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result(s) for
"Water Purification Simulation methods."
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Numerical simulation and experimental verification of venturi tube hydraulic cavitation
This study conducted a numerical simulation of hydraulic cavitation characteristics in a Venturi tube using FLUENT software. The Realizable k-ε turbulence model, Mixture multiphase flow model, and Singhal cavitation model were employed to investigate the effects of inlet pressure, outlet cone angle, and throat parameters (diameter and length) on cavitation performance. A critical inlet pressure threshold (~1.5 MPa) exists, beyond which the cavitation growth rate significantly decreases. Increasing the outlet cone angle weakens cavitation intensity due to reduced pressure recovery efficiency. Larger throat diameters enhance cavitation generation, whereas extended throat lengths suppress it by prolonging pressure recovery. Experimental validation demonstrated consistent trends between temperature variations, conductivity measurements, and simulation results, confirming the validity of the numerical methodology. These findings provide theoretical guidance for optimizing Venturi tube structures in industrial applications such as wastewater treatment and chemical reactors. The systematic analysis of parameter interactions offers practical insights for cavitation control and device performance enhancement.
Journal Article
Evaluation of the effluent quality parameters of wastewater treatment plant based on uncertainty analysis and post-processing approaches (case study)
Wastewater treatment plants (WWTPs) are highly complicated and dynamic systems and so their appropriate operation, control, and accurate simulation are essential. The simulation of WWTPs according to the process complexity has become an important issue in growing environmental awareness. In recent decades, artificial intelligence approaches have been used as effective tools in order to investigate environmental engineering issues. In this study, the effluent quality of Tabriz WWTP was assessed using two intelligence models, namely support Vector Machine (SVM) and artificial neural network (ANN). In this regard, several models were developed based on influent variables and tested via SVM and ANN methods. Three time scales, daily, weekly, and monthly, were investigated in the modeling process. On the other hand, since applied methods were sensitive to input variables, the Monte Carlo uncertainty analysis method was used to investigate the best-applied model dependability. It was found that both models had an acceptable degree of uncertainty in modeling the effluent quality of Tabriz WWTP. Next, ensemble approaches were applied to improve the prediction performance of Tabriz WWTP. The obtained results comparison showed that the ensemble methods represented better efficiency than single approaches in predicting the performance of Tabriz WWTP.
Journal Article
Environmental DNA metabarcoding for fish community analysis in backwater lakes: A comparison of capture methods
The use of environmental DNA (eDNA) methods for community analysis has recently been developed. High-throughput parallel DNA sequencing (HTS), called eDNA metabarcoding, has been increasingly used in eDNA studies to examine multiple species. However, eDNA metabarcoding methodology requires validation based on traditional methods in all natural ecosystems before a reliable method can be established. To date, relatively few studies have performed eDNA metabarcoding of fishes in aquatic environments where fish communities were intensively surveyed using multiple traditional methods. Here, we have compared fish communities' data from eDNA metabarcoding with seven conventional multiple capture methods in 31 backwater lakes in Hokkaido, Japan. We found that capture and field surveys of fishes were often interrupted by macrophytes and muddy sediments in the 31 lakes. We sampled 1 L of the surface water and analyzed eDNA using HTS. We also surveyed the fish communities using seven different capture methods, including various types of nets and electrofishing. At some sites, we could not detect any eDNA, presumably because of the polymerase chain reaction (PCR) inhibition. We also detected the marine fish species as sewage-derived eDNA. Comparisons of eDNA metabarcoding and capture methods showed that the detected fish communities were similar between the two methods, with an overlap of 70%. Thus, our study suggests that to detect fish communities in backwater lakes, the performance of eDNA metabarcoding with the use of 1 L surface water sampling is similar to that of capturing methods. Therefore, eDNA metabarcoding can be used for fish community analysis but environmental factors that can cause PCR inhibition, should be considered in eDNA applications.
Journal Article
A response surface methodology for optimization of 2,4-dichlorophenoxyacetic acid removal from synthetic and drainage water: a comparative study
The potential of a granular activated carbon (GAC), a rice husk biochar (BRH), and multi-walled carbon nanotubes (MWCNTs) for removing 2,4-dichlorophenoxyacetic acid (2,4-D) from simulated wastewater and drainage water has been evaluated. In this regard, a response surface methodology (RSM) with a central composite design (CCD) (CCD-RSM design) was used to optimize the removal of 2,4-D from simulated wastewater under different operational parameters. The maximum adsorption capacities followed the order GAC > BRH > MWCNTs, whereas the equilibrium time increased in the order MWCNTs < GAC < BRH. In the case of GAC and BRH, the 2,4-D removal percentage increased significantly upon increasing the adsorbent dosage and temperature and decreased upon increasing the initial 2,4-D concentration and pH. The results showed that the contact time and temperature were not important as regards the adsorption efficiency of 2,4-D by MWCNTs, whereas rapid removal of 2,4-D from simulated wastewater was achieved within the first 5 min of contact with the MWCNTs. The results confirmed that the Freundlich isotherm model with the highest coefficient of determination (
R
2
) and the lowest standard error of the estimate (SEE) satisfactorily fitted the 2,4-D experimental data. In addition, successful usage of the three adsorbents investigated was observed for removal of 2,4-D from drainage water from an agricultural drainage system. An economic analysis with a rate of return (ROR) method indicated that BRH could be used as an eco-friendly, low-cost, versatile, and high adsorption capacity alternative to GAC and MWCNTs for the removal of 2,4-D.
