Research Paper
Saeid Jeddi; Jalal Sadeghian
Abstract
Hydraulic structures have a long history, with weirs being among the earliest developed; a notable example of these is the side weir. Side weirs are of different shapes, including a nonlinear weir installed on the dam crest. Weirs with nonlinear designs come in various forms, like labyrinth and piano ...
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Hydraulic structures have a long history, with weirs being among the earliest developed; a notable example of these is the side weir. Side weirs are of different shapes, including a nonlinear weir installed on the dam crest. Weirs with nonlinear designs come in various forms, like labyrinth and piano key weirs; these are used when weir length is restricted, to maximize crest length, which subsequently increases discharge capacity. This study examines and contrasts how piano key and labyrinth weirs function as side weirs, since there has been little research on piano key side weirs. Within this study, the experimental models incorporated trapezoidal, rectangular, and triangular Labyrinth weirs, alongside piano key weirs, each characterized by four distinct heights 5, 10, 15, and 20 cm and three cycles, where the piano key weirs were classified as A-type. At a certain Ht/P ratio, weirs with a smaller height had the maximum discharge coefficient and vice versa for weirs with a larger height. When a straight piano key weir and a rectangular labyrinth weir are both placed at a right angle to the stream, the piano key weir performs better. Conversely, the present study, which evaluated the aforementioned weirs as side weirs, yielded contrasting results; the rectangular labyrinth weir exhibited superior efficiency to the piano key weir. The study’s findings revealed triangular labyrinth side weirs exhibited a superior discharge coefficient (maximum 0.689), while rectangular labyrinth weirs outperformed piano key weirs by up to 24.85 % in side-channel arrangements.
Research Paper
Rozita Moradi; Majid Mohadesi
Abstract
The aim of this research was to separate mercury from gold refining wastewater using activated carbon (AC) from natural shells. To this end, walnut and coconut shells were used as the main source of AC. The characterizations of both ACs were compared by FTIR, BET, and SEM analyses. The FTIR results revealed ...
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The aim of this research was to separate mercury from gold refining wastewater using activated carbon (AC) from natural shells. To this end, walnut and coconut shells were used as the main source of AC. The characterizations of both ACs were compared by FTIR, BET, and SEM analyses. The FTIR results revealed interactions between the solute and the functional groups on the adsorbent surface. According to the BET results, the mean pore diameter (MPD) of AC from coconut shells (CSAC) was smaller than that derived from walnut shells (WSAC). The specific surface areas for CSAC and WSAC were 1069.1 and 119.6 m2/g, respectively. SEM results revealed that the porous texture of ACs emanates from their cellular structure. This research further studied the impact of operational parameters “adsorbent dose” (0.3-3.8 g/L), “pH” (2-9), and “residence time” (10-120 min) on mercury removal. Under optimal operational conditions, the mercury removal rate reached 97% (for WSAC) and 93% (for CSAC). Kinetic model assessments revealed the highest agreement between the experimental data and the pseudo-first-order (PFO) model. Both adsorbents were regenerable, with their performance (compared to fresh adsorbents) exceeding 90% after each regeneration.
Research Paper
Mukhtar Dhajir Shubber; Mohammed Kadhum Al kasser; Daryoush Yousefi Kebria
Abstract
The study aims to show the role of pH value and the feasible mechanisms that affect the adsorption capacity by the theoretical concept and experimental work. The protonation, ionization, hydrophobicity, dissociation, precipitation, hydrolysis, hydroxylation, electrical repulsion or interaction, ion exchange, ...
