|Budget Amount *help
¥1,300,000 (Direct Cost : ¥1,300,000)
Fiscal Year 1994 : ¥500,000 (Direct Cost : ¥500,000)
Fiscal Year 1993 : ¥800,000 (Direct Cost : ¥800,000)
An experimental apparatus for electroosmotic dewatering which mainly consists of a dewatering vessel, a piston for mechanical compression, filter media and electrodes was made. A sludge bed packed in the apparatus can be dewatered electroosmotically by applying an A.C.field with changing frequency and wave form. The sludge bed also can be compressed mechanically by the piston under a constant pressure with proceeding of electroosmotic dewatering, in order to always keep contact between the bed and electrode well. Zieclite and bentonite clays were used as the experimental material. For zieclite, constant A.C.voltage of rectangular and sine waves were applied to the bed with changing the frequency in the region of low frequency under about 1 Hz. For bentonite, on the other hand, constant D.C.was passed through the bed with electrode reversal by changing electrode polarity at an interval of a certain long time. The results obtained by the experimental investigations are summarized as follows :
1.Electrosmotic dewatering under A.C.field could be performed in the low frequency below 1 Hz, regardless of wave forms, and final dewatered amount in a certain lower frequency was increased more than that under D.C.field.
2.The final dewatered amounts under same frequency were the same regardless of the wave forms. When the electric current passing through the bed is almost not changed with time, the frequency condition in that case is considered to give maximum final dewatered amount.
3.The dewatered amount per unit electric power consumption under the rectangular wave became greater with decreasing the frequency compared with that under the sine wave. However, the dewatering efficiency under A.C.field was lower than that under D.C.field.