KHALIDA Bekrentchir

ZEMMIRI Khadidja , LOUGHLITI Zeyneb

Simulation de l’écoulement et transfert thermique dans une cuve agitée a double enveloppe

SADOUKI Naima

Etude expérimentale du procédé d'électrocoagulation

DJEFFAL Sofiane

Étude du phénomène d'écrassement de l'échangeur EMD/MEA de la section de décarbonatation de complexe GL1/Z

Surface aerators are commonly used in activated sludge systems to supply oxygen needed for all aerobic bacterial process and also ensure sufficient mixing of the sludge suspension with wastewater. Power consumption by surface aerator is one of the significant design parameters for surface aeration tank reactor which is affected by the physical properties, operating parameters, and geometrical parameters. The knowledge of the power consumption is essential for the determination of overall rates of heat and mass transfer and circulating and mixing times and is directly, related to the operating cost. In this work, computational fluid dynamics (CFD) techniques were employed to study the effect of the surface aerator submergence depth ratio and rotation speed on power consumption in a full scale aeration tank equipped with a low speed surface aerator, model Landy-7. The multiple reference frames approach coupled with the volume of fluid model and k-ε turbulence model is applied to predict the flow induced by the surface aerator and the free surface motion. The simulation results were compared with experimental data reported in the literature. The CFD results show that, the maximum values of power consumption are achieved for the optimal submergence depth ratios which correspond to of 0 and 0.031 for N1=20 rpm and N2=33 rpm, respectively. This indicates that power consumption can be considered as a judgment criterion to determine the optimal surface aerator submergence depth ratio.

Citation

Khalida BEKRENTCHIR , ,(2023-12-20), Numerical optimization of power consumption in surface full-scale aeration tank,The first National Conference on Matter Sciences : NCSM2023 (Presential and online),Université de Djelfa

abattement de la pollution carbonée azotée et phosphate par un réacteur biologique à boue activée

Citation

Khalida BEKRENTCHIR , ,(2023-12-10), abattement de la pollution carbonée azotée et phosphate par un réacteur biologique à boue activée,2ÈME SÉMINAIRE NATIONAL ENVIRONNEMENT& GESTION DURABLE,Université de Relizane

Surface aeration tanks (SATs) are one of the main structures of activated sludge treatment process. The main functions of these bioreactors are to supply oxygen needed for all aerobic bacterial process and also ensure sufficient mixing of the sludge suspension with wastewater. This study presents a computational fluid dynamics (CFD) model of a full-scale SAT equipped with a low speed surface aerator, model Landy-7. The multiple reference frames approach coupled with the volume of fluid model and k-ε turbulence model is applied to predict the flow induced by the surface aerator and the free surface motion. After validation, the CFD model is used to optimize the submergence depth ratio of the aerator. Two different flow cases are observed depending on the aerator rotation speed. For low rotational speeds, the Landy-7 aerator acts as a surface aerator affecting mainly the water near the surface and has little effect on the shallow layers and the air-water interface is identified as the optimal position for the surface aerator. For high aerator rotation speeds, this effect persists longer in the SAT, even for large submersion depth ratios, which means that the Landy-7 aerator acts as an agitator as well as a surface aerator.

Citation

Khalida BEKRENTCHIR , ,(2023-12-02), Numerical simulation of submergence depth of surface aerator in full-scall aeration tank,the 1st national conference on physics and it's applications,Bousaada

Algeria is considered one of the hottest countries in the world due to the abundance of solar hours, especially in the south of the country. Therefore, the process of cooling homes and buildings is considered very important, but it is very expensive for the state. One of the solutions to reduce unwanted internal heat from buildings is to use solar energy. In this study, we used a solar chimney connected to a ground pipe to provide ventilation and cooling for a room in a house. Three different regions of the country were chosen: Algiers, M'Sila and Ouargla. To know the effect of climatic conditions on air flow in a room with limited dimensions. We simulated the air temperature distribution inside a room equipped with a solar chimney and connected to a ground pipe using the Fluent program. Finally, the percentage of energy consumption in the three regions mentioned above was discussed.

