This page is about the best small and large-scale community polystyrene & styrofoam recycling, repurposing, and reuse strategies. For those who don’t already know, polystyrene is a polymer made from the monomer styrene, a liquid hydrocarbon that is commercially manufactured from petroleum. Polystyrene is lightweight, fairly rigid, and an effective insulator. These properties make it very versatile and useful in a huge variety of products. Some common uses of polystyrene include packaging material for food and nonfood appliances, housings/casings in the electronic and communication sector, building insulation and liners in the refrigeration industry, and disposable medical ware1. For many of these uses, this hard plastic is treated with heat and pressure to form a foam product. Two of the main types of polystyrene foam are Expanded Polystyrene (EPS) and Extruded Polystyrene (XPS). Many people refer to these foam products as Styrofoam, however, Styrofoam is actually the trademark name for Dow Chemical Company’s popular XPS products. Thus, it is important to note that Styrofoam is technically a brand name for one company’s XPS products, and that XPS and EPS are types of polystyrene foam products2.
Typically, polystyrene is thrown in waste bins rather than being recycled. There are, however, processes that exist that allow it to be recycled. We discuss these here with the following sections:
A simple definition for polystyrene/Styrofoam recycling is the reprocessing of used polystyrene/Styrofoam to form new polystyrene/Styrofoam. To identify this material you can look for a 6 inside an arrowed triangle like the one below.
In this article, we share our research about the best way to recycle this material. While polystyrene can be recycled, it is a long process and we cannot currently recycle all of our polystyrene residues. Therefore, the most important thing we can do is to minimize our use and consumption of products containing polystyrene.
One Community is working to create global sustainability, and we recognize the importance of a consumer-driven effort to recycle more. We are researching the best small and large-scale recycling, repurposing, and reuse options for polystyrene/Styrofoam so we can implement these as part of the first of our sustainable village rollouts consisting of the Earthbag Village and Duplicable City Center. As we build the 7 sustainable villages, we will add our experiences and anything else we learn to this page. We are open sourcing our research and process in order to help both those building teacher/demonstration hubs to use our plans and those who would like to better understand how polystyrene/Styrofoam recycling works and how they can positively contribute to the process.
SUGGESTIONS ● CONSULTING ● MEMBERSHIP ● OTHER OPTIONS
Aidan Geissler: Sustainability Researcher
Angela Mao: Sustainability Researcher
Yomi Sanyaolu: Mechanical Engineering Graduate and Technical Writer
Due to its extensive use and disposal, pieces of polystyrene are quickly filling landfills, leaching toxic chemicals into our oceans, and are winding up in human bodies where they pose many potential health threats3. Eliminating or drastically reducing use is the best approach, and if we find ourselves with polystyrene/Styrofoam despite our efforts, recycling it makes a huge difference. We discuss both small and large-scale polystyrene/Styrofoam recycling here in the following sections:
Polystyrene is 100% recyclable and in 2016 around 120 million pounds of Expanded Polystyrene (EPS) was recycled globally4. This was made possible by the commercial recycling processes discussed below. More polystyrene would be recycled, but many consider it cheaper to produce new polystyrene than to recycle it. These costs account for production costs but not long-term environmental and health costs.
There are 2 different methods for recycling polystyrene (PS): “Granulation” for lighter polystyrene and “Compacting.”5. Compacting is the more commonly used process.
Granulation is the process of guiding recycled polystyrene through a granulator that grinds the material into beads which can then rejoin fresh polystyrene during the production process without affecting the quality. The more common compaction method involves compacting the material into dense bales, then converting them into pellets that can be used as raw material for creating new polystyrene products.
This diagram illustrates the compaction polystyrene recycling process:
Here is a video that describes the polystyrene recycling process in much more detail:
Here are three of the best strategies to ensure that polystyrene is properly recycled: drop it off at appropriate recycling sites, mail it into designated mail-back locations, and reuse it for loose-fill. Here are additional details and resources for each of these options:
If you want to help make recycling polystyrene easier and more economical for the recyclers, wikiHow describes in detail the most helpful actions you can take. They are summarized below:
Even though polystyrene is 100% recyclable, it isn’t always collected for recycling by local services due to the expensive cost of the process. In these situations, it is advised to either recycle or reuse7 Styrofoam yourself. Benefits of recycling polystyrene yourself include:
Next, we cover the different methods of recycling your own polystyrene both with and without the use of machinery.
There are 3 main machinery options for recycling polystyrene. All 3 solutions are focused on reducing the volume of polystyrene/Styrofoam because it makes later processing much more convenient8. The three machinery options are:
The solution with the best business potential is thermal densification; these are the advantages of the machine:
Unfortunately, there are drawbacks to this technology; these limitations are:
All 3 types of machines can be found on the Alibaba website and are compared below, along with the non-machinery DIY solution described in the next section.
The following is one possible method to recycle the Styrofoam yourself in your home with no special equipment needed:
A non-machinery method to recycle waste Styrofoam is using it to form insulation blocks. Styrofoam insulation is very flammable though, so you want to only use it where safe and check with your county to make sure it is legal.
Equipment needed for this process is Great Stuff™ binding foam, disposable gloves, cardboard boxes, old paper, and tape. This tutorial is sourced from instructables.com and goes as follows:
Warning: Don’t use in places containing fire hazards, very flammable!
