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Tackling End-of-Life Issues for Bio Plastics

Presidio Economics | Tuesday May 3rd, 2011 | 2 Comments

This post is part of a blogging series by economics students at the Presidio Graduate School’s MBA program. You can follow along here.

By Lindsey Wedewer

Bio-based plastics have the potential to be a real game-changer in the world of sustainability. Alternatives to petroleum-based plastics have been springing up all over the world in the last several years. One of the most widespread and promising materials emerging is polylactide, or PLA, which is made from plant-based feedstocks such as corn, rice, sweet potato and sugar beet. PLA can be composted or completely reused, and the production process is cleaner than that of traditional plastic. PLA has broad implications for sustainability, as it has the potential to eliminate the need to utilize petroleum – a finite, non-renewable resource – for plastics, and avoids the post-consumer accumulation problems related to conventional plastics. PLA is being accepted in a number of industries, including packaging, automotive, medicine and textiles, though the production volume in the US is still low compared to that of its petro-based counterparts.

Although PLA is manufactured with two end-of-life options in mind, the material rarely meets its intended ends. There are infrastructural limitations to both composting and recycling which create an unfortunate end-of-life dilemma for PLA – even though products may be disposed of in a recycling or composting bin, they still have a chance of being landfilled. This presents a problem for PLA producers – without supportive composting and recycling infrastructures, a biodegradable and recyclable product is a difficult sell.

Although PLA readily biodegrades in a controlled setting such as a commercial composting facility, few of these facilities currently accept biodegradable plastics. Those that do often have rigid specifications for the material they will accept. For example, Cedar Grove Composting, the only facility of its kind in Seattle, requires that biodegradable materials be tested and become certified before they will be accepted as compost. Oftentimes, when PLA does end up in composting streams, it is extracted, due to its similar appearance to traditional plastic.

Even more efficient than composting, PLA can be recycled through a chemical conversion process, returning the post-consumer product to its base material of lactic acid. This allows it to be reproduced into PLA with the same properties as its virgin predecessor. Although the potential here to create a cradle-to-cradle scenario is great, there are no widespread means in the US to collect, sort or recycle PLA. Again, PLA can look quite similar to conventional plastics and since 70% of recycling is still sorted by hand, a hand-sorter is not necessarily able to identify the differences. Thus, the sorting of PLA requires expensive near infrared technology to properly differentiate it in a recycling station. Although some recycling centers are equipped with this technology, others are not and adopting it would require a significant investment.  At the end of the day, recycling facilities will not start a new material collection or invest in any new technologies unless there is consistent volume to justify it, and that critical volume of PLA has yet to be reached.

Thus, we find ourselves in a “catch-22.” Composting facilities are not seeing enough post-consumer PLA volume to alter their practices and similarly, recycling centers are waiting for PLA volume to increase so they can rationalize collection. Meanwhile, bioplastics producers are hoping for improved disposal infrastructures so they can tout the positive end-of-life options related to their products in a meaningful way. This would attract business and lead to a subsequent increase in the volume of post-consumer PLA.

Although PLA has enormous potential to succeed in the US market as an alternative to traditional plastics, the end-of-life dilemma remains a looming obstacle that will need to be addressed before its true cradle-to-cradle nature can be realized.


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Categorized: Eco Products|

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  • http://www.ecosafezerowaste.com Phil Ragan

    End of Life for rigid PLA products is a topic that is timely and one which EcoSafe is investigating for some of our closed loop projects.

    PLA has value as a compostable product for single use applications where the product is a part of the waste from the food service industry and where “in-use” the products are likely to become contaminated with food.
    Realistically, modern in-vessel composting systems such as that used at Cedar Grove are designed to compost food scraps and green waste in time frames as short as 40 to 60 days. The resulting commercial product, compost, is a a natural organic soil supplement so necessary for the revitalization of our soils. Soils that have been devastatingly depleted through decades of use of chemical fertilizers.

    Rigid PLA products such as bottles, pens and car parts would have a high value in the the recycling stream but with the lack of infrastructure confuse consumers and one could argue are are a waste of time and energy.

    The good news in this story is that with their introduction Recyclers are forced to consider solutions for resource recovery of a renewable resource with a relatively high value when compared to the current prices for petroleum based PET.

    In our messages to the marketplace, let’s not confuse the benefits from the use of sustainable natural resources with how we recover and reuse the resin from the product at the end of the products useful life.

    Bio-resins such as PLA have value as a renewable “recyclable” product but should NOT be promoted as “compostable”where they a dreaded contaminant in the finished compost. The higher and best use for these products is gained through recycling and reuse of the resin.

  • http://www.ecoramblings.com Luke

    Thanks for the post Lindsey. There are actually a very large number of composting facilities in the US that accept PLA and other bioplastics (see http://www.findacomposter.com). I look forward to the day when more exist in more places, but there are currently a couple hundred across the country.

    Also, Cedar Grove is really the only facility in the country with their own bioplastic requirements. All other facilities will accept a product if it has a BPI (Biodegradable Products Institute) certification which also means it passes ASTM D6400 and D6868.

    I don’t see recyclers being capable of collecting PLA anytime soon. The real answer is more composting facilities, but those are coming along nicely. Waste Management just invested tens of millions of dollars in a couple organics recycling facilities.

    Lastly, there is another facility in Seattle for those people interested. It’s called Silver Springs.