| 摘要 |
<p>A clarifying tank, eg a settlement tank, comprises a peripheral weir 2, with water flowing upwardly towards the weir and a buoyant medium 9 retained in the upward flow path. Preferably the buoyant medium consists of polythene tube-like members adapted to support microbiological growth, the members being held in a layer or basket-type mesh 8 and retained adjacent the weir. The buoyant medium may be retained at or below the surface 3 of the water. Preferably the medium is at least 100mm in depth. The clarification tank may be part of a sewage treatment system where the water is subject to biological oxidation prior to entering the clarifying tank.</p> |
