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Optimizing OLR and HRT in a UASB reactor for pretreating high- Strength municipal wastewater
, Article Chemical Engineering Transactions ; Volume 24 , 2011 , Pages 1285-1290 ; 19749791 (ISSN) ; Shayegan, J ; Sharif University of Technology
Abstract
This study was carried out for examination of a lab-scale UASB reactor for optimization of organic loading rate and hydraulic retention time. The total volume of the reactor was 5 1 with an effective height of 160 cm and diameter of 5 cm. This reactor was used to treat fortified municipal wastewater at volumetric organic loadings of 3.6, 7.2, 10.8, and 14.4 kg m3 d 1 at temperature 30°C. The result of present work indicated an optimum range for organic loading (7.2 to 10.8 kg m-3 d-1) with COD removal efficiency of about 85%. Moreover, optimum HRT for influent COD concentration of 1200mg/l is shown to be only 4 hours. Furthermore nitrate removal efficiency was about 80% at optimized organic...
Effect of adding nitrate on the performance of a multistage biofilter used for anaerobic treatment of high-strength wastewater
, Article Chemical Engineering Journal ; Volume 156, Issue 2 , 2010 , Pages 250-256 ; 13858947 (ISSN) ; Borja, R ; Bagheri, M ; Ali Monemian, S ; Goodarzi, V ; Tooyserkani, Z ; Sharif University of Technology
Abstract
This laboratory research was carried out to evaluate the performance of a multistage anaerobic biofilm reactor, with six compartments and a working volume of 70 L, for the treatment of a strong synthetic nitrogenous and high-strength wastewater at an operational temperature of 26 ± 0.5 °C. Initially, the performance of the reactor was studied when subjected to an increase in the hydraulic retention time (HRT) at a constant influent COD concentration of 10,000 mg/L. Five different HRTs were studied: 0.25, 0.67, 1, 3 and 5 days, which were equivalent to 6, 16, 24, 72 and 120 h, respectively. By increasing the HRTs from 6 h to 1 day, COD and BOD removal efficiencies were increased from 63% to...
Development of a novel graphene oxide-blended polysulfone mixed matrix membrane with improved hydrophilicity and evaluation of nitrate removal from aqueous solutions
, Article Chemical Engineering Communications ; 2018 ; 00986445 (ISSN) ; Nasseri, S ; Mahvi, A. H ; Nabizadeh, R ; Mousavi, S. A ; Maleki, A ; Alimohammadi, M ; Jafari, A ; Hemmati Borji, S ; Sharif University of Technology
Taylor and Francis Ltd
2018
Abstract
In this study, four types of mixed matrix membranes were fabricated using polysulfone (as the base polymer) and different contents of graphene oxide (GO) nanosheets (as modifier) through wet phase inversion method. Based on the amounts of GO (0, 0.5, 1, and 2 wt%), the synthesized membranes named as M1, M2, M3, and M4, respectively. The membranes characteristics were evaluated using FE-SEM, FT-IR, and water contact angle measurements. In addition, the performance of the prepared membranes was investigated in terms of basic parameters: filtrate water flux, nitrate removal efficiency, and antifouling properties. Results showed significant improvements of the characteristics of modified...
Development of a novel graphene oxide-blended polysulfone mixed matrix membrane with improved hydrophilicity and evaluation of nitrate removal from aqueous solutions
, Article Chemical Engineering Communications ; Volume 206, Issue 4 , 2019 , Pages 495-508 ; 00986445 (ISSN) ; Nasseri, S ; Mahvi, A. H ; Nabizadeh, R ; Mousavi, S. A ; Maleki, A ; Alimohammadi, M ; Jafari, A ; Hemmati Borji, S ; Sharif University of Technology
Taylor and Francis Ltd
2019
Abstract
In this study, four types of mixed matrix membranes were fabricated using polysulfone (as the base polymer) and different contents of graphene oxide (GO) nanosheets (as modifier) through wet phase inversion method. Based on the amounts of GO (0, 0.5, 1, and 2 wt%), the synthesized membranes named as M1, M2, M3, and M4, respectively. The membranes characteristics were evaluated using FE-SEM, FT-IR, and water contact angle measurements. In addition, the performance of the prepared membranes was investigated in terms of basic parameters: filtrate water flux, nitrate removal efficiency, and antifouling properties. Results showed significant improvements of the characteristics of modified...
