Similarly, the purified water is returned to {HEAD ~ the pool} of {TAIL ~ water} after ozone elimination, temperature adjustment and chlorination 
of
Similarly , the purified water is returned to { HEAD ~ the pool } of { TAIL ~ water } after ozone elimination , temperature adjustment and chlorination
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH