Person: ÇALLI, BARIŞ
Loading...
Email Address
Birth Date
Research Projects
Organizational Units
Job Title
Last Name
ÇALLI
First Name
BARIŞ
Name
8 results
Search Results
Now showing 1 - 8 of 8
Publication Metadata only Monitoring of population shifts in an enriched nitrifying system under gradually increased cadmium loading(ELSEVIER SCIENCE BV, 2008) ÇALLI, BARIŞ; Mertoglu, Bulent; Semerci, Neslihan; Guler, Nuray; Calli, Baris; Cecen, Ferhan; Saatc, Ahmet MeteThe changes in nitrifying bacterial population under cadmium loading were monitored and evaluated in a laboratory scale continuous-flow enriched nitrification system. For this purpose, the following molecular microbiological methods were used: slot-blot hybridization, denaturing gradient gel electrophoresis (DGGE), real-time PCR followed by melting curve analysis, cloning and sequence analysis. The initial cadmium concentration was incrementally increased from 1 to 10mg/l which led to a drop in ammonia removal efficiency from 99 to 10%. inhibition was recovered when cadmium loading was stopped. During the second application of cadmium. nitrifying population became more tolerant. Even at 15 mg/l Cd, only a minor inhibition was observed. To investigate the variations in ammonia and nitrite oxidizing bacteria populations in a period of 483 days, ammonia monooxygenase (amoA) and 16S rRNA genes-based molecular techniques were used. An obvious shift was experienced in the diversity of ammonia oxidizers after the first application of 10mg/l Cd. Metal-tolerant ammonia oxidizing species became dominant and the microbial diversity sharply shifted from Nitrosomonas and Nitrosococcus sp. to Nitrosospira sp. which were observed to tolerate higher cadmium loadings. This result indicated that the extent of nitrification inhibition was not only related to the metal concentration and quantity of microorganisms but also depended on the type of species. (C) 2008 Elsevier B.V. All rights reserved.Publication Metadata only Anaerobic digestion of chicken manure by a leach-bed process coupled with side-stream membrane ammonia separation(ELSEVIER SCI LTD, 2018) ÇALLI, BARIŞ; Bayrakdar, Alper; Surmeli, Recep Onder; Calli, BarisThis study pioneered the use of a single-stage methanogenic leach bed reactor (LBR) for high-solids (total solid content: 14%-16%) anaerobic mono-digestion of chicken manure. Chicken manure was loaded into the LBR in cloth sachets without adding any bulking agents. Ammonia was separated and recovered by placing a hydrophobic gas diffusion membrane in a leachate collection chamber. Methane production in the membrane-integrated LBR was 0.272 m(3)/kgVS and 2.3 times higher than that in the control LBR. The results revealed that using membrane-integrated LBR for anaerobic digestion is a simple and cost-efficient technology for the monodigestion of chicken manure and ammonia removal.Publication Metadata only Effect of Operating Conditions on Separation of H2S from Biogas Using a Chemical Assisted PDMS Membrane Process(SPRINGER, 2018) ÇALLI, BARIŞ; Tilahun, Ebrahim; Sahinkaya, Erkan; Calli, BarisHydrogen sulfide (H2S) is an undesirable impurity that has to be removed from biogas to avoid the corrosion of co-generation units. In the present study, we evaluated the potential of a gas-liquid membrane contactor process for selective removal of H2S from biogas. The effects of biogas retention time (GRT), membrane thickness and liquid absorbent pH were investigated. A dilute sodium hydroxide solution was used as absorbent. The results revealed that H2S removal efficiency (RE) improved with increasing GRT and absorbent pH, and decreased with increasing membrane thickness. When GRT reduced from 19 to 3.4min, the RE of H2S and CO2 decreased by over 2.5 and 5.2 times, respectively. In contrast, a higher desulfurization selectivity was observed with lower GRT and thicker membranes. The CH4 content of the treated biogas increased along with increasing GRT and was enriched from 60% to a maximum of 87% with only 4.68% loss. The SEM-EDS analysis confirmed the deposition of inorganics such as Ca, Mg, S and Si on the membrane surface. However, any membrane clogging and fouling problem was not observed. In summary, the novel gas-liquid polydimethylsiloxane membrane contactor tested in this study has performed well in selective removal of H2S from biogas and is expected to be a promising alternative to conventional desulfurization processes.Publication Metadata only Ammonia