Life Cycle Assessment of Crude Oil-Contaminated Soil Treated by Low-Temperature Thermal Desorption and Its Beneficial Reuse for Soil Amendment

The effectiveness of thermal treatment technologies for the remediation of soils contaminated with heavy hydrocarbons has been extensively documented in the scientific literature. In general, high-concentration crude-oil-contaminated soil is treated with high-temperature thermal desorption (HTTD) in order to achieve high remediation efficiency. However, this process has the unintended consequence of destroying soil fertility. Low-temperature thermal desorption (LTTD) represents an alternative approach that has been developed with the objective of remediating heavily crude-oil-contaminated soil in a more rapid and cost-effective manner while simultaneously enhancing soil fertility. The thermal desorption unit (TDU) was employed using both LTTD and HTTD, operating at 300 °C and 500 °C, respectively, with a 30 min residence time in the kiln. The concentration of total petroleum hydrocarbons (TPH) in both the LTTD- and HTTD-treated soils was found to be less than 1% by weight, thereby below regulatory standards. The environmental impacts of both processes were assessed using the OpenLCA software version 2.0. The HTTD process exhibited a total abiotic depletion potential (ADP) impact of 1.63 × 10−4 MJ and a global warming potential (GWP) of 414 kg CO2-eq. In contrast, LTTD demonstrated lower impacts, with an ADP of 1.29 × 10−4 MJ and a GWP of 278 kg CO2-eq. The transition from HTTD to LTTD resulted in a notable reduction in ADP by 20.5% and in GWP by 32.9%. The application of LTTD-treated soil coated with coke or carbonized residues has been demonstrated to serve as an effective soil amendment, with the capacity to sequester approximately 50% of organic hydrocarbon contaminants. The results of this study illustrate the potential of LTTD for not only economical and rapid soil remediation but also the enhancement of soil quality through beneficial reuse.