Evaluation of the Emissions from the Pyrolytic Treatment of PAHs Soil Contaminated Soil

Abstract

The present paper examines the emissions of polycyclic aromatic hydrocarbons (PAHs) resulted from the thermal treatment through pyrolysis process of contaminated soil with petroleum products. Specifically, across the experimental work, the process temperature influence on PAHs and Phenanthrene emissions and remediation degree during the thermal treatment were investigated. The pyrolytic treatment of the contaminated soils was performed at different temperatures and time: 400C for 60 min; 600C for 30 min and 800C for 30 min. The obtained results revealed that non-oxidative atmosphere at temperatures between 400C and 800C reduced PAHs and Phenanthrene to below regulatory standards. More than that, it was evidenced that, when the initial concentration of the contaminants in soil is not too high (content of PAHs in soil was 26.811 mg/kgd.w. respect to 25 mg/kgd.w., while for Phenanthrene initial concentration in soil was 19.264 mg/kgd.w. respect to 5 mg/kgd.w. from the regulation in force) even a low-temperature of 400C for the pyrolysis process ensure an efficiency in removing PAHs and Phenanthrene higher than 99%. It was evidenced that, increasing the process temperature with 200C and respectively with 400C, respect to the selected pyrolysis conditions as appropriate (400C for 60 minutes), has no relevance in terms of reducing contaminants from the contaminated soil. This is an important advantage considering that lower temperatures are requiring lower energy costs and soil fertility is not affected as in case of soil incineration or other thermal treatment methods.