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The study aims to show the role of pH value and the feasible mechanisms that affect the adsorption capacity by the theoretical concept and experimental work. The protonation, ionization, hydrophobicity, dissociation, precipitation, hydrolysis, hydroxylation, electrical repulsion or interaction, ion exchange, and complexation and chelating are effective mechanisms that have been studied theoretically to show their essential role in the absorption process and how they are affected by the pH value. Moreover, using varied pH values (2, 4, 6.5, 9, 11, and 13) to verify experimentally the role of the studied mechanisms on the adsorption capacity utilizing the recycled bentonite waste as adsorbent to adsorb the heavy metals, methylene blue dye, and engine oil as adsorbates from aqueous solution. It was apparent that the pH solution has an influential role in the adsorption capacity and from the difficulty in predicting the effect without making the experimental investigations due to the nature of the adsorbent and adsorbate that affected the ten mechanisms where the pH of the high adsorption capacity for heavy metal was alkaline (>11) and for the methylene blue and engine oil was neutral(≈ 6.5).
Research Paper
Mahdi Ghaderi; Ali Attarzadeh
Abstract
Oily pollutants, such as 4-nitrophenol, are unavoidable problems. One of the methods employed for treating wastewater polluted with 4-nitrophenol is the use of moving bed biofilm reactors (MBBRs). The present research compared, for the first time, the two common types of media (Kaldness K1 and Bee Cell ...
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Oily pollutants, such as 4-nitrophenol, are unavoidable problems. One of the methods employed for treating wastewater polluted with 4-nitrophenol is the use of moving bed biofilm reactors (MBBRs). The present research compared, for the first time, the two common types of media (Kaldness K1 and Bee Cell 2000) in MBBR for treating wastewater polluted with 4-nitrophenol, and determined and reported the optimum conditions for media types and heat. A biofilm layer was first formed on the surface of the media in each reactor, and then the microorganisms were acclimatized to the contaminants. Following that, changes in efficiency with variations in initial COD concentration (400-2,500 mg/l), retention time (8, 12, 24, and 48 h), and filling ratio (30, 50, and 70 %) in the two reactors were determined and compared. The highest efficiencies (84 and 80 percent for the reactor with Bee Cell 2000 media and that with Kaldness K1 media, respectively) were observed. Both reactors containing Bee Cell 2000 media and Kaldness K1 media were very capable of treating wastewater polluted with 4-nitrophenol at 20 °C. Still, the reactor that included the Bee Cell 2000 media yielded better results compared to that containing the Kaldness K1 media.
Research Paper
Seyed Mehdi Sajjadi; Ghader Hosseinzadeh
Abstract
In this study, 5 wt. %Cu-doped TiO₂ nanoparticles (NPs) were synthesized through a green and sustainable method, utilizing Cannabis sativa leaf extract as a reducing agent to promote eco-friendly wastewater treatment. The NPs were characterized using XRD, FESEM, BET, EDAX, and TEM, revealing uniform ...
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In this study, 5 wt. %Cu-doped TiO₂ nanoparticles (NPs) were synthesized through a green and sustainable method, utilizing Cannabis sativa leaf extract as a reducing agent to promote eco-friendly wastewater treatment. The NPs were characterized using XRD, FESEM, BET, EDAX, and TEM, revealing uniform dispersion, an average particle size of approximately 20.5 nm, and a high surface area of 92 m²/g. These NPs were employed for adsorption of Methylene Blue (MB) and Rhodamine B (RhB) dyes from aqueous solutions at initial concentrations of 1–10 mg/L. Adsorption experiments, conducted over 150 min, showed equilibrium data best fitting the Freundlich isotherm (R² = 0.9979 for MB, 0.9995 for RhB), indicating multilayer adsorption. Kinetic studies confirmed that the Elovich models provided the best fit (R² > 0.997), suggesting chemisorption-dominated processes. The NPs exhibited high adsorption efficiency, offering a cost-effective and sustainable solution for treating textile wastewater, addressing critical environmental challenges posed by industrial dyes.
Research Paper
Ali Nasirian; Mahsa Mardani
Abstract
Hydro-climatic research and water resource management in arid, data-scarce regions depend fundamentally on precise precipitation data. This study presents the first comprehensive, multi-scale evaluation of four prominent gridded precipitation products (GPPs)—TRMM, CHIRPS, GSMaP, and ERA5—in ...
