Radioactive sewage and wastewater decay treatment system and treatment method thereof

The invention relates to a radioactive sewage and wastewater decay treatment system and a treatment method thereof, relates to the technical field of sewage treatment, and aims to solve the technicalproblem that generated radioactive sewage cannot be treated when a radioactive sewage treatment tank is cleaned. The system comprises a sewage collection tank, a first decay tank and a second decay tank, and the sewage collection tank is communicated with a collecting water pipe; and the sewage collection tank is provided with a first delivery pump used for lifting sewage in the sewage collectiontank into the first decay tank and a second delivery pump used for lifting sewage in the sewage collection tank into the second decay tank, the first decay tank is provided with a first discharge pumpused for discharging the sewage treated in the first decay tank to a drainage system, and the second decay tank is provided with a second discharge pump used for discharging the sewage treated in thefirst decay tank to the dra