Faculty Publications
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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.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.Item Effect of media characteristics on performance of upflow aerobic biofilters(2008) Srinikethan, G.; Shrihari, S.; Pradeepan, V.S.Laboratory studies were conducted to assess the influence of media related factors such as porosity, pore size, particle size and specific surface area on the performance of upflow aerobic biofilters (ABFs). Three simple models of 8 litre capacity upflow submerged ABFs packed with support media of size 40 mm, 20 mm and 10 mm respectively were installed. The hydraulic retention time (HRT) was maintained as 12 hours. The study was carried out for a period of 90 days. The reactor performance indicated that the aerobic biofilter (ABF-3), associated with media of lowest porosity, pore size, particle size and highest specific surface area, demonstrating the highest BOD and COD removal efficiency of 93.32 % and 85.01 % respectively.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.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.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.Item Modelling and simulation of steady-state phenol degradation in a pulsed plate bioreactor with immobilised cells of Nocardia hydrocarbonoxydans(2011) Shetty K, V.S.; Verma, D.K.; Srinikethan, G.A novel bioreactor called pulsed plate bioreactor (PPBR) with cell immobilised glass particles in the interplate spaces was used for continuous aerobic biodegradation of phenol present in wastewater. A mathematical model consisting of mass balance equations and accounting for simultaneous external film mass transfer, internal diffusion and reaction is presented to describe the steady-state degradation of phenol by Nocardia hydrocarbonoxydans (Nch.) in this bioreactor. The growth of Nch. on phenol was found to follow Haldane substrate inhibition model. The biokinetic parameters at a temperature of 30 ± 1 °C and pH at 7.0 ± 0.1 are ? m = 0.5397 h -1, K S = 6.445 mg/L and K I = 855.7 mg/L. The mathematical model was able to predict the reactor performance, with a maximum error of 2% between the predicted and experimental percentage degradations of phenol. The biofilm internal diffusion rate was found to be the slowest step in biodegradation of phenol in a PPBR. © 2010 Springer-Verlag.Item Mixing and solid-liquid mass transfer characteristics in a three phase pulsed plate column with packed bed of solids in interplate spaces-a novel aerobic immobilized cell bioreactor(2011) Shetty K, V.S.; Srinikethan, G.Background: The pulsed plate column (PPC) with packed bed of solids in the interplate spaces finds use as a three phase aerobic bioreactor and is a potential heterogeneous catalytic reactor. Good knowledge of the extent of mixing in the liquid phase and solid-liquid mass transfer coefficient are essential for modeling, design and optimization of these columns. The present work aims at the study of liquid phase mixing and solid-liquid mass transfer characteristics in a three phase PPC. Results: Residence time distribution studies were performed. Dispersion number was found to increase with increase in liquid superficial velocities, frequency of pulsation, amplitude of pulsation and the vibrational velocities. Increase in frequency and amplitude of pulsation, and hence increase in vibrational velocity, resulted in increase of the solid-liquid mass transfer coefficient. Conclusions: The mixing behaviour in this contactor approximated a mixed flow behaviour. The three phase PPC was found to outperform many other kinds of three phase contactors in terms of solid liquid mass transfer characteristics. Empirical correlations developed can be used for the determination of solid-liquid mass transfer coefficients for three phase PPC and hence can facilitate the design, scale-up and modeling of these columns, when used as chemical or biochemical reactors. © 2011 Society of Chemical Industry.Item Biodegradation of phenol using immobilized nocardia hydrocarbonoxydans in a pulsed plate bioreactor: Effect of packed stages, cell carrier loading, and cell acclimatization on startup and steady-state behavior(2013) Shetty K, K.; Yarangali, S.B.; Srinikethan, G.The effect of the number of stages and cell carrier loading on the steady-state and startup performance of a continuous pulsed plate bioreactor with glass beads as the cell carrier material for biodegradation of phenol in wastewater using immobilized Nocardia hydrocarbonoxydans has been studied. It was found that the performance of the pulsed plate bioreactor during startup and at steady state can be improved by an increase in cell carrier loading, number of stages, total plate stack height, and with a decrease in plate spacing. The startup time for the continuous bioreactor can be decreased by increasing the number of preacclimatization steps for the cells. The attainment of steady effluent phenol concentration can be considered as an indication of steady state of the continuous bioreactor, as when phenol concentration attained a steady value, biofilm thickness, and the attached biomass dry weight also attained a constant value. © 2013 Copyright Taylor and Francis Group, LLC.