The water contains {HEAD ~ a quantity} of pollutants, nutrients or {TAIL ~ other undesirable species} and has a pH on entry into the floway such that the algae is not prevented from growing by an excessively high or low pH, and such that the pollutants, nutrients or other undesirable species are generally dissolved, although some species may be present in the form of suspended particulate matter 
of
The water contains { HEAD ~ a quantity } of pollutants , nutrients or { TAIL ~ other undesirable species } and has a pH on entry into the floway such that the algae is not prevented from growing by an excessively high or low pH , and such that the pollutants , nutrients or other undesirable species are generally dissolved , although some species may be present in the form of suspended particulate matter
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH