Browsing by Author "Brahma D. Tripathi"

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Dynamics of traffic noise in a tropical city Varanasi and its abatement through vegetation
(2008) Vinita Pathak; Brahma D. Tripathi; Virendra Kumar Mishra
Noise level monitoring and its reduction with different width and height of vegetation belt were studied in the Varanasi city. Noise level monitoring of the Varanasi city revealed the fact that area category A (without vegetation) was highly polluted as compare to area category B (with vegetation) having less fluctuation of traffic load. Four plant species Putranjeva roxburghi, Cestrum nocturnum, Hibiscus rosasinensis and Murraya peniculata were tested for noise reduction study at different frequencies. Experiment revealed the fact that H. rosasinensis reduced noise highest at both low and high frequencies (100-500 Hz, 22 dB and 2.5-6.3 KHz 26 dB), followed by M. peniculata (100-500 Hz, 18 dB and 2.5-6.3 KHz 20 dB), P. roxburghi (100-500 Hz 15 dB and 2.5-6.3 KHz 17 dB) and C. nocturnum (100-500 Hz 9 dB and 2.5-6.3 KHz 14 dB). Significance of vegetation belt in noise reduction was established with multiple regression models. © Springer Science+Business Media B.V. 2007.
Nitrogen and Phosphorus Removal-capacity of Four Chosen Aquatic Macrophytes in Tropical Freshwater Ponds
(1991) Brahma D. Tripathi; Jaya Srivastava; Kiran Misra
The nutrient removal-capacity of four chosen aquatic macrophytes was tested in both natural and laboratory conditions. Laboratory experiments were performed under controlled conditions using ‘microcosm’ methods wherein the plants were grown in three different nutrient concentrations. For field experiments, three ponds were selected that had different levels of plant nutrient concentrations and accordingly were treated as polluted, moderately polluted, and relatively unpolluted, respectively, the object being to study the nutrient removal-capacity of chosen aquatic macrophytes living in ‘natural’ conditions. For the present investigation, four common and widespread aquatic plants growing in all three ponds were chosen: Water-hyacinth (Eichhornia crassipes [Mart.] Solms), Water-lettuce (Pistia stratiotes L.), Round-leafed Water-fern (Salvinia rotundifolia Willd.), and Lesser Duckweed (Lemna minor L.). These plants were selected also because of their frequent presence in aquatic bodies in the region and their high reproductive capacity. From the results it is revealed that, during the summer and rainy seasons, the highest content of nitrogen was removed by the Eichhornia, followed by the Pistia > Lemna > Salvinia, while during winter the highest content of nitrogen was removed by the Eichhornia followed by the Lemna > Pistia > Salvinia. Higher phosphorus removal was found in summer than in the rainy or the winter season. Phosphorus removal by the macrophytes was in the order of the Eichhornia > Pistia > Lemna > Salvinia, during the summer and rainy seasons, whereas the highest content of phosphorus was removed by Lemna in the winter months. The nutrient removal-capacity was rated to be highest by the Water-hyacinth, followed by the Pistia, then the Lemna, and lowest by the Salvinia. It was also evident that the nutrient removal increased with increasing nutrient concentration in the wastewater. The removal of nitrate by the selected macrophytes ranged from 42.0% to 96.2%, while phosphate removal ranged from 36.3% to 70.2%. A positive and significant correlation was obtained between the concentration of nitrate and phosphate in the waters and plant tissues that were studied, and it is thought that a useful strategy to employ might be to grow the Eichhornia and the Lemna together at least where winter temperatures were likely to be low enough to favour the Lemna at that season, though at other times it is apt to be a nuisance. © 1991, Foundation for Environmental Conservation. All rights reserved.
Utilization of fly ash in adsorption of heavy metals from wastewater
(2008) Archana Mishra; Brahma D. Tripathi
The aim of this study was to assess the toxicity reduction of wastewaster after treatment with fly ash. Fly ash is a waste material which is formed as a result of coal burning in power plants, but has the potential to adsorb heavy metal ions. The present study examined the adsorption capacity of fly ash to adsorb Pb2+, Cu2+, and Zn2+ from waste water under different conditions of contact time, pH, and temperature. Uptake of metal ions by fly ash generally rose with increasing pH. At lower temperatures the uptake of heavy metal adsorption were enhanced. Significant reduction in Pb2+ (79%), Cu2+ (53%), and Zn2+ (80%) content was found after treatment with fly ash of waste water treatment. Using the microtox test toxicity of the effluent was reduced by 75% due to removal of Pb2+ ion by the fly ash. Data indicated that fly ash generated by power plants may be used beneficially to remove metals from waste water. © 2008 Taylor & Francis.