Evaluation of the activity of biodegradation of microorganisms in the recovery of soils contaminated by hydrocarbons Evaluación de la actividad de biodegradación de microorganismos en la recuperación de suelos contaminados por hidrocarburos

Abstract

The biodegradation activity of microorganisms in the recovery of soils contaminated by hydrocarbons was evaluated. Two initial concentrations of total petroleum hydrocarbons (TPH) were used: 4.7% and 6.5%, to which hydrocarbon-degrading microorganisms (MDH) and phenol-degrading microorganisms (MDF) were applied. 2x2 factorial experimental design was used with two replications, the treatments were T1: Soil with TPH 4.7% + MDH, T2: Soil with TPH 4.7% + MDH / MDF, T4: Soil with TPH 6.5% + MDH , T5: Soil with TPH 6.5% + MDH / MDF and two controls T3: Soil with TPH 4.7% and T6: Soil with TPH 6.5% without application of MD. The amount of microorganisms applied per treatment corresponded to the ratio of 0.3% by weight of the soil to be remedied. To each was added nutritional supplement tripo1ifosfato de sodio and urea 46%. The experimental unit were plastic trays with a capacity of 10 kg each of contaminated soil. The bioassays were carried out for 62 days. The results showed that the percentage of removal was higher in T1: Soil with TPH 4.7% + MDH and T4: Soil with TPH 6.5% + MDH with 68% and 66% respectively. The use of the mixture Degradador de hidrocarburos (MDH) + Depends of Phenols (MDF) in% of removal was greater for T2: Soil with TPH 4.7% + MDH / MDF with 65%. The Fisher LSD test (0.05) determined significant differences for concentrations of hydrocarbons A (4,51) and B (6,51) with averages of 1,60 TPH and 2,52 TPH respectively, which means, at a lower initial concentration of TPH, greater efficiency of applied biodegradable microorganisms.