| 摘要 |
PROBLEM TO BE SOLVED: To provide a gravitational apparatus for dehydrating/concentrating sludge, which is used at the preceding step of a final dehydration step of making a sludge cake and in which sludge is concentrated efficiently by forming a hollow part by using filter cloth and continuously using the filter cloth so that sludge is filtered by the filter cloth and water being filtrate is discharged through the hollow part by the natural action of gravity without using driving power and to provide a method using the gravitational apparatus for dehydrating/concentrating sludge. SOLUTION: The method for concentrating sludge at the preceding step of the final dehydration step of making the sludge cake comprises the steps of: settling water-containing sludge to separate it into a sludge layer and supernatant water; hanging a dehydrator in the separated supernatant water so that the filter cloth in the lower portion of the dehydrator is immersed in the supernatant water; filtering the supernatant water by the filter cloth; discharging the filtrate through the hollow part; gradually lowering the dehydrator to immerse a new surface of the filter cloth in the supernatant water whenever the amount of the filtrate to be discharged becomes low, so that the whole supernatant water is discharged as the filtrate; and immersing the whole of the dehydrator in the sludge layer, so that water in sludge is discharged through the filter cloth and the hollow part as the filtrate. COPYRIGHT: (C)2007,JPO&INPIT
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