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Öğe A Critical Review of Contaminants of Emerging Concern in Reclaimed Wastewater: Implications for Agricultural Irrigation(Springernature, 2025) Yakamercan, Elif; Obijianya, Christian C.; Jayakrishnan, U.; Aygun, Ahmet; Velluru, Sridevi; Karimi, Mahmoud; Simsek, HalisThis critical review examines contaminants of emerging concern (CECs) in reclaimed wastewater used for agricultural irrigation, with a focus on their implications for environmental sustainability, food safety, and human and ecosystem health. Increasing water scarcity and climate change have intensified reliance on reclaimed wastewater, making a clear understanding of CEC behavior essential. Drivers of its use include technological advances, while barriers remain in the form of CEC occurrence, regulatory gaps, and public perception. The fate and transport of CECs in soil, water, and air determine their environmental risks. However, concentrations in treated wastewater from municipal/industrial wastewater treatment plants, desalination plant effluents, and others are typically low, with varying composition among similar wastewater. The incomplete removal causes leakage of CECs into reclaimed wastewater, thereby exhibiting persistence, bioaccumulation, and toxicity that can affect soil quality, plant physiology, and food safety. Plant uptake and long-term impacts depend on contaminant properties, irrigation practices, and crop species. Ecological risk assessments suggest moderate to high risks to aquatic organisms, while human health risks are generally low but may rise under worst-case exposure scenarios. Advanced treatment technologies, controlled irrigation, and soil management strategies can mitigate these risks by reducing bioavailability and enabling better monitoring. This review concludes with recommendations for researchers, practitioners, and policymakers to improve the safe and sustainable use of reclaimed wastewater in agriculture.Öğe Agricultural Irrigation Using Treated Wastewater: Challenges and Opportunities(Mdpi, 2025) Obijianya, Christian C.; Yakamercan, Elif; Karimi, Mahmoud; Veluru, Sridevi; Simko, Ivan; Eshkabilov, Sulaymon; Simsek, HalisReusing and recycling treated wastewater is a sustainable approach to meet the growing demand for clean water, ensuring its availability for both current and future generations. Wastewater can be treated in such advanced ways that it can be used for industrial operations, recharging groundwater, irrigation of fields, or even manufacturing drinkable water. This strategy meets growing water demand in water-scarce areas while protecting natural ecosystems. Treated wastewater is both a resource and a challenge. Though it may be nutrient-rich and can increase agricultural output while showing resource reuse and environmental conservation, high treatment costs, public acceptance, and contamination hazards limit its use. Proper treatment can reduce these hazards, safeguarding human health and the environment while enhancing its benefits, including a stable water supply, nutrient-rich irrigation, higher crop yields, economic development, and community resilience. On the one hand, inadequate treatment may lead to soil salinization, environmental degradation, and hazardous foods. Examining the dual benefits and risks of using treated wastewater for agricultural irrigation, this paper investigates the complexities of its use as a valuable resource and as a potential hazard. Modern treatment technologies are needed to address these difficulties and to ensure safe and sustainable use. If properly handled, treated wastewater reuse has enormous potential for reducing water scarcity and expanding sustainable agriculture as well as global food security.