Bioremediation of Soil Contaminated with Diesel and Biodiesel Fuel Using Biostimulation with Microalgae Biomass

This study evaluates the ability of biostimulation to enhance the bioremediation of soil contaminated with oily compounds as compared with natural attenuation. The soil was contaminated with 4% of diesel or biodiesel and biostimulated with phycocyanin (a proteic emulsifier extracted from the Spirulina platensis biomass), an inactive biomass of S. platensis, or ammonium sulfate. Experiments were conducted for 60 days, whereas the biodegradation was measured through the determination of carbon dioxide (CO2) evolution and oils and grease. Higher CO2 evolution was observed in the soil contaminated with the biodiesel and phycocyanin as biostimulant (2,997.35 mg C-CO2) and in the soil contaminated with diesel oil with the inactive biomass S. platensis as biostimulant (2,454.89 mg C-CO2). The highest biodegradation was achieved by using phycocyanin as a biostimulant for biodiesel contamination (88.75%) or inactive biomass of S. platensis (63.89%) for diesel as contaminant. Natural attenuation resulted in the lower CO2 evolution of 386.5 and 282.5 mg C-CO2 and biodegradation rates of 42.4 and 31.3% for biodiesel and diesel, respectively. (C) 2016 American Society of Civil Engineers.