Laraib Pervaiz Akhter; Hamza Farooq Gabriel; Sajjad Haider; Shatirah Akib
Abstract
The paper narrates a study of a numerical model taken into consideration to explore the overall hydraulic performance of Constructed wetland located at NUST H-12 Campus, Islamabad. The governing equations of flow in wetland ponds and the transport particle were solved using COMSOL Multiphysics 5.0. In ...
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The paper narrates a study of a numerical model taken into consideration to explore the overall hydraulic performance of Constructed wetland located at NUST H-12 Campus, Islamabad. The governing equations of flow in wetland ponds and the transport particle were solved using COMSOL Multiphysics 5.0. In this study, the simulation of the model is done to find the dead spaces and short-circuiting in the wetland along with providing remedial measures to reduce the dead spaces. The comparison of two turbulent models i.e. K-ω and K-ε were also made to depict the velocity of wetland and the particle tracer study was also conducted to find the behavior of wetland. The model was simulated with experimental data and the results revealed that 15% to 20% area of wetland is experiencing short-circuiting. Alternative wetland designs were suggested for the same flow condition. The K-ω model was considered to be more suitable due to the limitation of K-ε model.
Elham Chiani; Seyed Naser Azizi; Shahram Ghasemi; Salma Ehsani Tilami
Abstract
Today, many efforts have been made to use agricultural waste as a cheap and abundant resource for providing suitable adsorbents to remove pollutants such as industrial dyes. The aim of this study was to remove dye from water under different conditions using SBA-15 nano particles as adsorbents their silica ...
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Today, many efforts have been made to use agricultural waste as a cheap and abundant resource for providing suitable adsorbents to remove pollutants such as industrial dyes. The aim of this study was to remove dye from water under different conditions using SBA-15 nano particles as adsorbents their silica was prepared from stem sweep ash (SSA). Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD) and N2 adsorption experiments were applied to evaluate the structural characteristics of obtained adsorbent. In addition, to remove Azure B dye by SBA-15, the optimal values were obtained as the parameters of contact time = 30 min, pH = 8, temperature = 65 °C, adsorbent amount = 0.01 g, stirring rate = 90 rpm and initial dye concentration = 100 mg/L. The kinetic and thermodynamic experiments were conducted on the adsorption process as well. The results of the experiments demonstrated that the total surface area and total pore volume of the adsorbent were 780 m2/g and 0.8483 cm3/g, respectively. Moreover, the surface adsorption process of Azure B followed the Langmuir's isothermal model, and kinetic data followed the surface adsorption of pseudo-second-order kinetic model. Besides, the values of ΔH° and ΔS° were 5409.32 j/mol and 37.28 j/mol K, respectively, and the maximum adsorption capacity of adsorbent was 166.66 mg/g.
Bouchenak Khelladi Racha Medjda; Chiboub Fellah Abdelghani; Pontié Maxime; Guellil Fatima Zohra
Abstract
This review paper will serve to explain how a particle is trapped on a porous media, and describe the mobility of those particles when passing through a media. It also presents the different parameters that play an important role on the trapping mechanism and the role of biofilm formation. The deposition ...
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This review paper will serve to explain how a particle is trapped on a porous media, and describe the mobility of those particles when passing through a media. It also presents the different parameters that play an important role on the trapping mechanism and the role of biofilm formation. The deposition and trapping mechanism of particles in porous media is governed by the action of different mechanisms such as interception, sieving, diffusion, gravitational and Van Der Waals forces, Brownian diffusion, and inertia. The particle retention through the porous media leads to the formation of a biofilm and the clogging of the media. The understanding of particle retention, clogging, and biofilm formation is interesting because it plays a major role in soil recovery process such as bioremediation, biosorption and filtration (on sand and activated carbon) used for degradation of particles (colloids and microorganisms) and harmful contaminants (heavy metals, drugs) by microorganisms.
