Krofta Pressure Sand Filter (KPSF) is a cylindrical vessel containing a bed of fine sand or other granular media. The effluent flows downwards from the top of the vessel, percolating through the media and is drawn off at the bottom by the collector system.

Impurities such as suspended solids, silt, clay, organic matter and micro-organisms are filtered out by the media. Over time the collected impurities may cause choking in the media filtration, hence a backwash system using the clarified waste water is installed to maintain efficient filtration. The filtered effluent will contain less than 20 mg/L of suspended solids. KPSF is available as a sand filter, Dual Media Filter (KDMF) or Multi Grade Filter depending (KMGF) on the parameters and application.