Chemical from plastic; trash-to-treasure mentality

WhatPackaging?’s weekly updates on the new developments in the field of sustainability.

11 Sep 2021 | By WhatPackaging? Team

A new scientific discovery offers hope

A team of Chinese scientists has converted a common type of plastic into useful materials using an inexpensive process, raising hopes that the method could be used to turn plastic waste into valuable products at a large scale. Using a catalyst made from common metals, researchers at Tsinghua University in Beijing have converted samples of PET plastic into commercially useful chemicals, along with hydrogen which can be used for fuel. In a paper published in Nature Communications, the team revealed the method can yield commodities worth USD 3,000 from one tonne of waste PET. That compares very favorably to a current market value for recycled PET of about USD 350-400 per tonne. The new process breaks PET plastic down into three useful substances: the first, called potassium diformate, or KDF, has commercial uses as a safe replacement for antibiotics as a growth promoter in animal feed; next, the process yields terephthalic acid, or PTA, which is used to make coatings and resins for metal components; lastly, the process yields a small amount of hydrogen, which can be used as a fuel.

A ‘trash-to-treasure' mentality can change plastic waste

Some scientists have called for a global treaty to end production of “virgin” plastic by 2040. Such an agreement would turbocharge the development of full circularity in the plastic chain, where everything is reused and nothing wasted and plastic material stays in a perpetual loop. Improved waste management, an optimised recycling system and clever product design can make recycling rates of 100% possible if all the moving parts work in unison. To adopt a fully integrated waste-to-product mindset, we need to communicate the value proposition to plastic manufacturers. There are clear financial benefits to this strategy as well as sustainability advantages. Using recycled content is not only about preventing waste; it also reduces CO2 emissions and energy use, allowing companies to meet ambitious corporate social responsibility (CSR) objectives and pre-empt government legislation on extended producer responsibility (EPR) and recycled content mandates. In addition, it lessens dependence on importing raw materials, shortening supply chains and reducing costs. Losing our virginity is a goal we must race towards. In a circular utopia, all plastics would be recycled back into the same products in a never-ending loop. Nothing would leak into the environment, nothing would downgrade and nothing would be made from fossil fuels ever again. However, even state-of-the-art facilities have systemic and technological limitations preventing them from attaining higher recycling rates. Technically, all plastics could be converted back into fuel through advanced chemical recycling methods, such as pyrolysis, but these are incredibly investment and energy-intensive and not feasible for small communities. Mechanical recycling may have its constraints when dealing with post-consumer waste, but what we can't convert back into the same product, we can still make into something else. Waste-to-product may be a line rather than a circle, but thankfully, it's a much longer line in terms of the life span and use of the material.

New bio-recycling routes for food packaging and plastic waste

The overarching objective of the RECOVER project is to demonstrate and upscale novel bio-based approaches to dealing with the problem of agri-food waste plastics (AWPs) and help to solve the problems of contamination of agricultural fields with non-biodegradable agroplastics and by providing sustainable management pathways for the non-recyclable packaging fraction of municipal waste management systems. To achieve these objectives, it is proposed to use innovative biotechnological solutions by combining microorganisms, novel microbial enzymes, earthworms and insects in order to biotransform non-recyclable plastic packaging waste streams and agricultural films. In addition, new raw materials for the primary sector biofertilisers and the bio-based industry (chitin and chitosan) will be produced as a result. The project charts the way for future exploitation and supports the EU’s efforts to shift to circular models and tackle plastic pollution. The RECOVER project pivots on a fresh concept where multiple species collaborate in an integrated and complementary way to either biotransform complex plastic mixtures into products or completely biodegrade and remove them. These biotechnological tools are: enzymes, developed using a synthetic biology approach; microbial consortia that attack mixed plastic waste under different environmental conditions; and insects and earthworms whose natural ability to ingest and digest plastics will be enhanced by reinforcing their natural microbiome with probiotics. These biotechnological processes will be developed in two scenarios: ex situ treatment in insect rearing chambers or compost reactors for non-recyclable plastics from municipal solid waste or agricultural plastic waste; and in situ treatment directly on soils contaminated with plastics, such as mulching films. The RECOVER project is a research and an innovative action that started on 1 June 2020 and will last four years.