1. Introduction 2. Survey of Low-contaminated Sludge andSludge Separation Technology 2.1 Survey on the Status of Low-contaminated Sludge 2.2 Sludge Separation Technology Case Study 3. Sampling of Low-contaminated Sludge,Analysis of Radionuclides and ChemicalCharacterization 3.1 Results of Low-contaminated Sludge Analysis 4. Nuclide Removal Experiment of LowcontaminatedSludge 4.1 Washing Treatment and Ultrasonic Treatment 4.2 Chemical Elution and Substitution 5. Conclusion REFERENCES