Yazarlar
- Kul, Sinan(13)
- Yıldırım, Ümit(9)
- Duran, Celal(6)
- Serencam, Huseyin(6)
- Ekmekyapar Torun, Fatma(5)
- Eryılmaz Türkkan, Gökçen(5)
- Güven, Onur(5)
- Kurt, Mehmet Ali(5)
- Ozdes, Duygu(5)
- Cengiz, Ibrahim(4)
- Torun, Fatma Ekmekyapar(4)
- İrdemez, Şahset(4)
- Bingül, Züleyha(3)
- Boncukcuoğlu, Recep(3)
- Guler, Cuneyt(3)
- Hırca, Tuğçe(3)
- Jomaa, Seifeddine(3)
- Niazkar, Majid(3)
- Nuhoglu, Alper(3)
- Nuhoğlu, Alper(3)
- Serencam, Hüseyin(3)
- Teke, Çağatay(3)
- Tufekci, Mehmet(3)
- Uçurum, Metin(3)
- Yildiz, Ergun(3)
- Özdemir, Akın(3)
- Celebi, Neslihan(2)
- Cengiz, İbrahim(2)
- Degermenci, Nejdet(2)
- Demircioğlu, Nuhi(2)
- Gundogdu, Ali(2)
- Güler, Cüneyt(2)
- Kalkan, Ekrem(2)
- Karakaş, İbrahim Hakkı(2)
- Karcioğlu Karakaş, Zeynep(2)
- Korkmaz, Serdar(2)
- Korkmaz, Serol(2)
- Kul, S.(2)
- Nadaroglu, Hayrunnisa(2)
- Reçber, Züleyha(2)
Yayınlar
- MakaleAçık Erişim2022Scopus SJRQ3DETERMINATION OF PARAMETERS AFFECTING KINETIC AND THERMODYNAMIC VALUES FOR LEAD REMOVAL USING WASTEWATER TREATMENT PLANT SEWAGE SLUDGE ASH
Irdemez, Sahset; Yesilyurt, Duygu; Torun, Fatma Ekmekyapar; Kul, Sinan
In this study, treatment of lead containing wastewater using sewage sludge ash obtained from the incineration unit in the domestic wastewater treatment plant in Gaziantep province in Turkey was investigated. The main purpose of the study is to determine the potential of using the treatment sludge ash, which comes out as waste in the treatment plant, in the treatment of wastewater of another industry. As a result of this study, the most suitable adsorption conditions were determined and focused on the kinetics of adsorption. In the experiments, the lead adsorption capacity of sewage sludge ash was determined as 122 mg g-1 at 0.5 g L-1 adsorbent concentration in wastewater containing 100 mg L-1 Pb2+under optimum conditions. As a result of the research, it was determined that the adsorption reaction proceeds according to the pseudo second degree reaction and is suitable for the Langmuir isotherm. As thermodynamic constants, & UDelta;H & DEG; = 7.407 kJ mol-1 and & UDelta;S & DEG; = 33.25 J mol-1 were determined. As a result of this, it was determined that the adsorption reaction was endothermic, spontaneous and random, and adsorption was physical adsorption. The results show that sewage sludge ash can be used in the treatment of water containing high concentrations of Pb2+.
AtıfWoS3OpenAlex4
İncele - MakaleAçık Erişim2022Scopus SJRQ2The Investigation of COD Treatment and Energy Consumption of Urban Wastewater by a Continuous Electrocoagulation System
Dede Sağsöz, Yeşim; Yilmaz, Alper Erdem; Ekmekyapar Torun, Fatma; Kocadağistan, Beyhan; Kul, Sinan
In this study, electrochemical treatment of urban wastewater with electrical conductivity of 1000 µS cm-1 and chemical oxygen demand of 250 mg L-1 was investigated using the variables of initial pH value, current density and flow rate. Electrocoagulation was used, in which aluminum and stainless steel were selected, as the electrochemical treatment process. The electrocoagulation process was operated in continuous mode. The data obtained in experimental studies show that the best COD removal efficiency occurred in experiments where the initial pH value was 6. The increase in current density from 5 A to 15 A decreased the removal efficiency from 79 to 67%. The increase in flow rate under constant current density also reduced the efficiency of removal as expected. In experiments in which current density and flow rate were examined together, the increase in flow rate allowed the application of higher current densities. This situation led to considerable reductions in energy consumption values, even if the COD removal efficiency did not significantly increase. The high COD removal obtained with the use of high flow rate and high current density indicates that the electrocoagulation process can be used for high flow rate municipal wastewater treatment.
