"Breakdown of compostable packaging in seawater is positive side effect, but not the main goal"

06-05-2019 – Last week the university of Plymouth published a study stating that compostable packages do not perish and therefore producers of the packaging are making claims that are not being fulfilled. Since all of the plastic we use in our packaging facility are compostable – they are labeled as such and should be treated as compostable – we decided to take a closer look at the study to see what it is really about. What we discovered is that the study is ignoring the way in which the compostable packages should be composted. It is a positive side effect that the compostable packaging breaks down by simply putting it in seawater, but not the main goal.

The study

In the study various types of bioplastics were tested such as biodegradable, oxo-biodegradable and compostable packaging, but also a conventional plastic carrier bag. The packages were tested in three natural environments: open air, buried in the ground and submerged in seawater. In addition, the packaging has also been tested in controlled laboratory conditions. The researchers conclude that none of the packages break down (completely) in the air and in the ground, the compostable packaging was the only packaging that completely disappeared in the seawater.

Why the study is not valid

Labelling plastic packaging as compostable with the EN 13432 standard does not mean it decays simply by putting it in the ground or throwing it into the sea. Our supplier of our compostable plastics states: “Composting is only possible in an industrial installation where an ideal, controlled environment is created with regard to temperature and humidity. The fact that the compostable packaging in the research eventually also decays in seawater is a positive side effect, but the standard has not been established for this”.

Not only focus at end-of-life, also look at the raw materials

Of course the waste problem is covered in the news the most because it is also the most visible. As a result, it is forgotten that compostable packaging is often made from renewable resources. This fact alone should be a reason to use compostable packaging as much as possible.