Influence of static magnetic field on sludge properties

The study investigated the influence of static magnetic field on sedimentation of activated sludge, coagulation efficiency in the bioreactors and dewaterability of the sludge. The sedimentation was improved when magnetizers were applied on the bioreactor and on the settling tank. The application of magnetizers only on the settling tank decreased the sedimentation properties of the sludge. The filamentous bacteria Type 0092 dominated in both bioreactors, but the significant differences were observed in its length. No effect of the static magnetic field on coagulation with the utilization of iron-based coagulant was observed. However, the static magnetic field enhanced coagulation with the utilization of aluminum-based coagulant. The results suggest that increased sedimentation of colloids and activated sludge, can in practice mean a reduction in the size of the necessary equipment for sedimentation with an unchanged efficiency of the process. Moreover, static magnetic field significantly reduced the COD concentration in filtrate and shorted capillary suction time during the dewaterability of waste activated sludge. (C) 2017 Elsevier B.V. All rights reserved.