Wax worms to fight waste; sand from plastic

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

14 Aug 2021 | By WhatPackaging? Team

Wax worms can help fight plastic waste

A novel solution to ease the crisis of polyethylene might lie in wax worms. In a chance discovery, scientist Frederica Bertocchini found that these worms created holes in a plastic bag. To develop her finding, she teamed up with scientists from the University of Cambridge and confirmed, through several experiments, that the worms are able to break down the chemical bonds of PE. By itself, PE takes hundreds of years to decompose depending on its form and use. In a study, scientists found that 100 wax worms were able to biodegrade 92 milligrams of PE in 12 hours, or about 2.2 holes per hour per worm. The answer lies in the worm’s physiology. Wax moths lay their eggs within beehives to allow the wax worms to feed on beeswax for nutrients. Both PE and beeswax are polymers consisting of similar chemical bonds. The worms’ ability to break down beeswax is thought to be similar to that of their ability to break down plastic.

In a recent study by the Pondicherry University, researchers found similar results in a smaller species of wax worm, with a biodegradation rate of 2.01 holes per hour in PE film. One key element in this study compared the survival rates between wax worms feeding on only PE and those on traditional wax worm diets. Worms that were on wax comb diets had a 92% survival rate, whereas wax worms on a PE diet had an 80% survival rate.

Using plastic waste to help solve sand shortages

To try to reduce the need for sand, a small but growing number of researchers are turning to technology and innovation in the hunt for alternatives. These include Dr John Orr, a lecturer in concrete structures at Cambridge University. His research has found that plastic waste can be sorted, cleaned, shredded and crushed into a sand alternative for use in concrete. He has looked specifically at the potential impact of the solution in India. Here the cost of sand has skyrocketed - while at the same time estimates suggest that 15,000 tonnes of plastic waste is dumped every day in the country. “We found that you can replace up to 10% of the sand in concrete with the plastic, and it has the same strength and the same longevity," said Dr Orr. Unlike sand, plastic won't stick to the cement paste around it, so it can only replace 10% of the raw material, he says. “But that still saves the need for a huge amount of sand, and helps to reduce the vast amount of plastic waste on India's streets. From a cost perspective, using plastic can be cheaper, broadly speaking, especially as sand goes up in price as it becomes scarce.” Dr Orr reckons that if using plastic in making concrete were adopted across India it could save 820-m tonnes of sand a year. At the same time, other research is being done into using other waste materials in concrete in place of sand, such as shredded old car tyres or ground-down glass.

Using blockchain to ensure traceability in plastic waste streams

Circulor has announced a partnership with energy company TotalEnergies and Recycling Technologies, a chemical recycler of plastic, to develop a blockchain-enabled traceability solution for hard-to-recycle plastics (HTRP). Project Trackcycle will embed blockchain technology into the advanced recycling value chain, with the aim of providing a fully traceable and accurately labelled record of recycled materials, from waste sourcing up to the use of recycled polymers in new production streams. According to the companies, this will provide stakeholders in the polymers industry with visibility of the provenance and quality of the materials entering and exiting their facilities. As part of the Trackcycle project, TotalEnergies and Recycling Technologies teams plan to leverage their industrial and R&D expertise to improve the traceability of feedstock from post-consumer plastic wastes used in the production of recycled polymers. The consortium will work closely with several plastic waste suppliers, including a multinational FMCG company that provides post-industrial waste.

DTU develops sustainability throughout the campus

The development of sustainability on campus of the Technical University of Denmark (DTU) will become more visible in 2021 with the expansion of indoor waste sorting into 12 fractions and a digital recycling exchange on which the departments can exchange materials. However, the biggest sustainability contributions will be in the form of a reduction of DTU’s energy consumption and on the procurement side, where — in future — materials and products for construction and operation of campus will be assessed in a life cycle perspective. The new waste sorting solution is one of many priority areas in DTU’s sustainability policy, which has been developed in continuation of DTU’s strategy for 2020-2025: Technology for people, where sustainability is one of three objectives. The policy sets out how DTU will contribute — in words and actions — to a sustainable transformation of society, and how DTU works internally with sustainability in the University’s research and academic activities, management, and overall culture.