Stimulation of indigenous anaerobic microorganisms for bioremediation of the geological environment polluted with petroleum products
I. V. Trusei1,2, Yu. L. Gurevich2, V. P. Ladygina2, S. V. Fadeev3, Yu. P. Lankin2
1Krasnoyarsk State Pedagogical University named after V. P. Astafiev, Krasnoyarsk, Russia
2Federal Research Center “Krasnoyarsk Science Centre of the Siberian Branch of Russian Aсademy of Science”, Krasnoyarsk, Russia
3JSC Minusinskaya Hydrogeological Partу, Krasnoyarsk, Russia
Keywords: bioremediation, groundwater, petroleum products, psychrophilic microorganisms, denitrifying, sulfate-reduci
Abstract
Changes in the number of anaerobic microorganisms (denitrifying, sulfate and iron-reducing) in ground and groundwater polluted with oil products were investigated when bioremediation was carried out. It was shown that in the studied geological media the number of psychrophilic microorganisms of anaerobic groups (denitrifying, sulfate and iron-reducing, as assessed by the number of the colony-forming units on the respective cultivation media) was higher than the number mesophilic ones. When N, P, K-fertilizers were introduced into the contaminated zone, the number of psychrophilic microorganisms changed more significantly, both increasing and decreasing. When the ground in the aeration zone was treated, the number of anaerobes decreased, probably due to competitive displacement by aerobes. The number of hydrocarbon-oxidizing and ammonifying microorganisms increased by an order of magnitude and amounted to 106 CFU/g and 106-107 CFU/g, respectively. When fertilizers were added to groundwater, the number of anaerobic microorganisms increased by 1-4 orders of magnitude, the number of denitrifiers reached 105 CFU/ml, whereas the CFU number of sulfate-and iron-reducers was 103-104 and 102-103 CFU/ml, respectively. It was revealed that simultaneously with increase of the CFU numbers some chemical properties changed indicating intensified biodegradation of petroleum products. In particular, an antiphase changes in the ammonium and nitrate concentrations were observed due to the decomposition of petroleum products, nitrification and denitrification, as well as the concentration of bicarbonate and sulfate ions due to sulfate reduction.
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