Air sparging system is used to injecting air directly into groundwater. It remediates groundwater by volatilizing contaminants and enhancing biodegradation. As the bubbles rise, the contaminants are removed from the groundwater by physical contact with the air and are carried up into the unsaturated zone. As the contaminants move into the soil, a soil vapor extraction system is usually used to remove vapors. The addition of oxygen to contaminated ground water and soils also enhances biodegradation of contaminants in and above the water table, as it acts as a nutrient for bacteria. There are several enhancements for air sparging.