The digital Turbidity sensor VisoTurb® for the IQ SENSOR NET from WTW is ideal to monitor turbidity in the outlet of a wastewater treatment plant. The unique integrated ultrasonic cleaning system ensures low-maintenance and continuously reliable measuring. With the nephelometric measuring principle of the VisoTurb®, the stray light is measured at a 90° angle. The measuring setup is suitable for low and medium turbidity values up to 4000 FNU. According to DIN EN 27027 and ISO 7027, infrared light is used in the wavelength range of 860 nm. This wave length is outside the visible range, so that possible sample colorings generally do not cause any interference.