Optimization of coagulation-flocculation process for pastas industry effluent using response surface methodology

The goal of this study was to characterize and then optimize the treatment process of effluent generated from couscous and pasta industry. The crude effluent is characterized by a high level of organic concentration (from 2269 to 4383 mg/l). The optimization of coagulation-flocculation process was then performed to minimize chemical oxygen demand (COD). The experiments were carried out using the response surface methodology (RSM). A central composite design (CCD) was used to evaluate the effects and the interactions of three factors; coagulant dosage, flocculant dosage and pH on the wastewater treatment efficiency. Quadratic models was developed for the response variables and it successfully describes the experimental data (R2= 0.728). Analysis of variance (ANOVA) showed that only the coefficients corresponding to the flocculant dosage were significant (p < 0.0001). In order to take into account the variability of the initial organic concentration of the effluent, the CCD was repeated thrice by using a wastewater having initially different organic charges (530, 1775 and 2722 mg/l). Whatever was the initial organic charge of the wastewater, the optimal coagulant dosage was found constant (about 50 mg/l) and the optimal pH value was about 11.0. On the contrary, the optimal flocculant dosage varied linearly (from 24 to 50 mg/l) with the initial COD (from 529 to 2722 mg/l). These optimal conditions allow a COD removal varying from 78 to 93%. Irrigation and germination tests were carried out with treated and untreated wastewater and they showed that these effluents could be adequately recycled in culture irrigation.Key words: Couscous and pasta industry effluent, COD removal, central composite design, response surface methodology (RSM), irrigation tests

Comparison between bubbling and turbulent regime for the simulation of batch pharmaceutical powders fluidized bed drying

[EN] The two-phase theory has been frequently used to model fluidised bed drying. At high air velocities, a transition from the bubbling regime to the turbulent regime may occur. In this work, we compare a bubbling model and a turbulent model for the simulation of a two pharmaceutical powders drying in a pilot plant and an industrial plant fluidised bed. The bubbling model was based on a discrete variable bubble size. Heat and mass transfer coefficients were based on the Kunii and Levenspiel correlation [1]. Flow regime was supposed to be completely mixed for the emulsion phase. For the turbulent model, the bubble size is not anymore discrete but continuous and bubble phase is less distinguishable than in the bubbling regime. Heat and mass transfer were those proposed by Foka[2]. In addition, the freeboard section was considered since high entrainment is specific of this regime. Gas backmixing was taken into account by considering a plug flow with axial dispersion for the interstitial gas flow. The bubble phase being dilute, was modeled by a plug flow. A plug flow was also considered for the freeboard gas. The solid phase was supposed to be completely mixed. The bubbling regime simulation gave good agreement with experiment in the case of the pilot plant experiment, while the turbulent model better simulated the industrial scale experiment.Zammouri, A.; Boudhrioua Mihoubi, N.; Kechaou, N. (2018). Comparison between bubbling and turbulent regime for the simulation of batch pharmaceutical powders fluidized bed drying. En IDS 2018. 21st International Drying Symposium Proceedings. Editorial Universitat Politècnica de València. 457-464. https://doi.org/10.4995/IDS2018.2018.7703OCS45746

Thermodynamic properties and moisture sorption isotherms of two pharmaceutical compounds

[EN] This investigation examines and compares the water sorption isotherms and the thermodynamic properties of two pharmaceutical preparations (Hypril and Azix) intended to be manufactured with the same process plant and equipment. The moisture equilibrium isotherms were determined at 50, 60 and 70 °C using a gravimetric technique. Five isotherm models were explored for their fitting to the experimental data. Azix showed sigmoid type II isotherms while Hypril showed type III isotherms according to the BET classification. All investigated models fitted well the water sorption isotherms of Hypril. By contrast, only GAB and Adam and Shove equations gave appropriate fit to the experimental data of Azix. For both formulations, the isosteric heat and the differential entropy decreased sharply with the increase of equilibrium moisture content to minimum values and thereafter remain constant. In the case of Azix, the integral enthalpy decreased with equilibrium moisture content while the integral entropy increased until reaching a constant value. Contrariwise, Hypril showed decreasing of the integral enthalpy and entropy with the equilibrium moisture content.Zammouri, A.; Ben Zid, M.; Kechaou, N.; Boudhrioua Mihoubi, N. (2018). Thermodynamic properties and moisture sorption isotherms of two pharmaceutical compounds. En IDS 2018. 21st International Drying Symposium Proceedings. Editorial Universitat Politècnica de València. 449-456. https://doi.org/10.4995/IDS2018.2018.7702OCS44945

