A POTENTIAL APPLICATION OF MICROALGAE IN PRODUCED WATER TREATMENT

Abstract

Produced water, deriving from petroleum industry as a result of oil production, constitutes of high concentration of pollutants, such as dissolved nitrogen, phosphorus, dissolved organic carbon, heavy metals and monocyclic aromatic compound like BTEX (benzene, toluene, ethylbenzene, and xylene). Thus, removal of these pollutants from produced water is essential. Many conventional treatments are currently present, which often used for the produced water treatment. Most of the time, these treatments processes are costly and these processes increase the overall cost of oil production. As an alternative solution, microscopic microalgae can be used to remove these pollutants from the produced water effluents. These microalgae can bio-remediate produced water effluents while utilizing some of these pollutants as sources of nutrients. The current study examines pollutant removal efficiency of different microalgae species from produced water effluents. After initial screening, five species of microalgae strains Monoraphidium, Chlorella, Neochloris, Scenedesmus, Dictyosphaerium were chosen for the study. Chlorella and Dictyosphaerium species show a significant amount of biomass generation within all different concentration of produced water. Although the biomass yield of Neochloris strain was low, it was able to remove a higher amount of organic carbon than other microalgae strains. Although biomass generation was significantly varied within the microalgae strains, nitrogen removal efficiency by all the strains were similar. Also, similar results were also found for most of the BTEX component. Only in the case of phosphorus and various metals, removal efficiency was better by Dictyosphaerium microalgae species. However, the variation of produced water concentration has no significant effect on the pollutants removal efficiency of microalgae strains. Thus, the results indicate that microalgae strains can grow in produced water effluents-deriving from petroleum industries and remove pollutants.