If you plan to use polystyrene/Styrofoam for insulation, it is important to assess its effectiveness. The R-value of a material is a measure of how well that material resists the flow of heat, and thus tells you how effective a material is at insulating. The higher the R-value, the greater the material’s insulation effects. We have researched the R-values for various commonly used insulation materials, for polystyrene products, and made predictions about the expected R-values of our recycled polystyrene products. Here are those results (per inch):
Note: recycled polystyrene is typically not recommended for insulation for two reasons: it is highly flammable and for this reason code probably does not allow its use for any type of living space. Also, in any loose-fill form, the insulation property of the material is drastically reduced. For example, packing peanuts are made from Expanded Polystyrene, so while the R-value of the material itself is about 4, all of the air in between the peanuts (R-value of about 1) makes this material a poor insulator in loose-fill form. If you compressed packing peanuts enough to eliminate all the gaps of air though, you would achieve an R-value similar to that of EPS board.
Some of the most commonly used insulation materials are Fiberglass, Rock Wool, and Cellulose. As seen in this graphic, except for rigid Fiberglass with an R-value of 4, all of these materials have an R-value of below 3.5. Meanwhile, the R-value of polystyrene Board ranges from 3.85 to 5.2. Therefore, polystyrene boards are a much better insulation material than many commonly used insulation materials.
Through our research did not yield specific R-values for the 4 different methods of recycling polystyrene into insulation materials, we made reasonable predictions. We expect loose-fill insulation such as the output from a Granule Machine to have an R-value similar to that of loose-fill polystyrene beads, which is 2.3. More promisingly, we expect any method of creating recycled polystyrene blocks to have an R-value similar to that of commercial polystyrene boards, which would fall somewhere between 3.85 and 5.2.
Due to the flammability of these polystyrene products, they are not recommended for insulation in housing structures. Therefore, One Community only plans to use polystyrene insulation in our Highest Good food structures and/or other non-housing structures.
After completing the research above, we compared the 4 different options for processing used Styrofoam. The factors we assessed were: End-product Uses, Cost, Labor, Safety, and Sustainability. Here is the resulting table:
This page is open source and its purpose is to educate people globally on how polystyrene waste is processed, their options on how to deal with it themselves, and potential business ideas for communities or organizations that receive/produce large amounts of polystyrene. Our plan to address polystyrene is first and foremost to minimize the purchase of polystyrene products as much as possible. Any polystyrene we accumulate despite these efforts will be reused as packaging material or repurposed as insulation for Highest Good food structures. We will only choose to use them for Highest Good food structures because these structures can be insulated legally and safely even with polystyrene’s highly flammable properties. If we ever happen to accumulate excess polystyrene that we cannot repurpose, we will follow best practices for recycling polystyrene.
One Community has invested extensive time and research into the best small and large-scale recycling, repurposing, and reuse options for polystyrene/Styrofoam (and plastic, glass, paper, clothing, metal, food, and other perishable and non-recyclable items). For polystyrene/Styrofoam that cannot be reduced or reused as packaging, a great option is repurposing it as insulation. We will open source share our group’s experience reducing, reusing, and recycling our polystyrene as part of the development of the Earthbag Village and Duplicable City Center. We will evolve this page with videos and other data from this process as we use what we learn to help us improve our recycling, repurposing, and reuse strategies as we build each of the next 6 sustainable village models and grow to a community of hundreds.
Q: What is the difference between Styrofoam and Polystyrene?
Polystyrene is a polymer made from the monomer Styrene, a liquid hydrocarbon that is commercially manufactured from petroleum. There are three main types of polystyrene products: regular plastic, foam, and film. The most widely used varieties of polystyrene foam are Expanded Polystyrene (EPS) and Extruded Polystyrene (XPS). Styrofoam is technically the trademark name of XPS products sold by Dow Chemical Company, but is colloquially used more generally to refer to any polystyrene foam products (just as we use Kleenex to refer to facial tissues).2
Q: What are the potential human health impacts of Polystyrene?
Styrene, the building block of all polystyrene products, has been deemed a possible carcinogen by the World Health Organization (WHO). The EPA also notes that Styrene can cause a host of effects such as headaches, fatigue, dizziness, confusion, and malaise. Additionally, Styrene can disrupt regular hormone cycles, cause menstrual irregularities, and high exposure can even damage liver and nerve tissue.3
Q: What are some of the environmental impacts of Polystyrene?
The manufacturing process of polystyrene foam releases hazardous chemicals, such as Chlorofluorocarbons (CFCs) and Hydrochlorofluorocarbons (HCFCs), that deplete the ozone layer, which acts as a shield protecting us from much of the harmful UV radiation from the sun. Polysytrene products also pose a great threat to oceanic ecosystems: these products contain toxic chemicals that are leached into the ocean and consumed by marine life.3
Q: Is this guide complete?
No, we won’t consider this guide a complete tutorial until we finish our own construction of this component, confirm all the details, and add to this page all the related videos, experiences, and other updates from that build. In the meantime, we’re always happy to have the help of any qualified and experienced individuals with input that may make it better. If you are especially interested in this topic and would like to collaborate with us please click the button below. Any further questions related to this article you can contact us here, we will answer them and add them to this section.
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