The design methodology should start with contaminant cascade ’A’ first
as well. Figures 11 show the plot of the CC for both SK1 and SK3. The
source order should be SR1-> SR2 -> SR3
-> SR4. In Figure 11a, the Source CC is shifted to the
right until it touches the endpoint of SK1 line. It should be noted that
the Pinch occurs at contaminant ’A’. Since SK1 is determined as limited
by contaminant ’A’ , there is no room for fresh resource reduction for
SK1- step (i) in Section 3. After SK1 is fulfilled, the next sink to be
fulfilled is SK3. Figure 11b shows the plot of the CC with SK3 is
stacked above SK1. Notice the Pinch point occurs at contaminant ’B’, but
this is not the main limiting contaminant for SK3. The flowrate of SR3
should be reduced by mixing some of the SR4 to further reduce the
freshwater target for SK3. Using the proposed algorithm from Section
2.4/3, the reduced SR3 that can be allocated to SK3 is 42.7917 t/h, with
a little from SR4 to reach Pinch points for both contaminants. Figure
11c shows the plot of the CCs.
As for the sinks in contaminant cascade ’B’, a similar methodology is
applied. The source order is SR2-> SR4->
SR1-> SR3. SK2 is first to be fulfilled. As SR2 and SR1 are
allocated to SK1 and SK3, the sources that are remained are SR4 and SR3.
By performing PA, the Pinch Points of both contaminants are reached for
SK2, by using solely SR4 (see Figure 12a). This is the optimal
allocation for SK2. As for the next sink SK4, the Pinch Point also
occurs at contaminant ’B- see Figure 12b, which is its main limiting
contaminant. There is no room for further freshwater reduction in this
case.