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18 pages, 5591 KiB

Open AccessFeature PaperArticle

Hydrodynamic and Hydrographic Modeling of Istanbul Strait

by Mehmet Melih Koşucu, Mehmet Cüneyd Demirel, V.S. Ozgur Kirca and Mehmet Özger

Processes 2019, 7(10), 710; https://doi.org/10.3390/pr7100710 - 07 Oct 2019

Cited by 4 | Viewed by 3986 | Correction

Abstract

The aim of this study is to model the hydrodynamic processes of the Istanbul Strait with its stratified flow characteristics, and calibrate the most important parameters using local and global search algorithms. For that, two open boundary conditions are defined, which are in [...] Read more.

The aim of this study is to model the hydrodynamic processes of the Istanbul Strait with its stratified flow characteristics, and calibrate the most important parameters using local and global search algorithms. For that, two open boundary conditions are defined, which are in the northern and southern parts of the Strait. Observed bathymetric, hydrographic, meteorological, and water-level data are used to set up the Delft3D-FLOW model. First, the sensitivities of the model parameters on the numerical model outputs are assessed using Parameter EStimation Tool (PEST) toolbox. Then, the model is calibrated based on the objective functions, focusing on the flow rates of the upper and lower layers. The salinity and temperature profiles of the strait are only used for model validation. The results show that the calibrated model outputs of the Istanbul Strait are reliable and consistent with the in situ measurements. The sensitivity analysis reveals that the spatial low-pass filter coefficient, horizontal eddy viscosity, Prandtl–Schmidt number, slope in log–log spectrum, and Manning roughness coefficient are most sensitive parameters affecting the flow rate performance of the model. The agreement between observed salinity profiles and simulated model outputs is promising, whereas the match between observed and simulated temperature profiles is weak, showing that the model can be improved, particularly for simulating the mixing layer. Full article

(This article belongs to the Special Issue Water Quality Modelling)

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11 pages, 808 KiB

Open AccessArticle

Leaching of Organic Toxic Compounds from PVC Water Pipes in Medina Al-Munawarah, Kingdom of Saudi Arabia

by Muhammad Mansoor Shaikh, Marlia Mohd Hanafiah and Alfarooq O. Basheer

Processes 2019, 7(10), 641; https://doi.org/10.3390/pr7100641 - 20 Sep 2019

Cited by 9 | Viewed by 10278

Abstract

It is well established that the use of synthetic material in water pipes significantly affects the quality of domestic water, especially trace organics that are leached through with the flow of water. In the present study, the migration of volatile organic compounds (VOCs) [...] Read more.

It is well established that the use of synthetic material in water pipes significantly affects the quality of domestic water, especially trace organics that are leached through with the flow of water. In the present study, the migration of volatile organic compounds (VOCs) from water pipes manufactured of polyvinyl chloride (PVC) has been investigated using static laboratory conditions and in residential areas. The contact of deionized water with various PVC pipes for three successive test periods of 24, 48, and 72 h duration has been made. Twenty water samples were collected from houses within Medina Al-Munawarah residential area and were analyzed by using solid phase extraction, followed by high resolution gas chromatography with flame ionized detector (GC-FID). The presence of carbon tetrachloride (CTC), toluene, chloroform, styrene, o-xylene, bromoform (BF), dibromomethane (DBM), cis-1,3-dichloropropane (Cis-1,3-DCP), and trans-1,3-dichloropropane (Trans-1,3-DCP) was initially confirmed. The most frequent contaminants found were DBM, CTC, and toluene that were monitored in 55%, 50%, and 45% of samples, respectively. The levels of CTC, Cis-1,3-DCP, and Trans-1,3-DCP were found to exceed the World Health Organization (WHO) limits in 50%, 20%, and 20% of samples, respectively. The migration test indicated that nine of the targeted contaminants occur in a double distilled water sample incubated in pipe in laboratory level experiment. This implies that these components are more likely to migrate from PVC pipe in home plumbing systems network. Full article

(This article belongs to the Special Issue Water Quality Modelling)

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19 pages, 2598 KiB

Open AccessArticle

Using Parallel Genetic Algorithms for Estimating Model Parameters in Complex Reactive Transport Problems

by Jagadish Torlapati and T. Prabhakar Clement

Processes 2019, 7(10), 640; https://doi.org/10.3390/pr7100640 - 20 Sep 2019

Cited by 8 | Viewed by 2609

Abstract

In this study, we present the details of an optimization method for parameter estimation of one-dimensional groundwater reactive transport problems using a parallel genetic algorithm (PGA). The performance of the PGA was tested with two problems that had published analytical solutions and two [...] Read more.

