Report Test to fail –
Report Test to fail – or fail to test? Faulty test design and questionable composting conditions lead to a foreseeable failure of the DUH experiment The Deutsche Umwelthilfe (Environmental Action Germany – DUH) invited the press in Mid-October, including bioplastics MAGAZINE, for what they called “a field test” (Praxistest). Under the title “Is ’compostable‘ bioplastic really degradable?” a field test was scheduled to start on October 12 th , 2022 in an industrial composting plant in Swisttal, Germany. bioplastics MAGAZINE participated in this first event and witnessed the preparation of some experimental bags to be buried in one of the huge compost heaps of the composting plant. Some bags used for the trial had been prepared before meeting the media representatives on site. Fresh yard clippings were mixed with virgin, unused biowaste collection bags, coffee capsules, plates, cutlery, candy bar wrappers, and a sneaker marketed as biodegradable. The first doubts that we had about the bioplastics samples were that unused products were chosen for the experiment. When asked about the use of empty, mint condition, waste bags and unused coffee/tea capsules that had not been exposed to heat, pressure, or water the response was: “Because, if a product is marketed as biodegradable/ compostable on the packaging it should be compostable as it comes out of the retail box”. Oliver Ehlert of DIN CERTCO (Berlin, Germany), a recognized certifying institute, comments: “Using products such as certified compostable biowaste bags and coffee capsules in unused condition neither corresponds to reality nor to the test criteria (as described in e.g. DIN EN 13432). Only biowaste bags filled with organic household waste or coffee capsules filled with brewed coffee residues are in line with real consumer behaviour”. The samples and yard clippings were packed in orangecoloured potato sacks, a method that would also be used by BASF, for example, as a spokesperson of the DUH pointed out. These sacks, closed with cable ties, were buried in one of the huge compost heaps and marked with coloured flags in order to easily find them again at the end of the test period. The end of the field test was scheduled for the 2 nd of November, just three weeks later. bioplastics MAGAZINE was invited and participated in this second date too. To put this timeframe into perspective to the certification that this experiment was supposedly testing, “the usual certifications for industrial compostability in Germany require composting after 12 and 6 weeks respectively. This test provided for a rotting time of only 3 weeks. As a rule, it is hardly possible to achieve sufficient decomposition results in such a short time interval”, Ehlert explained. The test conditions were, therefore, in the best-case scenario half as long as the certification requires and in worst-case one fourth of the time. 44 bioplastics MAGAZINE [06/22] Vol. 17
By: By Alex and Michael Thielen Opinion Predictions of DUH oracles and hard realities of compost As pointed out by Ehlert, the test had little hope to be successful – depending on how you define success that is. The DUH seemed to have jumped the gun regarding the predictable failure (or success?) as they proclaimed the test a failure on the 31 st of October (two days before digging out and examining the test samples) stating (in German): “Our bioplastics experiment has shown: Statements about the degradation of bioplastics are not to be trusted. Even in industrial composting plants, many plastic products marketed as biodegradable do not degrade without leaving residues and pollute the compost”. ([1] shows the version after the test). It has been a while since we were involved in the academic processes of scientific testing but, usually, you don’t make conclusions before you have even seen the results. Another aspect that makes this test rather dubious is the lack of one or more control groups. This is no attempt to compare apples with oranges of course, but what about comparing PLA with oranges or other normal biowaste products that are difficult to compost? However, there is no arguing with the past – we have to deal with the results that we actually have, so let’s look at these failed test objects. A closer look at the photographs we took on the 2 nd of November very clearly reveals a couple of things: 1. The timeframe for such an experiment is indeed much too short, and 2. compostable plastic products do begin to biodegrade. Thus, to really nobody’s surprise, after three weeks the bioplastics products did not turn into compost. But let’s not jump to any hasty conclusions just yet, we wouldn’t want to appear biased when analysing the results of an experiment. As it turns out we do have a control group after all, kind of at least. While this seems not originally intended for this purpose, we should look at all available data – let’s look at regularly accepted biowaste used in this experiment, i.e. yard clippings. Looking at the before and after photos from the yard clippings, you can see that the leaves and twigs are, well, still leaves and twigs, albeit a bit more on the brown side. This suggests that they are en route to decompose but are nowhere near what constitutes proper compost. If leaves and twigs don’t properly break down in three weeks, then what are we even talking about here? Biowaste-bag before … ... and after 3 weeks Yardclippings before… ... and after 3 weeks bioplastics MAGAZINE [06/22] Vol. 17 45