Field Attractants for Pachnoda interrupta Selected by Means of GC-EAD and Single Sensillum Screening

The sorghum chafer, Pachnoda interrupta Olivier (Coleoptera: Scarabaeidae: Cetoniinae), is a key pest on sorghum, Sorghum bicolor (L.) Moench (Poaceae), in Ethiopia. At present there is a lack of efficient control methods. Trapping shows promise for reduction of the pest population, but would benefit from the development of attractive lures. To find attractants that could be used for control of P. interrupta, either by mass trapping or by monitoring as part of integrated pest management, we screened headspace collections of sorghum and the highly attractive weed Abutilon figarianum Webb (Malvaceae) for antennal activity using gas chromatograph-coupled electroantennographic detection (GC-EAD). Compounds active in GC-EAD were identified by combined gas chromatography and mass spectrometry (GC-MS). Field trapping suggested that attraction is governed by a few influential compounds, rather than specific odor blends. Synthetic sorghum and abutilon odor blends were attractive, but neither blend outperformed the previously tested attractants eugenol and methyl salicylate, of which the latter also was part of the abutilon blend. The strong influence of single compounds led us to search for novel attractive compounds, and to investigate the role of individual olfactory receptor neurons (ORNs) in the perception of kairomones. We screened the response characteristics of ORNs to 82 putative kairomones in single sensillum recordings (SSR), and found a number of key ligand candidates for specific classes of ORNs. Out of these key ligand candidates, six previously untested compounds were selected for field trapping trials: anethole, benzaldehyde, racemic 2,3-butanediol, isoamyl alcohol, methyl benzoate and methyl octanoate. The compounds were selected on the basis that they activated different classes of ORNs, thus allowing us to test potential kairomones that activate large non-overlapping populations of the peripheral olfactory system, while avoiding redundant multiple activations of the same ORN type. Field trapping results revealed that racemic 2,3-butanediol is a powerful novel attractant for P. interrupta

Etude de l’effet des conditions du séchage sur la texture et la couleur des filets de Sardina pilchardus

Le but de ce travail est d’étudier l’effet des conditions opératoires de séchage convectif par air chaud sur la couleur et la texture des filets de la sardine (Sardina pilchardus). Les filets de sardine ont été déshydratés par séchage convectif à vitesse d’air constante (Va = 1,5 m/s), différentes températures (40, 50 et 70°C) et à humidité relative d’air ambiante. Le critère final des expériences de séchage a été fixé de manière à avoir une teneur en eau finale des filets de l’ordre de 25% en base humide. La texture (mesure de la dureté par un texturomètre) et la couleur (paramètres L*a*b*) des filets ont été analysées à différents temps du séchage. L’évaluation des paramètres de qualité au cours du séchage (texture et couleur) montre que ces derniers dépendent de la teneur en eau du produit et des conditions de séchage. L’évaluation de latexture par le test de flexion trois points montre que l’augmentation de la température engendre une augmentation de la dureté des filets. Les paramètres L* et a* ont tendance à diminuer au fur et à mesure que la température de l’air augmente et la teneur en eau du produit chute. The aims of this work is the study of the effects of air drying process on the dehydration kinetics of sardine muscles (Sardina pilchardus).The effects of the air temperature (from 40 to 80°C) and the relative humidity (ambient and 40%) on the drying kinetics and on the color (L*a*b* parameters) and the textural (TAXT2i texturometer measurements)properties of the muscles were examined. Air drying kinetics were accelerated by increasing the air temperature and were attenuated by the humidification of drying air. The L* and a* parameters decreased with the increasing of air temperature. The injection of the moisture vapor on the air decreases this effect. The increasing of air temperature induced the hardness of the muscle and this effect was attenuated by moisture vapor’s injection. The moisture loss of the product induces a considerable decreasing of the muscle length

Estimation of moisture diffusivity in gelatin-starch gels using time-dependent concentration-distance curves at constant temperature

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Water desorption of osmotic dehydrated apple and pear at different water activities: desorption isotherms and glass transition temperature

Water desorption of osmotic dehydrated apple and pear at different water activities: desorption isotherms and glass transition temperature. Journée AFSI