Membrane Separation Technology

Membrane bioreactor (MBR) is a reliable and promising technology for wastewater treatment and reclamation applications. In spite of more than a decade of significant advances in developing fouling mitigation methods, different physical and cleaning protocols are still necessary to be developed to limit the membrane fouling. The use of scouring agents in MBR applications has been paid attention as a new approach as an energy-efficient way to control membrane fouling. Recently, mechanical cleaning by scouring agents is becoming as intense research area considering high efficiency of fouling reduction while requiring low energy consumption. In this review, fundamental and comprehensive assessments of the mechanical cleaning concepts and their applications with porous and nonporous scouring agents for MBR system are critically reviewed. The existing challenges and future research prospects on the mechanical cleaning technology associated with scouring agents for the MBR applications are also discussed.

Membran Nata de Banana skin digunakan sebagai membran mikrofiltrasi. Pada praktikum kali ini membran digunakan untuk proses filtrasi larutan tepung tapioka dan tepung terigu. Driving force yang digunakan berupa tekanan. Tekanan tersebut dihasilkan dari pompa vakum.

Banana is a much appreciated tropical fruit due to its unique
aroma, flavor, and also for its nutritional and energetic components.
In this work, banana juice was extracted by pectinase treatment at
room temperature. The resultant juice was clarified by two methods,
namely, centrifugation and microfiltration. A comparative study
was performed between these two primary clarification methods.
Response surface methodology was used to optimize the parameters
of centrifugation (speed and time) as well as microfiltration
(transmembrane pressure and cross flow rate). The juice was
characterized in terms of viscosity, clarity, alcohol insoluble solids
(AIS), polyphenol, and protein content. Centrifuged juice contained
high concentration of total polyphenol and protein. Juice obtained
from microfiltration had lower viscosity, AIS, and higher clarity.
Also, the energy consumption of the centrifuge is much higher
than that of microfiltration.

Heterogeneous photocatalysis is a promising technology especially for environmental remediation. Despite more than a decade of worldwide research in developing photocatalytic efficiency improving techniques, many questions regarding the large scale application of photocatalytic reactors still remain unanswered. Recently, improving the photocatalytic efficiency has gained scientific attention because it might lead to more economical and robust photocatalytic operation for environmental remediation. In this review, fundamental and comprehensive assessments of the photocatalytic concepts and their applications for environmental remediation are reviewed. The existing challenges and strategies to improve the photocatalytic efficiency are discussed. Further, recent developments and future research prospects on photocatalytic systems for environmental applications are also addressed.

To meet the worldwide rapid growth of industrialization
and population, the demand for the production
of bioethanol as an alternative green biofuel is gaining significant
prominence. The bioethanol production process
is still considered one of the largest energy-consuming
processes and is challenging due to the limited effectiveness
of conventional pretreatment processes, saccharification
processes, and extreme use of electricity in common
fermentation and purification processes. Thus, it became
necessary to improve the bioethanol production process
through reduced energy requirements. Membrane-based
separation technologies have already gained attention
due to their reduced energy requirements, investment in
lower labor costs, lower space requirements, and wide
flexibility in operations. For the selective conversion of
biomasses to bioethanol, membrane bioreactors are specifically
well suited. Advanced membrane-integrated
processes can effectively contribute to different stages of
bioethanol production processes, including enzymatic
saccharification, concentrating feed solutions for fermentation,
improving pretreatment processes, and finally
purification processes. Advanced membrane-integrated
simultaneous saccharification, filtration, and fermentation
strategies consisting of ultrafiltration-based enzyme
recycle system with nanofiltration-based high-density cell
recycle fermentation system or the combination of highdensity
cell recycle fermentation system with membrane
pervaporation or distillation can definitely contribute to
the development of the most efficient and economically
sustainable second-generation bioethanol production
process.

