Effect of temperature gradient on algal inhibition by in-situ water-lifting aeration in a stratified reservoir

Based on the method of computational fluid mechanics, flow velocity and algae concentration outside the water-lifting aerator were numerically modeled, the simulation results were compared against the field data. Under water depth of 80 m, when the temperature gradient increased from 0.17°C /m increased to 0.73°C/m, the radius of core zone for algae control increased from 100 m to 150 m, ratio of the algae control zone to the whole flow domain slightly increased from 25.16% to 28.60%, the time required for complete mixing of algae increased from 16d to 24d. The residence time of algae under the compensation point was longer than 48h for each simulation case, but it was not sensitive to the temperature gradient, the algal growth was effectively inhibited. Simulated profiles of water temperature and algae concentration agreed well with the measured ones. The proper spacial distance between two water-lifting aerators could be determined as 250 m.