The global trend towards sustainable development with low carbon emissions has encouraged the expansion of nuclear energy. The nuclear reactors, under normal operating conditions or radiological emergency, generate different types of radioactive waste, mainly liquids and solids that require efficient and mobile treatment systems. This work presents the design proposal of a mobile dissolved air flotation system (mDAF) with a high rate for the treatment of liquid radioactive waste generated in the attention and response to radiological post-emergencies of nuclear power plants or environmental emergency responses associated with oil spills. The evidence obtained showed that the design used allows to reach, under the conditions of the experiment tested, removal levels higher than 95 % in the concentrations of oil waste, SO4-2, NO3-, PO3-3 , Ni and Cr. Removal levels of approximately 94 % and 75 % for the total Co and( 60)Co, respectively, were achieved. It was possible to demonstrate the feasibility of designing a mDAF of low cost with enough versatility to treat radioactive liquid waste generated in a radiological post-emergency. (C) 2020 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.