Emission of Volatile Organic Compounds and Greenhouse Gases from the Aerobic Bioremediation of Soils Contaminated with Diesel

Bioremediation is one of the most frequently used treatments for reducing high levels of organic contaminants from soil. This article complements previous work on the anaerobic bioremediation of soils contaminated with diesel, which has revealed the generation of high levels of greenhouse gases and volatile organic compounds by anaerobic bacteria activation. Unlike anaerobic methods that generate low concentrations of CH4 and CO2 regardless of the pollutant (mainly through the action of anaerobic bacteria), aerobic bioremediation methods yielded high concentrations of greenhouse gases and volatile organic compounds due to the breakdown of long molecular chains during bioremediation. The aim of this study was to characterise the greenhouse gases and volatile organic compound emissions produced during the aerobic bioremediation of diesel-contaminated soils. The soil was contaminated with 0.5, 2.0 and 4.0 % (w/w) diesel oil and stored in glass reactors for 90 days under aerobic conditions under abiotic processes, natural attenuation and biostimulation. The emitted gases were collected with charcoal cartridges and gastight syringes. Chemical analyses were performed by gas chromatography with multiple detectors. The results indicated high concentrations of CO2 (418.6 mg kg−1) and low levels of CH4 (2.69 mg kg−1), N2O (0.33 mg kg−1) and volatile organic compounds (VOCs) (0.30 mg kg−1).