AtıfScopus6WoS5OpenAlex5
İncele - MakaleAçık Erişim2022Scopus SJRQ3A Two-Stage ORC Integration to an Existing Fluidized Bed Sewage Sludge Incineration Plant for Power Production in the Scope of Waste-to-Energy
Abusoglu, A.; Tozlu, A.; Anvari-Moghaddam, A.
This paper presents the design, evaluation, and optimization of an electricity generation system based on the two-stage organic Rankine cycle (TS-ORC), which utilizes the waste heat of an existing fluidized bed sewage sludge incineration (FBSSI) facility. The facility incinerates an average of 300 tons per day of sewage sludge with a dry matter content of 22%. After the drying process, the sewage sludge is burned in a fluidized bed combustor, and exhaust gas at a temperature of about 850-900ºC is released due to the combustion. The system provides the energy required to dry the sludge from this exhaust gas. In this study, a TS-ORC is designed to be coupled to the exhaust gas flowlines discharged to the atmosphere at two different points in the FBSSI plant. The exergy efficiency of the FBSSI facility is found to be 70.5%. Three different working fluids are selected to examine the variations of thermodynamic and thermoeconomic performance parameters of the designed TS-ORC system. The highest power generation in the TS-ORC system (183.40 kW) is achieved using R1234yf as working fluid. R1234yf is also the most expensive fluid for electricity generation among the other working fluids (10.57 $/h). The least electricity generation in the TS-ORC (142.70 kW) occurs at the thermoeconomically most affordable cost with R245fa (9.35 $/h).
AtıfScopus2WoS2OpenAlex2İncele - MakaleAçık Erişim2022Scopus SJRQ2Investigation of the biological treatability of pistachio processing industry wastewaters in a batch-operated aerobic bioreactor
Tırınk, Sevtap; Nuhoğlu, Alper; Kul, Sinan
This study encompasses investigation of treatment of pistachio processing industry wastewaters in a batch reactor under aerobic conditions, calculation of kinetic parameters and comparison of different inhibition models. The mixed microorganism culture used in the study was adapted to pistachio processing industry wastewaters for nearly one month and then concentrations from 50 to 1000 mg L−1 of pistachio processing industry wastewaters were added to the medium and treatment was investigated in batch experiments. The Andrews, Han-Levenspiel, Luong and Aiba biokinetic equations were chosen for the correlations between the concentration of pistachio processing industry wastewaters and specific growth rates, and the kinetic parameters in these biokinetic equations were calculated. The maximum specific growh rate, semi-saturated constant and inhibition constant parameters, included in the Aiba biokinetic equation providing best fit among the other equations, had values calculated as 0.25 h−1, 19 mg L−1, and 516 mg L−1, respectively. The substrate value reaches maximum value and the specific growth rate at this concentration were calculated as 101.379 mg L−1 and 0.1827 h−1, respectively. Graphical abstract: [Figure not available: see fulltext.]
AtıfScopus4WoS4OpenAlex5
İncele - MakaleAçık Erişim2022Scopus SJRQ3Investigation of the recovery efficiency of CeUF method through RT-qPCR quantification of inactivated SARS-CoV-2 in untreated wastewater
Sait, Ahmet; Korkmaz, Serol; Parmaksiz, Ayse; Bayraktar, Bulent
Wastewater-based disease monitoring is an early warning system and a surveillance tool for infectious disease outbreaks regarding pathogens with pandemic potential. This study aimed at investigating the recovery efficiency of centrifugal ultrafiltration (CeUF), which is one of the most-used virus concentration methods, for inactive severe acute respiratory syndrome coronavi-rus 2 (SARS-CoV-2) added to wastewater. Inactivated SARS-CoV-2 was inoculated into untreated wastewater at different concentrations (4 × 103, 8 × 103, 16 × 103, 24 × 103 and 32 × 103 gene copy/ µL) and concentrated through ultrafiltration with a disposable centrifugal filter device. Total nucleic acids in concentrated filtrates were extracted and isolated by an automated system. In isolates, total RNA was measured by a UV/VIS spectrophotometer, and the recovered virus was quanti-fied by RT-qPCR with two gene regions (N1 and N2). The recovery rates were between 11% and 17.8% (mean 15.1%, CV below 15%). While there were positive correlations among the inoculated virus, total RNA and recovered virus, there was no correlation and linearity between the recovery rates. Despite limited recovery rates, CeUF integrated with RT-qPCR quantification can be a valid assay for monitoring SARS-CoV-2 in wastewater, and an early warning system.
AtıfScopus2WoS2OpenAlex3İncele - MakaleAçık Erişim2022Scopus SJRQ1Assessment of Climate Change Impact on Discharge of the Lakhmass Catchment (Northwest Tunisia)
Ben Nsir, Siwar; Jomaa, Seifeddine; Yıldırım, Ümit; Zhou, Xiangqian; D’Oria, Marco; Rode, Michael; Khlifi, Slaheddine
The Mediterranean region is increasingly recognized as a climate change hotspot but is highly underrepresented in hydrological climate change studies. This study aims to investigate the climate change effects on the hydrology of Lakhmass catchment in Tunisia. Lakhmass catchment is a part of the Medium Valley of Medjerda in northwestern Tunisia that drains an area of 126 km². First, the Hydrologiska Byråns Vattenbalansavdelning light (HBV-light) model was calibrated and validated successfully at a daily time step to simulate discharge during the 1981–1986 period. The Nash Sutcliffe Efficiency and Percent bias (NSE, PBIAS) were (0.80, +2.0%) and (0.53, −9.5%) for calibration (September 1982–August 1984) and validation (September 1984–August 1986) periods, respectively. Second, HBV-light model was considered as a predictive tool to simulate discharge in a baseline period (1981–2009) and future projections using data (precipitation and temperature) from thirteen combinations of General Circulation Models (GCMs) and Regional Climatic Models (RCMs). We used two trajectories of Representative Concentration Pathways, RCP4.5 and RCP8.5, suggested by the Intergovernmental Panel on Climate Change (IPCC). Each RCP is divided into three projection periods: near-term (2010–2039), mid-term (2040–2069) and long-term (2070–2099). For both scenarios, a decrease in precipitation and discharge will be expected with an increase in air temperature and a reduction in precipitation with almost 5% for every +1 °C of global warming. By long-term (2070–2099) projection period, results suggested an increase in temperature with about 2.7 °C and 4 °C, and a decrease in precipitation of approximately 7.5% and 15% under RCP4.5 and RCP8.5, respectively. This will likely result in a reduction of discharge of 12.5% and 36.6% under RCP4.5 and RCP8.5, respectively. This situation calls for early climate change adaptation measures under a participatory approach, including multiple stakeholders and water users.
AtıfScopus11WoS11OpenAlex14İncele - MakaleYalnız künye2022Scopus SJRQ2Investigation of the Treatment of Olive Mill Wastewater by Electrooxidation
Kul, Sinan; Boncukcuoğlu, Recep; Ekmekyapar Torun, Fatma; Reçber, Züleyha; Sözüdoğru, Onur; Aladağ, Erdinç
The electrooxidation process, one of the advanced oxidation processes, is one of the effective treatment processes used in treating various industrial wastewaters. This study investigated the treatment of olive mill wastewater using the electrooxidation process. This study includes the effects of different experimental parameters on chemical oxygen demand and total phenol removal efficiencies in olive mill wastewater. Ti/IrO2/RuO2 mesh plates as anode material and Ti mesh plates as cathode material were used in the study. The effects of stirring rate, dilution factor, pH, type of support electrolyte, the concentration of support electrolyte, and current density on chemical oxygen demand and total phenol removal efficiencies were examined in the experiments using a batch reactor. The study found that the chemical oxygen demand and total phenol removal rates were 96.93% and 100% under optimum conditions, respectively. According to the treatment data obtained, it can be said that olive mill wastewater can be treated by the electrooxidation method and can be proposed as a pretreatment system before entering biological treatment.