Optimization of multistage biological nutrient removal reactors for removal of nitrogen and phosphorus from saline refinery wastewater
, Article International Journal of Environmental Science and Technology ; Volume 17, Issue 12 , 2020 , Pages 4865-4878 ; Borghei, S. M ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH
2020
Abstract
The present study aimed at investigating the biological treatment of nitrogen and phosphorus from the saline wastewater in various systems. In the end, moving bed biofilm reactor and anaerobic/anoxic/aerobic (AOA) were chosen as the best systems. In the present study, the investigations were carried out in two 24-h and 12-h retention times for three nitrogen concentrations, 200 mg/l, 300 mg/l, and 400 mg/l, two phosphorus concentrations, 14 mg/l and 20 mg/l, three Chemical oxygen demand (COD) concentrations, 800 mg/l, 1000 mg/l, and 1200 mg/l, and four salt concentrations, 10 g/l, 12 g/l, 17 g/l, and 20 g/l. The obtained results indicated that the COD removal percentage was high in a range...
Image Denoising Using Sparse Representation
, M.Sc. Thesis Sharif University of Technology ; Marvasti, Farokh (Supervisor)
Abstract
In this thesis, two novel image noise reduction approaches are proposed which can be implemented both in sparse signal processing domains such as learned dictionaries or wavelet and DCT. We first introduced a new probability density function (PDF) for the coefficients of image in transform domain and after that by using distinct thresholding function for each of coefficients we reduce noise in transform domain that is equivalent to reduce noise in time domain, since our transformation are unitary . In this scheme, we used variational approximation theory to find the optimum threshold values and noise variance simultaneously. In second method, we focus on impulsive noise reduction using...
Removal of Heavy Metal Ions and Wastewater Treatment by Using the Electrocoagulation Process
, M.Sc. Thesis Sharif University of Technology ; Ghasemian, Saloumeh (Supervisor)
Abstract
Industrial wastewater treatment has always been one of the significant human being problems for the years. In particular, sewage containing heavy metals that, if discharged into nature, would have irreversible effects on the ecosystem and human health. Due to their toxic nature, heavy metals will reduce the efficiency of wastewater treatment systems if they are not efficiently treated. Also, the removal of Nitrate from the wastewater, which is one of the most stable nitrogen oxides, has always been a serious human problem in the treatment of effluents due to their high solubility in water. The simultaneous presence of nitrate and heavy metals in the effluent will cause many problems in the...
Rapid removal of heavy metal ions from aqueous solutions by low cost adsorbents
, Article International Journal of Global Environmental Issues ; Volume 12, Issue 2-4 , 2012 , Pages 318-331 ; 14666650 (ISSN) ; Rohani Bastami, T ; Tahmasbi, M ; Zabihi, M ; Sharif University of Technology
Interscience
2012
Abstract
In the present investigation, different agricultural solid wastes namely: eggplant hull (EH), almond green hull (AGH), and walnut shell (WS), that are introduced as low cost adsorbents, were used for the removal of heavy metals (cobalt, strontium and mercury ions) from aqueous solutions. Activation process and/or chemical treatments using H 2O 2 and NH 3 were performed on these raw materials to increase their adsorption performances. The effectiveness of these adsorbents was studied in batch adsorption mode under a variety of experimental conditions such as: different chemical treatments, various amounts of adsorbents, initial metal-ion concentrations, pH of solutions, contact times, and...
Fluoride Removal from Sludge's of Evaporation Lagoons of Isfahan’s UCF Plant
, M.Sc. Thesis Sharif University of Technology ; Samadfam, Mohammad (Supervisor) ; Firouz Zare, Mahmoud (Co-Advisor) ; Ghasemi, Mohamad Reza (Co-Advisor)
Abstract
Nuclear energy is one of the most important sources of energy from the economical point of view and also in terms of cleanliness and safety. Hence, strategically, uranium is one of the most basic elements of the earth and nowadays, the importance of this element is more marked due to the nuclear industry developement. Therefore, uranium recovery from the wastes generated during nuclear fuel production in Isfahan’s uranium conversion plant- in which yellow cake is converted to uranium hexafluoride- is quite pivotal. In this experimental research, we have to remove Fluoride from waste after dissolution by several methods like precipitation. After that uranium is extracted from the sludge of...
Evaluation of Permeable Pavement in Removing Pollutants from Surface Runoff
, M.Sc. Thesis Sharif University of Technology ; Tajrishi, Masoud (Supervisor) ; Nazari Alavi, Alireza (Supervisor)
Abstract
Urbanization expansion increases impermeable surfaces and ultimately produces more runoff from urban surfaces. The runoff in the urban streets moves the pollution with high levels from the city and then collects into channels where they are transported into the water courses. The most important factor in runoff polluting is sediments. If you remove sediments from runoff, their quality will be improved. One of the effective systems to reduce sediments from the surface runoff is permeable pavement. In this study a simulator system is used. The sample of permeable pavement analysed consisted of two layers of geotextile beddig, filter granular layer (2.36 to 4.75mm), subbase granular layer (4.75...
