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Presence of industrial dyes and heavy metal as a contaminant in environment poses a great risk to human health. In order to develop a potential technology for remediation of dyes (Reactive remazol red, Yellow 3RS, Indanthrene blue and Vat novatic grey) and heavy metal [Cu(II), Ni(II), Cd(II), Zn(II), Cr(VI) and Pb(II)] contamination, present study was performed with entomopathogenic fungi, Beauveria bassiana (MTCC no. 4580). High dye removal (88-97%) was observed during the growth of B. bassiana while removal percentage for heavy metals ranged from 58 to 75%. Further, detailed investigations were performed with Pb(II) in terms of growth kinetics, effect of process parameters and mechanism of removal. Growth rate decreased from 0.118 h (control) to 0.031 h, showing 28% reduction in biomass at 30 mg L Pb(II) with 58.4% metal removal. Maximum Pb(II) removal was observed at 30 °C, neutral pH and 30 mg L initial metal concentration. FTIR analysis indicated the changes induced by Pb(II) in functional groups on biomass surface. Further, microscopic analysis (SEM and atomic force microscopy (AFM)) was performed to understand the changes in cell surface morphology of the fungal cell. SEM micrograph showed a clear deformation of fungal hyphae, whereas AFM studies proved the increase in surface roughness (RSM) in comparison to control cell. Homogenous bioaccumulation of Pb(II) inside the fungal cell was clearly depicted by TEM-high-angle annular dark field coupled with EDX. Present study provides an insight into the mechanism of Pb(II) bioremediation and strengthens the significance of using entomopathogenic fungus such as B. bassiana for metal and dye removal.

Afly ash membrane developed by The Energy and Resources Institute (TERI), New Delhi was studied for its applicability in municipal wastewater treatment. In particular, the effect of aeration on preventing membrane fouling was studied. The velocity field generated by aeration was studied to understand how the rising bubbles would efficiently scour the membrane filter and prevent fouling. Particle image velocimetry was used to monitor the air bubble movement along the membrane surface. The optimal reactor configuration (membrane module orientation) for which the aeration would impart maximum shear over the membrane was determined using potable water. This reactor configuration was later used for the biological treatment of synthetic wastewater. The second aspect of the study involved designing a support system to improve the strength of the membrane. Membrane modules without any internal support were able to withstand trans-membrane pressures (TMP) up to 270 mmHg. Two types of frames/seperators were used to increase membrane strength. In one type of the frame, support was unidirectional and in another, bidirectional. Bidirectionallysupported membranes were able to withstanda TMP of 760mmHg for a period of 7 days. At a constant filtration rate, a membrane bioreactor with more than one membrane in parallel operation was able to delay the fouling process than in a single membrane system due to lesser pressure across the membranes. As expected, membrane fouling took longer time in the systems operated at higher air flowrate due to better scouring action of the air bubbles.

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