Environmental Engineering / Çevre Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/4321
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Article Pomza ve Nsdd-pomza ile Sabit Yataklı Kolon Reaktörde Metilen Mavisi Giderimi: Deneysel ve Modelleme Çalışması(2019) Balcı, Esin; Ökten, Hatice Eser; Genişoğlu, Mesut; Recepoğlu, Yaşar Kemal; Gören, Ayşegül YağmurNano sıfır değerlikli demir (nSDD) yüksek renk konsantrasyonlarına sahip tekstil atıksularının arıtımında ekonomik ve çevre dostu bir adsorban olarak ortaya çıkmaktadır. Ancak nSDD partikülleri sulu çözeltilerde elektrostatik etkileşimler sebebiyle kolayca topaklaşmakta ve bu da arıtma veriminin düşmesine neden olmaktadır. Dolayısıyla düşük maliyetli, doğal poröz yapıda ve ortalama 2m2/gr spesifik yüzey alanına sahip pomza, nSDD topaklaşmasını önleyici bir malzeme olarak kullanılabilir. Bu çalışmada sadece pomza ve pomzanSDD (ağırlıkça 9:1) karışımının kullanıldığı kolon reaktörde 25, 50, 75 ve 100 mg/L metilen mavisi konsantrasyonları için arıtma verimleri incelenmiştir. Pomzanın ve pomza-nSDD karışımının 100 mg/L metilen mavisi deneyindeki toplam kapasiteleri sırasıyla 2,8 ve 4,2 mg/g-adsorban olarak bulunmuştur. Özellikle düşük konsantrasyonlarda, pomza-nSDD karışımının arıtma performansını önemli ölçüde arttırdığı görülmüştür. Thomas modeli deneysel verilere uygulanmış ve modelin öngörü gücünün düşük konsantrasyonda yüksekken, yüksek konsantrasyonlarda ortalama olduğu kanısına varılmıştır.Book Part Arsenic Removal by Electrocoagulation(Wiley, 2022) Gören, Ayşegül Yağmur; Kobya, MehmetBecause of the toxic impacts on human health, the arsenic (As) limit value in drinking water was decreased from 50 to 10 ?g l-1 by the relevant authorities (WHO 1993; US EPA 2001). In this case, the problem of As pollution in natural water resources used for drinking water has grown even more and turned into a global crisis. According to reports in many parts of the world, over about 230 million people appear to be affected by high arsenic concentrations in groundwater. In this case, it turned out that there was a great need for cost-effective and environmentally friendly technologies from drinking water sources. One of the emerging water treatment technologies in recent years is electrocoagulation (EC) and it has been seen that it is effective in treating As (>99%) from water and eliminates some of the disadvantages of other conventional treatment processes. EC method includes electro-oxidation of anode electrode materials (iron and aluminum) and in situ production of coagulant agents. From groundwater resources with As content of 5-1000 ?g l-1, As removal efficiencies and operating costs (OCS) of EC technology using iron (Fe) and aluminum (Al) anodes were 85.0-99.9% and 0.0020-1.04 US$ m-3, respectively. Different types (plate, scrap, rod, and ball) of electrodes were used for As removal with the EC process, and it was observed that Fe electrodes or Fe-Al hybrid electrodes performed better in As removal. In addition, it has been determined that arsenate (As(V)) removal is more effective than arsenite (As(III)). A significant quantity of As(III) is oxidized in the EC process, resulting in precipitation, adsorption, and metal-oxy hydroxylic complex reactions. EC process has a lower OC to achieve As removal below the permissible WHO value compared to conventional treatment processes, accomplishing it as a further applicable option for As removal. © 2023 John Wiley & Sons, Inc.Book Part Citation - Scopus: 32Language of Response Surface Methodology as an Experimental Strategy for Electrochemical Wastewater Treatment Process Optimization(Elsevier, 2022) Gören, Ayşegül Yağmur; Recepoğlu, Yaşar Kemal; Khataee, AlirezaThe availability and accessibility to safe and secure water resources are the key technological and scientific concerns of global significance. As a result of water scarcity worldwide, wastewater treatment and reuse are considered viable options to replace freshwater resources in agricultural irrigation and domestic and industrial purposes. A significant need for clean water has promoted the invention and/or enhancement of several electrochemical wastewater treatment (EWT) processes. Optimization of the process variables plays a crucial role in wastewater treatment to enhance technology performance, considering removal efficiency, operating cost, and environmental impacts. These processes are fundamentally complex multivariable, and the optimization through conventional methods is unreliable, inflexible, and time- and material-consuming. In this perspective, response surface methodology (RSM) appears to be a beneficial statistical experimental strategy for the performance optimization of the EWT process. This model could be utilized for the optimization and analysis of the individual and/or combined effects of operational variables on the treatment process to improve the system performance. Furthermore, this model provides a number of information from a slight number of experimental trials. In this chapter, a summary and a discussion are presented on the RSM model used in the electrochemical wastewater treatment processes to overcome process crucial challenges toward the optimization and modeling of process parameters. It provides a potential model to enhance the various types of wastewater treatment process performance with effective optimization. Overall, it is described that the RSM model can be used in EWT processes to find the optimum conditions.Article Citation - WoS: 9Citation - Scopus: 9How Does Arsenic Speciation (arsenite and Arsenate) in Groundwater Affect the Performance of an Aerated Electrocoagulation Reactor and Human Health Risk?