| 摘要 |
<p>Packing for the trickling filter units of a biological sewage treatment consists of many interconnected strips of plastic materials, esp. polyethylene or polypropylene foils. The strips hang down on both sides of carrier beams, e.g., in three layers of strips, arranged with an offset of half a pitch from each other. Another foil along the carrier beam holds the three layers in place.</p> |
