Effect of cell concentration on the removal of nitrogen and phosphorus in synthetic wastewater by the immobilized algal-bacterial system

An immobilized algal-bacterial symbiosis system is established by the combination of single-cell Chlorella pryenoidosa with activated sludge in PVA for simulation of the removal of nitrogen and phosphorous in wastewater. It shows that the removal rate changes with the concentration of cells. The optimal concentration is V_(cells)∶V_(water)=1∶4.5. In the optimum system, the removal rate of nitrogen is 76.79% and that of phosphorus is about 90%. The removal efficiency declines obviously if the concentration of cells is too low (V_(cells)∶V_(water)=1∶9) or too high (V_(cells)∶V_(water)=1∶3, 1∶2.25, and 1∶1.8).