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 Antibiotic ciprofloxacin removal from aqueous solutions by electrochemically activated persulfate process: Optimization, degradation pathways, and toxicology assessment(Science Press, 2024) Yakamercan, Elif; Aygun, Ahmet; Simsek, HalisCiprofloxacin (CIP) is a commonly used antibiotic in the fluoroquinolone group and is widely used in medical and veterinary medicine disciplines to treat bacterial infections. When CIP is discharged into the sewage system, it cannot be removed by a conventional wastewater treatment plant because of its recalcitrant characteristics. In this study, boron-doped diamond anode and persulfate were used to degrade CIP in an aquatic solution by creating an electrochemically activated persulfate (EAP) process. Iron was added to the system as a coactivator and the process was called EAP + Fe. The effects of independent variables, including pH, Fe2 + , persulfate concentration, and electrolysis time on the system were optimized using the response surface methodology. The results showed that the EAP + Fe process removed 94% of CIP under the following optimum conditions: A pH of 3, persulfate/Fe2 + concentration of 0.4 mmol/L, initial CIP concentration 30 mg/L, and electrolysis time of 12.64 min. CIP removal efficiency was increased from 65.10% to 94.35% by adding Fe2 + as a transition metal. CIP degradation products, 7 pathways, and 78 intermediates of CIP were studied, and three of those intermediates ( m/z 298, 498, and 505) were reported. The toxicological analysis based on toxicity estimation software results indicated that some degradation products of CIP were toxic to targeted animals, including fathead minnow, Daphnia magna , Tetrahymena pyriformis , and rats. The optimum operation costs were similar in EAP and EAP + Fe processes, approximately 0.54 euro/m3 . (c) 2024 The Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V.Öğe Ardışık kesikli reaktörlerde biyotaşıyıcı ilavesinin tekstil atık suyundan pentaklorofenol (PCP) ve di(2 ethilhekzil) fitalat (DEHP) giderim verimi üzerine etkisi(Bursa Teknik Üniversitesi, 2019) Yakamercan, Elif; Aygün, AhmetTekstil endüstrisi atıksularının konvansiyonel kirleticiler dışında önemli miktarda mikrokirletici içerdiği bilinmektedir. Çok düşük konsantrasyonlarda dahi mikrokirletici deşarj edilmesi toksik ve endokrin bozucu özellikleri nedeniyle sucul ekosistem üzerinde potansiyel risk unsuru oluşturmaktadır. Bu kirleticilerin olumsuz etkilerinin en aza indirilmesi amacıyla ulusal ve uluslararası mevzuatlarda alıcı ortama deşarjında sınır değerler tanımlanmıştır. Ülkemizde 2016 yılında revize edilen Yerüstü Su Kalitesi Yönetmeliği kapsamında nehir/göl ve kıyı geçiş suları için belirlenen mikrokirleticiler için Çevresel Kalite Standardı (ÇKS) oluşturulmuştur. Demirtaş Organize Sanayi Bölgesi (DOSAB) Atıksu Arıtma Tesisi giriş atıksuyu laboratuvar ölçekli ardışık kesikli reaktör (AKR) ve biyotaşıyıcı malzeme ilavesi ile oluşturulan ardışık kesikli biyofilm reaktörün (AKBR) beslenmesinde kullanılmıştır. Tez kapsamında, konvansiyonel kirleticiler ile plastikleştiriciler grubundan, canlılar üzerinde endokrin bozucu etki gösterdiği bilinen diethilhekzilfitalat (DEHP) ve biyosit olarak yaygın bir kullanım alanı olan, toksik olduğu raporlanan pentaklorofenol (PCP) model mikrokirleticilerinin arıtım düzeyleri araştırılmıştır. Yürütülen çalışmalarda işletme şartlarının (anaerobik-aerobik döngü süreleri, hidrolik bekleme süresi ve çamur yaşı) ve biyotaşıyıcı ilavesinin arıtma performansı üzerine etkisinin ortaya konulması ve optimum işletme koşullarının belirlenmesi amaçlanmıştır. AKR ve AKBR sistemleri aktif hacmi 5 L olan reaktör sistemlerinden oluşmakla beraber toplam reaksiyon süresi 20 saat olacak şekilde işletilmiştir. Reaktörlerin işletim performansı ve çıkış suyunun kalitesi için günlük olarak konvansiyonel parametreler (KOİ, AKM, renk