Salma Ajeel Fenjan; Ali Akbar Akhtari; Mohammad Hadi Tavana
Abstract
In this study, the performance of vertical and tilted crown weirs with different angles of the weir crest across the flow has been investigated using numerical and experimental models. Accordingly, various experiments are conducted on tilted crown sharp-crested weirs under different free-flow conditions. ...
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In this study, the performance of vertical and tilted crown weirs with different angles of the weir crest across the flow has been investigated using numerical and experimental models. Accordingly, various experiments are conducted on tilted crown sharp-crested weirs under different free-flow conditions. Moreover, computational fluid dynamic (CFD) modeling has been done using Fluent software to determine the best form of the discharge coefficient (Cd). In this study, the RNG model is used to define turbulence in the fluid flow and the two-phase volume of fluid (VOF) method is applied to define the interface of water-air in the flume. To verify the accuracy of the CFD model, the experimental data that was done in this research are used. Moreover, another goal of this research is to investigate the influence of the different angles of weir on hydraulic characteristics of flow such as pressure, velocity and Cd parameters. The results show that by increasing the weir crest angle across the flow (α), the Cd values are almost constant. Furthermore, the numerical results are in good agreement with the experimental models. As, the comparison of numerical and experimental data shows that the maximum absolute relative error (ARE) obtained are 2.8 %, which indicates the high accuracy of the CFD model. The vortex area with return velocity vectors can be seen in downstream of the weir and these vectors increase near the weir. In all velocity values, by decreasing the angle of weir to the flow direction, the Cd values increased and tends to a constant value while, the pressure values decreased. As for the velocity values in ranges of 0.05-0.23 m/s, the Cd value is ranged in 0.64-0.675. Finally, as the Reynolds and Froude number increase, the discharge coefficient decreases and tends to a constant number of 0.65 approximately.
Madineh Sadeghipour; Mehdi Kheirmand; Azar Asadi
Abstract
This research focused on improving the antifouling properties and rejection performance of polyetherimide (PEI) nanofiltration membrane by chemical surface modification (surface coating). The hydrophilicity of the PEI nanofiltration membrane’s surface was enhanced by anchoring guanidine on its ...
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This research focused on improving the antifouling properties and rejection performance of polyetherimide (PEI) nanofiltration membrane by chemical surface modification (surface coating). The hydrophilicity of the PEI nanofiltration membrane’s surface was enhanced by anchoring guanidine on its surface which the used dosage of guanidine wasconsidered as a variable (0.5, 1, and 1.5 g/L of guanidine concentration). ATR-FTIR, SEM, AFM, and water contact angle were used to characterize the surface-modified membranes. Also, dry milk powder solution was considered as an organic foulant to assess antifouling features of the fabricated membranes. According to the obtained results, the surface modified membrane with 0.5 g/L of guanidine concentration was the optimal surface-modified membrane with pure water flux (PWF) and flux recovery ratio (FRR) of 11.6 kg/m2.h and 88.8%, respectively. Moreover, the capabilities of the optimal surface-modified membrane and the pristine membrane for rejecting AS5+ and Hg2+ in aqueous solution with concentrations of 20 ppm and 50 mg/L were compared. Based on the obtained results, the optimal surface-modified membrane rejected more than 98.5 % of AS5+ and Hg2+ solutions with 20 and 50 mg/L of metal ion concentrations.
Mohamad Reza Madadi
Abstract
Reservoir sedimentation is a serious challenge in many regions of the world and has severe consequences for water management, flood control, and generation of energy. The purpose of this paper is providing a valuable source of information on the reservoir sedimentation problem and reviewing the existing ...
