Volume 36, N. 3

September-December 2013

Remediation Techniques Applied in Residual Clayey Soil (Oxisol) Contaminated by Diesel and Biodiesel


Volume 36, N. 3, September-December 2013 | DOWNLOAD PDF (8 downloads)


Biodegradation in residual basaltic soil contaminated by diesel fuel and biodiesel was assessed by three different techniques comprising natural attenuation, bioaugmentation, and bioventing. The soil was described in terms of its physicochemical and microbiological characteristics, showing favorable bioremediation conditions. Natural attenuation was monitored throughout the experiment. Bioaugmentation was performed using bacteria pre-selected from the soil at the concentration of ~3.0 ×106 CFU mL-1. In the bioventing process, the soil was aerated during a period of 4 h a day at a pressure of 280 kPa. Bioremediation was assessed by counting the colony forming units (CFU g-1 of soil) and by degradation of contaminants using gas chromatography for 120 days. The highest microbial density was observed at 30 days in natural attenuation and at 60 days in bioaugmentation and bioventing. Biodiesel-contaminated soils had the largest microbial activity and highest degradation of carbon chains. At 120 days, bioaugmentation was the most efficient bioremediation technique, with the largest biodegradation rate for the light fraction of diesel (78.5%) and for biodiesel esters (98.6%). Bioventing was more efficient than natural attenuation for both contaminants, indicating the presence of aerobic bacteria at the analyzed soil depth.

Keywords: Bioremediation, Microorganisms, Contaminants, Aeration, Residual soil,

Submitted on April 08, 2013.
Final Acceptance on August 02, 2013.
Discussion open until April 30, 2014.
DOI: 10.28927/SR.363275