Separation of petroleum hydrocarbons from soil and groundwater through enhanced bioremediation

In this study, enhance air biosparging techniques were investigated for remediating VOC-contaminated subsurface. Desired injection manners were acquired through batch- and bench-scale experiments in order to reduce the operating costs, eliminate the need for off-gas treatment, and enhance the efficiency of contaminant removal. The fate of benzene in water and water-soil systems under a variety of conditions was examined. Blank experiments were conducted to compare the efficiencies of different enhancement measures in promoting biodegradation. The effects of soil properties and injection manners on benzene removal were investigated through a number of experimental runs. The results indicated that using pulsed air injection in an air biosparging system could significantly reduce benzene concentration in both the pure fine-sand-without-clay system and the system with 95% fine sand and 5% clay. The rates of aerobic biodegradation for benzene in both water and water-soil systems were generally high in the study systems. Also, the effect of clay content (in fine sand) on benzene removal is significant at low airflow rate. The removal efficiency generally decreases with the increase of clay content.