External Influences Affecting the Hydraulics of Automatic Siphons for Vertically Flowing Filters

Abstract

In recent years, natural wastewater treatment wetland plants have been gaining more attention from researchers and the public due to their low operating costs and efficient way of treating wastewater. Treatment wetland plants with pulse-fed vertical flow filters are one of the most efficient treatment technologies. For optimum operation, intermittent loading of wastewater onto the filter surface is necessary, for which various types of automatic siphons can be used in addition to pumps. This kind of automatic siphons do not require electricity for their operation. The aim of the actual measurements was to specify the hydraulic characteristics of four different types of automatic siphons used in France, Germany, and the Czech Republic. In the course of the laboratory measurements, it was possible to define the basic hydraulic characteristics of the different technical solutions - e.g. maximum water flow, starting and shut-off water level, emptying rate and discharge flow. The measured values then lead to the determination of the total hydraulic losses of the device, while the limits and nature of the individual solutions are shown in comparison with each other. The results can be used for the design of the downstream hydraulic system of the distribution piping that is spread over the filter surface.