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CONTENTS
Volume 3, Number 1, January 2012
 

Abstract
The coupling of anaerobic biological process and membrane separation could provide excellent suspended solids removal and better biomass retention for wastewater treatment. This coupling improves the biological treatment process while allowing for the recovery of energy through biogas. This review gives a basic description of the anaerobic wastewater treatment process, summarizes the state of the art of anaerobic membrane bioreactors (AnMBRs), and describes the current research trends and needs for the development of AnMBRs. The research interest on AnMBR has grown over the conventional anaerobic processes such as upflow anaerobic sludge blanket (UASB). Studies on AnMBRs have developed different reactor configurations to enhance performances. The AnMBR performances have achieved comparable status to other high rate anaerobic reactors. AnMBR is highly suitable for application with thermophilic anaerobic process to enhance performances. Studies indicate that the applications of AnMBR are not only limited to the high strength industrial wastewater treatment, but also for the municipal wastewater treatment. In recent years, there is a significant progress in the membrane fouling studies, which is a major concern in AnMBR application.

Key Words
anaerobic membrane bioreactor; wastewater treatment; research development; membrane fouling; high rate; thermophilic process

Address
Environmental Engineering and Management Program, School of Environment, Resources and Development, Asian Institute of Technology, Thailand

Abstract
Carboxylated polysulfone (CPS), poly (1,4-phenylene ether ethersulfone) (PPEES), membranes were prepared and used for the separation of NaCl and CaCl2, in efficient way with less energy consumption. In this work, nanofiltration and reverse osmosis membranes were employed to the salt rejection behavior of the different salt solutions. The influence of applied pressure (1-12 bar), on the membrane performance was assessed. In CM series of membranes, CM1 showed maximum of 97% water uptake and 36% water swelling, whereas, CM4 showed 75% water uptake and 28% water swelling. In RCM series, RCM1 showed 85% water uptake and 32% water swelling whereas, in RCM4 it was 68% for water uptake and 20% for water swelling. Conclusively reverse osmosis membranes gave better rejection whereas nanofiltration membrane showed enhanced flux. CM1 showed 58% of rejection with 12 L/(m2 h) flux and RCM1 showed 55% of rejection with 15 L/(m2 h) flux for 0.1 wt.% NaCl solution. Whereas, in 0.1 wt.% CaCl2 solution, membrane CM1 showed 78% of rejection with 12 L/(m2 h) flux and RCM1 showed 63% rejection with flux of 9 L/(m2 h).

Key Words
carboxylated polysulfone; NF; RO; synthesis; rejection

Address
Chitrakar Hegde : Department of Chemistry, Nitte Meenakshi Institute of Technology, Yelahanka, Bangalore-64, India
Arun M Isloor, Mahesh Padaki : Membrane Technology Division, Department of Chemistry, National Institute of Technology-Karnataka, Surathkal, Mangalore 575 025, India
Ahmad Fauzi Ismail and Lau W.J : Advanced Membrane Science & Technology Centre (AMTEC), Universiti Teknologi Malaysia,
81310 UTM, Skudai, Johor, Malaysia

Abstract
In membrane processes, various agents are used to enhance, protect, and recover membrane performance. Applying these agents in membrane modification could potentially be considered as a simple method to improve membrane performance without additional process. Citric acid (CI) and sodium bisulfite (SB) are two chemicals that are widely used in membrane feed water pretreatment and cleaning processes. In this work, preadsorptions of CI and SB were developed as simple methods for polysulfone ultrafiltration membrane modification. It was found that hydrogen bonding and Van Der Waals attraction could be responsible for the adsorptions of CI and SB onto membranes, respectively. After modification with CI or SB, the membrane surfaces became more hydrophilic. Membrane permeability improved when modified by SB while decreased a little when modified by CI. The modified membranes had an increase in PEG and BSA rejections and better antifouling properties with higher flux recovery ratios during filtration of a complex pharmaceutical wastewater. Moreover, membrane chlorine tolerance was elevated after modification with either agent, as shown by the mechanical property measurements.

Key Words
ultrafiltration; modification; citric acid; sodium bisulfite; membrane property

Address
Chemical Engineering Research Center, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, PR China

Abstract
The permeate flux declination along an ultrafilter membrane is due mainly to the concentrationpolarization resistance increment and the decline in transmembrane pressure. It was found in previous works that the concentration polarization resistance could be reduced in a ring-rod tubular membrane ultrafilter using the turbulent behavior. In the present study, the performance was further improved by properly and gradually decreasing the baffled-ring distance along the cross-flow channel coupled with properly adjusting the number of baffled rings. This theoretical analysis is based on the mass and momentum balances as well as the application of the resistance-in-series model. The correlation predictions are confirmed with the experimental results for dextran T500 aqueous solution ultrafiltration.

Key Words
ultrafiltration; tubular membrane; ring-rod insert; baffled-ring distance; proper ring number

Address
Energy and Opto-Electronic Materials Research Center,Department of Chemical and Materials Engineering,
Tamkang University, Tamsui, Taipei County251, Taiwan

Abstract
The permeate flux declination along an ultrafilter membrane is due mainly to the concentrationpolarization resistance increment and the decline in transmembrane pressure. It was found in previous works that the concentration polarization resistance could be reduced in a ring-rod tubular membrane ultrafilter using the turbulent behavior. In the present study, the performance was further improved by properly and gradually decreasing the baffled-ring distance along the cross-flow channel coupled with properly adjusting the number of baffled rings. This theoretical analysis is based on the mass and momentum balances as well as the application of the resistance-in-series model. The correlation predictions are confirmed with the experimental results for dextran T500 aqueous solution ultrafiltration.

Key Words
ultrafiltration; tubular membrane; ring-rod insert; baffled-ring distance; proper ring number

Address
Yoshinobu Tanaka : IEM Research. 1-46-3 Kamiya, Ushiki-shi, Ibaraki 300-1216, Japan
Hazime Uchino : Tokai University, College of Marine Science and Technology, 3-20-1 Orido, Shimizu-ku, Shizuoka-shi,
Shizuoka 424-8610, Japan
Masayoshi Murakami : Japan Fine Salt Co. Ltd., 3-3-3 Yako, Kawasaki-ku, Kawasaki-shi, Kanagawa 210-0863, Japan


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