Characteristics of activated sludge-separation using a rotating disk magnetic separator

摘要

In waste water treatment processes, a large pool forsedimentation is used for solid-liquid separation after biologicaltreatment. As a substitute for this pool, we are developing amagnetic separator that has a rotating disk with Nd-Fe-Bpermanent magnets. Activated sludge flocs are magnetized bymagnetic seeding using ferromagnetic fine particles. This paperdescribes a method of predicting the separation characteristics,based on calculation of the particle trajectory. As the flow-outratio is very sensitive to the particle size, the calculation takesaccount of the particle diameter distribution. However thecalculated results for the flow-out ratio are much higher than theexperimental results. The reason is that the calculation is based onthe particle diameter measurement which is not suitable forevaluating the condition of particle cohesion. Our next task is todevelop a method of measuring particle diameters like that used inthe magnetic separator.