When the trail gets steep

when I was younger I loved going on long, meandering trail runs on the outskirts of my hometown in the Australian countryside. It was my favorite way to escape the stresses of everyday life. I didn't worry about time or distance or pace. I just enjoyed the immersive and meditative experience of running in a beautiful place. So, when I was back in my hometown for a visit after a tough first year of my Ph.D. program, I thought a trail run was just what I needed. But instead of helping me relax, the run did just the opposite: It made me anxious. In the end, I figured out why

The role of biodegradable plastic in solving plastic solid waste accumulation

This chapter presents the idea that there are a range of target plastic products where substitution with biodegradable plastics would be the most effective way to address the issue of plastic solid waste accumulation. These can be determined by considering material flows and identifying the materials most likely to be mismanaged or not practically recyclable (e.g., agricultural films, single-use bags, multilayer materials, linings for cardboard, items likely to be used in events with a large organic waste fraction). However, this view is not shared by all, and the debate surrounding the role of biodegradable plastics in solving plastic solid waste accumulation and assisting the transition toward a circular economy remains unresolved. Thus, in this chapter, both sides of the debate are presented and reviewed, with the conclusion being that biodegradable plastics should be considered as part of the solution. However, their efficacy in providing an environmentally sound solution to solid waste accumulation will depend on the coemergence of affordable waste sorting technology and investments in organic waste handling facilities (compost and anaerobic digestion). Further discussion is raised around a number of important points: 1. That parts of the debate questioning the utility of biodegradable plastics need to be challenged as they revolve around factors which while having some basis are misinformed and/or can be addressed. 2. That although mechanical recycling normally emerges as the superior waste processing option by life cycle analysis, all plastic materials have a limited mechanical recycling lifetime (while some materials are simply nonrecyclable) and therefore materials need to also be chemically or biologically recyclable if a “recycling loop” is truly to be implemented. 3. That there will always be a certain level of leakage of materials to the environment, regardless of the improvement in our collection systems. Biodegradable plastics would help to alleviate the impact of this leakage

Public attitudes towards bioplastics – knowledge, perception and end-of-life management

The aim of this research was to understand current knowledge and perceptions regarding bioplastics. Results were gathered through an online survey of 2518 nationally representative Australians. The results indicate that the Australian public's knowledge of bioplastics is low, but perception, particularly of biodegradable plastics, is positive. Biodegradable plastics were perceived as better for the environment than ‘normal plastics’ and even ‘easily recyclable’ plastics. The majority of respondents (58%) said they were unsure whether biodegradable plastics can have negative environmental impacts. Sixty-eight percent of people say they would like to see more of the plastic items they use be biodegradable. If this becomes the case, there will be an increased stream of bioplastics entering the recycling system with 62% of people saying they would dispose of bioplastic items in the recycling bin. In light of the results presented in this work, potential issues relating to the introduction of bioplastics are raised and the role that governments and local councils can play in driving the development of the standards, labelling and waste management options that will need to be introduced alongside the introduction of wider bioplastic materials use are discussed

Polyhydroxyalkanoate coatings restrict moisture uptake and associated loss of barrier properties of thermoplastic starch films

This work investigates the use of polyhydroxyalkanoate (PHA) films as moisture barriers for thermoplastic starch (TPS) films, to produce biodegradable, multi-layer materials with high gas barrier properties. This is a necessary extension to the limited work available on this topic and confirms that PHAs are suitable coating materials for TPS films intended for use in food packaging. Under storage conditions of up to 75% relative humidity (RH) for 2\ua0weeks, a PHA coating maintained the moisture content (MC) of the TPS below the point at which its barrier properties were detrimentally affected. Furthermore, for PHBV coating thicknesses of 91–115 μm, the MC of the TPS remains significantly lower than uncoated TPS for the duration of the experiment (>25 days). The flux of water into the coated TPS fit to a model based on Fick's law. However, when the multi-layered films were stored at 95% RH delamination occurred within 24 h. Preliminary investigation into possible material design improvements showed that the addition of a small amount of PHA to the TPS layer prolonged the time to delamination

Public attitudes towards plastics

Understanding and engaging the public is key for ensuring the success of government and industry initiatives aimed at addressing the problem of plastic waste. However, there has been little focus on documenting the general public's attitudes towards plastics. This study examines public beliefs and attitudes towards plastics in Australia and provides insight on a global level. The research was conducted using an online survey of a nationally representative sample (2518 respondents). Overall, the survey results indicate that the public view plastics as a serious environmental issue. Plastic in the ocean had the highest mean rating for seriousness out of nine environmental issues, followed by two other issues relating to plastic waste production and disposal. Whilst there was an association of plastics with food packaging and convenience, there was more of a negative association with the use of plastic overall. Eighty percent of respondents indicated a desire to reduce plastic use and the majority of respondents believe that paper and glass are more environmentally friendly packaging materials than plastics. However, the results showed that many respondents do not translate their aspiration to reduce plastic use into action. Overall, while a majority of the Australian public are concerned about plastics as an environmental issue, they place the bulk of the responsibility for reducing the use of disposable plastic on industry and government

Environmental impact of biodegradable food packaging when considering food waste

From a waste management perspective, high-barrier, multi-layer, biodegradable food packaging could be a useful replacement for current multi-layered packaging that is non-recyclable and non-degradable. Whilst there is still technical research required, it is envisioned that a biodegradable thermoplastic starch (TPS) and polyhydroxyalkanoate (PHA) layered material could be a promising target. However, there is currently limited research identifying what environmental trade-offs are associated with using such a material meaning there is no guidance regarding what design characteristics are important to consider during development of such packaging. The aim of this study was to quantify the greenhouse gas (GHG) trade-offs associated with using the proposed biodegradable packaging and identify the important design considerations. To our knowledge this is the first study to discuss the implications of including food wastage when assessing biodegradable food packaging materials. It also considers the impacts of landfill methane capture efficiency, which is an important aspect as biodegradable packaging may release methane when disposed of in a landfill whereas non-biodegradable packaging is inert. However, a key result is that when food waste is included in the system boundaries, it contributes over 50% of the GHG emissions associated with the system, regardless of whether the package is biodegradable or not. This shows that even for biodegradable packaging, reducing food waste is a key design consideration. In fact, the negative environmental impacts associated with disposal of a PHA-TPS packaging in landfill with low gas capture rates can actually be offset if the package reduces food wastage (beef) by approximately 6%. The overarching result is that a PHA-TPS food packaging only delivers positive GHG outcomes if it reduces food wastage or increases the viability of biological food waste processing. (C) 2018 Elsevier Ltd. All rights reserved