scholarly journals Network Model Analysis of Residual Chlorine to Reduce Disinfection Byproducts in Water Supply Systems in Yangon City, Myanmar

Water ◽  
2021 ◽  
Vol 13 (20) ◽  
pp. 2921
Author(s):  
Nwe Nwe Zin ◽  
Shinobu Kazama ◽  
Satoshi Takizawa

In Yangon City, chlorination commenced in January 2020 to supply drinkable water; therefore, there is as yet no information on chlorine decay and DBP formation in the water supply system. This study aimed to find methods to optimize chlorine dosage in Yangon City. Onsite sampling and laboratory analyses of residual chlorine and trihalomethane (THM) formation, as well as water quality simulations, were conducted to find the chlorine decay and THM formation kinetics. Due to a high chlorine dose of 2 mg/L for both pre- and post-chlorination, disinfection was effective despite the low removal efficiency of turbidity. However, THMs were found in high levels in both treated and tap water due to the high THM formation potential of raw water. The re-contamination and/or transformation of dissolved organic matter were found in the distribution network by increases in specific ultraviolet absorption (SUVA) values and excitation-emission matrix (EEM) fluorophores, which brought about variations of THMs in the networks. The EPANET models were run assuming there to be no water leakages; it was found that the chlorine dose could be decreased to 0.8 mg/L to meet the guidelines for THMs and residual chlorine. The methods employed in this study could be also applied in other water supply systems in tropical developing countries with limited water quality monitoring data.

2018 ◽  
Vol 30 ◽  
pp. 01017
Author(s):  
Agnieszka Szuster-Janiaczyk ◽  
Piotr Zeuschner ◽  
Paweł Noga ◽  
Marta Skrzypczak

The study presents an analysis of water quality monitoring in terms of the content of heavy metals, which is conducted in three independent water supply systems in Poland. The analysis showed that the monitoring of heavy metals isn't reliable - both the quantity of tested water samples and the location of the monitoring points are the problem. The analysis of changes in water quality from raw water to tap water was possible only for one of the analysed systems and indicate a gradual deterioration of water quality, although still within acceptable limits of legal regulations.


Author(s):  
Yu.A. Novikova ◽  
I.O. Myasnikov ◽  
A.A. Kovshov ◽  
N.A. Tikhonova ◽  
N.S. Bashketova

Summary. Introduction: Drinking water is one of the most important environmental factors sustaining life and determining human health. The goal of the Russian Federal Clean Water Project is to improve drinking water quality through upgrading of water treatment and supply systems using advanced technologies, including those developed by the military-industrial complex. The most informative and reliable sources of information for assessing drinking water quality are the results of systematic laboratory testing obtained within the framework of socio-hygienic monitoring (SGM) and production control carried out by water supply organizations. The objective of our study was to formulate approaches to organizing quality monitoring programs for centralized cold water supply systems. Materials and methods: We reviewed programs and results of drinking water quality laboratory tests performed by Rospotrebnadzor bodies and institutions within the framework of SGM in 2017–2018. Results: We established that drinking water quality monitoring in the constituent entities of the Russian Federation differs significantly in the number of monitoring points (566 in the Krasnoyarsk Krai vs 10 in Sevastopol) and measured indicators, especially sanitary and chemical ones (53 inorganic and organic substances in the Kemerovo Region vs one indicator in the Amur Region). Discussion: For a more complete and objective assessment of drinking water quality in centralized cold water supply systems, monitoring points should be organized at all stages of water supply with account for the coverage of the maximum number of people supplied with water from a particular network. Thus, the number of points in the distribution network should depend, inter alia, on the size of population served. In urban settlements with up to 10,000 inhabitants, for example, at least 4 points should be organized while in the cities with more than 3,000,000 inhabitants at least 80 points are necessary. We developed minimum mandatory lists of indicators and approaches to selecting priority indices to be monitored at all stages of drinking water supply.


Water ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 806
Author(s):  
Takuya Sakomoto ◽  
Mahmood Lutaaya ◽  
Edo Abraham

Intermittent water supply networks risk microbial and chemical contamination through multiple mechanisms. In particular, in the cities of developing countries, where intrusion through leaky pipes are more prevalent and the sanitation systems coverage is low, contaminated water can be a public health hazard. Although countries using intermittent water supply systems aim to change to continuous water supply systems—for example, Kampala city is targeting to change to continuous water supply by 2025 through an expansion and rehabilitation of the pipe infrastructure—it is unlikely that this transition will happen soon because of rapid urbanisation and economic feasibility challenges. Therefore, water utilities need to find ways to supply safe drinking water using existing systems until gradually changing to a continuous supply system. This study describes solutions for improving water quality in Mukono town in Uganda through a combination of water quality monitoring (e.g., identifying potential intrusion hotspots into the pipeline using field measurements) and interventions (e.g., booster chlorination). In addition to measuring and analyses of multiple chemical and microbial water quality parameters, we used EPANET 2.0 to simulate the water quality dynamics in the transport pipeline to assess the impact of interventions.


2018 ◽  
Vol 13 (4) ◽  
pp. 958-964
Author(s):  
V. Poljak ◽  
I. Lauš

Abstract There is no current obligation in pipeline dimensioning practice to consider free residual chlorine (FRC) consumption. The only requirements are the hydraulic parameters defined by the ‘codes of practice’ and legal regulations. The objective of this paper is to give insight into the potential additional (hidden) costs that can arise when maintaining water supply systems, i.e., parts that, from the water quality aspect, can often be considered over-dimensioned. An algorithm is used to analyse FRC consumption that is implemented in EPANET 2.0 software. EPANET 2.0 is proven to be able to yield reliable descriptions of FRC consumption in parts of water supply systems. Here it is simplified for use in relation to a single pipeline as an example.


