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Engineering, Environmental
Though solutions are needed across all sectors, a material considered to have one of the highest potentials and needs for improvement is plastic. Not only in recent years, the problems resulting from incorrect handling of plastic waste have been identified to be threatening the environment in a variety of ways [8]. Insufficient collection and waste treatment following the disposal lead to leakage directly into the environment, incineration, or landfilling of the ubiquitous material. The topic of plastic pollution and other end-of-life issues have also been picked up by the public since many products made from this material are used by private households. An example in this context is plastic packaging. With packaging having the largest share amongst plastic production and it being a fast-rotating consumer good, a societal focus has been set on plastic packaging as an environmental threat. Despite the immense benefits of plastic packaging to society, the accumulation and treatment of end-of-life plastics are creating a global environmental challenge. To reduce plastic debris in the environment, for example, in the oceans, it has become clear that a focus on design for life and end-of-life is a priority. This concept, also called Design for Life Cycle (DfLC), has been identified to play a major role in minimizing environmental impacts of all kinds of consumer products.
- Design for Life Cycle
- circular economy
- waste management
- circular design
- plastic packaging
- producer responsibility
- recyclability
- climate change
- life cycle assessment
1. Introduction
The lacking potential of product circularity across all sectors in our economy has been identified as a major environmental concern during the last decades [1]. With consumers asking for more sustainable products and the industry trying to provide environmentally sound yet economic solutions, there is a strong demand for standardized processes and goals [2]. While the EU Circular Economy Action Plan as a part of the European Green Deal aims at defining targets and minimum requirements for the future, the industry is left with the task to meet the requirements [3]. To make these goals achievable and attractive, easy-to-implement approaches are needed. Despite their ease of implementation, such approaches must be backed by scientifically obtained knowledge. Consequently, Life Cycle Assessments (LCAs) are commonly used as a well-suited tool to achieve circular economy goals [4,5].
Though solutions are needed across all sectors, a material considered to have one of the highest potentials and needs for improvement is plastic [6,7]. Not only in recent years, the problems resulting from incorrect handling of plastic waste have been identified to be threatening the environment in a variety of ways [8]. Insufficient collection and waste treatment following the disposal lead to leakage directly into the environment, incineration, or landfilling of the ubiquitous material [9,10]. The topic of plastic pollution and other end-of-life issues have also been picked up by the public since many products made from this material are used by private households [11,12]. An example in this context is plastic packaging [7]. With packaging having the largest share amongst plastic production and it being a fast-rotating consumer good, a societal focus has been set on plastic packaging as an environmental threat [6,11,13]. Despite the immense benefits of plastic packaging to society, the accumulation and treatment of end-of-life plastics are creating a global environmental challenge. To reduce plastic debris in the environment, for example, in the oceans, it has become clear that a focus on design for life and end-of-life is a priority [14]. This concept, also called Design for Life Cycle (DfLC), has been identified to play a major role in minimizing environmental impacts of all kinds of consumer products [15,16].
From the points above, alongside the European Commission’s ambitious goal of only introducing recyclable or reusable plastic packing by 2030 as part of a way to a more circular and therefore more sustainable economy, it can be derived that measures are needed to improve the circularity of products [6]. Many properties affect the recyclability of packaging. Among them, the design largely contributes to the performance of the material valorization in further cycles [17]. Therefore, it is one of the main objectives of the DfLC approach to achieve a product design that has the use of the entire product or the materials within a circular economy in mind [18,19].
Thus far, the utilization of plastic materials has mostly been linear [6,20,21]. Given the decreasing reserves of fossil fuels and finite capacity for landfill sites, this linear use of hydrocarbons through packaging and other short-lived applications of plastic is not sustainable [14]. The comfort of disposing of a product rather than reusing or recycling it in addition to the low price and the seemingly unlimited availability promoted a throw-away society [20,22]. Facing the regulatory requirement of developing towards a more circular economy [20], there are several potential solutions to strengthen the weak link between the end-of-life stage of packaging and reuse. With solutions ranging from the substitution of fossil to bio-based resources or the biodegradability of products to immediate reuse by the consumer, approaches for circular products differ widely [14,22]. These approaches are illustrated in Figure 1. Regardless of the chosen approach, the circularity is largely determined during the design stage of the product [23].
Figure 1. Circularity approaches between disposal and recovery.
