Environmental Engineering / Çevre Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/4321
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Article Citation - WoS: 12Citation - Scopus: 14Identifying Geogenic and Anthropogenic Aluminum Pollution on Different Spatial Distributions and Removal of Natural Waters and Soil in Çanakkale, Turkey(Amer Chemical Soc, 2023) Hızlı, Sezin; Koraoğlu, Aybike Gül; Gören, Ayşegül Yağmur; Kobya, MehmetThe Canakkale-Kirazli region (Turkey) is enriched with minerals, especially aluminum (Al), which dangerously get transported into aquatic media due to several mining and geological activities in recent years. In this study, Al and other potentially toxic metals (PTMs) including B, Ba, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Si, and Zn, in both water and soil samples, were measured for quality determination. Selected metals were also analyzed by the enrichment factor (EF), the geoaccumulation index (I-geo), the contamination factor (CF), and the pollution load index (PLI) to evaluate both water and soil pollution geogenically or anthropogenically. Also, the metals were clustered to support the pollution source with Pearson's correlation, principal component analysis (PCA), and hierarchical cluster analysis (HCA). Forty-five natural water samples and 12 soil samples were collected spatially. To perform pollution assessment, two fundamental treatment processes to remove Al pollution from the sample including the highest Al concentration (38.38 mg/L) in water were applied: (1) precipitation with pH adjustment and (2) removal with ion exchange. The pH values of water samples were changed in the range of 3-9 to test the dissolution of Al. The results demonstrated that the study area was mostly under the influence of geogenic aluminum pollution.Article Citation - WoS: 8Citation - Scopus: 8Removal of Arsenic in Groundwater From Western Anatolia, Turkey Using an Electrocoagulation Reactor With Different Types of Iron Anodes(Elsevier, 2022) Kobya, Mehmet; Dolaz, Mustafa; Özaydın Şenol, Burcu; Gören, Ayşegül YağmurElectrocoagulation (EC) is a significantly efficient method for As removal from waters and received considerable attention recently. In this study, the natural groundwater (GW) samples containing As concentrations of GW-1: 538.8 μg L−1, GW-2: 1132.1 μg L−1, and GW-3: 52, 000 μg L−1 were obtained from different provinces and treated by EC process using different iron anodes (plate, ball, and scrap). To achieve drinking water As standard (10 μg L−1), the operational time, applied current, and As removal optimization for all anode types were studied. At applied current of 0.025 A, the As removal efficiency, EC time, and operating cost were >99.9%, 180 min and 0.406 $ m−3 for ball anodes, >99.9%, 100 min and 0.0813 $ m−3 for plate anodes, >99.9%, 80 min and 0.0815 $ m−3 for scrap anodes for GW-3, respectively. It was observed that as the As concentration in the GW increased, the EC time and operating cost increased. Overall, it was concluded that Fe scrap anodes are more advantageous than other types of anodes in terms of operating cost in EC reactor for As removal.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 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 - WoS: 47Citation - Scopus: 57Arsenic Removal From Groundwater Using an Aerated Electrocoagulation Reactor With 3d Al Electrodes in the Presence of Anions(Elsevier, 2021) Gören, Ayşegül Yağmur; Kobya, MehmetCo-occurrence of arsenic and anions in groundwater causes a severe health problems and combine effects of these pollutants significantly affect performance of treatment process. Thus, this study has been conducted to examine the combine effects of anions on arsenic removal using aerated electrocoagulation (EC) reactor with 3D Al electrodes in groundwater. A 3-level, six factors Box-Behnken experimental design (BBD) was applied to investigate the individual and combine effect of anions and operating time: phosphate (x1: 1–10 mg L?1), silica (x2: 20–80 mg L?1), bicarbonate (x3: 130–670 mg L?1), fluoride (x4: 2–10 mg L?1), boron (x5: 5–10 mg L?1), and operating time (x6: 