Control of Surface Plastic Transport in Natural Streams

In the aftermath of the worldwide severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic, the disposal of plastic and nonwoven fabric materials originating from personal protective equipment (PPE) into freshwater bodies like lakes and rivers has significantly increased. Surface plastic transport and accumulation have become a relevant source of pollution that adversely affects the quality of water and fluvial ecosystems. Although attempts have been made in the past to study the flow characteristics of plastic at the river surface, an in-depth study of structural configurations that can act as potential plastic traps, facilitating reduction of pollution due to plastic transport, is necessary. This paper investigated the hydrodynamics of surface plastic transport in the presence of several control structures. In addition, useful empirical equations were derived to predict the kinematic and trapping efficiency of the mentioned structures, valid for both straight and curved channels under a variety of hydraulic and geometric conditions. It was found that the Froude number and position of the structure play a dominant role in influencing surface plastic transport mechanism and the overall efficiency of structures in limiting plastic transported downstream.