| 摘要 |
<p>A biological aerated filter comprises a filter vessel 11 with a base 13 supporting a media column 12 in the vessel, gas 14 and liquid 10 supply means supplying gas and liquid along the column, and backwashing means providing a backwash to clear collected biomass from the column and to reform flow channels through the column. Preferably waste water or sewage enters the filter from the bottom of the vessel 11 which may be constructed of steel or concrete, and flows through the base 13 which may be a block of stone, concrete and or a plastics material, and is then filtered by a sand or plastics particulate filter material which is supported by the base. Solids material or biomass collected on the filter material may be removed by a normal backwash of air, followed by air and water and followed by water. Flow channels through the column may be reformed by backwashing with water for a shorter period of time relative to the normal backwash.</p> |
