Controls for {HEAD ~ the process} allow for a wide variation in the amount of treatment chemicals used, dependent upon {TAIL ~ composition} of contaminants in the groundwater 
Controls for { HEAD ~ the process } allow for a wide variation in the amount of treatment chemicals used , dependent upon { TAIL ~ composition } of contaminants in the groundwater
OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH