1 23 Clean Technologies and Environmental Policy Focusing on Technology Research, Innovation, Demonstration, Insights and Policy Issues for Sustainable Technologies ISSN 1618-954X Clean Techn Environ Policy DOI 10.1007/s10098-013-0621-7 Removal of nitrate and COD from wastewater using denitrification process: kinetic, optimization, and statistical studies Sanak Ray, Ayusman Mohanty, S. S. Mohanty, Snehasish Mishra & G. Roy Chaudhury