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Öğe Anaerobic/aerobic cycle effect on di(2-ethylhexyl) phthalate and pentachlorophenol removal from real textile wastewater in sequencing batch biofilm reactor(Elsevier Sci Ltd, 2020) Yakamercan, Elif; Aygün, AhmetThis study aims to investigate the treatability of pentachlorophenol encountered in cotton textile plants and di(2-ethylhexyl) phthalate used in synthetic textile production. They were selected as model micropollutants. Experiments were carried out at different anaerobic/aerobic (A/O) sequences (4 h/16 h, 8 h/12 h, 12 h/8 h, 16 h/4 h) at constant hydraulic retention time (36 h) and solid retention time (15 d) to determine the effect of biocarriers addition and anaerobic/aerobic cycle time on micropollutant removal from real textile wastewater. During the study period, sequencing batch reactor and sequencing batch biofilm reactor, which contains K3 Kaldnes bio-carrier with 50% filling ratio, were fed with a real textile wastewater. Reactors were operated with a total cycle period of 24 h (fill: 0.5 h; react: 20 h; settle: 2 h; decant: 1 h; idle: 0.5 h). Their performances were compared in terms of PCP, DEHP and macro pollutants (BOD5, COD, TOC, TN, TP, and color) removals. The average DEHP and PCP concentrations in feed wastewater were 124.5 +/- 5.24 and 12.8 +/- 0.27 mg/L, respectively. The maximum DEHP removal efficiencies were 72.2% for SBBR at 4 h/16 h (A/O) and 42.1% for SBR at 8 h/12 h (A/O) sequence. The PCP removal efficiency was not affected significantly by the change of aeration times and remained 51.1% -56.5% for SBBR and 35.0%-43.2% for SBR. The addition of biocarrier caused 30.0% and 13.0% increase in removal efficiency for DEHP and PCP, respectively. (C) 2020 Elsevier Ltd. All rights reserved.Öğe Application of sequencing batch biofilm reactor (SBBR) in dairy wastewater treatment(Korean Institute Chemical Engineers, 2019) Ozturk, Arzu; Aygün, Ahmet; Nas, BilgehanApplication of lab-scale sequencing batch (SBR) and sequencing batch biofilm reactors (SBBR) for treatment of dairy wastewater was investigated under organic loading of 1,130-1,560 gBOD(5)/m(3)d. The main characteristics of the dairy wastewater were: pH=4.9, chemical oxygen demand (COD)=16,264 mg/l; biological oxygen demand (BOD5)=10,536 mg/l, PO4-P=342 mg/l; total nitrogen (TN)=224 mg/l. SBBR was filled with the Kaldnes K1 biocarrier at 30% of the volume of empty reactor. The SBR and SBBR were operated in fixed 24 h cycles, each consisting of 30 min fill up, 22 h aeration, 1.5 h settle, 30 min decant, and idle with a hydraulic retention time (HRT) of 8 days. Operational parameters such as pH, dissolved oxygen (DO), mixed liquor suspended solid (MLSS), solids retention time (SRT) and sludge volume index (SVI) were monitored during the whole cycle. The effects of these parameters on the COD, nitrogen and phosphorus removal were discussed in this paper. As a result, adding biocarrier to the reactor had a positive effect on organic with COD removal of 63.5% for SBR and 81.8% for SBBR and nutrient removal with ammonium removal of 66.0% for SBR and 85.1% for SBBR in treatment of dairy wastewater.Öğe ATIKSU ARITMA TESİSLERİNDE MİKRO PLASTİKLER VE GİDERİM YÖNTEMLERİ(Bursa Uludağ Üniversitesi, 2020) Bozdaş, Kübra; Üstün, Gökhan Ekrem; Aygün, AhmetAtıksu arıtma tesislerine her gün farklı kaynaklardan mikro plastikler gelmektedir ve mikro plastikleri gidermek için tasarlanmamışlardır. Buna rağmen birincil ve ikincil arıtma süreçlerinde mikro plastiklerin giderimi mevcuttur. Yapılan çalışmalar atıksu arıtma tesislerinin tatlı su ortamları için potansiyel bir mikro plastik kirliliği kaynağı olduğunu kanıtlamıştır. Yüksek oranlarda giderim verimi olmasına rağmen büyük hacimlerde deşarj göz önüne alındığında alıcı ortamlar için mikro plastik kirlilik söz konusudur. Ayrıca arıtma çamurunun gübre olarak yeniden kullanımı sonucunda çamurda tutulan MP'ler toprak kirliliğine neden olmaktadır. Mikro plastiklerin etkili bir şekilde giderimi üçüncül arıtmada uygulanan ileri arıtma teknolojilerine göre değişmektedir. Daha önce yapılan çalışmalar incelendiğinde mikro plastiklerin gideriminde en yüksek verimin Membran Biyoreaktörler ile olduğu görülmektedir. Arıtma tesisleri tasarımında mikro plastiklerinin uygun bir şekilde giderimini sağlayan ileri arıtma teknolojilerinin seçilmesi mikro plastik kirliliğinin azalmasında etkili bir yöntem olabilir.