Physicochemical Parameters Monitoring During Bioremediation of Soils Polluted by Hydrocarbons in Brazzaville (Congo)

Abstract

This work aimed to treat soils polluted by hydrocarbons using the bioremediation technique. Soils samples were taken from four (04) garages chosen in some districts of Brazzaville, namely Ouenzé, Mfilou, Djiri and Talangai. Four treatments were carried out for bioremediation treatment while monitoring physicochemical parameters by bioaugmentation, biostimulation and mixture of bioaugmentation and biostimulation. Several physicochemical parameters were monitored during the different treatments: The ranges of physicochemical parameters values are respectively between 23.3 and 28.4°C for temperature, between 38,6 and 5266,01µS/cm for conductivity, between 6.01 and 7,5 for pH,  between 0 and 70% for the maximum water retention capacity, between 1 and 10% for humidity, between 0 and 88 mg/Kg for nitrogen and between 0 and 298.93 mg/Kg for potassium. The Total Petroleum Hydrocarbons (TPH) concentrations in polluted soils decreased significantly throughout the treatments with a drop between 25% and 85%. The greatest drop (75%-85%) in hydrocarbon concentrations is observed for Bioaugmentation (Bacteria) and Biostimulation+Bioaugmentation (NPK+Bacteria) combination treatments. Thus, bioremediation by adding Bacillus genus bacteria would be an alternative way for the depollution of soils polluted by hydrocarbons.