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The aim of the present work is the valorization of the biomass Pleurotus mutilus fungal biomass in the biosorption of metribuzin pesticide. The present study constitutes of two principal parts. The first part includes physical pretreatment and structural characterization of the biomass. In the second part, different parameters likely to have an influence on the biosorption capacity of metribuzin such as biomass, particle size, biosorbent content, agitation, temperature, pH and metribuzin concentration were studied. The results of adsorption experiments obtained for synthetic water were convincing, and an adsorption rate of metribuzin of approximately 70% was reached for the following optimum conditions: particle size [250–400 μm], pH = [2–3], biomass content 3 g, agitation of 250 rpm, temperature of 25 °C, and initial concentration of metribuzin = 200 mg L−1.

Evaluation of modified Algerian clay as mineral adsorbent was done for its adsorbing capacity on copper (Cu) and Zinc (Zn) cations. The results obtained show a rapid kinetic adsorption for both metals (less than 2 h) following the pseudo-second order model with high elimination rates of 67.2 and 61.8% for Cu and Zn respectively. The adsorption isotherms analyzed with Langmuir model revealed a correlation with the experimental values. While the use of obtained chitosan at room temperature, as flocculent coagulant, accelerates the decantation of the colloidal particles in suspension generated after adsorption process.

Soil contamination by heavy metals is one of the major environmental problems in the world. In such environments, especial species of plants have the ability to grow, adaptation and uptake the heavy metals. Although the use of Brassica familyplants heavy metals phytoremediation is well known, there is little information about the impact of Brassica napus L increasing concentrations of heavy metals on parameters. A three-month study was carried to evaluate: the capacity of Canola Brassica napus L plants to phytoextract Zn from artificially polluted soil and the study the effect of increasing Zinc doses on the parameters of canola Brassica napus L (stem height, root length, leaf number, and dry matter yield). The findings show that Canola is a Zinc hyperaccumulator and high doses of it do not affect Canola growth. The statistical study after three months (12 weeks) of experimentation revealed a significant positive correlation between increasing Zinc doses and the four studied parameters.This study reveals that Canola plants were highly tolerant to metal pollution Zn and capable of reaching high biomass values in the presence of Zn.

This work was designed to study the effectiveness of hydrogen peroxide photolysis on the degradation of malathion pesticide in an aqueous medium. Experiments were performed in a static reactor with a low-pressure mercury vapor lamp at initial organophosphorus concentrations of 10−3. The first result obtained showed that the system H2O2/UV can completely oxidize the organophosphorus compound. The oxidation yields obtained using the static reactor depended on the reaction time, the initial concentration of H2O2, and the initial pH solution. However, the oxidation efficiency may be reduced by the presence of radical traps in the reaction medium. Moreover, a model of the hydrogen peroxide photocatalysis is also presented in this paper. The use of experimental design and in particular the response surface methodology (RSM) in addition to the full factorial design allowed the determination of the influence of the simultaneous effects and interaction of the operating parameters on the performance of the photo degradation Demim et al. Ecol. Eng. 57 (2013) 302; Ecol. Eng. 61 (2013) 426; Boudjema et al. Desalin. Water Treat. 1065. 10.1080/19443994.2015.449. Indeed, the operating parameters studied in this research work were the initial concentration of malathion, H2O2 catalyst volume and the pH of the solution. The results found showed that the application of the RSM allowed describing correctly the effect of these three operating parameters on the treatment efficacy. The optimal parameter values giving a maximum yield (100%) were determined.

