Review of experimental procedures and modelling techniques for flow behaviour and their relation to residence time in constructed wetlands

Stephenson, Ruth; Sheridan, Craig

doi:10.1016/j.jwpe.2021.102044

Cited by 17 publications

(6 citation statements)

References 71 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The procedure was extensively described by Octave Levenspiel [44]. However, there are still issues related to the type of the tracer, how it is inserted into the flow, the vessel boundaries, and how its signal is detected and eventually converted to finally plot the concentration vs. time curve (the C-curve) [7,[45][46][47][48]. In brief, the tracer methodology is an experimental procedure that introduces a known amount of tracer into a system and measures its concentration over time at different points (most commonly at the exit).…”

Section: Tracer Methodology Fundamentalsmentioning

confidence: 99%

“…Moreover, the tracer must be detectable at very low concentrations, and the measurement technique must be sensitive and accurate. Since the tracer method is applied in various domains [11], including chemical engineering [3], environmental engineering [46], metallurgy [49], hydrology [48], pharmaceutics [5,50], medicine [51], and many others, there is a large variety of tracers such as electrolytes, dyes, stable or radioactive isotopes, [52] and others [3]. Conductivity, fluorescence, color, X-ray emission, or even temperature are among the properties that allow tracer detection, and most of the time, calibration curves are used to convert a specific property into tracer concentration.…”

Section: Tracer Selectionmentioning

confidence: 99%

See 1 more Smart Citation

Residence Time Distribution: Literature Survey, Functions, Mathematical Modeling, and Case Study—Diagnosis for a Photochemical Reactor

Nechita,

Suditu,

Puițel

et al. 2023

Processes

View full text Add to dashboard Cite

This paper aims to provide an overview of the fundamentals, development, and evolution of residence time distribution (RTD) methodology and its applications to the flow and mixing of fluids (and solid particles) modeling in different systems. A concise literature analysis is followed by a succinct presentation of RTD methodology’s experimental and theoretical foundations and RTD-based mathematical modeling, highlighting its importance. An experimental demonstration of RTD diagnostics on a photochemical reactor is performed to identify the most practical locations for the inlet/outlet pipes (axial or radial) and the photochemical reactor’s ideal working posture (horizontal, vertical, or inclined) and to understand the level of mixing and to determine the fluid flow defects. Using the relevant RTD functions and the corresponding central moments, it was possible to show that short circuits and dead zones occurred in each of the six considered reactor configurations. Following these investigations, design solutions were proposed to achieve a convenient exposure time, proper mixing, and uniform irradiation inside the reactor.

show abstract

Section: Tracer Methodology Fundamentalsmentioning

confidence: 99%

Section: Tracer Selectionmentioning

confidence: 99%

Residence Time Distribution: Literature Survey, Functions, Mathematical Modeling, and Case Study—Diagnosis for a Photochemical Reactor

Nechita,

Suditu,

Puițel

et al. 2023

Processes

View full text Add to dashboard Cite

show abstract

“…Black-box models use statistical approaches or simple rate-based equations to predict pollutant removal, without accounting for the speci c removal process involved, Table (3). Process-based models, on the other hand, try to explicitly model these various removal processes, and often also include more physically realistic modeling of wetland hydrology and hydraulics (Stephenson and Sheridan, 2021). Several studies have examined modeling of CWs (Meyer et al, 2015;Galanopoulos et al, 2013;Kumar and Zhao, 2011; Stephenson and Sheridan, 2021), but typically with a focus on a particular type of wetland or speci c process.…”

Section: Fws Modelling Approachesmentioning

confidence: 99%

Free water surface constructed wetlands: Review of pollutant removal performance and modeling approaches

