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The objective of this work was to study the effect of increasing rates of salinity with and without fertilizer on the mineral nutrition of canola. It is about measuring the nitrogen, phosphorus and potassium contents in canola plant and comparing the results of each treatment (interaction between salinity and NPK fertilizer). The pot experimental included four levels of salinity S0 (control), S1, S2, and S3 and two doses of NPK fertilizer. The results showed the absence of NPK fertilizer, and salinity has a negative effect, especially with respect to S3, where the lowest nitrogen content was registered. The supply of NPK fertilizers has a significant effect on the nitrogen content of canola, where it has been recorded. The increasing concentrations of NaCl with the addition of NPK fertilizers influence the phosphorus content. The S3 level registered the highest phosphorus content. With the NPK fertilizer, the content of exchangeable potassium content in canola plant decreases with increasing the NaCl concentration, due to the antagonism between Na+ and K+. The S0 (control) registered the highest potassium content where, the S3 registered the lowest content. The application of NPK fertilizer increased the nitrogen and phosphorus content in plant of canola in a saline environment.

The electroactivity of Chlorophytum rhizospheric soil using imposed potential chronoamperometry and a characteristic cyclic voltammetry was demonstrated in the present work. Five different polarizations were tested: − 0.3, − 0.155, 0, + 0.155, and + 0.3 V/SCE. The current density had stabilized around − 0.0068 mA/m2 and − 0.03 mA/m2 at − 0.155 and − 0.3 V/SCE, respectively. However, at 0, + 0.155, and + 0.3 V/SCE, a current density had reached respectively 1.46 A/m2, 1.48 A/m2, and 0.6 A/m2. The potential + 0.155 V/SCE seemed to better stimulate the electrogenic bacteria activity of the Chlorophytum rhizosphere. Different bacterial strains had formed electroactive biofilms in response to different electrode polarizations. The Chlorophytum rhizosphere electroactivity has depended on strict anaerobes as well as facultative anaerobic bacteria under anaerobic conditions. Furthermore, the Chlorophytum rhizosphere soil had closed almost equal proportions of Firmicutes and Proteobacteria whose electroactivity seemed to depend on the Proteobacetria more than the Firmicutes and had could be thereby a suitable environment for electroactive biofilm development.

Soil salinity severely affects cultivation in arid and semi-arid regions. It causes, among other things, an imbalance in the mineral nutrition of plants which results in yields’ decrease. One of the research’s approaches to mitigate the effects of these constraints is to look at the interaction between sodium chloride and phosphorus. The aim is to study the action of phosphorus to reduce the harmful effects of salinity. This study was undertaken in a greenhouse, in a pot of vegetation. The model plant used is Sorghum (Sorghum vulgar var rocket). The interaction NaCl (S) × P is carried out with four concentrations of NaCl (S0 = 0.1 dS m−1, S1 = 2 dS m−1, S2 = 8 dS m−1, S3 = 32 dS m−1) and four doses of TSP (PO = 0 mg/pot, P1 = 200 mg/pot, P2 = 400 mg/pot, P3 = 819 mg/pot), that is 16 (SP) processing. The results obtained made it possible to identify the effect of the SP processing on the morphological parameters, on the assimilation of the NPK's major elements, and on the accumulation of proline. They clearly showed that by adding phosphorus there was a remarkable improvement as the Sorghum displayed tolerance towards salinity. This improvement is manifested by an increase in stem height, dry material yield, nitrogen and phosphorus uptake, and proline accumulation. The results obtained suggest that Sorghum culture in saline medium (EC ≤ 32 dS m−1) is possible.

