Biological Remediation of the Engine Lubricant Oil-contaminated Soil with Three Kinds of Earthworms, Eisenia Fetida, Eisenia Andrei, Dendrobena Veneta, and a Mixture of Microorganisms

The survival of the earthworms in used engine oil-contaminated soil with concentration of 20-100 g/kg was estimated. The investigation was made of the contaminated soil bioremediation efficiency with the use of Eisenia fetida, Eisenia andrei and Dendrobena veneta in presence of the photosynthetic bacteria Thiorhodaceae, Athiorhodaceae and Chlorobacteriaceae, nitrogen-fixing bacteria Azotobacter and Clostridium, yeast cells Saccharomyces, fungi Aspergillus and Penicillium, and Actinomycetales, composing microbiologic product Baykal EM. It is determined that the used oil concentration in the soils with earthworms decreases 4-10 times faster than in contaminated soil without earthworms. High rates of engine oil removal are registered in presence of E. andrei and D. veneta. Oil concentration in soil decreased by 60-90%. With oil concentration of 60-100 g/kg and earthworms (Eisenia fetida) cultivation, the oil concentration decreased 4-6 times, with introduction of Californian earthworms (Eisenia andrei) 12 times and with Dendrobena veneta 12-23 times. At the addition of the microbiologic product along with earthworms, oil content in the soil decreased 58 times and constituted 1.1 g/kg, soil remediation efficiency being 99.9%.