Person: ÜSTÜN, GÖKHAN EKREM
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ÜSTÜN
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GÖKHAN EKREM
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Publication Kinetic investigations of gibberellic acid oxidation in aqueous solutions by fenton and photo-fenton processes(Parlar Scientific Publications (P S P), 2015-01-01) Üstün, Gökhan Ekrem; ÜSTÜN, GÖKHAN EKREM; Bursa Uludağ Üniversitesi/Mühendislik Fakültesi/Çevre Mühendisliği Bölümü; 0000-0002-7126-6792; AAG-8439-2021The degradation of gibberellic acid (GA(3)) from aqueous solution has been carried out by the different oxidation processes: UV, UV/H2O2, Fenton and photo-Fenton processes. The effect of operating parameters such as Fe2+, H2O2 concentrations, UV-A light intensity and initial pH was studied. It is possible to create a strongly irradiated region along the axis of cylindrical photochemical reactor throughout the photo-Fenton process. The increased intensity of UV-A light due to the degradation and mineralization of GA(3) during the photo-Fenton process was explored. The highest GA(3) removal efficiency was achieved at 0.08 mM/1 mM Fe2+/H2O2 at pH 3 for Fenton processes. The removal efficiencies of GA(3) and TOC were 60 % and 5 %, respectively. GA(3) degradation was completed and 16% TOC removal was achieved by the photo-Fenton process at 45 x 10(-6) Einstein s(-1) UV-A light intensity. The kinetics of degradation and mineralization were found to follow first-order reaction rules in both processes.Publication Experimental design of fenton process for the oxidation and mineralization of monocrotophos(Wiley, 2015-09-01) Üstün, Gökhan Ekrem; Solmaz, Şeval Kutlu Akal; Azak, Hilal Safiye; ÜSTÜN, GÖKHAN EKREM; AKAL SOLMAZ, SEVAL KUTLU; Uludağ Üniversitesi/Mühendislik Fakültesi/Çevre Mühendisliği Bölümü.; 0000-0002-7126-6792; AAH-1967-2021; AAG-8439-2021In this study, the Fenton treatment of Monocrotophos (MCP) was evaluated in terms of oxidation and mineralization efficiency using response surface methodology (RSM). The effects of MCP, Fe2+, H2O2 concentrations and reaction time, and the interactions between these factors on (i) the oxidation efficiency of MCP and (ii) the mineralization of MCP were studied. Hence, the objective of this study was to optimize MCP oxidation and mineralization by the Fenton process (FP) using RSM. The obtained optimum conditions for MCP oxidation and mineralization using FP were 0.022: 0.03: 0.15 MCP/Fe2+/H2O2 and a reaction time of 65 min. MCP was mineralized easily through the Fenton reaction. The MCP oxidation efficiency was 90% and the mineralization efficiency was 66%. The initial MCP concentration was the most significant variable affecting both the oxidation and mineralization efficiency of MCP. Addition of Fe2+ had a more significant effect on the MCP oxidation compared to the MCP mineralization.Publication The effect of irrigation of pickling cucumber with urban wastewater on product quality and heavy metal accumulation(Springer, 2022-08-22) Akbudak, Nuray; Üstün, Gökhan Ekrem; AKBUDAK, NURAY; ÜSTÜN, GÖKHAN EKREM; Bursa Uludağ Üniversitesi/Ziraat Fakültesi/Bahçe Bitkileri Bölümü; Bursa Uludağ Üniversitesi/Mühendislik Fakültesi/Çevre Mühendisliği Bölümü; 0000-0002-7126-6792; AAG-8439-2021; EKS-0323-2022Pickled cucumber is one of the vegetables that needs water frequently during its cultivation and is processed and evaluated, and it is consumed high all over the world. In arid and semi-arid regions, wastewater is commonly used for vegetables and forage crop irrigation. In this study, a comparative field study was carried out using untreated wastewater (U), treated wastewater (T), and tap water for control (C) irrigation for the growing of cucumber pickled plants. Plant phenological and some growth parameters, fruit quality parameters, fruit, and leaf color, photosynthetic pigments, phenolic compound, vitamin C and heavy metal (HM) contents (Cr, Ni, Cd, Pb, Cu) in different parts of the plant were defined. In addition, crop productivity was measured by the means of fruit weight and diameter, and length. The results show that plant length and yield of pickling cucumbers increased by 40.90% in U, and 4.39% in T. The plants in U applications were started to harvest 5 days ago when compared with the others. On a positive note, U led to an increase in vitamin C levels and phenolic compounds. Collectively, the data suggest that U can help add value to pickling cucumber by increasing its antioxidant activity as compared to other irrigation water sources. The accumulation in the leaves was Ni > Cr > Cu > Pb > Cd, respectively. Based on the results, this study concludes that it is possible to use wastewater for cucumber irrigation. Since the edible parts of pickling cucumber are consumed after processing, they do not pose a risk to public health. This study may provide a basis for application of using untreated wastewater in high quality cucumber production.Publication Characteristics and seasonal variation of microplastics in the wastewater treatment plant: The case of Bursa deep sea discharge(Pergamon-elsevier Science Ltd, 2023-07-14) Üstün, Gökhan Ekrem; ÜSTÜN, GÖKHAN EKREM; Kaya, Yunus; Can, Tuğba; Bursa Uludağ Üniversitesi/Mühendislik Fakültesi/Çevre Mühendisliği Bölümü.; 0000-0002-7126-6792; GRS-0367-2022Microplastics (MPs) are an emerging pollutant that can be detected in all ecosystems, especially aquatic ecosystems. Wastewater treatment plants (WWTPs) are important point sources of MP release into the sea. In this study, the characteristics of MPs in wastewater and sludge samples taken from different units of WWTP in BursaGemlik district for 12 months were investigated. Wastewater and sludge samples collected from 7 different points were classified as size, shape, color, and counted. The amount of MP in the influent and effluent of the WWTP, respectively; 107.1 & PLUSMN; 40.2 MP/L and 4.1 & PLUSMN; 1.1 MP/L. Although the MP removal efficiency of the WWTP is 96.17 %, approximately 74,825,000 MP is discharged into the Marmara Sea every day. The amount of MP in the sludge is 14.3 & PLUSMN; 7.1 MP/g. The amount of MP accumulated in 22tons of waste sludge formed daily in WWTP was calculated as 314,600,000 MP, and the annual accumulated amount was calculated as approximately 1.15 x 1011 MP. The MPs in the WWTP were mainly 1-0.5 mm in size. Fibers were the dominant MP shape in both the wastewater and sludge samples. Black and transparent were the dominant MP colors. Seven different polymer types of MPs were detected, which were mainly types of polyethylene, polypropylene, and polyethylene terephthalate. Despite the high removal efficiency in the investigated WWTP, it has been shown that it acts as an important source of MPs to the sea ecosystem due to the high discharge rates.