Biodegradation in practice

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 those in the tests. For example, OK compost and EN 13432 are tested at temperatures around 60°C which greatly facilitates the composting process so that it does not ensure that the same happens in a natural environment. Therefore, we test all our materials directly in nature and use only the materials that allow the fastest possible biodegradation of dog waste bags there.

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 biodegradability is the 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. This is not specifically covered by the EN 13432 standard, but can be ensured by additional certificates. For example the “OK compost HOME” certificate is widely used (comparability), consistent with the EN 13432 standard and is tested under local temperature conditions (20-30°C) by Vinçotte or DIN Certco.

OK compost

All OK compost certified materials comply with the EN 13432 standard. Under industrial compost conditions (at temperatures around 60-70°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 TSP bioplastic has attained the OK compost HOME certificate with a thickness of more than 60 μm. Our TSP biodegradable dog waste bags, however, only have a thickness of 18 microns, so less than a third of that thickness. Thus, the biodegradation proceeds in a fraction of the estimated time.

Note: The temperature in the tests are above the average temperature in Germany and microorganisms are more abundant, thus, the biodegradation is faster than in nature. Nevertheless, in our view, the OK compost HOME certificate is the best indicator that biodegradation works in nature as well (at a considerable speed).

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 “d2w” or “epi” 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.

The European Parliament writes:
“Oxo-biodegradable bags also decompose into microplastics that are harmful to the environment. The European Commission will investigate whether there are ways to limit the use of oxo-biodegradable bags.”

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.

*Source: Technische Biopolymere (Endres & Siebert-Raths 2009)