Yazar "Cengiz, Ibrahim" seçeneğine göre listele

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    Comparison of phenol removal with ozonation in jet loop reactor and bubble column
    (Elsevier Sci Ltd, 2020) Barlak, Melahat Semin; Degermenci, Nejdet; Cengiz, Ibrahim; Ozel, Handan Ucun; Yildiz, Ergun
    This study aimed to remove phenol with ozonation in a jet loop reactor (JLR) and a bubble column (BC). In the first stage of the study, the mass transfer properties of JLR were determined and superiority over BC reactors were shown, and in the second stage, these reactors were used in phenol removal studies. At the same conditions, the volumetric mass transfer coefficient of JLR was 0.540 min-1, while this value was determined as 0.246 min(-1) in the BC reactor. In phenol removal, the effects of initial phenol concentration, ozone dosage and pH on phenol and chemical oxygen demand (COD) removal were determined for both JLR and BC. While the pseudo-first rate constant for phenol removal in JLR at 221 mg/min ozone dosage was 0.1756 min(-1), this value was only calculated as 0.1157 min(-1) in the BC reactor. As a result, it has been shown that JLRs can achieve higher ozone gas transfer with lower energy consumption and perform more effective phenol and COD removal than BC reactors, especially at low pH and high ozone dosages.
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    High-speed treatment of low strength domestic wastewater for irrigation water production in pilot-scale classical, moving bed and fixed bed hybrid MBRs
    (Elsevier Sci Ltd, 2022) Tuluk, Banu; Yildiz, Ergun; Nuhoglu, Alper; Tataroglu, Numan Suadi; Gulluce, Ekrem; Cengiz, Ibrahim; Degermenci, Nejdet
    To evaluate the treatability of domestic wastewater under conditions of low hydraulic retention time and high organic loadings, 3 pilot-scale automatically controlled membrane bioreactors (MBRs) as classical (C-MBR), moving bed (MB-MBR), and fixed bed (FB-MBR) were established and operated for a total of 268 days. Estab-lished pilot plants were compared in terms of treatment performance, membrane fouling, irrigation water criteria, and power consumption values. Results obtained have shown that all three systems were able to achieve more than 93% removal of chemical oxygen demand (COD) in an average hydraulic retention time (HRT) of 1 hour, and MB-MBR and FB-MBR were superior in terms of total nitrogen (TN) and total phosphorus (TP) re-movals. It has been determined that MB-MBR and FB-MBR are also advantageous in terms of power consumption. Especially it has been found that FB-MBR can produce better quality irrigation water with 40% lower power consumption than C-MBR under the same conditions. It was concluded that biofilm-supported hybrid systems could be a practical application in the fight against increasing water scarcity and global warming, both in obtaining clean water with less power consumption and in protecting human and environmental health.
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    Investigation of ammonia stripping with a hydrodynamic cavitation reactor
    (Elsevier, 2020) Tasdemir, Atila; Cengiz, Ibrahim; Yildiz, Ergun; Bayhan, Yalcin Kemal
    Ammonia is a commonly used compound in the domestic and industrial fields. If ammonia found in wastewater after use is not treated, even at low concentrations it may cause toxic effects in the receiving environment. In this study, a hydrodynamic cavitation reactor (HDC) was designed with the aim of removing ammonia. The effect of parameters like different cavitation numbers, airflow, temperature and initial concentration on NH3 removal was researched. The potential of hydrodynamic cavitation for removal of volatile gases, like NH3, was assessed with the aid of two film theory mathematical equations. Experimental studies were performed at fixed pH = 11. Under the conditions of 0.12 cavitation number, 25 L/min airflow, 30 degrees C temperature and 2500 mg/L initial concentration, in 24 h 98.4% NH3 removal efficiency was achieved. With the same experimental conditions without any air, the HDC reactor provided 89.5% NH3 removal at the end of 24 h. The HDC reactor is very effective for the removal of volatile gases from wastewater and it was concluded that even in the absence of aeration, the desired NH3 removal efficiency was provided.
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    THE INVESTIGATION OF FLOW RATE EFFECT ON LEACHATE TREATMENT BY ELECTROOXIDATION PROCESS
    (Yildiz Technical Univ, 2020) Yilmaz, Alper Erdem; Dede Sagsoz, Yesim; Sakarya, Merve; Cengiz, Ibrahim
    In the study, the leachate of the Erzurum Municipality Solid Waste Regular Storage Facility was used. Leaching waters formed in solid waste storage areas and the contents depend on rainfall and the characteristics of the stored waste. The leachate includes a high amount of organic matter it contains, nitrogenous substances, heavy metals, high salinity; it causes pollution of underground and surface receiving environments. Therefore leachate must be treated before being discharged. For this purpose, an electrooxidation process was used for the treatment of leachate. The effect of the flow rate change on the treatment efficiency in the continuous electrooxidation process is investigated. The flow rate was selected as 5, 7.5, and 10 ml/min. The constant current of 20 A was applied with a direct current intensity supply (40 V-250 A) in 600 ml. In the reactor (600 ml) at a constant current of 20 A, the effluent water temperature increased from 15 degrees C to 31 degrees C while the pH value was reduced to a value of 8.2 to 4.8. At the constant current of 20 A, approximately 90% chemical oxygen demand (COD) removal was obtained at a flow rate of 5 ml/min, which is the best removal efficiency obtained from flow rate experiments. It is seen from the same study results that the energy consumption value is 55 kWh/m(3) at 20 A current and 5 ml/min flow rate. As a result, the electrooxidation process can be used for the treatment of leachate, especially for organic matter removal.
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    Investigation of Mass Transfer of Ozone in Jet Loop Reactor
    (Korean Institute Chemical Engineers, 2024) Cengiz, Ibrahim; Degermenci, Nejdet; Yildiz, Ergun; Barlak, Melahat Semin
    Mass transfer of ozone in a jet loop reactor was investigated in this study. Different parameters such as ozone gas concentration, gas flow rate, circulation flow rate, and spray nozzle diameter were examined for their effect on mass transfer. In experiments with ozone gas concentrations ranging from 3.83 to 17.1 g/m3, the KLa values remained unchanged, with an average of 28.7 +/- 2.2 h-1. As the ozone gas concentration increased, the saturation values of ozone in the liquid phase also increased. Experiments were carried out with gas flow rates ranging from 50 to 250 L/h in the jet loop reactor, and increasing gas flow rates increased the KLa value up to five times. When the effect of the liquid circulation flow rate was examined for a spray nozzle diameter of 15.5 mm, increasing the flow rate from 40 L/min to 80 L/min increased the KLa value by approximately 41%. However, the power consumed per reactor volume for this process increased 8 times and reached 2.65 kW/m3. KLa values in the JLR vary between 6.1 and 37.3 h-1 depending on operating parameters and it has been concluded that it performs well compared to its counterparts.