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Reservoir sedimentation is a serious challenge in many regions of the world and has severe consequences for water management, flood control, and generation of energy. The purpose of this paper is providing a valuable source of information on the reservoir sedimentation problem and reviewing the existing control strategies utilized globally against it. A wide range of sedimentation related problems were outlined. Different sediment management strategies were investigated with their main advantages and disadvantages. Special attention was devoted to the flushing technique as the most effective way of preserving the reservoirs’ storage capacity. As the main novelty of this study, a series of innovative complementary methods to improve the efficiency of sediment removal during the flushing operation was introduced. Based on the analysis, each sediment management strategy may be advantageous under certain circumstances, and successful implementation of such strategies needs regular monitoring and comprehensive recognition of the effective factors. The use of initiative structural methods, including those cited in this article, although they improve the flushing efficiency, they may come with some limitations that should be considered in practice. It is strongly recommended that such structural methods be taken into account in the first phases of dams’ design because they may influence the layout of dam structures. As conclusion, it was found that the progress is being made in successfully reducing and managing of sedimentation at reservoirs. New methods in combination with the flushing operation demonstrated significant performance in sediment removal from the reservoirs and restoring the corresponding storage. The study of this paper is recommended to interested researchers, dam owners, and water resources authorities.
Golshan Moradi; Sirus Zinadini; Masoud Rahimi
Abstract
Fumarate-alumoxane nanoparticles (Fum-ANPs) incorporated PES nanofiltration membrane was fabricated via phase inversion to achieve favorable performance as the enhancement in the dye removal and antifouling capacity. FTIR spectra of the Fum-ANPs revealed that the carboxylate and hydroxyl functional groups ...
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Fumarate-alumoxane nanoparticles (Fum-ANPs) incorporated PES nanofiltration membrane was fabricated via phase inversion to achieve favorable performance as the enhancement in the dye removal and antifouling capacity. FTIR spectra of the Fum-ANPs revealed that the carboxylate and hydroxyl functional groups were created on the surface of Fum-ANPs. The strong affinity of Fum-ANPs functional groups with water molecules made the membrane surface more hydrophilic. Hence, the modified membrane sample had a higher pure water flux than the bare one. Zeta potential data showed that the Fum-ANPs blended PES membrane was negatively charged at a pH value of 6, which is favorable for negatively charged solute rejection. The antifouling behavior of the membranes was analyzed using powder milk solution (8 g/L) in a dead-end filtration system. The obtained results demonstrated that the introduction of Fum-ANPs in the membrane matrix ameliorated the antifouling behavior of the resulting membrane. To further study the performance of the Fum-ANPs incorporated PES membrane, removal of Direct red 16 dye was tested. The removal efficiency of Direct red 16 with the Fum-ANPs blended PES membrane was 99% while it was 88.2% for the bare membrane sample.
Golshan Moradi; Sirus Zinadini; Masoud Rahimi
Abstract
The research on membrane-based filtration technology for water treatment has expanded in recent years. Membrane fouling is a major challenge that decreases the permeability and decreases the lifetime and selectivity of the membrane. Recently, it was found that fouling mitigation and better control of ...
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The research on membrane-based filtration technology for water treatment has expanded in recent years. Membrane fouling is a major challenge that decreases the permeability and decreases the lifetime and selectivity of the membrane. Recently, it was found that fouling mitigation and better control of membrane fouling can be attained under the application of the electric field. This paper provides an overview of the application of the electric field to the filtration process and its antifouling mechanism. Utilization of conductive polymeric membranes and application of electric field in membrane bioreactors are reviewed as well. The presented review demonstrates that the introduction of negative charge into the membrane surface via preparing conductive membranes or applying an external electric field onto the membrane surface suggests several advantages. These are fouling alleviation, better control of membrane fouling, an increase of membrane resistance to cake deposition on the membrane surface, and superior possible applications such as better salt rejection and antibacterial activity.
Nasim Saniei; Nahid Ghasemi; Ali Akbar Zinatizadeh; Sirus Zinadini; Majid Ramezani
Abstract
Graphene oxide has attracted many interests in the recent decade due to its unique mechanical and chemical properties. This study focuses on the modification of graphene oxide and preparation proton exchange membrane (PEM) by sulfonated poly ether ether ketone (SPEEK) as base polymer for using in MFC ...
