A multicriteria approach for assessing the recovery of soil functions following high-temperature remediation of hydrocarbons

Abstract

The recovery of soil functions following thermal remediation is a key-step in soil reclamation, which depends on the adopted strategy. To date, no strategy has been proposed for soils treated by smoldering (600–1000 °C). This study therefore aimed to develop reclamation strategies for tropical soils treated by smoldering. For this purpose, Cenchrus alopecuroides and Miscanthus sinensis were grown on these soils for 46 days, following three reclamation strategies based on organic amendment and N-P-K fertilization. A multicriteria approach, based on soil physical, chemical, and microbial analyses, and reflectance spectroscopy, was proposed to assess the recovery of essential soil functions. The proposed strategies successfully recovered soil functions following strong alterations of soil properties induced by smoldering. The best strategy coupled the organic amendment and N-P-K fertilization, thereby contributing to restructure the soil and leading to healthy plant biomass production, in comparison to the untreated soil. Microbial biomass and communities also recovered, and soil TPH degradation was stimulated. Multiple regression analysis emphasized the relative importance of soil total organic carbon and total nitrogen, and root growth, to ensure the recovery of soil biological functions. Hence, this study shows promising outlooks for large-scale implementation of reclamation trials.