Tenaga pendorong, jenis membran yang dipakai, dan contoh aplikasinya di bidang teknik biosistem dari berbagai jenis proses membran (mikrofiltrasi, ultrafiltrasi, reverse osmosis, forward osmosis, reaktor membran, pervaporasi, dialisis, elektrodialisis, membran kontaktor, membran destilasi, membran liquid)

For supplying drinking water throughout the world, there has been a huge growth in the usage of desalination factories. Nevertheless, the formation of brine (concentrate) is a complete side of the working of the desalination factory and encounters serious ecological defiance due to its elevated salinity. Thus, a cost-effective and environmentally friendly concentrate handling equipment is needed before its appropriate elimination. Presently, many elimination choices comprising surface water discharge, deep well injection, and evaporation ponds have been employed. Nevertheless, such methods are unsustainable and their application is restricted by an elevated capital cost and exclusive usages. Different traditional techniques comprising physicochemical, oxidation and biological methods with changing degrees of organics elimination have been noted. These days, membrane-based techniques seem to be cost-effective tools for treating brine since they could recuperate worthy resources and generate clean water with elevated recuperation. This review contributes to discussing the actual techniques for brine handling, comprising elimination usages and treatment methods. The features of the concentrate in a matter of water nature and its effect on open water bodies are reviewed. This work presents emerging membrane processes like forward osmosis, membrane distillation, and electrodialysis that are encouraging for reducing brine quantities, in recuperating worthy metals and enhancement of water recuperation. This discussion as well focuses on the reality that integrated membrane processes are better for concentrate handling for metals recuperation jointly with water decontamination in wastewater treatment factories and could attain a zero liquid discharge.

The main objective of this study is to investigate the thermal profiles of a trailer-scale gasifier in different
zones during the course of gasification and also to elaborate on the design, characteristics and performance
of the gasification system using different biomass feedstock. The purpose is to emphasize on
the effectiveness of distributed power generation systems and demonstrate the feasibility of such gasification
systems in real world scenarios, where the lingo-cellulosic biomass resources are widely available
and distributed across the board. Experimental data on the thermal profiles with respect to five different
zones in the gasifier and a comprehensive thermal–chemical equilibrium model to predict the syngas
composition are presented in detail. Four different feedstock-pine wood, horse manure, red oak, and
cardboard were evaluated. The effects of C, H, O content variations in the feedstock on the thermal profiles,
and the efficiency and viability of the trailer-scale gasifier are also discussed.

Membrane distillation (MD) is a developing thermally driven membrane desalination technology that has been applied in four different basic configurations. In membrane distillation, a hot, saline feed stream is passed over a hydrophobic membrane. The temperature difference between the two sides of the membrane leads to a vapour pressure difference that causes water vapour to permeate through the membrane pores, and then condensed on the cold side of the membrane. The hydrophobicity of the membrane prevents the liquid from passing through the pores, while the water vapour is allowed to pass through. The technique offers the attractiveness of operation at atmospheric pressure and low temperature (40– 90oC), and has the theoretical ability to achieve 100% salt rejection. Thus, low-grade energy like solar and waste energy can be used for desalination.
In this work, an experimental investigation of the performance of Air Gap Membrane Distillation (AGMD) system was performed for seawater and laboratory prepared salt feed water solutions. The influences of  system operating parameters such as feed temperature, feed flow rate, coolant temperature, coolant flow rate and air gap width on permeate flux were studied. The effects of membrane pore size as well as the concentration of feed solution on permeate flux were also investigated. The performance of the AGMD unit was statistically optimized using design of experiment (DOE) and Taguchi technique. Furthermore, theoretical model describing heat and mass transfer analysis in AGMD was developed and discussed in detail.
The permeate flux was found to increase with increasing feed temperature and feed flow rate. However, it decreased with increasing air gap width and coolant temperature. The system performance tends to increase marginally with increasing coolant flow rate. The system performance is mostly dominated by the effect of both feed temperature and air gap width. Feed flow rate and coolant temperature have relatively considerable effect on flux. Increasing the membrane pore size from PTFE 0.22µm to PTFE 0.45µm leads to about 10% increment in flux production. While increasing the feed concentration from 0.075g/L to 60g/L lead to about 11% drop in permeate flux. The tested double-stage AGMD design was capable of achieving a maximum permeate flux of 128.46kg/m2hr, which is almost twice that of single stage unit, under the same experimental conditions.
In general, the theoretical model results were found to be in good agreement with the experimental data as the maximum deviation of model results was within 15%. The model was also used to predict thermal efficiency and temperature polarization of the AGMD system.
Regarding system optimization using Taguchi methodology, the developed model proved to be in good agreement with the experimental data with a maximum deviation of about 10%. According to Taguchi orthogonal arrays, the experimental and model optimum system performance was found to be 76.0457 kg/m2h, and 74.5916 kg/m2h respectively. The conditions for the optimum performance are 80oC feed temperature, 5 L/min feed flow rate, air gap width of 3mm and coolant temperature of 20oC.

