Bioremediation of dissolved organic compounds in produced water from oil and gas operations using Chlorella sorokiniana: a sustainable approach

Abstract

The sustainable treatment of petroleum-derived produced water (PW), a significant byproduct of oil and gas extraction, presents a persistent problem due to the presence of organic pollutants. This study examines the potential of the microalga Chlorella sorokiniana (C. sorokiniana) for the bioremediation of dissolved organic pollutants in PW. The primary objectives were to evaluate the efficacy of C. sorokiniana in decreasing the levels of dissolved organic contaminants while examining its growth and survival in such a complex environment. The cultivation of C. sorokiniana in photobioreactors containing synthetic produced water (SPW), supplemented with synthetic municipal wastewater (SMW) to provide essential nutrients, was carried out under controlled laboratory conditions. Parameters such as biomass growth, lipid content, and the microalgae’s capacity to metabolize organic compounds are monitored over time. The results indicate that, except for 100% PW, maximum biomass output after 16 days ranged from 733 to 1077 mg/L. Total organic carbon (TOC) removal efficiency increased with rising PW concentrations, peaking at 85% for 50% PW. The cultivation period resulted in substantial nitrogen and phosphorus removal from the enriched PW media, achieving a maximum nitrogen removal of 87% at 10% PW and a phosphorus removal of 98.5% at 40% PW. Lipid content ranged from 12 to 16% during this period. In conclusion, C. sorokiniana offers a promising and sustainable approach for the bioremediation of dissolved organic compounds in PW. This method provides an eco-friendly option to reduce the ecological impact associated with petroleum-derived PW.