The aim of this study was to enhance the use of instrumental neutron activation analysis (INAA) for long-term monitoring of air pollution and to identify critical sources of air pollution. For the collection of total suspended particulate matter (TSP), a filter unit low volume sampler (LVS) was employed. One hundred and seventeen samples were collected during 2010, 2011, and 2012, both on weekdays and weekends at a monitoring station located in Draria city, a suburban site near Algiers, Algeria. The concentrations of 25 trace elements (As, Br, Ca, Cd, Ce, Cl, Co, Cr, Cs, Eu, Fe, Gd, Hf, K, La, Mn, Mo, Na, Sb, Sc, Se, Sm, Sr, V, and Zn) were determined by INAA using short and long neutron irradiation technique. Generally lower concentration values were observed during the weekends compared to the weekdays for almost all elements. The mean TSP concentration (34.8 μg/m3) showed a seasonal pattern with higher levels during summer. The weekday/weekend ratio of TSP was 1.3 higher during summer than in winter. The concentrations of the elements Sb, Se, and Cd are found to be highly enriched in atmospheric particulate matter. According to their high enrichment factors (EFs), it was possible to establish that these elements are of anthropogenic origin coming from automobile exhausts which is the main source of emission in this area. The typical suburban background TSP and trace element levels were compared with literature data from other regions around the world, and were lower than those reported in an urban site in Algiers in a previous study. Significant correlations between elements were found (Pearson's coefficients > 0.5) suggesting that the contaminant trace elements may be discharged from the same sources.

The purpose of this study is to remove hexavalent chromium and COD from wastewater by electrocoagulation. The experiments were carried out in an electrochemical reactor using iron sacrificial electrode. Operating parameters such as current density (100, 150, 200 A/m 2 ), pH of the effluent, number of electrodes and their materials were studied. The optimal operating conditions were determined and applied to the process. The results show that this process of removal can reduce chromium (VI) into chromium (III) with an output of 100% and 95.95% of COD in a relatively short reaction time and at low cost.

The main purpose of this study was the chitin enzymatic hydrolysis enhancement by a pretreatment, consisting of chitin exposure to gamma radiation at several doses, ranging from 15 kGy to 210 kGy. The solid chitin molecular weight reduction achieved by Co-60 gamma rays treatment reached a 90% rate at the t used, with a dose of 210 kGy. The partial depolymerization of chitin was realized by irradiation allowing an enzyme affinity increase toward this substrate. The monomers and oligomers obtained from their radiated chitin production rate were almost 100%. It was also demonstrated that the NAG production by enzymatic hydrolysis of irradiated chitin at 210 Gy follows Michaelis–Menton kinetics.

de Recherche en technologie des Semi-conducteurs pour l’Energetique (CRTSE), 2, Bd Frantz Fanon BP140, Alger–7 merveilles, 16038, AlgeriaUniversite de BOUIRA, Pole Technologique, 10000, Bouira, AlgeriaA R T I C L E I N F OArticle history:Received 1 October 2014Received in revised form 18 December 2014Accepted 3 January 2015Available online xxxKeywords:OpuntiaCoagulation–flocculationTurbidityWater treatmentA B S T R A C T

This study’s main purpose is to contribute to the Oued Smar landfill leachate decontamination. To achieve this aim, the advanced oxidation process (AOP) via heterogeneous photocatalysis (TiO2/UV) was coupled with seeded bioreactors with different inoculums types (raw leachate, soil extract and activated sludge). The results obtained after heterogeneous photocatalysis show that the reduction is comprised between 50 and 84% of the initial COD maintained at pH 5. However, this treated leachate cannot be reused or discharged without another treatment into the environment. The new BOD5/COD ratio ranging between 0.045 and 0.18 are favorable for biological treatment. The AOP–bioreactor coupling allowed an abatement of 90% of the initial BOD5 and 87% of the initial COD leachate surface reduction with a final value of 1000 mg O2/L. However, this value is not yet conformed to the norm. The biological treatment has shown the landfill indigenous microorganism's ability to degrade the irradiated leachate since, the mineralization dissolved organic carbon (DOC) rate is almost identical to the value obtained by activated sludge. These results encourage the supposition to recycle the irradiated leachate in the landfill which now possess a biopile behavior (loop AOP + landfill).