In this study, we present the details of an optimization method for parameter estimation of one-dimensional groundwater reactive transport problems using a parallel genetic algorithm (PGA). The performance of the PGA was tested with two problems that had published analytical solutions and two problems with published numerical solutions. The optimization model was provided with the published experimental results and reasonable bounds for the unknown kinetic reaction parameters as inputs. Benchmarking results indicate that the PGA estimated parameters that are close to the published parameters and it also predicted the observed trends well for all four problems. Also, OpenMP FORTRAN parallel constructs were used to demonstrate the speedup of the code on an Intel quad-core desktop computer. The parallel code showed a linear speedup with an increasing number of processors. Furthermore, the performance of the underlying optimization algorithm was tested to evaluate its sensitivity to the various genetic algorithm (GA) parameters, including initial population size, number of generations, and parameter bounds. The PGA used in this study is generic and can be easily scaled to higher-order water quality modeling problems involving real-world applications. Full article

(This article belongs to the Special Issue Water Quality Modelling)

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20 pages, 10084 KiB

Open AccessFeature PaperArticle

Novel 3-D T-Shaped Passive Micromixer Design with Helicoidal Flows

by Mahmut Burak Okuducu and Mustafa M. Aral

Processes 2019, 7(9), 637; https://doi.org/10.3390/pr7090637 - 19 Sep 2019

Cited by 23 | Viewed by 4537

Abstract

Laminar fluid flow and advection-dominant transport produce ineffective mixing conditions in micromixers. In these systems, a desirable fluid mixing over a short distance may be achieved using special geometries in which complex flow paths are generated. In this paper, a novel design, utilizing [...] Read more.

Laminar fluid flow and advection-dominant transport produce ineffective mixing conditions in micromixers. In these systems, a desirable fluid mixing over a short distance may be achieved using special geometries in which complex flow paths are generated. In this paper, a novel design, utilizing semi-circular ridges, is proposed to improve mixing in micro channels. Fluid flow and scalar transport are investigated employing Computational Fluid Dynamics (CFD) tool. Mixing dynamics are investigated in detail for alternative designs, injection, and diffusivity conditions. Results indicate that the convex alignment of semi-circular elements yields a specific, helicoidal-shaped fluid flow along the mixing channel which in turn enhances fluid mixing. In all cases examined, homogenous concentration distributions with mixing index values over 80% are obtained. When it is compared to the classical T-shaped micromixer, the novel design increases mixing index and mixing performance values by the factors of 8.7 and 3.3, respectively. It is also shown that different orientations of ridges adversely affect the mixing efficiency by disturbing the formation of helicoidal-shaped flow profile. Full article

(This article belongs to the Special Issue Water Quality Modelling)

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13 pages, 3312 KiB

Open AccessArticle

Impact Analysis of Water Quality on the Development of Construction Materials

by Hamad Farid, Muhammad Shoaib Mansoor, Syyed Adnan Raheel Shah, Nasir Mahmood Khan, Rana Muhammad Farooq Shabbir, Muhammad Adnan, Hunain Arshad, Inzmam-Ul Haq and Muhammad Waseem

Processes 2019, 7(9), 579; https://doi.org/10.3390/pr7090579 - 02 Sep 2019

Cited by 8 | Viewed by 4307

Abstract

This research dealt with the impact of the quality of the water source on the mechanical properties of construction materials. The mechanical properties of construction materials include compressive, tensile, and flexural strength. Water samples were collected from different resources, these samples were then [...] Read more.

