Biosurfactant‐assisted recovery and remediation of hydrocarbons from oily sludge using a mobile aerated washing system

BACKGROUND The oil industry generates oily sludge, the accumulation of which poses a serious environmental problem. Conventional methods require high costs, specialized equipment, and qualified personnel. This waste can be treated using biosurfactants. This study treated a sample of oily sludge with a biosurfactant, aiming to recover and/or degrade the hydrocarbons present. The biosurfactant was produced by the yeast Starmerella bombicola ATCC 22214, cultured in a medium containing crude cottonseed oil and sucrose. RESULTS Biosurfactant production reached 63.9 ± 0.5 g/L, with a surface tension of 32.08 ± 1.06 mN/m. The biosurfactant was isolated and structurally characterized as an anionic glycolipid, with a critical micelle concentration of 650 mg/L, corresponding to a surface tension of 31.78 ± 0.3 mN/m. The biomolecule showed little change in its surface tension across a wide pH range, at different temperatures, and at different NaCl concentrations. It was non‐toxic to cabbage, cherry tomato, and the microcrustacean test organism ( Artemia salina) and could disperse 80% of the oil in seawater under static conditions, as well as when applied in a simulation of wave agitation. Its potential as an adjuvant agent in the remediation of petroleum hydrocarbons was demonstrated through microbial growth dynamics. Finally, the biosurfactant was tested in a Mobile Aerated Sludge Washing System (MASWS), constructed to simulate in situ application in the treatment of oily sludge, achieving a washing efficiency of 75.05%. CONCLUSION Thus, the anionic glycolipid produced demonstrates viability as a biotechnological additive to mitigate the environmental impacts of the oil industry.