Person: TUĞTAŞ KARNABAT, ADİLE EVREN
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TUĞTAŞ KARNABAT
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ADİLE EVREN
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Publication Metadata only Bio-electrochemical post-treatment of anaerobically treated landfill leachate(ELSEVIER SCI LTD, 2013) TUĞTAŞ KARNABAT, ADİLE EVREN; Tugtas, A. Evren; Cavdar, Pelin; Calli, BarisBio-electrochemical treatment of anaerobically pre-treated landfill leachate was investigated in batch and continuous-flow two-chambered microbial fuel cells (MFCs). A high strength young landfill leachate was pre-treated using an upflow anaerobic sludge blanket reactor and the effluent resembling medium-aged landfill leachate was fed to the anode chamber of MFCs. The highest maximum current and power densities achieved in continuous-flow MFC with hydraulic retention time (HRT) of five days were 525 mA/m(2) (8227 mA/m(3)) and 158 mW/m(2) (2482 mW/m(3)), respectively. Increase of HRT from one day to five days resulted in the occurrence of partial nitrification, where influent ammonia was converted into nitrite presumably due to the inhibitory effects of free ammonia. The maximum power and current densities obtained in this study were higher compared to other studies with similar leachate characteristics. The results of this study suggest that MFCs can be exploited as a polishing step for anaerobically pre-treated landfill leachate. (C) 2012 Elsevier Ltd. All rights reserved.Publication Metadata only Removal of heavy metals from leaching effluents of sewage sludge via supported liquid membranes(ELSEVIER, 2019) TUĞTAŞ KARNABAT, ADİLE EVREN; Yesil, H.; Tugtas, A. E.Heavy metal content of sewage sludge is one of the factors preventing its agricultural use. Leaching processes have been used to solubilize heavy metals and thus reduce metal content of the sludge through chemical or biological routes. Subsequent to leaching processes, metal removal from the supematant is attractive in terms of decreasing metal content of the effluent and recovering metals. This paper investigates application of supported liquid membrane (SLM) technology for metal removal from leaching effluents. SLM system was first optimized using synthetic metal mixtures. Optimized system was then used for the anaerobic bioleaching and chemical leaching effluents and metal removal efficiencies of 27.1 +/- 1.3% and 46.0 +/- 4.3% were obtained, respectively. Considering integrated leaching and membrane separation processes, metal removal efficiencies obtained in this study are valuable as it will decrease the metal content of sludge and increase the metal solubilization during leaching process. Future integration of metal leaching and removal technologies would make it possible to develop a sustainable system involving heavy metal removal from sewage sludge, land application of the sludge with a low metal content, and metal recovery. (C) 2019 Elsevier B.V. All rights reserved.Publication Metadata only Extent of bioleaching and bioavailability reduction of potentially toxic heavy metals from sewage sludge through pH-controlled fermentation(PERGAMON-ELSEVIER SCIENCE LTD, 2021) TUĞTAŞ KARNABAT, ADİLE EVREN; Yesil, Hatice; Molaey, Rahim; Calli, Baris; Tugtas, Adile EvrenUtilization of anaerobically stabilized sewage sludge on arable lands serve as a renewable alternative to chemical fertilizers as it enables recycling of valuable nutrients to food chain. However, probable pres-ence of heavy metals in sewage sludge restricts the use of stabilized sludge on lands. In this study, a novel approach based on pH-controlled fermentation and anaerobic metal bioleaching was developed to reduce ecotoxicity potential of fermented sludge prior to its land application. Sewage sludge was sub-jected to pH-controlled fermentation process at acidic, neutral, and alkaline pH levels with the aim of increasing metal solubilization and decreasing bioavailable metal fractions through anaerobic bioleaching. Alkaline reactor performed the best among all reactors and resulted in 3-fold higher hydrolysis (34%) and 6-fold higher acidification (19%) efficiencies along with 43-fold (in average) higher metal solubiliza-tion than that of neutral pH reactor. As a result of alkaline fermentation, 32-57% of the metals remained as bioavailable and 34-59% of the metals were encapsulated as non-bioavailable within solid fraction of fermented sludge (biosolid), whereas 8-12% of total metal was solubilized into fermentation liquor. Our results reveal that anaerobic bioleaching through alkaline fermentation enables biosolid production with less metal content and low bioavailability, facilitating its utilization for agricultural purposes. (c) 2021 Elsevier Ltd. All rights reserved.Publication Metadata only Recovery of mixed volatile fatty acids from anaerobically fermented organic wastes by vapor permeation membrane contactors(ELSEVIER SCI LTD, 2018) TUĞTAŞ KARNABAT, ADİLE EVREN; Aydin, Senem; Yesil, Hatice; Tugtas, A. EvrenVolatile fatty acids (VFAs) are attractive compounds in renewable based bio-refinery industries and can be produced through anaerobic