Removal of TNT and its Biotransformation Products under Sequential Anaerobic/Denitrifying Conditions

Han, Gee-Bong; Clarkson, William W.

Environmental Engineering Research 1996;1(1): 73-79.

¹National Institute of Environmental Research, 613-2 Bulkwang-dong, Seoul, Korea
²School of Environmental and Civil Engineering, Oklahoma State University, Engineering South 207, Stillwater, Oklahoma 74078

Corresponding Author: Gee-Bong Han ,

ABSTRACT

A selected nitroaromatic compound at an initial concentration of 100mg TNT/L was trans formed into intermediate transformation products by anaerobic microbial activity. The products of TNT biotransformation accumulated transiently in the anaerobic medium, and certain intermediates showed no fur ther degradation toward mineralization. The medium, including products, was transferred into other reactors containing nitrated and denitrifying microbial cultures. The results showed disappearance of accumulated inter¬mediate products during 6 days of extended incubation time. This suggested that complete TNT biodegradation could be achieved through the consecutive two-stage anaerobic/anoxic redox sequence. To test nonbiological ef fects on intermediate compounds by extracellular material, cell-free filtrates were tested but no activity on TNT was observed in the absence of active microbial cultures. Sulfide inhibition to denitrification was also ob served.

Keywords: TNT | Denitrification | Biodegra