MEASUREMENT OF MUD FLOC-SETTLING VELOCITY USING A LASER DIFFRACTION PARTICLE SIZE DISTRIBUTION ANALYZER

In-situ and laboratory measurements of particle setting velocity through different techniques, such as settling tubes and video systems, suffer from human and random sampling errors and lack of accuracy. The development of a method to improve the accuracy of the settling velocity measurements has been a challenge for researchers. We propose a method using a laser diffraction particle size distribution analyzer (Shimadzu, SALD-2000J) to estimate the particle settling velocity with increased accuracy. SALD-2000J measures continuously the average intensity of light scattered and the particle size distribution of mud flocs, which were used to estimate the particle settling velocities. The SALD-2000J method produced high accurate results saving both labor and time. The predicted settling velocity presented the same order of magnitude of those reported in previous studies. The settling velocity was used in the simulation of particle size distribution variation, producing a relative error of particle size distributions (obtained from SALD-2000J and the simulation) interior to 5%. The results suggested that the proposed method can be applied to the prediction of settling velocities of mud flocs and inorganic particles both in fresh and saline water environments.