Session 4: Poster abstracts

Circular economy

Manuela Benavides – (1) QUT Centre for a Waste Free World
Plastic futures: speculative design for a true circular economy

The Circular Economy (CE) has been internationally elevated as a major pathway to tackle the plastics waste crisis and distancing the economy from perpetual growth of resource extraction. At the very heart of the CE is a need to move away from capitalist growth models, an overhaul of our ways of production and consumption, and a shift of focus from economic growth to social justice and wellbeing. However, government policy and industry reports display a conflation in discourse and practice between the CE and recycling. Private and public institutions have rebranded a process that has been around for decades, with questionable success, into the cornerstone of a transition towards a circular economy. Recycling is one of the many strategies of the CE, but it is far from being a comprehensive one. By creating a fictional future within a speculative design workshop, we aim to provoke thinking beyond the dominating discourse in order to foster innovative ideas, observe attitudes and behaviours; and conceptualize a systems map of the plastics economy in Queensland through interactions observed.

Anya Phelan – (2) Griffith University
Circular ecosystem innovation and inclusive economic innovation in Western Cape York

Due to extreme distances and the resulting financial burden of access, the isolation of the Central and Northern Australian Outback mounts distinct challenges for people living and working in this remarkable and vast part of the world. Environmentally sustainable waste management and recycling is one of those challenges. This project focuses on community-based enterprise development and aims to support the advancement of people living in Far North Queensland through innovative recycling solutions and new employment opportunities. We examine how community-based enterprise and Indigenous entrepreneurship support dynamic and alternative economic models to address complex challenges in remote and outback Australia, particularly through the circular economy perspective. This project is part of a collaboration with the Weipa Town Authority, Napranum Aboriginal Shire Council, The University of Queensland, with funding from the Connellan Airways Trust.

Aziz Ahmed – (3) University of Wollongong
A community driven 3D printing micro-factory aims to democratize plastic recycling

The proposed concept aims to empower communities to recycle plastic waste and transform it into value-added products using 3D printing technology. The approach encompasses several key elements. Firstly, a reward point system will incentivize community members to recycle and sort plastic waste. Secondly, an online co-design platform will allow individuals with limited 3D drawing experience to select and customize a variety of household items for 3D printing. Thirdly, a net-zero 3D printing micro-factory will be established at the community level, equipped with all necessary tools and comfortable workspaces for recycled-plastic-based 3D printing. Fourthly, selected members of the community will receive training to operate the equipment. The system will be designed for low maintenance and operating costs, ensuring its sustainability in the long run. Community members can redeem their reward points to obtain 3D printed versions of their customized designs. The initial investment for the micro-factory could be jointly funded by government agencies and plastic product manufacturers, with the aim of promoting sustainable practices and reducing plastic waste in the community.

Matthew Flynn – (4) University of Southern Queensland
Processing end-of-life coated paper products for use as structural materials

Many products made from paper and cardboard are waterproofed with a plastic or wax coating, rendering them unable to be recycled with the rest of the waste stream. An example of this is single-use coffee cups, with an estimated 1 billion cups used in Australia each year, and less than 1% being recycled. This highlights the need for a circular solution for single-use cups. We are investigating the use of operationally simple, low-cost methods to convert waste such as coffee cups into value-added structural materials, diverting these materials from landfill. The use of simple equipment that can be implemented at small scale is particularly important in regional and rural areas, where an economy of scale cannot be achieved. The materials have been prepared various size-reduction techniques, and compacted into panels in a heat press. The impact of size-reduction technique on the structural properties of the panels will be presented.

Materials and processes

Chye Yi Leow – (11) The University of Adelaide
Hydrothermal Liquefaction of Plastic-Lignin Binary Mixtures

Hydrothermal liquefaction (HTL) is a unique process that exploits the properties of water near its critical point to break-down macromolecular bonds to form intermediate complexes and products. This presents a strong potential for HTL to be employed as an generic recycling technology for contaminated plastic wastes. In this study batch HTL investigations were undertaken at a scale, utilising plastic-lignin mixtures in a water medium at a reaction temperature of 350°C. The plastics evaluated were polyethylene, polystyrene, and polyethylene terephthalate. The HTL products were separated then analysed and quantified using GC-MS and thermogravimetric analysis. Preliminary findings indicate significant variations in susceptibility to decomposition via HTL for the range of plastics, with the catalytic effect of lignin affecting the extent of decomposition. By employing GC-MS, the characterisation of the products was achieved providing insight of the HTL of plastic-lignin binary mixtures.