• GO nanosheets were successfully embedded in PA layer via filtration IP technique. • GO nanosheets increased membrane surface hydrophilicity and provided nanochannels for higher permeability. • TFN-f 0.02 showed optimum PWP which was 31.4% higher than the control membrane. • TFN-f 0.02 showed 95.8% and 97.7% rejection against Na 2 SO 4 and MgSO 4 , respectively. A B S T R A C T In this work, tailor-made graphene oxide (GO) incorporated thin film nanocomposite (TFN) membranes based on novel interfacial polymerization (IP) technique were presented. The embedment of GO nanosheets within ul-trathin cross-linked polyamide (PA) layer was successfully achieved without forming particle agglomeration that could affect structural integrity. A total of five composite membranes with different GO loadings (0, 0.01, 0.02, 0.03 and 0.04 g/m 2) were fabricated and these membranes were characterized using TEM, FESEM, XPS, ATR-FTIR and contact angle goniometer to evaluate the impact of GO loading on the physicochemical properties of PA selective layer. It is found that with the presence of GO, the TFN membranes exhibited higher surface hy-drophilicity due to increment in hydroxyl and carboxyl groups in PA layer, hence, improved the attraction between water molecules and membrane surface. Upon incorporation of 0.02 g/m 2 of GO, the resultant TFN membrane achieved 95.8% and 97.7% removal rate for Na 2 SO 4 and MgSO 4 , respectively along with 31.4% higher water flux than the membrane contained no GO. More importantly, this work demonstrated the broad

A hybrid reactive distillation system with high selectivity pervaporation was examined to produce butyl acetate and methanol via transesterification of methyl acetate with butanol. High selectivity pervaporation was combined with reactive distillation to eliminate a hitherto required column for the separation of a methanol and methyl acetate azeotrope. The polyamide-6 membrane was used for this purpose because of its high selectivity for methanol while also allowing sufficient permeate flux. The high purity methyl acetate recovered in the retentate stream leads to high conversion in the reactive distillation column, which enhances the energy savings (up to 71%) of this process. The feasibility of the proposed hybrid processes and several alternative designs were evaluated by rigorous simulation and optimization using the Aspen Plus software package. The effects of several designs and operating variables were also investigated for the proposed design. The high potential of the hybrid reactive distillation and pervaporation system for butyl acetate production is very promising; it may not only reduce the total annual costs relative to conventional systems but may also provide an attractive strategy to address problems associated with methanol and methyl acetate azeotropes in the effluent generated in the polyvinyl alcohol industry.

Gac (Momordica cochinchinensis Spreng.) fruit, a traditional fruit in Vietnam and other countries of eastern Asia, contains an oil rich in carotenoids, especially lycopene and β-carotene. Carotenoids in gac fruit oil were concentrated using cross-flow filtration. In total recycle mode, effect of membrane pore size, temperature, and transmembrane pressure (TMP) on permeate flux and on retention coefficients has been exploited. Resistance of membrane, polarization concentration, and fouling were also analyzed. Optimum conditions for a high permeate flux and a good carotenoids retention are 5 nm, 2 bars, and 40 °C of membrane pore size, TMP, and temperature, respectively. In batch mode, retentate was analyzed through index of acid, phospholipids, total carotenoids content (TCC), total antioxidant activity, total soluble solids, total solid content, color measurement, and viscosity. TCC in retentate is higher 8.6 times than that in feeding oil. Lipophilic antioxidant activities increase 6.8 times, while hydrophilic antioxidant activities reduce 40%. The major part of total resistance is due to polarization (55%) while fouling and intrinsic membrane contribute about 30% and 24%, respectively.

