Author(s): FRANCO, M. G.; CORRÊA, S. M.; MARQUES, M.; PEREZ, D. V.

Summary: Bioremediation processes have been credited fo r reducing high levels of organic contaminants from soils. However, during bioremediation of dies el contaminated soils, for instance, diesel is converted to volatile organic compounds (VOC) and greenhouse gases (GHG), which means that such remediation technique contributes to th e greenhouse effect. The ongoing construction of a large petrochemical industrial region in Rio de Janeiro Metropolitan Area (COMPERJ) and the transportation of large volumes of oil byproducts (mainly diesel), have raised deep concerns regarding accidents that may re sult in soil and air contaminat ion. When the problem comes, remediation techniques shall be applied. The obj ective of this study was to characterize the emission of GHG and VOC during bioremediation of so ils contaminated with diesel oil in pilot scale. Soil samples contaminated with 0.5, 2.0 and 4.0 w/w% diesel oil were kept during 3 months in glass rectors (2 L internal volume) kept under an aerobic/anoxic conditions. The soil moisture was controlled at 80% of field capacity. Bioremediation processes were investigated with nutrient?s adjustment (biostimulation), no adjustment (natural attenuation) and sterilized soil (abiotic process). The gases emitted from different reactors were collected in activated carbon cartridges and the GHG were collected in Tedlar bags. The chemical analyzes were performed using a gas chromatograph (Agilent 7690) with multi-detection using FID for CH 4 , ECD for N 2 O and TCD for CO 2 . VOC were analyzed using a mass spectrometry detector (Varian 450GC MS220). The results indicated that gaseous sa mples contained high concentrations of CO 2 but low concentrations of CH 4 and N 2 O. The differences in composition of the gas emitted from the reactors regarding CO 2 were statistically not significant. Preliminarily, regarding VOC emissions, such as alkanes and alkenes (both branched), cy cloalkanes, and aromatic substituted (such as ethyl benzene), the compounds with higher emissions were cycloalkanes and branched alkanes.

Publication year: 2012

Types of publication: Paper in annals and proceedings

Unit: Embrapa Soils

Keywords: Bioremediation, GHG, Greenhouse gases, VOC