To simplify the process of optimizing the circular design of packaging solutions, this paper aims at providing product designers of non-food plastic packaging with easy-to-implement measures. Even though guidelines for environmentally sustainable packaging design based on LCA exist, outlining the specific impacts of certain product characteristics is not common. Product designers are left with requirements or recommendations without knowing the indirect environmental consequences their decisions have. Hence, it is one goal of the study to qualitatively and quantitively evaluate the environmental burdens of a broad spectrum of product designs and characteristics. This is important to build awareness for the impact of design features on environmental performance. Some of the assessed attributes are already known to influence the environmental burdens because of reduced recyclability and therefore circularity. Thus, the motivation for the study is not to create an entirely new guideline but to stress the importance of single measures by providing background knowledge. Herein, only practically relevant technologies are part of the assessment, while scientific fringes are excluded. The specific results are displayed and ranked for all design options considered.
2. Design for Life Cycle
In order to comprehend the environmental impacts caused by the product’s design during the stage of development, the field of DfLC delivers methods, tools, and principles for designers, providing lessons learned from already-implemented LCA studies before a specific design is given [16,19]. LCA is defined as the compilation and evaluation of the inputs, outputs, and potential environmental impacts of a product system throughout its life cycle [25]. DfLC guidelines, therefore, play hand-in-hand with LCA, with a focus on evaluating the entire life cycle at the design stage. For the approach various names and definitions have been established, all having closed-loop design as a main or subgoal. Some of the more common names for concepts similar to DfLC are design for environment, design for X, design for sustainability, and cradle-to-cradle [18,23,26,27]. As a closed-loop design is one of the main targets of this article, the term DfLC is used, having in mind that other concepts overlap and are part of life cycle approaches as well. DfLC assesses the environmental impacts associated with a product, process, or service throughout its life or duration with hindsight to the design phase. Hence, the DfLC approach saves designers time by pointing out improvement potentials without the need to conduct LCA studies for every possible design option [16]. Nevertheless, the required generalization comes at the price of increased uncertainty, limiting the feasibility of specific DfLC guidelines [16].
According to the waste hierarchy established in the EU Directive 2008/98/EC, the avoidance and reduction of used material have the highest priority, followed by the reutilization of the product and material recycling (Figure 2) [28]. However, as the reduction of material is only possible up to a certain degree, and reutilization is not possible for all product categories due to hygiene and commodity requirements, recycling has been identified as the often more feasible option in practice [29]. Therefore, the herein discussed DfLC measures for plastic packaging have a focus on improving recyclability. The overview presented in this paper provides a basis for future development of design-integrated recycling assessments of non-food packaging using life cycle thinking within the guidelines of DfLC. The results of this study can be used to support decision making and highlight the importance of recyclability and input of recycling material, which are required according to the newest EU Guidelines for packaging [6].
Figure 2. Waste hierarchy, derived from EU Directive 2008/98/EC [28].
3. State of the Art Plastics Recycling
The recycled fractions of plastic waste from private households and the used processes and machines vary not only from country to country but are also specific for each recycling plant [30]. Here, the available recycling infrastructure plays a major role in successful recycling. However, some key processes remain largely unchanged and are a part of most facilities. In the following, only a few of these steps in the recycling process, in which the results are directly influenced by common plastic packaging designs, are briefly described and shown in Figure 3.
Figure 3. Typical steps of plastic waste recycling in Germany.
One of the central steps in the sorting of plastic packaging waste is the automated sorting by a near-infrared scanner (NIR-Scanner) [31]. Herein, the processed packaging is irradiated with infrared light, and the packaging is separated accordingly by compressed air nozzles [32]. Hindering attributes can be opaque packaging due to low reflection rates, fillers, and compounds as well as labels or sleeves covering the main (target) material [33].
During the washing of plastic packaging, product residues, labels, and other impurities are separated from the targeted material fraction [34]. Most commonly, water-based washing solutions in combination with detergents are used [35]. Some product attributes (e.g., insoluble adhesives or extensive contamination) can hinder the success of the process [33].
Another processing step of importance is the density separation of plastics. Although there are other technologies available, this process is mostly carried out by swim–sink separation [35]. Depending on the material to be recycled, either the swimming fraction (e.g., for PP or PE) or the sinking fraction (e.g., for PET) is processed further [33]. Design flaws, including labels not soluble in the preceding washing process or additives changing the polymer’s density, pose a problem for targeted sorting [33,36].
This entry is adapted from the peer-reviewed paper 10.3390/su14074076
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