Overflow events within a sewer system can pollute receiving waters with floatables and suspended solids, for example plastics, papers, sanitary articles. This is evidence of insufficient cleaning of the combined sewage at CSO´s.
For discharging stormwater, combined water and sewage – in line with modern principles of water management – throttling units with a perpendicular discharge curve are applied which have constant discharge limitations regardless of impounding heights in tanks, backwater channels, surplusing works, sewage treatment plants and settlers.
During heavy rains overflow spills from combined water canals carry considerable quantities of floating solids and suspended matter into our waters. Do you know the last high water level of your waters? You recognise it from the ‘toilet-paper line’ and the debris left behind, such as paper, synthetic materials and hygiene articles in the vegetation on the river banks.
Deposition of grit and assorted debris occurs within both foul and surface water systems, provides frequent problems for maintenance teams.
The HydroSelf flushing system uses detained water to flush tanks with an extremely high efficiency.
Even when CSO’s and SSO’s are equipped with scum boards, considerable quantities of floatables and suspended solids still reach the waters. Sanitary articles, toilette paper and synthetics are left caught in the river bank after heavy rain. The waters are biologically and hydraulically “stressed”.
Because of tight budgets in municipalities and cities, cost-effective wastewater treatment is in demand. Tanks are improved through optimal inflow in sedimentation and reduced by activating canal volume. Through de-sealing and infiltration of unpolluted surface water the tanks can be even further reduced.
Measures to protect waters are necessary but often expensive. Legislation demands storage basins for the protection of receiving waters like streams, rivers and lakes. Because of the huge investment costs involved, municipalities are seldom able to build such structures. Action is also called for when the canals in an urban area are overburdened due to new development areas.
Worldwide flooding in recent years proves the need for ongoing protection. The usual flood protection measures are dikes, walls and protection barriers. Today these are often washed over in heavy rain. Stationary flood protection is expensive and time- intensive. Up to now, the sandbag has been the most important defence weapon. Technical relief agencies and municipal authorities have reached the limits of what they can do.