İnşaat Mühendisliği Bölümü Koleksiyonu

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Effect of waste steel fiber use on concrete behavior at high temperature
(Elsevier Ltd, 2024) Doğruyol, Murat; Ayhan, Ersin; Karaşin, Abdulhalim
Recently, recycling of waste vehicle tyres which pose a significant risk to environmental health has become an important research issue due to environmental concerns worldwide. To handle the waste tyre pollution problem, recycling waste into new products and using waste to improve other materials’ properties can be considered. Waste vehicle tyres can be used in the production of energy and various materials, providing economic and environmental advantages. In this study, experimental studies were carried out on the use of waste tyre steel fiber (WS) obtained from the recycling of heavy vehicle tyres in concrete, including the goal of recycling and reducing the need for raw materials. In one experimental group, waste tyre steel was added to concrete at 0.4% by volume instead of fine aggregate, while in the other experimental group it was added at 0.8% by volume. In the study, in addition to mechanical analyses, many microanalysis experiments were carried out to understand whether there was a strong relationship between the results. The study was conducted at target temperatures of 400, 600 and 800 °C depending on the fire scenario for building and construction materials according to ISO 834 and ASTM E119 standards. Compressive strength losses and characterization changes in 15 cm cube plain concrete and composite concrete specimens exposed to targeted high temperatures for 60 minutes were compared in terms of strength. Ultrasonic pulse velocity (UPV), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), differential thermal analysis (DTA), X-ray diffraction analysis (XRD) and Fourier transform infrared spectroscopy (FTIR) analysis was also performed, as it was understood that there was not enough data in the literature regarding waste tyre steel fiber reinforced concrete. General results showed that fiber-added concrete made significant contributions to concrete performance at high temperatures. © 2024 The Authors
Finite element modeling of a torque rod forging process
(Springer International Publishing Ag, 2014) Keskin, M. S.; Bingöl, S.; Elem, H. B.; Atar, A.
Aluminum forging products has been increasingly used in automotive and aerospace industry due to their lightness and strength. Torque Rod is a connection part used for tying of the axle to the chassis frame. In this study, torque rod part from two different aluminum alloys (AA7075 and AA6061) were analyzed by finite element method. Three different initial temperatures of the workpiece; 300, 400 and 500 degrees C, have been used in simulations. Finally, the load-stroke and effective stress-stroke diagrams were examined according to forging of the mentioned aluminum alloys at different temperatures.
Metaheuristic optimization in structural engineering
(Springer International Publishing Ag, 2016) Değertekin, S. Ö.; Geem, Zong Woo
Metaheuristic search methods have been extensively used for optimization of the structures over the past two decades. Genetic algorithms (GA), ant colony optimization (ACO), particle swarm optimization (PSO), harmony search (HS), big bang-big crunch (BB-BC), artificial bee colony algorithm (ABC) and teaching-learning-based optimization (TLBO) are the most popular metaheuristic optimization methods. The basic principle of these methods is that they make an analogy between the natural phenomena and the optimization problems. In this chapter, recently developed metaheuristic optimization methods such as self-adaptive harmony search and teaching-learning-based optimization are reviewed and the performance of these methods in the field of structural engineering are compared with each other and the other metaheuristic methods.
Quantitative evaluation of the damage to RC buildings caused by the 2023 southeast Turkey earthquake sequence
(SAGE Publications Inc., 2024) Pujol, Santiago; Bedirhanoğlu, İdris; Dönmez, Cemalettin; Dowgala, Jeffrey D.; Yıldırım, Meltem Eryılmaz; Klaboe, Kari; Köroğlu, Fahri Baran
Data from 15 earthquakes that occurred in 12 different countries are presented showing that, without better drift control, structures built with building codes allowing large seismic drifts are likely to keep leaving a wide wake of damage ranging from cracked partitions to building overturning. Following the earthquake sequence affecting southeast Turkey in 2023, a team led by Committee 133 of the American Concrete Institute surveyed nearly 250 reinforced concrete buildings in the area extending from Antakya to Malatya. Buildings ranging from 2 to 16 stories were surveyed to assess their damage and evaluate the robustness of their structures in relation to overall stiffness, as measured by the relative cross-sectional areas of structural walls and columns. The majority of the buildings were estimated to have been built in the past 10 years. Yet, the structures surveyed were observed to have amounts of structural walls and columns comparable with amounts reported after the Erzincan (1992), Duzce (1999), and Bingol (2003) Earthquakes in Turkey. These amounts are, on average, much smaller than the wall and column amounts used in Chile and Japan. Because of that lack of robustness and given the intensities of the motions reported from Antakya to Malatya (with 10 stations with peak ground velocity (PGV) of 100 cm/s or more), it is concluded that structures in this region experienced large drifts. Excessive drift (1) exposed a myriad of construction and detailing problems leading to severe structural damage and collapse, (2) induced overturning caused by p-delta for some buildings, and (3) caused widespread damage to brittle masonry partitions. The main lesson is simple: ductility is necessary but not sufficient. It is urgent that seismic drift limits are tightened in high-seismicity regions worldwide.