The transport phenomena across polymeric membrane may be enhanced by applying various strengths inside or outside the system. Recently, polymer inclusion membrane (PIM) has been considered one of the most popular methods that acts as a sink for the contaminant and immobilizes it. In the literature, there is no report about how to achieve the synthesis of multi-layer PIMs. In this paper, an improvement of a novel category of membrane without carrier for performing ion separation is reported. Different membranes were elaborated from binary mixtures of polymers, cellulose triacetate (CTA), polymethyl methacrylate (PMMA) and polyvinyl chloride (PVC) using 2-nitrophenyl octyle-ether (NPOE) as plasticizer and carrier in the same time, in order to increase specific interactions between the different polymers. The membranes (Polymer 1– NPOE – Polymer 2) were synthesized by phase inversion method modified by changing the procedure of a plasticizer/carrier addition and characterized by FTIR, TGA, SEM, zeta potential and contact angle. The CTA-based membranes exhibited well-defined pores partially filled with the second polymer and NPOE. Overall, our results showed that the addition of NPOE resulted in homogeneous membranes with modified physical properties, such as thickness, and hydrophobicity. A study of transport of Pb(II) using the synthesized membranes was studied. Dialysis experiments of lead ions across a polymeric membrane have shown that (CTA + NPOE + PMMA) and (PMMA + NPOE + PVC) membranes proved a good performance in one stage by fixing 12.15 and 25.31% of lead, respectively, without any additionally added carrier and acids. These results confirm the affinity between a basic polymer (poly-methyl methacrylate) and the metallic ion (Pb2+).

In this study, spherical beads have been prepared by ionotropic gelation of sodium alginate using two types of cross-linking, physical cross-linking in the presence of Ca2+ ions and chemical cross-linking which was made with epichlorohydrin for environmental applications. The different beads of alginate were characterized by Fourier transform infrared spectroscopy, optical microscopy, scanning electron microscopy, and X-ray diffractometry to provide evidence of successful cross-linking. The physicochemical properties of the beads such as the average diameter, water content, the zero charge point, and the density were also determined. The efficiency of the beads as biosorbent for the removal of dyes is assessed using methyl violet (MV) as a model molecule. A comparative adsorption performance of wet calcium alginate beads (WCaAB), dry calcium alginate beads (DCaAB), wet epichlorohydrin cross-linked alginate beads (WEpAB), and dry epichlorohydrin cross-linked alginate beads (DEpAB) was made. The adsorption of methyl violet MV on cross-linked alginate beads was found to be comparatively higher than that of WCaAB, DCaAB, and WEpAB. The extent of adsorption of methyl violet MV onto cross-linked alginate beads (DEpAB) was found to be a function of the pH of the solution, contact time, sorbate concentration, amount of beads and stirring speed. The kinetics adsorption of MV onto cross-linked alginate beads (DEpAB) was investigated using the pseudo-first-order, pseudo-second-order, and intraparticle diffusion kinetic models. The results showed that the pseudo-second-order kinetic model adequately describes the experimental data.

Batch adsorption experiments were carried out, aiming to remove phosphates ions from water samples using powdered marble (PWM) as an effective inorganic sorbent, which is cheap, widespread. Operating parameters such as pH, sorbent, and phosphates concentration, shaking time, and temperature influencing the sorption process, were investigated. The results obtained showed that the sorption of phosphates ions onto PWM was fitted well with the linear Langmuir model over the concentration range studied. Phosphate removal by PWM was a pH-dependent process. Mechanisms for phosphate removal mainly involved adsorption and precipitation, varied with equilibrium pH of the solution. The sorption on PWM increased with increasing temperature. The pseudo-second-order model characterized the kinetics of the removal process by PWM adsorbent. The synthesized adsorbents before and after phosphate adsorption were characterized by powder X-ray diffraction and Fourier-transform infrared spectroscopy. The calculated thermodynamic parameters (∆G°, ∆H°, and ∆S°) showed that the adsorption of phosphate onto powdered marble was feasible, spontaneous and endothermic at 15–40 °C.

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.

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.

