Assessment of Heavy Metal and Oil-Contaminated Silty Sand Treatment by Electrical Resistance Heating Method

The feasibility of the electrical resistance heating method developed in this study was evaluated for the remediation of multi-contaminated silty sand in terms of environmental and geotechnical aspects. The multi-contaminated silty sand sampled in this study was polluted with 21,081 mg/kg of heavy oils, as well as heavy metals. Silty sand, treated using the electrical resistance _heating method was environmentally, as well as geotechnically, compared with the multi-contaminated silty sand in terms of residual concentration, leaching, shear modulus and modified California bearing ratio (CBR). The remediation test was conducted with a target temperature of 700 °C. The removal efficiency of total petroleum hydrocarbon (TPH) was estimated as 99.99% after remediation in 48 h; most of the heavy metals, as some of the contaminants, were isolated as a crystal in treated silty sand without any harmful leakage, and heavy oil was fully extracted with a form of mist and dust. Moreover, it was also geotechnically found that the decontamination process, including the removal of heavy metals and oils, had an effect on the increase in the internal friction angle, shear modulus and modified CBR of treated silty sand. In conclusion, it is shown that the electrical resistance heating method developed in this study is an environmentally and geotechnically effective technology for the recovery of clean construction fill material from hazardous-waste-contaminated silty sand.