Flushing Device for Retention Tanks and Sewers

The self-contained GNA CSO HYDROSELF system has these main features:

  • The gate which holds back the stored water.
  • The float control mechanism for the gate, which is operated by a closed circuit hydraulic system.
  • The system may also be operated using electric controls, if desired, with power usage < 1.0 kW.

GNA CSO HYDROSELF may be used to flush waste water equalization tanks, CSO retention tanks or storm water run-off detention systems. After the water is drained from the tank, the flushing system is automatically activated thereby producing a high celerity wave. Accumulated debris and pollutants are washed from the tank floor and returned to the waste water treatment plant.

GNA CSO HYDROSELF may also be used in interceptors. Activating the flushing wave not only regularly flushes the interceptor system, thus increasing capacity, but it also reduces the pollutants concentration peak thus reducing the negative impact on waste water treatment plants.

The GNA CSO HYDROSELF flushing system keeps sewers clean.

Advantages of the GNA CSO HYDROSELF

  • No limitation on flushway length; several devices may be installed in series.
  • No external power required.
  • No external water supply required.
  • No maintenance required.

The Functioning

Highly polluted water flows through the prethrottle ➀ to the outlet. Inlet amounts larger than outlet amounts impound starting at the outlet. The floats ➅ are lifted and thus the flushing gates ➄ are locked by an encased, hydraulic transmission. Due to the prethrottle ➁, income water in the prechamber impounds more quickly than in the remaining retention system. By using backwater gates ➂ water flows early into the storage chamber ➃.

Thus a filling of the storage chamber is also guaranteed with a partial filling of the retention system. After each filling – even after partial filling – the flushing gates are unlocked by the falling floats with a lowest water level. This takes place subsequently, as the flushing sump shall remain as small as possible and the pollutants shall not be flushed all together. If the prethrottle is closed, it is possible to flush manually. A single flushing wave is sufficient to flush reliably long tanks and channels even with low storage chambers.

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