Author(s):  
VV Vasilyev ◽  
TV Ryabinina ◽  
MV Perekusihin ◽  
EV Vasilev

Introduction: Drinking water from centralized drinking water supply systems is not always safe due to its natural pollution with various chemicals and microbiological contamination occurring in the distribution system. In this regard, the role of the service exercising governmental water quality surveillance is growing. The purpose of the study was to assess the quality of drinking water and the associated health risk and to substantiate priority measures aimed at improving the quality of water in the centralized water supply systems of the region. Materials and methods: We examined the results of drinking water quality testing performed within the implementation of sanitary and epidemiological surveillance and socio-hygienic monitoring and incidence rates in morbidity of population in 27 districts of the Penza Region and the regional center for the years 2014–2019. Health risks from oral exposures to waterborne chemicals were assessed in accordance with Guidelines R 2.1.10.1920–04. The statistical relationship was studied by the correlation method. Results: We established that water quality in the centralized water supply systems fed by underground sources is determined by the chemical composition of the exploited aquifers that divide the territory of the Penza Region into four zones. The worst water quality was observed in the fourth zone where concentrations of natural iron, fluorides and boron in tap water were many times higher than their maximum permissible levels and the hazard quotient for fluorides exceeded the limit value (HQ = 2.845 for children and 1.219 for adults). In the third zone, iron posed the highest risks of diseases of mucosa and skin (HI = 0.296), the immune system (HI = 0.311), and hematopoietic system (H = 0.473) in children; we also established a strong correlation between the average annual concentration of iron in tap water and the incidence of genitourinary disorders, gastritis and duodenitis in the child population. Although the share of the population supplied with safe drinking water from centralized water supply systems increased from 86.5 % in 2014 to 89.4 % in 2019, the target set within the Regional Clean Water Project for 2019 was not achieved. Conclusion: The study results were taken into account when making additions to the Regional Clean Water Project in 2020 envisaging construction of iron removal plants and water well drilling in areas with low fluorine levels.


Author(s):  
AYu Popova ◽  
SV Kuzmin ◽  
II Mehantyev

Background. Implementation of the Federal Clean Water Project within the National Housing and Urban Environment Project was based on the results of numerous health studies conducted within the framework of functioning of the interdepartmental system of public health monitoring and introduction of the risk-based approach into sanitary and epidemiological surveillance. In this regard, there was a need to develop a comprehensive approach to securing safety of drinking and recreational water use and assessing efficiency of implemented solutions. Objective. To assess efficiency of implementation of a system approach to ensuring safety of public drinking and recreational water use on the example of the Voronezh Region. Materials and methods. The study included laboratory testing of water quality in places of recreational water usage, drinking water quality assessment followed by a health risk assessment, a comprehensive evaluation of the extent of sanitary and epidemiological problems in drinking water supply systems, an online questionnaire-based survey of regional residents on tap water quality, a correlation analysis to establish the relationship between population health and water quality, and experimental studies to assess migration of organic compounds from polymer containers into bottled drinking water. Results. Challenges of recreational water use are associated with poor quality of surface water in terms of chemical (ammonium ion, nitrates, phosphates, and biochemical oxygen demand) and microbiological water quality parameters. Priority indices of drinking water quality in centralized water supply systems include the contents of nitrates, fluorine, boron, and iron, which are unacceptable in terms of non-carcinogenic risk (HQ > 1). In disadvantaged areas, water quality in centralized drinking water supply systems is considered “extremely poor”. The online survey demonstrated that the majority of the population (30.7 %) prefers to use water filter jugs to treat tap water. We observed significant correlations between the quality of tap and surface waters and disease incidence rates in the population. We also obtained new data on migration of organic compounds from polymer containers intended for drinking water storage and bottling in case of storage temperature excursions. Conclusion. Our findings served as the basis for the proposed algorithm of implementing a system approach to securing safety of recreational and drinking water use and for evaluating the effectiveness of implemented solutions.


2013 ◽  
Vol 16 (3) ◽  
pp. 690-709 ◽  
Author(s):  
Angeliki Aisopou ◽  
Ivan Stoianov ◽  
Nigel Graham ◽  
Bryan Karney

This paper investigates the impact of the dynamic hydraulic conditions on the kinetics of chlorine decay in water supply systems. A simulation framework has been developed for the scale-adaptive hydraulic and chlorine decay modelling under steady- and unsteady-state flows. An unsteady decay coefficient is defined which depends upon the absolute value of shear stress and the rate of change of shear stress for quasi-unsteady and unsteady-state flows. By coupling novel instrumentation technologies for continuous hydraulic monitoring and water quality sensors for in-pipe water quality sensing a pioneering experimental and analytical investigation was carried out in a water transmission main. The results were used to model monochloramine decay and these demonstrate that the dynamic hydraulic conditions have a significant impact on water quality deterioration. The spatial and temporal resolution of experimental data provides new insights for the near real-time modelling and management of water quality as well as highlighting the uncertainty and challenges of accurately modelling the loss of disinfectant in water supply networks.


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