EVALUATION OF THE ABSORPTION EFFICIENCY OF THE LOW HEAD OXYGENATION SYSTEM

The 'Low Head Oxygenation System' or LHO(TM) is a device recently patented for injection of oxygen or other gases into liquids, relying on serial reuse of oxygen through a series of chambers or stages. The device is especially suited for applications where the low hydraulic head limits the use of other oxygen injection devices. The LHO has recently been used to supersaturate water with oxygen for increased production of fish. In this study, the absorption efficiency of the LHO and nitrogen gas supersaturation concentrations were evaluated at five different oxygen gas to liquid ratios (G/L) ranging from 0.10 to 0.83% (0.40-3.20 g O-2/min). The mean absorption efficiency of the LHOs ranged from 67.3 to 90.6%, peaking at a G/L of 0.20% (0.79 g O-2/min). This oxygen flow corresponded to a mean dissolved oxygen concentration of 12-13 mg/liter entering the raceway. Absorption efficiency decreased as oxygen flows increased. Nitrogen gas saturation was inversely proportional to oxygen flow, and did not fall below 100% saturation until oxygen flows exceeded a G/L of 0.64% (2.50 g/min).