At the point that 90 100% of the newly injected oxidant has been consumed, {HEAD ~ a second port} is used to introduce {TAIL ~ more oxidant} and water in a similar manner and under similar conditions 
is used to introduce
At the point that 90 100 % of the newly injected oxidant has been consumed , { HEAD ~ a second port } is used to introduce { TAIL ~ more oxidant } and water in a similar manner and under similar conditions
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH