Development of sodium nitrate waste fluid treatment technology by biological method

Takahashi, Kuniaki ; Meguro, Yoshihiro  ; Kawato, Yoshimi; Shibata, Katsushi*

Low level liquid waste discharged from Tokai Reprocessing Plant includes high concentration of sodium nitrate. In the case that the solidified waste are disposed under the ground, leached nitrate migrates into the environment and impacts on surround. To avoid this impact, we planned to apply the biological treatment system to reduce nitrate from this waste liquid. To solve the assignments that biological treatment technology has, we tested and obtained the results as shown below; (1) The amount of sludge ash could be cut down a tenth as much as usual. The disposal cost reduction of waste is just in sight. (2) Treatment performance could be improved up to 7 kg-N/m/d from 4 kg-N/m/d. It could be expected the more compact system by improvement of the membrane set into the biological treatment tanks.