Soil Corrosivity Under Natural Attenuation

This study investigated natural attenuation conducted in soil artificially contaminated with low-sulfur diesel oil, and to evaluate the corrosion of ASTM A36 carbon steel (A36) during the bioremediation process. Microbiological quantification of hydrocarbonoclastic bact & eacute;ria (HCB) and heterotrophic bacteria (Aerobic and Anaerobic) was carried out at 7, 14, 28, 42 and 56 days. Corrosion rate was quantified according to the NACE-SP-07-75 standard using the gravimetric method. Morphological analysis was conducted through Scanning Electron Microscopy. Results indicated a significant reduction of 24.03% in oils and greases in the soil, along with a respirometric degradation of 11.10%. Soil contamination with diesel led to microbial growth, mainly of HCB, during diesel bioremediation; however, there was no impact on the corrosion rate of A36. Soil corrosivity with diesel was classified as low after 56 days of experiment. These findings show that natural attenuation is a method capable of bioremediating soil with diesel without impacting nearby steel structures.