Environmental Engineering / Çevre Mühendisliği

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Access type: Open accessInstitution Author: search.filters.institutionAuthor.Ökten, Hatice Eser

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  • Article
    Citation - WoS: 10
    Citation - Scopus: 12
    Novel Hybrid Adsorption-Electrodialysis (aded) System for Removal of Boron From Geothermal Brine
    (American Chemical Society, 2022) Altınbaş, Bekir Fırat; Orak, Ceren; Ökten, Hatice Eser; Yüksel, Aslı
    A novel hybrid adsorption-electrodialysis (AdED) system to remove environmentally harmful boron from geothermal brine was designed and effective operating parameters such as pH, voltage, and flow rate were studied. A cellulose-based adsorbent was synthesized from glycidyl methacrylate (GMA) grafted cellulose and modified with a boron selective n-methyl-d-glucamine (NMDG) group and characterized with SEM-EDX, FT-IR, and TGA analyses. Batch adsorption studies revealed that cellulose-based adsorbent showed a remarkable boron removal capacity (19.29 mg/g), a wide stable operating pH range (2-10), and an adsorption process that followed the Freundlich isotherm (R2= 0.95) and pseudo-second-order kinetics (R2= 0.99). In the hybrid AdED system, the optimum operating parameters for boron removal were found to be a pH of 10, a voltage of 10 V, a flow rate of 100 mL/min, and an adsorbent dosage of 4 g/L. The presence of the adsorbent in the hybrid system increased boron removal from real geothermal brine (containing 199 ppm boron) from 7.2% to 73.3%. The results indicate that the designed AdED system performs better than bare electrodialysis for boron removal from ion-rich real geothermal brine while utilizing environmentally friendly cellulose-based adsorbent.
  • Article
    Citation - WoS: 40
    Citation - Scopus: 47
    Boron in Geothermal Energy: Sources, Environmental Impacts, and Management in Geothermal Fluid
    (Elsevier, 2022) Mott, A.; Baba, Alper; Hadi Mosleh, Mojgan; Ökten, Hatice Eser; Babaei, Masoud; Gören, Ayşegül Yağmur; Feng, C.; Recepoğlu, Yaşar Kemal; Uzelli, Taygun; Uytun, Hüseyin; Morata, Diego; Yüksel Özşen, Aslı
    The problem of hazardous chemicals in geothermal fluid is a critical environmental concern in geothermal energy developments. Boron is among the hazardous contaminants reported to be present at high concentrations in geothermal fluids in various countries. Poor management and inadequate treatment of geothermal fluids can release excessive boron to the environment that has toxic effects on plants, humans, and animals. Despite the importance of boron management in geothermal fluid, limited and fragmented resources exist that provide a comprehensive understanding of its sources, transport and fate, and the treatment strategies in geothermal energy context. This paper presents the first critical review from a systematic and comprehensive review on different aspects of boron in geothermal fluid including its generation, sources, toxicity, ranges and the management approaches and treatment technologies. Our research highlights the origin of boron in geothermal water to be mainly from historical water-rock interactions and magmatic intrusion. Excessive concentrations of boron in geothermal fluids have been reported (over 500 mg/L in some case studies). Our review indicated that possible boron contamination in geothermal sites are mostly due to flawed construction of production/re-injection wells and uncontrolled discharge of geothermal water to surface water. The dominancy of non-ionic H3BO3 species makes the selection of the suitable treatment method for geothermal waters limited. Combining boron selective resins and membrane technologies, hybrid systems have provided effluents suitable for irrigation. However, their high energy consumption and course structure of boron selective resins encourage further research to develop cost-effective and environmentally friendly alternatives.
