PURPOSE: To provide a biological denitrification process for exhaust gas, in which nitrogen oxides-containing exhaust gas is treated in a biologically stabilized manner at low cost.
CONSTITUTION: Nitrogen oxides-containing exhaust gas is brought into contact with sodium thiosulfate water solution in an absorption tower 1, and the nitrogen oxides in the exhaust gas are absorbed into the water solution, and oxidized by microbes carried on a solidifying carrier in the absorption tower, and further, the water solution is flowed into a fixed bed type reactor 2, and the nitrogen oxides are removed by microbes carried on a saddle type ceramic in the reactor in a biological denitrification process for exhaust gas. The nitrogen oxides can be treated stably at low cost from exhaust gas containing dilute nitrogen oxides of 10ppm or less, for example, exhaust gas in a tunnel from automobiles, by this process.
KITANO MAKOTO
TAKAGI TOSHIHIKO
ARITOME KIYOSHI
MIKI OSAMU
YABE HIDEAKI
