en |
Assessment of bioremediation of aliphatic, aromatic, resin, and asphaltene fractions of oil-sludge-contaminated soil
Minai-Tehrani, D.; Rohanifar, P. & Azami, S.
Abstract
Oil sludge is a viscous material consisting of
resin, asphaltene, sand, and water, which is usually formed
at the bottom of oil reservoir tanks. Asphaltene and resin
contents of oil sludge make it more resistant to biodegradation.
Disposal of oil sludge is the main problem of oil
industry; discharge of oil sludge into the soil causes damage
to the environment. Bioremediation is an efficient,
cheap, and environmentally friendly method for oil-sludge
treatment. The aim of this study was to investigate the
biodegradation of oil-sludge fractions in contaminated soil
for a period of 12 months. The oil sludge was mixed with
soil with the final concentration of 5 % (w/w), and the
nutrients such as phosphate and nitrate salts were added to
soil. Finally, reduction of aliphatic, aromatic, resin, and
asphaltene was tested. The results showed that the reduction
of total petroleum hydrocarbon was 31 ± 5 % during
12 months of the treatment. About 60 ± 8 % of total aliphatic
fractions, mainly C14–C22, decreased. Analysis for
the detection of two, three, and four rings of polycyclic
aromatic hydrocarbons demonstrated about 42 ± 3 %
reduction of total aromatic fractions, whereas the resin
(6 ± 0.8 %) and asphaltene (4 ± 0.5 %) fractions were
slightly biodegraded. In conclusion, biotreatment of oil
sludge during 12 months could well reduce aliphatic and
aromatic fractions, but more time is needed for resin and
asphaltene reduction.
Keywords
Biodegradation; Oil-sludge fractions; Polycyclic aromatic hydrocarbons; Soil contamination
|