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Hydro-climatic research and water resource management in arid, data-scarce regions depend fundamentally on precise precipitation data. This study presents the first comprehensive, multi-scale evaluation of four prominent gridded precipitation products (GPPs)—TRMM, CHIRPS, GSMaP, and ERA5—in the climatically challenging and sparsely gauged South Khorasan province of Iran (2010–2019). Using ground-based observations as a reference, GPP performance was evaluated across multiple timescales with a suite of statistical metrics. The evaluation framework leverages diagnostic visualizations, such as Taylor and performance diagrams, to provide deeper insights into error structures than can be achieved through traditional map-based assessments. The analysis revealed a clear performance ranking: the satellite-based TRMM and GSMaP consistently performed best, showing higher accuracy (median RMSE ≈ 2.91–3.05 mm/day), stronger correlation (median CC ≈ 0.63–0.65), and a more balanced detection skill (median CSI ≈ 0.43–0.45). In contrast, the ERA5 reanalysis product, despite achieving the highest probability of detection (POD ≈ 0.78), suffered from notable systematic biases and the largest random errors. Performance for all products degraded during the arid summer, and estimation errors systematically increased in wetter regions. We conclude that the gauge-adjusted satellite products, GSMaP and TRMM, provide the most dependable precipitation estimates for the study area. These findings offer a critical, evidence-based guide for selecting appropriate GPPs in this vulnerable environment and provide insights for future algorithm development.
Research Paper
Aghdas Afsharirad; Amir Hossein Sayyahzadeh; Shahriar Mahdavi
Abstract
Phosphorus is one of the main limiting factors for eutrophication in water resources. According to the increasing population and the worsening of the healthy water shortage crisis in recent years, it is necessary to control the concentration of this element (phosphorus) in water resources. This study ...
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Phosphorus is one of the main limiting factors for eutrophication in water resources. According to the increasing population and the worsening of the healthy water shortage crisis in recent years, it is necessary to control the concentration of this element (phosphorus) in water resources. This study was performed with the aim of phosphorus removal efficiency (PRE) and sludge volumetric index (SVI) modeling in the chemical precipitation process, and by using poly-aluminum chloride as a precipitator. In this study, the response surface method (RSM) was used based on the central composite design (CCD) to model the effects of pH, the precipitator concentration, mixing time, mixing speed, settling time, and phosphorus initial concentration on the two desired answers including PRE and SVI. Analysis of variances (ANOVA) of the responses showed that among the above factors, precipitator concentration, phosphorus initial concentration, and settling time on phosphorus removal efficiency has been significant. Also, the most important parameters affecting the sludge volume index were precipitator concentration, settling time, and pH. Phosphorus removal efficiency and sludge volume index under optimal condition (pH=7.46, poly-aluminum chloride concentration=104.85 mg/L, mixing time=133 s, mixing speed=152 rpm, settling time=36 min and phosphorus initial concentration= 6.33 mg/L) was predicted to be 84.68% and 151.79 mL/g, respectively. Based on the average responses obtained from three times experiment under predicted optimized conditions, the phosphorus removal efficiency was 80.03%, the sludge volumetric index was 200.07 mL/g. The predicted and obtained data from the experiments showed conformity, which indicates the accuracy of modeling. The findings of this study showed that the factors of precipitator concentration, settling time, and pH should be well controlled to manage the chemical precipitation process using poly-aluminum chloride.
Review Paper
Kamran Mohammadi
Abstract
A wide range of applied fluid mechanics problems are related to transient flows. In conventional analyses, the relationship between wall shear stress and average cross-sectional velocity — valid for steady flow — is often assumed to hold under unsteady conditions. This simplification, typically ...
