COMPREHENSIVE EVALUATION OF THE EFFECTIVENESS OF SORBENTS BASED ON IMMOBILIZED HYDROCARBON-OXIDIZING BACTERIAL STRAINS (FIELD AND LABORATORY STUDIES)

Abstract

Environmental contamination by petroleum products, which in modern Ukraine has assumed a catastrophic military nature due to damage to critical infrastructure, poses a threat of nationwide ecocide. The high toxicity and carcinogenicity of petroleum hydrocarbons migrating through trophic chains necessitate the implementation of effective "green" accelerated biodegradation technologies using sorbents with microorganism-degraders.

OBJECTIVE. To evaluate the effectiveness of a biopreparation based on an oil-absorbing sorbent with immobilized active strains of hydrocarbon-oxidizing actinobacteria (Dietzia maris, Gordonia rubripertincta, Rhodococcus erythropolis) under various application algorithms, and to compare the degree of petroleum hydrocarbon biodegradation under laboratory and field conditions.

MATERIALS AND METHODS. Studies were conducted under laboratory (modeling) and field (in situ) conditions at industrial power substation sites in Dnipro. Sanitary-chemical analyses of oil content (transformer and waste motor oils) were performed using gravimetric and IR spectroscopic methods. Microbiological parameters were assessed using plating and culture techniques on selective media. Statistical processing of data was carried out using SPSS 16.0 and STATISTICA 8.0 software packages.

RESULTS. In the field experiment under conditions of severe initial contamination (up to 94,700.0 mg/kg) and application of an integrated algorithm (biosorbent application of 2–4 kg/m², loosening to a depth of 40 cm, and moistening up to 60%), the degree of transformer oil biodegradation reached 83.4–97.9% after 9 months. Under laboratory conditions (ex situ), autonomous treatment of waste motor oil without moistening or nutrient maintenance ensured reliable spatial localization of the spill (at sorbent doses of 60–80% of the pollutant mass), but the total hydrocarbon elimination after 180 days reached only 10.1–21.8% due to moisture and nutrient deficiencies.

CONCLUSIONS. The evaluated biopreparation demonstrates high bioremediation potential; however, the rate and extent of biodegradation critically depend on environmental conditioning. To achieve the full metabolic potential of immobilized strains, adherence to protocols involving aeration, moistening, and nutrient supplementation is mandatory.