A sewer system usually has large amounts of unused storage capacity since it was designed to cope with peak flows. The HydroStyx^® discharge brake allows this hidden capital to be utilized. During heavy rain, the HydroStyx^® discharge brake allows the free sewer volume to be used as storage. The flow in the trunk sewer is regulated to enable unused volume to be used as attenuation. Hydro-Styx^® discharge brakes are installed within chambers along the length of the sewer to form a cascade. A calculated Pass Forward Flow (PFF) is allowed to flow down the sewer section. When the storm flow rate increases, the brake causes the flow to surcharge upstream. The debris in the water sink and are transported to the treatment plant. As the storage volume is used, the combined water flows over the crest of the brakes and the sewer regains full capacity. The retained water contains fewer pollutants, the discharge hydrograph shows that the storm peaks are attenuated reducing the downstream flood risk. Expensive sewer enlargement or attenuation tank provision may not be necessary as the existing sewer volume can now be mobilised.

The design of the HydroStyx^® discharge brake requires qualified engineering calculations of the sewer network. We can recommend useful software and supply you with competent personnel.