The treatment plant in the municipality of Althengstett treats the water produced by 18,000 inhabitants. This is a plant with an activated sludge process and nitrification/denitrification, where up to now, an iron-aluminium mixed product with the same active substance – with reference to phosphate precipitation – was in use. To demonstrate the effect of VTA Biolizer® and the savings potential associated with it, the new high-performance product was used at the plant and the results obtained were compared with previous values. The load on the plant and the dosage quantity were the same in both cases, so that it was possible to make a comparison. Oxygen transfer was increased significantly, enabling savings in the aeration system.
What can VTA Biolizer® do?
VTA Biolizer® promotes bubble equilibrium in the activated sludge stage. The gas-water contact surface and thus the level of oxygen transfer are increased. This makes the biological process more balanced and efficient, so that aeration times can be shortened or air can be blown in over a smaller section of the aeration zone. This means that up to 30% less ventilation energy is required. But that is by no means all that this brand-new high-performance product can do.
Optimisation with VTA Biolizer® also improves the sludge’s settling and thickening behaviour. This is hugely important because it also optimises the settling and thickening behaviour of the activated sludge, and thus the operational reliability of the treatment plant. All in all, VTA Biolizer® is particularly suitable for wastewater with high organic loads, as it improves the overall performance of the activated sludge stage. The values at the plant in Althengstett, which in themselves were already good, were further improved by the use of VTA Biolizer®.
The underlying mechanism Overall, smaller bubbles have a larger contact surface between air and water, improving oxygen transfer into the activated sludge. A stable process and increased degradation capacity can therefore be achieved with a lower aeration rate. Focus on quality of life Its proximity to urban centres such as Sindelfingen/Böblingen or Stuttgart is not the only thing that Althengstett, a town in the east of the district of Calw in Baden-Württemberg, has going for it. The municipality is embedded in an idyllic landscape, offering sweeping views over the northern Black Forest. It is in the Hecken- and Schlehengäu region and situated not far from the landscape conservation area of the same name. The region is characterised by agricultural use. Arable farming, pasture farming and fruit growing have produced numerous cairns of cleared fieldstones, which are overgrown with hedgerows. Cleared fieldstones are loose stones and blocks lying around fields, pastures and meadows that have been stacked up into mounds at plot boundaries before use of the land for agricultural purposes.
In the east of the district of Calw, the sloe hedges that grow on these banks are called Schlehenhecken, giving the region its name. In addition, thirty percent of the municipal area of Althengstett is forest, another hallmark of the landscape.
Neighbouring the birthplace of Hesse
Not far from Althengstett is Calw, birthplace of Hermann Hesse, the German Nobel Laureate in Literature. In his stories, Hesse often referred to the town under the name of Gerbersau. From Althengstett to Calw is about ten minutes by car. Much in this area revolves around the prominent author, whose works include ‘Demian’, ‘Steppenwolf’ and ‘The Glass Bead Game’, and music and education are also important. Among the institutions here are two secondary schools – one is indeed called the Hermann Hesse Grammar School and one is a polytechnic focusing on both tax and auditing and media and communication management.
Back in Althengstett: The Baden-Württemberg community supports this quality of life with childcare facilities for toddlers and children, as well as with secondary schools. It has twice been awarded prizes as a child and family-friendly community. The infrastructure of Althengstett, from its transport connections to its shopping facilities and a varied club life, complete the picture. Finally, there is also a multi-generational park that encourages young and old to come together. The park appeals to children from the age of three, while also offering many retreats and resting places for the older generation. Water as a theme also plays a major role here, with numerous fountains constituting important elements in the design of the park. The wastewater treatment plant also makes a significant contribution.
Field report from the VTA Group’s scientific journal “Laubfrosch”, issue 81