| 摘要 |
In the removal of suspended solids from a liquid by (a) flowing the liquid through a filter bed of discontinuous polyurethane particles in a filtration vessel and discharging solids depleted liquid from the vessel, the filter bed being at least partially loaded with deposited solids, (b) terminating the liquid flow and (c) renewing the filter bed by removing the deposited solids, the improvement comprises that the regeneration step (c) is carried out by adding >=1 bed volume of regeneration liquid (I) to the vessel and mechanically mixing the filter bed in (I) and hold-up liquid resulting from termination of liq. flow to disengage the deposited solids from the polyurethane particles. Solids-enriched liquid is then discharged from the filtration vessel. Only a very low volume of (I) is required. Liquid to be treated may be effluent contg. 40-60 ppm suspended solids, river water, water for use in boilers, or a stream from an algae pond (oxidation ditch). |