  • Article
    Citation - WoS: 13
    Citation - Scopus: 14
    Desalination and Detoxification of Textile Wastewater by Novel Photocatalytic Electrolysis Membrane Reactor for Ecosafe Hydroponic Farming
    (MDPI, 2022) Aydın, Muhammed Iberia; Özaktaç, Damla; Yüzer, Burak; Doğu, Mustafa; İnan, Hatice; Ökten, Hatice Eser; Coşkun, Serdar; Selçuk, Hüseyin
    In this study, a novel photoelectrocatalytic membrane (PECM) reactor was tested as an option for the desalination, disinfection, and detoxification of biologically treated textile wastewater (BTTWW), with the aim to reuse it in hydroponic farming. The anionic ion exchange (IEX) process was used before PECM treatment to remove toxic residual dyes. The toxicity evaluation for every effluent was carried out using the Vibrio fischeri, Microtox® test protocol. The disinfection effect of the PECM reactor was studied against E. coli. After PECM treatment, the 78.7% toxicity level of the BTTWW was reduced to 14.6%. However, photocatalytic desalination during treatment was found to be slow (2.5 mg L-1 min-1 at 1 V potential). The reactor demonstrated approximately 52% COD and 63% TOC removal efficiency. The effects of wastewater reuse on hydroponic production were comparatively investigated by following the growth of the lettuce plant. A detrimental effect was observed on the lettuce plant by the reuse of BTTWW, while no negative impact was reported using the PECM treated textile wastewater. In addition, all macro/micronutrient elements in the PECM treated textile wastewater were recovered by hydroponic farming, and the PECM treatment may be an eco-safe wastewater reuse method for crop irrigation.
  • Article
    Citation - WoS: 7
    Citation - Scopus: 9
    3d Electrode Use in Mdc for Enhanced Removal of Boron From Geothermal Water
    (Elsevier, 2022) Gören, Ayşegül Yağmur; Ökten, Hatice Eser
    Microbial desalination cell (MDC) is a significantly promising technology due to its simultaneous features of electricity production, wastewater treatment and desalination. In this paper, the three-dimensional (3D) sponge with activated carbon-chitosan (AC-CS) was synthesized to enhance the efficiency of the MDC system. Effects of operating parameters (boron concentration, electrode surface area, catholyte solution, and activated sludge volume) on MDC performance were also investigated. The MDC with 3D AC-CS anode provided a higher power density of 970 mW/m2, boron removal efficiency of 75.9%, and COD removal efficiency of >90% under optimized conditions. The maximum boron and COD removal efficiencies were 65.6 and 81.4% with the power density of 866.9 mW/m2 for geothermal brine. Moreover, BET analysis showed that the 3D AC-CS anode presented high surface area (230 m2/g) and pore volume (0.202 cm3/g). As an overall result, not only the production of 3D sponge anode electrodes with AC-CS composite was achieved but also desalination and power generation results that were comparable with the literature were presented.
  • Article
    Noktasal Kaynaklar için Ulusal Hava Kirliliği Emisyon Faktörleri ve Envanterinin Belirlenmesi: Metal Sektörü için Örnek Bir Çalışma
    (Marmara Üniversitesi, 2021) Özdemir, Hüseyin; Aktaş, Muhammet Ali; Yalçın, İbrahim Ertuğrul; Alyüz, Ümmügülsüm; Ökten, Hatice Eser; Özcan, H. Kurtuluş; Köksal, Canan Esin; Çetintürk Gürtepe, İrde; Demir, Göksel; Ünal, Alper