AtıfScopus8WoS6OpenAlex8İncele - MakaleYalnız künye2022Scopus SJRQ2Applications of innovative polygonal trend analyses to precipitation series of Eastern Black Sea Basin, Turkey
Hırca, Tuğçe; Eryılmaz Türkkan, Gökçen; Niazkar, Majid
Examining historical variations of hydroclimatic variables can provide crucial information about changes of water resources in a water cycle. In this study, the Mann–Kendall (MK) and Innovative Polygon Trend Analysis (IPTA) methods were applied to 56-year precipitation data collected at 8 measuring stations. These stations are located in Eastern Black Sea Basin (EBSB), which has a significant amount of annual precipitation and hydroelectric potential in Turkey. This study has two objectives: (1) investigating possible changes in the monthly precipitation and (2) comparing the results achieved by a classical (MK) and one of the latest trend analysis methods presented in the literature (IPTA). Based on the results, MK achieved no trend for most of months, while it reached an increasing trend for March at most of the stations. Likewise, IPTA determined an increasing trend for March precipitation. However, an increasing/decreasing trend was obtained by IPTA for most of the months and stations. In other words, comparing the trend analysis results obtained by IPTA and MK indicates a significant discrepancy between the numbers of months with detected trends primarily because the former is relatively more sensitive in trend identification. To be more precise, IPTA and MK determined trends in approximately 81.25% and 12.5% of all months, respectively. Furthermore, the former identified quite the same trends in every month which the latter reported a trend. Moreover, the polygon of the mean and standard deviation graphs developed by IPTA provides a year cycle, which brings about useful information for water utility sectors and decision makers of the study area. Finally, the findings of this study contribute to a large amount of research that attempts to explore spatio-temporal variations of hydroclimatic variables around the globe not only to enhance humans’ knowledge about changes in a water cycle but also assess climate change impacts.
AtıfScopus54WoS50OpenAlex64İncele - MakaleAçık Erişim2022Scopus SJRQ3Comparison of Bomaplex Blue CR-L Removal by Adsorption Using Raw and Activated Pumpkin Seed Shells
Irdemez, Şahset; Özyay, Gizem; Ekmekyapar Torun, Fatma; Kul, Sinan; Bingül, Züleyha
In this study, removal of colour from wastewaters prepared synthetically using Bomaplex Blue CR-L was investigated using raw and activated pumpkin seed shells by adsorption in a batch system. The effects of stirring speed, adsorbent concentration, dye concentration, temperature and pH on colour removal were investigated, and adsorption capacities of raw and activated pumpkin seed shells were determined. In addition, adsorption kinetics, isotherm coefficients, activation energies and thermodynamic parameters were calculated. The optimal adsorption conditions were determined as pH = 2, stirring speed of 200 rpm, adsorbent concentration of 10 g L-1 and 30 °C. Under the optimal conditions, the maximum removal efficiency of Bomaplex Blue CR-L using raw pumpkin seed shells was 73.01 %. This value rose to 79.71 % after activation processing was applied. Experimental adsorption data show that the adsorption is more suited to the Langmuir adsorption model and works in accordance with the pseudo-first-order kinetics model. As a result of thermodynamic research, ΔH° and ΔS° were 31.515 kJ mol-1 and 109.952 kJ mol-1 K-1 for the raw adsorbent, respectively. For the activated adsorbent, ΔH° and ΔS° were 43.118 kJ mol-1 and 152.237 kJ mol-1 K-1, respectively. The activation energy of adsorption was calculated as 10.918 kJ mol-1 for the raw adsorbent and 9.882 kJ mol-1 for the activated adsorbent.
AtıfScopus9WoS7OpenAlex9İncele - MakaleYalnız künye2022Scopus SJRQ3Investigation of Manganese Ion Removal from Waters Using Sewage Sludge Ash
Şahset, İrdemez; Duygu, Yeşılyurt; Torun, Ekmekyapar; Fatma; Sinan, Kul; Züleyha, Bıngül
In this study, the removal of Mn2+ ions from waters by the adsorption method using ash obtained from a treatment plant sludge burning unit, which is treatment plant waste and mostly disposed of in a landfill, was investigated. By determining the most suitable conditions for adsorption, adsorption kinetics, isotherms, and thermodynamic values were determined. In the experiments, 63.9% removal efficiency was achieved using 10 g/L adsorbent concentration for 10 mg/L Mn+2 under optimum conditions. As a result of the research, it was determined that the adsorption proceeds according to the pseudo-second-degree reaction and abides by the Langmuir isotherm. The thermodynamic constants of ΔH°=-4.866 kJ/mol and ΔS°= 21.44 J/mol were determined. As a result of this, the reaction was exothermic, spontaneous, and random, and adsorption was physical adsorption. As a result of the study, sewage sludge ash can be used in the treatment of water containing low concentrations of Mn2+.
AtıfScopus4OpenAlex2İncele - MakaleYalnız künye2022Scopus SJRQ1High-speed treatment of low strength domestic wastewater for irrigation water production in pilot-scale classical, moving bed and fixed bed hybrid MBRs
Tuluk, Banu; Yildiz, Ergun; Nuhoglu, Alper; Tataroglu, Numan Suadi; Gulluce, Ekrem; Cengiz, Ibrahim; Degermenci, Nejdet; Angin, Ilker
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. Established 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) removals. 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.
AtıfScopus16WoS11OpenAlex17İncele - MakaleYalnız künye2022Scopus SJRQ3Comparison of Statistical Methods to Graphical Method in Precipitation Trend Analysis, A Case Study: Coruh Basin, Turkey
Hırca, Tuğçe; Eryılmaz Türkkan, Gökçen
It is a known fact that the precipitation characteristics will become irregular as a result of climate change resulting from global warming. Trend analysis is one of the most effective methods of observing the effects of climate change on precipitation. This study compares the changes in precipitation with traditional trend analysis methods and graphical method (divided into subcategories using the Z-Score Index). Some preliminary analyzes (missing data estimation, homogeneity check, autocorrelation, and removal of the autocorrelation), which are lacking in many studies in the literature, have been performed. In this context, the monthly total precipitation data of the precipitation stations belonging to the Coruh Basin, one of the most important basins of Turkey, for the period 1972–2011 were used. As a result of the study, it was determined that all the stations’ data were homogeneous, and 92% of them were at the Class A level. While 100% trend is determined in Innovative Trend Analysis in total annual precipitation, this rate was just 40% at Mann–Kendall and Spearman's rho at 95% confidence. An increasing trend was determined in the “high” group of total spring precipitation at all stations.
AtıfScopus5WoS4OpenAlex5İncele - MakaleAçık Erişim2022Investigation of the effect of current density and PH on oil and grease removal from leather industry wastewaters by electrocoagulation method
Bi̇Ngül Reçber, Züleyha; Ekmekyapar Torun, Fatma; Kul, Sinan; İRdemez, Şahset
In this study, the effects of pH and current density on the removal of high concentrations of oil and grease in leather industry wastewater by the electrocoagulation method were investigated. Two different types of electrodes were used in the study. Studies with aluminum electrodes have shown that these electrodes are more effective than iron electrodes in removing oil and grease. In addition, aluminum electrodes are affected more by the system pH than iron electrodes. Studies have shown that higher oil and grease removal efficiencies are obtained below pH 4 for both electrodes. While the oil and grease removal efficiency with Al electrodes is 95% at pH 2, this value decreases to 83% at pH 6. In Fe electrodes, while the removal efficiency is 87.83% at pH 2, it decreases to 83% at pH 6. The effect of current density on oil and grease removal was examined and it was observed that the removal efficiency remained constant above a certain current density in aluminum electrodes. While the efficiency of Al electrodes is 83.31% at 0.6 mA cm-2 current density, this value has increased to about 98% at 1.2, 1.8, and 2.4 mA cm-2 current densities. In Fe electrodes, the oil and grease removal efficiency is 82.66% at 0.6 mA cm-2 current density, while it is 90% at 1.2 and 1.8 mA cm-2 current densities and 98% at 2.4 mA cm-2. These results show that the electrocoagulation process removes the oil and grease in wastewater at a high rate. This shows that this process can also be used as pre-treatment before the biological treatment of industrial wastewater with high oil and grease content. Copyright 2021, Yıldız Technical University.
AtıfScopus2WoS2OpenAlex1İncele - MakaleAçık Erişim2021Hydrologic Assessment of Trabzon (NE Turkey) River Basins through the Morphometric Analysis Using Geographic Information System
Yıldırım, Ümit
In this study, morphometric analyses of water catchment basins of 10 different rivers (Ağasar, Fol, Galanima, Değirmendere, Yomra, Yanbolu, Karadere, Küçükdere, Manahoz and Solaklı rivers), which are located in the Eastern Black Sea Region and flows into the Black Sea within the Trabzon city, were done due to investigate the aspect of hydrology. Morphometric parameters related to hydrological processes (drainage density, stream frequency, drainage texture, length of the overland flow, form factor and elongation ratio) were used in the analysis. As the basic parameters for derivation of these parameters; basin area, basin perimeter length, basin length, stream order, stream number and total stream length parameters were used. As a result of the morphometric analysis, it was determined that Değirmendere, Karadere and Solaklı basins are more sensitive to flooding and flashflood, the surface permeability is very low in the Fol and Ağasar basins, and the soil erosion and sediment transport is quite high in the Yanbolu basin.