digestion of organic wastes. Nevertheless, the recovery of VFAs from anaerobically digested organic wastes is the bottleneck of the resource recovery. In this study, VFA recovery from synthetic VFA solutions and fermented organic wastes via air-filled and tertiary amine extractant-filled PTFE membranes through vapor pressure membrane contactors (VPMC) was investigated. Acetic acid was recovered with greater than 45% efficiency in all the fermented wastes. Recovery of propionic, butyric, valeric, and caproic acids through trioctylamine-filled PTFE membrane was greater than 86% and 95% from landfill leachate and fermentation broth of anaerobically digested organic waste, respectively. This study reveals that VFA separation can be effectively achieved via economic and environmental friendly VPMC system and the process is implementable as it can be coupled to a fermentation process to prevent inhibition and to recover VFAs.Publication Metadata only A hybrid dry-fermentation and membrane contactor system: Enhanced volatile fatty acid (VFA) production and recovery from organic solid wastes(PERGAMON-ELSEVIER SCIENCE LTD, 2021) TUĞTAŞ KARNABAT, ADİLE EVREN; Yesil, Hatice; Calli, Baris; Tugtas, Adile EvrenAnaerobic dry-fermentation of food wastes can be utilized for the production of volatile fatty acids (VFA). However, especially for high load fermentation systems, accumulation of VFAs may result in inhibition of fermentation process. In this study, separation of VFAs from synthetic mixtures via a vapor permeation membrane contactor (VPMC) system with an air-filled polytetrafluoroethylene (PTFE) membrane was assessed at various temperatures and permeate solution concentrations. In addition, a pioneering integrated leach-bed fermentation and membrane separation system was operated with undefined mixed culture for the purpose of enhanced VFA production along with its recovery. Hybrid system resulted in 42% enhancement in total VFA production and 60% of total VFAs were recovered through the VPMC system. The results of this study revealed that integrated system can be exploited as a means of increasing organic loading to fermentation systems and increasing the value of VFA production. (c) 2021 Elsevier Ltd. All rights reserved.Publication Metadata only Acidogenic fermentation of municipal solid waste and its application to bio-electricity production via microbial fuel cells (MFCs)(IWA PUBLISHING, 2011) TUĞTAŞ KARNABAT, ADİLE EVREN; Cavdar, P.; Yilmaz, E.; Tugtas, A. E.; Calli, B.Acidogenic fermentation of organic municipal solid waste (MSW) and the bio-electricity production potential from its volatile fatty acid (VFA)-rich leachate using an air-cathode microbial fuel cell (MFC) was investigated in this study. The acidogenic fermentation of 2 kg of MSW has been carried out in a 6 L anaerobic leach-bed reactor (LBR) under mesophilic conditions (30 degrees C). Total production of 92 g VFA expressed as chemical oxygen demand (COD) in 3 L leachate mainly containing acetic, propionic, butyric, and valeric acids has been achieved with manual leachate recirculation and without pH control in 74 days of incubation. Leachate collected on day 32 was used as a feed to an air-cathode MFC after being diluted and supplemented with NaCl or NaHCO3. The maximum power density in the diluted leachate was only 5.9 W/m(3), but reached up to 8.6 W/m(3) upon the addition of 7 mmol/L NaCl. Increase in coulombic efficiency from 6 to 22% was also observed as a result of NaCl supplementation. On the other hand, NaHCO3 addition did not improve the power output.Publication Metadata only Sulfide and methane production in sewer sediments: Field survey and model evaluation(PERGAMON-ELSEVIER SCIENCE LTD, 2016) TUĞTAŞ KARNABAT, ADİLE EVREN; Liu, Yiwen; Tugtas, A. Evren; Sharma, Keshab R.; Ni, Bing-Jie; Yuan, ZhiguoSewer sediment processes have been reported to significantly contribute to overall sulfide and methane production in sewers, at a scale comparable to that of sewer biofilms. The physiochemical and biological characteristics of sewer sediments are heterogeneous; however, the variability of in-sediments sulfide and methane production rates among sewers has not been assessed to, date. In this study, five sewer sediment samples were collected from two cities in Australia with different climatic conditions. Batch assays were conducted to determine the rates of sulfate reduction and methane production under different flow velocity (shear stress) conditions as well as under completely mixed conditions. The tests showed substantial and variable sulfate reduction and methane production activities among different sediments. Sulfate reduction and methane production from sewer sediments were confirmed to be areal processes, and were dependent on flow velocity/shear stress. Despite of the varying characteristics and reactions kinetics, the sulfate reduction and methane production processes in all sediments could be well described by a one-dimensional sewer sediment model recently developed based on results obtained from a laboratory sewer sediment reactor. Model simulations indicated that the in-situ contribution of sewer sediment emissions