Researchers from the project Wasser 3.0 at the University of Koblenz-Landau have made a breakthrough in the development of a process for the removal of nano- and microplastics from the water.


First successful pilot run in EW Landau sewage treatment plant


Since 2012 the team has been researching around Jun.-Prof. Dr. Katrin Schuhen a new approach to the removal of anthropogenic stressors from the water. In addition to the removal of drugs and pharmaceutical residues (so-called reactive organic-chemical stressors), the scientists have been working intensively since 2015 on the elimination of so-called inert organic-chemical stressors. These are compounds which, for long periods of degradation, linger very long in the ecosystem and damage it. Representatives of this group are plastic particles, which are also known as nano- or microplastics.


“Polymers and their products govern the world”


Production volumes in the plastics industry have risen steadily from 1.5 million tons of polymers in 1950 to 322 million tons in 2015, and the trend continues to rise. The bulk of the plastic was processed into packaging in 2015 – in Germany it is 35 percent of total production. But also in the construction industry, with a share of 24 percent, much “plastic” is needed. The remaining polymer needs are divided into electronics, furniture, household goods, agriculture, medicine and much more. In 2012, Europe accounted for 25.2 million tons of plastic waste – of which 9.6 were deposited and 15.6 million tons recovered. Approximately 42 percent of these recovered wastes were recycled and approximately 57 percent burned for energy recovery. But this is only the directly visible “plastic waste”, which is considered in the recycling process. What about the unreactive (inert) organic chemical compounds and their degradation products when they enter the ecosystem?


Nano- and microplastics are a global problem


The primary microplastics are plastic particles, which are already less than 5 mm in their release into the environment. If these are further degraded, nanoparticles can be formed. The name Nano refers to its size, which is typically 1 to 100 nanometers, which corresponds to a billionth of a meter (10-9 m).


A portion of the primary microplastic cargo originates from cosmetics industry products, e.g. Toothpaste or peeling. Another part enters the water through the usual washing process. During washing, the mechanical stress of the laundry releases fibers and particles which enter the waste water. In the sewage plant, the waste water is standardized in three stages. For many substances, this means the end station. For reduction of organic and chemical compounds (drugs and their degradation products), or also for nano- and microplastics, there is little or no reduction.


As a result, sewage plants between 10 and 60 grams of microfibers are discharged into the water per day. Because the animals (eg fish) cannot distinguish between food and plastic, these small particles arrive at the table over the food chain at a later date. There is time to act.


How can these inputs be reduced to the environment?


Wastewater treatment plant of EW Landau

The first efficient process for the removal of nano- and microplastics from sewage water has now been successfully tested by the AG Organic and Ecological Chemistry of the University of Koblenz-Landau in a pilot experiment in the sewage treatment plant of EW Landau. As already for the removal of the reactive organic stressors, the team Wasser 3.0 around Jun.-Prof. Dr. Katrin Schuhen uses inorganic-organic hybrid silica gels.


Together with the company abcr GmbH in Karlsruhe and the Zahnen Technik GmbH in Arzfeld, the team of researchers and developers from synthetic chemists, environmental scientists and wastewater technicians work on adaptable systems that bind pollutants in a water-induced reaction and because of the resulting particle growth the entire set of undesired particles is simple Detachable. And this with success, as the first experiments on a large scale show.


Also in the area of social enlightenment the researchers take a leadership role. Through their microplastic campaign, many people are currently being informed and sensitized. Research, development, education and communication from a single source, which promises not only Jun.-Prof. Dr. Katrin Schuhen, but she has also successfully implemented this for many years.