the amount of {TAIL ~ oxidant} injected in each port is effective to reduce {HEAD ~ the content} of organic matter in the stream by a predetermined amount in the primary stream, and 
the amount of { TAIL ~ oxidant } injected in each port is effective to reduce { HEAD ~ the content } of organic matter in the stream by a predetermined amount in the primary stream , and
OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH