To prevent the stirring-up of sludge and to discharge high quality water by a method in which in a tank in which the inside is partitioned into an aeration chamber and a drain chamber by a partition wall, the lower end part of the partition wall is slanted toward the aeration chamber, and the circular flow in the aeration chamber is controlled lest the flow enter the sludge precipitation part of the bottom part.
Garbage sent to a solid-liquid separation and solid decomposition tank 14 with water is filtered and separated into solid and liquid. Next, the solid is nitrated by microorganisms, and wastewater sent to a flow rate regulation tank 15 is stored and aerated here, and aerated in a water treatment tank 1. Besides, sludge 9 precipitation-separated in the tank 1 is returned the a decomposition tank 14 to be decomposed and nitrated. In the tank 1, the inside is partitioned into an aeration 3 and a drain chamber 4 by a vertical partition wall 2, and in the lower end part of the partition wall 2, an inclination part 2a slanted to the aeration chamber 3 at an angle of 30-60° to a vertical surface is installed so that the sludge 9 precipitated in a sludge precipitation part 13 is prevented from being stirred up.
FUJINO ETSURO
SHINPO HIDETO
YAMADA HIDEAKI
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