recovery from chicken manure digestate using polydimethylsiloxane membrane contactor(ELSEVIER SCI LTD, 2018) ÇALLI, BARIŞ; Surmeli, Recep Onder; Bayrakdar, Alper; Calli, BarisThe ammonia removal and recovery performance of a non-porous tubular PDMS membrane was evaluated in this study by immersing it into chicken manure (CM) digestate and operating it in sweep gas mode at different air flowrates, pH values and total ammonium nitrogen (TAN) concentrations. The TAN removal flux achieved as 1.33 +/- 0.10 g/m(2)/day was comparable to the values obtained with porous membranes used in ammonia recovery from anaerobic digestate. The relative proportion of ammonium and free ammonia, which depends on pH, temperature and TAN concentration of digestate, was found to be more effective than the sweep gas flow rate on ammonia recovery. In this study, it was shown for the first time that the low cost non-porous tubular PDMS membrane contactor is a promising technology for recovery of ammonia from nitrogen rich wastes such as CM digestate. (C) 2018 Elsevier Ltd. All rights reserved.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 Recovery of phosphorus from liquid digestate using waste magnesite dust(ELSEVIER SCI LTD, 2020) ÇALLI, BARIŞ; Al-Mallahi, Jumana; Surmeli, Recep Onder; Calli, BarisPhosphorus recovery through struvite precipitation consumes significant amounts of magnesium, thereby increasing the total cost of the process. Therefore, it is important to find cheaper alternatives than commercial magnesium sources. Processing of magnesite ore to produce magnesium oxide generates waste, the disposal of which can give associated environmental problems. Conversely, this 'waste' material might serve as an appropriate source of magnesium and also as a pH elevator. This study proposes calcination of Waste Magnesite Dust (WMD) to enhance its magnesium release. Calcination was carried out at 500 degrees C, 700 degrees C, 800 degrees C and 900 degrees C for different durations. Fluidized Bed Reactor (FBR) experiments were undertaken to evaluate the performance of calcined WMD compared to raw WMD. This was followed by batch experiments to determine the effect of dosage and pH on phosphorus recovery and to compare the calcined WMD with pure magnesium oxide (MgO). The optimum reaction time was evaluated by running a FBR experiment at optimum dosage. Finally, cost analysis was performed. Complete decomposition could be achieved by calcining at 700 degrees C, 800 degrees C and 900 degrees C for 1, 0.5 and 0.25 h respectively. Calcination converted magnesite to magnesia and enhanced magnesium release. Optimum precipitation conditions were identified to comprise a dosage of 1 g/L of calcined WMD and a reaction duration of 2 h for liquid fraction digestate. Phosphorus removal of 96% for synthetic solution and 75% for real digestate was achieved by WMD which was completely decomposed at 900 degrees C for 0.25 h. Cost analysis revealed the advantage of applying WMD calcined at 700 degrees C for 1 h, which resulted in the highest cost reduction; 38% and 57% compared to magnesium oxide and magnesium chloride respectively. It is considered that this might increase the profitability of magnesite processing companies through allowing them to sell this material, for subsequent use as a cheaper magnesium source for struvite precipitation. (C) 2020 Elsevier Ltd. All rights reserved.Publication Metadata only Dry anaerobic digestion of chicken manure coupled with membrane separation of ammonia(ELSEVIER SCI LTD, 2017) ÇALLI, BARIŞ; Bayrakdar, Alper; Surmeli, Recep Onder; Calli, BarisIn this study, the anaerobic digestion of egg-laying hen manure combined with membrane-based ammonia separation was investigated. Long-term continuous experiments with and without ammonia separation were performed by increasing the organic loading rate (OLR). Although the control digester was completely inhibited at an OLR and influent total Kjeldahl nitrogen (TKN) concentration of 3.85 kgVS/m(3).d and 8.2 g/l, respectively, an average methane yield of 0.30 +/- 0.02 m(3)/kgVS was achieved with a membrane-integrated digester at an OLR and influent TKN concentration of 6.0 kgVS/m(3).d and 15 g/l, respectively. When the ammonia concentration increased above 4000 mg/l, hydrogenotrophic methanogens Methanoculleus bourgensis and Methanobrevibacter sp. performed methane production via syntrophic acetate oxidation.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.