PLA bioplastic misconceptions
Why is PLA misunderstood?
Bioplastic misconceptions have been detrimental to the compost industry. Hundreds of millions of dollars of public money have been invested in plastic recycling (the COVID-19 Response and Recovery Fund (2020): $100 million to improve recycling infrastructure, the Plastics Innovation Fund: $50 million (2022) yet as of January 2025, reported by Eunomia, Aotearoa, New Zealand’s kerbside recycling rate [household and commercial] is estimated at only 27%.
This imbalance reflects how the plastics industry and large waste management companies continue to benefit from national recycling subsidies, which reduce investment opportunities for composting and other landfill diversion initiatives. Discovered in the 1930s, but only recently becoming popular and commercialised at scale, PLA is a solution to petrochemical plastic. Here we look at the common misconceptions, to gain an understanding why councils, and some composters hold the belief that bioplastics are ‘contaminants’.
Commonly held belief #1: Bioplastics are greenwashing
Reality: Bioplastics are designed for recovery with food scraps. The European compostable standard EN 13432 was developed in response to the European Packaging and Packaging Waste Directive 94/62/CE with the objective of seeing packaging recoverable through composting and biodegradation. In Europe, mandatory organics collections and a growing composting facility network are supported by policies that enable certified compostable plastics to be managed effectively.
READ: Compostable materials in the real world: Scion x WasteMINZ
Commonly held belief #2: Compost facilities don’t accept PLA
Reality: PLA is biodegradable and compostable. Compostability describes the property of being biodegradable under industrial conditions (e.g., temperature, inoculum, humidity). These are standards. Certified compostable PLA products must disintegrate after 12 weeks. Complete biodegradation must occur after 6 months in accordance with EN 13432 (and other standards based on the European standard), leaving no distinguishable remnants or toxic residues behind.
Where compost facilities meet or exceed standards, the likelihood of residual material derived is minimised or completely avoided. When composters do not compost to standard, then you see residual materials. There are no industry standards for composters in NZ, so where we have packaging certified to global standards, not all industrial facilities reach 55 to 60°C or have cycles of six to nine months.
Such facilities cannot accept certified compostable products because the required conditions to achieve complete biodegradation of PLA are not met. A six to nine-month cycle economically might not be feasible. Some facilities use a six-week cycle!
Commonly held belief #3: PLA is not compostable
Reality: Certified compostable packaging is designed for circularity.
Compostable plastics that are tested and certified according to the European standards for industrial composting EN 13432 (for packaging) or EN 14995 (for plastic materials in general) and equivalent ASTM D6400 and AS 4736 fulfil the technical criteria to be treated in industrial composting plants. These plants provide controlled conditions, i.e. controlled temperatures, humidity, aeration, etc., for a quick and safe composting process.
EN 13432 requires compostable plastics to disintegrate after 12 weeks and completely biodegrade after six months. That means that 90 per cent or more of the plastic material will have been converted to CO2. The remaining share is converted into water and biomass – i.e. valuable compost.
READ: Plastic recycling was never going to work, and the industry knew it
Commonly held belief #4: There are no standards for compostability
Reality: There is no national standard but there are international standards recognised by the Ministry for the Environment. These standards are referenced in government documents, including: “A guide for selecting compostable products in Aotearoa, New Zealand.” The compostability of a product is certified through certification bodies to either industrial or home compostability standards.
Table: A guide for selecting compostable products in Aotearoa, New Zealand. Drafted by The University of Auckland for the Ministry for the Environment.
Commonly held belief #5: Bioplastics contaminate compost products with toxic substances
Compostable bioplastics tested and certified according to the European standard for industrial composting EN 13432 (and equivalent standards) are required to disintegrate after 12 weeks and completely biodegrade after six months. That means that 90 per cent or more of the bioplastic material will have been converted to CO2.
The remaining share is converted into water and biomass, which no longer contains any bioplastic. EN 13432 includes toxicity testing (on final products) which determines whether material residuals of composting show any inhibition on plant growth or survival of soil fauna. They also test for PFAS with the universally accepted 100 ppm limit for no intentionally added PFAS.
As a side note, Australia has recognised they need to review their ‘Compost Order’ which helps composters determine inputs because when it was created, plastic contamination was petrochemical, not 100% biobased which are two very different things. A national compost order, like Australia’s, would create the confidence required to scale, accelerating the acceptance of compostables and direct investment into the right infrastructure.
READ: Compostability standards, circularity and the unrealised potential for compostable packaging
Commonly held belief #6: Bioplastic production competes with food production
Reality: The feedstock currently used for the production of bioplastics relies on only about 0.013 per cent of the global agricultural area – compared to 97 per cent of the area, which is used for the production of food and feed. This clearly demonstrates that there is no competition between food/feed and industrial production.
Is your business ready to shift away from petrochemical plastics?
In working towards a circular economy, all material waste streams would become visible and valuable. In regard to bioplastics and other certified compostable packaging, the value of packaging recovered with food scraps is transformed, composted and returned to the community in the form of compost. Cities would use this compost for local agriculture, urban farming, public parks and gardens. Composting is an industry that thrives in open source yet is industrially scalable. For example, community (urban farms) or industrial (large waste management companies).
We supply PLA products formulated from corn, certified industrial to the ASTM D6400, AS 4736 and EN 13432 standards for industrial composting.
Interested in exploring PLA for your business? Get in touch by emailing hello@ecoware.co.nz
