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