The approach of the present work is based on the use of poly (methylmethacrylate) (PMMA) polymer, which is compatible with PVDF and TiO2 nanoparticles in casting solutions, for the preparation of nano-composites membranes using a safer and more compatible solvent. TiO2 embedded poly (vinylidene fluoride) (PVDF)/PMMA photocatalytic membranes were prepared by phase inversion method. A non-solvent induced phase separation (NIPS) coupled with vapor induced phase separation (VIPS) was used to fabricate flat-sheet membranes using a dope solution consisting of PMMA, PVDF, TiO2, and triethyl phosphate (TEP) as an alternative non-toxic solvent. Membrane morphology was examined by scanning electron microscopy (SEM). Backscatter electron detector (BSD) mapping was used to monitor the inter-dispersion of TiO2 in the membrane surface and matrix. The effects of polymer concentration, evaporation time, additives and catalyst amount on the membrane morphology and properties were investigated. Tests on photocatalytic degradation of methylene blue (MB) were also carried out using the membranes entrapped with different concentrations of TiO2. The results of this study showed that nearly 99% MB removal can be easily achieved by photocatalysis using TiO2 immobilized on the membrane matrix. Moreover, it was observed that the quantity of TiO2 plays a significant role in the dye removal.

The aim of this work is to study and evaluate in situ, the Artemisia herba alba responses to hexavalent chromium stress in the arid and semi-arid steppe Algerian soil. This metallic pollutant was selected to its high toxicity and to its great release from several industrial and agricultural activities emissions in the area of the study region. Artemisia herba alba is a medicinal plant but also a forage species widely used in pasture. It has dominated then adapted to the arid and semi-arid climate of Algerian steppe region, due principally to their morphological and physiological characteristics. To establish this work, A. herba alba species were selected in the Algerian steppe region, and their soils were treated weekly with K

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 work, the effectiveness and applicability of a physicochemical coagulation/flocculation process for the pretreatment of textile industry discharges containing Hydron Blue Dye using Al2(SO4)3 as destabilizing agent was studied. The coagulation/flocculation performance on the quality of treated water was measured by UV absorbance at different wavelengths, by scanning electron microscopy and Fourier transform infrared spectroscopy. Results showed that the process was effective with a maximum yield of 77% under optimized conditions of pH, coagulant dosage, concentration of initial solutions, and stirring speed. The optimization of this process by a design of experiments allowed us to construct models with an R2 value of 0.99 for the coagulation/flocculation in the chosen field.

Magnetic activated carbon composite (MAC) was successfully prepared from olive residues and hematite (Fe2O3/AC). MAC was prepared based on a wet impregnation method followed by carbonization, under different operating conditions. Specifically, two different MACs were prepared by altering the temperature ramp rate during the carbonization procedure (5 and 20 min/°C), designated here as MAC5 and MAC20, respectively. The increased magnetic capacity of the two MACs (as evidenced by the measured permanent magnetism of 30 mT), allowed their easy separation by utilizing a simple magnetic separation technology. The efficient impregnation of the iron oxide on the two MACs was confirmed by Fourier transform infrared spectroscopy (FT-IR), while scanning electron microscopy (SEM) was used to characterize the morphology of the composites. FT-IR measurements showed the appearance of new peaks, between 500 and 700 cm−1 which is evidence of the effective binding of iron onto AC (C/Fe). The SEM images offered an i...

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.

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...

The results of a feasibility study are presented on the use of a polystyrene (PS) organic membrane as a photocatalyst support in the degradation of organic pollutants in aqueous solution. Methylene blue (MB) was employed as a model dye and commercial titanium dioxide (TiO2) was used as a photocatalyst. The MB dye which is resistant to direct photolysis especially at high concentrations was successfully eliminated by TiO2 fixed on the PS membrane in aqueous dispersion under solar irradiation. Photodegradation results of MB showed that the film with 10 wt% TiO2 exhibited a remarkable ultraviolet (sun light) photocatalytic activity over 5 h, with 68% of the pollutant being degraded. This is similar to a TiO2 slurry system. The photocatalytic degradation obeyed pseudo-first-order kinetics at low initial MB concentration. The optimum pH for efficient removal of dye was found to be 11. An increase in initial dye concentration decreased the degradation rate. The applicability of Langmuir–Hinshelwood kine...

