UF-TEC is a filtration system which allows sample feeding of COLOR TEC or similar analyzers. It consists of a control panel and an immersion filtering element that can be installed in any section of a water treatment plant because its operation is independent of the sample condition: biological sludge, presence of foams, algae, bloated or floating sludge. Suction of the sample occurs using the peristaltic pump located inside the control panel, which is also used to push the filtered liquid to the analyzer. Start of the peristaltic pump and duration of suction is controlled by the COLOR TEC analyzer in relation to the predetermined frequency of analysis and the distance between analyzer and the sampling point. A cleaning system is provided, controlled by the analyzer or through a timer (optional), which by means of a compressor and a 3-way valve directs, on the same sampling tube, pressurized air which allows to purge both the line and the pipes of the filtering element.