Remediation of petroleum-contaminated soil using a combination of single and mixed agricultural and forestry wastes with exogenous microorganisms

Biostimulation is an efficient and eco-friendly approach for addressing total petroleum hydrocarbon contamination, although it can be limited by environmental factors. Agricultural and forestry waste, being readily available and nutrient rich, enhances soil porosity and promotes a favorable environment for petroleum-degrading bacteria. In this study, a combined experiment was conducted using agricultural and forestry waste with the addition of exogenous Bacillus M1 microorganisms to remediate petroleum-contaminated soil. The results showed that rapid bioremediation was observed between Days 0 and 30, and the bioremediation rate declined from Days 30 to 60 as compared with the previous period. The efficiency of total petroleum hydrocarbon removal reached 82% to 86% with various combinations of waste and M1, and the highest efficiency was observed in the mixed agricultural and forestry waste group. In addition, analyses of soil physicochemical properties and enzyme activities indicated that the addition of agricultural and forestry waste with M1 significantly improved these properties and promoted microbial community succession, thereby increasing the abundance of petroleum-degrading microorganisms. A comprehensive analysis showed that the mixed agricultural and forestry waste group demonstrated the best overall performance. This study provides valuable data on integrating agricultural and forestry waste with exogenous microorganisms for the bioremediation of petroleum-contaminated soils.