Evaluation of Vapor Extraction Method for Removal of Benzene and Toluene from Contaminated Soil and Effect of Organic Matter Contents on the Removal Efficiency

Benzene and toluene are considered as perilous hydrocarbon compounds, which their exposure could lead to health hazards in both human and the environment. In this research, the efficiency of Soil Vapor Extraction (SVE) on removal of these two hazardous hydrocarbons from soil and effect of organic matter contents on the removal efficiency has been investigated. The soil screening levels (SSLs) were also determined using the USEPA guidelines and, subsequently, those levels were compared with the contaminants concentrations after remediation to figure out if SVE was a suitable method for removal of benzene and toluene. The experiments were carried out by collecting soil samples from a petrochemical complex in south of Iran. The extraction of contaminants was conducted by applying a constant rate vacuum through the samples which were placed in a glass cylindrical vessel. The samples were tested at the organic matter contents of 3.5%, 5.5%, 7.5%, and 9.5%. The results of the study indicated the highest removal efficiencies of 97% and 82% achieved for benzene and toluene, respectively, in the samples with the lowest soil organic matter content of 3.5%. A comparison of remains contaminants concentrations at the end of test with the soil screening levels indicated that SVE technique is a suitable method for remediation of the volatile components. Also, it was concluded that the reductions in organic matter of the specimens would enhance the efficacy of the SVE method in treatment of benzene and toluene-contaminated soil.

Keywords:

Soil Vapor Extraction , Benzene , Toluene , Organic Matter Content , Soil Screen Level