Process automation for ambitious water treatment project at Nuremberg Zoo.

A water treatment plant with state-of-the-art process automation technology is improving the living conditions of dolphins.

The new dolphin lagoon at Nuremberg Zoo is setting new standards for the care of sea mammals. Large outdoor pools provide more space and variety than any previous European dolphinarium. The water treatment plant with state-of-the-art process automation technology is critical to the wellbeing and living conditions of the animals.

Anyone who owns an aquarium knows how difficult it is to maintain water quality at a consistently high level. The principle “the larger the tank, the more stable the water values” depends on the number and size of its inhabitants. When they are dolphins, like at Nuremberg Zoo, the water treatment requirements are particularly challenging.

Nuremberg dolphin lagoon: State-of-the-art filter plants with Festo automation technology ensure maximum water quality. (Photo: Tiergarten Nürnberg) 

Cleaner than a swimming pool!
“The water in the Nuremberg Zoo dolphin lagoon is cleaner than that of any swimming pool,” says Klaus Held from engineering firm Sixt, Heiß & Partner, specialists in complex water treatment installations. “In terms of the durability and corrosion resistance of process valves and actuators, saltwater poses much greater challenges than the chlorinated fresh water used in swimming pools.” 

Nuremberg Zoo has its very own water treatment plant, where 2,000 cubic metres of fresh water are treated every hour. This enormous volume of water is essential for the health of its marine mammals. The plant also has to process out vegetation and animal excrement. To ensure that even in cold weather, temperatures in the outdoor pools never fall below 17 °C, the water is pre-heated to 30 °C. If outdoor air temperatures drop below –5 °C, an air dome prevents the two pools from becoming too cold.

Pneumatics reduces noise stress
The pneumatics used in the new system significantly reduces noise pollution for the dolphins. “The electric drives that we used before transmitted noise through the piping to the pools. This meant constant noise stress for the dolphins, which has been virtually eliminated with the pneumatic actuators from Festo,” says Held.

The lagoon water runs through a total of six closed multi-layer filters, which are flushed out at regular intervals. To do this, the inlet and outlet are closed and the cleaning air and rinsing water are opened. The contamination exits the system via a sludge discharge and the water filters then work at full capacity again. Quarter turn actuators [DAPS] from Festo operate the main butterfly valves. They are controlled using a total of seven control cabinets supplied completely ready-to-install – equipped with valve terminals type CPX-VTSA providing the pilot operation signals – at management level.

Everything from a single source
The decision to use Festo as the process automation supplier was made during the planning phase on the basis of Festo's extensive product portfolio.

“Plant manufacturer WTA Plauen quickly came to the conclusion that we could supply all their process products,” explains Festo’s Tobias Brucker, responsible for the water and wastewater industry in Germany, and Jürgen Zeiträg from the project engineering process automation team at Festo.