At a lower flow-rate, grains smaller than 0.1 mm settle and non-dissolved organic matter is deposited, while at a high flow-rate there is an undesirable washout of particles smaller than 0.1 mm to the sedimentation tank, along with organic sediment.

The new flow area regulator, designed as a technical solution for horizontal sand catchers, solves the aforementioned problems presented by the currently used equipment. Its advantages over current imperfect solutions primarily include ensuring that waste water is guided through a horizontal sand catcher more safely, trapping the lower part of organic materials in the settled mixture, trapping considerably smaller sand particles even during storm water flow-rates and the follow-up elimination of operational problems in the sedimentation tank, also during its excavation, or the application of the stabilized sediment to biological waste water treatment plants.

In practice, the equipment works by complementing the series of horizontal slot sand catchers with a simple element which automatically regulates the overflow surface in the sand catcher outlet according to the volume of inflowing waste water. Thus a smooth change in flow is ensured and so is the subsequent regulation of the delay time, i.e. the time needed for the selected sand grains to settle.

Currently, this equipment from the workshop led by Ing. Michal Kriška, Ph.D. of the Institute of Landscape Water Management is protected as a utility model, and several designers and operators of cleaning facilities have already expressed their interest in it.

Ing. Michal Kriška, Ph.D. graduated in landscape water management at the Faculty of Civil Engineering, BUT. Since 2007 he has been an employee of the Institute of Landscape Water Management, where he currently works as a lecturer specializing in vegetation root treatment plants, ground filters, waste water cleaning using extensive technologies and wetland systems.