They want to reuse sewage sludge for cars and medicine
In East Saxony and Brandenburg, several wastewater disposal companies are joining forces to recycle sewage. This is planned.
Jens Meier-Klodt, Heike Herrmann, Karsten Horn, Marten Eger and Gerd Weber (from left to right) want to build the third phosphorus recycling plant for sewage sludge in Germany in East Saxony and South Brandenburg. © Cooperation Lausitzer Abwasser Recycling GmbH
More is made from sludge: In East Saxony and Brandenburg, three sewage companies are making sewage sludge usable for cars and medicine. To this end, they have now joined forces and founded the inter-municipal company “KLAR” – the long version is called “Kooperation Lausitzer Abwasser Recycling GmbH”. They are planning a plant to reuse the phosphorus contained in sewage sludge. In the European Union, it is considered a critical raw material that is rare and finite.
Germany is particularly dependent on Morocco and the Western Sahara. Scientists also assume that global phosphorus production will peak in the 2030s. The problem: without phosphorus, plants cannot grow.
Precious phosphorus to be reused
And the precious substance is not only used as a fertilizer. Phosphoric acid is also needed in the animal feed industry, pharmaceutical production and the automotive industry. The latter needs the agent as corrosion protection. The cars are soaked in phosphoric acid before being painted.
That is why the three wastewater disposal companies now want to take the lead and extract phosphoric acid from sewage sludge. The two million tons of sewage sludge that are fished out of Germany’s wastewater every year contain around 60,000 tons of phosphorus. “This is also about independence from international producers,” explains Karsten Horn, Managing Director of KLAR.
First phosphorus recycler is insolvent
The recycling plant is optimistically scheduled to open by 2030. There are currently two such plants in Germany, one in Magdeburg and one in Hamburg, says Karsten Horn. However, the phosphorus recycler Seraplant in Magdeburg has filed for bankruptcy.
That is why they want to follow the example of the Hamburg-based company and use the so-called “Tetra-Phos process”. In this process, the pollutants in the sewage sludge are first “eliminated” by incineration. In the second part, phosphoric acid is filtered out of the sewage sludge ash. This also produces gypsum and mineral sand, which can be used in concrete production or road construction.
Law forces waste disposal companies to act
In order to finance the hall, “KLAR” is looking for more wastewater associations from southeast Brandenburg and eastern Saxony. There are currently three of them: the Oderaue drinking water and wastewater association, the FWA Frankfurter Wasser- und Abwassergesellschaft mbH and the LWG Lausitzer Wasser GmbH. The LWG alone disposes of wastewater for more than 100,000 Cottbus residents.
The reason for the recycling plant is also a sewage sludge directive that was changed in 2017. The law requires phosphorus to be recovered from sewage sludge. Starting in 2029, the operators of wastewater treatment plants are obliged to implement the directive depending on their capacity utilization. “The comparatively small-scale structure of wastewater disposal capacities in the Brandenburg area is a rather difficult environment for possible large-scale private investment projects, unlike in Berlin, for example,” explains Gerd Weber, Managing Director of the FWA. This is why many people need to pull together.
Microplastics and heavy metals in the blood
There is another reason for the recycling plant: “Sewage sludge is a pollutant sink,” explains Karsten Horn. “In fact, in my view, it is problematic to explain to citizens why we in the municipalities use a lot of resources to clean our wastewater, only to then return the pollutants deposited in the sewage sludge, such as heavy metals, microplastics and drug residues or even resistant germs, to the water cycle via the detour of agricultural application,” he says. This is because the sewage sludge is brought to the fields. “Sooner or later, the pollutants end up in everyone’s blood,” says Horn. Organic farmers and conventional farmers are already no longer demanding sewage sludge in large quantities. The recycling plant therefore offers an alternative to recycle the sewage. In addition, restrictions on the removal of sludge will also apply to agriculture from 2029.
Horn cannot yet say how much the plant will cost. That depends on how many municipal wastewater companies join and how big the plant will be. A financing plan is to be drawn up in mid-2025 to start construction.
