Department of Chemical Engineering
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Item Biofiltration: Essentials, Research and Applications(Wiley, 2012-03) Raghuvanshi, Smita; Gupta, SureshItem Waste water treatment plant life cycle assessment: treatment process to reuse of water(Elsiever, 2017) Sangwan, Kuldip Singh; Raghuvanshi, SmitaThis paper presents a life cycle assessment (LCA) of waste water treatment plant (WWTP) in a university campus in India. Various emissions coming from the WWTP along with their impact factors are analyzed using a LCA software Umberto NXT Universal utilizing Eco-invent database v3.0. It has been found that the recycled water from the plant provides positive impact on the assessed categories. Effect of treatment system is overriding the effect of recycled water in other categories like terrestrial eco-toxicity potential, global warming potential, particulate matter formation, fossil depletion potential, etc. However, the social effect of untreated sewer and environmental effect of compost produced by the system have not been studied.Item Life Cycle Assessment of Filtration Systems of Reverse Osmosis Units: A Case Study of a University Campus(Elsiever, 2016) Sangwan, Kuldip Singh; Raghuvanshi, SmitaEnvironmental concerns are gaining importance in ground water resource management. Reverse osmosis (RO) systems are commonly used for filtration of surface and ground water for domestic and commercial purposes. This study aims to analyze the environmental impacts of electricity, fresh water and material consumption in various types of RO systems. The evaluation tool used for this study is life cycle assessment (LCA) and for this purpose Umberto NXT Universal software with Eco-invent version 3.0 database has been utilized. The inventory analysis has been done for RO systems of four different capacities, viz 25, 50, 250, and 500 liters per hour (LPH). This research also provides comparison of quantitative impacts of different capacity RO systems. All inclusive, the study presents an insight into the environmental impacts of various RO systems used in India and also discuss the alternative technologies for filtration of surface and ground water.Item Biodegradation kinetics of Cr (VI) by acclimated mixed culture(JCE, 2011-05) Raghuvanshi, Smita; Gupta, SureshChromium was discovered in 1797 by Vauquelin. Numerous industrial applications raised chromium to a very important economic element. At the same time, with the development of its uses, the adverse effects of chromium compounds in human health were being investigated. Both acute and chronic toxicity of chromium are mainly caused by hexavalent compounds. It is highly toxic in nature and causes adverse effects on human beings. The present study deals with the removal of hexavalent chromium compound from industrial waste water using biodegradation by an acclimated mixed culture developed from activated sludge. The biodegradation studies are conducted for an initial Cr(VI) concentration ranging from 10-50 mg/L. The enrichment of culture is carried out for a period of 7 days. In these experiments, 100 mL of minimum salt medium (MSM) is autoclaved and added with known amount of acclimated mixed culture obtained from the enrichment procedure. Known amount of Cr(VI) is added in autoclaved MSM to maintain the required concentration of Cr(VI). The flasks are kept in the rotary shaker which is maintained at 37 C and at 150 rpm throughout the biodegradation process. The samples are collected at different intervals. The obtained biomass growth is significant and indicate the considerable decrease in Cr(VI) concentration in the solution The biodegradation rate kinetic parameters are obtained for zero order and three and half order kinetic models.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.Item Removal of dissolved metals by Bio-remediation(RSC, 2014) Gupta, Suresh; Raghuvanshi, SmitaHeavy Metals in Water: Presence, Removal and Safety” is published by the Royal Society of Chemistry and consists of 16 independent chapters. The chapters can be broadly divided into two groups: those covering the techniques and processes used to deal with heavy metal pollution and those discussing a particular pollutant or pollution problem. The chapters are divided approximately equally between these two topics. The techniques presented include the use of modern approaches such as photocatalysis and nanotechnology (Chapters 2, 4 and 9) but by and large the volume emphasises the use of naturally occurring substances, waste products and bioremediation for removing heavy metals from water (Chapters 3, 10, 11, 14 and 15). This is understandable in light of the fact that most of the contributors come from developing countries where the emphasis for remediation is on low-cost readily accessible technologies. As a consequence the volume does not deal with heavy metal contamination resulting from high technology industries such as nuclear power, computer manufacturing and related electronics production where more technically advanced, but more expensive materials are employed in the industrially developed countries. The specific metal contamination problems presented are arsenic (Chapter 5), iron and manganese (Chapter 6), fluoride (Chapter 13) and chromium (Chapter 16), with the remaining chapters dealing with techniques and general surveys of heavy metal contamination. Chapters 7 and 8 stand out as chapters that deal with Chinese government policies on toxic metal contamination and should be very useful for foreign entrepreneurs wanting to establish new businesses in metals related industriesItem Biofiltration: Essentials, Research and Applications(Wiley, 2012-03-26) Gupta, Suresh; Raghuvanshi, Smita; Majumder, Subhajit
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