Development Of A Low-Maintenance Turbidimeter

By Lukas Staub

State-of-the-art turbidity meters for potable water analysis are based on the nephelometric measurement principle as described in Standard Methods and adopted by the ISO standards. Turbidity is determined by the measurement of light, scattered at an angle of 90° to the incident beam.

Readings are obtained from a calibration curve established with a primary standard (i.e., Formazine). Results are expressed in FNU (Formazine Nephelometric Units) or NTU (Nephelometric Turbidity Units). A ratio turbidity meter measures the ratio between scattered and transmitted light. If just the transmitted light is detected, it is a single beam turbidity meter. The set-up of the latter two is quite simple, but there are some disadvantages, especially in terms of maintenance.

In developing the design of the new SWAN Turbiwell turbidity meter, the focus was on achieving a low-maintenance apparatus.