Faculty Publications

Permanent URI for this communityhttps://idr.nitk.ac.in/handle/123456789/18736

Publications by NITK Faculty

Browse

Author: search.filters.author.Shetty K, K.V.Subject: search.filters.subject.Bioreactors

Search Results

Now showing 1 - 7 of 7
  • No Thumbnail Available
    Item
    Performance of pulsed plate bioreactor for biodegradation of phenol
    (2007) Shetty K, K.V.; Kalifathulla, I.; Srinikethan, G.
    Biodegradation of phenol was carried out using Nocardia hydrocarbonoxydans immobilised on glass beads, in a pulsed plate bioreactor. The effect of operating parameters like frequency of pulsation and amplitude of pulsation on the performance of pulsed plate bioreactor for biodegradation of phenol in a synthetic wastewater containing 500 ppm phenol was studied. Axial concentration profile measurements revealed that the pulsed plate bioreactor shows continuous stirred tank behaviour. As the amplitude was increased, percentage degradation increased, reaching 100% at amplitude of 4.7 cm and higher. Introduction of pulsation is found to increase the percentage degradation. Percentage degradation has increased with increase in frequency and 100% degradation was achieved at 0.5 s-1 and above. Biofilms developed in a non-pulsed bioreactor were thicker than those in the pulsed plate bioreactor. But biofilm thickness remained almost constant with increasing frequency. Biofilm density was found to be influenced by pulsation. The time required to reach steady state was more for pulsed reactor than the non-pulsed reactor and this start-up time had increased with increase in frequency of pulsation. The performance studies reveal that the pulsed plate bioreactor with immobilized cells has the potential to be an efficient bioreactor for wastewater treatment. © 2006 Elsevier B.V. All rights reserved.
  • No Thumbnail Available
    Item
    Biological phenol removal using immobilized cells in a pulsed plate bioreactor: Effect of dilution rate and influent phenol concentration
    (2007) Shetty K, K.V.; Ramanjaneyulu, R.; Srinikethan, G.
    The continuous aerobic biodegradation of phenol in synthetic wastewater was carried out using Nocardia hydrocarbonoxydans immobilized over glass beads packed between the plates in a pulsed plate bioreactor at a frequency of pulsation of 0.5 s-1 and amplitude of 4.7 cm. The influence of dilution rate and influent phenol concentration on start up and steady state performance of the bioreactor was studied. The time taken to reach steady state has increased with increase in dilution rate and influent phenol concentration. It was found that, as the dilution rate is increased, the percentage degradation has decreased. Steady state percentage degradation was also reduced with increased influent phenol concentration. Almost 100% degradation of 300 and 500 ppm influent phenol could be achieved at a dilution rate of 0.4094 h-1 and more than 99% degradation could be achieved with higher dilution rates. At a higher dilution rate of 1.0235 h-1 and at concentrations of 800 and 900 ppm the percentage degradation has reduced to around 94% and 93%, respectively. The attached biomass dry weight, biofilm thickness and biofilm density at steady state were influenced by influent phenol concentration and dilution rate. © 2007 Elsevier B.V. All rights reserved.
  • No Thumbnail Available
    Item
    Artificial neural networks model for the prediction of steady state phenol biodegradation in a pulsed plate bioreactor
    (2008) Shetty K, K.V.; Nandennavar, S.; Srinikethan, G.
    Background: A recent innovation in fixed film bioreactors is the pulsed plate bioreactor (PPBR) with immobilized cells. The successful development of a theoretical model for this reactor relies on the knowledge of several parameters, which may vary with the process conditions. It may also be a time-consuming and costly task because of their nonlinear nature. Artificial neural networks (ANN) offer the potential of a generic approach to the modeling of nonlinear systems. Results: A feedforward ANN based model for the prediction of steady state percentage degradation of phenol in a PPBR by immobilized cells of Nocardia hydrocarbonoxydans (NCIM 2386) during continuous biodegradation has been developed to correlate the steady state percentage degradation with the flow rate, influent phenol concentration and vibrational velocity (amplitude x frequency). The model used two hidden layers and 53 parameters (weights and biases). The network model was then compared with a Multiple Regression Analysis (MRA) model, derived from the same training data. Further these two models were used to predict the percentage degradation of phenol for blind test data. Conclusions: The performance of the ANN model was superior to that of the MRA model and was found to be an efficient data-driven tool to predict the performance of a PPBR for phenol biodegradation. © 2008 Society of Chemical Industry.
  • No Thumbnail Available
    Item
    Combined effect of plate pulsation parameters and phenol concentrations on the phenol removal efficiency of a pulsed plate bioreactor with immobilized cells
    (2008) Shetty K, K.V.; Kedargol, M.R.; Srinikethan, G.
