Field Study on Remediation of PAHs Contaminated Soil by <i>Ex Situ</i> Technologies at a Coking Site

Abstract

Decontamination level and residual amount of polycyclic aromatic hydrocarbons (PAHs) were investigated by ex-situ remediation technologies including biopile, soil washing and thermal desorption in a field level. After the remediation, 16 USEPA priority PAHs were decontaminated from 99.3% to 99.9% for thermal desorption, from 17.9% to 82.1% for biopile and from-27.6% to 84.3% for soil washing. Residual PAHs amount in soils by thermal desorption was below the local soil screening level, differently from that by biopile and soil washing. Especially for high molecular weight PAHs, i.e. 5-6 rings PAHs, residual amount exceeded over the screening lever 4 to 197 times for biopile and 17 to 421 times for soil washing. Additional factors, such as cost, time, operation and maintainance etc. for remedial technology selection and contaminant bioavailability in soil matrix for remediation target values, were proposed to be paid more attention for specific contaminated sites.