ve MLSS) standart metotlara göre ölçülmüş ayrıca çıkış suyu, karışık sıvı ve biyotaşıyıcılardan alınan örneklerde seçilen mikrokirleticilerin konsantrasyonları GC-MS cihazı ile belirlenmiştir. İlk olarak 4 sa. anaeobik-16 sa. aerobik (SET 1), 8 sa. anaeobik-12 sa. aerobik (SET 2), 12 sa. anaeobik-8 sa. aerobik, (SET 3), 16 sa. anaeobik-4 sa. aerobik (SET 4) olacak şekilde prosesler çalıştırılmıştır. Havalandırma süresinin artmasının DEHP gideriminin her iki proses için de arttığı ancak, AKBR daha yüksek giderim verimlerine ulaşıldığı gözlemlenmiştir. Farklı olarak PCP'nin giderimi üzerine aerobik-anaerobik döngü sürelerinin değişiminin DEHP ile kıyaslandığında daha sınırlı etki gösterdiği tespit edilmiştir. HRT değişimin mikrokirletici giderim verimi üzerine etkisinin incelenmesi için HRT 36, 48 ve 60 sa. olacak şekilde prosesler işletilirken SRT (15 gün) ve havalandırma süresi (4 sa anaerobik/16 sa aerobik) sabit tutulmuştur. HRT'nin artması ile AKR ve AKBR de model mikrokirleticilerin giderim verimlerinde artış gözlemlenmiştir. Çamur yaşının giderim verimleri üzerine etkisinin incelenmesi için diğer değişkenler sabit tutulup, SRT, 10, 15 ve 20 gün olarak sistemler çalıştırılmış ve en yüksek giderim verimi SRT'nin 20 gün olduğu işletim koşulunda bulunmuştur. DEHP ve PCP için temel giderim mekanizmaları çamura sorpsiyon ve biyobozunum iken buharlaşmanın ihmal edilecek düzeyde kaldığı gözlemlenmiştir. Seçilen mikrokirleticiler için en yüksek giderim 16 saat aerobik, HRT 60 sa ve SRT 15 olan işletim koşullarında elde edilmiş olup DEHP giderim verimi AKBR ve AKR için sırasıyla %83 ve %61,9 iken; PCP için giderim, AKBR ve AKR için sırasıyla %75,5 ve %49,9 olarak bulunmuştur. Makrokirleticiler için yapılan çalışmalarda da biyotaşıyıcı malzeme ilavesinin kirleticilerin giderim verimlerini arttırdığı görülmüştür. Anahtar kelimeler: ardışık kesikli reaktör (AKR), ardışık kesikli biyofilm reaktör (AKBR), biyolojik arıtma, DEHP, mikrokirletici, PCPÖğe Arıtılmış suların tarımsal sulamada kullanımında antibiyotiklerin taşınımı ve risk değerlendirmesi(Bursa Teknik Üniversitesi, 2025) Yakamercan, Elif; Aygün, AhmetBu tez çalışması kapsamında, günlük hayatta sıklıkla kullanılan 20 antibiyotik ve bu antibiyotiklerin 4 metaboliti olmak üzere toplamda 24 hedef kirletici seçilmiştir. Konya İleri Atıksu Arıtma tesisinden alınan ham atıksu, ikincil dereceden arıtılmış su ve ultrafiltrasyon (UF) ve çok katmanlı kum filtresi ve Ultraviole (MMF/UV) ile arıtılmış sular ve yer altı suyu, marul ve mısır bitkilerinin sulamasında kullanılmıştır. Antibiyotiklerin, sulama suyundaki varlıkları ile marul ve mısır bitkisine geçişleri değerlendirilmiştir. Bu kapsamda sulama suyu ve toprak numuneleri ile birlikte hasat sonrasında kök, gövde ve yenilebilir kısımlarına ayrılan bitkilerin sıvı kromatografi-kütle spektrometrisi (LC-MS) cihazı ile antibiyotik konsantrasyonları belirlenmiştir. Marul ve mısırın yenen kısımlarındaki antibiyotik konsantrasyonlarından çocuk ve yetişkin için sağlık riskleri hesaplanmıştır. Ayrıca alg, daphnia, balık ve topraktaki canlılar için sırasıyla sulama suyu ve topraktaki antibiyotik konsantrasyonları kullanılarak olası ekolojik riskler belirlenmiştir. Sulama sularının içme suyu olarak kullanılması ve toprağın yutulması durumları için de sağlık risk değerlendirilmesi yapılmıştır. Bu hesaplamalara ilave olarak bilgisayar üzerinde hesaplamalı similasyon ve öngörü modelleri ile antibiyotiklerin toksisiteleri değerlendirilmiştir. Hedef antibiyotik ve metabolitlerin hepsi su örneklerinde tespit edilmiş olup yer altı suyununda herhangi bir antibiyotik kalıntısı tespit edilememiştir. Su örneklerinde en yüksek antibiyotik ve metabolitlerin konsantrasyonları ham atıksuda olup 1932,77-22117,78 ng/L aralığındadır. Metabolitlerin ham atıksuda konsantrasyonu ise 185,69-1108,29 ng/L olarak