A Simplified Experimental Method to Estimate the Transport of Non-Buoyant Plastic Particles Due to Waves by 2D Image Processing

Plastic is one of the most widely used materials. It is expected that there will be about 12 billion tons of debris dispersed into the environment by 2050. This, combined with marine littering, pollution and climate change will threaten our ability to sustainably use oceans, seas and coasts. In this regard, it is important to understand transport mechanisms and predict hotspots of plastic pollution. Physical models are a valid support to achieve such a goal. In this regard, it is necessary to adopt specific techniques which allow the movement of plastic to be monitored. Considering the relatively high size of plastic particles that could be used during experimental campaigns, new approaches based on image processing could be implemented. This study presents a simplified method to estimate the transport of particle debris under sea waves by 2D image processing, avoiding any disturbance of the dynamic field. The proposed method, based on the blob analysis, was implemented and calibrated within the wave flume of the Hydraulics Laboratory at the University of Messina. After a calibration process, the method was used to study the behaviour of the plastic debris under several hydrodynamic conditions. The results obtained in terms of displacement and velocity of the analysed sample showed a great reliability of the used methodology.