During oil production and processing activities, significant quantities of
oily sludge are produced. The sludge represents not only an environmental p
ollution source but also occupies big spaces in storage tanks. Romania, an
experienced European oil-producing and processing country, is faced with en
vironmental problems generated by oily sludge accumulations. Many such accu
mulations are to be submitted to bioremediation processes based on the hydr
ocarbon degradation activity of naturally occurring, selectively isolated b
acteria. In this paper the results concerning a laboratory screening of sev
eral natural bacterial consortia and laboratory tests to establish the perf
ormance in degradation of hydrocarbons contained in oily sludges from Otest
i oil field area, are presented. As a result of the laboratory screening, w
e selected six natural bacterial consortia (BCS1-I-6 to BCS1-I-6) with high
ability in degradation of hydrocarbons from paraffinic and non-paraffinic
asphaltic oils (between 25.53%-64.30% for non-paraffinic asphaltic oil and
between 50.25%-72.97% for paraffinic oil). The laboratory tests proved that
microbial degradation of hydrocarbons contained in oily sludge from Otesti
oil field area Varied from 16.75% to 95.85% in moving conditions (Erlenmey
ers of 750 ml on rotary shaker at 200 rpm) and from 16.85% to 51.85% in sta
tic conditions (Petri dishes empty set 10 cm or vessels of 500 ml). (C) 199
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