Status of Plastics Waste in Circular Economy in the USA

Abstract

Circular economy, an economic system where waste is utilized as an economic input, is currently the subject of much interest. Methods to incorporate all wastes into circular economy have not been developed. This paper discusses the current status and options for including plastics wastes in circular economy in the USA. Utilizing some plastics wastes as fuel is the most feasible path to doing so at present. Completely closed-loop circular economy for plastics would require fundamental changes in how plastics-based products are designed and manufactured.

1 Introduction

The term circular economy has become popular in recent years (Kok et al. 2013), but the concept is not new. The basic definition of circular economy is simply an economic system based on what is traditionally defined as waste being redefined as an economic input, as opposed to a linear economy (Fig. 1) in which materials are extracted, used, and disposed of (Hoomweg and Kennedy 2013). Some definitions of circular economy also include reduction of nonrecoverable pollutants and increased durability of products (lengthening of the circle) (Lahti et al. 2018). Circular economy can therefore in practice be considered essentially synonymous with the term zero waste economy.

Fig. 1

Linear economy resource management approach

Waste is something that is considered to be of negative value and therefore is designated for removal, by its owner (Michelini et al. 2017). Historically, waste management has been performed for the purposes of sanitation, health, and esthetics (Michelini et al. 2017). As such, waste was managed by disposal, except in cases where the waste was economically and functionally competitive with virgin materials. More recently, secondary (waste) materials use (more popularly referred to as recycling—a term that, like circular economy, indicates the cyclic nature of the process) has been encouraged or mandated for perceived environmental benefits, rather than only free-market reasons. Circular economy is an expansion of encouraged or mandated recycling—it is an economy requiring a cyclical materials system. To achieve such implies not just materials recovery, but also that the cyclical use of materials be incorporated in all aspects of the economy—including product design, manufacture, and use.

Plastics materials are an increasingly large quantity and percentage in the US waste stream. From Table 1, it is noted that total plastics in the USA MSW increased from 390,000 US tons in 1960 to 34,500,000 in 2015—an increase of almost 90 times (2015 data are the most recent published by the US EPA). From Table 2, it is seen that at the same time, period plastics increased from 0.4% to 13.1% of the USA MSW. No other single waste material has had nearly that rate of growth.

Table 1 Materials generated^a in the municipal waste stream, 1960–2015 (thousands of tons) (5)

Table 2 Materials Generated^a in the Municipal Waste Stream, 1960 to 2015 (percent of total generation) (5)

A significant reason for this quantity and percentage increase is substitution of plastics (a newer material) for older materials (glass, metals, and paper) in existing products. Tables 1 and 2 indicate a slowing of plastics wastes’ quantity and percentage increases (as plastics become mature materials) but the increase still continues.

Given the large, and still increasing, portion of plastics in the USA MSW, it is critical for the USA economy to incorporate plastics wastes into production of new products if a circular economy is to be achieved.

2 Governmental Involvement in MSW

Nationwide US waste management laws began in 1965 with the “Solid Waste Disposal Act” (Fig. 2). This was followed by the Resource Conservation and Recovery Act (RCRA) of 1976. The RCRA program, implemented by the US EPA and its partner states, tribes, and local governments, protects communities and the environment from the improper management of solid and hazardous waste, cleans land and water, conserves resources, and empowers citizens by delivering information and opportunities that enable communities to participate in decision-making processes.

Fig. 2

Adapted from RCRA’s Critical Mission and the Path Forward, 2014 (USEPA 2014)

The evolution of significant RCRA legislation

RCRA also serves as a legislative basis for EPA’s Sustainable Materials Management (SMM) program, which is a systemic approach for promoting using and reusing materials over their life cycle. The program has four primary goals: to decrease the disposal rate; reduce environmental impacts; increase socioeconomic benefits; and increase the capacity of communities to adopt SMM practices. The SMM program set three strategic priorities as follows:

• The built environment

• Sustainable food management

• Sustainable packaging.

3 Plastics Recycling

Table 3 shows the US recycling rates for MSW component materials, 1960–2015. It is notable that plastics wastes have the lowest recycling rates of all MSW categories except food (which, as a wet waste, has only recently been subject to significant organized source separation in the USA).

Table 3 Materials recycled and composted^a in municipal solid waste, 1960–2015 (percent of generation of each material)

There are multiple reasons to explain the low plastics recycling rate, including:

• Collection/transport/separation

  • some plastics (i.e., EPS) are of very low density, making transport per weight expensive and energy inefficient.

  • plastics are often strongly attached to other plastics or nonplastic materials (i.e., multi-polymer packaging, appliances) making separation into pure polymers expensive if not feasibly impossible.

  • some plastics waste (i.e., agricultural) are produced in remote areas.

  • contamination (most likely the result of single-stream recycling practices).

• Technological

  • Thermoset plastics cannot be remelted and reformed, significantly limiting their input into new products.

  • Depolymerization is not yet commercialized.

4 Legislative and Industrial Initiatives

Most USA governmental actions aimed at managing plastics wastes have occurred at the local level. Some municipal governments have banned or restricted the use of specific plastics products that are perceived as being particularly problematic (single-use bags, straws). Such actions may reduce plastics wastes but do not provide for reintroduction of wastes into circular economy.

Some states have taken actions. California, for example, has passed a regulation requiring that some disposable food service items be reusable, recyclable, or compostable by 2021 (Rajbanshi 2019; California Legislative Information 2018). However the regulation is limited to certain items at certain state facilities, so its scope is not broad. Also, rather than causing plastics items to be reintroduced into circular economy, the result could instead be substitution for non-plastics items.

At the federal level, legislation has been proposed to introduce extended producer responsibility to manufacturers of plastics packaging (Product Stewardship Institute 2019). However the proposal also calls for bans or disincentives for some plastic products and container deposits. Also it is unclear if this will become law and, if so, in what form.

Overall, there is not significant law to encourage plastics in circular economy.

The plastics industry has been willing for decades to find uses for some plastics collected in recycling programs. However the overall USA plastics recycling rate, as of 2015, is 9.1% (USEPA 2019) (although some specific products have much higher rates). This indicates that industry has not yet found much circular economy pathway for plastics.

5 Options for Plastics in Circular Economy

There is currently not any indication that the mentioned obstacles will be overcome in the near future. Therefore, it appears that, if the USA is to move toward a circular economy (Fig. 3), fundamental changes in plastics wastes are needed. This would include replacing some current polymers in products, redesign of many products, and elimination of some products. This runs contrary to usual free-market economics and would have many secondary consequences. It is not feasible.

Fig. 3

Closing the loop for circular economy

For plastics in the USA, utilizing some plastics wastes as fuel appears to be the most feasible current method for plastics to be a part of movement toward circular economy.

The USA can transform current stalled inefficient plastics recycling operations and create innovative solutions. Creating an effective infrastructure is a key to achieve transformation and the solutions can be listed as follows (Bara and Leonard 2018):

• Producing plastics from nonfossil feedstocks

• Displacing fossil energy by renewable energy during the production and distribution of plastics

• Market transformation through technological innovation: Researching and developing new production processes to achieve longevity, reusability, and reduce the waste

• Considering plastic waste as a resource

• Developing new sustainable business models

• Market-based incentives

• Development of new institutional infrastructure

• Supportive regulations

• Collaboration between researchers, businesses, consumers, and decision makers

• A systems approach to identify the opportunities and creating an ecosystem that strategies and policies can impact each other efficiently.