bulunmuştur. Ham atıksuda en yüksek oranda bulunan antibiyotik sınıfı makrolidler (ML'ler)dir. Ortalama bazında en yüksek konsantrasyonda olan antibiyotiklerin azitromisin (AZI) klaritromisin (CLA) ve doksisiklin (DOX) olduğu tespit edilmiştir. Antibiyotiklerin giderim genel olarak sınırlı kalmakla birlikte en yüksek giderim UF prosesinde gerçekleşmiştir. Rokritromisin (ROX) tüm arıtma proseslerinde giderilememiştir. Sülfametaksazol (SMX), ROX ve klindamisin (CLI) biyolojik parçalanmaya dirençli antibiyotikler oldukları tespit edilmiştir. Arıtım prosesleri sonucunda bazı antibiyotikler için negatif giderimler gözlemlenmiştir bu durumun nedeni sorpsiyon desorpsiyon ile metabolitlerin tekrar ana bileşene dönmesi ve askıda katı maddelere tutunan antibiyotiklerin tekrar sisteme salınımıdır. Antibiyotikler, fizikokimyasal özelliklerine göre marul ve mısırda farklı taşınım dönüşüm mekanizmaları gerçekleştirir. Marul ve mısırda en yüksek oranda biriken antibiyotik sınıfları sırasıyla ML ve kinolon (QN) olmuştur. Antibiyotiklerin genel olarak bitki kökünden bitkinin diğer kısımlarına geçme eğiliminde olduğu bulunmuştur. En yüksek antibiyotik birikimleri ham atıksu ile sulanan örneklerde gözlemlenmiştir. Marulda en yüksek antibiyotik birikimi marulun yenen kısmında iken mısır için mısırın gövdesinde mısırın yenen kısmına göre daha yüksek oranda antibiyotik birikiminin olduğu tespit edilmiştir. Marul ve mısırın yenen kısımlarında antibiyotik birikimleri sırasıyla 651,52-1045,10 ng/g ve 190,06-578,24 ng/g olarak ölçülmüştür. Marul ve mısırın hasat edildiği toprakta ise antibiyotik konsantrasyonları sırasıyla 322,73-490,57 ng/g ve 148,00-263,00 ng/g olarak ölçülmüştür. Marul ve mısırın yenmesi durumunda oluşabilecek kanserojenik ve kanserojenik olmayan sağlık riskleri ile diğer ekolojik riskler değerlendirilmiştir. Çocuğun marul ve mısırı tüketmesi sonucu oluşan kanserojenik olmayan sağlık riski için elde edilen tehlike oranı (HI) değerleri sırasıyla 3,23x10-3-7,33x10-3 ve 3,07x10-3-1,17x10-2 olarak bulunmuştur. Yetişkin için ise bu değerler çocuğa göre daha düşüktür. Her iki bitkinin yenmesi durumunda da çocuk ve yetişkin için elde edilen HI değerleri sınır değerin altında kaldığından herhangi bir kanserojenik olmayan sağlık riski oluşturmayacağı öngörülmüştür. Marul ve mısırın yenmesi durumunda antibiyotik kaynaklı kanserojenik risk değerlendirmesinde ise toplam kanserojenik risk (TCR) değerleri çocuk ve yetişkin için 10-7 mertebelerinde bulunmuş olup her iki durumda da mısır ve marulun tüketimi sonucunda antibiyotik kaynaklı kanserojenik risk oluşmayacağı öngörülmüştür. Toksisite endişe yaklaşımı (TTC) ile de antibiyotiklerin insanda sağlık riski oluşturması için tüketilmesi gereken marul ve mısır miktarları tespit edilmiştir. Tespit edilen bu değerler gerçekte tüketilmekte olan verilere kıyasla oldukça yüksek olmaları nedeniyle bu yaklaşıma göre da farklı sulama suları ile sulanan marul ve mısırın yenmesi sonucu herhangi bir sağlık riski oluşmayacağı öngörülmüştür. Monte Carlo Similasyonu ile de marul ve mısırın yenmesi durumunda oluşabilecek sağlık risklerinin 100000 iterasyon sonucuna göre de antibiyotik kaynaklı sağlık risklerinin oluşmayacağı öngörülmüştür. Antibiyotik içeren suları içilmesi ve antibiyotik içeren hasat edilen toprağın yutulması durumunda oluşan sağlık riskleri değerlendirildiğinde genel olarak geri kazanılmış suların içilmesi durumunda antibiyotik kaynaklı herhangi bir sağlık riskinin olmadığı ancak mevsimsel olarak antibiyotik konsantrasyonundaki artışa bağlı olarak yüksek HI değerleri elde edilmiştir. Toprağın yutulması sonucunda da antibiyotik kaynaklı herhangi bir sağlık riski olmayacağı bulunmuştur. Daphnia, alg ve balık ile toprak canlıları için ekolojik risk değerlendirmesi yapılmıştır. En yüksek risk katsayısı (RQ) değeri ham atıksu kaynaklı olup şubat ayında elde edilmiştir. Bu değerlendirmede en yüksek RQ alg için elde edilmiş iken en düşük RQ'nun balık için elde edilmiştir.