ABSTRACT: Environmental concerns about the contamination of groundwater and sea as a result of oil refining and transportation have encouraged scientists to seek sustainable and cost-effective methods to clean up these pollutants. Ammonia removal by green microalgae Chlorella vulgaris in media containing 10 mg/L ammonia and different concentrations of petroleum hydrocarbons was studied. The experiments were carried out in an airlift photobioreactor. Laboratory experiments showed that low concentrations of hydrocarbons not only did not inhibit ammonia removal but also had benefits for increasing the rates of biomass production and ammonia removal. Ammonia removal was obtained 100%. And hydrocarbon removal was obtained 100%. Based on the results obtained; microalgae utilize hydrocarbons as a carbon source. In addition, Chlorella vulgaris was a flexible and resistant microalgae to unfavorable conditions and quickly adapted to the low-contaminated culture solution. This feature increased the potential of Chlorella vulgaris to remove ammo
