| 摘要 |
<p>The invention relates to a submerged aerated filter for filtering sewage. The filter comprises a filter vessel 11 with a base 13. The base 13 supports a non-plastics particulate media column 12 in the vessel. Gas and sewage are pumped into the bottom of the column 12 and flow upwardly along the column 12. The particles have an average diameter of greater than 10 mm and are normally made from blast furnace slag or stone. This provides a column 12 that is very economical to produce and is not easily disturbed by the fluid flow through the filter. <IMAGE></p> |
