Articles de revues : « Aeration efficiency »

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Azman, A., M. H. Zawawi, N. H. Hassan, A. Abas, N. A. Razak, A. Z. A. Mazlan et M. A. Z. Mohd Remy Rozainy. « Effect of Step Height On the Aeration Efficiency of Cascade Aerator System Using Particle Image Velocimetry ». MATEC Web of Conferences 217 (2018) : 04005. http://dx.doi.org/10.1051/matecconf/201821704005.

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Aeration is an important parameter in water filtration system as it allows the transfer of oxygen to water through turbulence effect which subsequently increases air entrainment in the water. For water treatment application, aeration efficiency is measured to ensure continuous re-oxygenation of the unfiltered water. Aside from aeration, this paper also studies the flow patterns through the use of particle image velocimetry (PIV) setup. Through the use of real scale down physical model laboratory study is performed using PIV to obtain the velocity profile. These velocity profiles will then be used to calculate the aeration efficiency of the water in a cascade aerator system. Based on the findings, the aeration efficiency obtained from the PIV experiment has a maximum value at the lowest point of the cascade aerator system with a value of 0.0139 due to increase in mass flow rate as it moves through the steps with velocity of 0.418 m/s. Therefore, in the design of a cascade aerator system, it is advisable to increase the number of steps since it will increase the aeration efficiency of the system.

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Deng, Feng, et Rui Zhang. « Research on COD Removal and SOUR of Aerobic Granule with Intermittent Aeration in Continuous Flow System ». Advanced Materials Research 518-523 (mai 2012) : 478–84. http://dx.doi.org/10.4028/www.scientific.net/amr.518-523.478.

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The impact of intermittent aeration on aerobic granular sludge in a continuous flow reactor was studied. Nine intermittent aeration modes were set up to investigate the change of DO, pH, COD removal efficiency and SOUR. The results showed DO and pH had different change tendencies. The 3-1 mode was the optimal mode under these experiment conditions. In aerating stage, the highest COD removal efficiency could achieve 96.32%. Stopping aeration for one hour, COD removal efficiency could still reach at 90.20%. This operation mode could save about 25% energy consumption theoretically. The comparison of SOUR between continuous aeration and 4-2 mode showed that the intermittent aeration had little effect on granular sludge activity. The theory of stress & damage and unbalanced growth could explain this appearance.

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Lindam, John. « Aeration Efficiency in Oxidation Ditches ». Proceedings of the Water Environment Federation 2013, n^o 3 (1 janvier 2013) : 387–400. http://dx.doi.org/10.2175/193864713813503413.

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Deka, Kuldeep, Dipika Bordoloi, Amar J. Khound, Manas J. Bharali et Racktackshree Chelleng. « A Review on Aeration Process and Different Types of Aerators Used in Various Aquaculture Systems ». International Journal of Current Microbiology and Applied Sciences 11, n^o 6 (10 juin 2022) : 353–58. http://dx.doi.org/10.20546/ijcmas.2022.1106.039.

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In any aquaculture plant maintaining dissolve oxygen (DO) level is essential for the better health and survival of the living organisms present in the water body specially fish. DO level can be maintained by aeration process. The general idea behind aeration is to bring the water into intimate contact with the air. Either the water may be discharged into free air or the air may be forced into water. Aeration process also removes light volatile organic compounds, dissolve gases and fix odor, taste etc. in case of drinking water. Some common Apparatus used includes: low cascades, multiple jet fountains throwing water to considerable heights, spray nozzles discharging above the surface of a reservoir, superimposed trays or shelves, submerged perforated pipes, and porous tubes and plates.There are two ways, standard oxygen transfer rate (SOTR) and standard aeration efficiency (SAE) of describing aerator performance. In selection of aerators for aeration in fish culture tank, durability and good standard aeration efficiency (SAE) value is too important moreover in case of aerators high standard oxygen transfer rate (SOTR) is important for the better growth of aquatic animals present in water. This article gives a review of different types of aerators used in aeration process based on various basis.

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Janssen, P. M. J., K. Meinema-Linders et R. P. Niermans. « Surface aeration and a small footprint can be combined ». Water Science and Technology 46, n^o 4-5 (1 août 2002) : 309–16. http://dx.doi.org/10.2166/wst.2002.0613.

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In densely populated areas new WWTPs will need to be designed on a relatively small area. This paper describes a deep Carrousel© (oxidation ditch) concept resulting in a “small footprint” for the aeration basin combined with an efficient and flexible oxygen input. To enable surface aeration in a deep Carrousel system, the basin was provided with so-called draft tubes, vertical cylinders located underneath aerators, almost extending down to the bottom. A draft tube enables the aerator to draw sludge/water mixture from the bottom of the tank, thereby ensuring proper oxygenation of the tank contents over the entire tank depth. The results of pilot-scale tests for verification of the performance of an aerator equipped with a draft tube are presented. The full scale WWTP Leidsche Rijn, a compact “wrapped-around” Carrousel-3000 system where the draft tube technology is applied in a 7.5 metre deep basin, is described. Before the plant was put into operation a verification test for the aeration efficiency with clean water was carried out. The test showed that the draft tubes have no negative impact on the aeration efficiency of the surface aerators and justified the chosen design concept.

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Ozkan, Fahri, M. Cihat Tuna, Ahmet Baylar et Mualla Ozturk. « Optimum air-demand ratio for maximum aeration efficiency in high-head gated circular conduits ». Water Science and Technology 70, n^o 5 (3 juillet 2014) : 871–77. http://dx.doi.org/10.2166/wst.2014.305.

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Oxygen is an important component of water quality and its ability to sustain life. Water aeration is the process of introducing air into a body of water to increase its oxygen saturation. Water aeration can be accomplished in a variety of ways, for instance, closed-conduit aeration. High-speed flow in a closed conduit involves air-water mixture flow. The air flow results from the subatmospheric pressure downstream of the gate. The air entrained by the high-speed flow is supplied by the air vent. The air entrained into the flow in the form of a large number of bubbles accelerates oxygen transfer and hence also increases aeration efficiency. In the present work, the optimum air-demand ratio for maximum aeration efficiency in high-head gated circular conduits was studied experimentally. Results showed that aeration efficiency increased with the air-demand ratio to a certain point and then aeration efficiency did not change with a further increase of the air-demand ratio. Thus, there was an optimum value for the air-demand ratio, depending on the Froude number, which provides maximum aeration efficiency. Furthermore, a design formula for aeration efficiency was presented relating aeration efficiency to the air-demand ratio and Froude number.

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Sukadana, Ida Bagus Putu, I. Made Rajendra, Ida Ayu Anom Arsani et I. Wayan Suastawa. « PERFORMANCE ANALYSIS OF 4-OUTLETS SPRAY AERATOR FOR PROCESSING OF INDIGOFERA LEAVES (Indigofera Tinctoria Linn) BECOMES NATURAL DYE SUBSTANCES ». Jurnal Bahan Alam Terbarukan 6, n^o 2 (24 octobre 2017) : 76–86. http://dx.doi.org/10.15294/jbat.v6i2.8045.

