Diagnosis of in situ air sparging performance using transient groundwater pressure changes during startup and shutdown

Groundwater pressure measurements during startup and shutdown of in situ air sparging (IAS) systems are used to diagnose air flow behavior below the water table. The magnitude of the pressure response provides insight into the permeability of the zone into which the air is flowing. The duration of elevated pressures during startup and reduced pressures during shutdown indicate the extent to which air is being trapped below the water table by lower-permeability layers. The pressure measurements can be easily and quickly repeated and as a result are useful for both pilot tests and for optimizing operating conditions of existing IAS systems. Whether used alone or in conjunction with other diagnostic tools, pressure measurements are an important tool for assessing IAS performance.