scholarly journals Modelling the Influence of Evaporation on Residual Chlorine in Water Storage Tanks Using CFD

2021 ◽  
Vol 3 (1) ◽  
pp. 33-49
Author(s):  
John Tulirinya ◽  
Richard O Awichi ◽  
Fulgensia M Kamugisha ◽  
Moses Nagulama
Keyword(s):  
Distribution Systems ◽  
Water Distribution ◽  
Water Storage ◽  
Limiting Factors ◽  
Residual Chlorine ◽  
Storage Tanks ◽  
Cfd Modelling ◽  
Bulk Fluid ◽  
Water Treatment Process ◽  
Demand Fluctuations

Water storage tanks are usually utilized in water distribution systems (WDS) to meet the water demand fluctuations. Chlorine is the most common disinfectant used to disinfect water supplies. However, variations in the rate of chlorine decay in these storage tanks are one of the greatest limiting factors in ensuring adequate water treatment process and giving guarantee to its efficiency. These variations could be due to some inadequately tested mechanisms of chlorine reactions in bulk fluid, chlorine reactions with storage tank walls, and natural evaporation. This study presents Computational Fluid Dynamics (CFD) modelling approach to assess the influence of evaporation on residual chlorine in water storage tanks. Findings indicate that an increase in the evaporation rate accelerates the rate at which residual chlorine is lost. It is concluded that temperature is the main factor influencing evaporation, which in turn causes the disappearance of residual chlorine within the water storage tanks.

scholarly journals Water-Transmitted Fungi Are Involved in Degradation of Concrete Drinking Water Storage Tanks

2021 ◽  
Vol 9 (1) ◽  
pp. 160
Author(s):  
Monika Novak Babič ◽  
Nina Gunde-Cimerman
Keyword(s):  
Drinking Water ◽  
Distribution Systems ◽  
Water Distribution ◽  
Building Materials ◽  
Water Storage ◽  
Storage Tanks ◽  
Emerging Pathogens ◽  
Oligotrophic Water ◽  
Materials Used

Global warming, globalization, industrialization, and the rapidly growing population at present increasingly affect the production of safe drinking water. In combination with sustainable bio-based or recycled materials, used for water distribution systems, these factors promote emerging pathogens, including fungi. They can proliferate in oligotrophic water systems, affect the disinfection process, degrade building materials, and cause diseases in humans. In this study, we explored fungal-based degradation of modern concrete water storage tanks and the presence of fungi in chlorinated drinking water at the entrance and exit of the tanks. The degradation potential of isolated 52 fungal strains and their growth at different oligotrophic conditions was tested in vitro. Forty percent of strains grew at extremely oligotrophic conditions, and 50% classified as aerophilic. Two-thirds of tested strains produced acids, with Penicillium strains as the best producers. Only 29.7% of the strains were able to grow at 37 °C, and none of them was isolated from drinking water at consumers’ taps. Although not yet part of the guidelines for building materials in contact with drinking water, fungi should be taken into consideration in case of visible degradation. Their number of consumers’ endpoints should be checked to exclude possible health risks for consumers.

scholarly journals Trihalomethanes formation in Iranian water supply systems: predicting and modeling

2015 ◽  
Vol 13 (3) ◽  
pp. 859-869 ◽  
Author(s):  
Ali Akbar Babaei ◽  
Leila Atari ◽  
Mehdi Ahmadi ◽  
Kambiz Ahmadiangali ◽  
Mirzaman Zamanzadeh ◽  
...  
Keyword(s):  
Drinking Water ◽  
Water Temperature ◽  
Distribution Systems ◽  
Water Distribution ◽  
Pearson Correlation ◽  
Multiple Linear Regression Model ◽  
Residual Chlorine ◽  
Water Supply Systems ◽  
Drinking Water Distribution Systems ◽  
Bromide Ion

Trihalomethanes (THMs) were the first disinfection by-products discovered in drinking water and are classified as probable carcinogens. This study measures and models THMs formation at two drinking water distribution systems (WDS1 and WDS2) in Ahvaz City, Iran. The investigation was based on field-scale investigations and an intensive 36-week sampling program, from January to September 2011. The results showed total THM concentrations in the range 17.4–174.8 μg/L and 18.9–99.5 μg/L in WDS1 and WDS2, respectively. Except in a few cases, the THM concentrations in WDS1 and WDS2 were lower than the maximum contaminant level values. Using two-tailed Pearson correlation test, the water temperature, dissolved organic carbon, UV254, bromide ion (Br−), free residual chlorine, and chlorine dose were identified as the significant parameters for THMs formation in WDS2. Water temperature was the only significant parameter for THMs formation in WDS1. Based on the correlation results, a predictive model for THMs formation was developed using a multiple regression approach. A multiple linear regression model showed the best fit according to the coefficients of determination (R2) obtained for WDS1 (R2 = 0.47) and WDS2 (R2 = 0.54). Further correlation studies and analysis focusing on THMs formation are necessary to assess THMs concentration using the predictive models.

