Characterization of drinking water storage tanks in Portugal

Monteiro, Laura; Pinheiro, Alexandre; Carneiro, Joana; Covas, Dídia

doi:10.4995/ia.2021.13659

Cited by 6 publications

(2 citation statements)

References 10 publications

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“…IMiST project is organized in seven main tanks: T1 -Field survey and database assembly; T2 -Lab scale studies; T3 -Numerical modelling; T4 -Full scale studies; T5 -Mixing improvement measures; T6 -Modelling of mixing in hydraulic simulators; T7 -Recommendations design, operation and rehabilitation. Results have given rise to several publications [46][47][48][49][50][51]. Relevant results attained in tasks T2-T6 are briefly presented herein.…”

Section: Introductionmentioning

confidence: 80%

Modelling of water mixing and renewal time in storage tanks

Covas,

Pinheiro,

Vaz

et al. 2022

Proceedings - 2nd International Join Conference on Water Distribution System Analysis (WDSA)& Computing and Control in the

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The current paper aims at presenting the main developments and achievement attained in research project IMiST – Improving mixing in Storage Tanks for safer water supply, funded by Fundação para a Ciencia e Tecnologia, carried out between 2018 and 2022. This project aimed at a better understanding of flow dynamics inside water supply systems’ storage tanks to find practicable solutions to improve the design and the rehabilitation and to support operation of the existing tanks. The project comprised the development of an extensive experimental programme of small-scale tests, full-scale testing in a real storage tank and advanced numerical modelling. Small-scale tests were carried out in the Laboratory of Hydraulics and Water Resources of Instituto Superior Técnico, Portugal, for different tank’s configurations and operating conditions. Two different cross-section tanks (circular and rectangular) were tested with and without interior structures (baffles) and with the inlet and outlet pipes at different locations. Three sets of experimental tests were carried out using different instrumentation to collect complementary data, namely traditional tracer tests, dye tracer tests and velocity field measurements by Particle Image Velocimetry (PIV). A methodology for assessing mixing conditions in full-scale storage tanks was developed and tested in a real tank with a rectangular cross-section and 3500 m3 capacity with inner baffles. Advanced numerical modelling using Computational Fluid Dynamics was carried out for the submerged and plunging get in a circular tank for betted understanding the velocity fields and the flow patterns. This complementary experimental and numerical modelling have allowed drawing conclusions concerning improving mixing measures, by readjusting the tank configuration (e.g., location, number and diameter of inlet/outlet pipes, jet inflow, fluctuating stored water volume and geometry) and changing operating conditions (e.g., extreme tank levels, pump scheduling). New knowledge on water storage tank hydrodynamics has been created and guidelines for upgrading tank design, rehabilitation and operation were prepared with design criteria for new tanks and measures for the improvement/rehabilitation of existing tanks in supply systems, that will be briefly summarised herein.

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Section: Introductionmentioning

confidence: 80%

Modelling of water mixing and renewal time in storage tanks

Covas,

Pinheiro,

Vaz

et al. 2022

Proceedings - 2nd International Join Conference on Water Distribution System Analysis (WDSA)& Computing and Control in the

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“…Portugal's most common drinking water storage tanks are placed in-ground, have a circular cross-section without internal baffles, and a ratio between tank diameter and water height, 0.04 < H/D T < 1.85 [40]. The nozzle is typically located above the water level (as a plunging jet) to separate the storage tank from the upstream transmission pipeline, avoiding emptying the tank if a sudden accident occurs and is not timely detected.…”

Section: Models Descriptionmentioning

confidence: 99%

Induced Circulation by Plunging and Submerged Jets in Circular Water Storage Tanks Using CFD

Martins

Covas

2022

Water

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Water circulation in storage tanks significantly impacts water quality in distribution networks since old water tends to have low residual chlorine concentrations that are insufficient to neutralize microbial regeneration. Their large capacity and long residence times result in uneven mixing, which can accelerate the disinfectant decay and the formation of potentially carcinogenic disinfection by-products. The phenomenon is strongly related to the tank inflow conditions, since there are no active mixing devices. This paper presents a comprehensive analysis of the flow dynamics in circular storage tanks using a three-dimensional computational fluid dynamics model. The main motivation is that the inflow—which mixing processes rely on—strongly influences the circulations. The numerical analysis provided includes a thorough investigation of interest in understanding flow dynamics for two inflow configurations: (i) the plunging jet modelling and comparison with published experimental data and (ii) the submerged jet as an improvement measurement for these storage tanks.

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