[Biodegradation of 2, 4- and 2, 6-dinitrotoluene in a pilot-scale system for soil contaminated with explosive compounds].

A pilot-scale system consisting of a soil biodegradation tank, a denitrification tank, and a recirculating feeding tank was designed and applied to study the biodegradation of 2,4- and 2,6-dinitrotoluene in soil contaminated with the explosives. The experimental results showed that 2,4- and 2,6-DNT can be degraded completely by native DNT degrading bacteria existing in the contaminated soil, despite water temperatures as low as 8℃ to 15℃. Compared to 2,4-DNT, the biodegradation of 2,6-DNT was much slower and took much longer time. The alkalinity and nutrient needs of the bacteria were supplied by the soil with no additional amendments required. The denitrification system played an important role in preventing nitrite inhibition of DNT biodegradation, but it was necessary to supply an additional carbon source to ensure complete nitrite removal.