Where \(C_{k,SR\_ref}\) is the concentration of a reference source. In
the example above, the reference source should be source 2 when the
flowrate for source 1 is to be determined. Otherwise, if the flowrate of
source 2 should be determined, then source 1 should be used as the
reference source.
The freshwater reduction by reducing the flowrates of the sources is
only possible when the Pinch Point occurs at the non-limiting
contaminants. For example, if the Pinch Point occurs at the contaminant
’A’ after shifting the source CC in Figure 5a, the freshwater
requirement is already at the optimum level. There is no room for
further reduction. The ratio with the sink’s concentration with the
maximum source concentration ratio can be used as the indicator to
determine the limiting contaminant for the specific sink (see Section
2.2.1).