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Volume 6, Number 4, July 2015

This paper deals with the influence of chemical oxygen demand to nitrogen ratio ((COD/N) ratio) on the performance of an membrane bioreactor. We aim at establishing relations between COD/N ratio, organisms

Key Words
membrane bioreactor; autotrophic organisms; oxygen uptake rate; autotrophic-heterotrophic ratio; fouling

(1) Aicha Gasmi, Marc Heran, Alain Grasmick:
European Membrane Institute, University of Montpellier II CC05, P.O. Box 34095, France;
(2) Aicha Gasmi, Ahmed Hannachi:
Laboratory of process engineering and Industrial systems, University of Gabes, Street Omar Ibn Elkhattab 6029, Tunisia.

The extraction of lactic acid by an emulsion liquid membrane (ELM), in batch and continuous mode, has been reported. On the basis of preliminary experiments, the optimum composition of the organic phase (membrane) is determined. When the SPan 80 is used as surfactant, the emulsion breakage exceeds 50%, but only 10% is obtained when the ECA4360 is used. The effects of surfactant, carrier and solute concentrations, phase volume ratio, and stirring speed on the extraction yield were examined and optimized. Surfactant, carrier and diluent used were ECA4360, trilaurylamine (TLA) and dodecane, respectively; 2-ethylhexane-1,3-diol (EHD) is used as a co-surfactant. Under optimal conditions, emulsion breaking is very low and the swelling is kept at its lowest level. Under the pH conditions of fermentation medium, the extraction yield is lower. A mixer-settler continuous system was used for testing these conditions. The residence time, the number of extraction stages and the stability of the emulsion were studied and optimized. The extraction yield obtained exceeds 90%.

Key Words
lactic acid; emulsion liquid membrane; continuous extraction; mixer-settler; whey effluent

(1) Tarek Berrama:
Laboratory of Industrials Processes Engineering Science, University of Sciences and Technology Houari Boumediène, PO Box 32, El-Alia, 16111, Bab-Ezzouar, Algiers, Algeria;
(2) Dominique Pareau, Gérard Durand:
Laboratory of Chemical and Process Engineering, Ecole Centrale de Paris, Grande Voie des Vignes, 95295, Chatenay Malabry Cedex France.

Palm oil mill effluent (POME) was produced in huge amounts in Malaysia, and if it discharged into the environment, it causes a serious problem regarding its high content of nutrients and high levels of COD and BOD concentrations. This study was devoted on POME treatment and purification using an integrated process consisting of microalgae treatment followed by membrane filtration. The main objective was to find the optimum conditions as retention time and pH in the biological treatment of POME. Since after the optimum conditions there is a diverse effect of time and the process become costly. According to our knowledge, there is no existing study optimized the retention time and percentage removal of nutrients for microalgae treatment of POME wastewater. In order to achieve with optimization, a second order polynomial model regression coefficients and goodness of fit results in removal percentages of ammonia nitrogen (NH3-N), orthophosphorous (PO4-3), COD, TSS, and turbidity were estimated. WinQSB technique was used to optimize the objective function of the developed model, and the optimum conditions were found. Also, ultrafiltration membrane is useful for purification of POME samples as verified by experiments.

Key Words
POME; microalgae; optimization; membrane filtration

(1) R.I. Ibrahim:
Department of Electromechanical Engineering, University of Technology, Iraq;
(2) A.W. Mohammad, Z.H. Wong:
Department of Chemical and Process Engineering, The National University of Malaysia, Malaysia.

We report in this study the synthesis of mixed matrix reverse osmosis membranes by interfacial polymerization (IP) of thin film nanocomposite (TFNC) on porous polysulfone supports (PS). This paper investigates the synthesis of ZnO nanoparticles (NPs) using the sol-gel processing technique and evaluates the performance of mixed matrix membranes reached by these aerogel NPs. Aqueous m-phenyl diamine (MPD) and organic trimesoyl chloride (TMC)-NPs mixture solutions were used in the IP process. The reaction of MPD and TMC at the interface of PS substrates resulted in the formation of the thin film composite (TFC). NPs of ZnO with a size of about 25 nm were used for the fabrication of the TFNC membranes. These membranes were characterized and evaluated in comparison with neat TFC ones. Their performances were evaluated based on the water permeability and salt rejection. Experimental results indicated that the NPs improved membrane performance under optimal concentration of NPs. By changing the content of the filler, better hydrophilicity was obtained; the contact angle was decreased from 74° to 32°. Also, the permeate water flux was increased from 26 to 49 L/m2.h when the content of NPs is 0.1 (wt.%) with the maintaining of lower salt passage of 1%.