could be estimated without the requirement of measuring the specific sediment characteristics or the sediment depths. (C) 2015 Elsevier Ltd. All rights reserved.Publication Open Access Conceptual system for sustainable and next-generation wastewater resource recovery facilities(2023-08-10) YEŞİL, HATİCE; TUĞTAŞ KARNABAT, ADİLE EVREN; ÇALLI, BARIŞ; Owusu-Agyeman I., Plaza E., Elginöz N., Atasoy M., Khatami K., Perez-Zabaleta M., Cabrera-Rodríguez C., YEŞİL H., TUĞTAŞ KARNABAT A. E., ÇALLI B., et al.Shifting the concept of municipal wastewater treatment to recover resources is one of the key factors contributing to a sustainable society. A novel concept based on research is proposed to recover four main bio-based products from municipal wastewater while reaching the necessary regulatory standards. The main resource recovery units of the proposed system include upflow anaerobic sludge blanket reactor for the recovery of biogas (as product 1) from mainstream municipal wastewater after primary sedimentation. Sewage sludge is co-fermented with external organic waste such as food waste for volatile fatty acids (VFAs) production as precursors for other bio-based production. A portion of the VFA mixture (product 2) is used as carbon sources in the denitrification step of the nitrification/denitrification process as an alternative for nitrogen removal. The other alternative for nitrogen removal is the partial nitrification/anammx process. The VFA mixture is separated with nanofiltration/reverse osmosis membrane technology into low-carbon VFAs and high-carbon VFAs. Polyhydroxyalkanoate (as product 3) is produced from the low-carbon VFAs. Using membrane contactor-based processes and ion-exchange techniques, high-carbon VFAs are recovered as one-type VFA (pure VFA) and in ester forms (product 4). The nutrient-rich fermented and dewatered biosolid is applied as a fertilizer. The proposed units are seen as individual resource recovery systems as well as a concept of an integrated system. A qualitative environmental assessment of the proposed resource recovery units confirms the positive environmental impacts of the proposed system.Publication Metadata only Removal and recovery of heavy metals from sewage sludge via three-stage integrated process(PERGAMON-ELSEVIER SCIENCE LTD, 2021) TUĞTAŞ KARNABAT, ADİLE EVREN; Yesil, Hatice; Molaey, Rahim; Calli, Baris; Tugtas, Adile EvrenHeavy metal contamination of sewage sludge is one of the concerns preventing its land application. Traditional processes applied for stabilization of sewage sludge are still inadequate to serve sustainable solutions to heavy metal problem. In this study, fermentation and bioleaching potentials of sewage sludge were investigated in anaerobic reactors for either non-pretreated or ultrasonicated sludge at three different pH regimes (free of pH regulation, acidic, and alkaline). The results of the study revealed that combination of ultrasonication pretreatment and alkaline fermentation performed the best among the other cases, resulting in 33.7% hydrolysis, 10.5% acidification, 11-33% metal leaching, and up to 25% reduction in bioavailability of potentially toxic heavy metals. Bioleaching effluent obtained from the best performing reactor was subjected to membrane-based metal recovery. A supported liquid membrane impregnated with a basic carrier successfully recovered soluble metals from the bioleaching effluent with an efficiency of 39-68%. This study reveals that the proposed three-stage process, ultrasonication pretreatment-alkaline fermentation-supported liquid membrane, effectively produces stable sludge with reduced heavy metal toxicity and recovers metals from organic waste streams. (C) 2021 Elsevier Ltd. All rights reserved.Publication Metadata only Enhanced heavy metal leaching from sewage sludge through anaerobic fermentation and air-assisted ultrasonication(PERGAMON-ELSEVIER SCIENCE LTD, 2021) TUĞTAŞ KARNABAT, ADİLE EVREN; Molaey, Rahim; Yesil, Hatice; Calli, Baris; Tugtas, Adile EvrenInterest in using stabilized sewage sludge in agriculture is mainly to benefit from its nutrient content, soil conditioning properties, and water holding capacity. Therefore, sludge management practice needs to be directed from treatment liability towards the recovery of chemical assets embedded in sludge. In this study, anaerobic fermentation process integrated with a new treatment method; i.e., air-assisted ultra-sonication, was used to assess the leaching of heavy metals (HM) from waste activated sludge (WAS). Fermentation processes resulted in 9390 mg COD/L of volatile fatty acids (VFAs) production, 26% Ni solubilization and up to 3.4% solubilization of other target metals (Cu and Zn). Application of the air-assisted ultrasonication as a post-treatment to fermentation process stimulated the migration and transformation of HMs to the liquid fraction of the digestate. Applying specific energy input greater than 9 kJ/g total solids (TS) through ultrasonication and supplying air with constant flow rate of 0.875 L of air/(L of digestate.min) resulted in leaching of more than 83% of Ni, 82% of Cu and 80% of Zn. (C) 2021 Elsevier Ltd. All rights reserved.