Abstract

An enhanced remediation of a contaminated garden soil in Niger Delta region of Nigeria was carried out using bioaugmentation-biostimulation (BB) protocols. The In-Vessel System of composting was employed for the production of biostimulants (biosolid and brewer’s spent grain) from the feedstocks and a strong hydrocarbon-degrading strain of Bacillus altitudinis (GenBank accession number KY569499.1 was used for the bacterization of the treated biostimulants. The total residual petroleum hydrocarbons (TRPH) were extracted from the soil samples and quantified using Gas chromatograph HP 5890 while gas chromatography (GC, Hewlett-Packard HP 6890 series) coupled to a mass spectrometer MS, model 5971, Hewlett-Packard) was used to quantify extractable organic (Polycylic Aromatic Hydrocarbons) PAHs. Biosolid was significantly (p < 0.05) more effective at driving TPH reduction (85.39-94.76%) depending on contamination level) in the soil than BSG (71.88-89.16%). The reduction of Σ17 PAHs in the contaminated beds was 55±3% higher in the remedied beds compared to the bed that was left for natural attenuation. It was obvious from this study that enhanced degradation occurred in beds contaminated and remedied using the Biostimulation-Bioaugmentation (BB) protocol. This was achieved by increasing their respective soil nutrient and the addition of a potent allochthonous hydrocarbon degrader (Bacillus altitudinis ). It may, therefore, be appropriate to recommend their use as a suitable biostimulant during the remed iation of agricultural land previously contaminated with hydrocarbon.