Investigation of aeration process in rotating disk ceramic membranes for aquaculture wastewater purification

Abstract

To enhance the separation efficiency of particles in the rotating ceramic membrane aeration process, this study employs the Eulerian two-fluid model and the Population Balance Model (PBM) to numerically simulate the gas-liquid two-phase flow within the reaction zone of the aeration device. The accuracy of the numerical calculation model is validated by comparing bubble diameters at different monitoring planes. The study investigates the impacts of different aeration rates, bubble diameters, and ceramic membrane rotational speeds on the characteristics of the two-phase flow field. The results are as follows: As the aeration rate increases, in the top part of the aeration tank, the water flow velocity and turbulence dissipation rate are relatively low, which is conducive to improving the flotation efficiency. When the aeration rate reaches 10 m³/h, the velocity and turbulent dissipation rate decreased significantly. When the bubble diameter is 20 μm, the velocity non-uniformity index inside the aeration tank is the lowest. When the bubble diameter increases to 100 μm, the water flow velocity and turbulence dissipation rate near the ceramic disc are at their minimum. As the rotational speed of the ceramic membrane increases from 30 r/min to 60 r/min, the flow field velocity and turbulence dissipation rate gradually decrease, while the gas content near the ceramic membrane increases significantly.