Anticipating higher drainage fees has prompted Danish waterworks to investigate more economic solutions than flushing rinse water down the drain. For the Ulfborg waterworks, this requires producing 60 cubic metres of potable water per hour - a large amount of water simply for backwash. Calculations revealed that installing a separate pressure filter plant for cleaning the backwash water from the sedimentation tank would be profitable in just a few years.

All the rinse water is now reused and the waterworks does not pay any drainage fees at all. Furthermore, as the plant is a closed circuit, the raw water consumption has been reduced. An UV disinfection plant is installed as extra security against contamination and bacteriological growth in the sedimentation tank.