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Graphene oxide has attracted many interests in the recent decade due to its unique mechanical and chemical properties. This study focuses on the modification of graphene oxide and preparation proton exchange membrane (PEM) by sulfonated poly ether ether ketone (SPEEK) as base polymer for using in MFC as a modified membrane to remove COD and electricity generation. The scanning electron microscope (SEM) images, Fourier transform infrared (FTIR) and contact angle measurements were used to verify hydrophilic properties of the synthesized membranes. First, preparation procedures and properties of sulfonated reduced graphene oxide are briefly described. Subsequently, modification of proton exchange membrane from SPEEK polymer with prepared nano particle of sulfonated reduced graphene oxide 0.5 wt. % and its operation in MFC was considered. COD removal, power density, current density and coulombic efficiency were monitored during the process operation to evaluate the MFC performance. During the process operation, COD removal, power density, current density, and coulombic efficiency were tracked to assess the MFC performance. The power density and current density, 39.43 mW/m2 and 161 mA/m2 and the columbic efficiency 48.9 % was obtained, respectively. The COD removal of 89.5 % was obtained.
Maryam Ansari; Iraj Jabbari
Abstract
The importance of water shortage in arid and semi-arid regions is more evident due to the limitation of water resources, and the preparation of water resources is necessary to protect and reduce the vulnerability of these resources. Therefore, in this study, considering the vulnerability of water and ...
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The importance of water shortage in arid and semi-arid regions is more evident due to the limitation of water resources, and the preparation of water resources is necessary to protect and reduce the vulnerability of these resources. Therefore, in this study, considering the vulnerability of water and soil resources in arid and semi-arid regions and the geographical structure of Zagros inland basins, the Izadkhast plain from the south of Fars province was selected to investigate the vulnerability of water resources. For this purpose, six parameters of water depth, net feed, aquifer environment, soil texture, topography, and hydraulic conductivity of the aquifer were analyzed using the DRASTIC model. The results showed that almost 50% of the plains were in the high vulnerability class, and 28% were in the very high vulnerability class. In the east and center of the plain, places with high vulnerability to pollutants and contaminated water were found. The effect of the formations in the east of the basin can be seen because, at the outlet of the rivers in the east of the basin, the amount of sulfate has increased dramatically, which indicates the presence of evaporate formations with gypsum. In the center of the basin, the heavy texture of the soil, the low slope, and the accumulation of most of the water entering the basin, some of which have a lot of salts, have increased the vulnerability of this part. Another result of this study is that the DRASTIC model has high efficiency in evaluating vulnerabilities similar to this research.
Ahmad Naeemah Bashara; Farhad Qaderi
Abstract
Due to the rapid population and economic growth, the demand for water has increased. In addition, the natural resources are limited and degrade because of several factors such as the climate change. These challenges lead to reduce the ability of providing water at the required quantity and quality. One ...
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Due to the rapid population and economic growth, the demand for water has increased. In addition, the natural resources are limited and degrade because of several factors such as the climate change. These challenges lead to reduce the ability of providing water at the required quantity and quality. One of solutions to maintain the sustainability of water supply from different sources is reuse of wastewater. For this aim, it is crucial to optimize wastewater systems. This research paper aims to describe different modelling possibilities and optimization methods for various components of integrated urban wastewater systems. The main conclusion of this research paper is the lack of study of optimum design and operation of urban wastewater systems in a holistic method. Moreover, most of previous studies on integrated wastewater management have been conducted on combined sewer systems.
Parastoo Yavari; Ali Akbar Akhtari; Arash Azari
Abstract
In the operation of water distribution networks in cities, leakage from pipes always causes problems for human health and for the environment. Leakage openings in pipes may exist in different shapes. Circular holes are common in corroded and punched pipes. In the leakage studies, the area of these openings ...