Laila Halim, Matthew Hill and Leonie van’t Hag – (12) Monash University and CSIRO Applied Porous Materials Team
Plastic waste and its potential role in the future of green energy

Plastic pollution represents one of the biggest man-made challenges of our time. Advanced ‘plastic-to-plastic’ recycling techniques are highly beneficial solutions; however, a downside is that these methods can only be performed a few times before properties become undesirable. What if we established an improved circular economy and recycled into products with significantly longer lifetimes? And what if this fit into the picture of green energy: another colossal challenge facing humanity? Namely, plastic waste can be depolymerised into oils that could be employed as liquid organic hydrogen carriers – compounds that can be reused to sustainably transport hydrogen. Depolymerisation products could also be utilised to create separators in next generation batteries, or to form key components in solar panels. The applied porous materials team is working towards the development of membranes to separate out useful plastic breakdown products which could then form these exciting opportunities within the green energy sector.

Chris Rinke – (13) The University of Queensland
Biorecycling – a promising waste innovation

Plastic recycling rates remain low in Australia, mainly due to a lack of know-how to convert plastic waste into valuable end products. Our research aims to change the status quo and to provide experimentally verified, well-characterised, and efficient plastic degrading enzymes. We use advanced microbial genomics, molecular biology, and metabolic engineering workflows to discover, characterise, and optimise microbial proteins for plastic depolymerisation. The resulting enzymes will be applied to break down plastics into their building blocks, followed by the production of new plastic products, equal in quality to fossil-fuel derived virgin plastics. Alternatively, this biorecycling approach can be combined with microbial biosynthesis of high-value chemicals, such as bioplastics, to shift towards natural polymers. Overall, enzyme based biorecycling will help to valorise plastic waste and to transform circular economy principles into practice.

Jojibabu Panta – (14) Western Sydney University
Investigating the Feasibility of Recycled Polyethylene Terephthalate Glycol-modified as a Viable Printing Material for 3D Printing

This research presents an investigation on the feasibility of recycled polyethylene terephthalate glycol-modified (rPETG) using 3D printing for applications. The study focuses on the effects of processing parameters on mechanical properties of rPETG printed parts using Fused particle fabrication (FPF) 3D printing technology. The mechanical properties of FPF printed parts are evaluated using tensile tests according to ASTM D638 standard. The effects of the main 3D printing parameters such as layer thickness, infill density and number of contours on the mechanical properties of printed parts are studied. The morphology of the printed layers and their interlayer bonding of printed parts is also evaluated using scanning electron microscopy (SEM). Fourier transformation infrared (FTIR) spectroscopy is used to analyse the chemical structure of the printed parts. The results indicate that rPETG is a feasible material for 3D printing and that the mechanical properties of printed parts can be improved by optimising the processing parameters. The FTIR analysis confirms the presence of characteristic peaks for PET in the printed parts, suggesting that rPETG is a viable material for 3D printing. The study demonstrates the potential of rPETG as a sustainable alternative to virgin materials and provides insights into the optimal processing conditions for achieving high-quality 3D printed rPETG parts.

Brett Pollard – (15) Australian National University
Fully Bio-Based & Compostable Coffee Thermosets
Spent coffee grounds are a massively underutilised waste product from both an industrial and commercial standpoint. We have employed spent coffee grounds at a practical scale for the preparation of a polymeric system with real-world applications. We report our development of a novel and entirely green thermoset using sustainably sourced chia seed oil (selected for its high iodine value) which underwent epoxidation before cross-linking through catalyst- and solvent-free esterification with kelp-derived alginic acid at mild reaction temperatures (90 – 120 °C). The developed material showed reprocessability owing to the molecular rearrangements produced by thermally activated, catalyst free transesterification reaction of β-hydroxyester groups. Further, the composite is completely composted under backyard conditions within 3-4 months, providing a sustainable end-of-life strategy. The resultant suite of materials have potential industrial applications, and, to demonstrate this, several functional prototypes have been developed.

Tracey Read – (16) The University of Queensland
Are all bioplastics biodegradable in the sea?

More than 10 Mt of non-degradable commodity plastic leaks into seas and waterways each year. To combat this, there is an increased demand for bioplastic to replace problematic products. But not all bioplastics are equal, and judiciousness in material choices in circular economy planning is required. To understand the complex behaviour of bioplastics in waterways, 3 commonly known bioplastics (polyhydroxyalkanoate (PHA), polylactic acid (PLA) and polybutylene adipate terephthalate (PBAT)) were placed in four representative aquatic environments in Moreton Bay, Brisbane, over an 18-month field trial. The effects of processing (cast/injection moulded/extruded), as well as additives, product thickness, and surface versus benthic exposure, are being assessed, through exhaustive testing (not just mass loss). Preliminary results show that PHA – a natural polyester produced by bacteria – biodegrades faster than PBAT – a fossil fuel-based bioplastic – and that PLA – derived from corn starch or sugar cane – is showing very limited mass loss.

