JPS56102933A - Method and apparatus for washing and circulating solid granules constituting fluid bed - Google Patents

Abstract

PURPOSE: To perform effective washing of solid granules with small amounts of treating water by a method in which the solid granules constituting a fluid bed for biological treatment are sent back to the fluid bed through an inverted funnel- shaped return pipe in such a way as to prevent the inflow of the granules into a withdrawing port and then washed by upwardly flowing water inside the return pipe.

CONSTITUTION: An inverted funnel-shaped return pipe 11 is inserted into a solid- liquid system fluid bed 2 so that the second fluid interface 12 can be produced at a place lower than the upper fluid interface 3 of the fluid bed in the inside of the large-diameter part of the return pipe 11. At the same time, the upward flow 13 of water is produced in the inside of the small-diameter part of the return pipe 11. On the other hand, the solid granules constituting the fluid bed is drawn out from near the upper part of the fluid bed 2, treated for removing contaminants or for other purposes, and then returned to the fluid bed 2 through the return pipe 11. Also, the solid granules are subjected to countercurrentwise washing using the upward flow 13 of water inside the return pipe 11 to remove the separated sludge and the sludge is discharged through a sludge discharge pipe 22 to the outside.

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