Water Microbiology & Novel Technologies

Biography

Biography: Anuradha S. Nerurkar

Abstract

Effluents of some chemical industries contain high nitrate levels which needs denitrification before discharge, otherwise it is a potential health hazard. Biological removal of nitrates from wastewater using heterotrophic denitrifying bacteria is cost effective. Biofilm denitrifying reactors are gaining importance in recent times. A significant advantage biofilm reactors afford is the control of its “bios” component. Studies carried out in this perspective are presented here. The abundance, structure and activity of the denitrifying bacteria in the sludge studied to understand their composition revealed Pseudomonas sp. and Alcaligenes sp. to be numerically high by culturable approach and betaproteobacteria by culture independent method. Comparison of denitrification showed contrasting patterns while, Diaphorobacter sp. showed accumulation of nitrite in the medium while Paracoccus sp. showed no accumulation. Bacterial biofilms shape their structure in response to environmental conditions. Higher Mg or Ca ion concentrations induced cohesion of biofilm cells in Paracoccus sp. as well as high denitrification, but contrasting biofilm architectures. Influence of carbon showed that the nitrate removal efficiency was in the order acetate > glucose > methanol > ethanol. Conditions required to enhance the growth of denitrifier with degradative capabilities is desirable in wastewater treatment processes. Different levels of nitrate did not display any significant effect on biofilm formation of Paracoccus sp. and its ability to tolerate and efficiently reduce nitrate could be said to confer a fitness payoff to the organism at high concentrations of nitrate in biofilm community.These set of studies conducted give valuable insights towards developing an efficient biofilm reactor.