| 摘要 |
1391691 Trickling filters A SCHREIBER 27 March 1972 [1 April 1971 1 July 1971 8 Oct 1971] 14315/72 Heading C1C In a trickling filter process in which waste liquid is purified by passing it through a filter zone containing filter material having a specific gravity of less than 1 or about 1 and a grain size of 6 mm. or less, the filter material is periodically cleaned by flushing it with water whilst agitating it with air under pressure and, if desired, mechanical means. The filter material may comprise plastics mixed with or coated on clay, kieselguhr, kaolin, chalk or slag and may be in the form of short cylinders, balls, lenticular elements or short tubes. In Fig. 3, during the purifying of waste liquid, the waste liquid is uniformly distributed over annular filter zone 10 by rotary distributor 13, aerating gas is supplied to zone 10 from pipe 5 via annular domeshaped chamber 2 and treated liquid is discharged through pipe 3. In the cleaning of the filter material, after filling the zone 10 with water, flushing water and air under pressure are introduced into zone 10 to circulate and agitate the filter material as shown in the R.H.S. of Fig. 3., to cause removal of sludge from the filter material, and sludge and flushing water are removed by pumps through oval grids 15<SP>1</SP>, pipe 17 and annular channel 18 to drain pipe 19 or through annular grids or conduits 15<SP>11</SP> to discharge pipe 16<SP>11</SP>. The filter zone may have a plurality of sludge removal grids in the form of perforated tubes 22 (Fig. 9) below which are aerating pipes 27. A suitable apparatus may comprise a plurality of filter zones positioned one above the other, side by side or in a ring formation. The filter zones may be provided with corridors for the operators. The filter zones may be cleaned separately. |