This research dealt with the impact of the quality of the water source on the mechanical properties of construction materials. The mechanical properties of construction materials include compressive, tensile, and flexural strength. Water samples were collected from different resources, these samples were then synthetically investigated to identify and compare their quality parameters. After a detailed chemical analysis of water samples from three sources—wastewater, surface or canal water, and ground water—construction concrete material samples were prepared. The construction materials were developed with the same water–cement ratio, i.e., 0.60 for each concrete mix sample at two mix ratios—M1 (1:2:4) and M2 (1:1.5:3). Slump cone and compacting factor tests were conducted on the fresh concrete to determine its workability prior to its hardening. Then, at 7, 14, 21, and 28 days for each mix, tests for mechanical properties were carried out to determine the compressive, tensile, and flexure strengths. Results showed that the mechanical properties of the concrete made by utilizing wastewater and surface water were more noteworthy as compared to the concrete made by groundwater. This study will help in the production of concrete which depends on waste and surface canal water, even for large projects like rigid pavement construction and water-related structures. Full article

(This article belongs to the Special Issue Water Quality Modelling)

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16 pages, 5428 KiB

Open AccessArticle

Efficiency Enhancement of Chlorine Contact Tanks in Water Treatment Plants: A Full-Scale Application

by M. Anil Kizilaslan, Ender Demirel and Mustafa M. Aral

Processes 2019, 7(9), 551; https://doi.org/10.3390/pr7090551 - 21 Aug 2019

Cited by 13 | Viewed by 11479

Abstract

The mixing and disinfection performance of a full-scale chlorine contact tank (CCT) is thoroughly investigated by means of numerical simulations for seasonal water supply variations in the water treatment plant (WTP) of Eskisehir in Turkey. Velocity measurements and tracer studies are carried out [...] Read more.

The mixing and disinfection performance of a full-scale chlorine contact tank (CCT) is thoroughly investigated by means of numerical simulations for seasonal water supply variations in the water treatment plant (WTP) of Eskisehir in Turkey. Velocity measurements and tracer studies are carried out on a 1:10 scale laboratory model of the CCT to validate the numerical model. A good agreement between numerical and experimental results shows that the numerical model developed can be reliably used for the simulation of turbulent flow and solute transport in the full-scale CCT. Tracer studies indicate that the hydraulic performance of the CCT is classified as “average” according to the baffling factor, while the Morrill, Aral-Demirel (AD), and dispersion indexes indicate low mixing due to the recirculating and short-circuiting effects inside the chambers of the CCT. With respect to the first order modeling of chlorine decay and pathogen inactivation, chlorine concentrations are found to be significantly distinct for seasonal variations in water supply to maintain 3-log inactivation of Giardia cysts. A recently developed and patented slot-baffle design (SBD) is then applied to the full-scale CCT. It is found that the hydraulic efficiency of the CCT is improved to “high” and the Morrill index approaches 2, which identifies the system as a perfect mixing tank. Using the SBD, the chlorine demand has been successfully decreased by 19% while providing equivalent inactivation level. The novel SBD design also reduces energy loses in the turbulent flow through the tank and increases the energy efficiency of the CCT by 62%, which is significant for energy considerations in modern cities. Full article

(This article belongs to the Special Issue Water Quality Modelling)

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12 pages, 1735 KiB

Open AccessArticle

High Pressure Injection of Chemicals in a Gravel Beach

by Xiaolong Geng, Ali Abdollahi-Nasab, Chunjiang An, Zhi Chen, Kenneth Lee and Michel C. Boufadel

Processes 2019, 7(8), 525; https://doi.org/10.3390/pr7080525 - 08 Aug 2019

Cited by 2 | Viewed by 2531

Abstract

The remediation of beaches contaminated with oil includes the application of surfactants and/or the application of amendments to enhance oil biodegradation (i.e., bioremediation). This study focused on evaluating the practicability of the high pressure injection (HPI) of dissolved chemicals into the subsurface of [...] Read more.

The remediation of beaches contaminated with oil includes the application of surfactants and/or the application of amendments to enhance oil biodegradation (i.e., bioremediation). This study focused on evaluating the practicability of the high pressure injection (HPI) of dissolved chemicals into the subsurface of a lentic Alaskan beach subjected to a 5 m tidal range. A conservative tracer, lithium, in a lithium bromide (LiBr) solution, was injected into the beach at 1.0 m depth near the mid-tide line. The flow rate was varied between 1.0 and 1.5 L/min, and the resulting injection pressure varied between 3 m and 6 m of water. The concentration of the injected tracer was measured from four surrounding monitoring wells at multiple depths. The HPI associated with a flow rate of 1.5 L/min resulted in a Darcy flux in the cross-shore direction at 1.15 × 10⁻⁵ m/s compared to that of 7.5 × 10⁻⁶ m/s under normal conditions. The HPI, thus, enhanced the hydraulic conveyance of the beach. The results revealed that the tracer plume dispersed an area of ~12 m² within 24 h. These results suggest that deep injection of solutions into a gravel beach is a viable approach for remediating beaches. Full article