(Elsevier, 2022) Gören, Ayşegül Yağmur; Kobya, Mehmet; Khataee, AlirezaArsenic (As) occurrence in water resources has become one of the most critical environmental problems worldwide. The detrimental health impacts on humans have been reported due to the consumption of As-contaminated groundwater resources. Consumption of As-containing water over the long term can cause arsenicosis and chronic effects on human health due to its toxicity. Several treatment processes are available for As removals such as coagulation, ion exchange, adsorption, and membrane technologies but they have various major drawbacks. In the present work, therefore, an aerated electrocoagulation (EC) system with aluminum anodes was operated for simultaneous arsenate (As(V)) and arsenite (As(III)) removal to overcome the disadvantages of other processes such as, sludge formation, difficulties in operation, high operating costs, high energy consumption, and the requirement of pre-treatment process and to enhance the conventional EC process. The combined effects of the applied current (0.075–0.3 A), aeration rate (0–6 L/min), pH (6.5–8.5), and As speciation (As(V)-As(III)) were studied on As removal efficiency. The findings revealed that As removal mostly depended on the airflow rate and the applied current in the EC system. The highest As removal efficiency (99.1%) was obtained at an airflow rate of 6 L/min, a pH of 6.5, an initial As (V) concentration of 200 μg/L, and a current of 0.3 A, with an energy consumption of 2.85 kWh/m3 and an operating cost of 0.66 $/m3. The human health risk assessment of treated water was also examined to understand the performance of the EC system. At most of the experimental runs, the chronic toxic risk (CTR) and carcinogenic risk (CR) of As were within the permissible limits except for an airflow rate of 0–2 L/min, an initial pH of 8.5, and a current of 0.075–0.15 A for high initial As (III) concentrations. Overall, the As removal performance and groundwater risk assessment show that the EC process is a promising option for industrial applications.Article Phytoremediation of Boron Containing Synthetic Aqueous Solutions and Real Geothermal Water Using Lemna Minor(2021) Ökten, Hatice Eser; Gören, Ayşegül YağmurIn 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: 1Arsenate Removal From Groundwater by Air-Injected Ec With Al Ball Anodes: Effects of Operational Parameters(Pamukkale Üniversitesi, 2020) Gören, Ayşegül Yağmur; Öncel, Mehmet Salim; Kobya, MehmetTreatment of arsenate from groundwater by electrocoagulation (EC) reactor with air supply unit using Al ball electrodes were studied in this paper. Influence of some operating variables, for instance, applied current (0.075-0.3 A), initial pH (5.5-8.5), air flow rate (0-6 L/min), size of Al ball electrodes (5-10 mm), and height of electrode in EC reactor (2-8 cm) on the As(V) removal efficiency were evaluated. The As (V) removal efficiency increased with the increment of applied current, air flow, electrode altitude in EC reactor, and EC time while its removal efficiency decreased with the increment of size of Al ball electrodes. The maximum As(V) removal percentage, minimum operating cost and energy consumption were found as 98.68 %, 0.609 $/$m^3$ and 3.7694 kWh/$m^3$ at pH of 7.5, current density of 0.30 A, size of Al balls of 7.5 mm, height of electrode in EC of 5 c†m, and air flow rate of 6 L/min, respectivelyArticle Citation - Scopus: 5Effect 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 CemilThe 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.Article Methylene Blue Removal of Fixed-Bed Column Reactor With Pumice and Nzvi-Pumice: Experimental and Modeling Study(Süleyman Demirel Üniversitesi, 2019) Genişoğlu, Mesut; Gören, Ayşegül Yağmur; Balcı, Esin; Recepoğlu, Yaşar Kemal; Ökten, Hatice EserNano zero-valent iron (nZVI) emerges as a low cost and eco-friendly adsorbent to treat textile wastewater, which is rich in dye content. However nZVI particles can easily agglomerate in aqueous environment due to electrostatic interaction, decreasing their treatment efficiency. Therefore pumice, a low-cost and naturally found porous material with lower specific surface area (2m2/gr), can be used as support material to reduce agglomeration of nZVI. Treatment efficiencies of pumice/nZVI packing (10:0 and 9:1 (w/w)) in column reactor for specified initial methylene blue concentrations (25, 50, 75 and 100 mg/L) were investigated in this study. Adsorption capacities of the adsorbents were calculated as 2.8 and 4.2 mg/g-adsorbent, respectively at 100 mg/L initial methylene blue concentration. Mixed bed column performed significantly better than its pumice-only counterpart for low initial concentrations. Thomas adsorption model was applied to experimental results with a moderate to high predictive power.Conference Object Groundwater Pollution by Nitrate From Agricultural Fertilizers: the Case of Menemen Basin (aegean Region, Turkey)(İZSU, 2017) Gören, Ayşegül Yağmur; Genişoğlu, Mesut; Balcı, Esin; Ökten, Hatice Eser; Baba, AlperGroundwater is an essential drinking water source in Menemen subbasin of İzmir city, Turkey. The aim of this study was to investigate the groundwater contamination by nitrates of agricultural lands. For this purpose, we evaluated variations of groundwater pH, redox potential, electrical conductivity (EC), major anions (NO3, Cl, SO4, HCO3 and CO3) and cations (Na, K, Ca and Mg). A statistical correlation procedure and piper diagram for hydrogeochemistry of groundwater were also applied. Nitrate levels were found to be higher around agricultural areas. Also EC values and Cl were measured to be higher as proximity to coastal areas increased, indicating seawater intrusion. Agricultural activities and excessive freshwater withdrawal were shown to impair groundwater quality and quantity at Menemen subbasin.