{HEAD ~ Presence} of brine water with {TAIL ~ a salinity} of 8 to 12% is crucial because it is used to regenerate the cation exchanger such that: 
{ HEAD ~ Presence } of brine water with { TAIL ~ a salinity } of 8 to 12 % is crucial because it is used to regenerate the cation exchanger such that :
HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH