Pipe for transporting water to be made potable has inner coating with rough surface to create biofilm that removes pollutants

摘要

The pipe (26) for transporting water from an untreated source (4) via a treatment unit (14) that renders it potable to a consumer outlet (6) has a rough-surfaced inner coating to retain a biofilm that removes pollutants, especially nitrates. The arithmetical mean of the inner surface roughness is between 0.10 and 0.30 mm, and preferably between 0.175 and 0.225 mm. The inner coating is made from a different material to the pipe, and can be of an aluminous mortar containing grains of sand or blast furnace cement mortar; it is applied to at least one section of the overall pipeline (12) taking the water from the untreated source to the treatment plant. An intermediate unit (10) delivers nutrients, such as ethanol or an ascorbic acid solution, into the pipeline through a regulating valve from a reservoir (20) to promote the creation of the biofilm, and the treatment plant incorporates a filter (40) to remove the products of the biofilm.