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The commonly known natural dye substance processing for traditional clothes, such as batik and tenun (woven cloth) is fermentation. The fermentation process can specifically be continued with extraction to produce indigo paste. The process can be done mechanically, i.e. by stirring process, and chemically. In order to accelerate the production, manual process of aeration can be substituted with jet-spray aerator. The aerator prototype which has been developed is acrylic aerator tube with diameter of 240 mm and thickness of 5 mm. The tube was made 1 m long to provide with a sufficient space for indigo foam. Its bottom part is completed with spiral air hose having five small holes of 0.2, 0.4, and 0.6 mm diameter uniformly located along the height of solution in the tube. The aerator was designed for the 10 litters of fermentation solution of 1 kilogram indigofera leaves. Based on the mass of indigo paste produced, the optimum working condition of the aerator is achieved on 3.8 m/sec air velocity and supply pressure of 2 bar with duration of 60 minutes. The aeration test indicated operational characteristic was quite good, i.e. Oxygen Transfer Rate (OTR) of 3.6 kg/hour, Aeration Efficiency (AE) of 4.8 kg/kWh and factual Oxygen Transfer Efficiency (OTE) of 44%.

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Kasakura, Tadao, Yoshiho Tomita, Kiwamu Matsubara et Atsushi Kubo. « A Basic Study of the Efficiency of Spiral Flow Aeration ». Water Science and Technology 23, n^o 10-12 (1 mai 1991) : 1951–60. http://dx.doi.org/10.2166/wst.1991.0651.

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The oxygen transfer efficiency of spiral flow aeration is affected by many factors, for example, the shape of aeration tank, the type of diffuser, the air flow rate and so on. The authors tried to determine the relationship between these factors and the efficiency of aeration. We found these factors were restricted by some independent variables, so we analyzed quantitatively the relationship between these variables and the efficiency of aeration based on data from the full scale experiments on spiral flow aeration using porous ceramic diffusers. Regression equations show that the efficiency of the spiral flow aeration would be higher with a reduction of the air feed rate per tank volume and an increase of the total bubbling area of the diffusers. Other variables would not so greatly affect efficiency.

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E. Khalaf, Anfal, et Mohammed A. Rashid. « PERFORMANCE EVALUATION OF LOCALLY FABRICATED MECHANICAL SURFACE AERATOR ». Journal of Engineering and Sustainable Development 25, Special (20 septembre 2021) : 3–213. http://dx.doi.org/10.31272/jeasd.conf.2.3.21.

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Experimental analysis for a fabricated Low-Speed surface aerator that can be used in wastewater and water treatment is presented in this research. The designed impeller configuration was tested to determine its power consumption, standard oxygen transfer rate (SOTR), and standard aeration efficiency (SAE). Impeller oxygen transfer and power consumption in a scaled laboratory tank were measured during aeration phase. The impeller was consisting of 8 inclines flat blades with an angle of 45° from center of the disc, was operated at 3 different immersion depths and 5 different rotational speeds for examining the impact of such factors on impeller efficiency. The results recorded that the best standard aeration efficiency for this configuration is (0.206 Kg. O2/KW.hr) at 120rpm and 7cm depth of the submersion, i.e. submersion depth to impeller diameter (h/D) ratio equals 0.175. Submergence depth increase beyond this limit would result in SAE decrease and definitely result into more power consumption.

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Cihat Tuna, M., Fahri Ozkan et Ahmet Baylar. « Experimental investigations of aeration efficiency in high-head gated circular conduits ». Water Science and Technology 69, n^o 6 (20 janvier 2014) : 1275–81. http://dx.doi.org/10.2166/wst.2014.021.

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The primary purpose of water aeration is to increase the oxygen saturation of the water. This can be achieved by using hydraulic structures because of substantial air bubble entrainment at these structures. Closed conduit aeration is a particular instance of this. While there has been a great deal of research on air-demand ratio within closed conduit, very little research has specifically addressed aeration efficiency of closed conduit. In the present work an experimental study was conducted to investigate the aeration efficiency of high-head gated circular conduits. Results showed that high-head gated circular conduits were effective for oxygen transfer. The effects of Froude number and ratio of the water cross-sectional flow area to the conduit cross-sectional area on aeration efficiency were particularly significant, whereas the effect of conduit length was only moderate. Further, a design formula for the aeration efficiency was presented relating the aeration efficiency to ratio of water cross-sectional flow area to conduit cross-sectional area and Froude number. The obtained results will be useful in future modeling processes and aid the practicing engineer in predicting aeration efficiency for design purposes.

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J. Zhu, C. F. Miller, C. Dong, X. Wu, L. Wang et S. Mukhtar. « Aerator Module Development Using Venturi Air Injectors to Improve Aeration Efficiency ». Applied Engineering in Agriculture 23, n^o 5 (2007) : 661–67. http://dx.doi.org/10.13031/2013.23667.

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Rous, Vít, Jan Vymazal et Tereza Hnátková. « Treatment wetlands aeration efficiency : A review ». Ecological Engineering 136 (octobre 2019) : 62–67. http://dx.doi.org/10.1016/j.ecoleng.2019.06.006.

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Roy, Subha M., Sanjib Moulick et Chanchal Kumar Mukherjee. « Design characteristics of perforated pooled circular stepped cascade (PPCSC) aeration system ». Water Supply 20, n^o 5 (4 mai 2020) : 1692–705. http://dx.doi.org/10.2166/ws.2020.078.

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Abstract In the present study, an improvised design over circular stepped cascade (CSC) and pooled circular stepped cascade (PCSC) aerator, named the perforated pooled circular stepped cascade (PPCSC) aerator, has been conceptualized and tested for its suitability as an aerator for small intensive aquaculture ponds. Based on dimensional analysis, dimensionless geometric parameters – ratio of width of consecutive steps (Wi/Wi+1) and ratio of perforation diameter to bottom-most radius (d/Rb) and dimensionless dynamic parameters – Froude (Fr) and Reynolds (Re) number were proposed. Initially, aeration experiments were conducted to optimize the geometric parameters, keeping the dynamic parameters constant. Keeping the optimized values of Wi/Wi+1 = 1.05 and d/Rb = 0.0027 as constants, aeration experiments were further conducted at different discharges (Q) and different bottommost radius (Rb) to study the characteristics of oxygen transfer and power consumption of PPCSC aerator at different dynamic conditions. Based on the optimized results, four prototype PPCSC aerators with Rb = 0.75 m, 0.90 m, 1.05 m and 1.20 m were fabricated for their aeration performances. The results showed that the standard aeration efficiency (SAE) values of the prototype PPCSC aerators based on brake power ranged between 3.36 and 4.98 kg O2/kWh, with the average being 4.45 ± 0.741 kg O2/kWh. This shows that the SAE of the PPCSC aerator is many more folds higher than that of the other available cascade aerators, viz., PCSC (SAE: 2.873 ± 0.342 kg O2/kWh) and CSC (2.470 ± 0.256 kg O2/kWh) aerators. The study clearly indicates that this PPCSC aerator may very well be used as pre-aeration or post-aeration units in water or wastewater treatment plants and small-scale intensive aquacultural ponds, replacing the other existing aerators.

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Ozkan, Fahri, Ibrahim Halil Demirel, Muhammed Cihat Tuna et Ahmet Baylar. « The effect of length of free-surface gated circular conduit on air-demand ratio and aeration efficiency ». Water Supply 15, n^o 6 (13 juin 2015) : 1187–92. http://dx.doi.org/10.2166/ws.2015.081.

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Aeration is the process of bringing water and air into close contact in order to increase dissolved oxygen concentration. The concentration of dissolved oxygen is an important indicator of water quality because aquatic life lives on the dissolved oxygen in the water. The hydraulic structures can be accepted as the key components in increasing dissolved oxygen concentration because of the strong turbulent mixing associated with substantial air bubble entrainment at these structures. Closed conduit is a classic example of a hydraulic structure where aeration occurs. This work focused on determining the effect of conduit length on air-demand ratio and aeration efficiency in free-surface gated circular conduits. Experimental results showed that the Froude number had an important effect on the air-demand ratio and the aeration efficiency. The effect of the conduit length on the air-demand ratio and the aeration efficiency changed depending on the Froude number. It was demonstrated from the results that a free-surface gated circular conduit flow system had high efficiency in transferring oxygen from air bubbles to water. Moreover, a formula for the aeration efficiency was presented relating the aeration efficiency to the conduit length and the Froude number.

