Journal Articles

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Author: search.filters.author.Srinikethan, G.

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    Laboratory studies were conducted to assess the influence of media related factors such as porosity and pore size and specific surface area on performance of up flow anaerobic biofilters (ABFs). Two simple model of 8 litres capacity up flow anaerobic biofilters (ABFs), one packed with support media granite of size 50 to 40 mm and the other packed with granite of size 25 to 20 mm were installed. The experimental anaerobic biofilters were made of PVC tubes. The hydraulic retention time (HRT) was maintained as 12 hours. The study was carried out for a period of 90 days. The waste treatment performance indicates that the biofilter associated with media of the lesser pore size and porosity with higher specific surface area demonstrated the highest BOD and COD removal 91.03% and 82.50% respectively. Copyright © Enviromedia.
    (Treatment of domestic wastewater in up flow anaerobic biofilters (using granite as packing material)) Srinikethan, G.; Shrihari, S.; Pradeepan, V.S.
    2005
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    Industrial estate planning for Mangalore Taluk in Karnataka, using remote sensing and GIS
    (2006) Navalgund, L.; Shreedhara, V.; Srinikethan, G.
    The present work presents a technique to prepare zoning atlas to classify the environment and risks involved in siting an industry. Based on risks involved in a classified zone, the best-suited industries are recommended. Mangalore city has been taken as the study area has for the present work. Sensitivity of study area has been checked in terms of air pollution, surface water pollution and groundwater pollution. The study relies upon the database procured for this purpose from Central Pollution Control Board (CPCB) and Karnataka State Remote Sensing Technology, Bang lore. The database mainly comprises of topographic maps, thematic maps and groundwater information. Buffering and over-laying of the thematic maps have been carried out as per the guidelines of CPCB. © Enviromedia Printed in India. All rights reserved.
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    Natural and anthropogenic factors controlling the dissolved organic carbon concentrations and fluxes in a large tropical river, India
    (2006) Balakrishna, K.; Kumar, I.A.; Srinikethan, G.; Mugeraya, G.
    Carbon studies in tropical rivers have gained significance since it was realized that a significant chunk of anthropogenic CO2 emitted into the atmosphere returns to the biosphere, that is eventually transported by the river and locked up in coastal sediments for a few thousand years. Carbon studies are also significant because dissolved organic carbon (DOC) is known to complex the toxic trace metals in the river and carry them in the dissolved form. For the first time, this work has made an attempt to study the variations in DOC concentrations in space and time for a period of 19 months, and estimate their fluxes in the largest peninsular Indian river, the Godavari at Rajahmundry. Anthropogenic influence on DOC concentrations possibly from the number of bathing ghats along the banks and domestic sewage discharge into the river are evident during the pre-monsoon of 2004 and 2005. The rise in DOC concentrations at the onset of monsoon could be due to the contributions from flood plains and soils from the river catchment. Spatial variations highlighted that the DOC concentrations in the river are affected more by the anthropogenic discharges in the downstream than in the upstream. The discharge weighted DOC concentrations in the Godavari river is 3-12 times lower than Ganga-Brahmaputra, Indus and major Chinese rivers. The total carbon fluxes from the Godavari into the Bay of Bengal is insignificant (0.5%) compared to the total carbon discharges by major rivers of the world into oceans. © Springer Science+Business Media, Inc. 2006.
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    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.
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    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.
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    Treatment of domestic wastewater by association of up flow anaerobic and aerobic biofilters
    (2007) Srinikethan, G.; Shrihari, S.; Pradeepan, V.S.
    Laboratory studies were conducted to assess the performance of association of up flow anaerobic & aerobic biofilters in treating domestic wastewater. Two simple models of 8 litres capacity, one up flow anaerobic biofilter (AnBF) packed with support media granite of size 20 mm and another up flow aerobic biofilter(ABF) packed with support media granite of size 10 mm respectively were installed. The experimental anaerobic & aerobic biofilters were made of PVC tubes. The hydraulic retention time (HRT) was maintained as 12 hours in anaerobic biofilter and 8 hours in aerobic biofilter. The study was carried out for a period of 90 days. The association of up flow anaerobic & aerobic biofilters demonstrated the average Turbidity, Suspended Solids, BOD and COD removal 96.56%, 96.53%, 95.67% and 90.42% respectively. The waste treatment performance indicates that the association of up flow anaerobic & aerobic biofilters is a promising technique for (sub) tropical countries. Copyright © Enviromedia.
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    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.
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    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.
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    Optimum size of granite filter media for the maximum treatment of domestic sewage in upflow anaerobic biofilters
    (2008) Srinikethan, G.; Shrihari, S.; Pradeepan, V.S.
    Laboratory studies were conducted to assess the influence of media related factors such as particle size, porosity, pore size and specific surface area on performance of upflow anaerobic biofilters (AnBFs). Three simple models of 8 litres capacity upflow anaerobic biofilters (AnBFs) packed with support media granite of size 40 mm, 20 mm and 10 mm respectively were installed. The experimental anaerobic biofilters (AnBFs) were made of PVC tubes. The hydraulic retention time (HRT) was maintained as 12 hours. The study was carried out for a period of 90 days. The waste treatment performance indicates that the anaerobic biofilter (AnBF-2) packed with granite media of moderate particle size of 20mm demonstrated the highest BOD and COD removal 91.02 % and 82.01 % respectively. Copyright © Enviromedia.