Öğe Comparison of Disperse Blue 79 Dye and Reactive Yellow 160 Dye Removal Efficiency by Electrocoagulation Method(Yakup Yakut, 2018) Keyikoğlu, Ramazan; Can, Orhan Taner; Aygün, Ahmet; İşleyen, MehmetThe textile industry uses high amount of water and generates wastewater that requires effective wastewater treatment technologies. Textile industry in Turkey is an advanced industry particularly in Bursa. During the dying process of fabrics and the fibres a lot of water, synthetic dyes and various chemicals are used, and consequently wastewater is produced that contains complex pollutants with different chemical structure. In particular, dyes that have high water solubility and low fixation rates hydrolyse before they are fully fixed, which results in high amount of waste dye. Decreased light permeability due to the colour caused by the waste dye prevents photosynthetic activities and oxygen depletion occurs. Furthermore, the presence of toxic and mutagenic dyes in water bodies adversely affect aquatic life. Releasing them into the sewage system without treatment can cause problems in biological processes of urban wastewater treatment plants. Therefore, there is a need for innovative, cost effective and efficient wastewater treatment technologies for the treatment of wastewater containing dyes before they are released to the water systems. Electrocoagulation is known to be an effective method especially in colour removal from textile industry wastewaters. In this study, as an effective method for colour removal from waters electrocoagulation was applied to a disperse dye (Disperse Blue 79), which is in a colloid form in a dye solution, and to a reactive dye (Reactive Yellow 160), which has an anionic character and is dissolved in water. After a 10 minutes experiment period with 0.1 A current intensity %92.45 color removal rate was obtained for Disperse Blue 79 whereas for the Reactive yellow 160 color removal rate was only %54.84. Study results shows the importance of dye type in color removal with electrocoagulation method.Öğe Comparison of the effects of various supporting electrolytes on the treatment of a dye solution by electrocoagulation process(Elsevier, 2019) Keyikoğlu, Ramazan; Can, Orhan Taner; Aygün, Ahmet; Tek, AhuLaboratory experiments were conducted to investigate the effect of some supporting electrolytes on the treatment of Reactive Black 5 (RB5) by electrocoagulation using aluminum and iron electrode couples. Electrolytes, which contain Cl-, SO42-, NO- anions and Na+, K+, NH4+ cations, were compared in terms of color removal efficiencies. The presence of SO42- led to poor performances with aluminum electrodes yielding a removal efficiency close to 45% at 8.33 A/m(2). Similarly, the presence of NO3- when iron electrodes were used adversely affected the process performance. The removal efficiency with KNO3 was 49.1% at 8.33 A/m(2). Overall Cl- containing electrolytes performed well achieving almost complete decolorization (99.9%) regardless of the electrode type. The performance of Al electrode considerably improved in the presence of NH4+, achieving 98.0% and 99.1% removal efficiencies at the current densities of 4.17 A/m(2) and 8.33 A/m(2), respectively in 10 min treatment duration.Öğe Dichromate and phosphate sorption capacity of bis formyl calix[4]arene on superparamagnetic iron oxide nanoparticles in aqueous phase(Chemical Publishing Co., 2016) Ozcan, F.; Aygün, Ahmet; Sevil, U.A.; Ertul, S.Calix[4]arene derivatives were added into aqueous phase phosphate and dichromate solutions in order to investigate sorption capacity at pH of 1.5 to 5.5. A 25 mg of polymers magnetic calix[4]arenes derivatives was added into the flask shaking at 180 rpm for 1 h at room temperature. pH controls ionic forms of phosphate and dichromate, resulting in their binding capacity to the polymers. Maximum sorption capacity was 96.6 % at pH 2.5 for phosphate and 90.1 % for chromium at pH 3.5. Different polymers may be selective for ions due to their versatility and special characteristics. As a result, magnetic nanoparticle polymers showed both super-paramagnetic behaviour and high sorption capability across dichromate and phosphate ions. © 2016, Chemical Publishing Co. All rights reserved.