Öğe Comparative Analysis of Bacterial and Algal Treatment in Attached and Suspended Systems for Egg-Washing Wastewater Treatment(Amer Chemical Soc, 2025) Shivaram, Karthik B.; Nakatsu, Cindy H.; Yakamercan, Elif; Engel, Bernard A.; Huwe, Adam P.; Brunnquell, John; Simsek, HalisEgg-washing wastewater treatment is challenging due to high nutrients and organic matter from manure and broken eggs during washing. This study evaluated the performance of attached and suspended growth treatment systems, focusing on the impact of hydraulic retention time (HRT) on the treatment efficiency. Various rectangular and column reactors were employed, and moving bed biofilm reactor (MBBR) media and algae-bacteria consortia were used. Bacterial and bacterial-algal (Chlorella vulgaris) inocula, across different HRTs of 12, 24, and 48 h in column reactors and 2, 4, and 8 days in rectangular reactors, were tested. The reactors were aerated using a pump running at 5 psi (pounds per square inch) at room temperature. Algae-bacteria inoculum outperformed the standalone bacteria inoculum in removing both inorganic nitrogen and phosphorus. In the column reactor, total dissolved nitrogen removal peaked at 53.8% with bacterial inoculum at a 2 day HRT. Phosphorus removal exceeded 82% at a 4 day HRT in MBBR systems. Both reactor types demonstrated similar chemical oxygen demand (COD) removal rates, with up to 90% COD removal in MBBR at a 2 day HRT. When the COD loads reached 12,000 mg/L, attached growth systems showed greater resilience to these shock loads than suspended growth systems.Öğe Comprehensive understanding of electrochemical treatment systems combined with biological processes for wastewater remediation(Elsevier Sci Ltd, 2023) Yakamercan, Elif; Bhatt, Pankaj; Aygun, Ahmet; Adesope, Adedolapo W.; Simsek, HalisThe presence of toxic pollutants in wastewater discharge can affect the environment negatively due to presence of the organic and inorganic contaminants. The application of the electrochemical process in wastewater treatment is promising, specifically in treating these harmful pollutants from the aquatic environment. This review focused on recent applications of the electrochemical process for the remediation of such harmful pol-lutants from aquatic environments. Furthermore, the process conditions that affect the electrochemical process performance are evaluated, and the appropriate treatment processes are suggested according to the presence of organic and inorganic contaminants. Electrocoagulation, electrooxidation, and electro-Fenton applications in wastewater have shown effective performance with high removal rates. The disadvantages of these processes are the formation of toxic intermediate metabolites, high energy consumption, and sludge generation. To overcome such disadvantages combined ecotechnologies can be applied in large-scale wastewater pollutants removal. The combination of electrochemical and biological treatment has gained importance, increased removal performance remarkably, and decreased operational costs. The critical discussion with depth information in this review could be beneficial for wastewater treatment plant operators throughout the world.