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activated-sludge
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Upgrading Activated Sludge Study System by Introducing Moving Carriers
, M.Sc. Thesis Sharif University of Technology ; Borghei, Mehdi (Supervisor) ; Mosleh Abadi, Moslehi (Co-Advisor)
Abstract
In this study, the use of a fixed bed of the Kaldnes commercial carrier in the activated sludge system has been investigated. In this way, at zero time, a submerged fixed bed of Kaldnes was placed into a completely mixed activated sludge reactor and its various parameters were investigated during the time. During the experiment, the fixed bed (Kaldnes carriers enclosed in a lace) with 20, 35 and 50 percentage of volumes were compared to regular activated sludge reactors (without any carriers). The studied parameters are COD, DO, MLSS, and P-PO43-. Input COD was changed at concentrations of 1200 and 400 mg/L, and the reactor hydraulic time was adjusted to 10 and 16 hours. It was observed that...
Investigating the Reduction of Sewage Sludge Volume in Kish slandRefineries with the Help of Mud Eating Worms
, M.Sc. Thesis Sharif University of Technology ; Hashemian, Jamal (Supervisor)
Abstract
A major environmental challenge for wastewater treatment in Iran and other countries is the disposal of excess sludge produced during the biological process. This project has been developing and testing a technology that will help to overcome this challenge in Kish Island wastewater plant. Results demonstrate it can perform highly effective treatment of municipal wastewater while producing low levels of sludge.Applicationofvermifiltrationfor treatment of wastewater sludge using the Eiseniafetida earthworm species. The earthworms’ gut acted as a biofilter whereby there was reduction in the sewage wastewater’s solid and liquid organic and inorganic wastes through ingestion and expelling these...
Investigation of Highly Concentrated Phenolic Wastewater Treatment in a Membrane Biological Reactor (MBR), and Evaluation of Furfural upon Phenol Biodegradation by an Acclimated Activated Sludge
, M.Sc. Thesis Sharif University of Technology ; Borghei, Mehdi (Supervisor)
Abstract
Phenolic compounds are hazardous pollutants that are released into environment through wastewater discharges from variety of industries. Although good biodegradability has been reported at low concentrations, but at higher concentrations phenols are known to be antibacterial. In this study the Membrane Biological Reactor (MBR) with submerged hallow fiber membrane was operated at 25±2 ºC and pH=7.5±0.5 to treat a synthetic wastewater containing high phenol concentration (up to 5.9 g/l). Removal efficiency of phenol and COD were evaluated at four various “Hydraulic Retention Times” (HRT) of 24, 12, 8 and 4 hours. To test the tolerance of the bioreactor to phenol concentration various loading...
Selection of wastewater treatment process based on the analytical hierarchy process and fuzzy analytical hierarchy process methods
, Article International Journal of Environmental Science and Technology ; Volume 8, Issue 2 , March , 2011 , Pages 267-280 ; 17351472 (ISSN) ; Mehrdadi, N ; Hashemian, S. J ; Nabi Bidhendi, G. R ; Tavakkoli Moghaddam, R ; Sharif University of Technology
2011
Abstract
This paper presents an application of the analytical hierarchy process and fuzzy analytical hierarchy process methods for selecting the best wastewater treatment process. The analytical hierarchy process is one of the best ways for deciding among the complex criteria structure in different levels, and the fuzzy analytical hierarchy process is a synthetic extension of the classical method when the fuzziness of the decision makers are considered. After reviewing aerobic treatment processes operated in Iran's industrial estates and determining the main criteria used for treatment process evaluation, they are arranged in a hierarchy structure. Selection of the best wastewater treatment process...
Biological removal of nutrients (N & P) from urban wastewater with a modified integrated fixed-film activated sludge-oxic settling anoxic system using an anoxic sludge holding tank
, Article Water and Environment Journal ; Volume 35, Issue 2 , 2021 , Pages 830-846 ; 17476585 (ISSN) ; Takdastan, A ; Borghei, S. M ; Sharif University of Technology
John Wiley and Sons Inc
2021
Abstract
In this research, the efficiency of the integrated fixed-film activated sludge-oxic settling anoxic (IFAS-OSA) system in biological nutrient removal was studied. The oxic-settling anoxic (OSA) process is known as a cost effective way to reduce the nutrients (nitrogen and Phosphorus). According to the results, the percentages of total nitrogen removal efficiency in the IFAS, IFAS-OSA2h and IFAS-OSA4h systems were 78.56 ± 2.46, 83.60 ± 0.92 and 85.03 ± 1.69, respectively, while the percentages of phosphorus removal efficiency in these systems were 32.69 ± 8.25, 36.35 ± 6.73 and 39.87 ± 3.61, respectively. The PCR-RFLP method showed that C. albicans had the greatest prevalence (n = 36, 90%)....
