Estimation of Oxygen Transfer Rates for Mechanical Aerators in Brackishwater Aquaculture Ponds

Abstract

Oxygen transfer rates for mechanical aerators are usually determined by standard aeration tests conducted in concrete tanks. Results from standard tests are then extrapolated to field application of the aerators in aquaculture ponds, but these extrapolations have not been verified. In this study, oxygen transfer rates were estimated for propeller-aspirator-pump aerators deployed in brackish water aquaculture ponds under normal pond conditions. Estimation was accomplished by fitting the Whole Pond Respiration Diffusion (WPRD) model to nighttime observations of dissolved oxygen concentration for ponds in which artificial aeration had been initiated during the night. Application of this new technique revealed that oxygen transfer rate determined from a standard aeration test was similar to that estimated from trials in aquaculture ponds. Preliminary results suggest that oxygen transfer rates were higher when the aerator was placed in the deep end of the ponds than when the aerator was situated in the shallow end. Aeration efficiencies ranged from 1.45 to 1.8 kg O ₂ per kW-hour.