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A wide range of applied fluid mechanics problems are related to transient flows. In conventional analyses, the relationship between wall shear stress and average cross-sectional velocity — valid for steady flow — is often assumed to hold under unsteady conditions. This simplification, typically implemented through the Darcy–Weisbach or Hazen–Williams formulations, leads to an underestimation of frictional losses in rapid transients by up to 15–25% according to experimental studies. Unsteady friction formulations incorporate an additional term to account for acceleration effects, thereby improving prediction accuracy. For instance, Zielke’s convolution-based model achieves less than 2% error in laminar regimes, while simplified approaches such as Trikha’s approximation reduce computational demand by approximately 60% with only a minor accuracy loss (<5%) for low-Reynolds turbulent flows. Instantaneous acceleration-based (IAB) models, such as Brunone’s, can reduce pressure attenuation discrepancies by 10–18% compared to quasi-steady models, and two-coefficient IAB variants further improve waveform agreement by separating temporal and spatial acceleration contributions. This review critically examines the major classes of unsteady friction models outlining their theoretical basis, computational performance, and applicability domains. Furthermore, classification schemes, practical implementation aspects, challenges, and future research directions, including hybrid physics–machine learning approaches, are discussed in detail.
Research Paper
Mahdi Jamshidi; Ali Amoozadeh
Abstract
Nanostructured semiconductors have emerged as promising photocatalysts for sustainable wastewater purification. Among them, TiO₂–P25 (commercial TiO₂) is widely used; however, its wide band gap restricts visible light activity. A simple and eco friendly approach to overcome this limitation ...
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Nanostructured semiconductors have emerged as promising photocatalysts for sustainable wastewater purification. Among them, TiO₂–P25 (commercial TiO₂) is widely used; however, its wide band gap restricts visible light activity. A simple and eco friendly approach to overcome this limitation is the formation of heterostructures. In this work, TiO₂–P25/WO₃ heterostructures were synthesized via a rapid, additive free aqueous sonochemical route (10 min ultrasonication). The structural characteristics of the composites were examined by XRD, FTIR, Raman spectroscopy and FESEM, while their optical and interfacial properties were assessed by DRS, ζ potential and EIS analyses. These characterizations confirmed that the anatase–rutile TiO₂–P25 and monoclinic WO₃ phases remained intact without the appearance of new interfacial bonds, while close physical contact between the two oxides improved visible light absorption and facilitated interfacial charge transfer. The photocatalytic performance was evaluated in a spherical quartz reactor under real sunlight using methylene blue (MB) as a model pollutant. Response surface methodology with a central composite design was employed to investigate the effects of catalyst dose (0.5–1.5 mg/L), initial MB concentration (20–40 mg/L), and pH (5–9). Under the optimized conditions (20 mg/L MB, 1.5 mg/L catalyst, pH 9), 69.5% of MB was removed by dark adsorption within 30 min, and subsequent sunlight irradiation resulted in 94.6% total removal after 70 min, with a reaction rate constant of 0.042 min⁻¹. Taken together, these results demonstrate that this simple aqueous synthesis provides an efficient and eco friendly pathway to prepare TiO₂–P25/WO₃ photocatalysts for large scale wastewater remediation under real sunlight.
Research Paper
Seyed Hosein Arabfarashahi; Shahram Talebi
Abstract
In this paper the influence of the operational and geometrical parameters on the mixing and flow uniformity within an anaerobic digester is investigated. Anaerobic digestion is classified as single or multiphase flow reactor to produce biogas from processed organic waste. Within the digesters, mass transfer ...
