Apparatus and method for treating radioactive nitrate waste liquid

An apparatus for treating a radioactive nitrate waste liquid, comprising:

• a denitrification tank that accommodates active sludge which adsorbs or takes in a radioactive substance in a nitrate waste liquid containing nitrate and the radioactive substance and in which an anaerobic microorganism that reduces the nitrate to nitrogen gas grows;
• and
• a reaeration tank that aerates and mixes a denitrification-treated liquid treated in the denitrification tank with active sludge in which the aerobic microorganism grows, wherein
• the denitrification tank includes:
• a pH adjusting unit that supplies a pH adjuster used for adjusting pH of the nitrate waste liquid;
• a carbon-source supplying unit that supplies a carbon source to the denitrification tank;
• a first solid-liquid separating unit that separates a denitrified liquid treated with the active sludge into a sludge-containing solid content and a denitrification-treated liquid;
• and
• a gas supplying unit that is arranged on a lower side of the first solid-liquid separating unit and supplies gas not containing oxygen into the denitrification tank, and
• the reaeration tank includes:
• a second solid-liquid separating unit that further separates the denitrification-treated liquid treated with the active sludge into a sludge-containing solid content and a treated liquid;
• and
• an air supplying unit that is arranged on a lower side of the second solid-liquid separating unit and supplies air into the reaeration tank.