https://phys.org/news/2019-01-micro-algae-ability-wastewater-treatment.html

"One of the factors that significantly impacts algal wastewater treatment is nutrient availability," said Wen Zhang, associate professor in the Department of Civil Engineering. "What is the ideal range of nitrogen-to-phosphrous mass ratio for algal growth? Because previous research failed to identify this, the efficacy of algal treatment has been difficult to predict or optimize."

Wastewater quality fluctuates dramatically, which makes it difficult to initiate and maintain algae growth for treatment. Zhang's study now shows that Chorella vulgaris could survive even in the absence of either nutrient.