Environmental problems caused by soil contamination can cause changes in the physical, chemical and geotechnical properties of the soil. Research on a suitable method for soil improvement has focused on the use of biological methods for soil improvement and remediation. Microbial calcium carbonate precipitation has been applied to solve many geotechnical problems. In this study, sandy soil was mixed with two conventional hydrocarbon pollutants and classic soil mechanics tests (compaction, direct shear, uniaxial and permeability tests) were implemented. The use of two bacterial solutions, two-phase injection and bacterial flocculation with injection of cementation solution, produced favorable results. Considering the lower inhibition of gasoline in low dilution, it was possible to improve with both methods. In the case of soil contaminated with motor oil, limitations on the use of microbial calcium carbonate precipitation were improved with the use of bacterial flocculation. The results of this approach were more suitable because the bacteria stabilized between the soil grains. XRD, SEM, EDS and wet chemical analysis were carried out to help confirm and interpret the results

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