End of Life
As a core principle of sustainability, it is important to maintain the 4 R’s of reduce, reuse, recycle, and recover. Many biobased products can be recovered in their lifecycle via composting or recycling, although adequate composting and recycling infrastructure is still needed. To get the products where they need to go for their next phase of life is easily accomplished through appropriate labeling and education.
Consumers may be bewildered by the many descriptions of biobased products and how to treat them after use. Many believe “biobased” means that a product is biodegradable or compostable, which is not always the case, especially as many biobased products are manufactured for long-term use. For instance, some car parts are biobased but they will not degrade during the vehicle’s lifetime.
“Biodegradable” does not necessarily mean that a product is compostable, but does mean that the product willeventuallybiodegrade due to the actions of naturally occurring microorganisms. The definition of compostable includes a time frame for biodegradation and end results of the process. “Compostable” means that a product will undergo complete degradation by biological processes during composting into carbon dioxide, water, inorganic compounds at a rate consistent with other known compostable materials. Compostable products have to meet a composting standard, such as ASTM D6400 or EN 13432, and usually display a certification logo such as the Biodegradable Products Institute (BPI), Vinçotte, or BNQ logo to name a few. To counteract consumer confusion, California passed two laws, AB 1972 and AB 7071, which mandate that products cannot label their products as “biodegradable” or “compostable” unless they have met the qualifications of the ASTM standards that deem them biodegradable or compostable.
Labeling is an important aspect of biobased products since many of them resemble their petroleum counterparts. To ensure products go to their proper end of life system, they need to have distinct labeling, with colors and text, to explain the nature of the product and how it should be managed at the end of its intended use. This will ensure that compostables go to composting and recyclables can be recycled where available.
The Sustainable Biomaterials Collaborative (SBC) is addressing end-of-life concerns of biobased products by promoting proper labeling and education on what makes a product compostable. In theBioSpecs for Food Service Ware, compostability labeling is required in green lettering that is at least ¼” in height on certain products. In Seattle, Washington, the local composting facility, Cedar Grove Composting, tests products in their composting system to approve them in their facility and works with manufacturers to have Cedar Grove Approved products labeled and color coded brown. Cedar Grove also works with purchasers to make sure products that are acceptable in their composting system, or are Cedar Grove Approved, are bought.
Without the technology and infrastructure to handle discarded biobased products, bioplastics are likely to end up as trash in a landfill or incinerator rather than recovered through composting or recycling. The composting infrastructure is developing rapidly but not all parts of the country are yet served with facilities that accept food residuals, let alone compostable food service ware. Seattle and San Francisco are recognized as leaders. They are promoting adequate labeling of products for compostability and working directly with private composters to ensure products are compostable at these facilities.
While the composting infrastructure is developing, systems for recycling PLA-based bioplastics are virtually non-existent and there remain challenges to widespread implementation. There are concerns that bioproducts will contaminate existing plastics recycling systems, particularly HDPE and PET recycled streams. NatureWorks has done extensive studies evaluating the impact of its PLA on PET and HDPE recycling. Early studies focused on whether PLA bottles would harm existing plastics recycling systems and whether PLA could be sorted out from PET and other plastic bottles effectively. These studies indicated that with the proper state-of-the-art infrared optical sorting equipment, 97.5% of PLA could be removed from other plastics. NatureWorks has yet to test whether sorted post-consumer PLA can be recycled back into a usable recycled-grade PLA for remanufacturing. It has, however, explored the level of PLA contamination that HDPE and PET could handle. PLA has no effect on the color or melt index of HDPE flake at up to 2% concentration. For PET, above 1,000 ppm (0.1%), PLA will affect its haze and color, thus limiting its end-use markets. NatureWorks has long argued that the market share for PLA is too small to impact conventional recycling systems and reach these levels of contamination. Recyclers retort that NatureWorks has an obligation to ensure its green-marketed resin can be recovered for recycling and that as PLA market share grows, a system for its recycling needs to be in place. In addition to sorting PLA bottles from other plastic bottles, NatureWorks has tested chemical recycling of post-industrial PLA. It has recycled over 4 million pounds of post-industrial PLA back to its chemical constituents in order to be reused as lactic acid. NatureWorks reports that it successfully fed back chemically recycled lactic acid into their polymer reactor to make new PLA, without the use of solvents.More recently, NatureWorks is supporting a California PLA recycling pilot project, which involves a portable trailer-mounted optical sorting system that can be taken to recycling processing facilities. The project aims to develop an understanding of the business base for recycling PLA as well as an understanding of where and how much Ingeo PLA is popping up at recycling facilities. BioCor is a US company (of which NatureWorks is a minority shareholder) that offers a recycling outlet for small or large quantities of post-consumer PLA. BioCor acts as a broker, buying the scrap PLA and selling it to an existing re-hydrolyser in Wisconsin to chemically break down the bioresin to its component lactic acid base.
The challenges with recycling PLA bottles has, in part, led Coca Cola and Pepsi Cola to avoid their use. Instead, both corporations have developed and introduced a new generation of PET biobased bottles. PET is plastic resin #1, which is the resin with the highest recycling level. Coca Cola’s “PlantBottle” is partially derived from sugarcane-based ethanol. Pepsi’s bottle is made from switch grass, pine bark, corn husks and other materials. Ultimately, Pepsi reports that it plans to also use orange peels, oat hulls, potato scraps and other leftovers from its food business. One important benefit of these PET biobased bottles is that they are completely compatible with the existing PET recycling infrastructure.
Organic Compost Qualification
Composters who sell their compost products to organic farmers may not accept biobased plastics, as these materials are deemed synthetic and unacceptable by the National Organics Program (NOP) and National Organic Standards Board (NOSB). Many composters supply their compost to organic farmers, which would be forbidden if they made compost from compostable products. This is because the chemical processes required to produce PLA and other compostable plastics categorize these plastics as “synthetics” under the NOP’s definition. In addition, some of the additives may be petroleum-based.1
The Biodegradable Products Institute will be seeking NOP approval for the use of biobased plastics that meet ASTM D6400 and ASTM D6868 for use in composting operations selling to organic growers. While this is effort is moving forward, suppliers of compostable plastic materials understand that composters will be bound by the restrictions placed on them by certification organizations.
1The NOP defines synthetics as “A substance that is formulated or manufactured by a chemical process or by a process that chemically changes a substance extracted from naturally occurring plant, animal, or mineral sources, except that such term shall not apply to substances created by naturally occurring biological processes.” This matter is currently under petition, especially since many petroleum-based preservatives found in food are allowed in organic compost feedstock.