Influence factors of organic compounds leaching from PE pipes and the potential toxic effects on E. coli and rat C6 glioma cell

2015 ◽  
Vol 16 (2) ◽  
pp. 402-409 ◽  
Author(s):  
Jingqing Liu ◽  
Hongxi Peng ◽  
Shengwei Tan ◽  
Jianmin Wu ◽  
Hamid Bastani ◽  
...  
Keyword(s):  
Water Quality ◽  
Drinking Water ◽  
Glioma Cell ◽  
Distribution Systems ◽  
Water Distribution ◽  
Influence Factors ◽  
C6 Glioma ◽  
Residual Chlorine ◽  
C6 Glioma Cell ◽  
Rat C6 Glioma

Water quality safety is always a hot topic. Recently there has been a great increase in the use of polyethylene (PE) pipes in drinking water distribution systems in China. Some organics can leach from PE pipes into drinking water, which is undoubtedly harmful for consumers. In this study, potential organics leaching from two Chinese brands of PE pipe were investigated in order to determine the potential risk to both consumers and water quality. Their released amounts are characterized by UV254 instead of total organic carbon (TOC). Organics are identified by means of gas chromatography coupled with mass spectrometry (GC-MS). Influencing factors such as types of water, time, pH, residual chlorine are discussed. The cytotoxicity of leaching organics is first put forward in this study, and rat C6 glioma cell is used to assess the effect of leaching organics; the increasing dosage of soaking solution negatively affects morphology and relative viability of rat C6 glioma cell. The results show that residual chlorine, time and temperature have a positive effect on organics release, while pH plays an opposite role.

Fungi from Potable Water: Interaction with Chlorine and Engineering Effects

1988 ◽  
Vol 20 (11-12) ◽  
pp. 153-159 ◽  
Author(s):  
William D. Rosenzweig ◽  
Wesley O. Pipes
Keyword(s):  
Water Samples ◽  
Distribution Systems ◽  
Water Distribution ◽  
Potable Water ◽  
Fungal Spores ◽  
Water Distribution Systems ◽  
Water Systems ◽  
Storage Tanks ◽  
Water Interaction ◽  
Low Concentrations

In recent years various types of imperfect fungi have been isolated from water systems. Fungal spores and mycelia can be inactivated by low concentrations of chlorine in the laboratory but survive in some habitats in water distribution systems. This report describes a field study which provides evidence that some types of fungi are able to grow in water distribution systems. Replicate samples from private residences were used to demonstrate that fungal densities are sometimes much greater than the levels which could be explained by adventitious spores. The microbiological content of water samples from fire hydrants was often significantly different from that of water samples from nearby private residences. The treated water input to distribution systems was found to be significantly lower in fungus content than water from private residences. Elevated storage tanks open to the atmosphere appear to be significant sources of fungal input to some systems.

scholarly journals Analytical Solutions to Conservative and Non-Conservative Water Quality Constituents in Water Distribution System Storage Tanks

Water ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 3502
Author(s):  
Biniam Abrha ◽  
Avi Ostfeld
Keyword(s):  
Water Quality ◽  
Distribution System ◽  
Distribution Systems ◽  
Water Distribution ◽  
Compartment Model ◽  
Storage Tanks ◽  
Water Quality Simulation ◽  
Negative Impacts ◽  
Critical Components

Water storage tanks are one of the primary and most critical components of water distribution systems (WDSs), which aim to manage water supply by maintaining pressure. In addition, storage provides a surplus source of water in case of an emergency. To gain the mentioned advantages, storage tanks are incorporated in most WDSs. Despite these advantages, storage can also pose negative impacts on water quality, thereby affecting water utilities. Water quality problems are a result of longer residency times and inadequate water mixing. This study aimed to construct a model of a tank’s water quantity and quality by formulating and solving governing equations based on inlet/outlet configurations and processes that influence the movement of water and chemical substances inside it. We used a compartment model to characterize the mixing behavior inside a tank. A water quality simulation model with different compartment arrangements was explored for extended filling and draining of storage, which was further validated using a previously published case study.

Risk-based framework for optimizing residual chlorine in large water distribution systems

2017 ◽  
Vol 189 (7) ◽  
Author(s):  
Muhammad Nadeem Sharif ◽  
Ashraf Farahat ◽  
Husnain Haider ◽  
Muhammad A. Al-Zahrani ◽  
Manuel J. Rodriguez ◽  
...  
Keyword(s):  
Distribution Systems ◽  
Water Distribution ◽  
Water Distribution Systems ◽  
Residual Chlorine ◽  
Large Water

scholarly journals Automated parameter optimization of a water distribution system

2012 ◽  
Vol 15 (1) ◽  
pp. 71-85 ◽  
Author(s):  
Maikel Méndez ◽  
José A. Araya ◽  
Luís D. Sánchez
Keyword(s):  
Parameter Space ◽  
Parameter Optimization ◽  
Distribution System ◽  
Water Distribution ◽  
Water Distribution System ◽  
Water Storage ◽  
Operating Conditions ◽  
Observation Data ◽  
Storage Tanks ◽  
Parameter Estimator

