Use of the biostimulation of indigenous microbial communities to degrade total petroleum hydrocarbons in contaminated soil

Abstract

This study examined the best option for remediating soil contaminated with crude oil through the addition of the inorganic nutrients C:N:P (yeast extract-glucose, NH4Cl-NaNO3 and K2HPO4-K3PO4), in order to increase the degradation of TPHs in the soil. To the contaminated soil a physicochemical characterization was made to know the initial conditions of the inorganic nutrients. The controlled conditions in the biostimulation strategy were 20 days of incubation under uncontrollable ambient temperature conditions. Responses measured after the experiments were residual TPHs, surface tension, respiratory activity and microbial counting. After an incubation period of 20 days, the best treatments found were Y5, which contains the nutrient source glucose-NaNO3-K3PO4, and Y4 (yeast extract-NH4Cl-K2HPO4), with degradation efficiencies of 14.0 and 12.8%, respectively. Biostimulation with inorganic nitrogen and phosphorus increased the metabolic activity of indigenous microorganisms in the soil and thereby increased the degradation of petroleum hydrocarbons. The Y5 and Y4 treatments can be considered as suitable for use as a biostimulation strategy in soils contaminated with TPHs.