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Rosso, Diego, Lory E. Larson et Michael K. Stenstrom. « Aeration of large-scale municipal wastewater treatment plants : state of the art ». Water Science and Technology 57, n^o 7 (1 avril 2008) : 973–78. http://dx.doi.org/10.2166/wst.2008.218.

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Aeration is the most energy-intensive operation in wastewater treatment, amounting to 45–75% of plant energy costs. Fine-pore diffusers are today almost ubiquitous in municipal wastewater aeration, due to their advantageous aeration efficiency (mass of oxygen transferred per unit energy required). Nevertheless, older municipal treatment facilities and many industrial treatment plants are still equipped with coarse-bubble or surface aerators. Fine-pore diffusers are subject to two major disadvantages: a) fouling, if not cleaned periodically; b) decrease in oxygen transfer efficiency caused by dissolved surfactants. Coarse-bubble and surface aerators are typically not subject to the traditional problems affecting fine-pore diffusers. Nonetheless, they achieve oxygen transfer at the expense of increased energy intensity. The increased biomass concentration associated with high mean cell retention time (MCRT) operations has a beneficial effect on aeration. Nutrient-removing selectors are able to further increase aeration efficiency, as they sorb and utilize the readily available substrate which otherwise would accumulate at bubble surfaces and dramatically decrease aeration efficiency. We summarise here our 30-year long experience in aeration research, and results obtained with clean- and process-water tests are used to show the beneficial effects of high MCRT operations, the beneficial effect of selectors, and the decline of aeration efficiency due to dissolved surfactants.

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Thomas, V. K., B. Chambers et W. Dunn. « Optimisation of Aeration Efficiency : A Design Procedure for Secondary Treatment Using a Hybrid Aeration System ». Water Science and Technology 21, n^o 10-11 (1 octobre 1989) : 1403–19. http://dx.doi.org/10.2166/wst.1989.0337.

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The fine-bubble diffused air (FBDA) system of aeration is most efficiently operated in low rate activated sludge systems. The aeration technique is, however, subject to poor oxygen transfer efficiency and diffuser clogging under increased loading conditions such as are experienced close to the tank inlet in plug-flow systems. Mechanical, surface aeration systems, though apparently less efficient, do not suffer from these disadvantages. The ideal aeration tank configuration, for optimum aeration efficiency is therefore:–inlet anoxic zone–completely mixed surface aerated zone–plug-flow, fine-bubble diffused air zone with tapered aeration–clarification tanks. An overall aeration efficiency of 1.5-2.0 kg/kwh is predicted for nitrifying systems, together with an increased diffuser lifetime compared to a conventional FBDA tank. The design procedure is illustrated using parameters for a large UK works. Despite greater civil costs, the reduced running costs and NPC of the hybrid system make it an attractive option when compared to a plug-flow FBDA system or a conventional surface aeration plant.

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Kokunova, Irina V., Alexander A. Zhukov et Tatyana E. Fyodorova-Semyonova. « INCREASING EFFICIENCY OF SOIL BIOREMEDIATION ». Siberian Journal of Life Sciences and Agriculture 14, n^o 4 (30 août 2022) : 215–27. http://dx.doi.org/10.12731/2658-6649-2022-14-4-215-227.

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The intensification of agricultural production and processing industries, the use of powerful tractors and harvesters, and the increase in the intensity of road cargo transportation lead to an increase in waste from economic activities and an increase in the anthropogenic load on the environment. Human-made accidents exacerbate the problems of the stability of natural ecosystems. Dangerous substances get into the soil and accumulate in it in the form of various toxicants. This situation poses a threat to all living organisms. One of the ways to solve the urgent problems of environmental safety and the production of high-quality agricultural products is the use of bioremediation technologies for soil purification. The paper aims to increase the efficiency of soil bioremediation technology by improving the technical means used for the aeration of soil piles. The current aerators-mixers perform soil agitation and grinding of large soil formations while saturating the treated material with oxygen. We propose improving the stirring drum design of a semi-suspended aerator-mixer, equipping it with new knife-shaped working blades and with a screw winding that allows increasing the contact area with the processed mass and forming a pile of a given shape. The contact surface increases due to biological products sprayed by the nozzles and the fine soil fraction formed after treatment. This fact also intensifies the microbiological processes of toxicant oxidation. Based on the theoretical research and multivariate regression analysis, we obtained a regression equation. It allowed us to establish the relationship between the main factors that affect the aeration process of soil piles to a greater extent. We carried out experimental studies in the scientific laboratories of the university. Thus, we determined the rational parameters of the improved aerator-mixer of piles.

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Šnīders, A. « Transient Process Modelling in Waste Water Aeration Unit ». Environment. Technology. Resources. Proceedings of the International Scientific and Practical Conference 1 (26 juin 2006) : 269. http://dx.doi.org/10.17770/etr2003vol1.2017.

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To minimize the expenditure of electrical energy for communal waste water biological treatment the simulation and investigation of oxygen transfer efficiency in aeration tank have been made. Soluted oxygen transfer efficiency ? 0 (Fig.1.) is one of the main important factor directly estimating the expenditure of electrical power for waste water aeration. The research object is an aeration tank (Fig.2.) with one input impact -–the air blower’s capacity Lg (m3/h), one output controlled parameter – dissoved oxygen concentration C (g/m3) and several perturbances such as waste water temperature T (oC), waste water afflux Q (m3/h) and biological oxygen need La (g/m3) for complete purification. Oxygen’s transfer efficiency depends on the waste water temperature, the depth of aerator immersion h (m), air flow intensity ? d (m3/disc.h) and the air diffusor’s density ? s. For simulation and practical design of the air blower control system the equations of statics C=f(Lg, Q, La, T, h, ? d , ? s) and dynamics C=f(t) have been compiled. That made possible to estimate the static gains for control channel Ka and for perturbances Kq, KT as well as the time constant of the aeration tank Ta. The analysis prove that the aeration tank is a non-stationary control object with the variable static and dynamic parameters and needs adaptive controller with predication of oxygen consumption. The block diagram for transient process simulation of the oxygen concentration control system have been compiled using model of the actual PID controller and the “Matlab” subprogram “Simulink”.

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Zhang, Sheng Yu, Chen Lv, Qing Ling Meng, Meng Yi Sun et Jian Song Xu. « Influence Factors of Remediation of Benzene in Groundwater by Air Sparging ». Advanced Materials Research 610-613 (décembre 2012) : 1662–66. http://dx.doi.org/10.4028/www.scientific.net/amr.610-613.1662.

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Medium sand was selected as simulation medium. Benzene was chosen as the target pollutant. Soil column simulation experiments were carried out to investigate the effects of influencing factors such as aeration rate, medium permeability and air injection mode on benzene removal efficiency in groundwater. The results showed that the aeration rate and medium permeability affected AS remediation efficiency significantly. The benzene removal efficiency increased with the aeration rate. When the aeration rate exceeded 300 mL•min-1, the removal efficiency did not increase any more. The bigger the hydraulic conductivity was, the higher removal efficiency of benzene was. In the same operation condition, pulsed intermittent air injection had advantages over continuous air injection for benzene •remediation in the medium sand with low hydraulic conductivity.