Knowledge and data

Anh Dang Nguyet – (5) Vietnam National Plastic Action Partnership 

Turning commitments to reduce plastic waste pollution into actions

Realizing an initiative of the World Economic +A6:F6Forum (WEF), the Viet Nam National Plastic Action Partnership (NPAP) together with few other pioneering NPAPs is a national multi-stakeholder platform established under the strategic partnership between the WEF’s Global Plastic Action Partnership (GPAP)i and the Ministry of Natural Resources and Environment (MONRE) to tackle plastic pollution and promote plastic circularity in Viet Nam. Through the NPAP, international and national opportunities for collaboration are identified and leveraged to support the implementation of Viet Nam ambitious national targets on plastic reduction by 2030. During its two year operation, the NPAP has commissioned diagnostic exercises, provided a national roadmap considerations for Viet Nam to reach its national goals for dealing with plastic waste pollution, and developed an intersectional gender context assessment of the plastic value chain report. The NPAP’s efforts foster the translation of global commitments into specific actions at the national level and contribute to the achievement of the UN Sustainable Development Goals.

Tom McColl – (6) Strategic Development Group
Bridging the gap – Methods to demonstrate impact and value to funders
We all value and understand the need for data-informed decision making by government and industry, though it sometimes feels like we’re speaking different languages. There’s often a gap between research objectives and funder expectations for achieving demonstratable impact or ‘results’, with implementing partners straining to demonstrate the pathways to impact and satisfy funder expectations. Through our work with governments and industry leaders across Australia, including CSIRO, Strategic Development Group has developed a deep understanding of how to bridge the gap in expectations between funders and implementing partners. This session will focus on models and methods to plan, demonstrate and communicate pathways to impact to a variety of stakeholders and importantly, funders. The session will outline the benefits of Impact Pathway planning, Theory of Change and using data-based storytelling to demonstrate impact and build understanding and shared value with funders.

Oliver Palin – (7) CLS Oceania
Tracking macro-plastic accumulation areas with Argos drifters and operational drift modelling
The Indonesian archipelago is rated globally the second contributor to marine plastic litter pollution. This has driven the government to increase its efforts to combat plastic pollution, on land, in rivers and in the ocean. Lack of systematic collection means that it often ends up in rivers and ultimately into the seas. With funding from the World Bank, the government of Indonesia set up an initiative to track the movement of plastic through a hybrid observation & model approach to determine the location of accumulation areas. The project deployed and tracked 24 Argos drifters over a year and set up a series of drift model simulations. Three river mouths were studied, located downstream from populated areas. Results showed that the movement of plastic litter is highly seasonal in the area and that in some cases, the plastic litter can escape the coastal environment into the deep ocean. Major onshore accumulation areas were identified. These represent priority areas where the marine litter should be collected.

Jack Fitzgerald – (8) Think Fencing
Enhancing uPVC recycling

Clement Chan – (9) The University of Queensland
The role of biodegradable plastics in tackling plastic waste – Challenges and potential solutions

Governments worldwide, including Australia, are implementing strategies to tackle the alarming accumulation of persistent plastic waste in the environment. To aid this transition, new ‘biodegradable’ materials are being rapidly introduced into the market. However, determining the role that the concept of ‘biodegradability’ could or should play from practical, policy, and regulatory perspectives is complex and lacks a clear solution. A holistic analysis of the state of play in terms of scientific knowledge, policy, and expectations identified confusion in terminology, a lack of clear policy and legislative regulation, the need for more consistent labelling, and limitations on waste management options as the key gaps and challenges. To address these challenges, a multi-faceted approach is required, involving the collection of scientific research to improve the understanding of biodegradation processes across environments, as well as the impact of plastic additives, information awareness campaigns, trustworthy quality assurance measures such as standards and labelling systems, and compliance enforcement through regulations.

Cao Ngoc Tu Xaychak – (10) CSIRO
Breaking Down Plastic Waste: Assessing the Environmental Impact of Chemical Recycling Processes

Chemical recycling is overlooked as a way to alleviate our plastic waste issue due to the perceived high energy demand. However, given that many plastic types cannot be mechanically recycled, chemical recycling presents an opportunity to bridge this gap. Thus, this project is dedicated to developing a centralised life cycle inventory (LCI) database for common chemical recycling technologies and use this database to establish life cycle impacts of these processes. Life cycle assessment (LCA) results indicated that plastic depolymerisation is the most environmental-friendly chemical recycling process due to the low energy usage and its ability to produce virgin-grade plastics. Plastic pyrolysis is also a favourable option as the petrochemicals produced from this technology more than compensated for its enormous heat requirement. Conversely, gasification of plastic waste did not produce sufficient syngas to justify its extremely high electricity demands. Results from this work can be used by policymakers and technology developers to promote the adoption of chemical recycling.

