Abstract
The performances of in situ turbidity meters that are widely used in monitoring turbid water were compared. Five commercially available models of different measurement systems were calibrated with the turbidity standard material, and the performances of the instruments were investigated with various test waters.
When the turbidity-causing material is mainly inorganic suspended particles, all tested models of different measurement systems were adaptable to the measurement. However, the models of the back scattering system and side scattering system were strongly affected by the particle size distribution of suspended particles. Thus, it was necessary to prepare calibration curves for the expected turbidity of suspended particles. When the turbidity-causing material contains organic particles in addition to inorganic particles, precise measurements could be achieved with the models of the integrating sphere system or beam attenuation system.