(This article belongs to the Special Issue Water Quality Modelling)

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15 pages, 4362 KiB

Open AccessArticle

Applying a Watershed and Reservoir Model in an Off-Site Reservoir to Establish an Effective Watershed Management Plan

by Chi-Feng Chen, Yi-Ru Wu and Jen-Yang Lin

Processes 2019, 7(8), 484; https://doi.org/10.3390/pr7080484 - 01 Aug 2019

Cited by 2 | Viewed by 2595

Abstract

Off-site reservoirs use water from other watersheds to supplement their water quantity. Water quality is usually better in off-site reservoirs than in onsite reservoirs, because in comparison to onsite reservoirs, watershed areas are smaller and fewer pollutants are collected; moreover, cleaner water is [...] Read more.

Off-site reservoirs use water from other watersheds to supplement their water quantity. Water quality is usually better in off-site reservoirs than in onsite reservoirs, because in comparison to onsite reservoirs, watershed areas are smaller and fewer pollutants are collected; moreover, cleaner water is introduced. However, in Taiwan, the water quality of some off-site reservoirs can gradually worsen, and this factor needs to be addressed. In this study, the Liyutan reservoir in central Taiwan was used as an example to demonstrate the process of evaluating pollution in an off-site reservoir. Pollution loads from point sources (PSs) and nonpoint sources (NPSs) were carefully estimated. Domestic sewage and tourist wastewater were considered the major PS loads in this study. The NPS load evaluation was dependent on the results of a verified watershed model, the stormwater management model (SWMM). The observed data in 2015 and 2016 and supplementary total phosphorous (TP) samplings in upstream rivers in 2018 were used to validate the model results. Model calibration and verification were implemented during dry weather and wet weather to ensure the accuracy of the PS and NPS simulations. The results of this study showed that the average total phosphorous (TP) load generated from within the watershed was 9013 kg/y, and that the TP load from outside the watershed was 4545 kg/y. The percentages of TP loads from NPSs and PSs in the watershed were 83% and 17%, respectively. Finally, we used a verified Vollenweider model to convert the TP loads to the TP concentration in the reservoir. The pollution reduction measures and the associated predicted water quality values were assessed using the verified models. Full article

(This article belongs to the Special Issue Water Quality Modelling)

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15 pages, 5402 KiB

Open AccessArticle

Verifying the Representativeness of Water-Quality Monitoring to Manage Water Levels in the Wicheon River, South Korea

by Jung Min Ahn and Yong-Seok Kim

Processes 2019, 7(5), 295; https://doi.org/10.3390/pr7050295 - 17 May 2019

Cited by 1 | Viewed by 3061

Abstract

Changes in water level between the mainstems and tributaries of a river can create backflow effects that alter the representativeness of water-quality monitoring data. In South Korea, 16 multi-functional weirs intended to manage water levels were constructed on 4 major rivers as part [...] Read more.

Changes in water level between the mainstems and tributaries of a river can create backflow effects that alter the representativeness of water-quality monitoring data. In South Korea, 16 multi-functional weirs intended to manage water levels were constructed on 4 major rivers as part of a restoration project. However, they are causing backwater effects in tributaries that coincide with poorer water-quality measurements at monitoring stations along these tributaries despite there being no change in upstream pollution sources. Therefore, this study developed a new methodology for verifying the representativeness of a water-quality monitoring network via spatiotemporal observations of electrical conductivity, self-organizing maps for monthly pattern analysis, locally weighted scatter plot smoothing for trend analysis, load duration curves, and numerical modeling. This approach was tested on the Wicheon River, a primary tributary of the Nakdong River, because the measured decline in water quality there has the potential to trigger major policy changes in the basin including limits on local development. The results clearly show that the monitoring station in the lower Wicheon is negatively affected by weir-derived backwater from the Nakdong, suggesting that this station needs to be moved upstream or a new station established upstream, beyond the backwater effects. Our approach was able to assess clearly the representativeness of an existing water-quality monitoring network using widely accessible data and methods, making this type of assessment applicable to many other situations around the world. Full article