Utilization of an integrated forward osmosis-solar powered membrane distillation system can provide a promising method for brackish water desalination. In this study, the brackish water feed and fertilizer draw solutions were operated in a forward osmosis process to generate irrigation water for agriculture. Forward osmosis was also selected as membrane distillation pre-treatment to avoid fouling and wetting of the membrane distillation membrane. Subsequently, the diluted draw solutions were treated in the membrane distillation system to recover the initial osmotic pressure and to obtain a final distillate permeate. The experimental results revealed that the modified forward osmosis membrane exhibited slightly better performance in terms of maximum water flux, minimum reverse solute flux and high water recovery of 53.5%. In the membrane distillation process, an optimum water flux of about 5.7 L/m2.hr and high rejection rate of about 99.55% were achieved at an optimum temperature of 60 °C. Modelling was applied to investigate the feasibility of using a solar collector to power the membrane distillation system and hence limit energy costs. By using renewable energy, we calculate that the energy consumption of the hybrid system could be reduced by 67%. Membrane distillation-solar powered system can achieve optimum energy consumption recorded as 1.1 kWh. We concluded that the diluted fertilizer draw solution can be used as an irrigation water after further dilution by an available water source. By using forward osmosis prior to membrane distillation process, the membrane distillation membrane showed less fouling and
wetting leading to excellent rejection rate and acceptable distillate permeate. The energy consumption of the forward osmosis-solar powered membrane distillation system was lower than that for reverse osmosis standalone system. The findings of this work could be used to develop guidelines for the optimal design of industrial forward osmosis-membrane distillation system.

This paper presents a novel hybrid process combining thermally coupled reactive distillation with membrane-based pervaporation for enhanced production of n-butyl acetate. A conventional reactive distillation process was used as the base case and first optimized for the transesterification of methyl acetate with n-butanol to produce n-butyl acetate. It was observed that methyl acetate recovered in the recycle stream significantly affects the con-version in the reactive distillation column and overall energy efficiency of the whole process. The existing and proposed configurations were evaluated and optimized by simulation in Aspen Plus. The integration of thermally coupled reactive distillation and pervaporation improved the energy efficiency of the reactive distillation process by preventing remixing effect in the reactive distillation column and eliminating the azeotropic nature of the methanol and methyl acetate in the recycle stream, respectively. Finally, integration of the thermally coupled reactive distillation with a commercial pervaporation membrane was explored to take synergistic advantage of the thermally coupled reactive distillation and pervaporation hybrid configuration. As a result, the proposed hybrid design showed remark-ably improved energy efficiency and economics. The total reboiler duty and total annual cost reduced to 63 and 43%, respectively, compared to those of the base case.

Mixed matrix membranes (MMMs) are a promising alternative to conventional polymeric membranes but suffer from compatibility issues of polymer and filler. This study reports simultaneous improvement in CO2 perme-ability and selectivity employing novel metal organic frameworks (MOFs), namely NOTT-300 and Pebax®1657 as polymer matrix. MMMs are characterized and investigated for separation of CO2 /CH 4 and CO 2 /N 2 gas mixtures at ambient and elevated temperatures. Well-dispersed NOTT-300 particles are observed in SEM images of MMMs with no visible defects even at higher loadings. Single and mixed gas permeation results showed their outstanding performance exhibiting a simultaneous upsurge in CO 2 permeability and CO2 /CH 4 and CO2 /N 2 selectivity. In comparison to neat Pebax®1657 membrane, the incorporation of NOTT-300 at 40% filler loading enhanced the permeability of CO2 by 380%, and selectivity to 68% and 26% for CO2 /CH 4 and CO2 /N 2 respectively. The results proved the potential of NOTT-300 as filler material for MMMs aimed at CO2 capture because of their high porosity and CO2 philic properties.

This research focuses on vacuum membrane distillation (VMD) using high-concentration NaCl aqueous
solutions as feed. A new membrane module was investigated to improve water desalination and experiments
were carried out using a commercial polypropylene (PP) membrane with a pore size of 0.2m. In
order to enhance performance of VMD in desalination and to get more flux, effects of operating parameters
on the performance were studied. Water fluxes were measured at different feed temperatures, feed
concentrations, vacuum pressures and flow rates. The new configuration provides better mixing and this
increases heat and mass transfer coefficients, and as a result, reduces temperature and concentration
polarization effects.