Journal Article
Modeling, simulation, and optimization behavior of pharmaceutical compound removal from water in SR-AOPs technique for wastewater treatment
Tetracycline hydrochloride (TC) is an antibiotic frequently detected in water sources globally. Developing effective strategies for the removal of this pharmaceutical contaminant from water and wastewater is crucial. The primary objective of this study is to develop computational models to accurately predict and optimize the TC removal process. Response Surface Methodology (RSM) was used to model the relationship between the removal efficiency (RE) and three key variables: initial TC concentration (TC
0
), catalyst dosage, and peroxymonosulfate (PMS) dose over treatment time. Finally, Response surface methodology optimization was used to discover the best approach for removing Tetracycline hydrochloride. The findings demonstrated the great accuracy of response surface methodology and artificial neural networks in predicting the RE behavior of TC in an aqueous solution. The artificial neural network’s output MSE, MAE, and R
2
accuracy metrics are 2.02E−02, 7.38E−03, and 9.99E−01, respectively. To solve the worldwide problem of water pollution, the findings of this work might be used to create optimal states and strategies for removing and degrading pharmaceutical contaminants in water using computational artificial intelligence.
Journal Article
Phosphate and ammonium adsorption of the modified biochar based on Phragmites australis after phytoremediation
To effectively remove N and P from eutrophic water, the
Phragmites australis
after phytoremediation was harvested for preparation of modified biochar. The MgCl
2
-modified biochar (MPB) was successfully synthesized at 600 °C under N
2
circumstance. The physiochemical characteristics, the adsorption capacity for N and P in the simulated solution, and their adsorption mechanism of MPB were then determined, followed by the treatment of eutrophic water of Tai lake and its inflow river from agricultural source. The results demonstrated that the MPB presented high adsorption capacity to both simulated NH
4
-N and PO
4
-P with the maximum adsorption capacity exceeding 30 and 100 mg g
−1
, respectively. The entire ammonium adsorption process could be described by a pseudo-second-order kinetic model whereas the phosphate adsorption process could be divided into three phases, as described by both intra-particle diffusion model and the pseudo-first-order kinetic. It was further found that the dominant mechanism for ammonium adsorption was Mg
2+
exchange instead of functional groups and surface areas and the Mg-P precipitation was the main mechanism for phosphate adsorption. The MPB also showed high removal ratio of practical TP which reached nearly 90% for both the water in Tai lake and its agricultural source. It suggested that MPB based on harvested
P. australis
was a promising composite for eutrophic water treatment and it could deliver multiple benefits.
Graphic abstract
Journal Article
CFD for wastewater treatment: an overview
Computational fluid dynamics (CFD) is a rapidly emerging field in wastewater treatment (WWT), with application to almost all unit processes. This paper provides an overview of CFD applied to a wide range of unit processes in water and WWT from hydraulic elements like flow splitting to physical, chemical and biological processes like suspended growth nutrient removal and anaerobic digestion. The paper's focus is on articulating the state of practice and research and development needs. The level of CFD's capability varies between different process units, with a high frequency of application in the areas of final sedimentation, activated sludge basin modelling and disinfection, and greater needs in primary sedimentation and anaerobic digestion. While approaches are comprehensive, generally capable of incorporating non-Newtonian fluids, multiphase systems and biokinetics, they are not broad, and further work should be done to address the diversity of process designs. Many units have not been addressed to date. Further needs are identified throughout, but common requirements include improved particle aggregation and breakup (flocculation), and improved coupling of biology and hydraulics.
Journal Article
Benchmark simulation model no 2: general protocol and exploratory case studies
Over a decade ago, the concept of objectively evaluating the performance of control strategies by simulating them using a standard model implementation was introduced for activated sludge wastewater treatment plants. The resulting Benchmark Simulation Model No 1 (BSM1) has been the basis for a significant new development that is reported on here: Rather than only evaluating control strategies at the level of the activated sludge unit (bioreactors and secondary clarifier) the new BSM2 now allows the evaluation of control strategies at the level of the whole plant, including primary clarifier and sludge treatment with anaerobic sludge digestion. In this contribution, the decisions that have been made over the past three years regarding the models used within the BSM2 are presented and argued, with particular emphasis on the ADM1 description of the digester, the interfaces between activated sludge and digester models, the included temperature dependencies and the reject water storage. BSM2-implementations are now available in a wide range of simulation platforms and a ring test has verified their proper implementation, consistent with the BSM2 definition. This guarantees that users can focus on the control strategy evaluation rather than on modelling issues. Finally, for illustration, twelve simple operational strategies have been implemented in BSM2 and their performance evaluated. Results show that it is an interesting control engineering challenge to further improve the performance of the BSM2 plant (which is the whole idea behind benchmarking) and that integrated control (i.e. acting at different places in the whole plant) is certainly worthwhile to achieve overall improvement.
Journal Article
Facile Synthesis of ZIF-67 for the Adsorption of Methyl Green from Wastewater: Integrating Molecular Models and Experimental Evidence to Comprehend the Removal Mechanism
Organic dyes with enduring colors which are malodorous are a significant source of environmental deterioration due to their virulent effects on aquatic life and lethal carcinogenic effects on living organisms. In this study, the adsorption of methyl green (MG), a cationic dye, was achieved by using ZIF-67, which has been deemed an effective adsorbent for the removal of contaminants from wastewater. The characterization of ZIF-67 was done by FTIR, XRD, and SEM analysis. The adsorption mechanism and characteristics were investigated with the help of control batch experiments and theoretical studies. The systematical kinetic studies and isotherms were sanctioned with a pseudo-second-order model and a Langmuir model (R2 = 0.9951), confirming the chemisorption and monolayer interaction process, respectively. The maximum removal capacities of ZIF-67 for MG was 96% at pH = 11 and T = 25 °C. DFT calculations were done to predict the active sites in MG by molecular electrostatic potential (MEP). Furthermore, both Molecular dynamics and Monte Carlo simulations were also used to study the adsorption mechanism.
Journal Article