High water recoveries can be achieved in brackish water RO desalination by air stripping of a carbonate-rich concentrate which induces high pH conditions leading to precipitation of the calcium hardness. Additional permeate can then be extracted from the RO concentrate stream after separating the precipitate. In our previous experimental study we have demonstrated the advantage of carrying out the CO2 air stripping process in a fluidized bed system. This paper presents a theoretical model enabling rigorous analysis of the experimental results and providing a framework for designing a fluidized bed CO2 air stripping system. (c) 2012 Elsevier B.V. All rights reserved.