The possibility of using a plant material, prickly pear cactus, Opuntia ficus Indica , juice (OFIJ), for conditioning the Beni-messous wastewater treatment plant sludge was examined. Optimum dosage of OFIJ was found to be 0.4 g kg −1 of dry matter. The residual turbidity, the dryness of filtration cake and the specific resistance of filtration were found to be 2.5 NTU, 24% and 0.13 × 10 12 m kg −1 respectively. The results obtained with OFIJ were compared to those obtained with polyelectrolytes: Chimfloc C4346, a cationic polymer, Sedipur NF 102, a non-ionic polymer and Sedipu AF 400, an anionic polymer, and inorganic conditioners, FeCl 3 and Al 2 (SO 4 ) 3 . The optimum dosages of those conditioners were found to be 0.4 g kg −1 for OFIJ, 0.8 g kg −1 for Chimfloc C4346, 80 g kg −1 for FeCl 3 and 60 g kg −1 for Al 2 (SO 4 ) 3 .

In the food processing industry shrimp shells (Parapenaeus longorostris) have great commercial value because they are rich in chitin (24 wt%), protein (40 wt%), lipids, pigments and flavor compounds. In the present study protein recovery by ultrafiltration was examined during isolation of chitin from shrimp shell P. longirostris. Up to 96 wt% of the proteins could be removed (i.e. deproteinization) from the shrimp shells by incubating them in NaOH (2 N) over 2 h, at T = 45 °C, and solid to solvent ratio of 1:2 (w/v). A solute rejection coefficient (R0) of 97% was obtained in the ultrafiltration process to recover proteins from deproteinized shell waste water. The protein concentration process which was carried out beyond the critical flux of 380 L/h.m2, at a trans-membrane pressure of 3 bars, and a tangential velocity of 5 m/s was found to reduce the hydrolysate volume by a factor of 2.4. Due to a reduction in organic matter in the effluent, the chemical oxygen demand (COD) of the permeate was reduced by 87%.

a b s t r a c t The present work investigates a novel water denitrification technique based on immobilized bacterial biomass using various plastic wastes as supports PVC (polyvinyl chloride), HDPE (high density poly- ethylene) and LDPE (low density polyethylene) in packed columns. The efficiency of these supports is compared with a conventional support, granular activated carbon (GAC). The results obtained for denitri- fication under various operating conditions showed that working at a high fluid velocity does not affect the bacterial behavior adversely. The denitrifying bacteria were able to treat water at an inlet nitrate concentration of 600 mg L −1 with removal efficiency near to 100%. The column packed with porous GAC as a support quickly became plugged in contrast to the nonporous LDPE which possesses a rough surface for film support and delivers almost the same performance as GAC. It was found that sulfate ions promote denitrification, but chloride inhibits it. The effectiveness of the packed-bed process is not diminished significantly by the coexistence of both types of ion in the feed stream.

a b s t r a c t This study evaluated Brewer's spent grain as media for denitrification processes in treating groundwater. A laboratory scale reactor was inoculated with anaerobic sludge from a waste-water treatment plant. Optimization of running conditions were investigated under various parameters including: hydraulic retention time (HRT), influent nitrate loading and pH. The experimental results demonstrate that the opti- mum reaction parameters were: HRT = 100 min; N-NO3 = 200 mg L−1; pH = 7.5-7.9. Vertical study showed that hydraulic retention time and pH affect significantly the nitrate removal, while nitrate loading do not affect the denitrification process.

The purpose of this study was to restore diesel-contaminated soil using biological process and then to study microbial metabolism followed by biodegradation of hydrocarbons. To reduce the processing time of soils biopile process, initially a part of the contaminated soil was enriched with nutrients. The determination of the optimal conditions for biodegradation of contaminants in soil after excavation (ex situ) was performed. Biopile technique was able to restore the diesel-contaminated soil. Indeed, after 76 days, the soil was decontaminated with total petroleum hydrocarbon (TPH) removal rate of about 85%. This performance was achieved during the first twenty days of treatment. The simple fractions (alkanes and aromatics) were firstly degraded followed by the complex fractions.

