Development of a composition and evaluation of the effectiveness of a bio-based product for cleaning oil-contaminated soils

Soil pollution by oil and petroleum products is a serious environmental problem, especially relevant for industrialized regions. Microbiological remediation based on the use of oil-oxidizing microorganisms is a promising method of restoring polluted soils. The aims of the study are to develop a composition and assess the effectiveness of a specialized bio-based product adapted to the climatic conditions of northwest Russia. Bacterial strains capable of utilizing petroleum products as the only carbon source have been selected and cultivated. Based on laboratory tests, a consortium of microorganisms was selected, including strains of Acinetobacter sp. (VKM B-3202), Rhodococcus erythropolis (VKM Ac-858 T) and Pseudomonas alcaligenes (VKM B-1295), and their growth activity was evaluated. Three biologics compositions have been developed, differing in the proportions of bacterial suspensions by volume, and the technology of their application to oil-contaminated soils has been determined. The effectiveness of cleaning soils contaminated with oil and petroleum products (gasoline, diesel fuel, oil products from a spill at the Tammisuo railway station (Vyborg) at temperatures of 10-20 °C, typical for the climate of the region, was studied in laboratory conditions. At a temperature regime of 20±1 °C and natural soil moisture, after 60 days of the experiment, the maximum concentration reduction rates reached 75.59 % for crude oil, 71.97 % for oil products from the spill, 90.53 % for diesel fuel, 75.81 % for gasoline. At a temperature of 10±1 °C – 40.62 % for crude oil, 49.58 % for oil products from the spill, 69.06 % for diesel fuel, 68.10 % for gasoline. The results of the study confirm the effectiveness of the developed bio-based product for oil-contaminated soil purification in the climatic conditions of northwestern Russia.