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Chu, Kejian, Zulin Hua et Lijun Ji. « AERATION AT OVERFLOW DAMS WITH CURVED SURFACES BY DIFFERENT FLASHBOARD SPILLWAYS ». JOURNAL OF ENVIRONMENTAL ENGINEERING AND LANDSCAPE MANAGEMENT 22, n^o 3 (11 août 2014) : 226–36. http://dx.doi.org/10.3846/16486897.2014.901226.

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Aeration using overflow dams is an eco-friendly and economical method of improving dissolved oxygen levels in polluted urban streams. Laboratory investigations of aeration performance in smooth spillways, as well as in parallel flashboard and interlaced flashboard spillways with different flashboard intervals, for overflow dams with curved surfaces have been conducted separately. Aeration efficiencies of the different types of spillways, in particular the effects of varying discharge rate, total spillway height, and flashboard interval, have been discussed in detail. The test data illustrate that aeration efficiency in all spillways increases with spillway height and decreases with increasing discharge. Flashboard spillways appear to provide significantly higher aeration efficiency than smooth ones, and aeration efficiency increases with the number of flashboards, but with a continuously declining growth rate. By combining Fds with hd*, a new dimensionless parameter Ψ is created to characterize the comprehensive effects of hydraulic conditions on aeration. Empirical formulas for oxygen-transfer efficiency in smooth, parallel flashboard, and interlaced flashboard spillways have been developed with Ψ and the dimensionless number of flashboards per unit area of spillway N* as independent variables, and the properties of these formulas are discussed.

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Ognean, T. « A New Dimensionless Criterion for the Oxygen Transfer Efficiency in Both Surface and Subsurface Aeration Systems ». Water Science and Technology 26, n^o 9-11 (1 novembre 1992) : 2531–34. http://dx.doi.org/10.2166/wst.1992.0780.

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The effect of power consumption on oxygen transfer efficiency has been evaluated in both surface and subsurface aeration systems. For this purpose a new dimensionless number To, named “efficiency criterion”, has been proposed.Using this number, the efficiency of different aeration systems could be compared.The comparison has been achieved by taking into consideration the data furnished by full-scale experimental models.The results have proved that of two aerators with identical diameters and the same rotational velocity reaching the maximum To, the one with a higher power consumption had a higher efficiency.The results regarding the subsurface aeration systems show that the efficiency of aeration equipment can be continuously increased if the bubbles' diameters are decreased.

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Zhu, H., T. Imai, K. Tani, M. Ukita, M. Sekine, T. Higuchi et Z. Zhang. « Improvement of oxygen transfer efficiency in aerated ponds using liquid-film-assisted approach ». Water Science and Technology 55, n^o 11 (1 juin 2007) : 183–91. http://dx.doi.org/10.2166/wst.2007.353.

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In aerated ponds, oxygen is generally supplied through either diffused or mechanical aeration means. Surface transfer and bubble transfer both contribute significantly to oxygen transfer in a diffused aeration system. In the present study, a liquid-film-forming apparatus (LFFA) is successfully developed on a laboratory scale to improve considerably the surface transfer via the unique liquid film transfer technique. The experimental results show that the volumetric mass transfer coefficient for LFFA alone is found to be as much as 5.3 times higher than that for water surface and that the total volumetric mass transfer coefficient for the liquid film aeration system increases by 37% in comparison with a conventional aeration system. Additionally, by tuning finely the structural parameters of the LFFA, it can also lead to high dissolved oxygen (DO) water with the DO percent saturation greater than 90%. More importantly, this result is accomplished by simply offering a single-pass aeration at a depth as shallow as 26 cm. As a result, the objective of economical energy consumption in aerated ponds can be realized by lowering the aeration depth without sacrificing the aeration efficiency. It is noteworthy that the data presented in this study are acquired either numerically or experimentally.

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Khalifa, A., S. Bayoumi et O. El Monayeri. « Mathematical modeling of aeration efficiency and dissolved oxygen provided by stepped cascade aeration ». Water Science and Technology 63, n^o 1 (1 janvier 2011) : 1–9. http://dx.doi.org/10.2166/wst.2011.001.

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Mathematical modeling has been a vital tool in the field of environmental engineering. Various models have been developed to simulate the level of aeration efficiency (AE) provided by different aerating structures to raise levels of dissolved oxygen (DO) in streams; one of which is the stepped cascade structure. Three models developed by Gameson et al. WRL, and Nakasone, in addition to Qual2k, a computer program for stream modeling, have been used in this research; values of AEs obtained have been compared to those computed using DO measured from a built model at a WWTP. A stepped cascade structure was installed with different heights to aerate five flowrates with different levels of COD. An adjustment has been made to the Nakasone model to test the effect of pollutant load on the amount of aeration that could be reached. Values of AEs computed using the Gameson model were 30%, 39.5%, and 40% for cascade heights (Hd) 45, 60, and 75 cm respectively for the five flowrates (q) that ranged from 21–66 m3/hr. Values of AEs from WRL model were 32.8%, 42%, and 43% consequently. Values of AEs from Nakasone model ranged from 4.6–7.5%, 6–10%, and 7.6–12% respectively. For the adjusted Nakasone model, values of AEs ranged from 3.2–4.9%, 3.3–5.3%, and 4.1–6.7% respectively. Finally, the AEs computed using the values of downstream DO generated by Qual2k ranged from 4–18%, 2–15%, and 2.5–5.1% correspondingly. Around 80% of the downstream DO values computed using the Nakasone and adjusted Nakasone model were closer to those measured in the field, thus more reliable in cascade design.

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Kujawiak, Sebastian, Małgorzata Makowska et Jakub Mazurkiewicz. « The Effect of Hydraulic Conditions in Barbotage Reactors on Aeration Efficiency ». Water 12, n^o 3 (6 mars 2020) : 724. http://dx.doi.org/10.3390/w12030724.

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Barbotage reactors such as airlift reactors (ALR) and bubble column reactors (BCR), due to their two-phase flow systems, were investigated in many research papers. In their basic design variants, they are typically used to lift, mix, and aerate liquids, while, when equipped with additional elements in hybrid variants, their individual properties, i.e., lifting, mixing, and aeration of liquids, can significantly change with the same reactor geometry. The object of this study was to develop a hybrid barbotage reactor in various structural design variants. The structure consisted of a barbotage column of 50 mm in diameter, used to transport a water–air mixture outside the reactor (so-called external loop). The installation was additionally equipped with a nozzle in order to improve mixture aeration and circulation efficiency. The nozzle was mounted at various heights of the column pump segment. Additionally, the reactor was equipped with s moving bed in two variants (20% and 40% reactor capacity) in order to determine its effect on the mixture aeration and circulation conditions. Based on the measurement results, aeration curves were prepared for various structural design and column packing variants of the reactor. Properties of the two-phase mixture were determined for both parts—ALR and BCR. Technological and energy parameters of the aeration process were calculated, and the results obtained for the individual structural design variants were compared. It was found that, for the most advantageous design, in terms of aeration efficiency, the aeration nozzle should be placed in the mid-length of the pump segment of the barbotage column, irrespective of the hybrid reactor packing rate with the moving bed. The reactor packing with the moving bed resulted in a decreased mean water velocity in the reactor. For most analyzed structural design variants, the respective packing with the moving bed had no significant effect on aeration efficiency. Only for one structural design variant did the lack of packing significantly improve oxygen levels by as much as approximately 41%.

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Li, Guo Chao, Jie Chen, Sheng Lu Yu, Tao Yang et Jian Qi Sun. « The Treatment of Synthetic Organic Wastewater in a Novel Internal Circulation Impinging Stream Biofilm Reactor ». Advanced Materials Research 281 (juillet 2011) : 30–34. http://dx.doi.org/10.4028/www.scientific.net/amr.281.30.