Experimental Study of Oily Wastewater Treatment by Hybrid Baffled Bioreactor
, M.Sc. Thesis Sharif University of Technology ; Alemzadeh, Iran (Supervisor) ; Vosoughi, Manochehr (Supervisor)
Abstract
Oil refineries, petrochemical factories and oil platforms produce a large amount of oily wastewater every day. If these wastewaters are released in environment, it can damage soil and water seriously. Although, Biological treatment of oily wastewaters is a well-established method for remediation of these wastes, efficiency of conventional systems such as Activated Sludge, aren’t very high. Also these systems have many problems such as instability during hydraulics shocks and bulking phenomena. the hybrid bioreactor system are designed to increase the efficiency of treatment by allowing greater organic loads, increasing microbial concentration by using attached and suspended bacteria, and...
Chemical and Biological Phosphate Removal with a Fixed Bed Reactors Under Low Organic Load
, M.Sc. Thesis Sharif University of Technology ; Borgheei, Mahdi (Supervisor)
Abstract
Eutrophication and algae growth is one of the consequences of high concentration of nutrients in surface water bodies; therefore, both phosphorus and nitrogen existing in wastewater or at least one of them should be decreased to a standard amount before entering water to rivers. This can prevent eutrophication and detriment to the ecosystem of rivers. An investigation on both biological and chemical phosphorus and carbon removal in low loading rate influent ( below 100) has been carried out in this research. Investigated topics includes aerobic COD removal in IFAS reactor, comparison of biological nutrient removal to the combination of chemical and biological method, effect of the order of...
Effect of pH on aerobic granulation and treatment performance in sequencing batch reactors
, Article Chemical Engineering and Technology ; Volume 38, Issue 5 , 2015 , Pages 851-858 ; 09307516 (ISSN) ; Shayegan, J ; Jalali, S ; Sharif University of Technology
Wiley-VCH Verlag
2015
Abstract
Two sequencing batch reactors were operated to investigate the effect of influent alkalinity and reactor pH on aerobic granulation. In the first reactor R1 with high influent alkalinity the pH was adjusted in the neutral range, and in the second reactor R2 with low alkalinity the pH was held within the acidic range. The R1-dominating species were bacteria and the appearance time of granules was three weeks after reactor start-up. On the other hand, the acidic environment of R2 provided favorable conditions for fungal growth, and rapid granule formation occurred within the first week of operation. The varying microbial structure of granules resulted in different reactor performance in terms...
Optimization of ultrasonic waves application in municipal wastewater sludge treatment using response surface method
, Article Journal of Cleaner Production ; Volume 150 , 2017 , Pages 361-370 ; 09596526 (ISSN) ; Abedini, R ; Rajabi, R ; Sharif University of Technology
Abstract
Today, many limitations are faced in sludge treatment and disposal. Therefore evaluation of different approaches to reduce sludge production in the activated sludge process has attracted great attention. Application of ultrasonic waves in sludge treatment caused to reduce sludge volume and accelerate sludge digestion. This research intended to study the efficiency of ultrasound in dewatering biological sludge in wastewater treatment plants under different conditions. In this study, response surface method was used to investigate results and optimum conditions were determined. Sludge was treated in different conditions as follows: 330–920 W ultrasound power, 1.5–3.9 L sample volume and...
Fouling control mechanism by optimum ozone addition in submerged membrane bioreactors treating synthetic wastewater
, Article Journal of Environmental Chemical Engineering ; Volume 6, Issue 6 , 2018 , Pages 7294-7301 ; 22133437 (ISSN) ; Hazrati, H ; Shayegan, J ; Sharif University of Technology
Abstract
In this paper, the effect of ozone on membrane fouling of membrane bioreactor (MBR) systems was investigated. Sludge specification such as soluble microbial product (SMP), extracellular polymeric substance (EPS), viscosity, particle size distribution (PSD), microscopic observations and sludge volume index (SVI) in presence of ozone were determined. Further, EPS, Fourier-transform infrared (FTIR) analysis, excitation-emission matrix (EEM) fluorescence spectroscopy, and gel permission chromatography (GPC) are considered to determine cake layer characteristics. The results indicated COD removal did not show significant difference with ozonation. Ozone also increases the particle size and...
Enhancement of biological nitrogen removal performance using novel carriers based on the recycling of waste materials
, Article Water Research ; Volume 170 , March , 2020 ; Borghei, S. M ; Raie, M ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
This study aims to enhance biological nitrogen removal performance by the innovative carbon-based carriers. The new carriers were produced based on recycling waste materials. In these carriers, the advantages of the hybrid system and physicochemical properties of activated carbon were integrated to promote microbial attachment. To verify the performance of the new carriers compared to the conventional moving carriers, the experiments were conducted in two parallel laboratory-scale sequencing batch reactors under various operating conditions. The analysis revealed that the specific surface area of the new carrier with a total pore volume of 0.0015cm3/gr was 10.9 times the specific surface...