The hydraulic model EPANET was applied and calibrated for the water distribution system (WDS) of La Sirena, Colombia. The Parameter ESTimator (PEST) was used for parameter optimization and sensitivity analysis. Observation data included levels at water storage tanks and pressures at monitoring nodes. Adjustable parameters were grouped into different classes according to two different scenarios identified as constrained and unconstrained. These scenarios were established to evaluate the effect of parameter space size and compensating errors over the calibration process. Results from the unconstrained scenario, where 723 adjustable parameters were declared, showed that considerable compensating errors are introduced into the optimization process if all parameters were open to adjustment. The constrained scenario on the other hand, represented a more properly discretized scheme as parameters were grouped into classes of similar characteristics and insensitive parameters were fixed. This had a profound impact on the parameter space as adjustable parameters were reduced to 24. The constrained solution, even when it is valid only for the system's normal operating conditions, clearly demonstrates that Parallel PEST (PPEST) has the potential to be used in the calibration of WDS models. Nevertheless, further investigation is needed to determine PPEST's performance in complex WDS models.

scholarly journals Dynamics of Biofilm Regrowth in Drinking Water Distribution Systems

2016 ◽  
Vol 82 (14) ◽  
pp. 4155-4168 ◽  
Author(s):  
I. Douterelo ◽  
S. Husband ◽  
V. Loza ◽  
J. Boxall
Keyword(s):  
Drinking Water ◽  
Distribution Systems ◽  
Water Distribution ◽  
Water Distribution Systems ◽  
Influential Factors ◽  
Residual Chlorine ◽  
Water Supply Systems ◽  
Drinking Water Distribution Systems ◽  
Drinking Water Distribution ◽  
Biofilm Development

ABSTRACTThe majority of biomass within water distribution systems is in the form of attached biofilm. This is known to be central to drinking water quality degradation following treatment, yet little understanding of the dynamics of these highly heterogeneous communities exists. This paper presents original information on such dynamics, with findings demonstrating patterns of material accumulation, seasonality, and influential factors. Rigorous flushing operations repeated over a 1-year period on an operational chlorinated system in the United Kingdom are presented here. Intensive monitoring and sampling were undertaken, including time-series turbidity and detailed microbial analysis using 16S rRNA Illumina MiSeq sequencing. The results show that bacterial dynamics were influenced by differences in the supplied water and by the material remaining attached to the pipe wall following flushing. Turbidity, metals, and phosphate were the main factors correlated with the distribution of bacteria in the samples. Coupled with the lack of inhibition of biofilm development due to residual chlorine, this suggests that limiting inorganic nutrients, rather than organic carbon, might be a viable component in treatment strategies to manage biofilms. The research also showed that repeat flushing exerted beneficial selective pressure, giving another reason for flushing being a viable advantageous biofilm management option. This work advances our understanding of microbiological processes in drinking water distribution systems and helps inform strategies to optimize asset performance.IMPORTANCEThis research provides novel information regarding the dynamics of biofilm formation in real drinking water distribution systems made of different materials. This new knowledge on microbiological process in water supply systems can be used to optimize the performance of the distribution network and to guarantee safe and good-quality drinking water to consumers.

Remodeling Techniques of Water Storage Tanks and Residual Chlorine Remaining Devices

2007 ◽  
Vol 544-545 ◽  
pp. 625-628
Author(s):  
Seog Ku Kim ◽  
Hyun Dong Lee ◽  
Pill Jae Kwak ◽  
So Jung Kim ◽  
Seong Ho Hong ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Water Storage ◽  
Chlorine Concentration ◽  
Mixing Efficiency ◽  
Residual Chlorine ◽  
Feed Water ◽  
Water Tank ◽  
Storage Tanks ◽  
Inlet Pipe ◽  
Service Water

We developed the remodeling techniques of water storage tanks and the residual chlorine remaining devices. Eco-TIR((Total Internal Remodeling) is remodeling technique that cover the inside wall of concrete tank with SMC(Sheet Mold Compound) Block. Eco-SL(Stainless steel Lining) and Eco-GS(Glass sheet) is similar to Eco-TIR(Total Internal Remodeling) but stainless steel or glass tile is substituted for SMC block as a cover material. We tested the residual chlorine remaining devices and the results are as follows. First, it was estimated that mixing efficiency is increased if inflow energy to the water tank is used in the results of variation of residual chlorine concentration. Secondly, result showed that the removal percent of residual chlorine concentration was up to 90% by using ACF filter and feed water of high residual chlorine concentration can be controlled to 0.2mg/L〜0.4mg/L by using ACF and by-pass of inflow to the water tank. Also, in the water tank inlet pipe of 3-ways out using inflow energy is more effective in mixing than conventional inlet pipe. It is expected to enhance the safety of service water and management efficiency by applying mentioned techniques properly.

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