The lifetime of plastic
19 July 2018
The plastic waste challenge is complex. There are thousands of plastic polymers, numerous additives and almost limitless applications and formats. And the list of potential solutions is almost endless, running from outright bans – through scaling up recycling or replacing everything with bioplastics – to harvesting the troublesome material from the oceans. Confused? Me too.
So, I was really pleased when my colleagues completed their detailed study of plastics issues and proposed a ‘use-phase’ based approach for considering plastic waste and the potential solutions. It brings clarity to a complex problem.
Drawing upon life-cycle thinking and the growing literature on plastics, the framework considers plastic items in terms of their ‘use phase’ – in other words, the length of time for which a given plastic item is used for its intended purpose. This is valuable because it recognises that the lifetime of an item correlates closely to two factors: firstly, the way that the product is typically discarded; and secondly, the potential actions you might take to reduce the negative impacts across the whole lifecycle.
The framework puts plastic items into five categories, as illustrated in the infographic below.
Let’s consider each in turn:
Category one comprises small format items with a very short use phase: items that typically are used for less than a day, sometimes just hours, minutes or even seconds. Think cotton buds, coffee stirrers, straws and sanitary towels. These are the bad boys of the plastics waste world. Their impacts as waste are significant, particularly in the context of their very limited life.
Because of the setting in which they are used, they are not particularly conducive to separate collection for recycling and, in the case of sanitary items and cotton buds, have a tendency to be flushed away, often becoming marine plastic debris.
The main interventions for tackling these items are to: eliminate them where possible – do we really need disposal coffee stirrers?; replace them with reusable alternatives – what happened to the trusty metal tea spoon?; and consider the potential to replace them with biodegradable materials – that is, materials that will degrade in the natural environment.
Category two is also for items with a very short use phase, but which are larger, such as disposable cutlery, cups and plates (‘serveware’), takeaway packaging and carrier bags. These items could potentially be recycled but, again, tend to be used in contexts where there is a high risk that they do not make it back into the recycling stream and are often discarded as litter or put in the wrong bin in the street.
These products can be (and increasingly are being) replaced with reusable alternatives, such as reusable coffee cups. For some items, such as serveware, there may be potential to replace them with compostable alternatives but if we chose this route, we need to make sure that we have sufficient, commercially viable treatment outlets and that the collection systems work to keep them separate from other materials, avoiding potential cross contamination issues of compostable and dry recycling streams.
Category three is where the large bulk of plastic waste is generated. These are items with a short life of between one day and two years and include a broad range of products such as food and drink containers, agricultural films, cosmetics and healthcare products. Many of these items fulfil valuable functions and banning them would have significant negative impacts, such as increased food waste due to poorly protected food.
The focus of interventions here is on improving functionality during the use-phase and also, but to a lesser extent, on the end of life options. This requires: improved product design to extend product life; investment to significantly increase the scale of collection and sorting infrastructure; designing products so that they can recycled easily, for example avoiding complex combinations of materials and polymer rationalisation; and driving up demand for recycled plastics by using more recycled content in new products. The Plastics Pact sets out some good ambitions with respect to the latter two statements.
Categories four and five represent the products that are in use for a significant length of time so comprise goods that are not typically littered and become waste in very different ways. They therefore warrant quite different interventions.
Category four (2 to 12 years) includes car parts, electrical goods and toys.
Category five (over 12 years) comprises building products such as pipes, insulation boards, roof tiles and also furnishings that use plastics such as carpets.
Given the fundamental purpose of these products, the most appropriate actions focus on increasing durability and repairability, and on increasing recycling after use. This will require improved sorting and separation equipment, particularly for electronic waste and vehicle parts. For building materials, given the extended length of time for which they are ‘in use’, it will also be important to improve labelling and tracking of materials so that they can be identified and separated for recovery in the (potentially distant) future.
So, it’s not one-size-(or intervention)-fits-all. But once you start thinking of things in terms of how they are used and discarded then it becomes a bit simpler.
‘Eliminating avoidable plastic waste by 2042: a use-based approach to decision and policy making’ was written by Resource Futures and Nextek and published by the Resourcing the Future Partnership.
Image source: CIWM Online Journal