A feasibility study of an innovated denitrification process is achieved in this present work. It consists of a combination of the electrodialysis (ED) and the Column of Immobilized Biomass on Granular Activated Carbon – CIBGAC. In order to perform the electrodialysis process, the influence of various parameters such as current intensity, chloride, and sulphate concentrations were estimated. Therefore, an optimum efficiency of the denitrification for an applied current intensity value of 50 mA was obtained. The competition between the chloride and nitrate ions was encountered using the electrodialysis process inducing a slow electromigration of the nitrates. In contrary, the presence of sulphate ions had no influence on the electrodialysis during the denitrification. On the other hand, the biological denitrification of brines by electrodialysis was carried out. A clear decrease of pH was observed from 7.5 to 6.2 and the monitoring of the nitrate and nitrite ions through the bio-compartment affirmed the efficiency of this process. The successful establishment of the hybrid denitrification process was realized. Indeed, the treated water in dilute compartment was in conformity in terms of nitrates concentration and even more the concentrations of different ions are below the amounts recommended by the World Health Organization (WHO). TOHOH he brine solution after biological treatment agrees with WHO standards in terms of nitrate and nitrite ions.

Chitosan is a biopolymer, biodegradable, non-toxic and widely abundant in nature. Our study presents an investigation on the application of this biopolymer in treatment of Beni- Amrane dam water by coagulation flocculation process. In this study, the raw water from Beni-Amrane dam characterized by high turbidity was treated using chitosan as primary flocculant and as coagulant aid with aluminum sulfate (alum). The performance of this process was evaluated by measuring the supernatant residual turbidity for various values of chitosan concentrations. The obtained results are in favor of chitosan. With low concentrations, chitosane used alone is able to reducing 85% of initial turbidity. In the case of using chitosane in combination with alum, highest turbidity removal (97%) was carried out with 0. 15 mg/l of chitosan and 20 mg/l after 45 minutes of settling time. At this value, a very low residual aluminum (0, 02 mg/l) was registered. The organic carbon contribution on the turbidity coagulation flocculation performance is negligible because chitosan is used in small doses. Hence, chitosan could be used as natural coagulant aid for drinking water treatment with lowest risks of organic release. These properties, combined with its non-toxicity, make the chitosan as the best substitute to conventional synthetic polyelectrolytes used so far.

In the present study, anticancer activities of chitin, chitosan and low molecular weight chitin were evaluated using a human tumour cell line, THP-1. A molecular weight-activity relationship and an electrostatic interaction-activity relationship were determined. The cytotoxic effects of chitin and derivatives were also evaluated using a normal human foetal lung fibroblastic cell line, MRC-5 and the specific cytotoxicity of chitin and derivatives to tumour cell lines was demonstrated. The high antitumour effect of low molecular weight of chitin was established.

The aim of this study was to restore diesel-contaminated soils by means of a biological process and to determine microbial metabolism which accompanies biodegradation of hydrocarbons. Restoration of diesel-contaminated soil was achieved using the biopile technique. The principle was to optimize conditions for biodegradation of contaminants in the soil after excavation (ex situ). Indeed, after 40 days. The predominant microbes recovered from the microcosms were bacteria and the achieved rate of soil decontamination was 70%. Synergy was recorded between yeasts and bacteria for diesel biodegradation. This is called cometabolism. This analytical method is a new approach in microbiological analysis of the microorganisms responsible for the biodegradation of hydrocarbons. Original results were obtained consisting of two different bacteria growth phases during the biodegration of diesel in the biopile.