Öğe Different methods applied to remove pollutants from real epoxy paint wastewater: modeling using the response surface method(Taylor and Francis Ltd., 2021) Adar, Elanur; Ilhan, Fatih; Aygün, AhmetComparing between classical and advanced methods for the treatment of industrial wastewater is extremely important to optimize factory operations and cost, and reduce the effects on environment. In the present study, some classical and advanced processes were assessed for chemical oxygen demand (COD) removal, the biggest problem in the wastewater from a factory producing epoxy paints. The response surface methodology was used for optimization. While the chemical coagulation (CC) and classical Fenton (CF) processes were used as the traditional methods, the electrocoagulation (EC) and electro-Fenton (EF) processes were used as the advanced methods to treat wastewater. As a result, the highest COD removal efficiencies were obtained in EF (97.8%) and CF (88.6%), respectively. Low COD removal efficiencies (43.5% and 47.5% respectively) were achieved in coagulation-based processes (CC and EC). Operating cost for CF calculated as 2.15 euro/m(3). Considering in terms of treatment efficiency, sludge volume and operating cost, CF is the most suitable option for the management of epoxy paint wastewater (EPW). These results also show that Fenton-based methods provide higher removal yields for the treatment of EPW. In other words, it is stable wastewater and the presence of hydroxyl radicals is required for its successful management.Öğe Ecological risk assessment of domestic sewage sludge: a case study(Yıldız Teknik Üniversitesi, 2021) Yakamercan, Elif; Aygün, AhmetThis study aims to evaluate potential ecological risks and heavy metal pollution in sewage sludge. For these purposes, domestic sewage sludge samples were collected for a period of one year from a wastewater treatment plant in Bursa, Turkey and analyzed for heavy metals. The average heavy metal content of the sewage sludge was wherein decreasing order of Zn>Cu>Ni>Cr>Pb>As>Se>Cd. As a whole, the concentration of heavy metals was below the limit values indicated within the agricultural land application legal standards. Correlation analysis showed a very strong correlation observed between Ni and Cr. Determining to pollution degree and potential ecological risks, some indices such as Enrichment factor (EF), Single-factor pollution index (PI), Geoaccumulation index (Igeo), Nemerow synthetic pollution index (PN), Contamination factor (Cf), Integrated pollution degree (Cd), Pollution Load Index (PLI), Monominal potential ecological risk (ER), Potential ecological risk index (RI), and the Probability of toxicity (mERM-Q) were used in this study. Based on the pollution index calculations, Zn and Se posed the highest contamination while As and Cd posed the lowest contamination. The mERM-Q values indicated that the probability of toxicity varied from 21 to 49%, while ecological indices indicated that ER (2.0-23.7) and RI (67.3-106.2) values were lower than a threshold value for all samples.Öğe Electrochemical treatment of sunflower oil refinery wastewater and optimization of the parameters using response surface methodology(Pergamon-Elsevier Science Ltd, 2020) Sharma, Swati; Aygün, Ahmet; Simsek, HalisCombined electrocoagulation (EC) + electrooxidation (EO) process was compared with electrochemical peroxidation (ECP) treatment process to treat sunflower oil refinery wastewater. The effect of applied current density, pH/H2O2 dosage, and operation time in the removal of chemical oxygen demand (COD), soluble COD, total organic carbon, and dissolved organic carbon (DOC) were studied using Box Behnken Design. In EC process, decrease in organic concentration was observed as the time and current density increased. The optimized conditions for EC process were achieved at pH 6.07 when a current density of 5.69 mA cm(-2) was applied for 18 min. The EO removed about 90% of DOC at an optimized pH of 5.27 and current density of 11.56 mA cm(-2) when operated for 400 min. The combined EC + EO process was successful compare to ECP process in removing between 90 and 95% of organic pollutant from the sunflower oil refinery wastewater. The energy consumption was calculated to compare between the process efficiency of EC + EO and ECP and found that EC + EO was more efficient process. The reaction rate followed a first order kinetics validated with a high R-2 value (0.96). (C) 2020 Elsevier Ltd. All rights reserved.