Citation

Khalida BEKRENTCHIR , ,(2023-12-02), Numerical study of energy consumption in a room in different climates. Case study: Algiers, M'sila and Ouargla.,THE 1ST NATIONAL CONFERENCE ON PHYSICS AND IT’S APPLICATIONS,Bousaada

The criteria for choosing a coagulant are numerous. Aluminum-based coagulants iron and even synthetic polymers have adverse effects on human health and the environment. Our goal is to look for a plant substituent. For this, we used the seeds of Moringa oleifera for the treatment of raw water from the WWTP of El Karma (Oran) by the coagulation/flocculation process in jar-test. The seeds were used in powder and solution at different concentrations. We optimized the pH parameter for different doses of bioflocculant. The stirring speed was maintained at 250 rpm for coagulation and 50 rpm for flocculation. The results obtained showed that the use of bioflocculant in solution is more effective than its use in powder. The pH optimization showed that at pH 7 turbidity decreases from 4096 NTU to 25 NTU. While at pH 5, turbidity decreases from 4096 NTU to 238 NTU. With the bioflocculant powder, the turbidity obtained is 218 NTU at pH 7 and 278 NTU at pH 5. Keywords – Moringa oleifera, Optimization, Bioflocculants, Raw water, Turbidity.

Citation

Khalida BEKRENTCHIR , ADMIN Admin , ,(2023-11-04), Effect of pH on raw water treatment at El-Karma WWTP (Oran),2nd International Conference on Contemporary Academic Research ICCAR 2023,Konya, Turke

This research is to incorporate three efficient ways that will increase the performance of baffled heat exchangers. The 1st technique is represented by baffle perforating to create pores through which secondary streams pass in order to reduce main stream pressure on the flow areas. A 2nd technique represented in redesigning the baffle structure by replacing its square edge with the arched edge in order to increase the X-velocity to facilitate the flow towards the outlet and reduce the Y-velocity to reduce the values of fluid friction with the solid areas. Finally, a 3rd way was demonstrated by using the inclined baffle model. Reinforcement of the baffle structure allowed for enhanced vortices, increased thermal gradients, and thus a reinforced thermodynamic structure over the entire heat exchanger

Citation

Khalida BEKRENTCHIR , , (2022-11-20), USING OBSTACLE PERFORATION, RECONFIGURATION, AND INCLINATION TECHNIQUES TO ENHANCE THE DYNAMIC AND THERMAL STRUCTURE OF A TOP-ENTRY CHANNEL, THERMAL SCIENCE, Vol:26, Issue:1, pages:10, VINCA INST NUCLEAR SCI

Domestic wastewater generated by human activities, especially household wastewater like; baths, washing machines, and kitchens; consists of large levels of pollutants (organic, inorganic and microbial) and that harm the natural environment and the health of human beings. Therefore, these wastewaters must be treated before discharging to avoid adverse effects in the receiving environment. In integrated modern township, domestic wastewater is treated separately, but in most of the places it is mixed with municipal wastewater and it is sent for treatment by means of physical, chemical, physico-chemical, or biological methods. Among physicochemical processes, electrocoagulation appears as an alternative technique due to their effectiveness in removing inorganic and organic contaminants from various types of wastewater with less energy consumption, its lower maintenance cost, less need for labor and rapid achievement of results. This technique is based on the electrochemical dissolution of sacrificial metal electrodes using just electric current and produce a coagulant species that destabilizes and traps pollutants in the form of suspended particles in wastewater, forcing them to form flocs and precipitate, resulting in the removal of pollutants. The iron, stainless steel, and aluminium electrodes are the most commonly used because of their low cost, easy availability, and proven efficiencies. In this work, treatment of a domestic wastewater by electrocoagulation process was investigated using a square section batch tank stirred with two blades impeller as a laboratory electrochemical reactor and aluminum electrodes. The samples were supplied from the wastewater treatment plant of ElKerma in Algeria. The main objectif of this study is to determine the effects of operational parameters on treatment performance, in order to evaluate the applicability of the process on real scale. Effects of various parameters such as electrolysis time (0–360 s), initial pH (5–10), current density (2–7 A/m2), and impeller rotational speed (1,67–3,33 s-1), were evaluated to find optimum operating condition for Total Suspended Solids and other pollutants removal. The experimental results revealed that the greatest removal efficiencies of the Total Suspended Solids and turbidity attained, respectively, 99.68, and 96.28% at the optimum conditions (operating time of 180 s, initial pH of 6, current density of 7 A/m2, and impeller rotational speed of 3,33 s-1). In addition, the bubbles generated from hydrogen at the cathode increase turbulence in the system and as a result, they improve the flotation separation process. This results shown considerably the technical feasibility of this electrochemical reactor design as a potential method for domestic wastewater treatment by electrocoagulation/flotation without the need of air injection and thereby, low operational costs.

