Indrani Khan | Indian Institute of Engineering Science and Technology, Shibpur (original) (raw)

Papers by Indrani Khan

Identification of tree species that can biologically monitor air pollution and can endure air pol... more Identification of tree species that can biologically monitor air pollution and can endure air pollution is very much important for a sustainable green belt development around any polluted place. To ascertain the species, ten tree species were selected on the basis of some previous study from the campus of the University of Burdwan and were studied in the pre-monsoon and post-monsoon seasons. The study has been designed to investigate biochemical and physiological activities of selected tree species as the campus is presently exposed to primary air pollutants and their impacts on plant community were observed through the changes in several physical and biochemical constituents of plant leaves. As the plant species continuously exchange different gaseous pollutants in and out of the foliar system and are very sensitive to gaseous pollutants, they serve as bioindicators. Due to air pollution, foliar surface undergoes different structural and functional changes. In the selected plant species, it was observed that the concentration of primary air pollutants, proline content, pH, relative water holding capacity, photosynthetic rate, and respiration rate were higher in the pre-monsoon than the post-monsoon season, whereas the total chlorophyll, ascorbic acid, sugar, and conductivity were higher in the post-monsoon season. From the entire study, it was observed that the concentration of sulfur oxide (SO x), nitrogen oxide (NO x), and suspended particulate matter (SPM) all are reduced in the post-monsoon season than the pre-monsoon season. In the pre-monsoon season, SO x , NO x , and SPM do not have any significant correlation with biochemical as well as physiological parameters. SPM shows a negative relationship with chlorophyll 'a' (r = −0.288), chlorophyll 'b' (r = −0.267), and total chlorophyll (r = −0.238). Similarly, chlorophyll a, chlorophyll b, and the total chlorophyll show negative relations with SO x and NO x (p < 0.005) during the post-monsoon season. Proline shows a positive relationship with SO x in the pre-monsoon season whereas in the post-monsoon season proline content shows a positive relationship with both SO x and NO x. The present study facilitates to screen eight sensitive and two moderately tolerant tree species according to their air pollution tolerance index (APTI) values.

Natural coagulants have been the focal research by many investigators through the last decade owi... more Natural coagulants have been the focal research by many investigators through the last decade owing to the problems
caused by the chemical coagulants. Optimization of process parameters is vital for the effectiveness of coagulation process.
In the present study optimization of parameters like pH, dose of coagulant and mixing speed were studied using natural
coagulant chitin. Jar test apparatus was used to perform the coagulation. The results showed that the removal of turbidity
was up to 99% by both alum and chitin at lower doses of coagulant i.e 0.1 – 0.3g/L. The optimum conditions observed for
alum and chitin were pH – 7, all pH ranges, coagulant dose – 0.1 – 0.4g/ L, 0.1 – 0.3g/L and mixing speed – rapid mixing at
100rpm for 10min and slow mixing 20rpm for 20 minutes. Hence it can be concluded that chitin can be used for treating
water even with large seasonal variation in turbidity.