Euglena viridis is a freshwater, single cell, mixotroph microalgae bearing a secondary chloroplast.

[2] Euglena viridis is common and cosmopolitan in bodies of water rich in organic compounds.

[9] In a wastewater biodegradation system, algae can provide the oxygen that heterotrophic bacteria need for the degradation of organic matter.

[11] The ability to live in polluted water bodies have let Euglena viridis be used as an oxygen producer in wastewater biodegrading system.

And it has been proven that Euglena viridis can enhance biodegradation in piggery wastewater degradation system.