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In recent years, the increasing threat to ground water quality due to human activities has become a matter of great concern. The ground water quality problems present today are caused by contamination and by over exploitation or by combination of both. Reverse osmosis (RO) desalination is one of the main technologies for producing fresh water from sea water and brackish ground water. Algeria is one of the countries which suffer from the water shortage since many years, so desalination technology becomes inevitable solution to this matter. In this study, a comparison is provided of results of reverse osmosis desalination for three different qualities of brackish water from the central-east region of Algeria (Bouira and Setif Prefectures), wherein they cannot use it as human drinking or in irrigation systems. The main objective of our study is to establish a comparison of the reverse osmosis membrane TW30-2540 performances in the term of (permeate flow, recovery rate, permeate total dissolved solids – TDS and salts rejection) under different operation pressures (each one takes a time of 720 second for pilot scaling). In order to make an overview comparison between the experimental and the simulated results we used ROSA (Reverse Osmosis System Analysis) software. At the end of this study we noted that, the simulated results are lower than the pilot scaling values and the most removed salts are the sodium chlorides with 99.05% of rejection rate.

Reduction of nitrate to nitrogen is critical for wastewater treatment process. The present work proposed a promising approach to improve the activity of denitrifying activated sludge by using low frequency ultrasonic treatment. Batch activity assays showed that when ultrasound was applied, denitrification performance was 2.64 higher than the control. Kinetic analysis of nitrate removal rate versus ultrasonic power and duty cycle was performed to investigate the effect of operational parameters on activated sludge activities. The best stimulating effect was observed at 40 W ultrasonic power and 40% duty cycle. The above results demonstrated that ultrasonic stimulation can be used as a technique for enhancing bacterial activities for water treatment. Studies of other parameters that also affect the denitrification under ultrasound are under way.

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.

Chitosan, an important biopolymer with many uses, is made by deacetylation of chitin. Classical hydrolysis at high temperatures (above 100 °C) in 50 % concentrated sodium hydroxide during several hours produces chitosan, a poly-beta-glucosamine. This chemical deacetylation step is often performed under pressure in boiling ethyleneglycol and tends to degrade polymer chain length, thus the interesting polymer properties. It is convenient to search for a more economical production pathway in order to make chitosan available for environmental applications, such as use in water suspended matter flocculation. Chitin was extracted from the exoskeletons of shrimps and its deacetylation kinetics was followed for 35 days at 20 and 35 °C. The results obtained using different techniques (conductivity, viscometry, 13C NMR and thermogravimetry) showed that the deacetylation degree of chitin increased with the incubation time reaching 99 and 88 % at 35 and 20 °C, respectively, after 35 days. Moreover, during the incubation time, the molecular weight of chitosan showed moderate decrease compared to deacetylated chitin at high temperature. Clarification or urban waste water with chitosan biopolymer demonstrated good results at 1.5 mg/L concentrations.

In this study, the application of full factorial design and a surface response methodology was used to model the two-factor influence. Time and current intensity on bacterial biomass, color, turbidity, and natural organic matter (NOM) removal from Oued El Harrach River were discussed. A factorial experimental design was used to investigate the bacterial biomass and color removal from Oued El Harrach River situated in northern Algeria which is treated by electrocoagulation using iron plate electrodes. However, a response surface methodology (RSM) was used to reduce the turbidity and NOM. The bacteria removal efficiency was determined after 30 min of treatment. The combined effects of operating parameters on removal turbidity and NOM were also analyzed. A regression model was found to fit the experimental data very well. Besides, the results were statistically analyzed using the student’s t-test, analysis of variance, F-test, and lack of fit in order to define the most important process variables af...

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 .

The economic evaluation of defluoridation of Sahara groundwater is presented for three processes: electrodialysis, reverse osmosis and the electrochemical bipolar reactor (EBR). The economic study was accomplished for a drinking water unit production of 100 m3/h. One of the findings was that the costs per cubic metre of treated water obtained with different processes were not too costly for the states of the North African region. The results also indicated that the most efficient process uses the EBR, followed by the electrodialysis and reverse osmosis process. However, the water produced by the first process does not have the required quality for drinking water; therefore, it has to be utilised for agricultural purposes. On the other hand, the electrodialysis unit do produce quality drinking water and appears to be an interesting solution to the fluorisis disease. Reverse osmosis method technique provides higher quality of drinking water with a salinity not exceeding 0.1 gsalts/l.

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.

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 this study, synthesize hydroxyapatite (HA) suspensions sedimentation was used after usual terms as support for adsorption of heavy metals ions. Thus, the effectiveness of chitosan, produced from shrimp waste, in the flocculation of turbid suspensions resulting from the treatment of water contaminated with heavy metals was studied by adsorption on HA. Different particles sizes of HA were mainly controlled in this work (an average of granule size ranging from 1.6 to 63 μm). The results of Cu2+ and Zn2+ adsorption on HA showed relatively fast kinetics, with removal extent of 88–95 % by varying the initial total metal concentration. High removal rates were obtained for Cu2+. Chitosan was found to be able to eliminate by flocculation more than 98 % of turbid suspensions generated by metals adsorption on HA after only 30 min of sedimentation. Effects of pH and dose of chitosan on the coagulation–flocculation process were also studied. The optimal dose of chitosan was found between 0.2 and 2 mg/L which corresponds to an optimal pH ranging from 6 to 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.

Electrocoagulation experiments were conducted with bipolar aluminium electrodes to determine the optimum conditions for the fluoride removal from synthetic photovoltaic wastewater. A high fluoride concentration in community water supplies can cause fluorosis which has a detrimental effect on human health in particular on teeth and bones. A full 23 factorial design of experiments was used to obtain the best conditions of fluoride removal from water solutions. The three factors considered were initial fluoride concentration, applied potential, and supporting electrolyte dosage. Two levels for each factor were used; supporting electrolyte (0 and 100), applied potential (10 and 30 V), and initial fluoride concentration (20 and 25 mg/L). Results showed that the optimum conditions for fluoride removal from photovoltaic wastewater containing an initial fluoride concentration of 20 mg/L were a supporting electrolyte dose of 100 mg/L and an applied potential of 30 V. These gave a residual fluoride concentration of...

The effectiveness of chitosan as a coagulant flocculant in surface water treatment has been studied. Tests were carried out in laboratory on treated and raw water. The treated water was mixed with high and low concentrations of bentonite to simulate turbid water. This treated water provides from water treatment plant of Algiers (Boudouaou site) which is supplied by both dams of Keddara and Beni Amrane. The raw water comes directly from these two dams. Chitosan with 85% degree of deacetylation and derived from crab chitin has been used. The performance of coagulation flocculation process has been assessed by measuring the supernatant turbidity for different doses of chitosan, initial turbidity, water quality and pH. The obtained results show that chitosan can be used in a large pH range. Chitosan is effective for coagulation of bentonite suspension and for raw water with high initial turbidity. Otherwise, chitosan is inefficient for raw water with very low initial turbidity. In this case, the use of chitosan as aid coagulant with aluminium sulfate (main coagulant) allows more effectiveness in removing turbidity.

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.

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 study is to investigate the possible purification of Oued El Harrach river water, which introduces significant chemical and biological pollution into the Algiers Bay ecosystem and threatens public health. This study determines the feasibility of river water treatment by electrocoagulation (EC) with aluminum electrodes. In batch tests, chemical oxygen demand (COD) and turbidity were reduced of about 80% and 95%, respectively, within 30 min. Analysis of the water before and after EC also indicates a significant reduction of microbial load. Indeed, a 99% reduction in fecal coliforms and Escherichia coli was observed. Almost total destruction of fungi was obtained.

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 technique for activation of granular activated carbon (GAC) is presented based on the electrochemical method. In this study, we investigate the effectiveness of the electroactivated GAC in removing phenol from water and determine the optimum conditions for activation. Electro-activation of the GAC appears to be an interesting technique; it requires a short electro-activation time Ta = 30 min and an optimum potential ranging from +200 mV/SCE to 400 mV/SCE. Phenol adsorption isotherms gave a limiting adsorption capacity Qm dependent on the applied potential, which at potential E=+300 mV/SCE was improved by about 55%, giving Qm = 75 mgphenol g−1 GAC.

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.

The main purpose of this study is to contribute to transform Oued Smar landfill (located in Algiers) into a recreation park with green spaces. To achieve this goal, the surface water and groundwater decontamination turns out to be vital to the success of this project. In order to achieve this objective, the effectiveness of the advanced oxidation process (AOP) by heterogeneous photocatalysis (TiO 2 /UV) regarding the landfill heavily-loaded water was tested. The analyses carried out on this water showed a recalcitrant organic matter to biodegradation. The results obtained after heterogeneous photocatalysis are relevant, an abatement of chemical oxygen demand COD of about 92% was recorded at a pH maintained at 5. However, the NH 4 + concentration remained stable at this particular pH. The results of the photodegradation kinetics modeling indicate that the reaction is therefore zero order independently of the pollutant load. However, this treated water remains non-compliant to be reused or directly rejected into the nature. The new ratios BOD 5 /COD after photo catalysis treatments are favorable to a biological treatment. For the groundwater case, the AOP has proven to be able to make it conform to the standards and can thus be used as a spray water for the recreation park. The latter will assure the natural biopile effective performance that is the landfill, by, over time, reducing the pollutant contents and increasing the water quality of the new recreation park.

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The recovery and concentration of proteins from the waste water of a fish plant was achieved by ultrafiltration. Two UF modules equipped with Ceraver and Patterson Candy International (PCI) membranes were tested. Despite different cut-off values, similar apparent rejection coefficients (70% and 80% respectively) were obtained. Optimum economic conditions were established, corresponding to average transmembrane pressures of 2.2 x10 5 and 3.8 x 10 5 Pa and tangential flow rates of 6.0 and 0.47 m s -1 for Ceraver and PCI membranes, respectively. The protein concentration in the feed solution was increased from 5 to 35 g dm -3 . The study showed that the method could reduce pollution due to organic matter by decreasing the value of the Biological Oxygen Demand after 5 days (BOD 5 ) by about 80%.

The main purpose of the present work was to develop a treatment method to regenerate granular adsorbent beds saturated with H(2)S by utilizing three electrodialysis compartments equipped with a cation or an anion exchange membrane or a bipolar membrane. Three electrodialysis compartments were utilized under various experimental parameters to determine the optimum conditions for the recovery of column particles saturated by H(2)S. The desulphurization operation is achieved with the extent of extraction close to 90% and an electric current density of about 30%. Use of the bipolar membrane makes it possible to regenerate the saturated adsorbent granules without adding chemical products. Since the only reagent was electricity, the projected economics are very attractive.

The present work deals with the removal of Metribuzin from aqueous solutions in a batch and continuous mode using electrosorption technique. This technique is based on the combination of two processes: the adsorption of Metribuzin into activated granular carbon (GAC) column and the application of the electrochemical potential. The effects of various experimental parameters (electrochemical potential, volumetric flow rate and initial Metribuzin concentration) on the removal efficiency were investigated. The pesticide sorption capacity at the breakthrough point of the GAC column reached 22 mgpesticide gGAC−1. It was increased by more than 100% when the desired electrical potential (−50 mV/SCE) was applied in comparison with the conventional GAC column in similar experimental conditions without electrical potential. Evenmore, the electrosorption technique reduced considerably the drastic decrease encountered when passing from batch mode to continuous column mode.

The purpose of this work is to evaluate the possibility of utilising an ultrafiltration process for the treatment of water from the dam in the Kabylia region of Algeria and, in particular, for the provision of drinking water to people living in dispersed small villages. The water quality was determined by measuring turbidity, and natural organic matter concentration. The results obtained with an ultrafiltration process indicate that this technique can considerably reduce suspended and organic matter. It also improves the bacteriological quality of the treated water. An economic evaluation for ultrafiltration of surface water is presented. The economic study was performed for a drinking water unit of 20 m3/h . It was found that the cost per m3 of treated water ($ 0.235/m3) obtained would not be excessively high for the states of the North African region. WaterSA Vol.27(2) 2001: 199-204

The main purpose of this paper is to determine the mechanisms which govern the adsorption of the phenol onto electro-activated carbon granules. This new activation technique allowed an increase of the performance of the adsorbent. Two models were utilised to understand the improvement in the performance of electroactivated carbon granules. The first, a simple external resistance model based on film resistance, gave acceptable predictions, with an error of less than 15%, between the theoretical results and experimental data independent of the activation potential and phenol initial concentration. The second linear model, based on diffusion phenomena, was more representative in describing the experiment than the first model. It was observed that the electro-activation method did not change the mechanism which governs phenol adsorption onto granular carbon. Indeed, the same mathematical model based on diffusion phenomena made it possible to predict with a very low error (less than 5%) the experimental data obtained for the favourable activation potential, without activation potential and with an unfavourable activation potential. The electro-activation technique makes it possible to increase the number of active sites that improve the performance of the electro-activated granular carbon compared with conventional granular activated carbon.

The zinc biosorption capacity of a Streptomyces rimosus biomass was studied in the batch mode. After a heat pretreatment, optimum conditions of biosorption were found to be: an average saturation contact time of 4 h, a biomass particle size between 140 and 250 μ m, the ambient temperature, a stirring speed of 250 rpm, and pH of 7.5. The equilibrium data could be fitted by a Langmuir isotherm equation. Under these optimal conditions, up to 30 mg Zn /g biomass , was fixed. Moreover, additional chemical treatment of the biomass by NaOH (1 mol/L), increased the biosorption capacity of about 80 mg Zn /g biomass .