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In the operation of water distribution networks in cities, leakage from pipes always causes problems for human health and for the environment. Leakage openings in pipes may exist in different shapes. Circular holes are common in corroded and punched pipes. In the leakage studies, the area of these openings is usually assumed to be fixed and the leakage exponent is about 0.5. In this study, an analytical equation has been presented with two purposes. First, Examining the changes in the leak area and leakage exponent of circular holes. Second, providing an equation that contains more parameters than the general leakage equations. By using such an equation, the accuracy of leakage estimation is increased due to the direct involvement of the effective parameters. Also, for the possibility of modeling different leakage equations, including the present equation, a new hydraulic analysis model has been developed. This model tries to improve leakage modeling by including more capabilities than the existing hydraulic analysis models. Results showed that the leak area in circular holes is not fixed and changes due to different parameters. Comparison of the present equation and the orifice equation showed a significant difference which confirms that the orifice equation cannot be always used for circular leaks. In the study of leakage exponent, it was found that for polyethylene pipes, the leakage exponent is higher than value of 0.5 mentioned in the other studies and it can take different values depending on the leakage position in the network. Increasing the hole diameter did not affect the leakage exponent, but increased the leakage coefficient. On the other hand, for steel pipes, the leakage coefficient was fixed and the exponent remained around 0.5. Finally, the results showed the usefulness of the developed hydraulic analysis model for implementing the scenarios defined in this study.
Seyed Mehdi Sajjadi
Abstract
Treatment of wastewater is a crucial step in reducing pollution from the textile and dyeing industries. One of the best techniques for dye removal is photocatalytic processes, and TiO2 is frequently employed in numerous wastewater treatment applications. In this study, different adsorption isotherm models ...
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Treatment of wastewater is a crucial step in reducing pollution from the textile and dyeing industries. One of the best techniques for dye removal is photocatalytic processes, and TiO2 is frequently employed in numerous wastewater treatment applications. In this study, different adsorption isotherm models and experimental data from the removal of the methylene blue dye from wastewater by applying GO/TiO2/SiO2 nanocomposite were compared. The correlation coefficient values (R2) for the Langmuir isotherm type 1 (Hanes-Woolf), Temkin, and Freundlich were determined to be, respectively, 0.9957, 0.9823, and 0.9515. Additionally, the R2 values for the Redlich-Peterson, Sips, and Toth isotherms models were 0.9575, 0.9626, and 0.9629, respectively. Therefore, Langmuir isotherm type 1 has the highest R2 and is the best model for surface adsorption of methylene blue on GO/TiO2/SiO2 photocatalyst. As a result, monolayer adsorption was most likely dominating during the adsorption. Furthermore, this photocatalyst proved suitable for lower methylene blue concentrations and systems with lower temperature sensitivity.
Jaber Aazami; Sharif Joorabian Shooshtari
Abstract
Wetlands, as temporary or permanent water reservoirs, provide various benefits for the ecosystem, such as water supply, waste water treatment, and dust control. By the end of 2023, the Iranian government and the Ramsar Convention have registered 25 international and 226 national wetlands. West Azerbaijan ...
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Wetlands, as temporary or permanent water reservoirs, provide various benefits for the ecosystem, such as water supply, waste water treatment, and dust control. By the end of 2023, the Iranian government and the Ramsar Convention have registered 25 international and 226 national wetlands. West Azerbaijan and Mazandaran provinces have more wetland ecosystems than any other provinces. Semnan, Yazd, and Zanjan provinces have no wetlands. According to the Ramsar Convention of 1971, Iran has 32 aquatic ecosystems that have the potential to become wetland. In addition, according to the available data and the WHO standard, eight wetlands have the highest probability of producing dust and should be given more attention and care. We recommend the wetland management plan, which ensures their water requirements, protects them from degradation and pollution, and promotes their ecological restoration. Satellite image analysis can help explore how climate change affects dust intensity, considering the role of wetlands in dust control.
Zahra Fadaei; Kurosh Rad-Moghadam; Parvaneh Pakravan
Abstract
This study explored the efficacy of a cost-efficient activated carbon (AC) derived from natural bitumen through chemical activation with phosphoric acid. The objective was to evaluate bitumen-based activated carbon (AC) potential as a novel adsorbent by integrating Cu (NO3)2.3H2O onto AC for the removal ...