8–22 min) on desired responses. The specified responses were effluent arsenic concentration (Cf,As), removal efficiency of arsenic (Re), consumptions of energy and electrode (ENC and ELC), operational cost (OC), and adsorption capacity (qe). The optimum operating parameters predicted using BBD were found to be x1: 1.0 mg L?1, x2: 26.0 mg L?1, x3: 651.5 mg L?1, x4: 2.0 mg L?1, x5: 9.9 mg L?1, and x6: 10.5 min considering highest removal efficiency of arsenic and lowest operational cost. Under these operating conditions, the experimental values of Cf,As, Re, ENC, ELC, OC, and qe were found to be 2.82 ?g L?1, 98.6%, 0.411 kWh m?3, 0.0124 kg m?3, 0.098 $ m?3, and 17.65 ?g As (mg Al)?1, respectively. Furthermore, mathematical modelling was conducted using quadratic regression model and response surface analysis was performed to understand the relationship between independent parameters and responses. © 2020 Elsevier LtdArticle Citation - WoS: 10Citation - Scopus: 12Removal of Arsenate by Electrocoagulation Reactor Using Aluminum Ball Anode Electrodes(IWA Publishing, 2018) Gören, Ayşegül Yağmur; Öncel, Mehmet Salim; Demirbaş, Erhan; Şık, Emrah; Kobya, MehmetThe aim of this research was to remove arsenate (As(V)) from groundwater using an air-injected electrocoagulation (EC) reactor with aluminum (Al) ball anodes. The effects of seven operating variables - initial pH, applied current (i), operating time (t(EC)), initial As(V) concentration (C-o), Al ball anode diameter (d(p)), reactor column height (h), and airflow rate (Q(air)) were investigated with a Box-Behnken statistical experimental design. ANOVA results from the quadratic model equations indicated that the model fitted very well with the experimental data for the responses, which were removal efficiency, operating cost (OC), As(V) adsorption capacity, and effluent concentration (R-2 >= 0.87). The most effective parameters were applied current, operating time, and anode height for As(V) removal efficiency in the EC reactor, while initial pH, Al anode diameter, and air flow rate had limited effect on removal. The model predicted a residual As(V) concentration below 10 mu g/L under the optimum operating conditions (pH 7.03, 0.29 A, 10.5 min, d(p) 7.5 mm, 613.4 mu g/L, h 5.1 cm, and Q(air) 6.4 L/min). The maximum As(V) removal efficiency and minimum OC in the EC process were almost 99% and 0.442 $/m(3), respectively.Article Citation - WoS: 26Citation - Scopus: 34Arsenite Removal From Groundwater in a Batch Electrocoagulation Process: Optimization Through Response Surface Methodology(Taylor & Francis, 2019) Şık, Emrah; Gören, Ayşegül Yağmur; Demirbaş, Erhan; Kobya, Mehmet; Öncel, Mehmet SalimIn this study, influences of seven process variables such as initial pH (pH(i)), applied current (i), operating time (t(EC)), initial As(III) concentration (C-o), diameter of Fe ball anode (d(p)), column height in the electrocoagulation (EC) reactor (h) and airflow rate (Q(air)) for removal of As(III) from groundwater by a new air-fed fixed-bed EC reactor were evaluated with a response surface methodology (RSM). The proposed quadratic model fitted very well with the experimental data for the responses. The removal efficiencies and operating costs were determined to be 99% and 0.01 $/m(3) at the optimum operating conditions (a pH(i) of 8.5, 0.05 A, 4.94 min, d(p) of 9.24 mm, h of 7.49 cm, Q(air) of 9.98 L/min for 50 mu g/L). This study clearly showed that the RSM in the EC process was a very suitable method to optimize the operating conditions at the target value of effluent As(III) concentration (10 mu g/L) while keeping the operating cost to minimal and maximize the removal efficiency.Article Citation - WoS: 4Citation - Scopus: 5Combined Influence of Some Cations on Arsenic Removal by an Air-Injection Ec Reactor Using Aluminum Ball Electrodes(Desalination Publications, 2020) Gören, Ayşegül Yağmur; Kobya, Mehmet; Şık, Emrah; Demirbaş, Erhan; Öncel, Mehmet SalimCombined effects of some cations such as calcium (Ca2+), iron (Fe2+), manganese (Mn2+), and magnesium (Mg2+) and operating time on the removal of arsenic by air-injected electrocoagulation (EC) reactor with aluminum (Al) ball electrodes were investigated. The operating conditions were optimized with the Box-Behnken design of response surface methodology (RSM). The response variables were selected from the program as removal efficiency, residual arsenic concentration, energy consumption and operating cost (OC) in the EC process. A total of 46 experimental run was performed. The removal efficiency of arsenic increased with an increase in iron concentration (0.5-4.5 mg/L). The rest of the cations showed no noticeable effect on arsenic removal efficiency. The maximum arsenic removal efficiency and minimum OC at the optimum operating conditions (C-Ca: 305 mg/L, C-Mg: 42 mg/L, C-Fe: 3.3 mg/L, C-Mn: 2.34 mg/L, initial pH of 7.5 applied current of 0.15 A, Al ball size of 7.5 mm, 5.0 cm of Al ball anodes height in the EC reactor, air-fed rate of 6.0 L/min and t(EC): 16.83 min) in the EC process were 99.9% and 0.0332 $/m(3) for initial arsenic concentration of 200 mu g/L, respectively. The removal mechanism of As(III) by EC seems to be oxidation of As(III) to As(V) and subsequent removal by adsorption/complexation with aluminum hydroxides generated in the process. The results showed that the air-injected EC reactor can be used effectively for arsenic and hardness removal simultaneously from real groundwater sources.Article Citation - WoS: 37Citation - Scopus: 40Arsenite Removal From Groundwater by Aerated Electrocoagulation Reactor With Al Ball Electrodes: Human Health Risk Assessment(Elsevier, 2020) Gören, Ayşegül Yağmur; Kobya, Mehmet; Öncel, Mehmet SalimThe application of conventional electrocoagulation (EC) process for removal of As(III) from groundwater suffers from the need of external oxidation agent for oxidation of As(III) to As(V). To tackle this limitation, an aerated EC reactor for the removal of As(III) from groundwater was evaluated in this study. The effect of initial pH(i), air flow rate, applied current, and electrode height in the EC reactor was examined. The experimental results showed that removal of arsenic mostly dependent on the applied current, electrode height in EC reactor, and air flow rate. The As(III) removal efficiency (99.2%) was maximum at pH(i) of 7.5, air flow rate of 6 L min(-1), applied current of 0.30 A, and electrode height in EC reactor of 5 cm, with an total operating cost of 0.583 $ m(-3). Furthermore, the carcinogenic risk (CR) and non-carcinogenic risk of arsenic (As) was in the range of tolerable limits at all operating conditions except applied current of 0.075 A at the end of the aerated EC process to remove As from groundwater. The present EC reactor process is able to remove As(III) from groundwater to below 10 mu g L-1, which is maximum contaminant level of arsenic in drinking water according to the World Health Organization (WHO). (C) 2020 Elsevier Ltd. All rights reserved.Article Citation - WoS: 3Citation - Scopus: 6Optimization of Some Cations for Removal of Arsenic From Groundwater by Electrocoagulation Process(Gheorghe Asachi Technical University of Iasi, 2018) Kobya, Mehmet; Şık, Emrah; Demirbaş, Erhan; Gören, Ayşegül Yağmur; Öncel, Mehmet SalimThis study dealt with investigation of arsenic removal from groundwater using electrocoagulation (EC) method in a batch mode by the Box-Behnken experimental design method. Effects of some cations like Ca, Fe, Mg, Mn and operating time on the removal were explored by an air injected EC reactor. The combined effects of these variables were analyzed by the quadratic model for predicting the highest removal efficiency of arsenic from groundwater. The arsenic removal efficiency was found to be dependent on increase with operating time and concentrations of Ca, Mg, Fe and lower concentration of Mn. When operating variables were considered as minimum operating cost and maximum removal efficiency, the optimum operating parameters were determined to be 132 mg/L of CCa, 55 mg/L of CMg, 4.5 mg /L of CFe, 4.5 mg/L of CMn and operating time of 3 min to meet the target concentration of <10 μg/L. Values of removal efficiency and operating cost at the optimum conditions were 95.1% and 0.041 $/m3.