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The objective of this study is to collect more data on the bio-monitoring of trace element pollution and the distribution of emission sources at the local scale. Accordingly, the concentrations of several trace elements (TEs) were measured in epiphytic lichens and tree bark samples collected from an area of study near Algiers-Algeria, using the instrumental neutron activation analysis (INAA) technique. The results show the existence of more than 20 TEs and the study of the enrichment factors (FEs) indicates pollution of anthropogenic origin: brickyard with emissions of Na, As, Se, Sc, Co, Cr, Tb, Ta, Fe, pollution of vehicles with emission of Se, Sb and Zn and re-suspension of the soil with emission of Zn and Br.

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.

Sewage treatment plants in Algeria produce huge quantities of sludge expressed in tons annually. This sludge produced is unfortunately contaminated because of the use of synthetic polyelectrolytes. Recently several kinds of research have been carried out on natural flocculants for sludge conditioning, because of several advantages they present such as their renewable source and their non-toxicity. This work aims to evaluate the potential use of protonated pectin extracted from orange waste of N'GAOUS juice factory as an eco-friendly flocculant in the chemical conditioning of sludge. Protonated pectin effectiveness was compared with synthetic cationic anionic and ionic polyelectrolytes (SUPERFLOC 8396, AF400, NF102). In this context, raw sludge samples from Bouira WWTP were tested. Specific resistance to filtration (SRF), cakes dry solid content were analyzed to determine filterability, dewatering capacity of conditioned sludge, and the optimum dose of each conditioner. So that our goal was to obtain greater dryness, which is the case with the addition of protonated pectin and even the addition of Superfloc, which allowed us to obtain dryness of 33.01% and 29.19%, respectively, for the same doses that gave the lowest SRF. Based on the results found and the analysis of the specific resistance to filtration (SRF) and the dryness, and compared with the values observed for the dewatered sludge by the method used in the Bouira WWTP. Band filters (18-22%) and raw sludge (4.8-5.7%).

Leptospira strains were isolated from freshwater sampled at four sites in Algeria and characterized by whole-genome sequencing and matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). The cells were spiral-shaped and motile. Phylogenetic and MALDI-TOF MS analyses showed that the strains can be clearly distinguished from the other described species in the genus Leptospir a, therefore representing two novel species of the pathogen subclade P1 and two novel species of the saprophyte subclade S1. The names Leptospira ainlahdjerensis sp. nov. (type strain 201903070T=KIT0297T=CIP111912T), Leptospira ainazelensis sp. nov. (201903071T=KIT0298T=CIP111913T), Leptospira abararensis sp. nov. (201903074T=KIT0299T=CIP111914T) and Leptospira chreensis (201903075T=KIT0300T=CIP111915T) are proposed.

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 photo-fermentative biohydrogen production using photosynthetic purple non-sulfur and non-oxygenic bacteria Rhodobacter sphaeroides is a very promising green technology. In this paper, several s...

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.

In the present work, solar energy conversion into electricity was evidenced by the Chlorophytum comosum-Microbial Fuel Cell (Chlorophytum-MFC). Our Chlorophytum-MFC had produced an Open Cir...

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 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.

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.

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...

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.

The present study is focused on the effect of chitin derivatives against human cancer cell lines RD and Hep2. As an outcome from this research, chitin was cytotoxic at IC50 = 400 μg/ml and 200 μg/ml against Hep2 cells and RD cells lines, respectively. Irradiated chitin had an IC50 value of 450 μg/ml for Hep2 and an IC50 of 200 μg/ml for RD. The lowest IC50 is attributed to chitosan, 300 μg/ml in Hep2 and 190 μg/ml in RD.

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

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%.

Four aqueous extracts of different plant organs are the following: Artemisia herba-alba, Opuntia ficus-indica, Camellia sinensis and Phlomis crinita were evaluated against two bacterial strains: Porphyromonas gingivalis and Prevotella intermedia, which are implicated in periodontal diseases. By using a disc method, these plant extracts demonstrated powerful bacterial activity against these Gram-negative strains. The minimum inhibitory concentration values of the four plant extracts varied between 0.03 and 590.82 mg/ml for the microbes. Another assay using commercial antibiotics and antibacterials as positive controls was also conducted. Values obtained after statistical analysis of inhibition diameters of all plant extracts demonstrated that for P. gingivalis, the aqueous extracts of A. herba-alba and O. ficus-indica were most effective, followed by those of C. sinensis and P. crinita. For P. intermedia, aqueous extracts of O. ficus-indica and C. sinensis appeared to be more efficient with significantly different (P > 0.05) inhibition diameters, followed by those of O. ficus-indica and P. crinita. In summary, the statistical results reveal that these plant extracts exert stronger antibacterial activity on P. intermedia germ as compared to P. gingivalis.

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 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...

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 main purpose of this study is the use of TiO2 as catalyst in thin film fixed bed reactor (TFBR) for the treatment of landfill water with the high initial concentration of recalcitrant organic matter. The effectiveness treatment process was determined by the evaluation of the influence of the experimental parameters such as the pH on the Chemical Oxygen Demand (COD) and NH4+ concentration. The experimental assays were performed by varying the pH value from 5 to 6. The results obtained after treatment using this process was relevant. Indeed, a decrease of about 92% of the COD was achieved at pH maintained at 5. Moreover, the value of the BOD5/COD ratio obtained indicated that the water obtained after treatment are favorable for biological treatment. However, the NH4+ concentration was not affected by this process and remained at its high value.

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.

Edible coatings as affected by chitosan extraction processes were used to preserve the quality of strawberries (Fragaria × ananssa) during their storage at ambient temperature (20–25 °C). Thus, three different chitosans were prepared from shrimp shell and were designated as the following: C1 by classical method, C2 without the decoloration step, and C3 without the decoloration step and the deproteinization step. In order to study the effectiveness of coatings, changes in physicochemical parameters and mold spoilage were studied. Chitosan coatings had no significant effects on titrable acidity, pH and soluble solids content (SSC) of strawberries throughout the storage, while the SSC content of control fruits increased with the storage time. In contrast, chitosan coatings delayed changes in weight loss and the appearance of fungal infection. Coated samples had greater visual acceptability than had the untreated fruits. By visual analysis, it was possible to verify that the best quality was maintained until the day 12, for the strawberries coated with C3 (1 %).

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 effect of coating tomato fruit (Lycopersicon esculentum) with shrimp shell chitosan, a deacetylated form of chitin, and a chitosan derivative, i.e. N,O-carboxymethyl chitosan (NOCC) on postharvest preservation was studied. The effects of various chitosan and NOCC concentrations on fruit ripening behavior, as well as fruit physical and chemical characteristics were evaluated during storage at room temperature (25–30 °C). Coating the fruit with 2 % (w/v) chitosan or NOCC solutions was found to be more effective in extended its storage life than coating with 0.5 % (w/v) solutions. Covered tomatoes were firmer, higher in titratable acidity, and exhibited less red pigmentation than the control uncoated fruits at the end of storage. These results suggest the suitability of chitosan and its derivative NOCC as an alternative means of preserving fresh fruits.

Boron removal in seawater desalination presents a particular challenge. In seawater reverse osmosis (SWRO) systems boron removal at low concentration (