Enhanced electro-osmotic dewatering of fine particle suspension using a rotating anode

Electro-osmotic dewatering (EOD) of 9.1 wt % bentonite slurry was investigated using a stationary and rotating anode. The rotational speed varied from 0 to 300 rpm. Excessive slurry is necessary to load beyond the anode initially to maintain good contact between the anode and the dewatered slurry. The water removed from the slurry increased significantly with the rotational speed initially and reached a plateau at 240 rpm. This increase is found to be due to the "falling off" of the dry cake from the rotating anode. The average solid content of the cake in the chamber after EOD can be 24.6 wt % with the anode rotating at 240 rpm and 3 times excessive initial loading of slurry. This solid content is 70.8% higher than that obtained using a stationary stainless steel anode. When a pin was inserted beneath the rotating anode, an optimal cake thickness of 5 mm was found in terms of water removal. The energy consumption for the process is <20% of the latent heat of water evaporation.