Gas thermal remediation of an organic contaminated site: field trial

This paper investigated the performance of in situ gas thermal remediation (GTR) technique for the remediation of organic contaminated soil and groundwater. The pollutants of the site are mainly benzene, chlorobenzene, and petroleum. To evaluate the effectiveness of GTR, 100-m² site soil with a depth of up to 18 m were installed with heating wells and extraction wells. The temperature in the GTR system was 100~200 °C, and the pressure was 0.5~2.0 kPa. It ran for 34 days. Later, soil and groundwater were sampled 7 days after treatment. The results show that the temperatures of the central remediation area and the heating well surrounding area were higher than that of the edge position. The average temperature of the surface soil was the lowest. The highest temperatures were found at depths of - 3 m and - 6 m. In addition, the removal rates of benzene, chlorobenzene, and petroleum in soil were up to 99.81%, 99.72%, and 98.23%, respectively. Meanwhile, those for groundwater were up to 98.77%, 97.70%, and 99.99%, respectively. The removal rate of pollutants in soil is affected by temperature and the nature of the soil. Although many GTR projects have been applied in the USA, this project is the first engineering application project of GTR technology in China. The results present the good in situ organic removal efficiency of GTR system in this study and therefore provide a guidance and technical support for similar projects in China.