A February study from NatureWorks on the recyclability of its bio-based polymers has raised the ire of a leading PET container recovery group, while the U.S. government may increase efforts to label bottles as bio-based.

            With polylactic acid (PLA) continuing to gain market traction in plastic bottles and injection molding applications, issues with recycling have also bubbled to the surface. At the center of the controvery is a February study from Minnetonka, MN-based NatureWorks that demonstrated that plant-made PLA materials can be automatically sorted from PET and other materials in the recycling stream and does not contaminate the recycled PET (RPET) extrusion process.

            The study, in conjunction with PLA bottle supplier Primo Water, was monitored by independent consultant Plastic Forming Enterprises and included some of the leading sorting technologies.

            However, while the study concluded that no technological barriers would prevent the sorting out of PLA from petroleum-based plastics, critics have questioned those results. The latest is the National Association of PET Container Resources (NAPCOR): the Sonoma, CA-based PET recycling advocates said in late July that mixing PLA materials with PET in the recycling stream would hike costs and could jeopardize the viability of current recycling systems.

            According to the group, adding near infrared (NIR) sorting systems like those used in NatureWorks’ study require an investment of $200,000 or more. With few markets for recycled PLA material, not only would the investment bring little return but it would require most PLA material be directed to a landfill, said NAPCOR executive director Dennis Sabourin. “When all is said and done, the volumes of PLA that can be separated out at this time are relatively low and do not make up the critical mass required for a viable reclamation business model,” he said.

            NAPCOR technical director Mike Schedler likened it to mixing ceramic materials in glass recycling. While ceramics can also be sorted, no viable market exists to make it worthwhile.

            The Association of Postconsumer Plastic Recyclers (APR) also has said PLA needs to be separated from PET before recycling begins so as not to contaminate the waste stream.

On the other side of the coin, England-based Waste & Resources Action Programme (WRAP) also performed a study that found NIR systems can effectively remove PLA from other resins.

Meanwhile, the U.S. Department of Agriculture (USDA) is moving ahead with plans to label bio-based products (those made from plants) with a special “BioPreferred” label. Recently, the USDA has focused efforts on labeling bio-based bottles made from PLA and other plant-based materials so recyclers can be alerted when they are entering the recycling stream and ensure that they are not mixed with containers from traditional resins.

The BioPreferred labeling system could be launched as soon as early 2010, once public comment is received.