Compostability versus biodegradability
While the emphasis on compostability is clear, the word biodegradability is in the institute’s name, not compostability. This begs the question: is there a difference between the two, and if so, how do they differ?
According to the ASTM D883-23 Standard Terminology Relating to Plastics, which covers definitions of technical terms used in the plastics industry, biodegradable plastic refers to degradable plastic in which the degradation results from the action of naturally occurring microorganisms such as bacteria, fungi, and algae.
The biodegradation rate can vary depending on factors such as humidity, temperature, and the specific conditions of the environment.
On the other hand, compostability describes the environment and the general conditions in which biodegradation occurs, explained Yepsen. In other words, biodegradation can occur in multiple environments, and composting is just one of these.
“The reason our organisation has taken the broader name is because our mission encompasses other things besides compostability - but the majority of what we work on today is compostability, just due to the fact that that's where a lot of needs are around packaging, design and waste management. But yes, we also do some work on things like soil biodegradability for agricultural products, as an example of another environment in which biodegradation can occur.”
The oceans represent another environment where biodegradability is possible, but, said Yepsen, it is a very challenging environment in which to measure biodegradability in any type of repeatable way. Composting is a controlled and desired end of life for materials; they are collected and processed in a managed process. When it comes to marine biodegradability there is a great deal of variability.
“Plus, there are some practical considerations about communication with consumers,” added Truelove. If you allow a product to make a claim that it's marine biodegradable, what might that instruct the consumer to do with it? You know, there needs to be I think a clear indication of where it's supposed to go, even if it does biodegrade in a place where it's not supposed to go - like the marine environment.”
Again, that takes the discussion back to communication. How to formulate biodegradability claims on products, without implying to consumers that it is all right for them to dispose of the products in an undesired environment.
“Even if a product is technically marine biodegradable, we want to make sure that consumers know where they're supposed to put it, i.e., either in the recycling bin or the compost bin,” said Truelove.
Labelling is crucial
One important facet in communication is labelling. Labelling is a challenge in itself, raising issues such as what it should say, and more to the point, what it should not say. BPI has therefore recently been putting considerable time and effort into both identification and labelling, said Yepsen. “We’ve been working with the US Composting Council (USCC), the group that represents the composters, aiming to create agreement across the entire industry supply chain,” he said.
BPI and USCC have developed principles designed to inform policymaking about good labelling.
“What should products not be allowed to state if they're not compostable? That, too, is an important aspect. We've seen a few states in the US taking steps towards prohibiting misleading terminology or terminology that is not substantiated on product labelling - for example, suggesting that a product is generally biodegradable in any environment, even though there is no test to actually prove that,” noted Truelove.
Getting the labelling sorted promises also to be a big step towards decontaminating the compost stream, Truelove continued. Contamination is currently perhaps the major issue for composters. Fear of contamination is part of the reason why today only about 4% of all post-consumer food waste generated by Americans is sent to composters.
In fact, according to a recently released report from The Composting Consortium, a collaborative initiative led by the Center for the Circular Economy at Closed Loop Partners, kerb side organics collection in the United States has increased by 49% since 2021, yet only about 200 full-scale commercial composting facilities in the U.S. accept food waste, and even fewer that accept compostable-certified packaging. Most take yard waste only. Managing contamination can have a direct impact on a composter’s ability to sell finished compost at a specific price point, even sell it at all. Contamination in the organics stream is not a new problem, but it requires new solutions, writes the report.
“Composters want to be able to accept compostable products and all of the good food waste and organic waste that they bring. But if they can't tell the difference between a compostable product and a non-compostable product that looks very similar, and if consumers can't tell the difference at the bin, then we're going to continue to have serious contamination issues in some cases for composters, who may then decide that dealing with these contaminants is simply not worth the effort. So labelling is a big part of promoting a wider use of composting,” said Truelove.
Funding for infrastructure
Next to labelling, and at least as important, is the need for a better collection and treatment infrastructure - and financial support for these systems – to successfully promote the correct disposal of compostable plastics.