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An Internal Circulation Impinging Stream Biofilm Reactor (ICISBR) was developed and used for treatment synthetic organic wastewater with corncob as biofilm carriers. Effects of COD loading rates and aeration rates on COD removal and DO contents were investigated. COD removal efficiency increased together with effluent COD with increasing COD loading rates. As the aeration rate was increased, the DO content also increased together with COD removal efficiency up to an optimum aeration rate of 0.3m3h-1. Beyond this optimum aeration rate a significant decrease in DO content and COD removal efficiency were experienced. This study could provide theoretic basis for the ICISBR treating organic wastewater.

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Dong, C., J. Zhu et C. F. Miller. « Evaluation of six aerator modules built on venturi air injectors using clean water test ». Water Science and Technology 60, n^o 5 (1 mai 2009) : 1353–59. http://dx.doi.org/10.2166/wst.2009.420.

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Six aerator modules constructed using venturi air injectors connected in either series or parallel were evaluated and compared for their oxygen transfer coefficients (OTC), standard oxygen transfer rate (SOTR), and standard oxygenation efficiency (SOE) determined by clean water tests. Modules in series (module a, b, c) included one, two, and three venturi injectors, respectively. The aerator module with two (module d) and three (module e, f) venturi injectors in parallel were used, while module f had less friction and more even flow rate in each line compared with module e. The results showed that the OTC, SOTR, and SOE for the six different module configurations (module a, b, c, d, e, f) were 4.54, 3.79, 3.58, 8.37, 5.93 and 11.87 h−1; 0.10, 0.09, 0.09, 0.18, 0.15, and 0.31 kgO2/h; and 0.07, 0.06, 0.06, 0.12, 0.10, and 0.21 kgO2/kWh, respectively. The observations indicate that a 3-fold increase in SOTR and 3.5-fold increase in SOE can be obtained by simply changing the way that venturi air injectors are connected, which suggests that it is possible to improve the aeration efficiency of a venturi type aeration system by innovative aerator module designs. In view of the situation that the venturi aeration systems currently used for swine manure lagoons need significant improvement in their performance in order to match the cost-effective requirement, more research in aerator module development is needed so that effective control of odor from liquid swine manure lagoons can be achieved at an affordable cost. The technology such developed can also be applied to other livestock species.

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Brogdon, Jennifer, Charles L. McEntyre, Leanne Whitehead et Jerry Mitchell. « Enhancing the Energy Efficiency of Wastewater Aeration ». Proceedings of the Water Environment Federation 2008, n^o 17 (1 janvier 2008) : 444–51. http://dx.doi.org/10.2175/193864708788735547.

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Baylar, A., et M. E. Emiroglu. « Study of aeration efficiency at stepped channels ». Proceedings of the Institution of Civil Engineers - Water and Maritime Engineering 156, n^o 3 (septembre 2003) : 257–63. http://dx.doi.org/10.1680/wame.2003.156.3.257.

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Osuch, Ewa, et Stanisław Podsiadłowski. « Efficiency of pulverizing aeration on Lake Panieńskie ». Limnological Review 12, n^o 3 (1 mars 2012) : 139–45. http://dx.doi.org/10.2478/v10194-012-0054-4.

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AbstractThe principal threat to lakes of the temperate zone is posed by factors accelerating their eutrophication and causing marked deoxygenation of the deeper layers of water, mainly the hypo- and metalimnion. Among their effects are frequent phytoplankton blooms, including those of blue-green algae, and general deterioration of water quality also affecting the abundance and health status of fish. The chief concern is a disturbed proportion between the quantity of complex chemical compounds, especially organic, and the oxygen content of lake waters. Natural processes of water oxygenation are not too intensive, because they are practically limited to the epilimnion layer, connected as they are with the activity of aquatic plants of the littoral and sublittoral zone (which tends to disappear in contaminated lakes) and wind energy (the effect of waving). In summer conditions, with a relatively great chemical activity of bottom deposits, the intensity of those processes is usually inadequate. Hence, in 1995 research was launched in the Institute of Agricultural Engineering of the Agricultural University in Poznań on an integrated lake restoration technology whose core was a self-powered aerator capable of oxygenating also the bottom layers of water (the hypolimnion) of deep lakes. The aerator uses energy obtained from a Savonius rotor mainly to diffuse gases: to release hydrogen sulphide, which usually saturates the hypolimnion water completely, and then to saturate this water with oxygen. Even early studies showed the constructed device to be highly efficient in improving oxygen conditions in the bottom zone. They also made it clear that it should be equipped with an autonomous system designed to inactivate phosphorus, one of the principal factors determining the rate of lake degradation. In 2003 the first wind-driven pulverizing aerator equipped with such a system was installed in Lake Urban in Chodzież. The aim of this work is to present the principles of operation of a wind-driven pulverizing aerator with a phosphorus inactivation system, as well as its general technical characteristics and preliminary results of a study of its performance.

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Liu, Quan, Yimin Zhu, Tie Li, Xiaojia Tang, Weifeng Liu, Lin Guo et Jiao Zhao. « Modeling and prediction for the oxidation efficiency of magnesium sulfite in aeration tank of magnesium-based seawater exhaust gas clean system ». Proceedings of the Institution of Mechanical Engineers, Part M : Journal of Engineering for the Maritime Environment 233, n^o 1 (12 août 2017) : 164–73. http://dx.doi.org/10.1177/1475090217725619.

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In magnesium-based seawater exhaust gas clean system, the desulfurization by-product, magnesium sulfite (MgSO3), has a negative impact on the ecological environment, which needs to be treated to make harmless. Due to the limited space on board, the aeration oxidation method is used to convert it to magnesium sulfate. Because of the variable size, shape and flow field of aeration tank, it is difficult and expensive to design and verify the oxidation efficiency of the aeration tank by experimental method. In this work, in order to predict the oxidation efficiency accurately, RFlow, a computational fluid dynamics software, was used to analyze the flow field and MgSO3 oxidation reaction in aeration tank. The subdomain technology was adopted for physics modeling and mesh generation of the aeration tank, and the total number of meshes was 285,000. The multi-phase flow field model was set up using the multi-fluid model and dispersive k-ε turbulence model. Under the given initial conditions, the predicted oxidation efficiency was 94.2%. Compared with the results of the actual ship test, the prediction model for MgSO3 oxidation efficiency of the aeration tank is reliable.

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Chen, Jingna, Zefang Jiang, Yue Chen, Yu Qiu, Tingting Tao, Xiaoli Du et Jing Pan. « Pollutants removal, greenhouse gases emission and functional genes in wastewater ecological soil infiltration systems : influences of influent surface organic loading and aeration mode ». Water Science and Technology 83, n^o 7 (1 mars 2021) : 1619–32. http://dx.doi.org/10.2166/wst.2021.087.

