TITLE:
Effect of Combining Bioremediation and Air Stripping on Soil Remediation System Using Synthetic Surfactants to Enhanced VOCs Desorption
AUTHORS:
Stephen Yakubu, Adeola Grace Olugbenga, Yetunde Mariyam Aladeitan, Abdullahi Zakari
KEYWORDS:
Surfactant, BTEX, Remediation Techniques, Bioremediation, Air Stripping, Hybrid Treatment System
JOURNAL NAME:
Advances in Chemical Engineering and Science,
Vol.16 No.4,
October
16,
2026
ABSTRACT: The optimization of a MATLAB-based integrated model has been carried out. In this, a surfactant-enhanced hybrid bioremediation-air stripping system employed in the efficient removal of benzene, toluene, ethylbenzene, and xylene (BTEX) from petroleum-contaminated soils was investigated and compared with standalone bioremediation, air stripping, and conventional integrated treatment systems. Conventional remediation methods for volatile organic compounds (VOCs) rely on physicochemical and biological processes that primarily transfer BTEX from the solid phase into the gaseous phase without incomplete degradation. In this study, soil samples were collected from four locations within the NNPC/PPMC Suleja Depot, Niger State, Nigeria, and identified as clay, loamy, sandy and coarse-grained soils. The removal efficiency of the air stripping processes (ASPs), the bioremediation, and the hybrid treatment system was evaluated under varying operational conditions. The hybrid treatment configuration consisted of ASPs coupled with a bioreactor unit to enhance BTEX removal efficiency. BTEX was selected as the model compound for assessing system performance under different temperatures and surfactant formulations, namely MNS-1, MSDS-2, and MMS-4. Maximum BTEX recoveries were achieved within 1.5 h for ASPs and 30 days for bioremediation under controlled experimental conditions. The overall BTEX removal efficiencies increased from 47.12% - 56.74% for bioremediation, 45.68% - 50.66% for ASPs, and 64.29% - 83.26% for the hybrid system. The MATLAB-optimized hybrid model achieved superior removal efficiencies ranging from 96.84% - 98.71% as air velocity increased from 0.1 to 4.0 cm∙s−1 and 95.24% - 98.18% for MMS-4 surfactant concentration rises from 0.01 to 3.00 wt% when temperature increased from 20˚C to 50˚C. A mass transfer and diffusion model was developed using MATLAB response surface methodology. The diffusion coefficient increased from 1.84 to 3.19 m2∙s−1 with increasing air velocity and temperature, indicating enhanced BTEX transport and volatilization. The results revealed the synergistic interaction between air stripping and bioremediation that improved BTEX desorption, biodegradability, and overall degradation efficiency. This implies that BTEX removal was strongly influenced by temperature and significant surfactant concentration.