VALIDATION OF POROUS CONSTRUCTIONS OF FILTER STRUCTURES

Rapid filters are important in technological schemes for purifying natural waters. They provide the required water quality, useful capacity of water treatment plants, as well as required technical and economic value. One of the main structural elements of filters is the wash water drainage system. The authors outlined the basic requirements for diverter systems, namely, uniform collection of wash water from the filter area and prevention of entrainment of the filter medium during washing. The article discusses two design options that fully meet these requirements: horizontal gutters with inclined meshes on their upper edges and porous polymer concrete pipes. The article provides data indicating that inclined grids and porous polymer concrete prevent grains of filter medium with a size of 0.5 mm from penetrating. Such medium is most commonly encountered in filtration structures of domestic drinking water supply systems. An experimental comparison of porous and mesh devices in systems for removing wash water from rapid filters was carried out by comparing their relative coefficients of hydraulic resistance. It has been established that the coefficients of hydraulic resistance of polymer concrete and mesh initially increase with further stabilization. At the same time, their maximum relative values differ significantly from each other: coefficients of hydraulic resistance for polymer concrete = 5.4; for mesh = 2110. The result of the conducted experiments shows that the head loss in polymer concrete during filtration under conditions of suspended medium is approximately four times lower than in the mesh due to the clogging of mesh cells with sand particles, confirming the advantages of porous polymer concrete.