US researchers find Chlorella vulgaris algae removes pollutants from wastewater

US researchers have found that a single-celled fresh water algae Chlorella vulgaris is effective in eliminating pollutants from wastewater even at fluctuating levels.

The study, which was published in Water Environment Research, indicates that Chlorella vulgaris removes harmful elements such as nitrogen and phosphorous from wastewater even when one kind of pollutant is not present. Some algae, however, need both nitrogen and phosphorous for them to be functional, thereby restricting their effectiveness in treating wastewater.

University of Arkansas Department of Civil Engineering associate professor Wen Zhang said: “One of the factors that significantly impacts algal wastewater treatment is nutrient availability.

“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.”

Quality of wastewater fluctuates significantly and this makes it tough to maintain algae growth for treatment. However, this study now indicates that this specie of algae can survive even in the absence of either nutrient.

For the study, Zhang teamed up with John Chamberlin, a doctoral student in the environmental dynamics programme, and Kristen Harrison, an undergraduate honors student in the Department of Crop, Soil, and Environmental Sciences.

The environmental engineers grew the algae in synthetic wastewater under several nutrient-limiting conditions besides in effluent from two wastewater treatment plants. It was found that the algae could effectively remove both nitrogen and phosphorous.

The research is funded by the Arkansas Biosciences Institute and the University of Arkansas Doctoral Academy.