Estimating IDF curves under changing climate conditions for different climate regions
(IWA Publishing, 2023) Gül, Burak; Kayaalp, Necati
Although climate models can highlight potential shifts in intensity–duration–frequency (IDF) curves, their limited geographical and temporal resolutions limit their direct use in predicting sub-daily heavy precipitation. To use global or regional model outputs to predict urban short-term precipitation, approaches that give the requisite level of spatial and temporal downscaling are required, and these processes remain one of the difficulties that have demanded intensive effort in recent years. Although no novel methods are given in this work, there are few studies in the literature that investigate the impact of climate change on the analysis and design of infrastructure-related engineering structures. Therefore, the purpose of this research is to determine the potential changes in IDF curves because of climate change. The equi-distance quantile matching method was used to turn future rainfall forecast data from global climate models (HadGEM2-ES, MPI-ESM-MR, and GFDL-ESM2M) corresponding to RCP4.5 and RCP8.5 scenarios into standard duration rainfall data, and new IDF curves were generated. These IDF curves corresponded very well with those generated from observed data (R2 ≈ 1). The HadGEM2-ES model predicts up to a 25% rise in rainfall intensity, whereas the other two models expect up to a 50% drop.
Modelling of hydrogenotrophic denitrification process in a venturi-integrated membrane bioreactor
(Taylor and Francis Ltd., 2022) Gül, Ertuğrul; Kayaalp, Necati
The aim of this study is to model a hydrogenotrophic denitrification process in a venturi-integrated submerged membrane bioreactor (MBR) system. The MBR was operated in batch mode using feed concentrations of 100 and 150 mg NO3-N/L. In contrast to most of the denitrification process models that represent the mixed culture with one composite biomass parameter, the biomass was subdivided into two main categories in this modelling study: mainly nitrate-reducing biomass and mainly nitrite-reducing biomass. The determination coefficients (r 2) in the range of 0.97–0.99 indicate that the model successfully simulates the concentrations of nitrate- and nitrite-nitrogen in the bioreactor. The maximum specific growth rate of nitrite-reducing biomass (0.06 h−1) was found to be higher than that of nitrate-reducing biomass (0.0002 h−1). Similarly, the growth yield coefficient of nitrite-reducing biomass was higher than that of nitrate-reducing biomass (0.44 vs. 0.31 g biomass/g substrate). The kinetic and stoichiometric coefficients obtained from this modelling study suggest that the limiting step determining the overall conversion rate of hydrogenotrophic denitrification process is the conversion of nitrite to nitrogen gas.
Stability of MSW landfill slopes reinforced with geogrids
(MDPI, 2022) Keskin, Mehmet Salih; Kezer, Sedat
Slope stability is one of the main problems encountered in MSW (municipality solid waste) landfill designs. Slope stability calculations become difficult due to the heterogeneous structure of MSW landfills and leachate, and therefore, slope geometries are formed by choosing low slope angles for safe designs. This causes less waste to be stored on site. This study presents slope stability analyses of MSW landfills. Numerical analyses were performed using finite element and limit equilibrium methods. The stability behavior of landfill slopes was analyzed for both unreinforced and geogrid-reinforced conditions in order to investigate the effects of shear strength parameters, the unit weight of soil waste, and material model parameters. It has been seen that the stability of landfill slopes can be increased significantly using geogrid materials. When the optimum geogrid parameters obtained from the numerical analysis results are used, it has been observed that the safety factor of the slope can be increased by up to approximately two times. Slopes in landfills reinforced with geogrid reinforcements can be formed steeper, allowing more solid waste to be stored. Considering the high initial investment cost of MSW landfills, it has been concluded that storing more solid waste with the use of geogrids will provide significant economic gains. Based on the results, the optimum values of geogrid parameters were determined and suggested for maximum reinforcing effects in MSW landfill slopes.