Removal of Non-Metallic Inclusions from Steel by Electromagnetic Levitation Melting in a Slag
, M.Sc. Thesis Sharif University of Technology ; Halali, Mohammad (Supervisor)
Abstract
In this study, industrial steel (DIN 17135) underwent a new purification process with the aim of removing non-metallic inclusions and producing clean steel. Samples of steel were levitated in synthetic slag from the CaO-CaF2-Al2O3 system by an electromagnetic field. The effect of time, temperature and slag composition factors on the inclusions content of sample has been investigated. The images of the optical microscope were evaluated according to the ASTM E 45 standard, which according to the extracted results, the removal process was done to the desired extent. On the other hand, as the time and temperature of the process and the weight percentage of CaF2 increase, the number and size of...
Experimental Study of Biological Removal of Cyanides in the Effluent of Coke Oven of Esfhan Steel Company
, M.Sc. Thesis Sharif University of Technology ; Yaghmaei, Soheila (Supervisor)
Abstract
The presence of highly toxic cyanides in the effluent of coke oven of steel industries is considered as a critical problem. Owing to high levels of toxicity, control and removal of cyanide are of great importance in this industry. Biological removal of cyanides by indigenous microorganisms offers inexpensive, safe and environmentally compatible option in comparison with chemical and physical methods. The present study primarily focused on the isolation and purification of the microorganisms which utilize cyanide as the sole source of Nitrogen in alkaline conditions. The isolated bacterial strains were investigated through variety of bacteriological and biochemical reactions as well as...
Direct dyes removal using modified magnetic ferrite nanoparticle
, Article Journal of Environmental Health Science and Engineering ; Vol. 12, Issue. 1 , 28 May , 2014 ; ISSN: 2052336X ; Abdi, J ; Bastani, D ; Sharif University of Technology
Abstract
The magnetic adsorbent nanoparticle was modified using cationic surface active agent. Zinc ferrite nanoparticle and cetyl trimethylammonium bromide were used as an adsorbent and a surface active agent, respectively. Dye removal ability of the surface modified nanoparticle as an adsorbent was investigated. Direct Green 6(DG6), Direct Red 31 (DR31) and Direct Red 23 (DR23) were used. The characteristics of the adsorbent were studied using Fourier transform infrared (FTIR), scanning electron microscopy (SEM) and X-ray diffraction (XRD). The effect of adsorbent dosage, initial dye concentration and salt was evaluated. In ternary system, dye removal of the adsorbent at 90, 120, 150 and 200 mg/L...
Biodegradation of phenol from a synthetic aqueous system using acclimatized activated sludge
, Article Arabian Journal of Geosciences ; Volume 6, Issue 10 , 2013 , Pages 3847-3852 ; 18667511 (ISSN) ; Doulati Ardejani, F ; Marandi, R ; Rafiee pur, S ; Sharif University of Technology
2013
Abstract
Phenol is one of the aromatic hydrocarbons. Phenol and its derivatives are highly toxic. These pollutants can be observed in the effluents of many industries. This research investigates the removal of phenol by the use of activated sludge in a batch system. The effects of influencing factors on biodegradation efficiency have been evaluated. The main factors considered in this study were the volume of acclimatized activated sludge inoculation, pH, temperature, and initial concentration of phenol. The inoculation volumes of 1, 3, and 5 mL of acclimatized activated sludge were taken into account. Different pH values of 3, 5, 7, 9, and 11 were examined. The experiments were conducted for...
Optimization of conditions in ultrafiltration treatment of produced water by polymeric membrane using Taguchi approach
, Article Desalination and Water Treatment ; Volume 51, Issue 40-42 , 2013 , Pages 7499-7508 ; 19443994 (ISSN) ; Rekabdar, F ; Hemmati, M ; SafeKordi, A. A ; Ahmadi, M ; Sharif University of Technology
Desalination Publications
2013
Abstract
In this study, the ultrafiltration of produced water was studied using a two-stage ultrafiltration process. In the first stage, the influences of operating parameters, including transmembrane pressure, temperature, and cross-flow velocity on the amount of flux decline caused by membrane fouling, were investigated using a polymeric membrane. In order to design the experiments and optimize the experimental results, the Taguchi method was applied. L9 (33) orthogonal array for experimental planning and the smaller-the-better response category was selected to obtain optimum conditions because the lowest flux decline was our aim. Analysis of variance was used to determine the most important...
