Solid-liquid separating method

TL;DR: In this article, the authors proposed a method to make gravity settling and separation possible and to make operation and maintenance easy in treatment of waste water by activated sludge by separating treated water and the sludge of active carbon and activated liquid by using the treated water produced in other stages as a diluting water.

Abstract: PURPOSE:To make gravity settling and separation possible and to make operation and maintenance easy in treatment of waste water by activated sludge by separating treated water and the sludge of active carbon and activated sludge by using the treated water produced in other stages as a diluting water. CONSTITUTION:Waste water 4 is introduced into an aeration tank 1, where air 5 is blown and the org. components in the waste water are decomposed away by activated sludge. At the same time, powdery active carbon 6 is added in the form of slurry into the tank 1 to about 1:1-2 ratio with the activated sludge, whereby the mixed state with the activated sludge is created. Thence, the mixed liquid contg. the powdery active carbon and the activated sludge are conducted from the tank 1 to a dilution tank 2, where treated water 10 is circulated as diluting water 7 with a pump. Thence, the liquids are conducted into a settling tank 3, where the treated water and the mixed sludge are gravity settled and separated. Since the mixed sludge is active carbon, the dewatering is improved and the solid-liquid separation is accomplished in a sufficiently short time by gravity settling.