The antimicrobial activities of chito-oligosaccharides against four Gram-positive and seven Gram-negative bacteria were compared to chitosan and chitin with an emphasis on the effects of biopolymer molecular weight (Mv) and degree of deacetylation (DD). Chitin was isolated from shrimp ( Parapenaeus longirostris ) shell waste by sequential chemical treatments. Chitosan and its oligomers N-acetyl chito-oligosaccharides and chito-oligosaccharides were prepared by deacetylation and chemical hydrolysis, respectively. Chitin exhibited a bacteriostatic effect on Gram-negative bacteria, Escherichia coli ATCC 25922, Vibrio cholerae , Shigella dysenteriae , and Bacteroides fragilis . Chitosan exhibited a bacteriostatic effect on all bacteria tested, except Salmonella typhimurium . The oligomers exhibited a bactericidal effect on all bacteria tested.

The main purpose of this work was to extend the application of a novel separation technique to the removal of pesticides from superficial waters. The technique is based on the process of adsorption on granular activated carbons (GAC) that are initially activated by an electrical potential. The activation technique, so-called electro-activation, was applied to a column of GAC, in which the adsorption of the pesticide metribuzin was investigated under process-affecting variables, namely, the electrochemical potential, the initial metribuzin to GAC concentration ratio and the ionic strength of the adsorbed solution, which was varied by adding solutions of NaCl, KCl and Na2SO4. The results obtained for a solution with an initial metribuzin to GAC concentration ratio of 30 mg/g, an electrical potential of −200 mV/SCE and an NaCl solution of 2 g dm−3 showed a maximum increase in the adsorption capacity of metribuzin of 38% compared to that obtained without the electro-activation of GAC.

The objective of this study is to develop by chemical synthesis of hydroxyapatite, an adsorbent powder to be used for the decontamination of waters by metal ions. Moreover, the effectiveness of chitosan produced from shrimp waste to flocculate turbid suspensions produced from the previous treatment is evaluated. The study of adsorption of Cu and Zn on hydroxyapatite showed a removal efficacy of 88-95% with relatively fast kinetics. Between the two metals, copper presents the higher adsorbing tendency. However, the use of hydroxyapatite, as an adsorbent, generates turbid suspensions which are hardly settleable. For this reason we evaluated the effectiveness of chitosane to flocculate the hydroxyapatite turbid suspensions. The outcome of this study is the great efficacy exhibited by the chitosan to remove the turbidity of various samples of hydroxyapatite of different fractions. The elimination rate after 30 minutes of settling in all cases exceeds 98%. The effect of the dose of chitosane and the effect of pH on the coagulation-flocculation process were studied and the respective results show that the optimal doses range from 0.2 to 2 mg of chitosane/ L corresponding at optimal pH between 6 and 7.

In this paper, application of electrocoagulation using common iron electrode to a simulated photovoltaic wastewater after precipitation with lime (Ca(OH)2) was investigated. Electrocoagulation process delivers the coagulant in situ as the sacrificial anode corrodes, while the simultaneous evolution of hydrogen at the cathode allows pollutant removal by flotation. Several working parameters, such as initial pH, applied potential and distance between the electrodes, were studied in an attempt to achieve higher fluoride removal efficiency. The optimum conditions for the process were identified as pH = 6, the distance between electrodes = 1 and an applied potential of 30 V. Furthermore fluoride removal is under the direct discharge standards.Results showed high effectivenessof the electrocoagulation method in removing fluoride from aqueous solutions.

Electrocoagulation of leachate from OUED SMAR (North-Algeria) town landfill. ► Removal of COD, total-N, color and turbidity was satisfactory with 500 A/m2. ► Aluminium was found to be more effective in treating leachate than Iron. ► Iron electrodes are energetically efficient than aluminium. ► Operating cost was 0.47 US$/m3 with Fe electrodes and 0.54 US$/m3 with Al.

