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 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 Continuous phenol removal using Nocardia hydrocarbonoxydans in spouted bed contactor: Shock load study(2009) Dabhade, M.A.; Saidutta, M.B.; Murthy, D.V.R.Shock load studies are essential to investigate the suitability of biocontactors in degradation of pollutants. In the present work, the degradation of phenol by immobilized Nocardia hydrocarbonoxydans in a spouted bed contactor was conducted. Granular activated carbon (GAC) and polymer beads were tested for the immobilization of cells of N. hydrocarbonoxydans-NCIM 2386. Initially, batch immobilization study was conducted to know the quantity of immobilized microorganisms per gram of solids and then the immobilized solids were used in the spouted bed contactor for phenol degradation. Also, the shock loading of phenol and hydraulic shock load test was performed to check the stability of operation. The immobilized Nocardia cells sustained the shock load and hydraulic load of phenol. Increase of influent phenol concentration and dilution rates increased the steady state effluent phenol concentration. Almost 95% degradation at maximum phenol loading of 0.73 gL-1h-1 was achieved. GAC has more attached biomass weight compared to polymer beads. © 2009 Academic Journals.Item Separation of dimethyl phenol using a spiral-wound RO membrane - Experimental and parameter estimation studies(2009) Srinivasan, G.; Sundaramoorthy, S.; Murthy, D.V.R.Reverse osmosis (RO) is increasingly used as a separation technique in chemical and environmental engineering for the removal of organics and organic pollutants present in waste water. Treatment of organics by RO is dependent on many factors and hence developing a viable RO system involves extensive pilot-plant studies. The removal of an organic compound, namely dimethyl phenol, using a polyamide membrane was investigated in this study. Experiments were conducted on a laboratory-scale spiral-wound RO module. The permeate concentrations and rejection coefficient values were measured for various transmembrane pressures and feed concentrations. A maximum rejection of 97% was observed. A mathematical model was developed for the RO module assuming a solution-diffusion mechanism for solute and solvent transport through the membrane and considering the concentration and pressure to be uniform on both permeate and retentate sides. The model has four parameters. A graphical method for estimating the model parameters was proposed. The model and the estimated parameter values were validated with the experimental data. The model was able to predict the permeate concentration within an error of 19% and rejection within 2% error. © 2009.Item An optimization study on microwave irradiated, decomposition of phenol in the presence of H2O2(2009) Prasannakumar, B.R.; Iyyaswami, I.; Murugesan, T.Background: Removal of phenol from industrial waste waters involves basic techniques namely extraction, biodegradation, photocatalytic degradation, etc. Among the available processes, the oxidation of phenols using H2O2 is a suitable alternative because of low cost and high oxidizing power. The application of an oxidation process for the decomposition of stable organic compounds in waste water leads to the total degradation of the compounds rather than transferring from one form to another. Since oxidation using Fenton's reagent ismore dependent on pH, in this present work it was proposed to use H2O2 coupled with microwave irradiation. The effects of initial phenol concentration, microwave power and the irradiation time on the amount of decomposition were studied. Results: In the present work experiments were conducted to estimate the percentage degradation of phenol for different initial concentrations of phenol (100, 200, 300, 400 and 500 mg L-1), microwave power input (180, 360, 540, 720 and 900 W) for different irradiation times. The kinetics of the degradation process were examined through experimental data and the decomposition rate follows first-order kinetics. Response surface methodology (RSM) was employed to optimize the design parameters for the present process. The interaction effect between the variables and the effect of interaction on to the responses (percentage decomposition of phenol) of the process was analysed and discussed in detail. The optimum values for the design parameters of the process were evaluated (initial phenol concentration 300 mg L-1, microwave power output 668 W, and microwave irradiation time 60 s, giving phenol degradation 82.39%) through RSM by differential approximation, and were confirmed by experiment. Conclusion: The decomposition of phenol was carried out using H2O2 coupled with microwave irradiation for different initial phenol concentrations, microwave power input and irradiation times. The phenol degradation process follows first-order kinetics. Optimization of the process was carried out through RSM by forming a design matrix using CCD. The optimized conditions were validated using experiments. The information is of value for the scale up of the oxidation process for the removal of phenol from wastewater. © 2008 Society of Chemical Industry.Item Adsorption of phenol on granular activated carbon from nutrient medium: Equilibrium and kinetic Study(2009) Dabhade, M.A.; Saidutta, M.B.; Murthy, D.V.R.This paper presents the adsorption of phenol on granular activated carbon (GAC) from nutrient medium suitable for microorganisms' growth and also the subsequent biodegradation. Two parameter Langmuir and Freundlich adsorption isotherm models were studied using large range of phenol concentration (50-1000 mg/L). In low range of phenol concentration (50-300 mg/L), correlation coefficient, normalized deviation "g% and separation factor were 0.9989,2.18% and 0.38-0.78 respectively, while for higher concentration range (400-1000 mg/L), the corresponding values were 0.9719, 1.9% and 0.45- 0.67. Freundlich isotherm gave correlation coefficient of 0.9984, 1/n. value of 0.7269 and normalized deviation of 4.55%. Comparison based on R2, adjusted R2, normalized deviation and root mean square deviation (RMSD) showed that the Redke-Prausnitz isotherm model gives better prediction compared to other models. Adsorption of phenol follows pseudo second order kinetics with correlation coefficient closer to one. Biodegradation study using immobilized cells of Nocardia hydrocarbonoxydans on GAC showed that, biodegradation begins well before GAC reaches the saturation period.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 Validation of an analytical model for spiral wound reverse osmosis membrane module using experimental data on the removal of dimethylphenol(2011) Srinivasan, G.; Sundaramoorthy, S.; Murthy, D.V.R.A new analytical model for spiral wound RO module has been recently proposed by Sundaramoorthy et al. [1] and the same has been validated [2] with experimental data obtained on a laboratory scale RO unit used for the removal of chlorophenol. In this paper, the need to check the validity of this model with solutes other than chlorophenol is addressed by conducting suitable experiments with dimethylphenol as solute and validating this experimental data with the model. The four model parameters namely solvent transport coefficient Aw, solute transport coefficient Bs, feed channel friction parameter b and the mass transfer coefficient k were estimated. The results show that the mass transfer coefficient is influenced not only by fluid velocity but also by the solvent flux and solute concentration. A new correlation for mass transfer coefficient k, proposed by Sundaramoorthy et al. [2] for experimental data taken with chlorophenol as solute is also shown to be consistent with the experimental readings recorded in this study taking dimethylphenol as solute. Comparison of model predictions with the experimental observations demonstrated the capability of the model in predicting permeate concentration within 12% error, retentate flow within 5% error and rejection coefficient within 2% error. © 2011 Elsevier B.V.