Gaballah,

Yousefyani,

Karami

et al. 2024

Preprint

View full text Add to dashboard Cite

Free water surface constructed wetlands (FWSCWs) for the treatment of various wastewater types have evolved significantly over the last few decades. With an increasing need and interest in FWSCWs applications worldwide due to their cost-effectiveness and other benefits, this paper reviews recent literature on FWSCWs' ability to remove different types of pollutants (i.e., nutrients, heavy metals, antibiotics, and pesticides) that may co-exist in wetland inflow, and discusses approaches for simulating hydraulic and pollutant removal processes. A bibliometric analysis of recent literature reveals that China has the highest number of publications, followed by the USA. The collected data show that FWSCWs can remove an average of 61.6%, 67.8%, 54.7%, and 72.85% of inflowing nutrients, heavy metals, antibiotics, and pesticides, respectively. Optimizing each pollutant removal process requires specific design parameters. Removing heavy metal requires the lowest hydraulic retention time (HRT) (average of 4.78 days), removing pesticides requires the lowest water depth (average of 0.34 meters), and nutrient removal requires the largest system size. Vegetation, especially Typha spp. and Phragmites spp., play an important role in FWSCWs' system performance, making significant contributions to the removal process. Various modeling approaches (i.e., black-box and process-based) were comprehensively reviewed, revealing the need for including the internal process mechanisms related to the biological processes along with plants spp., that supported by a further research with field study validations. This work presents a state-of-the-art, systematic, and comparative discussion on the efficiency of FWSCWs in removing different pollutants, main design factors, the vegetation, and well-described models for performance prediction.

show abstract

“…Another factor that can also be observed is the possible tracer losses across the CWS since it is known that NaCl can be absorbed by plants, in the form of Na + and Cl − , or adsorbed in the substrate system [34]. Similarly, rhodamine WT can be adsorbed to the substrate of the systems or oxidized by photolysis [26,38].…”

Section: Hydrodynamic Studymentioning

confidence: 99%

“…The removal of pollutants in CWS depends on the time the wastewater remains in the system, and this time is influenced by the hydraulic behavior. This behavior is well understood by the use of tracers [26]. Studies with response stimulus (use of tracers) have been used to understand the hydrodynamic behavior of CWS, and these researches enable the understanding of the dispersion of pollutants in the system, aiding the fitting of first-order kinetic models [26,27].…”

Section: Introductionmentioning

confidence: 99%

Swine Wastewater Treatment in Constructed Wetland Systems: Hydraulic and Kinetic Modeling

Ramos

Borges

Coimbra

et al. 2022

Water

View full text Add to dashboard Cite

The use of constructed wetland systems (CWS) is presented as an alternative for the treatment of effluents since these have reduced implementation costs and relative ease of operation. The present research was undertaken to evaluate to study the hydrodynamic and the fitting of first-order mathematical kinetic models for the removal of pollutants in CWS. Three CWS were built, using expanded clay as filter support: one cultivated with Polygonum punctatum (CWSw), another cultivated with Chrysopogon zizanioides (CWSV), and a control unit (CWSc). The actual retention time was 3.12 days in the CWSc, whereas, in the CWSw and CWSv, we observed values of 4.14 and 4.11 days, respectively. The dispersion values were high in all CWS. The values of chemical oxygen demand (COD) across the length of the CWS were used to fit the kinetic models that describe the first-order decay of organic matter over the CWS. The models that showed a better fit to the experimental data were the plug-flow with residual concentration, the continuous stirred tank reactor, and Shepherd’s models.

show abstract

Review of experimental procedures and modelling techniques for flow behaviour and their relation to residence time in constructed wetlands

Cited by 17 publications

References 71 publications

Residence Time Distribution: Literature Survey, Functions, Mathematical Modeling, and Case Study—Diagnosis for a Photochemical Reactor

Residence Time Distribution: Literature Survey, Functions, Mathematical Modeling, and Case Study—Diagnosis for a Photochemical Reactor

Free water surface constructed wetlands: Review of pollutant removal performance and modeling approaches

Swine Wastewater Treatment in Constructed Wetland Systems: Hydraulic and Kinetic Modeling

Contact Info

Product

Resources

About