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Abstract The influences of influent surface organic loading rate (SOLR) and aeration mode on matrix oxygen, organic matter, nitrogen, phosphorus removal, greenhouse gases emission and functional gene abundances in lab-scale wastewater ecological soil infiltration systems (WESISs) were investigated. In WESISs, intermittent or continuous aeration improved oxygen supply at 50 cm depth and hardly changed anaerobic condition below 80 cm depth, which enhanced chemical oxygen demand (COD), NH4+-N, total nitrogen (TN) removal, the abundances of bacterial 16S rRNA, amoA, nxrA, narG, napA, nirK, nirS, qnorB, nosZ genes and reduced CH4, N2O conversion efficiencies with SOLR of 16.9 and 27.6 g BOD/(m2 d) compared with non-aeration. Increased SOLR resulted in high TN removal, low N2O emission in aeration WESIS, which was different from non-aeration WESIS. High average COD removal efficiency of 90.7%, NH4+-N removal efficiency of 87.0%, TN removal efficiency of 84.6%, total phosphorus (TP) removal efficiency of 93.1% and low average N2O emission rate of 12.8 mg/(m2 d) were achieved with SOLR of 16.9 g BOD/(m2 d) in intermittent aeration WESIS. However, continuous aeration WESIS obtained high average removal efficiencies of 90.1% for COD, 87.5% for NH4+-N, 84.1% for TN, 92.9% for TP and low average emission rate of 13.1 mg/(m2 d) for N2O with SOLR of 27.6 g BOD/(m2 d). Aeration could be an optional strategy for WESISs to achieve high pollutants removal and low CH4, N2O emission when treating wastewater with high SOLR.

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Ujang, Z., M. R. Salim et S. L. Khor. « The effect of aeration and non-aeration time on simultaneous organic, nitrogen and phosphorus removal using an intermittent aeration membrane bioreactor ». Water Science and Technology 46, n^o 9 (1 novembre 2002) : 193–200. http://dx.doi.org/10.2166/wst.2002.0237.

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A laboratory-scale membrane bioreactor (MBR) was fed with synthetic wastewater to investigate the possibility of simultaneous removal of organic, nitrogen and phosphorus by intermittent aeration. The MBR consists of two compartments using a microfiltration membrane with 0.2 mm pore size and a surface area of 0.35 m2. Hydraulic retention time was set at 24 hours and solid retention time 25 days. MLSS concentration in the reactor was in the range of 2,500-3,800 mg/L. The MLSS internal recycling ratio was maintained at 100% influent flow rate. Intermittent aeration was applied in this study to provide an aerobic-anaerobic cycle. Three stages of operations were conducted to investigate the effect of aeration and non-aeration on simultaneous organic and nutrient removal. In Stage 1, time cycles of aeration and non-aeration were set at 90/150 min and 150/90 min in the first and second compartment, the removal efficiency was 97%, 94% and 70% for COD, nitrogen and phosphorus respectively. In Stage 2, time cycles of aeration and non-aeration were set at 60/120 min and 120/60 min in the first and second compartment, the removal efficiency was 97%, 96% and 71% for COD, nitrogen and phosphorus respectively. In Stage 3, time cycles of aeration and non-aeration were set at 120/120 min and 120/120 min in compartment 1 and 2, the removal efficiency was 98%, 96% and 78% for COD, nitrogen and phosphorus respectively. Results show that longer non-aeration time in the second compartment provided better performances of biological phosphorus removal.

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Li, Junchen, Yuheng Liu, Hongchuan Jiang, Mengxi Yang, Sijie Lin et Qing Hu. « A Multi-View Image Feature Fusion Network Applied in Analysis of Aeration Velocity for WWTP ». Water 14, n^o 3 (24 janvier 2022) : 345. http://dx.doi.org/10.3390/w14030345.

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The instability of the aeration system brings a significant challenge to the management of wastewater treatment plants (WWTP). Using image recognition methods to monitor aeration conditions accurately and enhance management efficiency is a promising way to solve this problem. To improve the efficiency of aeration condition identification and provide support for troubleshooting, we propose a method for aeration velocity condition identification based on a multi-view image feature fusion network (MVNN). Firstly, an experimental platform for simulating aeration tanks is established, and two cameras are used to acquire aeration images from different perspectives. Secondly, an image data set with 10 aeration velocity gradients is constructed and applied to the network’s training. Finally, the MVNN is used to extract and fuse the features of aeration images, and the model’s performance is evaluated on the dataset. Experiments show that the average accuracy of the method is over 98.3%, and the AUC of aeration identification is above 0.98, which indicates that the model has the potential for practical application in WWTP.

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Inomae, Katsuto, Hiroyuki Araki, Kenichi Koga, Youichi Awaya, Tetsuya Kusuda et Yasunari Matsuo. « Nitrogen Removal in an Oxidation Ditch with Intermittent Aeration ». Water Science and Technology 19, n^o 1-2 (1 janvier 1987) : 209–18. http://dx.doi.org/10.2166/wst.1987.0202.

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The typical process of nitrogen removal in the oxidation ditch is achieved through the control of oxygen supply ( forming aerobic and anoxic zones within the ditch channel) or alternating aeration using intermittently operating aerator(s). The operating conditions for efficient nitrogen removal with any of these methods have yet to be clarified. The purpose of this study is to establish an oxidation ditch system with a high rate of nitrogen removal by intermittent aeration. Effects of intermittent aeration on nitrogen removal characteristics were studied by experiments with a bench scale- and full scale-plant and by simulation. The conditions of optimum operation (aerobic and anoxic periods) for a high rate of nitrogen removal were found. These conditions principally depend upon the rates of nitrification and denitrification. By operating the full scale plant system with intermittent aeration ( cycle time is 45 minutes and aerobic ratio is 0.42 ), a high rate nitrogen removal efficiency of 81% was achieved without adding any alkaline matter or organic carbon sources. It was shown that the results of simulation agree with the observed data of the full scale plant system, and that the rate of denitrification depends upon the conditions of intermittent aeration.

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Liu, Xuyang, Xuejun Bi, Qing Huang, Xiaodong Wang, Ruihuan Gu et Xiaolin Zhou. « The Changing and Distribution Laws of Oxygen Transfer Efficiency in the Full-Scale IFAS Process ». Water 13, n^o 14 (13 juillet 2021) : 1933. http://dx.doi.org/10.3390/w13141933.

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The integrated fixed-film activated sludge (IFAS) process has been widely used in the upgrading of wastewater treatment plants (WWTPs). The oxygen transfer efficiency (αOTE) is of great significance to the design and operation of the IFAS process. The carrier filling ratio (CFR) and aeration type are two critical factors affecting αOTE and standard oxygen transfer efficiency (αSOTE). However, the distribution and changing laws of αOTE and αSOTE in the full-scale IFAS process areunclear. To optimize the operation of a WWTP and to improve the αOTE of the aeration systems, several off-gas tests were conducted under different aeration types and different CFRs. The results show that for the aerobic tank investigated (the ratio of length and width was 8:1), the αOTE and the αSOTE of the middle of the aeration systems were higher than those of the other two sides. However, the reason for the low αOTE at the beginning and the end of the tank may be different. Coarse-bubble aeration systems had a lower αOTE and almost the same oxygenation capacity (αSOTE) as the fine-bubble aeration systems under constant CFR (43%). The average αSOTE (18.7–28.9%) of the hybrid aeration systems increased with increasing CFR (7.7–57.7%), and different locations exhibited different degrees of change. The results reveal the distribution and changing law of the αOTE of aeration systems in the IFAS process, and attention should be paid to the improvement of the OTE of the plug-flow IFAS process.

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Stanojevic, Miroslav, Aleksandar Jovovic1, Dejan Radic et Milan Pavlovic. « Oxygen Transfer Efficiency of the Aeration Process in Refinery Waste Water Treatment ». Revista de Chimie 59, n^o 2 (9 mars 2008) : 220–25. http://dx.doi.org/10.37358/rc.08.2.1738.

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This paper presents the results of an experimental investigation of aeration of water with a corresponding mass concentration of waste motor oil depending on the height of the liquid column for varied flow of air introduced into the water. The aeration process for water column heights of 1 and 2 m were investigated. The purpose of investigations performed on an experimental installation was comparison of technical indicators of the aeration process depending on the height of the water column and air flow in order to achieve more efficient purification of waste water.