In this paper, Rhodobacter sphaeroides CIP 60.6 strain was newly used for the biohydrogen production in a perfectly shaken column photobioreactor, grown in batch culture under anaerobic and illumination conditions, to investigate the effects of some physico-chemical parameters in microbial hydrogen photofermentation. Luedeking–Piret model was considered for the data fitting to find out the mode of hydrogen generation and the relationship between the cell growth and hydrogen production. The results show that, both growth cells and resting cells can produce hydrogen at light intensities greater or equal to 2500 lux, however, at the weak intensities hydrogen is a metabolite associated to growth. Growth rate and hydrogen production rate increase with the increasing of light intensity. Moreover, hydrogen production rate become higher in stationary phase than that in logarithmic phase, with the enhancement of light intensity. Maximum hydrogen production rate obtained was 39.88 ± 0.14 ml/l/h, at the optimal conditions (4500–8500 lux). Modified Gompertz equation was applied for the data fitting to verify the accuracy and the agreement of the model with experimental results. It is revealed that, in the modified Gompertz equation, the lag time represents time for which hydrogen production becomes maximal, not the beginning time of hydrogen production. The stop of stirring reduced hydrogen production rate and created unstable hydrogen production in reactor. The pH ranges of 7.5 ± 0.1 were the favorable pH for hydrogen production.

The main purpose of this study was to evaluate the removal of the pesticide metribuzin from contaminated groundwater by means of an electrochemical reactor equipped with iron cylindrical concentric bipolar electrodes. The optimization of the experimental parameters such as current density, pH, initial concentration of metribuzin and salt concentration, for pesticide removal was first assessed. The elimination of the pollutant was found to be up to 89%. When this electrochemical process was combined with an ultraviolet oxidation process, the contaminant removal rate reached 95%. However, the results also suggested that the addition of hydrogen peroxide may reduce the process performance possibly due to increased turbidity.

The main purpose of this study was to investigate the removal of the chemical oxygen demand (COD) from olive mill wastewater (OMW) by the combination of ultrafiltration with electrocoagulation process. Ultrafiltration process equipped with CERAVER membrane was used as pre-treatment for electrochemical process. The obtained permeate from the ultrafiltration process allowed COD removal efficiency of about 96% from OMW. Obtained permeate with an average COD of about 1.1 g dm −3 was treated by electrochemical reactor equipped with a reactor with bipolar iron plate electrodes. The effect of the experimental parameters such as current density, pH, surface electrode/reactor volume ratio and NaCl concentration on COD removal was assessed. The results showed that the optimum COD removal rate was obtained at a current density of 93.3 A m −2 and pH ranging from 4.5 to 6.5. At the optimum operational parameters for the experiments, electrocoagulation process could reduce COD from 1.1 g dm −3 to 78 mg dm −3 , allowing direct discharge of the treated OMW as that meets the Algerian wastewater discharge standards ( −3 ).

This work focused on kinetic, equilibrium and thermodynamic studies on aluminum biosorption by Streptomyces rimosus biomass. Infrared spectroscopy analysis shows that S. rimosus present some groups: hydroxyl, methyl, carboxyl, amine, thiol and phosphate. The maximum biosorption capacity of S. rimosus biomass was found to be 11.76 mg g(-1) for the following optimum conditions: particle size, [250-560] μm, pH 4-4.25, biomass content of 25 g L(-1), agitation of 250 rpm and temperature of 25 °C. Langmuir, Freundlich and Dubinin-Radushkevich (D-R) models were applied to describe the biosorption isotherms at free pH (pH(i) 4) and fixed pH (pH(f) 4). Langmuir model is the most adequate. With fixed pH, the maximum biosorption capacity is enhanced from 6.62 mg g(-1) to 11.76 mg g(-1). The thermodynamic parameters (ΔG°, ΔH° and ΔS°) showed the feasibility, endothermic and spontaneous nature of the biosorption at 10-80 °C. The activation energy (Ea) was determined as 52.18 kJ mol(-1) using the Arrhenius equation and the rate constant of pseudo-second-order model (the most adequate kinetic model). The mean free energy was calculated as 12.91 kJ mol(-1) using the D-R isotherm model. The mechanism of Al(III) biosorption on S. rimosus could be a chemical ion exchange and carboxyl groups are mainly involved in this mechanism.