In North America, and in the United States in particular, only a minority of Americans have access to compost collection, whether kerb side or drop off. And while the activities in this space are increasing, far more investment will be required to arrive at a level similar to where recycling is.
“That’s closer to universal access. One of the mechanisms for funding that infrastructure is extended producer responsibility – EPR - which I know exists in a lot of countries across Europe. But we are now also starting to see that in North America – as most Canadian provinces have some form of EPR,” Truelove clarified.
He noted that currently, four states had already passed EPR laws, and that, over time, these laws were undergoing
changes as they spread from Europe to Canada, and then the US.
One of the big changes that BPI has fought for is the inclusion of support for compost infrastructure.
“Historically, compostable products have always had to pay into these systems, but often the money that they pay into the system goes somewhere else: it gets spent on recycling or other reduction measures. And we think it's only fair that that money should roughly proportionately go to infrastructure and processing for compost. I would argue that the spirit of EPR is to help build systems to support the safe management of all of the packaging and products that are included,” declared Truelove.
An encouraging trend can be seen in laws that specifically include funding for compost, infrastructure and education as well as representation from the compost community. This is a significant development, as many of the people working on EPR hail from a recycling background and are not familiar with the specific challenges around composting, and compost contamination.
These EPR laws have not yet been fully developed and implemented in the United States, but four states, among which California and Colorado, are in the process of doing so.
“We're seeing early needs assessments that are identifying gaps and capital investment needs for compost systems. We are seeing composters being integrated into conversations and being able to express their opinion around how these systems could help them, and these are all developments we are excited about. We think that in combination with better labelling to help with the contamination, this could start to make a true impact,” Truelove concluded.
Composting installations for the most part lack the sophisticated sorting systems used by recyclers to deal with the contamination problem. The material, mainly yard trimmings and food scraps, is very wet and dense – an environment that is challenging for the identification and sorting out contaminants. “And capital investment in these facilities tends to be significantly lower than your average recycling facility,” said Yepsen. “But we've seen some pretty cool changes in that sector, as private investments have come into the composting space. A facility in Texas has been experimenting with AI and robotics to do some front of the line sorting, but a lot of times composters may have only a pick line, to pull out the most obvious contaminants - things like glass.”
The study mentioned earlier also looked in great detail at this aspect, finding that, while ‘machinery and equipment can be useful to address contamination at different points in the composting process, but no matter what, removing contaminants is still a labour-intensive process.’ It noted that seven of the 10 composters participating in the study cited labour as a leading cost driver in their overall operations.
A robust certification programme
Perhaps the most well-known activity of BPI is its certification programme. The Institute is the leading third-party verification of ASTM standards for compostable products in North America. BPI certification enables consumers to distinguish manufacturers and brands whose products comply with scientific standards from those that do not.
Unlike TüV Austria and DinCertco in Europe, BPI is an association and therefore has a far different business model. The standards – EN 13432 and the ASTM standards for compostability - to which conformity must be demonstrated, however, are very similar, as are the test methods.
“The pass-fail criteria tend to be very similar in the standard and then a certifier adds criteria on top of the standards. This is where the differences come in, and it is something that BPI has really led the way on. For example, back in 2017, we banned the intentional use of chemicals like PFAS, and now other certifiers have also built this into their criteria,” said Yepsen.
“We also have an on-product labelling requirement. That's another pretty big distinction. So, we actually just completed a three-year rollout of our on-product labelling rules. You cannot be certified by us unless you have marked the product and the packaging. We allow it to be done by any means possible, including printing, embossing, etching.”
BPI certification is focused on North America, with some being performed in Central and South America. Yepsen: “We actively encourage companies who are trying to make a compostability claim in Europe to use a European certifier and participate in those bodies. A global system would be easier and we've had some good discussions around how to better align on that, but it's tricky. 15-20 years ago, when compostability first launched, would have been a pretty easy moment in time to establish a global system, but today, there are too many differences.”