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Roy, Subha M., Mohammad Tanveer, C. K. Mukherjee et B. C. Mal. « Design characteristics of perforated tray aerator ». Water Supply 20, n^o 5 (20 avril 2020) : 1643–52. http://dx.doi.org/10.2166/ws.2020.069.

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Abstract The performance of the perforated tray aerator (PTA) was evaluated by conducting experiments in a tank of size 4 m × 4 m × 1.5 m. Based on the dimensional analysis, non-dimensional numbers related to geometric variables, viz. numbers of trays (n), ratio of consecutive width of tray to total height of aerator , ratio of perforation diameter to total height of aerator and ratio of the volume of water in the tank to total height of aerator were developed. Experiments were conducted with different numbers of trays (n): 1, 2, 3 and 4, keeping = 0.33, = 2.5 × 10−4, = 2,500 and pump flow rate (Q) = 0.010 m3/s as constants. The optimum number of perforated trays was found to be 3. Response surface methodology (RSM) and central composite rotatable design (CCRD) were used to further optimize the geometric variables with combinations of non-dimensional geometric variables , and . The flow rate (Q) of 0.013 m3/s and number of trays (n) as 3 were kept as constants. The optimum performance of PTA was obtained at = 0.665, = 1.85 × 10−4 and = 312.50 with the maximum non-dimensional standard aeration efficiency (NDSAE) and standard aeration efficiency (SAE) of 35.58 × 10−3 and 1.45 kgO2/kWh.

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Bahri, Samsul, Radite Praeko Agus Setiawan, Wawan Hermawan et Muhammad Zairin Junior. « The development of furrower model blade to paddlewheel aerator for improving aeration efficiency ». IOP Conference Series : Materials Science and Engineering 352 (mai 2018) : 012006. http://dx.doi.org/10.1088/1757-899x/352/1/012006.

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Su, Jung-Jeng, Yuan-Chie Chang et Shun-Ming Huang. « Ammonium reduction from piggery wastewater using immobilized ammonium-reducing bacteria with a full-scale sequencing batch reactor on farm ». Water Science and Technology 69, n^o 4 (14 décembre 2013) : 840–46. http://dx.doi.org/10.2166/wst.2013.787.

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This work aims to evaluate the efficiency of ammonium removal from piggery wastewater by an intermittent aeration (IA) sequencing batch reactor (SBR) with immobilized NH4+-reducing bacteria under mesophilic conditions. When a 20-L bench-scale SBR with 11% (v/v) of alginate beads containing NH4+-reducing bacteria was used, removal efficiency of NH4+ was 63% after 240 h. When a full-scale SBR system (available volume = 83 m3) with 0.1% (v/v) of alginate-coated light-expanded clay aggregates beads containing NH4+-reducing bacteria was used, removal efficiency of NH4+ by the full-scale intermittent aeration SBR (IA-SBR) was significantly different from both traditional intermittent aeration SBR (T-SBR) and the continuous aeration SBR with AL beads containing NH4+-reducing bacteria (P < 0.05). In summary, the IA-SBR with AL beads can significantly promote removal efficiency of NH4+ on farm.

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Yang, Yuli, Xiaojin Li, Xiaoli Yang et Zhen He. « Membrane aeration as an energy-efficient method for supplying oxygen to microbial fuel cells ». RSC Advances 6, n^o 55 (2016) : 49787–91. http://dx.doi.org/10.1039/c6ra09189j.

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Afifah, Anshah Silmi, I. Wayan Koko Suryawan et Ariyanti Sarwono. « Microalgae production using photo-bioreactor with intermittent aeration for municipal wastewater substrate and nutrient removal ». Communications in Science and Technology 5, n^o 2 (26 décembre 2020) : 107–11. http://dx.doi.org/10.21924/cst.5.2.2020.200.

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Microalgae has emerged as a promising approach for removing substrate and nutrient from wastewater with the concomitant biofuel production. The substrate and nutrient removal are influenced by several factors such as C/N ratio, F/M ratio, pH, and DO. This study aims to determine the efficiency of substrate and nutrient removal with the growth rates of microalgae and biomass by varying the addition of aeration and substrate. Intermittently aerated reactors were used with the flow rate of 14 L/minute. The batch reactors were prepared by adding glucose substrate of 50 mg/L (Ra0A), 100 mg/L (Ra0B), and 150 mg/L (Ra0C) without aeration; 50 mg/L (Ra12A), 100 mg/L (Ra12B), and 150 mg/L (Ra12C) with 12-hour aeration, and 50 mg/L (Ra24A), 100 mg/L (Ra24B), and 150 mg/L (Ra24C) with 24-hour aeration. The substrate removal, expressed as chemical oxygen demand (COD) in the reactor with aeration, showed the efficiency of 73.88% ± 2.05 (12-hour aeration), 75.2% ± 3.97 (24hours aeration), and 69.86% ± 5.69(without aeration). Nutrient removal as ammonia-N (NH3-N) gave high removal value of 98.3% ± 0.11 and the removal of nutrient as phosphate (PO3-4) showed the efficiency of 54.3% ± 0.1. The growth rate of microalgae and biomass exhibited the highest value in Ra24C reactor with the values ??of 0.0229/day and 0.1295/day, respectively. The pH values ??indicated a shift from normal to alkaline while DO values ??increased by the addition of 12 and 24-hour aeration.

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Chang, Gong Fa, Wei Hong, Xiao Bian, Bo Liu, Xin Tan et Ying Su. « The Effect of Aeration Rate on COD Removal from High Salinity Wastewater in SBR Process ». Applied Mechanics and Materials 522-524 (février 2014) : 605–8. http://dx.doi.org/10.4028/www.scientific.net/amm.522-524.605.

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Chemical companies, food industries usually produce wastewaters with high salinity. In consideration of economy, biological methods are preferred to physicochemical methods to remove organic matters. When sequence batching reactors are applied, aeration rate is of great importance to the COD removal efficiency. In this bench scale experiment, the aeration rate of 0.40 m3/m3.min led to sludge disintegration, poor COD removal efficiency and superfluous foam. After sludge conditioner addition, the aeration rate of 0.19 m3/m3.min led to good sludge flocs, satisfactory COD removal efficiency and few foam. It is the oxidizing environment caused by the high dissolved oxygen that harmed the sludge and made it work with low efficiency.

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J. Zhu, Z. Zhang et C. Miller. « Odor and Aeration Efficiency Affected by Solids in Swine Manure During Post-Aeration Storage ». Transactions of the ASABE 51, n^o 1 (2008) : 293–300. http://dx.doi.org/10.13031/2013.24223.

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Barber, Tyler W., Ken I. Ashley, Donald S. Mavinic et Ken Christison. « Superoxygenation : analysis of oxygen transfer design parameters using high-purity oxygen and a pressurized column ». Canadian Journal of Civil Engineering 42, n^o 10 (octobre 2015) : 737–46. http://dx.doi.org/10.1139/cjce-2015-0037.

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There remains significant potential for improvement in oxygen transfer efficiency, which can account for 60% of water and wastewater treatment energy requirements. This research examined superoxygenation, or aerating water under pressure with high-purity oxygen gas. Examined were the effects superoxygenation has on five key aeration design parameters: the mass transfer coefficient (KLa), saturation concentration ([Formula: see text]), standard oxygen transfer rate (SOTR), standard aeration efficiency (SAE), and standard oxygen transfer efficiency (SOTE). This research compared values under pressures of 0, 50, 100, 150, and 200 kPa using air and pressure swing adsorption (PSA) generated oxygen. It was found that with increasing pressure for both air and PSA oxygen: KLa decreased, [Formula: see text] increased, SOTR and SAE remained constant, and SOTE increased. While comparing air and PSA oxygen, oxygen was found to have a similar KLa, larger [Formula: see text], SOTR, and SOTE, and a lower SAE. It was concluded that superoxygenation is a viable method for increasing oxygen transfer and could potentially reduce oxygenation costs in water treatment processes.

