The WWTP of the Bavarian town Hundersdorf is presently extended to serve a total population of 5,500. The main sewer connecting the town to the plant is DN 1,400 and has an average slope of only 0.15 %. The average flow of 35 l/s is much too low for sewer flushing. As a result grit accumulated in the sewer and formed heavy deposits. Frequent manual flushing of the sewer was necessary, which was very laborious and costly.

In 2006 an automated HUBER PowerFlush® gate was installed to solve this problem. The swivelling flap gate is installed near the up-stream end of the main sewer section. While the gate is closed, wastewater collects upstream of the gate. When a certain upstream water level is reached, the gate automatically opens and a water surge rushes through the downstream sewer and flushes it out.

The plant operators are very happy with the results. Once per day they press a button to close the gate. The following water retaining and flushing process is fully automated. Since the system is in operation, the grit arrives at the plant, is removed in its grit channel and washed in our ROTAMAT® COANDA grit washer RoSF 4. The clean grit is reused as construction material. Manual flushing of the main sewer is no longer needed, so that the operators save much time and costs.

By Helmut Schmidt, HUBER Sales Office Southern Bavaria