Effect of seismic isolation on the performance of high-rise buildings with torsional instability
(MDPI, 2023) Sarıtaş, Fevzi; Bedirhanoğlu, İdris; Konak, Arova; Keskin, Mehmet Salih
Seismic bearings have been used to mitigate the harmful effect of the earthquakes. Torsion mode, one of the most important irregularities, generally increases the shear forces to the vertical members such as columns and shear walls in turn this may results in brittle failure of the reinforced concrete (RC) members. Accordingly, it is vital to eliminate the torsion failure mode or switch to the higher modes with lower mass contribution. This study has evaluated the seismic performance of a high-rise building with torsion mode through push-over analysis including nonlinear time history analyses. The damage conditions of RC structural members are defined considering the Eurocode definitions and general performance assessments of the building have been evaluated accordingly. Lead rubber bearings have been used for base isolation system. By using enough number of rubber bearings, the dominant torsion mode (first free vibration mode) has been shifted to higher modes. Various earthquake records have been used in non-linear dynamic analysis to evaluate the positive effects of the bearings. The results revealed that proper arrangement of rubber bearings in structural plan of ground floor can effectively improve dynamic behavior of a high rise building with torsional instability to achieve better seismic performance.
The effect of voids on flexural capacity of reinforced concrete slabs
(Budapest University of Technology and Economics, 2023) Kıpçak, Fırat; Erdil, Barış; Tapan, Mucip; Karaşin, Abdulhalim
The voided reinforced concrete slab system is mainly produced with polyester foam placed mostly at the bottom of the slab. The aim of the voids is to reduce the weight of the slab. In this paper behavior of the voided reinforced concrete slabs in which voids placed at the mid-height of the slab cross-section, is examined analytically. A series of models were created to come up with a lightweight slab. Two distinct slab models were analyzed using the ABAQUS software. In the first group, slabs had three layers, in which bottom and top layers were of solid reinforced concrete, but the mid layer was of voided unreinforced concrete. In the second layer, in order to increase the contact between top and bottom layers of the slab, crossties were utilized, and the mid layer was reinforced accordingly. Since all the layers were 5 cm thick, the total thickness of the slabs were 15 cm. Slabs were 100 cm wide and 200 cm long. They were simulated the three-point bending test. Concrete damaged plasticity material model (CDPM) for concrete and elastoplastic material model for steel was selected. From the results it was found that moment capacity decreased with the increase in the volume of the voids. There was a sudden decrease in strength after reaching the yield strength in voided slab without a crosstie. In addition, crossties enabled the reduction of the weight of the slabs without significant decrease in moment capacity.
Optimized seismic design of planar and spatial steel frames using the hybrid learning based jaya algorithm
(Elsevier Ltd., 2022) Değertekin, Sadık Özgür; Tutar, Hikmet
In this paper, three powerful metaheuristic algorithms, modified teaching learning based optimization, modified jaya algorithm and hybrid learning based jaya algorithm are presented for optimized seismic design of planar/spatial steel frames. The hybrid learning based jaya algorithm combines the learning phase of teaching learning based optimization and jaya algorithm. The goal is to design steel frames of minimum weight under strength, interstory drift and geometric-size constraints. One planar and two spatial steel frames previously designed for minimum weight by different metaheuristic optimization methods are taken as design examples to test the proposed methods. The methods presented in this paper are compared with other referenced algorithms in terms of optimized weight and computational cost. It is found that the hybrid learning based jaya algorithm outperforms modified teaching learning based optimization, modified jaya algorithm and its other competitors in all test problems.
Küresel iklim model verilerinin farklı yöntemlerle ayrıştırılması ve geleceğe yönelik yağış tahminlerinin yapılması
(Niğde Ömer Halisdemir Üniversitesi, 2023) Gül, Burak
Küresel iklim değişikliği, her geçen gün Dünya genelinde daha fazla etkisini artırarak tehlikeli sonuçlara neden olmaktadır. Özellikle iklim değişikliği kaynaklı şiddetli yağışlar, sel felaketlerine yol açmaktadır. Bu sel olayları, can kaybına ve maddi hasara neden olabilmektedir. Bu nedenle, çeşitli önleyici çalışmalar yürütülmektedir. Bu çalışmalardan biri, Yağış Şiddeti-Süre-Frekans (IDF) eğrilerinin oluşturulmasıdır. Ancak bu eğriler genellikle geçmiş tarihsel verilere dayandığından, gelecek için kullanılmaları uygun görülmemektedir. Bu nedenle, bu çalışmada iklim modeli verileri ve ayrıştırılmış yağış verileri kullanılarak iklim değişikliğini de içeren geleceğe yönelik yeni IDF eğrileri elde etmek için farklı yöntemler kullanılmıştır.
