Design of packed columns for commercial oxygen addition and dissolved nitrogen removal based on effluent criteria

Successful application of the packed column in fish culture requires a design based not only on oxygen supplementation rates (kg/day), or other standard performance indicators such as oxygen absorption efficiency (kg absorbed/kg applied) or transfer efficiency (kg/kWh), bvt also on dissolved nitrogen and total dissolved gas pressure limits and predicted changes across the system. Such a design procedure was developed by applying a mass balance on the gas and liquid phases of the system along with Henry's law and previously published packing-specific mass-transfer correlations. The design approach is unique in that column pressure and oxygen feed rates are calculated for target changes in dissolved oxygen and nitrogen without the use of iterative numerical procedures. An alternative calculation sequence was developed to establish the sensitivity of column performance to changes in oxygen feed rates at a selected column pressure or packed bed depth.