Verfahren und Vorrichtung zur Reinigung von Regen- und/oder Mischwasser

EP 978483 A UPAB: 20000313 NOVELTY - Water contaminated with solids is taken from a drain system (7) or storm tank. Coarse filtration (2) removes solids in the millimeter size range and is followed by microfiltration (5) separating suspended solids. Separated solids and retentate reach a waste water treatment plant via the drains. Purified water is introduced into open natural waters, or is run off as surface water. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for the corresponding treatment plant. Preferred features: The water is supplied under pressure to solids separation, where particles of 0.5-3 mm are removed. Before or during supply to the coarse separation stage of the microfiltration plant, turbulent flow induced, preventing floated solids layering on the filter. During microfiltration, solids with an effective diameter of 0.5-100 mu m are separated. Pre-purified water from the coarse solids separation stage is supplied to a buffer tank (3), where sedimentation takes place, and from which it is supplied to microfiltration. Retentate containing suspended matter from microfiltration, is bypassed (8) to the buffer. Pumps (1, 4) or height difference generate the pressures required. USE - To purify rainwater from drains, or mixed water, i.e. communal sewage and rainwater, sufficiently for discharge to natural waters. ADVANTAGE - The process achieves considerable reduction in solids. In addition, chemical components and pathogens are reduced. 70% of material which can be filtered is removed, reducing COD and/or BOD (depending on content) by 30% or more