Öğe Electrocoagulation of disperse dyebath wastewater: Optimization of process variables and sludge production(Korean Electrochemical Society, 2021) Aygün, Ahmet; Nas B.; Sevimli M.F.This study was conducted to investigate the effect of initial pH, current density, and electrolysis time on process performance in terms of decolorization and chemical oxygen demand (COD) removal from disperse dyebath wastewater (DDW) by mono-polar parallel laboratory scale electrocoagulation (EC) process. COD reduction of 51.3% and decolorization of 92.8% were obtained with operating cost of 0.19 €/m treated wastewater for Al-Al electrode pair, while 90.5% of decol-orization and 49.2% of COD reduction were obtained with operating cost of 0.203 €/m treated wastewater for an Fe-Fe electrode pair. The amount of sludge production were highly related to type of the electrode materials. At the3 optimum conditions, the amount of sludge produced were 0.18 kg/m and 0.28 kg/m for Al-Al and Fe-Fe electrode pairs, respec-tively. High decolorization can be explained by the hydrophobic nature of the disperse dye, while limited COD removal3 3 was observed due to the high dissolved organic matter of the DDW based on auxiliary chemicals. Energy, electrode, and chemical consumptions and sludge handling were considered as major cost items to find a cost-effective and sustainable solution for EC. The contribution of each cost items on operating cost were determined as 10.0%, 51.1%, 30.5% and 8.4% for Al-Al, and they were also determined as 9.0%, 38.0%, 40.5% and 12.5% for Fe-Fe, respectively. COD reduction and decolorization were fitted to first-order kinetic rule.Öğe Electrooxidation of nonylphenol ethoxylate-10 (NP10E) in a continuous reactor by BDD anodes: optimisation of operating conditions(Taylor & Francis Ltd, 2022) Sivri, Sabriye; Ustun, Gokhan Ekrem; Aygün, AhmetElectrooxidation (ELOX) of synthetic and real wastewater containing nonylphenol ethoxylate-10 (NP10E) surfactant as a model pollutant was investigated using a boron-doped diamond anode (BDD) in a continuous reactor in the presence of Na2SO4 or NaCl supporting electrolyte. Response surface methodology (RSM) with there factors and five coded levels (Central Composite Design, CCD) was used to optimise the continuous ELOX process performing 17 runs for each supporting electrolyte type. Individual and interactive effects of process variables such as initial pH of synthetic wastewater, current density and electrolysis time on NP10E electrooxidation were investigated in terms of COD, TOC, and NP10E removal efficiencies. It was found that NP10E to be more efficiently electrooxidized when NaCl was used as the supporting electrolyte. Under the optimal experimental conditions (initial pH 8, current density of 250 A/m(2) and electrolysis time of 45 min) for electrooxidation of synthetic wastewater, the removal efficiencies were 91.6%, 94.3% and 85.3% with the operating cost of 0.90 US$/m(3) for COD, TOC, and NP10E, respectively. In the studies conducted with real wastewater, obtained results were very close to these results. And also, kinetic studies were performed to find the reaction rate coefficient at the optimum conditions. Based on the type of supporting electrolyte the COD removal rates were fitted first order and zero-order reaction kinetic rules for Na2SO4 and NaCl, respectively.