LABORATORY STUDY ON THE BIOREMEDIATION OF DIESEL OIL CONTAMINATED SOIL
FROM A PETROL STATION
Adriano Pinto Mariano1,3*; Ana Paula de Arruda Geraldes Kataoka2; Dejanira de Franceschi de Angelis2;
Daniel Marcos Bonotto1
1Instituto de Geociências e Ciências Exatas, Universidade Estadual Paulista, Rio Claro, SP, Brasil; 2Departamento de Bioquímica
e Microbiologia, Instituto de Biociências, Universidade Estadual Paulista, Rio Claro, SP, Brasil; 3Programa de Recursos
Humanos, Agência Nacional do Petróleo, Gás Natural e Biocombustíveis, Rio Claro, SP, Brasil.
The purpose of the present study was to investigate possible methods to enhance the rate of aerobic
biodegradation of hydrocarbons (ex-situ treatments). In this work, the bioremediation processes were applied
to a sandy soil with a high level of contamination originated from the leakage of a diesel oil underground
storage tank at a petrol station. Laboratory scale experiments (Bartha biometer flasks) were used to evaluate
the biodegradation of the diesel oil. Enhancement of biodegradation was carried out through biostimulation
(addition of nitrogen and phosphorus solutions or Tween 80 surfactant) and bioaugmentation (bacterial
consortium isolated from a landfarming system). To investigate interactions between optimizing factors, and
to find the right combination of these agents, the study was based on full factorial experimental design.
Efficiency of biodegradation was simultaneously measured by two methods: respirometric (microbial CO2
production) and gas chromatography. Acute toxicity tests with Daphnia similis were applied for examination
of the efficiency of the processes in terms of the generation of less toxic products. Results showed that all
bioremediation strategies enhanced the natural bioremediation of the contaminated soil and the best results
were obtained when treatments had nutritional amendment. Respirometric data indicated a maximum
hydrocarbon mineralization of 19.8%, obtained through the combination of the three agents, with a total
petroleum hydrocarbons (TPH) removal of 45.5% in 55 days of treatment. At the end of the experiments, two
predominant bacteria species were isolated and identified (Staphylococcus hominis and Kocuria palustris).
Keywords: Bioremediation, Soil, Diesel Oil, Petrol Station.
Corresponding author: Tel.: (+5519) 3526-4175;
Fax: (+5519) 3526-4176 .