Long term impact of electrical resistance heating on soil bacterial community based on a field test.

Thermal remediation is an effective technology for organic contaminant remediation. However, the application of thermal remediation may have negative effects on soil properties and ecological functions, which requires further investigation. Based on a pilot test of electrical resistance heating remediation (ERH), soil samples were collected at different locations after heating for 116 days. Most soil physicochemical properties were less affected by the heating temperature difference. Application of high temperature increased microbial abundance but inhibited alpha diversity of the bacterial community. More significant changes in microbial communities were observed at temperatures above 60 °C. The genera mainly affected by heating temperature included Flavobacteria, Brockia, and S085, while the increase in temperature also inhibited the abundance of nitrochlorobenzene functional genes. At 140 days after the end of the pilot test, the bacterial community affected by thermal remediation could recover effectively, and the recovery of the bacterial community was not affected by temperature difference during the heating period. This study provides valuable field evidence of the long term impact of soil ERH treatment on soil properties and microbial communities, and provides further references for optimization of remediation performance with coupled technologies.