Öğe Elektrokoagülayon Yöntemiyle Reaktif Yellow 160 Boyar Maddesinin Giderimi(2017) Aygün, Ahmet; Eren, BeytullahDemir ve alüminyum elektrotlar ile donatılmış elektrokoagülasyon prosesinin (EP) kullanıldığı çalışmada Reaktif Yellow 160 (RY160) boyarmaddesi giderimi üzerine başlangıç pH, akım yoğunluğu, iletkenlik ve elektroliz süresinin etkisi incelenmiştir. EP'de elektrot materyalinden bağımsız olarak yüksek renk giderim verimi elde edilmiştir. Optimum işletme şartları alüminyum elektrot kullanılması durumunda, pH = 5, akım yoğunluğu 100 A/m2, elektroliz süresi 10 dakika, iletkenlik 1000 µS/cm iken demir elektrot kullanılması durumunda pH = 7, akım yoğunluğu 200 A/m2, elektroliz süresi 5 dakika, iletkenlik 1000 µS/cm olarak belirlenmiştir. Renk giderim verimi alüminyum elektrot çifti için 2,3 kWsa/m3 enerji sarfiyatı ve 0,52 $/m3 toplam maliyetle %96,4 iken demir elektrot çifti için 1,7 kWsa/m3 enerji sarfiyatı ve 0,28 $/m3 toplam maliyetle %95,8 elde edilmiştir. Sonuçlar, demir elektrot kullanımının alüminyum elektrot ile karşılaştırıldığında RY160 boyarmaddesinin gideriminde daha ekonomik olduğunu göstermiştir.Öğe Fate and removal of pentachlorophenol and diethylhexyl phthalate from textile industry wastewater by sequencing batch biofilm reactor: Effects of hydraulic and solid retention times(Elsevier Ltd, 2021) Yakamercan, Elif; Aygün, AhmetThis study aimed to examine the effects of hydraulic retention time (HRT) and solid retention time (SRT) on the removal of diethylhexyl phthalate (DEHP) and pentachlorophenol (PCP) from real textile wastewater. Experiments were conducted daily and at different SRTs (10 d, 15 d, and 20 d) and HRTs (36 h, 48 h, and 60 h). The results showed that the optimal HRT and SRT for DEHP removal were 48 h and 20 d, respectively, and the removal efficiency reached 83.27%. Meanwhile, the highest removal efficiency was 75.5% for PCP at an HRT of 60 h and an SRT of 15 d. The addition of biocarriers to the reactor system was intended to facilitate microorganism growth and increase the average removal efficiencies of PCP and DEHP. Short HRTs and SRTs resulted in low micropollutant removal efficiencies. Based on the mass balance calculations, it was determined that biodegradation and sorption onto sludge were the main removal mechanisms for PCP and DEHP. The findings also revealed that using the optimal HRT and SRT is critical to achieve the highest growth of the bacteria responsible for the biodegradation of selected micropollutants. In the biocarrier amended system, biodegradation served and sorption onto sludge contributed to PCP removal. Conversely, the major removal mechanism for DEHP varied depending on the operating conditions. In particular, with increasing SRT, biodegradation became the dominant removal mechanism.Öğe Impact of Chlorella vulgaris biomass substitution on in vitro bioaccessibility of cookies(International Society of Academicians, 2024) Dündar, Ayşe Neslihan; Aygün, Ahmet; Şahin, Oya IrmakThis study aimed to produce low-fat cookies (C) by substituting Chlorella vulgaris biomass (0.5% CB1, 1.0% CB2, and 1.5% CB3) and investigating the bioavailability of minerals, total phenolic content, and antioxidant capacities of the cookies. Chlorella sp. microalgae is recognized for its high phenolic content, antioxidant capacity, and as a source of essential minerals. Extractable and hydrolyzable fractions were prepared to determine the total phenolic content and antioxidant capacity. The total phenolic content of CB samples ranged from 200.82 to 274.07 mg GAE/g, with bioaccessibility values from 32.31 to 47.26 mg GAE/g. The CUPRAC method provided the highest antioxidant capacity values (116.57-154.38 µmol TE/g), while the ABTS method showed the highest bioaccessibility values (6.76-9.21 µmol TE/g). Mineral content analysis (Na, Mg, P, K, Ca, Mn, Fe, Cu, Zn, and Se) revealed significant enhancements in the CB samples compared to controls, showing an approximate 2-fold increase in mineral bioaccessibility. Despite extensive research on microalgae-fortified foods, there is a notable gap in knowledge regarding their "in vitro bioaccessibility." This study aims to pioneer the exploration of bioaccessibility and highlight the positive impact of algae-based food consumption on human health.Öğe Kirlenmiş topraklardaki p,p'-DDE'nin kabak bitki özsuyu ile ilişkili biriktirme mekanizması(2017) İşleyen, Mehmet; Eren, Beytullah; Aygün, AhmetBu araştırmada yıllanmış p,p'-DDE kirlenmiş topraklarda yetiştirilen Raven ve Zephyr kabak türlerinde, p,p'-DDE'nin topraktan bitki yapısına geçişinde bitki özsuyunun etkisini araştırmak için deneyler yürütülmüştür. Raven bitki özsuyundaki 0,21 µg/L ortalama p,p'-DDE konsantrasyonunun Zephyr bitki özsuyundaki değerle karşılaştırıldığında 10 kat daha fazla olduğu tespit edilmiştir. Buna paralel olarak, Raven ve Zephyr bitki gövdelerindeki p,p'-DDE konsantrasyonu sırasıyla 1561 µg/Kg ve 40 µg/Kg olarak belirlenmiştir. Bitki özsuyunda tesbit edilen Beyazımsı Kolloidal Yapıda Maddeler (BKYM), özsudaki p,p'-DDE miktarındaki artışa, bunun sonucunda da bitki gövdesinde daha fazla birikime sebep olacağı konusunda şüphe uyandırmıştır. Bu araştırma p,p'-DDE'nin bitki özsuyundaki BKYM ile taşındığını gösteren ilk deneysel çalışmadır.Öğe Land application of municipal sewage sludge: Human health risk assessment of heavy metals(Elsevier Ltd, 2021) Yakamercan, Elif; Ari, Akif; Aygün, AhmetLand application of municipal sewage sludge has become an attractive option and disposal method used worldwide. Hence, the suitability of the sludge with regards to toxic and carcinogenic chemicals is crucial to prompt informed decisions regarding its use on agricultural areas. This study aims to assess ecological and human health risks of heavy metals in sewage sludge samples collected from 22 different cities' wastewater treatment plants to determine their agricultural application potential in Turkey. The average metal concentrations of the samples decreased as the following order of Zn > Cu > Cr > Pb > Ni > Mo > As > Cd > Se > Hg without a significant seasonality. To evaluate the carcinogenic and non-carcinogenic health risks, site-specific overall total cancer risk (TCR) and Hazard Index (HI) values were calculated as the sum of all heavy metals’ ingestion, inhalation, and dermal contact exposures for children and adults. Contribution of the inhalation exposure due to the dust re-suspension during agricultural work to the total health risk has seemed be negligible when compared to ingestion and dermal contact. The carcinogenic risk for the adults were within the acceptable range (10−6 to 10−4) proposed by USEPA based on our estimations (2.4 ✕ 10−5), but the risk value was slightly exceeded the safe levels for children (1.6 ✕ 10−4). Similarly, HI values for adult subjects were below the reference value of 1, whereas they were higher for children (up to 2.52). Pb, As, and Cr were the major contributing metals to carcinogenic risks for both children and adults. Although the heavy metal concentration of collected samples was within the agricultural land application legal standards proposed by the Environmental Protection Agency (EPA) and the Ministry of Environment and Urbanization of Turkey (MEU), but the results of human health risk assessments showed that the risks may occur especially for sensitive individuals like children. This study showed that the evaluation of waste materials such as municipal sewage sludge should be applied only if it is proper for both ecological and health-safe, and assessing based on the regulatory limit values would not be enough to protect all population.Öğe Microplastics in Environment and Effects on Biota(Tarım ve Orman Bakanlığı Su Yönetimi Genel Müdürlüğü, 2020) Bozdaş, Kübra; Üstün, Gökhan Ekrem; Aygün, AhmetPlastics are used in many different fields because they are light, cheap and easy to process and become one of the most important commercial materials of today. The use of plastics is increasing every year, and since most of these materials are disposable and their wastes are not managed well, it brings environmental pollution problem. Particles smaller than 5 mm and known as microplastics are formed as a result of the breakdown of plastics by different processes in nature or as a result of direct use such as microbonces, textile fibers. Microplastics are ubiquitous in nature and are of concern for ecosystems. Environmental problems related with microplastic and studies on this subject have become the focus of interest in the last decade. Microplastics into receiving water from different sources poses a threat to aquatic organisms and humans. In this study, microplastics in different environments and their effects on environment and human health were reviewed.