Microplastics which are increasingly detected in aquatic environments constitute a global concern due to their persistence, mobility, and potential risks regarding water resources used to produce drinking water. This presentation aims to investigate the presence of microplastics in a conventional water treatment plant used in Geneva (CH) to provide tap water for 500’000 consumers.

Microplastic concentrations, size distributions, chemical compositions in raw and treated water and removal efficiency will be discussed as well the impact of the different water treatment processes. On the other hand, nanoplastics which are expected to result from the fragmentation of microplastics (probably the most hazardous fraction) will also be discussed. In particular, adsorption to mineral surfaces, considered as one of the most important processes controlling their fate and transport in conventional water filtration systems, will be presented by considering adsorption isotherms and kinetic models.

Adsorption mechanisms, influencing physicochemical parameters (pH, natural organic matter), and adsorption capacities
of the different porous media used in water treatment will be investigated using complementary techniques such as dynamic light scattering, laser Doppler velocimetry, scanning electron microscopy and turbidity measurements.