GEP prediction of scour around a side weir in curved channel
(Taylor and Francis Ltd., 2014) Önen, Fevzi
Side-weirs have been widely used in hydraulic and environmental engineering applications. Side-weir is known as a lateral intake structure, which are significant parts of the distribution channel in irrigation, land drainage, and urban sewerage system, by flow diversion device. Local scour involves the removal of material around piers, abutments, side-weir, spurs, and embankments. Clearwater scour depth based on five dimensional parameters: approach flow velocity (V1/Vc), water head ratio (h1-p)/h1, side-weir length (L/r), side-weir crest height (b/p) and angle of bend θ. The aim of this study is to develop a new formulation for prediction of clear-water scour of side-weir intersection along curved channel using Gene Expression Programming (GEP) which is an algorithm based on genetic algorithms (GA) and genetic programming (GP). In addition, the explicit formulations of the developed GEP models are presented. Also equations are obtained using multiple linear regressions (MLR) and multiple nonlinear regressions (MNRL). The performance of GEP is found more influential than multiple linear regression equation for predicting the clearwater scour depth at side-weir intersection along curved channel. Multiple nonlinear regression equation was quite close to GEP, which serve much simpler model with explicit formulation.
Long-term meteorological and hydrological drought characteristics on the lower Tigris-Euphrates basin, Türkiye: relation, impact and trend
(Springer Science and Business Media Deutschland GmbH, 2023) Eşit, Musa; Çelik, Recep; Akbaş, Ergün
This study aims to provide a comprehensive analysis of meteorological and hydrological droughts in the lower Tigris-Euphrates basin, Türkiye over 12-month time scale using the standardized precipitation index (SPI) and the Standardized Precipitation Evapotranspiration Index (SPEI) and the standardized streamflow index (SDI). To evaluate monthly trends of the SPI, SPEI, and SDI series, Mann–Kendall (MK), Spearman Rho (SR), and innovative trend analysis (ITA) tests are employed. The intrinsic relationships between the hydrological and meteorological drought in the study area as well as the specifics of how the oscillation period changes over time can also be obtained via wavelet transform coherence (WTC), which can reveal essential information. The results of all trend tests performed a decreasing trend consistently at stations 17275, 17810, 17948, 17950, and 17968 for all months in terms of SPI. SPEI is more sensitive to trend detection than SPI when taking into account all trend testing. In addition, the three trend tests are found to be more consistent with each other when SPEI is compared to SPI. According to SDI, the ITA method is clearly superior to the other two methods for identifying hidden trends. The ITA method, for example, captures a considerably increasing/decreasing trend at stations E26A038 (January and February), E26A012 (January, February, and from May to December), and E26A033 (from June to December) despite MK and SR tests finding no significant trends at any of the stations. When considering the WTC, positive month signals are strongly correlated with 12-month periods, according to the majority of stations.
Integrated gis-based multi-criteria analysis for groundwater potential mapping in the euphrates’s sub-basin, Harran Basin, Turkey
(2021) Aslan, Veysel; Çelik, Recep
The Harran Basin is an important region where agricultural activities have been conducted for millennia. The agricultural water needs of the basin are largely met with surface irrigation through the GAP (South-Eastern Anatolian Project), while groundwater is used in some regions as potable water, tap water, and irrigation water. In this study, the groundwater potential of the Harran Basin was determined through the “GIS-based Multi-Criteria Decision Making (MCDM)” Method. Ten criteria were considered: Land Use, Soil, Geomorphology, Geology, Aquifer, Drainage Density, Rainfall, Slope, Lineament Density, and Terrain Class. The weights of these criteria were determined through the AHP method, and the operations were performed in the ArcGIS environment. As the results of this study, the Groundwater Potential Index (GWPI) values were obtained, and five regions were determined based on their Groundwater Potential Zone (GWPZ) classifications: very poor GWPI: 0.10% (5.14 km2); poor GWPI: 29.20%; moderate GWPI: 38.20%; good GWPI: 30.90%; and very good GWPI: 1.50%). We determined that the region is a plain with a low slope and geologically consists of limestone. Notably, areas with poor water potential are mountainous and hilly, and the slopes over these areas are high.
