. Al-Aboudi ◽  
Musa A. Alshehabat ◽  
MT K. Tamimi
Keyword(s):  
Risk Factors ◽  
Stocking Density ◽  
Occurrence Rate ◽  
Residual Chlorine ◽  
Public Health Importance ◽  
Factors Associated ◽  
Poultry Products ◽  
Food Borne ◽  
Potential Risk Factors ◽  
Free Residual Chlorine

Campylobacter jejuni is an important food-borne pathogen. The main source of this pathogen is poultry and poultry products. Poultry farms of low biosecurity level plays major role in disseminating this pathogen. The objectives of this study were to investigate the occurrence of Campylobacter and identify potential risk factors associated with their presence in layer farms in Northern Jordan. A total of 2524 samples from chickens, litter, water and feed were collected from 35-layer farms. Samples underwent conventional and enrichment isolation methods for Campylobacter. Confirmation was done morphologically, biochemically and by PCR typing. The flock-level prevalence of C. jejuni was 40%, 37%, 20% in chicken cloacae, drinking water and litter respectively. C. jejuni was the only confirmed isolated species. None of the feed samples revealed presence of Campylobacter. The concentration of free residual chlorine was below the recommended standard levels. The risk factors were identified using modified semi-structured questionnaire. There was no significant association between evaluated risk factors and isolation status potentially reflecting small number of study farms. The prevalence rate for C. jejuni is within commonly reported range. High stocking density, short distance between farms, improper hygienic practice and low water chlorine level seems to increase occurrence rate of Campylobacter in layer farms. Educational biosecurity programs regarding C. jejuni transmission and their public health importance needs to be established.

Organic THMs precursors removal from surface water with low TOC and high alkalinity by enhanced coagulation

2004 ◽  
Vol 4 (5-6) ◽  
pp. 103-111 ◽  
Author(s):  
L. Rizzo ◽  
V. Belgiorno ◽  
S. Meriç
Keyword(s):  
Surface Water ◽  
Drinking Water Treatment ◽  
Residual Chlorine ◽  
Enhanced Coagulation ◽  
Toc Removal ◽  
Jar Test ◽  
High Alkalinity ◽  
Surface Water Resource ◽  
Free Residual Chlorine ◽  
Residual Al

NOM removal from surface waters is needed because of potentially carcinogen compound (trihalomethane, THM) formation due to reaction between NOM and free residual chlorine used for disinfection. The stringent limits for THMs (e.g., 30 μg/l in Italy) force conventional drinking water treatment plants to increase TOC removal efficiency by enhanced coagulation. This study was performed on 17 samples taken from a surface water resource with low TOC content (<3 mg/l) and high alkalinity (190 mg as CaCO3/l) to remove TOC and other parameters (DOC, UV254, SUVA, turbidity), typically used to characterize NOM content. Four different coagulants (Al2(SO4)3·18H2O, FeCl3·6H2O, FeSO4·7H2O and PACl) were used in jar test without adding polymer as flocculant. There was no correlation between DOC and SUVA in raw and treated water. TOC removal efficiencies (15–30%) required by the USEPA D/DBPs rule were obtained using 30–50 mg/l alum, 30–50 mg/l of FeCl3, and less than 20 mg/l of PACl (as Al2O3, 10%). The use of PACl is suggested for both lesser TTHMFP and residual Al levels (<100 μg/l) occurrences without any pH adjustment.

Role of drinking water biofilms on residual chlorine decay and trihalomethane formation: An experimental and modeling study

2018 ◽  
Vol 642 ◽  
pp. 516-525 ◽  
Author(s):  
Jianeng Xu ◽  
Conghui Huang ◽  
Xiaoyang Shi ◽  
Shengkun Dong ◽  
Baoling Yuan ◽  
...  
Keyword(s):  
Drinking Water ◽  
Residual Chlorine ◽  
Chlorine Decay ◽  
Modeling Study

Modeling of THMs and HAAs Formation in Distribution System upon Chlorination

2012 ◽  
Vol 455-456 ◽  
pp. 1273-1277
Author(s):  
Rong Ma ◽  
Xi Wu Lu
Keyword(s):  
Linear Regression ◽  
Multiple Linear Regression ◽  
Ultraviolet Light ◽  
Distribution Systems ◽  
Treatment Plant ◽  
Multiple Linear Regression Model ◽  
Residual Chlorine ◽  
Free Residual Chlorine ◽  
Light Absorbance ◽  
Distribution Water

Seasonal variations of trihalomethanes (THMs) and haloacetic acids (HAAs) were investigated within distribution systems of the Yangtze river treatment plant in Nanjing City (China).The investigation was based on one year sampling program, undertaken from the fall and winter of the year 2007 to the spring and summer of the year 2008. A multiple linear regression model was developed to predict THMs and HAAs concentrations in distribution water. Routinely measured parameters including free residual chlorine, ultraviolet light absorbance at 254 nm (UV254), temperature, pH and NH3-N in distribution water was used to develop the model for the prediction of THMs and HAAs. The developed models provided satisfactory estimations of the concentrations of THMs and HAAs and the model regression coefficients of THMs and HAAs are 0.90 and 0.87, respectively. Further, the Durbin-Watson values confirm the reliability of the two models. The results indicate that variations of free residual chlorine, ultraviolet light absorbance at 254 nm (UV254), temperature, pH and NH3-N can described the formation of THMs and HAAs in distribution water by the multiple linear regression technique.

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