AtıfOpenAlex5TR Dizin4
İncele - MakaleAçık Erişim2021Investigation of the Roughness Coefficient Effect on Open Channel Flow
Türkkan, Gokçen Eryılmaz
With the effect of global warming in our world, rising sea levels, changing seasons and degrading the ecosystem can cause floods. Preventing floods requires good planning and projecting. The effect of roughness coefficient on open channel flow was investigated with this study. The purpose of the study is to examine the flow in the channel depending on the seasonal change of vegetation cover. This study was carried out on the Sarıhan river, which is located within Bayburt province borders. The flow was simulated using different roughness coefficients. In the study, ArcGIS and Hec-GeoRAS software were used to create a numerical model. HEC-RAS software was preferred to simulate open channel flow. The froude number, velocities in the cross section, the water level and the flow area have been seen to differences with the change of the roughness coefficient. In addition, for four different roughness coefficient values calculated in the study, critical flow rates that will cause flooding in any section of Sarıhan river were determined. In this study, the importance of roughness coefficient, which changes as a result of seasonal changes, was emphasized with this model.
AtıfOpenAlex4TR Dizin3İncele - MakaleAçık Erişim2021Scopus SJRQ4The effect of pH on removal of phosphate from water using aluminum electrodes by electrocoagulation method; [Alüminyum elektrotlar kullanılarak elektrokoagülasyon yöntemi ile sulardan fosfat gideriminde pH'ın etkisi]
İrdemez, Şahset; Bingül, Züleyha; Kul, Sinan; Ekmekyapar Torun, Fatma; Demircioğlu, Nuhi
In this study, the effect of wastewater pH on phosphate removal by electrocoagulation method using aluminum plate electrodes was investigated. For this purpose, experiments were carried out at initial pH values ranging from 3-10, and the effect of the initial pH of the wastewater on phosphate removal efficiency, energy consumption and reaction rate was analyzed. From the results obtained, it was determined that the initial pHs of the optimum wastewater was 3 and 4. Because at low pH, both phosphate removal efficiency is high and the energy consumption of the system is low. While 97% removal efficiency is reached in 20 minutes at pHi=3, it increases in this period with the increase of the wastewater initial pH. These data show that the removal rate is higher at lower initial pHs. While the 1st degree reaction rate constant at pHi=3 is k1=0.2154 min-1, this value decreases to k1=0.071 min-1 at pHi=10. At pHi=3, the energy consumption of the system has been determined as 0.553 kWh m-3 in 12 minutes of contact time. In addition, in the measurements made during the trials, it was observed that the highest PO4-P removal occurred during the period when the pH of the system was between 5-7.
AtıfScopus4OpenAlex1İncele - MakaleAçık Erişim2021Scopus SJRQ1Assessment of Artificial Intelligence Models for Estimating Lengths of Gradually Varied Flow Profiles
Niazkar, Majid; Hajizadeh Mishi, Farshad; Eryilmaz Türkkan, Gökçen
The study of water surface profiles is beneficial to various applications in water resources management. In this study, two artificial intelligence (AI) models named the artificial neural network (ANN) and genetic programming (GP) were employed to estimate the length of six steady GVF profiles for the first time. The AI models were trained using a database consisting of 5154 dimensionless cases. A comparison was carried out to assess the performances of the AI techniques for estimating lengths of 330 GVF profiles in both mild and steep slopes in trapezoidal channels. The corresponding GVF lengths were also calculated by 1-step, 3-step, and 5-step direct step methods for comparison purposes. Based on six metrics used for the comparative analysis, GP and the ANN improve five out of six metrics computed by the 1-step direct step method for both mild and steep slopes. Moreover, GP enhanced GVF lengths estimated by the 3-step direct step method based on three out of six accuracy indices when the channel slope is higher and lower than the critical slope. Additionally, the performances of the AI techniques were also investigated depending on comparing the water depth of each case and the corresponding normal and critical grade lines. Furthermore, the results show that the more the number of subreaches considered in the direct method, the better the results will be achieved with the compensation of much more computational efforts. The achieved improvements can be used in further studies to improve modeling water surface profiles in channel networks and hydraulic structure designs.
