**5.5 Bioventing**

Bioventing techniques involve controlled stimulation of airflow by delivering oxygen to unsaturated (vadose) zone in order to increase activities of indigenous microbes for bioremediation. In bioventing, amendments are made by adding

nutrients and moisture to increase bioremediation. That will achieve microbial transformation of pollutants to a harmless state. This technique has gained popularity among other in-situ bioremediation techniques [25].

## **5.6 Bioslurping**

This technique combines vacuum-enhanced pumping, soil vapor extraction and bioventing to achieve soil and ground water remediation by indirect providing of oxygen and stimulation of contaminant biodegradation [26]. This technique is planned for products recovery from remediating capillary, light non-aqueous phase liquids (LNAPLs), unsaturated and saturated zones. This technique used to remediate soils which are contaminated with volatile and semi-volatile organic compounds. The method uses a "slurp" that spreads into the free product layer, which pulls up liquids from this layer. The pumping machine transports LNAPLs to the surface by upward movement, where it becomes separated from air and water. In this technique, soil moisture bounds air permeability and declines oxygen transfer rate, which reducing microbial activities. Although this technique is not suitable for low permeable soil remediation, it is cost effective operation procedure due to less amount of ground water, minimizes storage, treatment and disposal costs.