Citation

Khalida BEKRENTCHIR , ,(2022-09-25), Optimization of electrocoagulation treatment of domestic wastewater using aluminium electrodes,First International Conference on Water and Environment ICWE’2022,Mascara, Algeria

This study presents a computational fluid dynamics (CFD) model of a full-scale surface aeration tank (SAT) equipped with a low speed surface aerator, model Landy-7. The multiple reference frames (MRF) approach coupled with the volume of fluid (VOF) model and k-ε turbulence model is applied to predict the turbulent flow induced by the surface aerator and the free surface motion. Simulations are performed for different rotational speeds and the predicted results in terms of steady-state power consumption are compared with literature data. After validation, the CFD model is used to study in detail the flow behavior in the SAT and then to optimize the submergence depth ratio of the surface aerator. Two different flow cases are observed depending on the aerator rotation speed. For low rotational speeds, the Landy-7 aerator acts as a surface aerator affecting mainly the water near the surface and has little effect on the shallow layers and the air-water interface is identified as the optimal position for the surface aerator. For aerator rotation speeds above 24 rpm, this effect persists longer in the SAT, even for large submersion depth ratios, which means that the Landy-7 aerator acts as an agitator as well as a surface aerator.

Citation

Khalida BEKRENTCHIR , , (2022-08-01), Numerical Investigation of Hydrodynamic in a Full-Scale Surface Aeration Tank, International Journal of Heat and, Vol:40, Issue:4, pages:927, INT INFORMATION & ENGINEERING TECHNOLOGY ASSOC

Surface aeration tanks are one of the main structures of wastewater treatment plants, especially in activated sludge treatment process. The main functions of the surface aeration tanks are to supply oxygen needed for all aerobic bacterial process and also ensure sufficient mixing of the sludge suspension with wastewater. Effective aeration in these bioreactors is achieved by placing a surface aerator close to the free surface of the liquid. The selection of a particular surface aerator is made according to consideration of efficiency of its oxygen transfer rate and its power consumption. Low-speed surface aerators are commonly used in activated sludge systems because they offer excellent oxygen transfer and mixing of the fluid, require little operational control, and able to handle environmental extremes such as high temperatures. In this study, the flow field in a full-scale square section tank fitted with a low speed surface aerator model Landy-7 developed and designed by WesTech and Landustrie is simulated using ANSYS Fluent software. This surface aeration tank is located at the wastewater treatment plant of El-Karma city in Algeria. The 3D k–ε turbulence model coupled with the multiple reference frames (MRF) approach were used to represent the particular flow induced by the Landy-7 surface aerator and the free surface deformation was modeled with the volume of fluid (VOF) method. After validating the numerical modeling of the surface aeration tank with the experimental measurements reported in the literature, the numerical tool is used to investigate the effects of surface aerator submergence depth on the main features of the flow field in the surface aeration tank, like volumetric power consumption, flow number rate, energy dissipation, shear rate, etc. Next, by solving numerical dispersion of a passive tracer, performance of the surface aeration tank is investigated in term of mixing time. The numerical results were presented for various rotation speeds and compared to predict the optimal submergence depth of surface aerator and to improve the energy efficiency of the wastewater treatment plants. Based on the simulation results of the flow field and mixing, an optimized operation scheme of the surface aeration was proposed.

Citation

Khalida BEKRENTCHIR , ,(2022-06-27), Numerical investigation of flow and mixing in a Full-Scale Surface Aeration Tank,First National Conference on Science &Technology (1st NCST22),Mascara, Algeria

As part of a comprehensive evaluation of post-treatment techniques for the removal of chemical and microbiological pollutants from lagoon effluents, an aerated biofilter was designed. The main objective of this study was to evaluate the performance of pozzolan and Luffa cylindrica as low-cost packing materials for the advanced treatment of Stidia natural lagoon effluent. The aerated biofilter operates in down-flow with HLRs of 11.37 to 28.43 m3 m−2 d−1 and an air/liquid flow ratio of 3 : 1. The different experiments performed on the pilot showed that the percentages of sCOD removal vary with the HLRs and the wastewater concentration at the biofilter inlet. In this study, sCOD removal efficiencies above 78.9 % were achieved depending on HLR, and a maximum removal efficiency of TSS of 71.5 % was obtained for 28.43 m3 m−2 d−1. At low HLR (11.37 m3 m−2 d−1), the treated effluent had the following average concentrations: sCOD of 29.5 mg l−1, BOD5 of 21.7 mg l−1 and TSS of 26.4 mg l−1. These experimental results were used with an empirical model to determine the media constant n and treatability factor K. The faecal coliforms and Escherichia coli detected in the treated effluent were less than 105 CFU/100 ml, which meet the national guidelines for wastewater reuse in irrigation.

