Nutrient removal from secondary effluent by filamentous algae

Abstract

The nutrient removal potential of filamentous Oscillatoria sp. was quantitatively studied. Oscillatoria sp. showed satisfactory growth on secondary activated sludge effluent supplemented with 1% NaHCO₃. Continuous open culture of Oscillatoria sp. was kept stable using a continuous stirred tank equipped with a filter-separator. Kinetic constants Y_N and Y_P were 10.6 g cells/g NO₃-N and 37.7 g cells/g PO₄³⁻ respectively through the analysis of the results of continuous culture experiments. Monoalgal continuous culture of more than 90% purity could be maintained for 6 months without contamination. The harvested Oscillatoria cells were proven to have an excellent filterability. They also have excellent autoflotation. The amino acid composition of the Oscillatoria algal protein compares favorably with the tentative standard for ideal protein defined by FAO/WHO.