Artificial neural network modeling for predict performance of pressure filters in a water treatment plant
, Article Desalination and Water Treatment ; Volume 39, Issue 1-3 , Feb , 2012 , Pages 192-198 ; 19443994 (ISSN) ; Gholikandi, G. B ; Hazrati, H ; Sharif University of Technology
Taylor and Francis Inc
2012
Abstract
Pressure filters are popular in small municipal water treatment plants. One of the principles for designing and using the various units of water treatment plants is the ability of assigning and predicting the performance of those units under different and various conditions that could be verified by making pilot scale tests and could be modeled by means of available programs and software such as artificial neural network. The goals of this study that was conducted to predict pressure filter efficiency are: (1) evaluations of pressure filter efficiency for turbidity removal under different conditions such as turbidity of raw water, filtration rate and filter pressure changes; (2) statistical...
An artificial neural network model for the prediction of pressure filters performance and determination of optimum turbidity for coli-form and total bacteria removal
, Article Journal of Environmental Studies ; Volume 37, Issue 60 , 2012 , Pages 129-136 ; 10258620 (ISSN) ; Hazrati, H ; Rostamian, H ; Sharif University of Technology
2012
Abstract
In water treatment processes, because of complicated and nonlinear relationships between a number of physical, chemical and operational parameters, using analytical models with the ability to capture underlying relationships using examples of the desired input-output mapping is quite suitable. Artificial Neural Networks (ANN) has been increasingly applied in the area of environmental and water resources engineering. The main advantage of Artificial Neural Networks over physical-based models is that they are data-driven. The purpose of this research is to study the performance of pressure filters on turbidity removal from water according to several parameters such as turbidity, filtration...
Biofiltration of hexane vapor: Experimental and neural model analysis
, Article Clean - Soil, Air, Water ; Volume 39, Issue 9 , 2011 , Pages 813-819 ; 18630650 (ISSN) ; Halladj, R ; Saber, M ; Ferdowsi, M ; Nasernejad, B ; Sharif University of Technology
Abstract
Biofiltration is a commonlypracticed biological technique to remove volatile compounds from waste gas streams. From an industrial view-point, biofilter (BF) operation should be flexible to handle temperatures and inlet load (IL) variations. A compost BF was operated at different temperatures (30-45°C) and at various inlet loading rates (ILR; 8-598gm -3h -1) under intermittent loading conditions. Complete removal of n-hexane was observed at 30 and 35°C at ILRs up to 330gm -3h -1. Besides, 20-75% of the pollutant was removed at 40°C, corresponding to the different ILs applied to the BF. Increasing the temperature to 45°C decreased the removal efficiency (RE) significantly. A feed forward...
A technical and economic assessment of variants for CO 2 separation from synthesis gas
, Article 19th International Congress of Chemical and Process Engineering, CHISA 2010 and 7th European Congress of Chemical Engineering, ECCE-7, 28 August 2010 through 1 September 2010, Prague ; 2010 ; Nouri Khorasani, A ; Baghalha, M ; Pazos Costa, A ; Sharif University of Technology
2010
Abstract
CO 2 removal from synthesis gas to reduce emission in the atmosphere was studied using physical absorption with the Selexol solvent. Variances of 2-5 separator units and various pressure drop patterns were utilized. Simulation results showed that the case with 4 separators and uniform pressure drop distribution leads to the optimum design, in terms of capital and operational expenditures. Since the cost model for compressors, heat exchangers and coolers is a direct function of energy consumed, the capital expenditure was optimized simultaneously with operational expenditure, and the CAPEX/OPEX analysis reflects this matter as well. This is an abstract of a paper presented at the 19th...
Vacuum enhanced membrane distillation for trace contaminant removal of heavy metals from water by electrospun PVDF/TiO2 hybrid membranes
, Article Korean Journal of Chemical Engineering ; Volume 33, Issue 7 , 2016 , Pages 2160-2168 ; 02561115 (ISSN) ; Monfared, S. M ; Amini, Y ; Dastbaz, A ; Sharif University of Technology
Springer New York LLC
Abstract
Electrospun hybrid membranes were synthesized using electrospinning of Poly (vinylidenefluoride) - titanium tetraisopropoxide (PVDF-TTIP) sol. Asymmetric post-treatment of membrane conducted for deprotonation of titanate and making hydrophilic/hydrophobic dual characteristics. The membranes were characterized by various methods such as wettability, scanning electron microscopy, infrared spectroscopy, X-ray diffraction and liquid entry pressure tests. For evaluating the separation performance, these membranes were applied in the VMD process to treat water heavy metal contaminants. The effects of operating parameters such as flow rate, temperature and membrane properties as porosity, on...