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 aquaculture wastewater effluent and optimization of the parameters using response surface methodology(Elsevier Sci Ltd, 2023) Bhatt, Pankaj; Huang, Jen-Yi; Shivaram, Karthik B.; Brown, Paul; Yakamercan, Elif; Simsek, HalisThe electrocoagulation (EC) and electrooxidation (EO) processes are employed widely as treatment processes for industrial, agricultural, and domestic wastewater. In the present study, EC, EO, and a combination of EC + EO were evaluated as methods of removing pollutants from shrimp aquaculture wastewater. Process parameters for electrochemical processes, including current density, pH, and operation time were studied, and response surface methodology was employed to determine the optimum condition for the treatment. The effectiveness of the combined EC + EO process was assessed by measuring the reduction of targeted pollutants, including dissolved inorganic nitrogen species, total dissolved nitrogen (TDN), phosphate, and soluble chemical oxygen demand (sCOD). Using EC + EO process, more than 87% reduction was achieved for inorganic nitrogen, TDN, and phosphate, while 76.2% reduction was achieved for sCOD. These results demonstrated that the combined EC + EO process provided better treatment performance in removing the pollutants from shrimp wastewater. The kinetic results suggested that the effects of pH, current density, and operation time were significant on the degradation process when using iron and aluminum electrodes. Comparatively, iron electrodes were effective at reducing the half-life (t1/2) of each of the pollutants in the samples. The application of the optimized process parameters on shrimp wastewater could be used for large-scale treatment in aquaculture.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 Health risk assessment of metal(loid)s for land application of domestic sewage sludge in city of Bursa, Turkiye(Springer, 2023) Yakamercan, Elif; Aygun, AhmetThis study aims to determine the potential health risks (Carcinogenic and non-carcinogenic) of metal(loid)s in sewage sludge samples for agricultural purposes. For this purpose, sewage sludge was collected annually from a domestic wastewater treatment plant, and metal(loid)s were determined by ICP-MS. Metal(loid)s concentration in sludge samples was within the legal standards. No statically significant seasonal variation of metal(loid)s were observed. The total cancer risk and the hazard index (HI) of metal(loid)s through ingestion, dermal, and inhalation exposure from sewage sludge samples were estimated. The main risk contributor to metal(loid)s were Pb, Zn, and Ni. The average HI values were 0.75 (child) and 0.09 (adult). The total carcinogenic risk (TCR) for child and adult was found to be 3.43 x 10(-5) and 2.31 x 10(-5), respectively. EPA risk assessment model and Monte Carlo Simulation were used to estimate probability and sensitivity distributions for carcinogenic and non-carcinogenic risks. Sensitivity analysis showed that metal(loid)s concentration, exposure duration, exposure frequency, and body weight significantly affect total health risk. The sewage sludge can be applied safely in agriculture due to no important carcinogenic and non-carcinogenic risk for child and adult.Öğe Improving microalgae harvesting efficiency: electrochemical techniques and parameter optimization(Royal Soc Chemistry, 2025) Yakamercan, Elif; Guleria, Samriti; Karimi, Mahmoud; Aygun, Ahmet; Bhasin, Aparajita; Simsek, HalisThe harvesting microalgae is a challenging process that requires innovative and efficient technologies to make large-scale cultivation economically viable. This study investigated the effectiveness of electrochemical methods for harvesting microalgae Chlorella vulgaris. The operational parameters, such as electrolysis time, electrical current, and pH, were optimized using the response surface methodology based on the Box-Behnken design. The boron-doped diamond (BDD), aluminum (Al), and iron (Fe) electrodes were tested and compared. BDD-Al showed 99.3% of harvesting efficiency (time: 20 min, current: 100 mA, pH: 9), which is the highest value and a pH of 9. The physicochemical properties of the harvested algae, including lipids, proteins, carbohydrates, total suspended solids, and chlorophyll-a content, were examined. The content of harvested algae was found as 41.07-46.63% for protein, 5.5-16.9% for lipid, and 9.02-12.08% for carbohydrates (sugar). The chlorophyll-a concentrations varied from 6.7 to 8.36 mu g mL-1. Optimized operating conditions for electrolysis time, pH, and current were determined, and harvesting efficiency was achieved at more than 99%. Energy consumptions for the highest harvesting efficiencies were found to be 0.2, 0.35, and 0.4 kWh kg-1 for BDD-Al, Al-Al, and Al-BDD electrode pairs, respectively. These values were lower than those of conventional algae harvesting methods. The results showed that the electrochemical harvesting techniques are promising alternatives with a high harvesting efficiency and low energy consumption.Öğe Kükürt bazlı ototrofik ve metanol bazlı heterotrofik denitrifikasyon süreçlerinin çevresel etkileri(Pamukkale Üniversitesi, 2022) Yakamercan, Elif; Uçar, DenizDenitrifikasyonda inorganik elektron vericilerinin kullanılması, organik elektron vericilerine göre düşük maliyetli ve daha az atık organik kirlenme riski gibi avantajları nedeniyle popülerlik kazanmaktadır. Kükürt, ototrofik denitrifikasyonda yaygın olarak kullanılmaktadır, ancak asit ve sülfat üretimi, ana dezavantajlarıdır. Gerekli alkaliniteyi sağlamak için kireçtaşı veya çözünmüş alkalinite kaynakları kullanılır. Bu çalışmada, çevresel etkilerini (abiyotik tükenme, küresel ısınma potansiyeli, ozon tabakasının incelmesi, insan toksisitesi, tatlı su sucul ekotoksisitesi, deniz suyu ekotoksisitesi, karasal ekotoksisite, fotokimyasal oksidasyon (POCP), asitleşme ve ötrofikasyon) belirlemek için üç denitrifikasyon işleminin (kireçtaşı destekli S0 bazlı, bikarbonat bazlı S0 bazlı ve metanol bazlı denitrifikasyon) yaşam döngüsü değerlendirmesi (YDD) yapılmıştır. Bu çalışmada YDD için, SimaPro 9.1.1 yazılımının CML 1A baseline, su ayak izi için ise AWARE V1.03 metodu kullanılmıştır. Her üç grupta da başarıyla 25 mg NO3 - -N/L giderimi sağlanmış, ancak S0 bazlı denitrifikasyonda alkalinite kaynağı olarak NaHCO3'ün kullanılması durumunda çevresel etkinin diğer proseslere göre daha yüksek olduğu belirlenmiştir. YDD ‘ye göre çevresel etkinin en düşük olduğu durum kükürtün elektron kaynağı olarak ve kireçtaşının alkalinite kaynağı olarak kullanılmasında gerçekleşmiştir. En yüksek çevresel etki elektrik kullanımı kaynaklı olup, bikarbonat beslemeli grupta toplam 75.38 kg CO2 eşdeğerindeki küresel ısınma potansiyelinin 65 kg’lık kısmı elektrik kullanımından kaynaklanmaktadır. Hetetrofik denitrifikasyonda 1 kg NO3 - -N/m3 fonksiyonel birim için su ayak izi 24.3 m3 iken kireçtaşı ve bikarbonat bazlı ototorofiklerde sırasıyla 30.7 m3 ve 45.1 m3 tir. Çalışma, ototrofik denitrifikasyonun maliyet ve su kalitesi açısından heterotrofik denitrifikasyona göre avantajları olmasına rağmen, alkalinite kaynağı olarak NaHCO3 kullanımından kaçınılması gerektiğini göstermektedir.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 Optimizing electrochemical methods for fish wastewater treatment in recirculating aquaculture systems(Elsevier, 2024) Yakamercan, Elif; Turco, Ronald F.; Nas, Bilgehan; Hussain, Aya S.; Aygun, Ahmet; Meador, Leland; Simsek, HalisAquaculture operations generate substantial wastewater containing organic matter, total dissolved solids, emerging contaminants, and uneaten food pellets, leading to significant environmental issues. In this study, electrooxidation (EO) treatment methods using a boron-doped diamond (BDD) electrode was employed to remove soluble chemical oxygen demand (sCOD), ammonia (NH3-N), nitrate (NO3--N), nitrite (NO2--N), total dissolved phosphorus (TDP), and total dissolved nitrogen (TDN) from aquaculture wastewater. Response surface methodology (RSM) was used to design experiments and optimize operating parameters. The experiments were tested as follows; pH of 6-8, current