Nanometer sized and sheet-like bentonites play an important role in the removal of metal ions from contaminated water. They exist everywhere in nature and can develop a good and less expensive alternative in wastewater cleanup containing heavy metals. However, their use may generate turbid suspensions difficult to settle. Therefore, a coupling of adsorption on natural material was chosen. A modified Algerian bentonite in coagulation/flocculation processes was used with a biological flocculant obtained from waste recovery of fishery products. The results demonstrate that the modified bentonite has a very high adsorption capacity. The treatment efficiency was evaluated by measuring turbidity. The removal rate was observed around 99%.

The main purpose of the present study is to investigate the mechanism which governs the adsorption of the pesticide onto electro-granular activated carbon (GAC). The operating conditions assessed are: electrical potential, electro-activation time, the initial metribuzin—electro-activated GAC concentration ratio (R = Cp/CGAC). In the first step, it has been confirmed using an experimental design that the C/C0 ratio is much more affected by the electrochemical potential application than by R ratio. The mathematical model indicates that the electrochemical potential has a significant effect during the metribuzin adsorption during the first half an hour on GAC and thereby demonstrates the electroactivation beneficial effect. In the second step, a mass transfer model has been applied in order to evaluate the effect of the electro-activation of GAC on the kinetic constant. Indeed, the results showed that the electro-activation accelerates the process with kinetic constants 2–3 times higher than those ob...

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%.

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 new method for determining the electrical conductivity of ion-exchange membranes was implemented with four commercial membranes (AMX, CMX, MK-40 and MA-41). It is based on lateral resistance measurements without direct contact between electrodes and membranes. The cell configuration made it possible to determine the membrane conductivity over a wide range of electrolyte concentrations (measurements were carried out in the range 10 −5 –5×10 −1 M). The structural parameters of the different membranes were inferred from AC conductivities and the microheterogeneous model. They were found in good agreement with literature results obtained by normal measurements (i.e. with current lines oriented normally to the membrane surface), thus confirming the reliability of the proposed method. The main advantage of our method is the possibility to characterize ion-exchange membranes even at low salt concentration unlike usual non-contact methods based on normal measurements. Counterion diffusion coefficients and transport numbers within the membrane gel phase were estimated. The inter-gel phase volume fraction of an anion-exchange membrane (AMX) was also determined for the first time from membrane DC conductivity inferred from streaming potential and streaming current measurements. An excellent agreement was found with structural parameters obtained from AC measurements.

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 ).

The main purpose of this work is to study the ability of the enzymatic reaction. For the performance of the experiment, it is desirable to control variations so that they are minimized to the maximum extend and therefore an optimum operating point can be maintained. To achieve this target, the central composite design takes into account all interaction effects that may be useful for creating a mathematical model in agreement with the validity criteria. The model showed to be more suitable for the saccharification experiments in batch mode than in continuous mode. In batch mode, a correlation coefficient close to unity (R2 = .98) was obtained. Moreover, the resulting mathematical model was satisfactory in accordance with the validation criteria. For continuous mode, the coefficient value obtained was R2 = .83 indicating that the model to study the ability of the enzymatic reaction was inferior than the batch mode conditions of the analysis. Practical applications The ability of the enzymatic reaction to maintain its performance at small experimental condition variations was studied. The central composite design conformed to criterion validity. A correlation coefficient close to unity (R2 = .98) was obtained.

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.

Acclimated activated sludge was examined for its ability to degrade malathion with and without the presence of glucose as a potential cometabolite substrate. In this study, a packed-bed reactor (PBR) using three kinds of biofilm carriers was employed for efficient degradation of malathion. The results obtained indicate that microorganisms tested were able to degrade malathion. The observed degradation rate of the pesticide in the presence of glucose was the same as without glucose. The activated sludge was found to be able to use malathion as the sole phosphorus source. In contrast, the degradation ability of the activated sludge was lost when the pesticide was used as the sole source of sulfur. The degradation capacity of the PBR was higher than the performance obtained with the batch reactor. The reactor packed with crushed olive kernels exhibited the best performance, allowing a total removal of malathion (10 mg/dm3) within 12 h.

