U-Tube Oxygenation Operating
Characteristics
R. E. SPEECE, Associate Professor of Civil Engineering
JACK L. ADAMS, Research_Assistant
New Mexico State University
Las Cruces, New Mexico
INTRODUCTION
Oxygen transfer to water is a vital process in water quality management. It
is involved in water and wastewater treatment processes, river re-oxygenation,
reservoir oxygenation, fish hatchery operation, etc. In some cases, the rate of
oxygen transfer which takes place under natural conditions is sufficient to maintain satisfactory water quality. Increasing urbanization and industrialization commonly overtax the oxygenation capacity of water resources. In such cases, supplemental oxygenation must be provided to restore and maintain desirable water
quality.
OXYGENATION OF WATER
The oxygen transfer process is characterized by the following equation:
dC = KL(A)(CsAT-CACT)dT
dC = change in dissolved oxygen (DO) concentration, mg/1
Kl = transfer coefficient, ft/hr
A    = area of air-water interface, ft2
V   = volume of water, ft
CSAT = saturation concentration of DO, mg/1
CACT = actual concentration of DO, mg/1
dT = time elapsed, hrs
An increase in any one of the four terms on the right side of the equation increases
oxygen transfer. All of these terms are under the control of the engineer in de-
designing oxygen transfer equipment.
Oxygenation of water is accomplished by different methods. Four basic oxygenation methods are shown in Figure 1. Another method of oxygenation, termed
U-Tube oxygenation, was developed in the Netherlands and reported by Bruijn
and Tuinzaad (1). Figure 2 is a diagram of their original system. The water to
be aerated was passed through a constriction which caused an increase in water
velocity and a negative pressure. Tubes which terminated at the flow constriction extended above the water surface and thus allowed air to be drawn into the
water. The air-water mixture passed down under a baffle, which extended 50 ft
below the surface.   Then it flowed back up to the surface.
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