Water removal from sludge in a horizontal electric field

A new method for sludge dewatering was proposed, in which a horizontal elec tric field was applied in order to facilitate the dissipation of gases prod uced at electrodes and to keep the anode soaked in water during the dewater ing process. The effects of operation conditions such as the magnitude of e lectric field strength, pH of aqueous phase, the pretreatment procedures in cluding flocculation, freezing and heating on the water removal were examin ed, respectively. The morphological difference between the concentrated slu dge produced by electrodewatering and by vacuum filtration was revealed wit h scanning electron microscopy, which shown that electrodewatering was effe ctive in removing the capillary water in the sludge floc. At electric field strength of 1200 V/m, the sludge concentration could be increased from 3 t o 8%(w/w), indicating that over 60% of water was removed from the sludge. C ompared to those operated in a vertical electric field, the method describe d in the present study has the advantages in terms of high efficiency, simp le structure and ease of operation.