density of 30-50 mA/cm(2), and electrolysis time of 20-60 min. The results showed that >93 % removal of NH3-N, NO3--N, NO2--N, TDN, and 86.85 % of sCOD were achieved. TDP removal rate was lower than compared to other pollutants and was found to be 79.41 %. The model estimation values and experimental values agreed with an average coefficient of determination (R-2) of >0.98, and all models were found significant (p < 0.05). The optimized treatment conditions were a pH of 6.97, a current density of 42.36 mA/cm(2), and an electrolysis time of 60 min. Under these conditions, responses were achieved at 87.86, 96.52, 99.18, 94.71, 94.78, and 77.78 % for sCOD, NO2--N, NH3-N, NO3--N, TDN, and TDP. In addition, the kinetic model results confirmed that the operating parameters provided a significant reduction of parameters in the EO process. The results indicated that the EO process can efficiently treat the aquaculture effluent.Öğe Solid waste management practices in Türkiye to achieve the UN sustainable development goals of waste to energy(Elsevier, 2024) Yakamercan, Elif; Gökhan Özdemir, M.; Senapathy, MarisennayyaSolid waste has become an essential problem due to cities' rising populace and development. Solid waste management (SWM) can be a complicated process in developing nations such as Türkiye due to the difficulty of collection, storage, and disposal of high amounts of solid waste. To overcome this challenge, SWM is critical. Türkiye has established high standards to handle solid waste effectively and achieve sustainable development. Türkiye strives to promote sustainability through SWM at the local level, with initiatives focused on improving infrastructure, waste reduction and segregation, and awareness-raising campaigns. Achieving these goals will require continued investment and innovation, but Türkiye is progressing toward a more sustainable future through effective SWM. This chapter aims to evaluate the situation of SWM with a sustainability approach in Türkiye. The current status and waste-to-energy options are discussed. Future perspectives and challenges of SWM based on a sustainability approach are determined. © 2024 Elsevier Ltd. All rights reserved.Öğe Treatment of textile industry effluents with up-flow anaerobic sulfidogenic reactor(Wiley, 2024) Ozkaymak, Gulayse; Sahan, Aybuke Nur; Yakamercan, Elif; Cakmak, Yakup; Ucar, DenizBACKGROUNDDyes present in textile wastewater can pose various environmental problems, including toxicity, carcinogenicity and mutagenicity, when released into receiving environments. Sulfidogenic bacteria play a crucial role in wastewater treatment by reducing sulfate and producing sulfide through the utilization of organic compounds in water. The resulting sulfide often transfers its electrons to another electron acceptor. This study focused on the treatment of real textile wastewater using an up-flow sulfidogenic column bioreactor.RESULTSThe reactor was acclimated to sulfate-reducing conditions when influent chemical oxygen demand and sulfate concentrations were 1742 and 2000 mg L-1, respectively. Subsequently, a gradual transition was made from sulfate-reducing conditions to dye-reducing conditions. Throughout the study, the hydraulic retention time was maintained at 1 day.CONCLUSIONThe influent dye concentration was 2722 Pt-Co, and an impressive dye removal efficiency of approximately 90 +/- 2% was achieved. This corresponds to a removal rate of 2450 Pt-Co L-1 day-1. Although the sulfide concentration in the reactor decreased in the last period, investigating the extent to which this sulfide participates in the dye removal may expand the use of sulfidogenic reactors in the treatment of real textile industry wastewater. (c) 2024 The Author(s). Journal of Chemical Technology and Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry (SCI).
