Thermal Desorption Treatment of Soil Contaminated with Polychlorinated Biphenyls from Transformer Spills

Abstract

Polychlorinated biphenyls (PCBs) released from transformer spills represent a significant environmental concern due to their toxicity, persistence, and potential bioaccumulation in soil ecosystems. This study investigates the application of thermal desorption technology for the treatment of PCB-contaminated soil under controlled heating conditions. The research focuses on evaluating contaminant removal efficiency, thermal behavior, and operational parameters influencing the desorption process. Experimental analyses were conducted to examine the effects of treatment temperature, heating rate, residence time, soil moisture content, and airflow conditions on PCB volatilization and overall remediation performance. Results demonstrated that thermal desorption effectively removed a substantial fraction of PCB contaminants by promoting volatilization and separation of hazardous compounds from the soil matrix. Higher treatment temperatures and optimized residence times significantly improved contaminant removal efficiency while minimizing residual PCB concentration in treated soil. The process also reduced soil toxicity and enhanced the potential for safe disposal or reuse of remediated material. Thermodynamic and kinetic evaluations revealed that desorption efficiency is strongly dependent on heat transfer characteristics and contaminant diffusion mechanisms within the soil structure. Comparative assessment with conventional remediation techniques indicated that thermal desorption offers faster treatment rates, improved contaminant destruction efficiency, and reduced long-term environmental risk. Furthermore, appropriate process optimization minimized secondary emissions and energy consumption during operation. The findings highlight the potential of thermal desorption as an effective and environmentally sustainable remediation technology for managing PCB-contaminated soils originating from industrial transformer spills and hazardous waste sites.