AtıfScopus11WoS7OpenAlex12İncele - MakaleAçık Erişim2021Scopus SJRQ3A novel weighted mean-squared error optimization model to obtain optimal conditions of adsorption factors for a lead removal process
Özdemir, Akın; Teke, Çağatay; Serencam, Hüseyin; Uçurum, Metin; Gündoğdu, Ali
Lead (Pb) removal process from wastewater is an important issue to prevent health problems for people. For this particular purpose, a low-cost adsorbent may be beneficial for improving the adsorption capacity for the Pb removal process. The aims of this paper are four-fold. First of all, a D-optimal experimental design was selected to reduce experimental runs and its cost. Second, the effect of four adsorption design factors, stirring speed (rpm), adsorbent dosage (g), pH level, and initial metal concentration (ppm), was examined. Also, the yellow natural stone, which is from Bayburt, Turkey, was used as a cheap adsorbent for the Pb removal process from the solu-tion. Third, a novel weighted mean-squared error optimization model was developed to obtain optimal adsorption levels for adsorption factors. Besides, a verification study was conducted to verify the results of the adsorption experiment. Finally, the lead (Pb(II)) removal capacity of the yellow Bayburt stone was obtained to be 46.031 mg/g, and the results of the experiment from the proposed methodology showed a good performance for the removal study.
- MakaleAçık Erişim2021Scopus SJRQ1Modelling of the discharge response to climate change under RCP8.5 scenario in the Alata river basin (Mersin, SE Turkey)
Yıldırım, Ümit; Güler, Cüneyt; Önol, Barış; Rode, Michael; Jomaa, Seifeddine
This study investigates the impacts of climate change on the hydrological response of a Mediterranean mesoscale catchment using a hydrological model. The effect of climate change on the discharge of the Alata River Basin in Mersin province (Turkey) was assessed under the worstcase climate change scenario (i.e., RCP8.5), using the semi-distributed, process-based hydrological model Hydrological Predictions for the Environment (HYPE). First, the model was evaluated temporally and spatially and has been shown to reproduce the measured discharge consistently. Second, the discharge was predicted under climate projections in three distinct future periods (i.e., 2021–2040, 2046–2065 and 2081–2100, reflecting the beginning, middle and end of the century, respectively). Climate change projections showed that the annual mean temperature in the Alata River Basin rises for the beginning, middle and end of the century, with about 1.35, 2.13 and 4.11 °C, respectively. Besides, the highest discharge timing seems to occur one month earlier (February instead of March) compared to the baseline period (2000–2011) in the beginning and middle of the century. The results show a decrease in precipitation and an increase in temperature in all future projections, resulting in more snowmelt and higher discharge generation in the beginning and middle of the century scenarios. However, at the end of the century, the discharge significantly decreased due to increased evapotranspiration and reduced snow depth in the upstream area. The findings of this study can help develop efficient climate change adaptation options in the Levant’s coastal areas.
AtıfScopus16OpenAlex19İncele - MakaleYalnız künye2021Comparison of kinetics of Cr (III) ions removal from wastewater using raw and activated montmorillonite minerals
İrdemez, Şahset; Durmuş, Gül; Kul, Sinan; Torun, Fatma Ekmekyapar; Bingül, Züleyha
In this study, kinetics of the removal of Cr (III) from the waters by adsorption have been investigated using montmorillonite natural clay that was obtained from the vicinity of Narman, Erzurum in Turkey. Activation energy, thermodynamic values and adsorption kinetics were determined. In addition, the trials were repeated by subjecting to the same adsorbent activation process. The values found for these two adsorbents were compared. As a result of the experiments, the parameters affecting the adsorption kinetics were examined. It was determined that the adsorption process could be best depicted by pseudo second order reaction kinetics. Using pseudo second order reaction rate constants, ΔH° =-25.791 kJ mol-1 and ΔS° = 106.19 joule mol-1 were calculated for raw adsorbent. For the activated adsorbent, ΔH° =-18,806 kJ mol-1 and ΔS° = 79.37 joule mol-1 were calculated. That ΔG° increases as temperature increases indicates; adsorption is more spontaneous at high temperatures. Negative ΔH° values show that the reaction is exothermic. The positive values of ΔS° indicate increased randomness at the adsorbent/solution interface during the adsorption of chrome.
AtıfScopus2WoS1OpenAlex3İncele