Experimental investigation of usability of treatment sud ash with road filling materials in highways
(MDPI, 2023) Akyıldız, Mehmet Hayrullah; Yön, Seda
Increasing environmental pollution due to the rapid increase in the world population is one of the most important problems of humanity, perhaps even the first. Environmental elements that are vital for living things air, soil and water are becoming more polluted and unusable day by day. For this reason, various improvement studies are carried out in these areas. One of them is wastewater treatment plants built to control water pollution. While the water treated in the sedimentation ponds in these facilities is recycled into nature, it leaves waste treatment sludge behind. These waste sludges collected in a certain place are destroyed by various methods such as composting, drying or incineration. In previous studies, the usability of sewage sludge ash in soil improvement was investigated. In this study, the usability of sewage sludge ash as road filling material was investigated (Ash was added to the clay soil in determined percentages. These percentages are respectively; 0%, 2.5%, 5%, 7.5%, 10%, 12.5% and 15%). Treatment sludge ash was obtained from Bursa Fluidized Bed Sludge Incineration and Energy Recovery Facility. Then, the samples prepared by adding treatment sludge ash to the clay soil at certain rates were subjected to the CBR test with the Standard Proctor test. The values obtained as a result of the experiments were compared with the values given in the Highways Technical Specifications and it was determined whether they were suitable as a road filling material. The engineering properties of the soil used indicate that the soil is weak (clay soil). The treatment sludge ash added as an additive has improved all the properties of the soil to a certain extent.
Evaluation with stream characteristics of downstream flood problems after dam construction
(Taylor and Francis, 2014) Bağatur, Tamer; Hamidi, Nizamettin
The flood may cause serious loss of life and property. The evaluation of flood events is necessary for the planning and design of engineering projects. In a dam, flood problems should be considered for both upstream and downstream conditions. The characteristics of flood problems can be derived from observation of dam sites. This paper aims to evaluate the impact of flood hazards from spillway based on downstream conditions after dam construction. Also, the paper discusses downstream flood problems depending on stream characteristics in an example dam site. In results, three reasons are determined for downstream floods problems: control problems of spillway gates, the naturally developing vegetation through channel flow line and incompetence of stream cross-section for carrying of flood flows. Therefore, downstream conditions should be investigated before dam construction. This investigation can be considered in the planning phase. In addition, the cross-section and longitudinal profile of stream should be controlled via maintenance of stream after dam construction. In stream cross-section problems (such as vegetation, incompetence and irregularities), some modifications (e.g. straighten, deepen, and widen) can be applied with engineering works.
The mutual interaction between the structural footprint and number of floors in steel structures
(Mim Research Group, 2021) Işık, Ercan; Karaşin, İbrahim Baran
Structural dimensions and number of floors are some of the factors affecting the building behaviour under the earthquake effects. In this study, the structural footprint and the number of floors were selected as a variable. For this purpose, a steel structure model with fixed dimensions and properties of load-bearing system elements was selected. The structural footprint was selected as the first variable and then five different structure models were created. The structural footprint was changed by setting each axial clearance in both directions. Each axial clearance was increased by 0.5m in each structure model. Three different number of floors as to be 5, 6 and 7 floors were selected as the second variable. Eigenvalue and pushover analyses were performed for each model and each number of floors. As a result of the analyses, the target displacement values for period, frequency, cumulative participation mass ratio, base shear force, settlement, stiffness and degree of damage were acquired separately. As the structural footprint and number of the floors increase, while the period, settlement and the target displacement values increased, on the contrary, there was a decrease in participation mass ratio, base shear forces and stiffness values. In the study, cost comparisons of building construction were also made considering the change in the total structural area and the number of floors. The criterion of safety and economy was ignored due to increase both in the number of floors and the footprint. This study emphasizes the importance of avoiding the unnecessary structural dimensions via optimum design principles. As structural footprint area and number of floors increase, period values increase, stiffness and seismic capacity values decrease. As the number of floors and footprint area increases, the total building area increases, so the approximate building cost has also increased.
