AskPablo: About Plastic Recycling

50px-U%2B2673_DejaVu_Sans.svg.pngThis week I got the following question from Barb:

My community as well as all other surrounding cities here in Ohio only accept plastic with a #1 or #2 to recycle. Why can’t the other numbers be recycled? Is there any effort among businesses to use the most oft recycled plastics (i.e. only use #1-4) or an effort in the “green” community to encourage the use of a select type of plastic so that eventually it’s economically feasible for recycling centers to recycle all plastic containers?


The sad truth is that the vast majority of plastics are not recycled, they are “down-cycled” at best. Rather than using returned soda bottles to make new soda bottles, “down-cycling” refers to their use in making lower-grade plastic products such as park benches, milk crates, and plastic speed bumps. The reason for this is that there are thousands of types of plastic and a huge selection of additives that contaminate the quality of the recycled plastic. Additionally, contaminants such as food residue and non-plastic materials further degrade the quality.
Among the most common and most recyclable plastics are PET (#1) and HDPE (#2), which is probably why Barb’s community accepts them. The remaining recycling numbers (Resin Identification Codes) are either less common, more difficult to recycle, or not really recyclable. Let’s have a look at the different types of plastic:

#1 – Polyethylene terephthalate (PET)

Made into soda bottles and polyester fibers.

#2 – High density polyethylene (HDPE)

Made into milk bottles, grocery bags, and bins.

#3 – Polyvinyl chloride (PVC)

Made into pipes, carpet backing, vinyl siding, and those annoying blister packs that everything comes packaged in these days. Target and others have announced that they are fazing out the use of PVC because of its toxicity in production, use, and disposal. Making PVC releases dioxins, furans, and other persistent organic pollutants. In house fires the toxic smoke from PVC and other plastics is more likely to kill than the fire itself.

#4 – Low density polyethylene (LDPE)

Made into dispensing containers like shampoo bottles and shopping bags.

#5 – Polypropylene (PP)

Made into fibers and molded plastic parts. Patagonia currently accepts their old Capelene undergarments for recycling into new garments but recycling of synthetic clothing is not yet widespread.

#6 – Polystyrene (PS)

Used in clear cups, insulating materials, and in expanded polystyrene, also known as Styrofoam. Due to the low weight to volume ratio it is more economical to make Styrofoam from virgin petroleum than to transport it to a recycling facility.
#7 – Other
Includes acrylic, PLA, polycarbonate, nylon, fiberglass, and others. This category is a catch-all for anything that doesn’t meet the first six categories. While most recyclable plastics are known as thermoplastics, meaning that they can be melted down, this category contains many thermosets which cannot be melted down once they have been cured.
It is important to remember that “recycle” is the third of the 3 R’s for a reason. Your biggest impact comes from first “Reducing” by avoiding excessive packaging and consumption of disposable products, by “Reusing” by using packaging (such as water bottles and food containers) more than once, and lastly by “Recycling” what you haven’t been able to reduce and reuse. Also keep in mind that a working recycling system depends not only on a supply of plastic waste but also on a demand for recycled plastics. So make sure that you look for products and packaging for recycled plastic content.
Thanks for your question, Barb! Keep them coming!

Pablo Päster

Sustainability Engineer
www.AskPablo.org
Additional Resources:
http://www.coopamerica.org/pubs/caq/articles/Fall2007/recyclingFAQ.cfm#biodegradable
http://en.wikipedia.org/wiki/Resin_identification_code
http://en.wikipedia.org/wiki/Plastic_recycling
http://www.valcorerecycling.org/affair/archives/2002-08-04.htm
http://ngm.nationalgeographic.com/ngm/2008-01/high-tech-trash/recycling-text.html