Recycling of Marine Litter and Ocean Plastics: A Vital Sustainable Solution for Increasing Ecology and Health Problem

Abstract

Marine litter is a crucial health and environmental issue in the global sense for not only humankind but also for cetaceans, marine life, and other flying and land animals. It is known that marine litter has significant environmental, economic, health, and aesthetic effects. Marine litter is a permanent, manufactured, or processed solid material which is discarded, disposed, or abandoned from any source into marine and coastal environments. It can be composed of the wastes and particles of abandoned waste textile products, synthetic garments and their fragments, fishing nets, fishing lines, industrial product wastes and industrial plastic production wastes such as plastic bottles and plastic containers (mostly made from synthetic polymers), vehicle tire dusts, and breakdown of litter and cosmetic products. In most cases, plastics are one of the most important components of marine litter because of their very slow decay rates. It is stated that approximately 90% of the marine litter is composed of plastic material wastes and 5–13 million tonnes of plastic waste litter are released to the marine-related environment per year. The amount of plastic waste in the seas is likely to continue to increase, mainly due to the negative increase in plastic consumption (about 9% per annum) and the inadequacy of its reuse, recycling, and waste management practices. The entanglement and ingestion of marine litter directly damage wild animals and their environment. Accumulation of marine litter on the seabed, accumulation of trash, and seagrass deposits in coral reefs cause damage to the natural habitat and damage the ecosystem. Plastic entanglement and ingestion problems by the animals are the main issues with macroplastics. On the other hand, plastic ingestion and accumulation problems by the animals are the main issues with microplastics. Microplastics in marine litter can be generated through microbeads, pellets, abrasion of especially car tires, textile materials and textile products, the decay of mesoplastics and macroplastics, and so on. Microfibers and microfibrils, which may be generated during ordinary home laundry cycles due to the agitation and beating nature of the washing process and end up in sewage, are also a subcategory of microplastics. Ingestion of microplastic and microparticle marine litter can cause many health problems. Microplastics in the sea enter the body of living sea creatures. As a result of these marine organisms, such as fishes, being consumed by humans, these microplastics and their remnants enter the human body and cause further health problems. Plastic materials enter to the seas and oceans end up on ocean floor, sea sides, beaches, and ocean surfaces. Unfortunately, degradation of these plastic waste litters in the marine environment needs centuries. Various measures are taken to remove the plastic wastes from the seas and seashores. Coastal cleaning activities and cleaning nets taken to the coasts are some of the most commonly used methods. The most common approaches for collected marine litter can also be storage or incineration. However, these methods may not be always ideal solutions because of limited storage space and pollution risks. The most likely solution for the destruction of plastic marine litter is the plastic recycling technologies commonly used in the processing of industrial wastes. The waste plastic and plastic parts collected from the seas and seashores are separated from each other by various methods and then each type of the recovered polymer, such as polyethylene terephthalate (PET) polymer, polypropylene (PP) polymer, and polyamide (PA) polymer, can be included in the recycling processes at their relevant recycling facilities. Plastic recycling technologies can typically be classified in three ways: mechanical recycling, chemical recycling, and thermal recycling. In this chapter, marine litter and recycling of marine litter and ocean plastics are comprehensively reviewed. First of all, the information regarding marine litter sources, marine litter types, and the contribution of synthetic fibers to marine litter via laundry (washing) cycles is given. Then, the ecological and socioeconomic effects of marine litter are discussed. Afterward, the precautions against marine litter and recycling of marine litter (mechanical recycling, chemical recycling, and thermal recycling) are mentioned. Finally, the recent commercial developments for marine litter recycling are covered.