Process of biodegradation
The biodegradation of our poop bags takes place mainly by oxidation and hydrolysis. The material is processed by microorganisms such as bacteria and fungi.
Biodegradation in practice
To allow comparability all tests for certificates (OK compost / OK compost HOME) and standards (EN 13432) take place under defined standard conditions. The actual conditions in the case of littering into nature are of course always different, depending on solar radiation, humidity, temperature and especially the presence of microorganisms.
In most cases, the conditions for biodegradation of the poop bags in nature are worse than in the tests: OK compost and EN 13432 are tested at around 58 °C, which greatly facilitates degradation. That is why we additionally tested our material in our own field trial directly in nature.
Notice: The bag is filled with dog feces to create authentic test conditions – admittedly, there are more beautiful sights!
After 12 weeks there was practically just the knot left, its biodegradation takes longer as the outer layers protect the inner ones from environmental influences. In contrast to conventional plastic poop bags, after a few days the dog feces are already accessible to microorganisms with the result that the biodegradation of the feces can be done quickly.
The video showing the biodegradation of our dog waste bag was tested under good conditions – different terms can shorten or extend the time of biodegradation. Our biodegradable dog waste bags do not simply “disintegrate”, they are actively processed by microorganisms. If only a few microorganisms are present and / or if other factors such as solar radiation and moisture are missing (as it would be the case under a bridge), the bag can last there for years. This also applies to other biodegradable material such as twigs or leaves.
EN 13432
The central European standard for compostability is EN 13432, which includes four parts:
- Characterization of material composition*
- Biodegradability*
- Desintegration during biological treatment (after the composting process no polymer components should be visible anymore)*
- Effect on the quality of the resulted compost*
To reduce the negative impacts of dog waste bag littering in the environment it is crucial that the biodegradability works under central European temperature conditions. EN 13432 covers industrial composting conditions. OK compost HOME supplements this testing with defined home composting conditions at ambient temperatures of 20–30 °C.
OK compost
All OK compost certified materials comply with the EN 13432 standard. Under industrial compost conditions (at temperatures of around 58 °C) at least 90 percent of the compostable material must have been processed after 6 months.
OK compost HOME
All OK compost HOME certified materials are also compliant with the EN 13432 standard. In addition, the biodegradability is tested under home-composting conditions at temperatures around 20-30°C. Within 12 months at least 90 percent of the material must be processed. The thicker the material, the longer the biodegradation process (similar to a tree trunk compared to a branch). Our material is certified up to a nominal thickness of 63 µm – at 18 µm, our dog waste bags are considerably thinner. Enzymes act on the surface, which is why thinner material is broken down correspondingly faster.
Note: The temperature during the tests is above the average temperature in Germany and microorganisms are more abundant – degradation in nature may therefore be slower. Nevertheless, in our view and experience, OK compost HOME is a very good indicator that microorganisms also break down the material at low ambient temperatures.
Oxo dog waste bags
“Oxo” poop bags are made of ordinary plastic such as polyethylene, also called PE. Various manufacturers refer to their products as “degradable”, “biodegradable” or even “compostable” as additives such as metal salts are believed to biodegrade the plastic in combination with sun exposure – however there is only a comminution taking place, so that the material breaks down faster into microplastics and the additives are still getting into the environment.
Oxo-degradable plastics merely fragment into smaller plastic particles through oxidation and do not solve the problem of plastic entering the environment. They have been banned since 3 July 2021 (EU Directive 2019/904, Art. 5; implemented in Germany by the EWKVerbotsV).
Oxo dog waste bags can be recognized by the fact that they cannot be certified according to the EN 13432 standard and therefore are not allowed to carry any seal such as the “seedling” (Keimling), “OK compost” or “OK compost HOME” certificate. Further the material can be recognized by terms such as “oxo”.
*Source: Technische Biopolymere (Endres & Siebert-Raths 2009)