(This article belongs to the Special Issue Water Quality Modelling)

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22 pages, 6778 KiB

Open AccessFeature PaperArticle

Computational Evaluation of Mixing Performance in 3-D Swirl-Generating Passive Micromixers

by Mahmut Burak Okuducu and Mustafa M. Aral

Processes 2019, 7(3), 121; https://doi.org/10.3390/pr7030121 - 27 Feb 2019

Cited by 8 | Viewed by 3352

Abstract

Computational Fluid Dynamics (CFD) tools are used to investigate fluid flow and scalar mixing in micromixers where low molecular diffusivities yield advection dominant transport. In these applications, achieving a numerical solution is challenging. Numerical procedures used to overcome these difficulties may cause misevaluation [...] Read more.

Computational Fluid Dynamics (CFD) tools are used to investigate fluid flow and scalar mixing in micromixers where low molecular diffusivities yield advection dominant transport. In these applications, achieving a numerical solution is challenging. Numerical procedures used to overcome these difficulties may cause misevaluation of the mixing process. Evaluation of the mixing performance of these devices without appropriate analysis of the contribution of numerical diffusion yields over estimation of mixing performance. In this study, two- and four-inlet swirl-generating micromixers are examined for different mesh density, flow and molecular diffusivity scenarios. It is shown that mesh densities need to be high enough to reveal numerical diffusion errors in scalar transport simulations. Two-inlet micromixer design was found to produce higher numerical diffusion. In both micromixer configurations, when cell Peclet numbers were around 50 and 100 for Reynolds numbers 240 and 120, the numerical diffusion effects were tolerable. However, when large cell Peclet number scenarios were tested, it was found that the molecular diffusivity of the fluid is completely masked by false diffusion errors. Full article

(This article belongs to the Special Issue Water Quality Modelling)

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14 pages, 2065 KiB

Open AccessArticle

Dynamics of Water Quality: Impact Assessment Process for Water Resource Management

by Ejaz-ul-Hassan Bhatti, Mudasser Muneer Khan, Syyed Adnan Raheel Shah, Syed Safdar Raza, Muhammad Shoaib and Muhammad Adnan

Processes 2019, 7(2), 102; https://doi.org/10.3390/pr7020102 - 15 Feb 2019

Cited by 11 | Viewed by 5727

Abstract

Surface water is an important source of water supply for irrigation purpose and in urban areas, sewage water is being disposed of in nearby canals without treatment. A study was conducted to investigate the dynamics of water quality of irrigation canal as a [...] Read more.

Surface water is an important source of water supply for irrigation purpose and in urban areas, sewage water is being disposed of in nearby canals without treatment. A study was conducted to investigate the dynamics of water quality of irrigation canal as a result of this practice. The study ascertained the impact of different salinity parameters, indices and approaches to examine the hazardous effects on quality of canal water. The study analyses the samples collected for various parameters like pH, TDS, EC, Na, Cl, Ca, Mg, K, CO₃, HCO₃ etc. It helped to decide the restriction on use of water based on FAO-UN guidelines. Investigations were focused on assessment of contaminants affecting the quality of water and having hazardous effects on different stages of irrigation water usage. Wilcox diagram and Doneen’s approach-based analysis helped to identify the class and quality of water. This study shall help to analyze the quality of water and provide support to the decision makers for better water resource management and policy development for irrigation purpose i.e., treatment and distribution of water resource. Full article

(This article belongs to the Special Issue Water Quality Modelling)

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2 pages, 975 KiB

Open AccessCorrection

Correction: Koşucu, M.M., et al. Hydrodynamic and Hydrographic Modeling of Istanbul Strait. Processes 2019, 7, 710

by Mehmet Melih Koşucu, Mehmet Cüneyd Demirel, V.S. Ozgur Kirca and Mehmet Özger

Processes 2020, 8(2), 205; https://doi.org/10.3390/pr8020205 - 06 Feb 2020

Viewed by 1581

Abstract

We were not aware of an error made in the proofreading phase; therefore, we wish to make the following correction to Figure 1b from this paper [...] Full article

(This article belongs to the Special Issue Water Quality Modelling)

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