Surfactant Enhanced Washing of Soil Contaminated with Petroleum Hydrocarbons and Treatment of Produced Wastewaters Using a Biofilter

Wastewater generated by washing a real petroleum hydrocarbon-contaminated soil was treated using a submerged aerobic filter. The wastewater contained petroleum hydrocarbons, surfactants, and other compounds that leached during the soil washing process. The efficiency of the biological treatment using natural or synthetic surfactants on the hydrocarbon-contaminated soil washing process, and different operation temperatures (24, 28, and 32°C) were compared and the identification of the microbial consortium present in the biofilter was carried out. The best degradation efficiency (73% hydrocarbon removal) was obtained when the wastewater from the soil washing using locust bean gum was treated at the biofilter operated at 24°C. The microorganisms found in the microbial consortium in the biofilter were B. subtillis, C. jeikeium, Pseudomonas sp., A. sobria, A. caviae, E. sakazakii.