Pilot bioremediation of contaminated soils by hydrocarbons, from an electricity production and distribution site in Ouagadougou, Burkina Faso

The bioremediation of polluted soils by hydrocarbons is a set of decontamination techniques which exploit the depolluting activity of living organisms in order to reduce the toxicity, mobility or quantity of a contaminant in the environment. This work has enabled the bioremediation of a soil contaminated with hydrocarbons by exploiting endogenous microorganisms of the environment. The depollution method used was the "off situ" treatment. Thus, a pilot sample of polluted soil excavated on a site was conveyed to another site accommodating a structure specialized for the biotreatment of the polluted environments. The soil was successively placed in heaps ("heap 1" and "heap 2") on two compartments of a treatment platform and submitted for 08 months to  bio-pollution with an improvement in the living conditions of endogenous microorganisms like contribution of substrates,  periodic watering and reversal of the medium. Previously, a pre-treatment was carried out on the samples including screening, breaking of large fragments of soil and homogenization. A total oil reduction rate of 62.32% was observed for "heap 1" and 67.92% for "heap 2". The temperature, pH and humidity of the two heaps were varied, respectively between 16 and 39°C, 6.5 and 8 and 35 and 80%. Otherwise, microbiological analysis showed a proliferation of aerobic microflora such as bacteria and molds in the two soil piles. Key words: Hydrocarbon, polluted soil, bioremediation, microorganisms.