In recent years the climate change became a global concern due to the increasing of the earth’s surface temperature. This phenomenon was exacerbated by the expansion of industrial activities due to the increasing emissions of the greenhouse gas (mainly CO2). Many efforts were conducted to capture CO2 from the industrial process streams. Membrane gas absorption system (MGAS) was proposed as an alternative technique to overcome disadvantages of the conventional CO2 absorption processes. However, there are still many challenges in order to commercialize MGAS such as membrane surface stability, absorbent liquid efficiency and compatibility between absorbent liquid and membrane material. In order to solve this problem, a porous superhydrophobic layer of low density polyethylene (LDPE) had been coated on the outer surface of the polypropylene (PP) and polyvinylidene fluoride (PVDF) hollow fiber membrane via solvent non-solvent coating method. Parameters to prepare superhydrophobic flat surface (non-solvent type, non-solvent content in coating solution and polymer concentration) had been studied and optimized. It was observed that non-solvent like ethanol did produce polymeric surface with higher water contact angle (WCA) compared to methyl ethyl ketone used as non-solvent additives. The increasing of ethanol content in the coating solution up to 50% (v/v) led to the increased of WCA from 110±2.8o to 160±1.4o. The hydrophobicity of the coated layers were analysed in terms of surface roughness, physical structure and water contact angle. It was found that the WCA of the coated PP and PVDF hollow fiber membranes surfaces prepared via direct dip coating were less than the flat surface. Indirect method was proposed and the maximum WCA of modified PP and PVDF membranes were 161±2.3o and 152±3.2o, respectively. A continuous MGAS inhouse-built was designed to evaluate the performance of modified membranes in term of CO2 removal from gas stream of 20% (v/v) CO2 balanced with N2. The operating parameters (liquid velocity, gas velocity and packing density of the membrane module) and other effects on the CO2 removal were studied. The CO2 absorption performance was investigated for different absorbent liquids namely piperazine (PZ), monoethanolamine (MEA), diethanolamine (DEA) and their blends. PZ exhibited higher absorption efficiency than other absorbents. In terms of the membrane’s compatibility with PZ, PVDF membrane was found to have high surface stability compared to the PP membrane. In addition, it was observed that the activated MEA had CO2 absorption efficiency higher than activated DEA at the same concentrations and operating conditions. The mass transfer resistance through the membrane module was determined via Wilson plot method. It was observed that the liquid mass transfer resistance was the controlling step in all amine solutions. Moreover, the overall mass transfer coefficient was increased with the increasing of the activator concentration in the amine blends.

Since the 1970s' disinfection by-products (DBPs) detection, the water treatment specialists' main focuses were accorded to the DBPs formation, characterization, regulations and control. Involved stages in disinfection process were at a certain level kept at the side as a black box. This paper is a broad review on chlorination applied in water treatment technology especially in terms of involved mechanisms. Chlorine occasions significant injury to bacterial cells, cell permeability dislocation and nucleic acids and enzymes injury. Hypochlorous acid oxidizes sulfhydryl groups, harms iron-sulfur centers, deactivates nutrient transport, hinders cell respiration, and deteriorates the capacity of cells to keep a sufficient adenylate energy charge to stay viable. All disinfectants are highly efficient killing agents. However, these chemical products are very toxic by their selves. Moreover, they interact with NOM, microorganisms, and algae to produce DBPs which are as well poisonous. Consequently, the use of disinfectants must be avoided upon using physical processes or at least reduced as possible at the lowest level.

Bu çalışmada değişken moleküler ağırlıkta ve konsantrasyonda hazırlanan polivinil butiral polimer çözeltileriyle iğneli elektro
lif çekim yöntemi kullanılarak nano lif yüzeyler elde edilmiştir. Moleküler ağırlığın ve konsantrasyonun nano lif morfolojisi
üzerindeki etkisi incelenmiştir. Moleküler ağırlığı 60.000 ve 75.000 g/mol olan PVB polimeri farklı konsantrasyonlarda
kullanılmıştır. Solüsyonun yüzey gerilimi, iletkenlik ve viskozite testleri yapılmıştır. Oluşan nano lifin SEM görüntüleri elde
edilmiş ve lif çapları hesaplanmıştır. Lif özellikleri ve materyal özellikleri arasındaki bağlantı saptanmıştır. Elde edilen
yüzeyler ve parametrelere bağlı olarak uygun polimer çözeltisine ulaşılmıştır. En uygun konsantrasyon ve moleküler ağırlık 60,000 g/mol‟de %10 ve %12 polivinil butiral çözeltisi olarak saptanmıştır.

Electrospinning is a popular method to obtain nanofibers. Polyacrylonitrile (PAN) nanofibers in the range of 50 to 750 nm were prepared by electrospinning of homogeneous viscous solutions with varied polymer concentration in 10-16% (w/v) range in N, N-Dimethylformamide (DMF). The morphology of fibers observed by Scanning Electron Microscopy (SEM) indicated that the morphology transformation from beaded fiber to cylindrical form occurred at 14%, and the average fiber diameter at this concentration is 379 ± 54 nm. The polyacrylonitrile nanofibers were characterized by the Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR). Differential Scanning Calorimeter (DSC) study of electrospun fibers revealed the presence of three thermal transitions in glass transition of PAN fibers. Membrane of 14% PAN nanofiber was subjected to vacuum for removal of air from the pores along with partial densification. This membrane was tested for bacteria reduction and found to eliminate model E. coli bacteria up to 99.9997%. In addition, membranes of different thicknesses in the range of 125 µm to 750 µm were also electrospun and flow rate of water (flux) was measured. It was found that the flux exponentially decreased with the increase in thickness due to the strong resistance to flow through nanosized pores.

This research focuses on desalination via vacuum membrane distillation (VMD). In order to enhance the
performance of VMD in desalination and to get more flux, effects of operating parameters on the yield of
distillate water were studied. Four parameters at three levels were selected: temperature (35, 45, and 55 °C),
vacuum pressure (30, 80, and 130 mbar), flow rate (15, 30, and 60 mL/s) and concentration (50, 100, and
150 g/L). Taguchi method was used to plan a minimum number of experiments. The optimal levels thus
determined for the four factors were: temperature 55 °C, vacuum pressure 30 mbar, flow rate 30 mL/s and
concentration 50 g/L. The results show that increasing temperature and decreasing vacuum pressure
improve permeate flux. However, the permeate flux increases with increasing flow rate initially and then
reaches to a maximum value at 30 mL/s and then decreases with increasing the flow rate.

Membrane Distillation (MD) is a thermally driven membrane Separation technique that is used for water desalination by separating water vapor from feed salty/brackish water using micro-porous hydrophobic membrane.
Comprehensive experimental and theoretical studies on the performance of an air gap membrane distillation (AGMD)  System are presented. The effects of main operating and design variables on the permeate flux are reported. The design of the AGMD module and the experimental setup are presented in details. PTFE membranes of two different pore sizes are characterized and tested. Results show that the system  Performance is highly affected by changes in both feed temperature and air gap width. Increasing the feed temperature from 40 °C to 80 °C increases the flux by 550% to 750%, depending on the other operating variables. A maximum of 130% rise in flux, approximately, was achieved when the air gap width was decreased from 7mm to 3mm. The maximum
permeate flux obtained from the current AGMD system is 71.1 kg/m2 hr. The measured salt rejection factor is above 99.9% that emphasizes the suitability of the AGMD system for desalination of high concentration feeds.
A theoretical model based on the analysis of heat and mass transfer is developed to predict the permeate flux and to study the system efficiency. The theoretical model is validated by comparing the permeate flux with experimentally measured values where a maximum deviation of 15% is observed. The evaporation efficiency of the AGMD module and the temperature polarization coefficient are thoroughly investigated theoretically at different operating parameters.

ÖZ Bu çalışmada, kağıt endüstrisi atıksularının NFgevşek/NFsıkı membran filtrasyonu ile sürekli işletimi sonucu oluşan konsantre akımın, hibrit İleri Oksidasyon (Fenton ve foto-Fenton)/batık UF prosesleri ile arıtılarak minimizasyonu hedeflenmiştir. MPF-36/ESNA membran filtrasyonu ile nihai çıkış suyunda 71 mg/L KOİ ve 19 mg/L TOK değerlerine ulaşılmıştır. Oluşan konsantrenin İOP/batık UF prosesleri ile arıtımında, en iyi performans UVC-batık UF prosesinde elde edilmiştir. UF çıkış suyu TOK ve KOİ değerlerinin, kullanılan ham kağıt atıksuyuna yakın değerlerde olduğu görülmüş ve NFgevşek girişine verilebileceği belirlenmiştir. Bu sayede, membran prosesler kullanılarak su geri kazanımı sağlanırken, membran konsantrelerininde hibrit proses ile minimizasyonu sonucunda konsantre yönetimine önemli katkılar sağlanabileceği görülmüştür. Anahtar Kelimeler: kağıt atıksuları, fenton ve foto-fenton prosesi, hibrit proses, konsantre yönetimi ABSTRACT This study aimed to minimize the concentration obtained after the concentrate flow resulting from continuous operation of the NFloose/NFtight membrane filtration is treated through a hybrid Advanced Oxidation (Fenton and photo-Fenton)/submerged UF processes. With the MPF-36/ESNA membrane filtration, 71 mg/L COD and 19 mg/L TOC values were obtained in the final effluent. The treatment of the resultant concentrate current with the IOP/submerged UF hybrid processes, it was observed that UVC-submerged UF process provided the best performance. TOC and COD values in the UF effluent were found to be close to the values of the raw paper wastewater used and it was determined that it could be fed to the NFloose input. Thus, while water recovery is ensured, it was also observed that the minimization of the membrane concentrate through hybrid process will achieve significant contributions to concentrate waste management.

In  this  paper,  the  capability  of  hollow-fiber  membrane  bioreactor  (HF-MBR)  for  real  petroleum  refin-
ery  wastewater  treatment  was  studied.  A  pilot  immersed  HF-MBR  was  designed,  and  the  treatment
investigated  under  various  hydraulic  retention  time  (HRT),  flux,  temperature,  and  different  operational
conditions.  The  bioreactor  included  an  ultrafiltration  membrane  (UF)  and  Arak  refinery  wastewater  used
as  the  influent  stream.  The  HF-MBR  was  running  throughout  160  days.  The  result  indicated  that  aver-
age  elimination  efficiencies  of  chemical  oxygen  demand  (COD),  biological  oxygen  demand  (BOD5),  total
suspended  solids  (TSS),  volatile  suspended  solids  (VSS)  and  turbidity  were  attained  82%,  89%,  98%,  99%,
and  98%,  respectively.  Furthermore,  the  mixed  liquor-suspended  solid  (MLSS)  and  mixed  liquor  volatile-
suspended  solids  (MLVSS)  concentration  raised  from  minimal  concentration  to  about  6.6  and  6.1  g/L,
respectively.

In this study, the capabilities of response surface methodology (RSM) and artificial neural networks (ANN) for modeling and optimization of ethanol production from glucose using Saccharomyces cerevisiae in batch fermentation process were investigated. The effects of three independent variables in a defined range of pH (4.2-5.8), temperature (20-40 °C) and glucose concentration (20-60 g/l) on the cell growth and ethanol production were evaluated. The results showed that the prediction accuracy of ANN was apparently similar to RSM. At optimum conditions of temperature (32 °C), pH (5.2) and glucose concentration (50 g/l), suggested by the statistical methods, the maximum cell dry weight and ethanol concentration obtained from RSM were 12.06 and 16.2 g/l, whereas experimental values were 12.09 and 16.53 g/l, respectively. The present study showed that using ANN as a fitness function, the maximum cell dry weight and ethanol concentration were 12.05 and 16.16 g/l, respectively. Also, the coefficients of determination for biomass and ethanol concentration obtained from RSM were 0.9965 and 0.9853 and from ANN were 0.9975 and 0.9936, respectively. The process parameters optimization was successfully conducted using RSM and ANN; however, prediction by ANN was slightly more precise than RSM. Based on experimental data, the maximum yield of ethanol production of 0.5 g ethanol/g substrate (97% of theoretical yield) was obtained.

Electrospinning is a popular method to obtain nanofibers. Polyacrylonitrile (PAN) nanofibers in the range of 50 to 750 nm were prepared by electrospinning of homogeneous viscous solutions with varied polymer concentration in 10 – 16% (w/v) range in N, NDimethylformamide (DMF). The morphology of fibers observed by Scanning Electron Microscopy (SEM) indicated that the morphology transformation from beaded fiber to cylindrical form occurred at 14%, and the average fiber diameter at this concentration is 379 ± 54 nm. The polyacrylonitrile nanofibers were characterized by the Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR). Differential Scanning Calorimeter (DSC) study of electrospun fibers revealed the presence of three thermal transitions in glass transition of PAN fibers. Membrane of 14% PAN nanofiber was subjected to vacuum for removal of air from the pores along with partial densification. This membrane was tested for bacteria reduction and found to eliminate mode...