Faculty Publications
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Item Characterization of heat transfer of large orbitally shaken cylindrical bioreactors(Elsevier, 2014) Raval, K.; Kato, Y.; Büchs, J.Disposable shaking bioreactors are a promising alternative to other disposable bioreactors owing to their ease of operation, flexibility, defined hydrodynamics and characterization. Shaken bioreactors of sizes 20. L and 50. L are characterized in terms of heat transfer characteristics in this research work. Water and an 80% glycerol-water system were used as fluid. Results indicated large heat generation due to shake mixing which was observed by temperature difference between the fluid inside the vessel and the surrounding air outside the vessel. Maximum temperature difference of ca. 30. K was encountered for a 50. L vessel, at 300. rpm and 20. L filling volume. Outside heat transfer rate was governing the overall heat transfer process. Lateral air flow did increase heat transfer rates to large extent. An empirical correlation of overall heat transfer coefficient was obtained in terms of filling volume, rotational speed and lateral air flow rate. However, as the vessel thickness increased, the overall heat transfer process was limited by vessel wall resistance. © 2014 Elsevier B.V.Item Enhanced degradation of azo dye using mixed cultures of white-rot fungi in a modified rotating packed disc bioreactor and reuse of treated water(Elsevier Ltd, 2023) Kalnake, R.P.; Raval, R.; Murthy, D.V.R.; Vanzara, P.B.; Raval, K.Reactive azo dyes are toxic and carcinogenic. In this study, mixed cultures of white-rot fungi (WRF) are used to treat synthetic reactive black 5 (RB-5) wastewater in a modified rotating packed disc bioreactor (RPDB). The continuous degradation studies were carried out for 25 days under the influence of the recycle stream in which 3665 L of synthetic effluent was treated. The dye wastewater was completely decolorized with more than 93 % chemical oxygen demand (COD) reduction using the mixed fungal culture. During the continuous operation, the COD of influent reduced more than 85 % for successive 25 days of continuous operation at hydraulic retention time of 10.8 h. The dry biomass loading was about 0.14 g/g GAC at the end of the continuous process. The rate of COD removal followed first order kinetics with a rate constant of 0.026 per hour. The treated water was reused to produce melanin from microbial culture. © 2023 Elsevier Ltd