Department of Chemical Engineering
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Item Biofiltration for removal of methyl isobutyl ketone (MIBK): Experimental studies and kinetic modelling(Taylor & Francis, 2009-08-26) Raghuvanshi, SmitaThe present study deals with the biofiltration of methyl isobutyl ketone (MIBK), which is considered to be a highly toxic volatile organic compound. It is released from the paint and petrochemical industries and is one of the major contributors to air pollution. The biofiltration study was carried out on a lab scale for two months in the presence of acclimated mixed culture. The performance of the biofilter column was evaluated for different inlet loads of MIBK at air flow rates ranging from 0.18 to 0.3 m3 h−1. The maximum removal efficiency of 93% was obtained after 60 days of biofilter operation for an inlet MIBK concentration of 0.45 g m−3, and a microbial concentration of 2.36 × 108 CFU g−1 of packing material was obtained. This led to a study of shock loadings for 20 days, by varying the inlet MIBK load and air flow rate after every five days, to observe the behaviour of the biofilter column in removing sudden loads of MIBK. The biokinetic constants r max and K s were obtained using the Michaelis–Menten kinetics and were found to be 1.046 g m−3 and 0.115 g m−3 h−1, respectively, with a coefficient of determination (R 2) of 0.993. The obtained experimental results were validated with the Ottengraf and Van den Oever kinetic model. The critical inlet concentration, critical inlet load and biofilm thickness were also estimated using the results obtained from the model predictions.Item Biodegradation kinetics of methyl iso-butyl ketone by acclimated mixed culture(Elsiever, 2009-06-26) Raghuvanshi, SmitaMethyl iso-butyl ketone (MIBK) is a widely used volatile organic compound (VOC) which is highly toxic in nature and has significant adverse effects on human beings. The present study deals with the removal of MIBK using biodegradation by an acclimated mixed culture developed from activated sludge. The biodegradation of MIBK is studied for an initial MIBK concentration ranging from 200–700 mg l−1 in a batch mode of operation. The maximum specific growth rate achieved is 0.128 h−1 at 600 mg l−1of initial MIBK concentration. The kinetic parameters are estimated using five growth kinetic models for biodegradation of organic compounds available in the literature. The experimental data found to fit well with the Luong model (R 2 = 0.904) as compared to Haldane model (R 2 = 0.702) and Edward model (R 2 = 0.786). The coefficient of determination (R 2) obtained for the other two models, Monod and Powell models are 0.497 and 0.533, respectively. The biodegradation rate found to follow the three-half-order kinetics and the resulting kinetic parameters are reported.Item Experimental studies and kinetic modeling for removal of methyl ethyl ketone using biofiltration(Elsiever, 2009-09) Raghuvanshi, SmitaThe removal of toxic methyl ethyl ketone (MEK) is studied in a lab scale biofilter packed with mixture of coal and matured compost. The biofiltration operation is divided into 5 phases for a period of 60 days followed by shock loading conditions for three weeks. The maximum removal efficiency of 95% is achieved during phase II for an inlet concentration of 0.59 g m−3, and 82–91% for the inlet concentration in the range of 0.45–1.23 g m−3 of MEK during shock loads. The Michaelis–Menten kinetic constants obtained are 0.086 g m−3 h−1 and 0.577 g m−3. The obtained experimental results are validated using Ottengraf–van den Oever model for zero-order diffusion-controlled region to understand the mechanism of biofiltration. The critical inlet concentration of MEK, critical inlet load of MEK and biofilm thickness are estimated using the results obtained from model predictions.Item Simulation Studies on Transient Model for Biofilter operated in Periodic Mode(JET, 2006) Raghuvanshi, SmitaBiofiltration of off-gases containing Volatile Organic Compounds (VOCs) is a reliable and cost effective technology for VOCs removal. Due to many inherent advantages, most of the industries operate biofilters under the periodic conditions (highly transient). Taking the importance of such operation into account, a model is developed based on the transient conditions. In this study, a Linear Driving Force (LDF) model is used, which takes into account both mechanisms (adsorption and biodegradation) involved in biofiltration process. The rate equation is given by the modified three-parameter Monod-type expression. The results obtained from the present model are validated with the experimental data and the results obtained from earlier model reported in the literature. The simulations are also carried out to understand the influence of various important parameters such as inlet VOCs concentrations, bed height and gas velocity on the biofiltration process operated in the periodic mode.