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