ABSTRACT
In the past fifteen years, the use of microalgae and cyanobacteria for wastewater treatment has been reviewed by many authors (LalibertC et al., 1994; de la Noiie et al., 1992; Lincoln and Earle, 1990; Oswald, 1988a, 1988b; 1991). These reviews demonstrate that algal cultures in high-rate oxidation ponds (HROP) for the removal of nitrogen and phosphorus in parallel with the production of a useful algal biomass can be an interesting alternative to conventional tertiary wastewater treatment. The most abundant algae found in the water of naturally managed HROPs are generally of the genera Chlorella, Ankistrodesmus and Scenedesmus. However, the removal of these small algae from the effluent can represent a major cost associated with algal cultivation on wastewater (Mohn, 1988). Furthermore, because well designed HROP can produce more than 200 kg dry mass of algae per hectare per day, disposal of the concentrated algal biomass requires convenient solutions.