Key Words
Nano-ZnO; interfacial polymerization; nanocomposite; nanofiltration; desalination

(1) A.S. AL-Hobaib:
Institute of Atomic Energy Research, King Abdulaziz City for Science and Technology (KACST), 11442 P.O. Box 6086 Riyadh, Saudi Arabia;
(2) Jaber El Ghoul, Lassaad El Mir:
Al Imam Mohammad Ibn Saud Islamic University (IMSIU), College of Sciences, Department of Physics, Riyadh 11623, Saudi Arabia;
(3) Jaber El Ghoul, Lassaad El Mir:
Laboratory of Physics of Materials and Nanomaterials Applied at Environment (LaPhyMNE), Gabes University, Faculty of Sciences of Gabes, 6072, Tunisia.

Membrane Fouling was considered as major drawback in various industrial applications. Thus, this paper reviews the surface modification of polyethersulfone (PES) membranes for antifouling performance. Various modification techniques clearly indicate that hydrophilicity has to improve on the PES membrane surface. Moreover, the mechanism of fouling reduction with corresponds to various modification methods is widely discussed. Incorporation of hydrophilic functional groups on PES membrane surface enhances the surface free energy thereby which reduces the fouling. Characterization techniques adopted for the surface modified membranes was also discussed. These studies might be useful for the other researchers to utilize the modification technique for the applications of waste water treatment, chemical process industry and food industry.

Key Words
surface modifications; fouling; hydrophilic modifiers; polymer additives; flux decline

(1) R. Sathish Kumar, G. Arthanareeswaran:
Membrane Research Laboratory, Department of Chemical Engineering, National Institute of Technology, Tiruchirappalli-620015, India;
(1) Diby Paul, Ji Hyang Kweon:
Department of Environmental Engineering, Konkuk University, Seoul 143-701, South Korea.

Experiments were carried out using granular activated carbon (GAC) adsorption techniques to treat wastewater contaminated with organic compounds caused by diverse human activities. Two techniques were assessed: adsorbent GAC prepared from coconut shell (GACC) and adsorbent GAC from palm shell (GACP). A comparison of these two techniques was undertaken to identify ways to improve the efficiency of the treatment process. Analysis of the processed wastewater showed that with GACC the removal efficiency of biochemical oxygen demand (BOD), chemical oxygen demand (COD), turbidity, total suspended solids (TSS) and total dissolved solids (TDS) was 65, 60, 82, 82 and 8.7%, respectively, while in the case of GACP, the removal efficiency was 55, 60, 81, 91 and 22%, respectively. It can therefore be concluded that GACC is more effective than GACP for BOD removal, while GACP is better than GACC for TSS and TDS removal. It was also found that for COD and turbidity almost the same results were achieved by the two techniques. In addition, it was observed that both GACC and GACP reduced pH value to 7.9 after 24 hrs. Moreover, the optimal time period for removal of BOD and TDS was 1 hr and 3 hrs, respectively, for both techniques.

Key Words
institutional wastewater; activated carbon; pollutants; BOD; COD

(1) Mohammed R. Khaleel, Amimul Ahsan, N.N. Nik Daud, T.A. Mohamed:
Department of Civil Engineering, and Institute of Advanced Technology, University Putra Malaysia, UPM 43400, Serdang, Selangor, Malaysia;
(2) Amimul Ahsan:
Department of Civil and Environmental Engineering, University of Sharjah, PO Box 27272, UAE;
(3) M. Imteaz:
Faculty of Engineering and Industrial Sciences, Swinburne University of Technology, Melbourne, Australia;
(4) M.M. El-Sergany:
e-School of Health and Environmental Studies, Hamdan Bin Mohamed Smart University, Dubai, UAE;
(5) Buthainah A. Ibrahim:
Physics Department, Science Faculty, Diyala University, Baquba, Iraq.

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