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Stormwater treatment with flow separation

Stormwater treatment with flow separation

For the sustainable protection of waterbodies, FRÄNKISCHE use the flow separation principle in their stormwater treatment systems of the SediPipe family: The patented flow separator technology efficiently cleans stormwater from dirt and pollutants. The slightly inclined, stretched sedimentation chamber with flow separator safely retains solids. An optional second grid provided in the upper pipe section separates oil and light liquids.

Hazardous substances in stormwater pollute the groundwater and surface water; coarse solids like dirt, mud, and sand may clog the storage/infiltration systems: To avoid this, sedimentation systems clean stormwater. Storm and heavy rain keep on remobilising the settled sediment in large-dimensioned stormwater sedimentation tanks, concrete tanks or large pipes and re-entrain them. Giving the water less space in the collection medium is the better solution.

Small pipe diameter with optimised flow rate

This is the reason why FRÄNKISCHE Rohrwerke use a sedimentation pipe DN 600 with flow separator designed at a defined angle of ascent between the start and the target shafts of their stormwater treatment systems. A green grid in the lower pipe section ensures as a flow separator the controlled and efficient water inflow – virtually without any partial flows. The particles deposited downstream of the grid accumulate in the area with little water movement in the lower pipe section and are not remobilised during rainfalls. This way the naturally cleaned stormwater can be returned to the receiving waters or groundwater. “FRÄNKISCHE’s patented flow separation technology provides controlled flow harmonisation during the flow process so that solids can deposit more efficiently – and this on a sustained basis” says Michael Schütz, head of FRÄNKISCHE’s Drainage Systems Product Management.

Technology applied in many system variants

FRÄNKISCHE use their flow separation in the tubular SediPipe level stormwater treatment systems – the systems with inlet and outlet on the same level, SediPipe basic with twelve metres maximum length, the SediPipeL modular system as well as SediPipe XL for large areas. The stormwater experts furthermore use the sophisticated technology together with an additional substrate filter unit in the target shaft of their SediSubstrator basic, SediSubstrator L and SediSubstrator XL treatment systems. The SediPipe L plus and XL systems even have two flow separators to clean the water; the grid at the bottom of the pipe is responsible for sedimentation, the upper one additionally separates oil and light liquids. FRÄNKISCHE also implements the flow separator technology within the little space of the point-shaped SediPoint treatment shaft using a sediment collector with spiral water flow.

The SediPipe pipes with integrated flow separator produce a controlled flow and achieve optimum treatment results. FRÄNKISCHE’s flow separation principle prevents sediments from remobilising in case of heavy rain and lets them deposit more efficiently.

For detailed information and product descriptions, please refer to and