In this work, treatment of synthetic fluoride-containing solutions by electrocoagulation method using aluminium electrodes has been studied. Electrocoagulation was investigated for applied potential (10–30 V), electrolysis time and supporting electrolyte (NaCl) concentration (0–100 mg/L). The results showed that with increasing applied potential and electrolysis time, the Al 3+ dosage increases, and thereby favouring the fluoride ions removal. It was also observed that defluoridation is dependant on the concentration of supporting electrolyte. Finally, X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy of X-rays and Fourier transform infrared spectroscopy were used to characterize the solid products formed by aluminium electrodes during the EC process.

The sorption of divalent cadmium and copper ions from aqueous solutions on natural and synthetic hydroxyapatite was investigated by the batch method and under dynamic conditions in columns at 22 °C and pH 5. The effect of cadmium and copper concentration on sorption was studied. Both types of apatites are efficient, despite their different composition and morphology. The sorption mechanism involves an ion exchange for Cd(II), while Cu(II) leads to precipitation of a newly formed solid. Thus, the sorption efficiency depends on the experimental conditions and the specific physicochemical properties of the apatites used. The sorption isotherms were fitted to the Langmuir equation.

The aim of this paper is to propose an efficient and low-cost treatment of chemical mechanical polishing wastewater process based on electrocoagulation with iron bipolar electrodes. The performance of a pilot scale electrochemical reactor equipped with iron bipolar electrodes and an anode active area surface of about 170 cm2 was studied. In addition, sludge settling after electrocoagulation were characterized. The pilot study yield promising results, suggesting that further in-depth development study is worth to be considered in a future work.

Treatment of chemical mechanical polishing (CMP) wastewater was investigated. The CMP wastewater, as obtained from surface treatment of photovoltaic wafers, was characterized by high suspended solids, high nephelometric turbidity unit (NTU), chemical oxygen demand (COD) and green color. This study determines the feasibility of CMP wastewater treatment by the electrocoagulation process. The COD concentration of the CMP wastewater was found in the range of 700 mg/l which is below the discharge standards. The analysis of the wastewater before and after electrocoagulation shows that the electrochemical process was a total barrier for the metal species, color and a significant reduction in the concentration of the fluoride and sulfate ions.

The purpose of this paper is to propose an efficient and low cost defluoridation process based on electrocoagulation with aluminium bipolar electrodes. The performance of a pilot scale electrochemical reactor equipped with aluminium bipolar electrodes with an anode active area surface of about 1.6 m2 was studied. The pilot study yielded promising results, suggesting that further in-depth development studies are justified.

A novel technique to regenerate adsorbent column is presented. The process used is based on the utilization of an electrochemical cell which regenerates several saturated adsorbent bed. This paper presents the regeneration of the activated alumina (AA) bed saturated by fluoride ions. The results obtained in this study demonstrated that desorption of fluoride from activated alumina is a rapid process. Most of the fluoride content desorbed within 6–15 min. The utilization of the electrochemical cell allows a complete desorption of the fluoride under optimum conditions. The reduction of about 90% of the sodium hydroxide amount was attained by the electrochemical process. A study of adsorption–regeneration cycles showed that the electrochemical technique was more efficient than current techniques. A 95%, recovery of the adsorption capacity was realized with the electroregeneration system. In addition, the volume of water used to regenerate the saturated bed was lower than for current regeneration techniques. The washing did not exceed 6% of the treated water volume. The electrodesorption operation was successfully applied for fluoride desorption from saturated activated alumina column by natural water with strong mineralisation.

