The TH Lübeck, Laboratory for urban water management and waste technology, has been operating a pilot and training treatment plant (VAK) on the site of the municipal sewage treatment plant in Reinfeld since 2005. The aim of the plant is, among other things, to test new technologies that enable improved and more efficient cleaning of (municipal) waste water. The VAK also serves to train young academics in the field of technical water protection within the framework of internships, bachelor’s/master’s theses and R&D projects.
Trace substances, microplastics, multi-resistant germs
The plant technology currently available at the VAK (activated sludge process) corresponds to the state of the art in the 1990s. It primarily allows the minimization of the nutrient content to protect the water bodies against eutrophication or an acute oxygen deficit. In recent years, however, more and more extensive problems have been identified in the professional world with regard to the handling of waste water and the necessary cleaning performance. This includes the following topics in particular:
- The retention of trace substances that have not yet been fully retained in municipal wastewater treatment and which have been shown to have a negative impact on ecosystems in water bodies. The trace substances include, for example, pesticides, heavy metals, medicines or cleaning agents.
- The retention of microplastics, which can be problematic for the aquatic environment as a source of plasticizers (phthalates, etc.) or as carriers of other trace substances that accumulate on the surface of the particles.
- The retention of (multi-resistant) germs for which no or only a few antibiotics are available and which are currently being introduced into water bodies to a certain extent through sewage treatment plants.
“It is extremely important that we hold back these substances, because otherwise our sewage system would be an open system. This means that all substances that are drained from the city can then potentially get into the waters,” says Prof. Matthias Grottker, head of the laboratory for urban water management at the Lübeck University of Applied Sciences.
For the targeted retention of trace substances, municipal sewage treatment plants in Baden-Württemberg and North Rhine-Westphalia, for example, have already been expanded with processes of the so-called 4th cleaning stage, which are necessary to remove trace substances from the wastewater in a targeted manner. These include activated carbon treatment and ozonation. Approaches to a solution such as membrane processes or process combinations of the aforementioned process technologies have not yet been implemented in municipal sewage treatment plants. Depending on the process selected, microplastic particles and/or (multi-resistant) germs are also removed from the wastewater.
New technology for future-oriented wastewater treatment
Against this background, the state of Schleswig-Holstein has given the Lübeck University of Applied Sciences a grant notice in order to expand the existing VAK with various modules for the 4th cleaning stage. The planned investment enables modern processing of wastewater technology issues and is therefore forward-looking for wastewater treatment in Schleswig-Holstein in the coming decades. The VAK sees itself as the central contact point for questions regarding the 4th cleaning stage at municipal sewage treatment plants in the state of Schleswig-Holstein. Furthermore, the sewage treatment plant operators in Schleswig-Holstein can get to know the new innovative processes or process combinations and learn how to use the technology. In addition, the mobile solution at the VAK can be used to test the individual processes or process combinations at municipal sewage treatment plants in Schleswig-Holstein and to test them with their specific wastewater composition. This primarily applies to sewage treatment plants that intend to retrofit their sewage treatment plant with a 4th cleaning stage. The sewage treatment plant operators can be supported by the VAK to the extent that the most effective and economical process solution can be found.
The funding of EUR 700,000 for the expansion of the VAK was approved from EU funds from the reconstruction fund (EURI), which were made available via the Schleswig-Holstein state program for rural development (LPLR). The approval is granted in accordance with the “Guideline for the Promotion of Wastewater Treatment Measures in Schleswig-Holstein” of October 24, 2021.