The model workflow proceeds as follows: First, the membrane feed solution enters an initial hypothetical DBSU, where the retentate and permeate stream properties leaving the unit are calculated using Eq. S7 -S12, in the order stated. Additionally, the membrane area required by the first DBSU is calculated from Eq. S13. The retentate stream of the first batch unit is then fed to a second hypothetical batch unit. Again, retentate and permeate stream properties as well as the required membrane area are calculated from Eq. S7 -S13, and the retentate of the second DBSU is fed to a third. This process is continued until the retentate of an n th DBSU reaches a satisfactory solute concentration. At this point, no further hypothetical batch units are added, and the retentate of the n th DBSU constitutes the retentate stream leaving the modelled CCSU. The permeate stream leaving the CCSU and the required membrane area of the CCSU are found through aggregating the individual permeate streams and membrane areas of all n hypothetical DBSUs (Eq. S14 -S20).