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Duchène;, Ph, E. Cotteux et S. Capela. « Applying fine bubble aeration to small aeration tanks ». Water Science and Technology 44, n^o 2-3 (1 juillet 2001) : 203–10. http://dx.doi.org/10.2166/wst.2001.0771.

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Because the aeration system in an activated sludge plant typically represents a large part of the total energy requirements, designers and operators need accurate oxygen transfer information to make the aeration system as energy efficient as possible. This paper presents clean water tests performed at 38 wastewater treatment plants. The Specific Aeration Efficiency results (SAE, kgO2/kWh) are reported for: (1) large open channels (volume higher than 1000 m3), (2) small open channels, (3) total floor coverage cylindrical tanks, and (4) cylindrical tanks with a grid arrangement. Some practical guidelines can be drawn, some of them being: (1) high SAE can be achieved at small aeration tanks (<1000m3), applying cylindrical tanks with a total floor coverage arrangement of diffusers, volumetric blowers, and moderate air flow rates per diffuser area; (2) the high investment cost of this configuration can be justified with respect to a grid layout characterized by spiral liquid circulation which affects the oxygen transfer; (3) small open channels can meet sufficient SAE values but fail to meet in this range of tank volumes those of total floor coverage cylindrical tanks.

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Nam, KiJeon, SungKu Heo, Jorge Loy-Benitez, Pouya Ifaei et ChangKyoo Yoo. « An autonomous operational trajectory searching system for an economic and environmental membrane bioreactor plant using deep reinforcement learning ». Water Science and Technology 81, n^o 8 (10 février 2020) : 1578–87. http://dx.doi.org/10.2166/wst.2020.053.

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Abstract Optimal operation of membrane bioreactor (MBR) plants is crucial to save operational costs while satisfying legal effluent discharge requirements. The aeration process of MBR plants tends to use excessive energy for supplying air to micro-organisms. In the present study, a novel optimal aeration system is proposed for dynamic and robust optimization. Accordingly, a deep reinforcement learning (DRL)-based optimal operating system is proposed, so as to meet stringent discharge qualities while maximizing the system's energy efficiency. Additionally, it is compared with the manual system and conventional reinforcement learning (RL)-based systems. A deep Q-network (DQN) algorithm automatically learns how to operate the plant efficiently by finding an optimal trajectory to reduce the aeration energy without degrading the treated water quality. A full-scale MBR plant with the DQN-based autonomous aeration system can decrease the MBR's aeration energy consumption by 34% compared to other aeration systems while maintaining the treatment efficiency within effluent discharge limits.

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Suriasni, Putu Ayustin, Ferry Faizal, Camellia Panatarani, Wawan Hermawan et I. Made Joni. « A Review of Bubble Aeration in Biofilter to Reduce Total Ammonia Nitrogen of Recirculating Aquaculture System ». Water 15, n^o 4 (19 février 2023) : 808. http://dx.doi.org/10.3390/w15040808.

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Aeration becomes an essential aspect of biofilter performance to reduce ammonia nitrogen in the Recirculating Aquaculture System (RAS). Efficient aeration introduces air into water media and offers an aerobic environment in the biofilter for microbial degradation of organic matter and ammonia nitrogen. The efficiency of the bubble aeration depends on the size of the bubbles; these include coarse bubble, microbubble, fine bubble, and ultrafine bubble or nanobubble. This review highlights an overview of bubble aeration features in a biofilter to reduce ammonia nitrogen. Moreover, key aspects responsible for the ammonia nitrogen removal efficiencies, such as oxygen transfer, microbial community, and biofilm thickness, are evaluated in this review. In conclusion, the bubble size of aeration affects the microbial community of nitrifying bacteria, consequently determining the growth and thickness of biofilm to improve ammonia removal efficiency. It is emphasized that fine bubble and nanobubble aeration have very positive prospects on improving biofilter performance, though they are currently not widely used in RAS.

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Moulick, Sanjib, Naresh V. Tambada, Basant K. Singh et B. C. Mal. « Aeration characteristics of a rectangular stepped cascade system ». Water Science and Technology 61, n^o 2 (1 janvier 2010) : 415–20. http://dx.doi.org/10.2166/wst.2010.828.

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Aeration experiments, maintaining nappe flow conditions, were carried out on a rectangular stepped cascade of total height 3.0 m to determine the total number of steps, slope of the entire cascade and hydraulic loading rate at which maximum overall aeration efficiency occurs, keeping the surface area of individual steps constant. Based on dimensional analysis, the overall aeration efficiency at standard conditions (E20) was expressed as a function of square of total number of steps (N2) and dimensionless discharge (dc/h), where dc and h represent critical depth in a rectangular prismatic channel and individual step height respectively. An empirical equation with E20 as the response and N2 and dc/h as the independent parameters was developed based on the experimental results subject to 36 ≤ N2 ≤ 196 and 0.009 ≤ dc/h ≤ 0.144. The experimental results showed that the overall aeration efficiency (E20) for a particular step height of stepped cascade increases with increase in dc/h up to a certain value and then decreases. This may be due to at higher dc/h, i.e., at higher hydraulic loading rate, the flow approaches the transition zone and thereby aeration efficiency decreases. E20 was also found to increase with number of steps at any hydraulic loading rate, because of the increased surface area of fall. The optimum number of steps, slope of the entire stepped cascade and hydraulic loading rate were found to be 14, 0.351 and 0.009 m2/s respectively producing the maximum value of overall aeration efficiency of 0.90.

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Qiu, Yong, Chi Zhang, Bing Li, Ji Li, Xiaoyuan Zhang, Yanchen Liu, Peng Liang et Xia Huang. « Optimal Surface Aeration Control in Full-Scale Oxidation Ditches through Energy Consumption Analysis ». Water 10, n^o 7 (16 juillet 2018) : 945. http://dx.doi.org/10.3390/w10070945.

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Oxidation ditches are popularly used in rural areas and decentralized treatment facilities where energy deficiency is of concern. Aeration control technologies are well established for diffusion systems in order to improve energy efficiency, but there are still challenges in their application in oxidation ditches because surface aerators have unique characteristics with respect to oxygen transfer and energy consumption. In this paper, an integral energy model was proposed to include the energy, aeration, and fluidic effects of surface aerators, by which the energy for aeration of each aerator can be estimated using online data. Two types of rotating disks with different diameters (1800 mm and 1400 mm) were monitored in situ to estimate the model parameters. Furthermore, a feedforward–feedback loop control strategy was proposed using the concept of energy analysis and optimization. The simplified control system was implemented in a full-scale Orbal oxidation ditch, achieving an approximately 10% saving in full-process energy consumption. The cost–benefit analysis and carbon emission assessment confirmed the economic feasibility and environmental contribution of the control system. The energy model can help process designers and operators to better understand and optimally control the aeration process in oxidation ditches.

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Baylar, A., et M. E. Emiroglu. « Erratum : Study of aeration efficiency at stepped channels ». Proceedings of the Institution of Civil Engineers - Water Management 157, n^o 4 (décembre 2004) : 222. http://dx.doi.org/10.1680/wama.2004.157.4.222.

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