Airlift reactors with a bubbly flow are commonly used to add oxygen to the hypolimnion of lakes. However, there is no reliable information on the gas transfer that will occur in a field-scale airlift reactor. Gas transfer experiments are conducted inside a deep bubble column/airlift reactor containing air and water with a maximum aerated water height of 23.4 meters and diameter of 1.06 meters. The effects of geometry and operating conditions on gas transfer are determined. A two-phase convection-dispersion model is fit to the DO measurements using the liquid film coefficient (KL) as a fitting parameter. Sparger differences had a substantial effect upon KL, and the gas transfer coefficient for the airlift reactor was four times that of the bubble column. Results are characterized using Sherwood, Reynolds and Bond numbers. A low Reynolds number exponent was found, indicating that KL in a deep column tends towards a constant and is not highly dependent upon air discharge.