Betonarme yapılarda kullanılan malzeme modellerinin karşılaştırılması
(Bitlis Eren Üniversitesi, 2019) Işık, Ercan; Özdemir, Mesut; Karaşin, İbrahim Baran; Karaşin, Abdulhalim
Malzeme modelleri yapıların sismik analizlerinde önemli rol oynamaktadır. Literatürde, betonarme yapılarda kullanılan malzemelerin gerilme-şekil değiştirme ilişkisini tanımlamak için çeşitli malzeme modelleri bulunmaktadır. Beton ve çelik gibi iki farklı yapı malzemesinin bir arada kullanılması ile elde edilen betonarme yapılarda malzeme modelleri ayrı bir öneme sahiptir. Hem beton hem de çelik için kullanılan farklı malzeme modellerinin karşılıklı etkileşimi çalışmanın konusunu oluşturmaktadır. Çalışmanın amacı betonarme yapılarda kullanılan farklı malzeme modellerinin birbirleri ile uyumlu olup olmadığını kontrol etmektir. Bu çalışmada dörder farklı beton ve çelik malzeme modeli dikkate alınarak seçilen iki katlı betonarme bir yapı için hesaplamalar yapılmıştır. Her bir malzeme modeli için X ve Y doğrultularında taban kesme kuvveti – deplasman eğrileri elde edilmiştir. Çalışmada dikkate alınan malzeme modelleri hakkında bilgiler verilmiştir. Farklı malzeme modelleri arasında bir uyum olduğu gözlemlenmiştir. Bu malzeme modellerinin birlikte kullanılabilirliğini ortaya koymuştur.
Centrifuge model tests and numerical analysis of uplift capacity of strip anchors in geogrid-reinforced sand
(MDPI, 2023) Bildik, Selçuk; Dickin, Edward Alan; Keskin, Mehmet Salih; Ilamparuthi, Kanniappan; Laman, Mustafa
Anchor-type foundations are one of the foundation types used in structures subject to tensile forces. These anchors are generally designed according to the weight of the soil on them depending on the depth they are buried at and the frictional resistance obtained from the failure surfaces during failure. One method of increasing the uplift capacity of the foundation without increasing the burial depth is the use of geogrid material. In this study, the uplift capacities of strip anchor plates at different embedment depths were investigated by considering the geogrid effect placed in different combinations. The aim of the study is to investigate whether a more economical solution can be obtained by using geogrid without increasing the embedment depth of the anchor plate. Experiments were carried out using centrifugal experimental setup, which gives values closer to the real results. The tests were performed on sand of two different densities for anchor burial depths H/B = 2 and H/B = 5. According to the results, the uplift capacity is significantly improved when geogrid is used. As the reinforcement configuration, the use of a single geogrid layer placed just above the anchor plate with an inclination angle of 45 degrees gave more effective results than using the geogrid horizontally and vertically. In the study, up to 98% increases in uplift capacity were obtained with reinforcement. In addition, the prototype model was analyzed with a numerical program based on the finite element method, and the results were compared with the experimental results. As a result of the comparison, it was observed that the experimental and numerical results were compatible with each other. Suggestions for practice are presented using the results obtained.
Anoxic treatment of agricultural drainage water in a venturi-integrated membrane bioreactor
(Multidisciplinary Digital Publishing Institute (MDPI), 2023) Kayaalp, Necati
Due to low sludge production and being a clean source without residuals, hydrogen-based autotrophic denitrification appears to be a promising choice for nitrate removal from agricultural drainage waters or water/wastewater with a similar composition. Although the incorporation of hydrogen-based autotrophic denitrification with membrane bioreactors (MBRs) enabled almost 100% utilization of hydrogen, the technology still needs to be improved to better utilize its advantages. This study investigated the anoxic treatment of both synthetic and real drainage waters using hydrogen gas in a recently developed membrane bioreactor configuration, a venturi-integrated submerged membrane bioreactor, for the first time. The study examined the effects of the inflow nitrate concentration, and the use of a venturi device on the removal efficiency, as well as the effects of the presence of headspace gas circulation and circulation rate on membrane fouling. The study found that using the headspace gas circulation through a venturi device did not significantly affect the treatment efficiency, and in both cases, a removal efficiency of over 90% was achieved. When the inlet NO− 3 –N concentration was increased from 50 mg/L to 100 mg/L, the maximum removal efficiency decreased from 98% to 92%. It was observed that the most significant effect of the headspace gas circulation was on the membrane fouling. When the headspace gas was not circulated, the average membrane chemical washing period was 5 days. However, with headspace gas circulation, the membrane washing period increased to an average of 12 days. The study found that the headspace gas circulation method significantly affected membrane fouling. When the upper phase was circulated with a peristaltic pump instead of a venturi device, the membrane washing period decreased to one day. The study calculated the maximum hydrogen utilization efficiency to be approximately 96%.

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