Öğe Optimization of Struvite Precipitation for Landfill Leachate Treatment(2018) Doğan, Selim; Aygün, Ahmet; Argun, Mehmet Emin; Esmeray, ErtuğrulSanitary landfill is the most preferred municipal solid waste disposal method. The production of highly polluted leachate is a major disadvantage of sanitary landfills. In this study, optimization of struvite precipitation to remove ammonium from landfill leachate was conducted by using Response Surface Methodology and central composite design. Optimum struvite precipitation conditions were determined based upon 11 runs performed in central composite design. A second-order polynomial functional model was fitted well to the results. The statistical analysis showed that two independent variables which are molar rates of Mg/N and N/P had significant effects on the ammonium removal efficiency. Maximum ammonium removal efficiency was 99.8% at a molar rate of 1.20 for Mg/N and 1.27 for N/P for a constant 9.2 pH value. The obtained results revealed that struvite used as pre-treatment in anaerobic process can be modelled by using response surface methodology. And also, response surface methodology can be used to optimize required ammonium removal efficiency for lower Mg/N and N/P molar ratio which affects the performance of pre-treatment method that designed for an anaerobic process having 300:5:1 ratio for COD/N/P.Öğe Performance of a pilot-scale reverse osmosis process for water recovery from biologically-treated textile wastewater(Academic Press Ltd- Elsevier Science Ltd, 2019) Sahinkaya, Erkan; Tuncman, Selen; Koc, Ibrahim; Guner, Ali Riza; Ciftci, Suheyla; Aygün, AhmetTextile industry generates a high volume of wastewater containing various type of pollutants. Although high color and chemical oxygen demand (COD) removals are achieved with the combination of biological and chemical treatment processes, reverse osmosis (RO) process is generally needed for water recovery due to high conductivity of the textile wastewater. In this study, a pilot scale RO process containing one spiral wound membrane element was operated under three different operational modes, i.e. concentrated, complete recycle and continuous, to collect more information for the prediction of a real-scale RO process performance. It was claimed that complete recycle mode of operation enabled mimicking the operational conditions exerted on the first membrane, whereas continuous mode of operation created conditions very similar to the ones exerted on the last membrane element in a real scale RO process train. In the concentrated and continuous mode of operation, water recovery and flux were around 70% and 19 L/m(2)/h (LMH). Permeate produced in the RO process can be safely reused in the dyeing process as the feed and permeate conductivities were around 5500 mu S/cm and 150 mu S/cm, respectively, at 70% water recovery. However, color concentration in the concentrate exceeded the discharge limits and would need further treatment. The RO performance was accurately predicted by ROSA simulations.Öğe Removal of sulphate from landfill leachate by crystallization(Korean Soc Environmental Engineers, 2019) Aygün, Ahmet; Dogan, Selim; Argun, Mehmet Emin; Ates, HavvaThe present study explores the applicability of response surface methodology (RSM) in conjunction with central composite design (CCD) matrix to statistically optimize ettringite crystallization process for the removal of sulphate from landfill leachate. A three factor-five coded level CCD with 20 runs, was performed to estimate the best fitted model. The RSM results indicated that the fitted quadratic regression model could be appropriate to predict sulfate removal efficiency. The pH was identified as the most dominant parameter affecting sulphate removal. 61.6% of maximum sulphate removal efficiency was obtained at pH of 11.06 for a 1.87 of Ca/SO4 and 0.51 of Al/SO4 molar ratios. The operating cost for ettringite crystallization at optimized conditions was calculated to be 0.52 $/m(3 ). The significance of independent variables and their interactions were tested by analysis of variance. Scanning electron microscope (SEM) and SEM coupled with energy dispersive X-Ray spectroscopy results confirmed the formation of ettringite crystal and were used to describe its morphology features.
