The PR-10 hydrocyclonic element is designed and patented construction and installation for removing those extremely fine solid particles, which density is heavier than the liquid, from any liquid or mixture with gas. For example, produced water, sea-water, etc. The flow enters from the top of vessel and then into the “candle”, which is consisted of varies number of discs in which the PR-10 cyclonic element are installed. The stream with solids are then flows into the PR-10 and the solid particles is separated from the stream. The separated clean liquid is rejected into the up vessel chamber and routed into the outlet nozzle, while the solid particles are dropped into the lower solids chamber for accumulating, located in the bottom for disposal in batch operation via the sand withdraw device ((SWDTM series).