Application of Euglena gracilis in wastewater treatment processes

Microalgae strains can rapidly remove biogenic elements, which contribute to the eutrophication of water bodies, from wastewater. In recent years, interest in microalgae strains has increased significantly. This research aimed to assess the ability of Euglena gracilis G.A. Klebs (Euglenozoa) to reduce the concentrations of phosphorus and nitrogen in domestic wastewater to the level recommended by the EU legislation in a short time (4 days). In this study, wastewater with different nitrogen and phosphorus concentrations was used. E. gracilis reduced the concentration of phosphorus in the analyzed wastewater by 96–100% and that of nitrogen up to 63%. In addition, this study found that E. gracilis is resistant to high concentrations of these nutrients in water and accumulates biomass and photosynthetic pigments (chlorophyll a and carotenoids) with increasing concentrations of phosphates (from 4 to 14 mg/l) and ammonium nitrogen (from 30 to 90 mg/l). These results suggest that E. gracilis is a promising alga for biological treatment of wastewater to reduce phosphorus and nitrogen concentrations.