    Hava kalitesinin korunması için yürütülen çalışmalar ve yasal uygulamalar, günümüzde çevre bilincinin artması ile daha daönemli hale gelmiştir. Yenilenebilir enerji kullanımının yaygınlaştırılması gibi çevre dostu düzenlemeler ile hava kalitesininiyileştirilmesi artık ülke politikalarında yer almaktadır. Hava kalitesinin yükseltilmesine yönelik yasal düzenlemelerinhazırlanmasında mevcut durumun ortaya konması büyük önem taşımaktadır. Atmosfere verilen kirliliğin miktarının doğruolarak tespit edilebilmesi ve illerin temiz hava eylem planlarının hazırlanabilmesi için ulusal ölçekte, kaynaklarına göre havakirleticilerinin emisyon envanterinin hesaplanması, ulusal ve uluslararası sorumluluklar gereği atmosfere verdiğimizemisyonların belirli periyotlarda raporlanması gerekmektedir. Bu nedenle, emisyon envanterinin belirli bir düzen içerisinde,kirlilik kaynaklarına ait veriler ve yerel emisyon faktörleri kullanılarak hazırlanması gerekmektedir. Bu çalışmada, MarmaraBölgesi pilot bölge seçilerek Çevre ve Şehircilik Bakanlığı ile birlikte ülkemizde ilk defa ulusal emisyon envanteri geliştirilmesiprojesi gerçekleştirilmiştir. Bu çalışmadaki noktasal kaynaklar için yapılan kısım bu makalede anlatılmış ve metal sektörüyleilgili elde edilen sonuçlar verilmiştir. Marmara Bölgesi’ndeki metal sektörünün emisyon envanteri hesaplamasında 27 tesisin128 emisyon kaynak bilgisi kullanılmıştır. Ulusal emisyon faktörleriyle yapılan hesaplamalara göre emisyon değerleri; CO için46.849 ton/yıl, SO2 için 7.589 ton/yıl, NOx için 8.906 ton/yıl ve TSP için 1.759 ton/yıl bulunmuştur.
  • Article
    Phytoremediation of Boron Containing Synthetic Aqueous Solutions and Real Geothermal Water Using Lemna Minor
    (2021) Ökten, Hatice Eser; Gören, Ayşegül Yağmur
    In this paper, phytoremediation performance of Lemna minor L. on boron (B) removal from synthetic solution and real geothermal brine was evaluated. Effects of B concentration, initial pH, water height in cell, and initial humic acid concentration were investigated. The maximum removal efficiency was 96.7 % with the experimental run with B concentration of 5 mg L-1, pH 8, and 1.5 cm water depth. Increasing the B concentration from 5 to 30 mg L-1 resulted in a drastic decrease in removal efficiency to 36.6 %, due to the toxic effect of high boron content, which was clearly observed from deterioration of plant’s color and structure. SEM, FTIR, and mass balance analyses revealed that the boron removal mechanism was mainly biosorption. Geothermal water experiments indicated L. minor’s applicability with 59.5% removal efficiency, proving high potential in being used for post-treatment of geothermal waters with high boron content.
  • Article
    Citation - WoS: 15
    Citation - Scopus: 18
    Simultaneous Energy Production, Boron and Cod Removal Using a Novel Microbial Desalination Cell
    (Elsevier, 2021) Gören, Ayşegül Yağmur; Ökten, Hatice Eser
    This paper investigates simultaneous boron removal from aqueous solutions, organic matter removal from industrial wastewater and energy production using a Microbial Desalination Cell (MDC). Anode chamber of the conventional MDC cell was modified to include 3D cubic electrodes as a novel design. Effects of operating parameters, including electrode type (3D-electrode and 2D-electrode), anolyte solution temperature (20 °C, 40 °C, and 60 °C), and activated sludge:wastewater volumetric ratio (S:WW = 1:1, 1:2, and 1:5), on MDC performance were studied. Furthermore, real geothermal water treatment was investigated under optimum operating conditions. Boron and organic matter removal efficiencies and the produced power density results were promising for 3D-electrodes under optimum operating conditions. The maximum boron removal efficiency, COD removal efficiency, and power density were 55.5%, 91.5%, and 9.04 mW/m3 treating real geothermal water at optimum operating conditions. The analyses of Scanning Electron Microscope with Energy Dispersive X-ray spectrometer (SEM-EDX) demonstrated biofilm formation and salt deposition on membrane surfaces, which most probably reduced the performance of MDC. Consequently, our results showed that use of 3D-electrodes was a promising improvement to the conventional configurations with 2-D electrodes since removal efficiencies and energy production were comparable for a more compact electrode structure.