Knowedge and data – Microplastics

Sijing Li – (17) CSIRO
Risk characterisation of microplastics in recycled organic wastes – getting the right count
Although the majority of microplastics released into the environment are discharged into terrestrial ecosystems, significantly less attention has been focussed on the characterisation of risk in these systems. Risk characterisation requires accurate and reliable quantitative measurement of microplastics in complex environmental samples. Understanding risks in terrestrial systems is particularly urgent as Circular Economy principles are increasingly embraced and unintentional leakage of microplastics into the environment will occur to a greater extent. Based on our previous work in quantifying microplastics in wastewater and associated sludges, we are working to establish microplastic loads in three organic wastes commonly used for soil amendment; wastewater sludge, composts and organics from construction waste. This project involves collaboration with other laboratories using spectroscopic and mass spectrometry techniques to (1) verify baseline quantities of microplastics; (2) establish the most effective methodology for large scale monitoring programs; and (3) contribute to microplastic risk characterisation in land-applied organic wastes.

Biplob Pramanik – (18) RMIT University
Role of water shear force for microplastics fragmentation into nanoplastics in the wastewater treatment plants
Wastewater treatment plants (WWTPs) contribute to secondary microplastics (MPs) and nanoplastics (NPs) production due to mechanical stress from the mixing process. We investigated the fragmentation of pristine and weathered polystyrene (PS) particles (250 and 106 μm) using a four-blade mechanical impeller. Results revealed that pristine PS particles broke down into mean sizes of 120.6 and 95.6 nm, respectively, at 100 KJ/L energy density. The fragmented PS particles exhibited cracks, pores, damages, and rough structures, confirming the impact of mechanical stress. Crack propagation on particle surfaces, caused by water shear force, was identified as the primary MP fragmentation mechanism into NP. NP levels increased significantly after 40 minutes of mixing, with a 28-fold increase at 32 KJ/L energy density. These findings indicate that MP breakdown into NP is a continuous process during wastewater treatment, presenting a considerable risk to water environments due to NP release by WWTP effluents.

Chengrong Chen – (19) Griffith University
Detecting microplastics in organic-rich materials and their potential risks to earthworms in agroecosystems
We determined microplastics’ concentration, size-distribution, and chemical composition in 3 biosolids and 6 biosolid-amended soils. We also assessed short-term risks of MPs to earthworms’ (Amynthas Gracilis and Eisenia Fetida) survival rate and fitness (28 days exposure study). Biosolid-amended soils showed ≈30 times lower MPs content than biosolids, with microplastic fragment to fibre ratios between 0.2 – 0.6 and 0.3 – 0.4 in soils and biosolids, respectively. 77% and 80% of plastic fragments had diameter lower than 500 µm, while 50% and 67% of plastic fibres had length of less than 1000 µm in soil and biosolid samples, respectively. Polyethylene was major source of microplastic contamination in biosolid-amended soils, while polyethylene terephthalate showed highest concentration in biosolid samples. Spiked polyethylene MPs did not show any significant effect on earthworms’ survival rate. However, biosolid application significantly decreased survival rate of E. Fetida (81%) but showed no significant effect in A. Gracilis (93%).

Juniper Riordan – (20) Australian Microplastic Assessment Project (AUSMAP)
Bringing the Micro Into View Through a Microlitter Reduction Framework

A lack of a strategy to reduce microlitter (1-5mm) has contributed to ill-informed management of a growing pollution problem. In response, AUSMAP has created a Microlitter Reduction Framework based on hotspot identification, source tracking and stakeholder action. The framework was piloted in Dee Why Lagoon, NSW, which had been shown to be a microplastic hotspot. AUSMAP traced microlitter up-catchment from the lagoon through end-of-pipe sampling and demonstrated that microlitter varied in volume and type between land use types. Further, pit traps were installed across these areas with results showing that they prevented 450 kg of debris from entering the Lagoon over an 8 month period. Extrapolation of this data across the Dee Why catchment indicated that over a 12 month period, 3.1 million microplastics would enter the Lagoon. An education campaign with key stakeholders and controls on targeted sources followed. The process behind a successful MRF will be discussed.