a portion of the algal turf is harvested after pollutants, such as phosphorus, have precipitated onto and/or into the cell walls of the algae forming the algal turf. The harvested algal turf may contain atleast 2.0% phosphorus, for example, per unit dry weight of algae. When phosphorus is precipitated according to the invention, the harvested algal turf may comprise at least 1.5% phosphorus in the form of phosphate precipitated on the walls of the algae. In addition, if phosphorus in the form of particulates is in the water, adjustments may be made to algal biomass and/or composition to also trap the particulates. Such trapping would increase the phosphorus content of the harvested algal turf in somesituations to about 5% of dry weight. A significant portion of the phosphate obtained is attributable to the site-specific precipitation action provided by the method of the present invention. The actual level is a function of many variables, including concentration in the wastewater, the relative particulate versus dissolved concentration of the phosphorus, and how the floway operational parameters are controlled. However, of the 5% dry weight maximum amount cited, approximately 0.5% is due to metabolic uptake, at least 2.0% due to precipitation, and at least 1.5% due to particulate trapping. Clearly, the precipitation element is very important to the efficiency of pollution removal on a large scale.