Research Paper
Ali Akbar Zinatizadeh; Safoora Nazari; Parviz Mohammadi; Sirus Zinadini
Abstract
In recent years, water scarcity has posed significant challenges to oil refineries. The escalating water demands of developing oil refineries in pace with the progressively stringent environmental, economic, and technical regulatory and suitability constraints necessitate seeking sustainable water and ...
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In recent years, water scarcity has posed significant challenges to oil refineries. The escalating water demands of developing oil refineries in pace with the progressively stringent environmental, economic, and technical regulatory and suitability constraints necessitate seeking sustainable water and wastewater management strategies that encourage minimizing fresh water consumption through treated wastewater reuse. Thus, the main scope of the present study is to investigate a general procedure using innovative post treatment technologies in order to attain an almost zero discharge water management in real life - Kermanshah's oil refinery case study. The results obtained are proofs enough that the selected post treatment scenario can effectively minimize the overall fresh water demand. the selected post treatment scenario involving hybrid membrane technology (UF + RO) could result in overall fresh water savings of approximately 70% and 50%, respectively in summer and winter times of the year, proving the benefit of water management optimization.
Research Paper
Ali azizpor; ahmad rajabi; fariborz yosefvand; saeid shabanlou
Abstract
In this study, the discharge coefficient of triangular weirs was modeled using the combination of the adaptive Neuro-fuzzy inference system (ANFIS) and the genetic algorithm (GA). In this study, the genetic algorithm was implemented for increasing the efficiency of ANFIS by adjusting membership functions ...
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In this study, the discharge coefficient of triangular weirs was modeled using the combination of the adaptive Neuro-fuzzy inference system (ANFIS) and the genetic algorithm (GA). In this study, the genetic algorithm was implemented for increasing the efficiency of ANFIS by adjusting membership functions as well as minimizing error values. in order to examine the ability of the hybrid model the Monte Carlo simulations were used. In this study, the k-fold validation method (k=5) was applied to evaluate the capability of the mentioned models. Then, using the input values, six hybrid ANFIS-GA models were introduced. Based on the analysis of the modeling results, the superior model predicted the value of the discharge coefficient in terms of the flow Froude number, the vertex angle of the weir, the ratio of the weir length to its height, the ratio of the flow head to the weir height and the ratio of the channel width to the weir length. The values of Mean Absolute Percent Error (MAPE) and Root Mean Square Error (RMSE) for the superior model were calculated 1.647 and 0.016, respectively. Furthermore, investigation of the numerical results indicated that the Froude number is the most effective parameter in modeling the discharge coefficient. Then, the results of the superior hybrid model were compared with the ANFIS results and it was concluded that the superior model simulates values of the discharge coefficient with higher accuracy. ©2019 Razi University-All rights reserved.
Research Paper
Babak Sanahmadi; Majeid Heydari; Saeed Gohari; Saeid Shabanlou
Abstract
In this paper, the flow in the vicinity of rectangular side orifices placed in main channels is estimated by means of the FLOW-3D model. To reconstruct the flow free surface, the Volume of Fluid (VOF) approach is utilized. In addition, the standard k-ε and RNG k-ε turbulence models are ...
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In this paper, the flow in the vicinity of rectangular side orifices placed in main channels is estimated by means of the FLOW-3D model. To reconstruct the flow free surface, the Volume of Fluid (VOF) approach is utilized. In addition, the standard k-ε and RNG k-ε turbulence models are employed to predict turbulence flow. According to the results obtained from the numerical modeling, the RNG k-ε turbulence model has higher accuracy than the standard k-ε. The analysis of the numerical modeling results proved that this model forecasts the discharge coefficient of side weirs with suitable accuracy. On the other hand, the mean absolute percent error (MAPE) is calculated equal to 12.204%. Also, the maximum pressure is simulated near the main channel bed. Moreover, the minimum pressure is estimated near the flow free surface. Regarding the numerical simulations, the maximum turbulence energy state occurs near the inlet of the side orifice and by increasing the side orifice dimensions the flow field turbulence energy value increases.
Research Paper
Fayazeh Rabanimehr; Mehrdad Farhadian; Ali Reza Solaimany Nazar; Elham Sadat Behineh
Abstract
In photocatalytic microreactors the catalyst layer is obtained by integration of nanostructure films of semiconductors. One of these nanostructures that have a good photocatalytic activity is ZnO nanowires. The photocatalytic degradation of methylene blue in a continuous flow microreactor with ZnOnanowires ...
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In photocatalytic microreactors the catalyst layer is obtained by integration of nanostructure films of semiconductors. One of these nanostructures that have a good photocatalytic activity is ZnO nanowires. The photocatalytic degradation of methylene blue in a continuous flow microreactor with ZnOnanowires deposited film is simulated. A finite element model is developed using COMSOL Multiphysics version 5.3 software to simulate the microreactor performance. The kinetic law of the photocatalytic reaction is assumed to be Langmuir–Hinshelwood. The kinetic constants kLHa andK are determined 1.43 10-7 mol/m2.s and 7.5 m3/mol, respectively. The percent of average absolute deviation of the model in predicting the methylene blue outlet concentration obtained about 0.12% mol/m3. The model showed a very good agreement with the published experimental data. The effect of microreactor depth, methylene blue inlet concentration and flow rate on the methylene blue degradation is also investigated. The simulation results showed that the microreactor with shorter depth and lower values of inlet concentration and flow rate has higher efficiency. Thiele modulus and Damköhler number are both estimated lower than 1. It indicates that the photocatalytic reactions occur without internal and bulk mass transfer limitations.
Research Paper
Nazanin Niknezhad; Neda Azimi; Shahin Ahmadi
Abstract
The purpose of this study was numerical and experimental investigations on the influence of ultrasound on Cr (VI) removal from aqueous solution by adsorption onto activated carbon nanoparticles. The effect of key factors on Cr (VI) elimination like media pH, absorbent mass, initial concentration of Cr ...
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The purpose of this study was numerical and experimental investigations on the influence of ultrasound on Cr (VI) removal from aqueous solution by adsorption onto activated carbon nanoparticles. The effect of key factors on Cr (VI) elimination like media pH, absorbent mass, initial concentration of Cr (VI) and the location of ultrasound transducers were considered. To perform CFD modeling of ultrasound propagation, the vibrations of 1.7 MHz piezoelectric transducers (PZTs) were defined based on the dynamic mesh model. The experimental results indicated that by pH raising from 2 to 8, Cr (VI) removal efficiency had a decreasing trend and at pH=8, it had the lowest value. The adsorption rate increased by augmentation in the adsorbent mass (AM) due to enhancing its specific surface area. In comparison with using a shaker, the ultrasound showed lower needed contact time for Cr (VI) elimination at identical conditions. In addition, CFD results depicted that the acoustic streams were induced in the direction of ultrasound propagation, which is caused to reach the better mixing and Cr (VI) removal efficiency. Finally, the experimental data were adopted with the Langmuir and Freundlich isotherms. The comparison of these models showed that both models were well suited to experimental findings and the data compatibility with Langmuir model was greater.
Research Paper
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 an antifouling nanofiltration membrane for dye removal. To investigate the effect of the Fum-ANPs on nanofiltration performance, pure water flux ...
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Fumarate-Alumoxane nanoparticles (Fum-ANPs) incorporated PES nanofiltration membrane was fabricated via phase inversion to achieve favorable performance as an antifouling nanofiltration membrane for dye removal. To investigate the effect of the Fum-ANPs on nanofiltration performance, pure water flux and water contact angle measurements were carried out. 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 functionalities with water molecules made the membrane surface more hydrophilic. Hence, this 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. For investigating the antifouling behavior of the membranes, powder milk solution (8 g/l) were analyzed using a dead-end filtration apparatus. The results obtained from fouling analysis clearly demonstrated that the introduction of Fum-ANPs in the membrane matrix ameliorated the antifouling behavior of the resulting membrane. To study the performance of the Fum-ANPs incorporated PES membrane rejection of Direct red 16 dye was tested. The Direct red 16 rejection with the Fum-ANPs blended PES membrane was 99% while it was 88.2% for the bare membrane sample
Review Paper
Zahra Mohebi; Maryam Nazari
Abstract
Disposal of waste products and residuals into the natural water bodies can have fatal consequences for aquatic ecosystems, posing severe threats to natural habitats and human health. Natural treatment systems are the most suitable treatment technologies for various types of wastewaters, which has attracted ...
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Disposal of waste products and residuals into the natural water bodies can have fatal consequences for aquatic ecosystems, posing severe threats to natural habitats and human health. Natural treatment systems are the most suitable treatment technologies for various types of wastewaters, which has attracted much attention in recent years. Phytoremediation is a plant-based technique used to eliminate or recover surplus nutrients in contaminated environments. The use of aquatic plants in wastewater phytoremediation is very efficient due to they have a very significant ability for assimilating and degrading contaminants (e.g., nitrates, phosphates, and heavy metals). Phytoremediation is a relatively new technology that is considered as an operational, efficient, new, and environmentally friendly technology that is still in the early stages of development and optimization. Its application on a large scale is still limited. It should also be noted that a clear vision of this innovation should be taken into account and, accurate data should be made available to the public as it will enhance its efficiency as a manageable solution in the worldwide. Additionally, phytoremediation has been evaluated as a separate low-tech and environmentally friendly green option compared to the existing technologies. The present study attempts to review the recently published literature to explain phytoremediation technology and its advantages in purifying water and wastewater.
Review Paper
Nafise Jamialahmadi; Sepideh Rahimi; Ali Esmaeili
Abstract
Healthcare facilities are vital establishments to improve the public health, but with poor waste and wastewater management, may turn into a potential health risk. The fecal-oral transmission potential of SARS-CoV-2 and the role of the wastewater as a potential source of infection, more than ever highlights ...
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Healthcare facilities are vital establishments to improve the public health, but with poor waste and wastewater management, may turn into a potential health risk. The fecal-oral transmission potential of SARS-CoV-2 and the role of the wastewater as a potential source of infection, more than ever highlights the importance of proper wastewater management during the COVID-19 pandemic. This systematic review represents a picture of the current state of hospital wastewater (HWW) management in Iran; an upper-middle income country with a paucity of proper data concerning HWW management and further provides suggestions for hospital wastewater management during COVID-19 pandemic in the country. We reviewed 31 papers that published from 2005-2020 evaluated 163 hospitals from 82 cities and 17 provinces. Per capita HWW generation in Iran varies from 354 to 1892 liter per bed per day (839±363 liter.bed/day). BOD, COD and TSS in the raw HWW were in the range of 119-1270, 205-1611 and 58-464 mg/L, respectively. Total coliforms and/or total fecal coliforms were in the range of 105-108 (MPN/100 mL). 44.2% of hospitals had an active WWTP at the time of the study from which, only 15.3% complied with discharge standards. More than 55% of the hospitals in Iran use no disinfection, and less than 7% comply with the discharge requirements. HWW management in Iran is very poor and there has been no improvement in HWW management within the last decade. To best respond to this pandemic, responsible authorities should address wastewater management in hospitals.
Review Paper
Maryam Nazari; Zahra Mohebi
Abstract
Widespread use of pesticides and herbicides, and the contamination in river, lake and sea waters have been become a major environmental concern in recent years. A common example of such herbicides is atrazine and its derivatives, which have been widely used in recent years to control pests in agriculture ...
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Widespread use of pesticides and herbicides, and the contamination in river, lake and sea waters have been become a major environmental concern in recent years. A common example of such herbicides is atrazine and its derivatives, which have been widely used in recent years to control pests in agriculture and improve food production and meet the needs of the global population, which is increasing year by year. Most analytical methods are used to determine pesticides and herbicides in the environment which are usually highly reliable and sensitive, but they are often very complex and require advanced tools, and measurements should be performed directly in a lab. Atrazine electrochemical biosensors based on enzymatic biosensors, immunosensors, and aptasensors are reviewed in this study. For atrazine detection by enzymatic biosensors, tyrosinase commonly is used. Phenols and atrazine are the substrates and inhibitor of this enzyme, respectively. These enzymatic biosensors are based on sensing of decreasing current in the presence of atrazine. Immunosensors based on the analyte size generally categorized into two detection methods including competitive and noncompetitive that both of them were used for atrazine detection. The several aptamer sequences were used for atrazine aptasensing that could detect it in nano and picomolar concentrations.