International audience; Chitin extraction by biological way, using the lactobacilli Lactobacillus helveticus, is a non-polluting method and offers the opportunity to preserve the exceptional qualities of chitin and its derivatives. However, the major disadvantage of the fermentative way is the low efficiency of demineralization and deproteinization. The aim of our study is to improve the yield of extraction. Many factors, such as the initial concentration of carbon source, fermentation time, incubation temperature, inoculum size, shell size, volume and medium composition have been reported to influence the fermentation process and consequently demineralization and deproteinization efficiency. Based on the use of central composite design and response surface methodology ten factors with three levels each were examined to determine the optimal operational conditions of demineralization and deproteinization. The analysis of the obtained results showed that the optimal conditions of 98% of demineralization and 78% of deproteinisation are 171.4 g L−1 of reducing sugars, 2.03 g of nitrogen source [(NH4)2Fe(SO4)2] and 1.29 g of calcium source (CaCl2), used to ferment 4.84 g of shells, of 1.053 mm size heat treated at 120 °C, with 10 mL of inoculum (L. helveticus) incubated at 32.1 °C in 100 mL of juice date for 254.38 h (15 days).

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.

International audience

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.

Olive oil production results in important quantities of wastewater containing large amounts of total solids and organic carbon as well as low oil concentrations. This paper describes the treatment of olive mill wastewater (OMW) by combining an ultrafiltration (UF) technique and an advanced oxidation process (AOP) using UV/H2O2. It further demonstrates the technical feasibility of this compact and stable process to remove a large part of total solids and organic carbon. Indeed, OF reduces the pollutants contained in the OMW with an apparent rejection coefficient RCOD in the range of 94%. The UV/H2O2 oxidation process may be easily used, in combination with UF, to finish the treatment of the permeate. The results obtained in batch and continuous mode showed that this technique offered a treated solution which complies with legal requirements. A final concentration of 17 mgTOC dm−3 was obtained, which corresponds to a final COD of 52 mg dm−3, while the legal requirement is 125. Furthermore, the final effluent is fully decolorized.

“Ecole Nationale Polytechnique dillger, B.P. 182-16200, El Harrach, Alger, Algeria “DPpartement GEnie chimique, University of Technology of Compiggne, B.P. 20.509, 60205 CompiGgne cedex, France Tel. +33 (3) 44 23 44 57; Fox: +33 (3) 44 23 52 16; email: nabil.mameri@utc.j? Received 15 November 2002; accepted 10 February 2003 Abstract A new activation technique using alumina was developed for the removal of fluoride from water. This technique is based on an electro-activation by means of an electrical field. The optimum activation parameters (potential and contact time) were determined, and an activation time of about 120 min and a potential of +lOO mV/SCE were then selected. The effect of various experimental parameters - ionic strength, pH hardness, and fluoride-alumina concentration ratio GGb- was determined for the adsorption capacities ofthe electro-activated alumina. The effect ofthese parameters on the fluoride adsorption capacities of both electro-activated adsorbent and conventional alumina was essentially the same, except for the ionic strength parameter. Indeed, ionic strength did not have a considerable effect on the performance of the conventional alumina. However, for the electro-activated alumina, an increase in ionic strength induced a slight increase in the fluoride adsorption capacity ofthe electro-activated adsorbent. The optimum conditions, determined in the batch mode, gave an optimal pH ranging from 3.5 to 5 and a C,,/C, ratio of about 4. At a NaCl concentration of 800 mg dm3, the fluoride adsorption capacity of the electro-activated alumina was about 55% better than that of conventional alumina. Keywordrs: Adsorbent activation; Electrochemical technique; Fluorine; Alumina

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 performance of biofiltration of zinc utilising pretreated Streptomyces rimosus was studied. Streptomyces rimosus biomass is able to bind zinc ions in batch mode. The biomass granules may be regenerated easily by using a biomass pretreatment which confers rigidity to biosolids, without decreasing the zinc uptake capacity, thus allowing collection of the biomass by filtration. Accordingly, biomass was pretreated with an anionic enzymatic tension active product (Extran AP41) and regeneration with a cleaning product (HCl) was successfully realised. It was shown that the optimum concentration of biomass and pressure range are found to be between 50 and 120 g dm−3 and 0.5 and 1 × 105 Pa, respectively. Complete regeneration was reached after three cycles under optimal experimental conditions when the biosorbent was saturated with synthetic ZnCl2 solution. The filterability of biosolids was demonstrated. A combination of a batch reactor and a filtration process made it possible to increase the performance of the complete treatment process. The biosorption capacity of the biomass to bind Zn ions was slightly increased (from X = 14 mg g−1 in batch mode to X = 16.1 mg g−1 in a process combining batch reactor and pressure filtration) and the experimental contact time was considerably reduced. Integration of the filtration process produced a dewatering cake which considerably facilitated the regeneration operation. Copyright © 2003 Society of Chemical Industry

This paper describes the enzymatic hydrolysis of haemoglobin in a continuous membrane bioreactor which was equipped with either a microfiltration membrane (Carbosep M14) with an average pore diameter of 0.14 μm or an ultrafiltration membrane (Carbosep M5) with 10 kDa molecular weight cut-off. These membranes gave similar performances indicating that the virgin porosity was modified by adsorption of proteins and enzymes, and by the formation of a dynamic membrane on the mineral membranes. Practically both membranes presented identical optimum parameters corresponding to an average transmembrane pressure of 1.25 bars and a tangential velocity of 0.7 m s−1. A simple theoretical kinetic model based on the Michaelis–Menten relation and the substrate mass balance was successfully used for the enzymatic hydrolysis of the haemoglobin in a continuous membrane bioreactor.

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 .

Olive oil production requires important quantities of washing water containing low oil concentrations, but classical processes used to recover or to eliminate this oil are ineffective. This study presents a membrane technique to treat olive oil mill washing water using different commercial ultrafiltration membranes: one organic (PCI) and two ceramic (Ceraver) membranes. The influence of the hydrodynamic parameters (transmembrane pressure and flow rate) and the cut-off membranes on the efficiency of the ultrafiltration process was evaluated, and it was shown the organic PCI membrane could reduce pollution due to organic matter by decreasing the value of the Chemical oxygen demand by about 90%. Moreover, the nature of the ultrafine pore membrane appeared to be an important parameter which may strongly increase or decrease the capacity of the membrane. The membrane cut-off did not have a strong influence on the performance of the process but if the membrane pores were too large the stability of the dynamically formed membrane decreased at transmembrane pressures greater than 0.2 MPa. La production d'huile d'olive requiert des quantites importantes d'eau de lavage contenant de faibles concentrations d'huile, mais les procedes classiques utilises pour recuperer ou eliminer cette huile sont inefficaces. On presente dans cette etude une technique membranaire pour le traitement de l'eau de lavage d'une unite de fabrication d'huile d'olive dans laquelle differentes membranes d'ultrafiltration commerciales sont employees: une membrane organique (PCI) et deux membranes de ceramique (Ceraver). L'influence des parametres hydrodynamiques (pression et debit transmembranaires) et de la distribution de taille des pores sur l'efficacite du procedee d'ultrafiltration a ete evaluee, et on montre que la membrane organique PCI pourrait reduire la pollution due a la matiere organique en diminuant la valeur de la demande chimique en oxygene d'environ 90%. Par ailleurs, la nature de la membrane a pores ultrafines semble un parametre important qui pourrait fortement augmenter ou diminuer la capacite de la membrane. La taille des pores n'exerce pas une grande influence sur la performance du procede mais si les pores de membrane sont larges, la stabilkite de la membrane formee de maniere dynamique diminue a des pressions transmembranaires superieures a 0,2 MPa.