Potential of cyanobacterial biofilms in phosphate removal and biomass production.

ABSTRACT

Four cyanobacterial biofilms, raised from cyanobacterial mats and dominated by Phormidium and Oscillatoria spp., were successfully grown attached to polyester mesh discs, and were tested for their probable application in [Formula see text] -P removal from domestic sewage and other nutrient enriched wastewaters. Biofilm # 2, dominated by Phormidium fragile, best removed [Formula see text] -P; nevertheless, some of it also grew outside the substrate making harvesting difficult. Other biofilms also efficiently removed [Formula see text] -P from the medium in the following order Biofilm # 1 > Biofilm # 3 > Biofilm # 4. Their growths were restricted to discs and are therefore better candidates as they can be efficiently harvested after [Formula see text] -P removal. [Formula see text] -P removal was primarily due to its uptake during growth of the biofilm rather than because of precipitation as pH of the medium remained <8.5. [Formula see text] -N concentration in the medium determined [Formula see text] -P removal efficiency of the test biofilms and therefore optimum NP ratio is necessary for optimizing [Formula see text] -P removal. The test biofilms could also efficiently remove [Formula see text] -N from the medium.