Abstract: A plastic contact material is disclosed for the treatment of a liquid, comprising a plurality of strips made of a plastic material and wherein each of the strips has at least one tension element. A process is also disclosed for manufacturing a biological water treatment contact material made of a plurality of strips of a plastics material, which process comprises providing at least one strand at an elevated temperature, and applying the strand to a strip of plastic material while the strand is still at said elevated temperature.

Abstract: A plastic contact material is disclosed for the treatment of a liquid, comprising a plurality of strips made of a plastic material and wherein each of the strips has at least one tension element. A process is also disclosed for manufacturing a biological water treatment contact material made of a plurality of strips of a plastics material, which process comprises providing at least one strand at an elevated temperature, and applying the strand to a strip of plastic material while the strand is still at said elevated temperature.

Abstract: Known types of equipment for the biological denitrification of potable water require (back) washing of the reactors from time to time. These denitrification processes proceed therefore in a discontinuous manner. The invention proposes a continuously operating denitrification process with a simple equipment arrangement. This is achieved by sumberged drum reactors (12, 14) which rotate in a first, anoxic biological stage (10) and in a second, aerobic biological stage (13). The immersion bodies (immersion body segments 31) contained in these reactors are, due to the rotation, continuously washed during the treatment of the potable water. Moreover, the sumberged drum reactors (12, 14) of the two biological stages (10, 13) are arranged according to the invention on a common drive shaft (26) with a drive element (drive motor 27).

Abstract: A packing element having a cylindrical outer cover (11) with at least one guiding surface (16, 20, 21) of holohedral construction and dividing the outer cover (11) into several subspaces (19). The outer cover (11) has web ribs (12), running in the longitudinal direction of the cover, and annular ribs (13), running perpendicularly to the web ribs, thus forming approximately square net openings (14).

Abstract: Known types of equipment for the biological denitrification of potable water require (back) washing of the reactors from time to time. These denitrification processes proceed therefore in a discontinuous manner. The invention proposes a continuously operating denitrification process with a simple equipment arrangement. This is achieved by submerged drum reactors (12, 14) which rotate in a first, anoxic biological stage (10) and in a second, aerobic biological stage (13). The immersion bodies (immersion body segments 31) contained in these reactors are, due to the rotation, continuously washed during the treatment of the potable water. Moreover, the submerged drum reactors (12, 14) of the two biological stages (10, 13) are arranged according to the invention on a common drive shaft (26) with a drive element (drive motor 27).