Comparative assessment of sewage sludge disposal alternatives in Mashhad: a life cycle perspective
, Article Environmental Science and Pollution Research ; Volume 27, Issue 1 , 2020 , Pages 315-333 ; Tafazzoli, S. M ; Aminian, S. T ; Avami, A ; Sharif University of Technology
Springer
2020
Abstract
Municipal wastewater treatment facilities produce a lot of sludge which is concentrated with different pollutants. The sustainable design of the sludge disposal alternatives is of crucial importance for touristic cities like Mashhad in Iran. Increasing sludge generation and its accumulation in the city and more stringent legislations highlight the challenge of sludge disposal, recently. This study compares different alternatives to reach maximum possible environmental benefits as well as the most cost-effective technologies. In this study, life cycle analysis (LCA) assesses different scenarios for disposal of sewage sludge which is aerobically treated and dewatered for two real case studies....
Wastewater treatment technology selection using a hybrid multicriteria decision-making method
, Article International Transactions in Operational Research ; 2021 ; 09696016 (ISSN) ; Kheybari, S ; Ishizaka, A ; Farazmand, H ; Sharif University of Technology
Blackwell Publishing Ltd
2021
Abstract
Various technological methods are available for industrial wastewater treatment (WWT), ranging from conventional to advanced treatment processes. It is therefore a complex exercise to select the most appropriate technology to treat the industrial wastewater in a particular situation. Many criteria can be considered in the decision-making process; therefore, multicriteria decision-making methods are especially appropriate for solving this problem. In this paper, we aim to select the most appropriate municipal WWT technology for agricultural usages. We propose a new hybrid methodology based on the best–worst method (BWM) and the behavioral technique for order of preference by similarity to the...
Management Treatment of MDF Effluent by Soil Aquifer Treatment (SAT)
, M.Sc. Thesis Sharif University of Technology ; Oskoee, Mohammad Mahdi (Supervisor) ; Jamali, Sirous (Co-Advisor)
Abstract
This study deals with the treatment of medium density fiberboard (MDF) effluent aiming at the removal of TSS, COD, BOD and Turbidity by means of soil aquifer treatment (SAT). Removal of parameters were evaluated during transport of MDF effluent under unsaturated flow conditions in 1-m soil (sandy-clay soil) depth. The experimental results showed that the new process with SAT to be very effective. The TSS, COD, BOD and turbidity removal average was about 99%, 30%, 89 and 98.5% at the optimum operation condition, respectively. The SAT should be added before the UASB in order to achieve high removal rate of COD and BOD. The UASB (concentration sludge 40000 mg/l) after SAT treatment MDF...
Experimental investigation of oily water treatment by membrane bioreactor
, Article Desalination ; Volume 250, Issue 2 , 2010 , Pages 598-600 ; 00119164 (ISSN) ; Mowla, D ; Vossoughi, M ; Hesampour, M ; Sharif University of Technology
Abstract
In this study a membrane bioreactor (MBR) has been studied experimentally for the treatment of oil field wastewater (produced water). This type of wastewater is characterised with relativity moderate to high amount of salt and oil. The normal bacteria which are growing in conventional activated sludge and MBR cannot withstand at these adverse conditions, therefore it is necessary to be adapted. In this study, different samples from sea sediment in Bushehr (south of Iran) were analysed and different groups of bacteria were isolated and adapted for surveying under high salinity conditions. The performance and efficiency of these bacteria in the degradation of model oil has been studied. The...
A new flat sheet membrane bioreactor hybrid system for advanced treatment of effluent, reverse osmosis pretreatment and fouling mitigation
, Article Bioresource Technology ; Volume 192 , 2015 , Pages 177-184 ; 09608524 (ISSN) ; Bidhendi, G. N ; Torabian, A ; Mehrdadi, N ; Pourabdullah, M ; Sharif University of Technology
Abstract
This paper introduces a new hybrid electro membrane bioreactor (HEMBR) for reverse osmosis (RO) pretreatment and advanced treatment of effluent by simultaneously integrating electrical coagulation (EC) with a membrane bioreactor (MBR) and its performance was compared with conventional MBR. Experimental results and their statistical analysis showed removal efficiency for suspended solids (SS) of almost 100% for both reactors. HEMBR removal of chemical oxygen demand (COD) improved by 4% and membrane fouling was alleviated according to transmembrane pressure (TMP). The average silt density index (SDI) of HEMBR permeate samples was slightly better indicating less RO membrane fouling. Moreover,...