    Continuous aerobic biodegradation of phenol in synthetic wastewater with phenol at different concentrations (200, 300, 500, 800 and 900 ppm) was carried out in a pulsed plate column, which is used as a bioreactor with immobilised cells of Nocardia hydrocarbonoxydans (NCIM 2386) at a dilution rate of 0.4094 h-1 and amplitude of 4.7 cm at various frequencies of pulsation (0, 0.25, 0.5, 0.75 and 1 s-1). The effect of frequency of pulsation on the steady state performance of the bioreactor for phenol biodegradation at different influent concentrations was studied. Percentage degradations were observed to be a combined effect of volumetric phenol loading, reactor residence time, mass transfer limitations and phenol inhibition effect. At 500 ppm influent phenol concentration the effect of frequencies of pulsation on the steady state percentage degradation at different amplitudes was studied. The percentage degradation increased with increase in frequency and almost 100% degradation was achieved at 0.75s-1, 0.5s-1 or 0.25s -1, with 3.3, 4.7 or 6.0 cm amplitudes respectively and hence the vibrational velocity (amplitude * frequency) was found to influence the steady state performance of the reactor. It was found that optimum vibrational velocities need to be fixed for maximum removal efficiency of the bioreactor depending on the influent phenol concentration. © IWA publishing 2008.
  • No Thumbnail Available
    Item
    Oxygen mass transfer coefficients in a three-phase pulsed plate bioreactor
    (Berkeley Electronic Press, 2010) Shetty K, K.V.; Srinikethan, G.
    Volumetric oxygen mass transfer coefficient is a decisive parameter for the selection of any contactor as an aerobic bioreactor. A pulsed plate column with fixed bed of solids in interplate spaces is a recent innovation in the field of immobilized cell bioreactors. Volumetric oxygen mass transfer coefficients are determined in a three-phase pulsed plate column involving air and water phases and with a fixed bed of glass particles, which can serve as a surface for cell immobilization packed in the interplate spaces. The volumetric mass transfer coefficients obtained in this column range from 0.067 to 0.1495 s-1la with these variables was developed. The volumetric oxygen mass transfer coefficient values in the three-phase pulsed plate column are found to be similar or higher than the literature reported values for conventional two-phase pulsed plate columns. The values of volumetric oxygen mass transfer coefficients in the three-phase pulsed plate column are of higher order of magnitude than the literature reported values of volumetric oxygen mass transfer coefficient for many other three-phase gas-liquid-solid reactors. The pulsed plate column with fixed bed of solids is proven to have all the potential to be used as an aerobic bioreactor with immobilized cells due to its better gas-liquid mass transfer characteristics. Copyright © 2010 The Berkeley Electronic Press. All rights reserved.
  • No Thumbnail Available
    Item
    Shear stress effects on production of exopolymeric substances and biofilm characteristics during phenol biodegradation by immobilized Pseudomonas desmolyticum (NCIM2112) cells in a pulsed plate bioreactor
    (Taylor and Francis Inc. 325 Chestnut St, Suite 800 Philadelphia PA 19106, 2016) Veena, B.R.; Shetty K, K.V.; Saidutta, M.B.
    This article reports studies on a continuous pulsed plate bioreactor (PPBR) with the cells of Pseudomonas desmolyticum (NCIM2112) immobilized on granular activated carbon (GAC) used as a biofilm reactor for biodegradation of phenol. Almost complete removal of 200 ppm phenol could be achieved in this bioreactor. Biofilm structure and characteristics are influenced by hydrodynamic and shear conditions in bioreactors. In this article, the effect of shear stress induced by frequency of pulsation on biofilm characteristics during the startup period in the PPBR is reported. The startup time decreased with the increase in frequency of pulsation. The formation of biofilm in PPBR was found to have three phases: accumulation, compaction, and plateau. The effect of frequency on production of exoploymeric substances (EPS) such as, protein, carbohydrate, and humic substance is reported. An increase in shear stress induced by the frequency of pulsation increased the production of exopolymeric substances in the biofilm during startup of the bioreactor. Increase in shear stress caused a decrease in biofilm thickness and an increase in dry density of the biofilm. Increase in shear stress resulted in a smoother and thinner biofilm surface with more compact and dense structure. © 2016, Copyright © Taylor & Francis Group, LLC.
  • No Thumbnail Available
    Item
    Effect of dilution rate on dynamic and steady-state biofilm characteristics during phenol biodegradation by immobilized Pseudomonas desmolyticum cells in a pulsed plate bioreactor
    (Higher Education Press, 2016) Rangappa, V.B.; Shetty K, K.V.; Bharthaiyengar, S.M.
    Pulsed plate bioreactor (PPBR) is a biofilm reactor which has been proven to be very efficient in phenol biodegradation. The present paper reports the studies on the effect of dilution rate on the physical, chemical and morphological characteristics of biofilms formed by the cells of Pseudomonas desmolyticum on granular activated carbon (GAC) in PPBR during biodegradation of phenol. The percentage degradation of phenol decreased from 99% to 73% with an increase in dilution rate from 0.33 h–1 to 0.99 h–1 showing that residence time in the reactor governs the phenol removal efficiency rather than the external mass transfer limitations. Lower dilution rates favor higher production of biomass, extracellular polymeric substances (EPS) as well as the protein, carbohydrate and humic substances content of EPS. Increase in dilution rate leads to decrease in biofilm thickness, biofilm dry density, and attached dry biomass, transforming the biofilm from dense, smooth compact structure to a rough and patchy structure. Thus, the performance of PPBR in terms of dynamic and steady-state biofilm characteristics associated with phenol biodegradation is a strong function of dilution rate. Operation of PPBR at lower dilution rates is recommended for continuous biological treatment of wastewaters for phenol removal. [Figure not available: see fulltext.] © 2016, Higher Education Press and Springer-Verlag Berlin Heidelberg.