On the prediction of settling velocity for plastic particles of different shapes

Transport processes of plastic particles in freshwater and marine environments are one of the relevant advances of knowledge in predicting the fate of plastic in the environment. Here, we investigated the effect of different shapes on the settling velocity, finding a representative reference diameter which encompasses threedimensional shapes like pellets or spherules, two-dimensional shapes like fragments or disks, and onedimensional shapes like filaments or fibers. The new method is able to predict the settling velocity of plastic and natural particles given the representative size and the Corey shape factor coefficient, over the entire range of viscous to turbulent flow regime. The calibration of the method with experimental data, and the validation with an independent dataset, support its application in a wide range of hydraulic conditions.

Automated summary

The transport processes of plastic particles in freshwater and marine environments are important for predicting the fate of plastic in the environment. By studying the effect of different shapes on settling velocity, a new method was developed to predict the settling velocity of plastic and natural particles across a range of flow regimes. Calibration and validation with experimental data support the application of this method in various hydraulic conditions.