Don't Throw Your Future Away with Plastic Packaging, Recycle It

Rising population and changing living standards in a globalising world are increasing production and consumption rates daily.

As production and consumption rates accelerate worldwide, the use of plastics that make our lives easier is also increasing. After use, plastics are generally abandoned in nature by people, leading to environmental problems. Today, most products discarded as waste are thrown away as people disregard their future. As a result, nature becomes polluted, ecosystems suffer damage, and unconscious behaviour deprives many living organisms of their right to exist. For this reason, particularly European countries are taking various steps to ban single-use plastics and bags. Despite such environmentally conscious approaches, it appears impossible for us to forgo the comfort that plastics bring to our lives. Instead, environmental problems can be prevented by implementing more environmentally friendly regulations in plastic use and production. As long as people do not give proper value to the environment and plastics, various environmental and economic problems will continue to arise despite all bans.

Of the 359 million tonnes of plastic produced globally, 150-200 million tonnes are released into the environment. This stems not from plastic itself but from people's habits after use. In recent years, Turkey has focused on recycling efforts, and source separation studies have been initiated with the Zero Waste project. Source separation of plastic increases the recycling rate while reducing recycling costs.

  Approximately 60 percent of plastic produced in Europe is used in packaging and consumer products. In Turkey, 37 percent of products used in the packaging sector consist of plastic packaging. Polyethylene terephthalate (PET), which is widely used in the packaging sector, is creating waste accumulation on a global scale. In Turkey, PET accounted for 23 percent of total plastic raw materials produced in 2019. Commercialised by DuPont in the 1950s, PET is a polymer widely used in many industrial applications such as fibres, foams, and films owing to its properties including low production cost, high gas barrier properties (against oxygen and carbon dioxide gases), heat resistance, and recyclability. Beginning to be used in bottle production in the 1970s, PET is the most recycled plastic packaging material in Europe. According to an OECD 2018 report, 970,000 tonnes of PET were recycled in the United States in 2014.

Figure 1. a) PET bottle waste abandoned in nature

b) Source separation of PET bottle waste

https://www.dw.com/en/adidas-nike-bolster-eco-claims-with-recycled-plastic/a-18406950 https://ec.europa.eu/research/infocentre/article_en.cfm?artid=50229

Although bio-based raw materials have been used in PET bottle production recently, recycling is widely recognised as the most effective method for reducing the environmental impact of PET. PET recycling has gained importance in minimising environmental problems and achieving sustainable production. PET bottle recycling work began in the 1970s initially to improve waste management. PET waste is classified as process waste and consumer waste. Process waste is generated from flash or production errors during the PET manufacturing stage. Consumer waste is considered waste generated after consumer use. PET waste is recycled using two main methods: chemical and mechanical.

PET, which is generally used in water, beverage and oil bottles in the packaging sector, is mechanically recycled after its waste is collected from the environment. In 2015, 0.51 million tonnes of 0.6 million PET waste were mechanically recycled in Japan. The mechanical recycling process consists of contaminant removal, shredding, washing, separation by density difference, drying and melt processing stages. During the contaminant removal stage, waste PET is separated from other plastic types, metal pieces and other materials. After this stage, PET waste is classified by colour, ground, and cleaned by washing. Following the washing stage, drying is applied to PET waste. Dried PET waste can be reprocessed and used in sectors such as packaging, automotive, textiles and furniture.

During reprocessing and "active life," PET is exposed to various factors such as mechanical forces, ageing reactions, acids and laundry detergents, which alter its structural and physical properties. This restricts the applications of recycled PET. To improve the structural and physical properties of recycled PET, different methods such as vacuum systems, solid-state polymerisation (SSP) and chain extension are preferred. The recycled PET raw material produced through these methods is used in place of virgin PET raw material.

Chemical recycling of waste PET is a highly costly method. In this method, depolymerisation of waste PET is carried out through chemical reactions such as pyrolysis, alcoholysis, hydrolysis, glycolysis and methanolysis. As a result of recycling, the chemicals obtained can be used in PET synthesis or in the synthesis of polymers such as alkyd resin, polyurethane, unsaturated polyester resin and epoxy resin. Through pyrolysis, PET waste is burnt for energy recovery. Since burning waste PET harms the environment, this method is not preferred much.

  Every recyclable waste product adds value to the economy as it can be used as a raw material. It should not be forgotten that PET bottle waste is not garbage but actually a raw material source. Recycling of PET waste enables more efficient use of resources and minimises the environmental impact of waste released to the environment. Although PET bottle waste is not substantial by weight, it represents a significant proportion by volume. For this reason, source separation of PET bottle waste, recycling and energy use are of great importance. Reducing PET waste released to the environment results in less raw material and semi-finished goods being used in production. Giving PET bottles a circular life will provide significant benefits to the country's economy in terms of raw material, energy efficiency and sustainable consumption.   References S. Devasahayam, G. B. Raju, C. M. Hussain, Utilization and recycling of end of life plastics for sustainable and clean industrial processes including the iron and steel industry, Materials Science for Energy Technologies 2 (2019) 634–646. Tournier, V., Topham, C.M., Gilles, A. et al. An engineered PET depolymerase to break down and recycle plastic bottles. Nature 580, 216–219 (2020). OECD, Improving Markets for Recycled Plastics: Trends, Prospects and Policy Responses, OECD Publishing, Paris, (2018). Turkey Plastics Sector Monitoring Report, PAGEV, (2019). https://sifiratik.gov.tr/plastik-atik