What are microplastics?
Microplastics are polymer particles with a size of less than 5 mm. These particles are either deliberately used in different products or are caused by abrasion or erosion of bigger plastic products. Primary microplastics are synthetic micropolymers which are for example used in many hygiene products as peeling particles, as binder or filler materials. After use of the product these microplastics are discharged into the water cycle and thus into our food chain. Secondary microplastics are microplastics which result from degradation or wear and tear of larger plastic parts. Some examples are disposables from the packaging industry, wear of tires or textile fibers from functional wear.
Why are microplastics dangerous?
Microplastics are already known to cause environmental damage. Via our waste water and the water cycle microplastics enter the food chain. It has been proven that microplastics accumulate in the human body. But it is still not known which long term effects have to be expected for humans and the environment. For example, in birds it has been observed that microplastics accumulate in the stomach and suppress the sensation of hunger. Also mechanical injuries in the gastrointestinal tract of birds as well as inflammations due to undigested particles have been observed. Within another study on mussels (My-tilus edulis) it has been demonstrated that resorbed microplastics cause inflammatory reactions in the digestive tract.
How many microplastic particles are in our water?
Current estimations suggest that approximately 140 million tons of plastic particles have been discharged into the sea. The Alfred-Wegener-Institute investigated in a study how many particles with a size of less than 500 µm cannot be filtered out of the water by a typical sewage plant. According to this study more than 700 particles per cubic meter are not being retained which amounts to 5.3 billion particles per year. It is even more critical that many of these particles are only few micrometers in size.
Why do we need new filters for microplastics?
All kinds of microplastics, regardless whether primary or secondary, that are discharged into our wastewater and subjected to wastewater treatment cannot be filtered out sufficiently by the sewage plants. Therefore microplastics are causing increasing problems in the environment and jeopardize the health of all creatures. Filters that can be used for these small particles do already exist. However, these filters themselves are disposables meaning they have to be replaced by new filters and disposed of after a certain time. The here newly developed filter is based on the cyclone filter which is self-purifying and therefore can be used over a long period.