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This study explored the efficacy of a cost-efficient activated carbon (AC) derived from natural bitumen through chemical activation with phosphoric acid. The objective was to evaluate bitumen-based activated carbon (AC) potential as a novel adsorbent by integrating Cu (NO3)2.3H2O onto AC for the removal of harmful dyes from water-based solutions. Assessments of the adsorption capabilities of Cu@AC were conducted using representative samples of cationic and anionic dyes, namely methylene blue (MB) and methyl orange (MO). The incorporation of Cu onto the AC, leading to the formation of Cu@AC, resulted in a significant enhancement of the adsorption capacity of AC. The adsorption capacity of Cu@AC was measured using Brunauer–Emmett–Teller (BET) and iodine number measurements, with the most optimal Cu@AC sample exhibiting a BET surface area of 611 m2/g. Surface chemical properties were analyzed through FT-IR spectroscopy, while the microstructure of the produced Cu@AC was examined using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The efficiency of the adsorption process was influenced by factors such as pH, initial dye concentration, adsorbent dosage, and contact time. The most effective processing conditions for dye removal were determined as pH 11 for MB and pH 5 for MO, with an initial concentration of 25 mg/L, a 0.5 g/L adsorbent dosage, and a temperature of 333 K for a duration of 90 min. Under these optimized conditions, removal efficiencies exceeded 90% for MO and 80% for MB. The results demonstrated that Cu@AC has the potential to function as a cost-effective alternative to commercially available activated carbons for efficiently eliminating dyes from contaminated water.
Behzad Hossieni; Somayeh Sohrabi; Faranak Akhlaghian
Abstract
Inexpensive and new adsorbents, which are produced by processing the abundant agricultural by-products, can provide an efficient solution for a cleaner environment. The occurrence of heavy metals in water may pose a significant threat to human health. In this work, the processed date kernels are used ...
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Inexpensive and new adsorbents, which are produced by processing the abundant agricultural by-products, can provide an efficient solution for a cleaner environment. The occurrence of heavy metals in water may pose a significant threat to human health. In this work, the processed date kernels are used to remove chromium (VI) and iron (III) from water. The XRD, FTIR, SEM, VSM and EDX techniques are used to characterize the adsorbents. The equilibrium adsorbent dose for iron is 2 g/L while for chromium (VI) it is 4 g/L and the equilibrium time is 20 min. Moreover, acidic conditions favored the adsorption for both targets. The adsorption experiments showed that the kinetics of adsorption of chromium (VI) and iron (III) on date kernel powder fitted the pseudo-second-order model. The optimum adsorption capacities for iron (III) and chromium (VI) are 10.5 mg/g and 0.66 mg/g, respectively. In the meantime, the remarkable efficiency of the date kernel-based adsorbent for iron (III) removal paves the way for designing new magnetic adsorbents.
Hajar Esnaashari; Narges Ganjali; Ali Sardar Shahraki
Abstract
Water is one of the most basic environmental resources and plays an important role in human life. The Sistan river is the only source of water supply in this area and is completely dependent on the border river of Hirmand. The water of this river fluctuates greatly due to the interference of the country ...
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Water is one of the most basic environmental resources and plays an important role in human life. The Sistan river is the only source of water supply in this area and is completely dependent on the border river of Hirmand. The water of this river fluctuates greatly due to the interference of the country of Afghanistan, climate changes and the existence of Hamon international wetland, which has made the issue of decision-making regarding the management of water resources in Sistan region more than in other regions. This study, using the WEAP model, deals with modeling the effects of changes made in the water resources system in the Sistan region, which has special weather conditions. The results of this study showed that policies implemented in recent years have a positive effect on increasing water resources and decreasing water shortages in agriculture, drinking water, and the environment sectors, and supply-side policies combined with demand-side policies like increasing irrigation efficiency and reducing the per capita consumption of water can have a greater effect on economic, social and environmental development. It was also found that domestic water needs were met in all months, but in the agricultural sector, only 20% of agricultural water was provided to farmers in the summer months. Therefore, based on field observations, the agricultural sector is facing more problems in supplying water to the regions. Finally, for environmental needs, 184,000 cubic meters of water needed by Hamon Hirmand has not been supplied.