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In this paper the influence of the operational and geometrical parameters on the mixing and flow uniformity within an anaerobic digester is investigated. Anaerobic digestion is classified as single or multiphase flow reactor to produce biogas from processed organic waste. Within the digesters, mass transfer is a key component to obtain an optimal process which is highly dependent on uniformity and turbulence of the flow. Two quantitative mixing criteria namely uniformity index and turbulence intensity are assessed to investigate the possibility of improving mixing characteristics of an operating digester. The effect of inlet velocity, draft tube flow presence, draft tube velocity magnitude and direction and inlet tube position have been investigated and compared to a validated base case. According to the finding both inlet velocity and inlet pipe position can noticeably affect the operation of the digester and proper tuning of the inlet velocity and also optimized pipe position can enhance the uniformity of the flow while inducing high turbulence within the digester. Furthermore, by adjusting the inlet pipe position, it is possible to improve the uniformity index and turbulence intensity by 44% and 40% respectively.
Review Paper
Mehwish Qaseem; Muhammad Yasir Khan; Muhammad Waseem Akhtar; Syed Zeeshan Abbass; Mehwish Altaf; Shakeel Ahmed; Muhammad Saquib Ali
Abstract
Distilleries produce substantial amounts of wastewater containing high concentrations of organic and inorganic pollutants, leading to serious environmental concerns. In Sindh, Pakistan, water resources are at risk owing to the inappropriate disposal of industrial distillery effluents, contaminating land ...
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Distilleries produce substantial amounts of wastewater containing high concentrations of organic and inorganic pollutants, leading to serious environmental concerns. In Sindh, Pakistan, water resources are at risk owing to the inappropriate disposal of industrial distillery effluents, contaminating land resources, water bodies, and groundwater. This has led to a notable increase in skin diseases and other health problems in Sindh, Pakistan. Therefore, effective and sustainable treatment strategies are required. We comprehensively reviewed the characteristics of sugar distillery wastewater from the Sindh region and highlighted its chemical composition, toxicity, and environmental impact. Conventional treatment methods often fail to achieve complete pollutant removal, necessitating the development of advanced alternatives. Nanomaterials, including nanoparticles, nanocomposites, and Nano-catalysts, have emerged as promising alternatives owing to their high surface areas, superior adsorption capacities, and reusability. This analysis examined a range of nanomaterials, such as metal oxides, carbon-based materials, and bio-inspired nanoparticles, and evaluated their potential for treating wastewater locally. This study aims to bridge the knowledge gaps and promote sustainable approaches for mitigating water pollution in the Sindh sugar distillery industry.
Research Paper
Maryam Ali Hussein; Haneen Waleed Hanna; Siham Kamel Mohammed Dawood; Ghazwan Salim Naamo; Riyam Alsammarraie; Saleh Mahmoudi; Ata Amini
Abstract
Multinational corporations, seeking to reconcile economic goals with environmental stewardship, have found themselves at the center of an engaging academic discourse; one that has increasingly examined the role of ethical governance in promoting corporate environmental sustainability. This study analyses ...
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Multinational corporations, seeking to reconcile economic goals with environmental stewardship, have found themselves at the center of an engaging academic discourse; one that has increasingly examined the role of ethical governance in promoting corporate environmental sustainability. This study analyses whether ethical integration positively correlates with proxies of environmental performance, including greenhouse gas (GHG) emissions mitigation, waste reduction, energy efficiency, and renewable energy adoption. Using a mixed research design—comprising descriptive statistics, multiple regression analysis, and structural equation modelling (SEM)—we find that organizations with strong ethical frameworks achieve significantly better environmental outcomes. Specifically, the Ethical Integration Index (EII) shows astrong correlation with waste reduction (r = 0.72), GHG emissions reduction (r =0.68), and energy efficiency improvement (r = 0.66). Regression results further indicate that EII explains up to 76% of the variance in waste reduction and 71% inGHG mitigation. SEM analysis confirms both direct effects and indirect effects mediated by innovation (λ = 0.52, p < 0.01) and regulatory compliance (λ = 0.47, p < 0.01). These findings emphasize the crucial role of ethical decision-making indriving corporate environmental responsibility, suggesting that corporations should incorporate ethical governance into sustainability endeavors. The study offers actionable insights for corporate policymakers, environmental regulators, andsustainability practitioners concerned with long-term sustainability transformations.
