| 摘要 |
Trickle filters having a packing of rock chips serve for biological waste water treatment and, when they are designed and charged according to known guidelines, have a so-called self-cleaning capacity, which permits the continuous operation required in sewage treatment plants. However, owing to natural weathering of the stone chips, and also owing to the fine sands carried by the waste water, after a relatively long operating time, deposits occur in the packing which greatly reduce the permeability and thus lead to a reduction in the purification efficiency. As an effective, but also highly expensive method for recovering the permeability, the occasionally practised emptying of the packing, batchwise washing and refilling of the trickle filters can be considered. The invention proposes, by means of the stationary installation of perforated or slotted washing tubes, which are introduced vertically into the packing and are connected to a washing water supply, to wash the packing over the entire filling depth and within a defined region of action in such a manner that all the deposits present in the interstitial spaces between the chips packing are washed out. |
