Simultaneous bioremediation of petrochemical effluent and production of nutrients-rich biomass by the microalgae Chlorella sorokiniana

Petroleum refining and byproduct production involve processes that utilize large volumes of water, which results in the generation of substantial amounts of effluents discharged into the environment. This study aimed to develop a non-chemical-dependent, eco-friendly, and cost-effective method for petrochemical wastewater treatment. Laboratory studies involved culturing Chlorella sorokiniana for seven days in five effluent concentrations: 100%, 75%, 50%, 25%, and 5% (v/v) by diluting petroleum wastewater with distilled water. The results showed that physico-chemical parameters and nutrient levels were higher in the untreated effluent than in the treated. Cultures with 5% and 75% effluent concentrations had 100% phosphate and nitrate removal, respectively. Those grown in 50% effluent produced the highest cell density of 2.99 × 104 cells/mL. Cultures grown in 100% effluents produced the highest chlorophyll-a, chlorophyll-b, and total chlorophyll levels at 0.45 pgcell−1, 0.74 pgcell−1, and 1.20 pgcell−1, respectively. C. sorokiniana grown in 25% effluents, in which the highest lipid and protein levels were recorded, also showed low levels of glutathione transferase activity. Growing microalgae in petrochemical effluents is a natural wastewater treatment method for cultivating microalgae because of their beneficial biomass and biomolecules.