Citation

ADMIN Admin , ADMIN Admin , ADMIN Admin , Khalida BEKRENTCHIR , ADMIN Admin , Malika Khellad, Meriem Abaidia, Senouci Boulerial, , (2022-05-27), Low-cost Packing Materials in an Aerated Biofilter for Lagoon Effluent Treatment, Kemija u Industriji-Journal of Chemists and Chemical Engineers, Vol:71, Issue:9, pages:8, HRVATSKO DRUSTVO KEMJIJSKIH INZENJERA I TEHNOLOGA

Elimination des Micropolluants des eaux usées destinées à l’Irrigation

Citation

Khalida BEKRENTCHIR , ,(2022-04-16), Elimination des Micropolluants des eaux usées destinées à l’Irrigation,1er Séminaire National sur Biodiversité, Biotechnologie et Développement Durable (BB & DD 2022),Université de Ghardaia

A numerical investigation of a scraped surface heat exchanger (SSHE) was undertaken, using the commercial CFD code FLUENT in order to characterize flow patterns and the shear rates. Regarding the operating conditions of the heat exchanger, Newtonian fluids and various geometric configurations were considered. A three-dimensional resolution of the continuity and momentum equations was conducted. After validation of the numerical strategy, a parametric study is made to better understanding the interactions between axial and rotation velocity. The simulation is achieved for various values of Taylor number for extended interval [0.09, 561.70] and axial Reynolds included [12, 2232]. Furthermore, the developed model has established the impact of the rotational speed and the mass flow rate on the shear rate.

Citation

Khalida BEKRENTCHIR , ,(2019-04-29), Numerical analysis of flow patterns and shear rates in a scraped surface heat exchanger,4th International Conference on Energy, Materials, Applied Energetics and Pollution - University of Constantine, Algeria-,University of Constantine, Algeria-

In this work, the mixing performance in a batch torus reactor was investigated using computational fluid dynamics (CFD). The two impellers applied in this study generated completely different flow patterns: one generates simultaneously axial and rotating motions and the other is particularly shaped for axial pumping.To validate the numerical model, the CFD results for the mean bulk velocity and power number were compared with the experimental data reported in the literature. Next, by solving the numerical dispersion of a passive tracer in an unsteady state, the performance of the torus reactor is investigated in terms of the mixing time. Finally, the numerical tool is used to study the effect of the system geometry and operating conditions on the power consumption and mixing energy. All investigations indicate that the classical three-blade marine impeller has the best mixing performances.

Citation

Khalida BEKRENTCHIR , , (2018-12-01), CFD Study of Mixing Characteristics in a Torus Reactor, In this work, the mixing performance in a batch torus reactor was investigated using computational fluid dynamics (CFD). The two impellers applied in this study generated completely different flow patterns: one generates simultaneously axial and rotating , Vol:4, Issue:1, pages:6, Salah Boubnider University of Constantine

Ultrasound assisted maceration was developed as a new and cleaner procedure for a green enrichment of an olive oil with rosemary essential oil. Ultrasound assisted maceration has been compared with conventional maceration. Ultrasound was then applied in order to accelerate diffusion of the rosemary volatile compounds into the olive oil. Then the enriched olive oil obtained by Ultrasound assisted maceration was qualitatively similar to those obtained by conventional maceration. However, the processing time is reduced from hours or days to few minutes when comparing traditional maceration and Ultrasound assisted maceration.

Citation

Khalida BEKRENTCHIR , , (2018-12-01), Optimization of ultrasound assisted extraction as enhanced method for maceration of olive oil with rosemary essential oil, Algerian Journal of Engineering Research, Vol:4, Issue:1, pages:2, Salah Boubnider University of Constantine

The effect of the impeller type on the flow behaviour in a torus reactor is evaluated using the commercial CFD code FLUENT. The two impellers applied in this study generated completely different flow patterns: one generates simultaneously axial and rotating motions and the other is particularly shaped for axial pumping. The evolution of the flow pattern along the reactor axis is investigated for different impeller rotation speeds, which shows the complex hydrodynamical interaction between the main rotating swirl motion involved by the impeller rotation and the bend curvature effects. Then, the effect of the particular flow generated by both impellers on the appearance of Dean vortices is investigated. The predicted results show different flow structures, which result from the evolution of the axial and the rotating motions when moving away from the impeller

Citation

Khalida BEKRENTCHIR , ,(2017-12-18), Effect of the impeller type on the flow pattern in a torus reactor,The 3rd International Conference on Mechanics and Energy - Sousse, TUNISIA-,- Sousse, TUNISIA-