Yazar "Simsek, Halis" seçeneğine göre listele
Listeleniyor 1 - 10 / 10
Sayfa Başına Sonuç
Sıralama seçenekleri
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 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 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 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 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 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 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 Organic pollutant removal from edible oil process wastewater using electrocoagulation(Iop Publishing Ltd, 2018) Sharma, Swati; Can, Orhan Taner; Hammed, Monsur; Nawarathna, Dharmakeerthi; Simsek, HalisWastewaters generated from vegetable oil industries contain a high concentration of organic pollutants that are detrimental to the aquatic ecosystem. Electrochemical processes are gaining importance in the treatment of inorganic and resistant organic pollutants in wastewaters. In this study, electrocoagulation (EC) was applied to remove organic pollutants and oil and grease from canola oil wastewater using aluminum (Al) and iron (Fe) electrodes. The application of EC in the wastewater achieved more than 80% removal of organic carbon and nearly 100% removal of suspended solids (SS). The effectiveness of EC is influenced mainly by current density, pH, electrolyte (NaCl), electrode contact time and electrode type. It was observed that Al electrode combination yielded better removal at a lesser time compared to that of Fe electrodes. However, varying current densities had its significance in terms of coagulation time only. Increase in current density achieved decrease in coagulation time. Both Al and Fe could remove between 52-59% of oil and grease from canola oil wastewater
