In situ remediation of PAH contaminated soil by combination of biodegradation and Fenton reaction

摘要

The in situ remediation of PAHs in soil from a creosote oil contaminated site was studied. Treatment of the contaminated unsaturated soil combined the advanced oxidation process of Fenton-like treatment with biodegradation of the contaminants. The soil was contaminated with up to 19mg PAHs/g and free phase of creosote oil was present at the site. Over two weeks, hydrogen peroxide (8-9%, 900 L) was injected in 4 to 5m depth. Prior to hydrogen peroxide injection the total numbers of bacteria ranged from 4 x 10~8 to 2 x 10~9 cells/g horizontally and from 3 x 10~8 to 2 x 10~9 cells/g vertically. On average 53/62% (horizontally and vertically) of the bacteria were viable. After termination of the injection the numbers of bacteria were at the same order of magnitude as prior to the treatment. Indigenous soil bacteria utilized sole PAH compounds of up to 100mg/L in bioassays. The in situ biodegradation of PAHs will be further monitored.