| 摘要 |
<p>A liquid treatment tank (1) with a liquid inlet (2) contains a layer of components (4) having buoyancy in the liquid. During treatment the liquid is directed so that it premeates through the layer. During treatment the layer is stabilised by restricting the buoyancy of the layer in the liquid. This may be done by maintaining the level of the liquid below the surface of the layer with the outlet stand pipe (7). The layer filters the liquid of particles alone, or together with soluble material. When the apparatus is to be serviced for removal of particles from the layer the buoyancy of the layer is released. This provides for loosening of the components and the particles can be freed from the interstitial spaces of the layer. The particles are released to a position below the layer and may be discharged from the tank. The invention can for example be applied to the mechanical and biological filtration of impurities from waste water.</p> |
