Effects of Temperature Gradient on Algae Inhibition Zone in Source Water Reservoirs Using <i>In Situ</i> Water-Lifting Aeration Technology

Abstract

Flow outside the water-lifting aerator was simulated with FLUENT software, and the effects of temperature gradient on the in-situ algae inhibition zone were numerically analyzed. Flow characteristics directly influence the effect of algal inhibition using water-lifting aeration technology. Under quasi-steady state of flow outside the water-lifting aerator, the clockwise flow near the inlet and counter-clockwise flow in other domains coexisted, zone and strength of inlet circulation weakened as the water temperature gradient increased, flow velocity decreased as the distance from the water-lifting aerator increased. When the temperature gradient within the depth of 30 m increased from 0.17 °C/m to 0.73 °C/m, the radius of the core algal growth inhibition zone increased from 100 m to 150 m, and the ratio of the algal growth inhibition zone to the whole flow domain increased from 25.16% to 28.60%. The proper design intervals of water-lifting aerators in reservoirs were proposed as 100m-150m.