Microbial degradation of waste hydrocarbons in oily sludge from some Romanian oil fields

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 9 Elsevier Science B.V. All rights reserved.