Patent Number: 
Section: abstract

To provide an apparatus for treating a nitrate waste liquid that includes a denitrification tank (12A) which accommodates active sludge that adsorbs or takes in the radioactive substance in a nitrate waste liquid (11) and in which an anaerobic microorganism that reduces the nitric acid to nitrogen gas grows, and a reaeration tank (14) in which a denitrification-treated liquid (24) treated in the denitrification tank (12A) is aerated and mixed with active sludge. A pH adjuster (21), a first carbon source (22A) and a second carbon source (22B) different in type from each other, and nitrogen gas (N2) are supplied to the denitrification tank (12A) so as to separate a denitrified liquid into a solid content and the denitrification-treated liquid (24) by using a first solid-liquid separating film (25), and the denitrification-treated liquid (24) treated with the active sludge in the reaeration tank (14) is reaerated and separated into a solid content and a reaeration-treated liquid (27) by using a second solid-liquid separating film (28).