"Our aim is to be the best value long-distance water supply company in Germany, offering the best quality drinking water while ensuring a reliable supply and the sustainable use of resources.” That is the guiding principle of the Landeswasserversorgung Baden-Württemberg.
Founded in 1912, the joint body provides 90 million cubic meters of drinking water every year to around 250 towns, cities and communities in Baden-Württemberg and Bavaria. Some 3 million residents are supplied through a 775 km long pipeline network, from the two water works in Langenau and Dischingen.
Danube water, provided efficiently and sustainably
The Langenau plant is one of the largest and most state-of-the-art water treatment plants in Europe. It went into operation in 1973 on the "Sptzigen Berg" on the edge of the Donauried, a river landscape around the Danube in western Bavaria between Neu-Ulm and Donauwörth. It was extended in 2014 and got a new ground water filtration system, with pneumatic automation technology from Festo.
The water, which is taken from the River Danube at Leipheim, is converted to drinking water through a multi-level process. Following three preliminary purification steps, a multi-media filtration system removes any remaining suspended particles. The subsequent activated carbon filtration eliminates organic contaminants, even in the smallest concentrations. The automation technology from Festo controls the water flow using energy-efficient pneumatically operated process valves, for shut-off and for preventing backflow.
You can read on to find out exactly what the water supply company was seeking to achieve, through the modernization of the Langenau plant. Or you can skip directly to the pneumatic solution from Festo.
For 100 years, the ground water from the Donauried could be used as drinking water, without needing any further treatment. Then the increasing pollution from industrial and domestic chemicals, from pesticides and from pharmaceutical residues, made it necessary to build a ground water filtration system. The special feature of this expansion was that a total of seven, two-story filter basins were constructed in an existing building. To enable this, a building that had been used for flocking and that was no longer needed, was demolished first. Resulting from this alone, there were very high requirements placed on the actuator technology. It had to be as space-saving as possible.
Pure gravity is used for the ground water filtration. The water flows from the top to the bottom through a multi-media sand filter and then through an active carbon filter. While the sand holds back larger pollutant particles, the active carbon removes even the smallest contaminants.
In comparison, the cleaning of the compressed air filter is not so easy, but it is essential. The retained particles and the suspended matter block up the compressed air filter and impede the water flow. Once the filter resistance has reached a threshold of 3.5 mWS, the affected compressed air filter has to be rinsed out. To do this, the coordinated opening and closing of ten butterfly valves in the piping has to be carried out.
For this purpose, the water supply company went on the search for an automation solution that would handle the water flow control and that would operate in very limited space. It had to be reliable and safe and it had to include everything: The actuators and the corresponding process valves for control, for shut-off and for preventing backflow.
Up to this point, the water supply company had relied almost exclusively on butterfly valves with spindle adjustment. The spindles were operated by a handwheel or by an electric motor. But there was no space for these in the Langenau plant any more. Alongside the complex pipework, 70 automated process valves had to be installed in the space.
The solution came in the shape of pneumatic actuators from Festo. The DAPS quarter turn actuators are supplied from a central compressed air station and controlled using valve manifolds. This makes the actuator spindles and helical gear units on the process valves surplus to requirements. With this solution, the actuator is mounted directly onto the valve disc shaft.
We are proud that the water supply company, based in Baden-Württemberg, modernized its water technology with Festo. The example proves how convincing the advantages of pneumatic automation are.
During the tendering phase, we were frequently on site and were able to stand our ground against the electrical solution with the pneumatics concept, both in a technical comparison and a cost comparison. And at the end of the day, the result was that the water supply company made the switch from the previously deployed electric actuators to a complete pneumatics system.
A plus point for Festo was the thorough consulting: Our experts helped with the calculation of the compressed air consumption and the optimum layout of the compressed air network. If required, we can also provide support during the tendering phase.
The bottom line is that automation with Festo is as simple and fault-free as pneumatics itself. With us, plant builders always get everything from a single source, with a single part number. This makes the order handling process simple and accelerates the implementation of the project.