ReviewInfluence of water salinity on the SOTR of paddlewheel and propeller-aspirator-pump aerators, its relation to the number of aerators per hectare and electricity costs

The objective of this study was to determine the standard oxygen transfer rate (SOTR) (kg O2/h) of 2-HP (1.49 kW) paddlewheel (PW) and propeller-aspirator-pump (PAP) aerators submitted to salinities of 0, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55 and 60‰. Tests were carried out in round 50 m3 tanks. SOTR of paddlewheel and propeller-aspirator-pump aerators was maximum (3.79 ± 0.30 and 3.62 ± 0.04 kg O2/h, respectively) at salinity 30‰. Above 30‰, efficiency of aerators was slightly reduced. These results suggest that it is possible to calculate the number of aerators according to the salinity of the culture ponds and, consequently, predict electricity costs.