The „Verbund kompostierbare Produkte e.V.“ (Association for Compostable Products) welcomes the immediate correction by the press office of the University of Plymouth due to the numerous false quotes of the study results.
Based on the study results a clear difference between so-called “biodegradable”, “oxo-degradable”, conventional and certified compostable bags (according to EN 13432) could be determined. The degradation of these bags was investigated in the sea and in soil.
The author of the study, Prof. Dr. Richard Thompson, personally confirmed yesterday (May 1, 2019) that only the compostable bag was completely disintegrated in the sea and had also begun to decompose in the soil.
Certified compostable bio-waste bags have not been developed for degradation in the soil or in a marine environment. These certified bags are intended for degradation in an industrial composting plant, which is why the results shown here go well beyond the specified compostability certification. Compostable plastic products should generally not be littered into the environment in an uncontrolled manner.
Which conclusions must be drawn from this?
Products advertised as biodegradable must be certified as biodegradable in clearly defined environmental conditions. General statements on the biodegradability of products without this proof are to be regarded as dubious.
The study shows that ordinary PE bags cannot be made biodegradable by additives. PE bags, which contain these additives and are marketed as “biodegradable” or “oxo-degradable” do not degrade. Neither in composting plants (nor – as the study shows – in soil, nor in a marine environment).
ALL certified compostable plastic bags are approved for composting according to scientifically established standards (EN 13432).
The non-certified “biodegradable” or “oxo-degradable” plastic bags examined in the study are not approved for the bio-waste bin in Germany in accordance with the bio-waste ordinance (Bioabfallverordnung – BioAbfV) and are not available as bio-waste bags in retail stores.
Numerous studies have shown that the targeted use of certified compostable bio-waste bags for separate bio-waste collection makes it easier for citizens to collect bio-waste, which can significantly increase the quality and quantity of compost. The sensible use of such approved bio-waste bags – with careful municipal communication – ensures a verifiable reduction in the number of “misthrows” in the bio-waste, especially of waste bags made of conventional plastics.
Certified compostable bio-waste bags can be identified by the seedling logo or OK-Compost marks.