  • Article
    Fotobiyokataliz Yöntemi Kullanılarak Pestisit Giderimi-derleme Çalışması
    (Niğde Ömer Halisdemir Üniversitesi, 2019) Okçu, Gamze; Ökten, Hatice Eser; Yalçuk, Arda
    Aromatik yapılı, çevresel koşullarda zorlukla parçalanabilen, kararlı organik kirleticilerin başında gelen pestisitler, atmosfere, su sistemlerine, besin zincirine taşınmakta, asıl kaynaklarından çok uzak noktalarda birikebilmektedir. Konvansiyonel arıtma proseslerinin pestisitlerin gideriminde yetersiz kalmasından dolayı kirletilmiş sulardan uzaklaştırılmaları için yeni arıtım teknolojilerine ihtiyaç duyulmaktadır. Son yıllarda, su sistemlerinden konvansiyonel tekniklerle arıtılamayan kirleticilerin giderilmesinde birleşik fotokatalitik-biyolojik arıtma umut verici bir alternatiftir: Fotokataliz toksik organikleri biyolojik olarak parçalanabilir ürünlere dönüştürürken, biyolojik parçalama ürünlerini verimli şekilde mineralize eder. Ön arıtma sırasında gereksiz kimyasal ve %60 oranında enerji sarfiyatından kaçınmak amacıyla ön arıtma basamağında mineralizasyon yüzdesi minimalize edilerek çalışma maliyeti düşürülür. Literatüre göre yalnız kimyasal prosesle yaklaşık %80 pestisit parçalanması ve %50’den az mineralizasyon gözlemlenebilirken hibrit reaktör sistemiyle tamamen parçalanma ve yaklaşık %90 pestisit mineralizasyonu elde edilebilmektedir. Bu derlemenin amacı, fotobiyokataliz işleminin, bireysel fotokataliz ve/veya biyolojik arıtma yöntemlerine göre pestisit giderim koşulları kapsamında, temellerini, mekanizmalarını ve literatürde yer alan güncel çalışmaları ele almak ve incelemektir.
  • Article
    Citation - Scopus: 5
    Effect of Covid-19 Pandemic on Ambient Air Quality and Excess Risk of Particulate Matter in Turkey
    (2021) Gören, Ayşegül Yağmur; Genişoğlu, Mesut; Ökten, Hatice Eser; Sofuoğlu, Sait Cemil
    The COVID-19 pandemic, which has reached 4 million global cases as of March 10, 2020, has become a worldwide problem. Turkey is one of the most affected (9th in the world) country with 139 771 cases. An intermittent curfew policy that differ for three age groups, and an intercity travel ban varying within the country have been implemented. The effects of changes in social life and industrial activity in terms of environmental pollution are not yet known. The short-term effects on PM2.5, PM10, SO2, NO2, NO, NOx, O3 and CO concentrations measured at 51 air quality measurement stations (AQMS) in 11 cities in March – April period of 2020 were statistically compared with that of the previous year. While PM2.5 (9/14 AQMS) and PM10 (29/35 AQMS) concentrations were not significantly affected, NO (12/24 AQMS), NO2 (20/29 AQMS), NOX (17/25 AQMS) concentrations were decreased, SO2 concentrations at half of the AQMSs (11/25) did not show a significant change. There were stations at which higher pollutant concentrations were measured in the study period in 2020 compared to that of 2019. Excess risks associated with PM2.5 and PM10 were estimated to be variable, albeit with a small difference. In conclusion, the heterogeneous actions taken in response to the COVID-19 pandemic resulted in mixed effects on ambient air quality.
  • Editorial
    Special Issue on the 4th International Conference on Recycling and Reuse 24–26 October 2018, Istanbul, Turkey: Preface
    (Elsevier B.V., 2019) Okten, H.E.; Ökten, Hatice Eser; Balkaya, N.; Aydin, S.; Elmaslar, E.; Ongen, A.; Selcuk, H.
    [No abstract available]