Tailings are recycled back into the reactor and combined with {TAIL ~ fresh feed} for {HEAD ~ bubble control} 
Tailings are recycled back into the reactor and combined with { TAIL ~ fresh feed } for { HEAD ~ bubble control }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD