Plastic as marine debris and its potential for economic value: A practical and analytical estimation of the marine debris characteristics and a comparative evaluation of possible treatment procedures
Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
Every year around 270 million tonnes of plastic are produced worldwide. As a result of poor waste management in many countries, a large amount of it ends up in the world’s oceans where it degrades into micro particles. The degrading plastic particles release toxic chemicals, which can bioaccumulate in bodies of oceanic life and subsequently travel through the nutrition chain. Hence it is of great importance to find solutions to this problem. In this report, the composition and scale of plastic marine debris is investigated using data collected from fieldwork performed by the authors in a number of countries around the world, as well as through examining and combining reports from the International Coastal Cleanups organized by Ocean Conservancy. The combined data is used to create a top ten ranking of the most common plastic marine debris and its corresponding plastic type. The most common items were determined to be e.g. beverage bottles and plastic bags and the most common plastic type was estimated to be PP, LDPE and PET. According to the data collected through the fieldwork, the total plastic share of the marine debris was estimated to range between 67.4% and 86.3%. Further, the possible economic gains of conventional material recycling, incineration for energy recovery and microwave pyrolysis as a material recovery process are investigated. The study is executed partly by reviewing several scientific articles on the subject as well as by practical laboratory work with microwave pyrolysis of polystyrene. The study shows that conventional recycling is not a sufficient treatment, due to the photo degradation of the polymers in the oceans. Furthermore, end products from incineration give a greater economical gain and provide for a less complicated and time-consuming procedure than microwave pyrolysis when considering the composition of plastic marine debris. However, microwave pyrolysis is a more environmentally friendly option than incineration due to the greenhouse gas emissions caused by incineration.
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IdentifiersURN: urn:nbn:se:kth:diva-149946OAI: oai:DiVA.org:kth-149946DiVA: diva2:741676