Recycling of Marine Plastic Waste

Currently recycling of collected marine plastic debris (MPD) is a huge challenge because of three major reasons. First, large-scale collection logistics are to date not sufficiently developed because marine plastics are dispersed over a large area. Second, MPD is very diverse and strongly associated with manifold other unwanted natural and human-made contaminants, which poses a challenge to sorting and recycling. Third, this type of plastic waste is often characterized by compromised physical and mechanical properties, as a consequence of environmental degradation processes that occur in the marine environment. This chapter aims to provide a background on present-day MPD classes, polymer types, accumulation pathways, and prevailing waste management routes. Further, we identify degradation and contamination as material challenges to recycling. To this aim, a brief description of the different degradation processes occurring in the marine environment and issues of chemical contamination is provided. In view of the latter, MPD mechanical and chemical recycling studies and initiatives are discussed. Finally, the current commercial developments to recycle MPD and to incorporate these within the framework of a circular economy in form of new “eco-products” are discussed. Unfortunately, this work shows that in many cases the public is not correctly informed about the type, quantity, and sourcing location of what is termed “ocean plastic” used in new products. We thus highlight the importance of transparency in eco-product marketing to build consumer trust and credibility.