The purpose of this paper was to determine the effect of the static deployed metal sheet on the performance in the ultrafiltration process. The sheet was first utilized to provoke turbulence near the membrane, and at the same time as an anode to create a pulsed electric field. The electro-ultrafiltration module reduced the global membrane resistance by combining three factors: turbulence created by the static metal deployed sheet, the turbulence induced by the formation of oxygen bubbles just near the membrane skin and the electrophoresis of the protein by the pulsed electric field. The application of pulsed electric field of about E = 700 V/m allowed an increase of the permeate flux by about 300%. The addition to the feed solution of activated alumina (AA) as a dynamic turbulence promoter shows that the presence of the AA considerably reduced the effect of the turbulence induced by the formation of oxygen bubbles and the electrophoresis of the protein. Nevertheless, the utilization of an electric field (E = 700 V/m) made an increase of the permeate flux of about 10% possible.

The purpose of this work was to determine the effect of the static metal deployed sheet on the performance of the ultrafiltration process. The sheet was first utilised to provoke turbulence near the membrane, and at the same time as an anode to create an electric field. It was shown that the electro-ultrafiltration module was more efficient for both low crossflow velocity and BSA initial concentration. The global hydraulic membrane resistance may be reduced by half in all cases. The polarisation layer and fouling membrane appeared reversible phenomena, which may be controlled by appropriate electric field strength.

The purpose of this paper is to suggest an efficient defluorination process which does not require a big investment. For this, the electrocoagulation process with aluminium bipolar electrodes was used. In the first step, the influence of parameters such as inter-electrode distance, fluoride concentration, temperature and the pH of the solution, were investigated and optimized with synthetic water in batch mode. In the second step, the optimization process was continued with Oued Souf water (south Algeria) where the influence of the current density and the area/volume ratio on the defluorination process was evaluated. The electrocoagulation process with aluminium bipolar electrodes permitted the defluorination of Sahara water without adding soluble salts to the treated water. The aluminium–fluoride weight ratio attained 17/1.

Nadjib Drouiche*, Hacene Mahmoudi, Nabil Mameri, Hakim Lounici, Norredine Ghaffour Laboratory of Environmental Biotechnologies 10, Avenue Hacene Badi El-Harrach, Algiers, Algeria Tel./Fax +213 21433511; email: nadjibdrouiche@yahoo.fr Faculty of Sciences and Engineering Sciences, Hassiba Ben Bouali University-Chlef, Algeria Middle East Desalination Research Center, P.O. Box 21, P.C.133, Muscat, Sultanate of Oman

A new technique based on the combination of an activated alumina column and an electrochemical system for fluoride removal from water is reported in this study. In the first step, the optimization of the process was achieved under various experimental parameters (volumetric flow, temperature, pH, initial fluoride concentration and hardness) with a synthetic solution. The comparison of the performance of the current activated alumina process and the electrosorption system proved to be more efficienct than the latter in removing fluoride from water. Thus, the fluoride sorption capacity at the breakthrough point of the activated alumina column reached 3.8 mg F − /L. It was increased by about 60% by means of the electrochemical process than the results obtained in current mode. Moreover, it was found that the electrosorption system could be utilized to regenerate the saturated activated alumina. In the second step, the electrosorption process was utilized to treat Sahara drinking water naturally contaminated with fluoride (3 mg/L) under optimum conditions previously determined. The electrosorption process coupled with activated alumina column has been successfully applied for fluoride removal from drinking water.

Concentration polarisation is one of the main limitations of permeate flux through membranes. A conventional crossflow ultrafiltration apparatus was modified by the inclusion of electrodes which permitted an electric field to be produced across the ultrafiltration membrane. This study examined the impact of operating parameters on fouling including flux, velocity, transmembrane pressure and electric field. Studies of the EF-UR process with bovine serum albumin (BSA) in the range of 1–5 g/l demonstrated a 25–50% increase of the flux permeate compared to the case of 0 electric field.