Resumen

ARAUJO, Ismenia et al. STABILIZED SLUDGES AND BACTERIAL STRAINS FOR BIOREMEDIATION OF OIL CONTAMINATED SOILS. INCI [online]. 2006, vol.31, n.4, pp.268-275. ISSN 0378-1844.

Summary The utilization of native bacterial strains and application of stabilized sludges during bioremediation of a soil were studied using contaminated soil from field "Moga", Zulia state, Venezuela. Bacterial strains were isolated and evaluated in their ability for gasoil degradation (feasibility). The four most efficient oil degrading strains were used as a mixed culture in the study of oil hydrocarbon degradation. Fertilization by nitrogenous and phosphorus, stabilized sludges from a lagoon system in a carbon free source environment were utilized during 150 days. Total hydrocarbon (TPH), total Kjeldahl nitrogen, total phosphorus and metal concentrations, saturated, aromatics, resins and asphalt fractions, mesophylic heterotrophs, electric conductivity, temperature and pH were determined. Sludges, soil and lixiviate showed permissible total metal contents according to permitted environmental standards. Significant differences were obtained (P<0.05) in treatments for the mesophylic heterotrophs and TPH removal variables. The highest hydrocarbon removal averages were obtained (Tukey) on treatments containing 15 and 10% of mixed culture plus sludge. The population density values were 19 and 27x109CFU/ml for treatments with mixed culture and sludge, and a total hydrocarbon removal of 90 and 74%, respectively. These treatments showed a highly significant (P<0.001) positive correlation between the degradation of the TPH and bacterial growth with the compostage, and revealed a higher removal of saturated, aromatic, resin and asphaltene fractions, demonstrating the efficiency of the technology used in the bioremediation of oil contaminated soils.

Palabras clave : Biotratamiento; Cepas Autóctonas; Compostaje; Contaminación; Hidrocarburos.