A packed column oxygen obsorber was developed in which oxygen flow is directed, in serial reuse, through parallel packed column stages receiving equal portions of the liquid being treated. The relative performance of the absorber was established using a computer simulation program employing finite difference-mass transfer calculations. The program was calibrated using packing specific mass transfer coefficients derived from pilot scale test data. A separate series of tests served to verify model assumptions and performance predictions. Simulation data indicated multi-stage operation can substantially reduce the column height required to achieve a selected oxygen absorption efficiency (AE); for example, the column height required to achieve an AE of 76·5% with an inlet volumetric oxygenwater ratio of 0·008 (column packing, 3·81 cm plastic ACTIFIL®; water temperature, 20°C; influent dissolved oxygen, 9·08 mg/litre; operating pressure (absolute), 760 mm Hg) was 0·27 m using a 10-stage system versus 1·39 m using a single-stage absorber. Reductions in column height achieved were related to oxygen and water feed rates, number of stages employed, mass transfer characteristics of the column packing used, and concentrations of dissolved gases in the liquid being treated.
