Culligan creates filtration system for the world’s deepest thermal pool, Y-40 –  The Deep Joy

BOLOGNA, ITALY, 3 August, 2013 – Culligan, a leading global innovator of advanced water treatment solutions for more than 80 years, has developed a custom filtration system to treat the thermal waters of Y-40 The Deep Joy, the deepest thermal pool in the world.

Located at the 4-star Hotel Terme Millepini in Montegrotto Terme (Padua), Italy, the massive 21 x 18 meters pool will have a maximum depth of 40 meters and will feature various intermediate depths as well as four caves for technical underwater diving. It will be filled with 4300 cubic meters of thermal water maintained at a constant temperature of 32-34°C, allowing users the option of diving and swimming without a wetsuit. Its expansive size and multi-level configuration enable the pool to support a variety of activities, such as scuba diving training for beginners, photo sessions for photographers and film producers, and professional diving for experts. Y-40 The Deep Joy is scheduled to open in early 2014.

The latest collaboration between Culligan and the Boaretto Group, the water treatment system for Y-40 The Deep Joy required painstaking work in order to address the many water treatment challenges imposed by the pool’s water chemistry, temperature, depth and configuration.

The source of the famous thermal waters of Montegrotto Terme is the uncontaminated basins of the Lessini mountains, located at the foothills of the Alps, over 80km away.  The long journey through the calcareous rock at a depth of 2000-3000 meters can take over 25 years. During this time, the water is held at high pressures and temperatures as it passes through the underground calcareous rock found in this region. When it finally emerges at a temperature of 87oC at Montegrotto Terme, the water is enriched with mineral salts, famous for their antioxidant, anti-inflammatory and antiseptic properties.

To resist the characteristics of this type of reactive water, the entire water filtration system – pumps, filters and accessories – is made completely of stainless steel (AISI 316).  Even the electrodes of the control and dosing units of chemicals are custom-made, and the filters have been coated internally with materials specifically designed to withstand the high temperatures and aggressive constituents of the thermal water.

Because of the pool depth and resulting pressure, the filters are also built to withstand a higher operating pressure than the more traditional 2.5 bar normally used. The closure system of pre-filters has also been modified to ensure a completely watertight seal under this amount of pressure.

The design engineering also addresses several other factors:

  • Because of the shape of the pool as well as its multiple zones and depths, the hydraulic circuit is specially configured to enable the appropriate hourly flow rates necessary for each different zone. The circuit and distribution of water from the accessories have been designed for low speeds of outlet water so as not to impede the ascent or descent of the divers.
  • The arrangement of the pipes inside the tank was developed after thorough study to determine the optimal dimensioning of reinforced concrete structures needed to protect the pipes.
  • An overflow channel perimeter enables recovery of the water without creating concentrated streams. The system features custom design and sizing of ducts and pipes that can accommodate the high flow rate due to the large volume of water.
  • The filtration system is also designed to enhance the ease of cleaning and maintenance. Culligan devised a system suitable for the cleaning of the bottom to -40 mt, in addition to the vacuum positioned about 2 meters from the bottom, designing an inlet system capable of sending the dirt into a suction grille mounted in the center of the “well” also situated at -40 meters. This additional cleaning system is configured to work when divers are not in the pool, and ensure the highest aesthetic quality of each pool area.
  • Moreover, a fifth automatic valve was added to make the filter cleaning system more efficient and help eliminate possible encrustations that could form inside. This solution allows better management of the washing and backwashing cycles. In addition, the entire system has been optimized by utilizing a dosing solution with hypochlorite upstream of the filters themselves.

“We have been working with Culligan for 35 years. Our three hotels – Hotel Terme Millepini in Montegrotto Terme, Best Western Premier Hotel Galileo in Padova, and Grand Hotel Terme Sardegna in Fordongianus – use their filtration systems. We feel the Culligan team is part of our company, and that we can guarantee the best water quality by working with them,” says Emanuele Boaretto, Owner of the Millepini Group.

“Y-40 the Deep Joy is a particular joy to be a part of, as it allows the Culligan team to leverage our extensive experience and leading-edge technologies to create the ideal solution for this new, world-class venue for divers,” says Laurence Bower, Senior Vice President EMEA, Culligan.

About Culligan International Company

For more than 80 years, Culligan has delivered innovative water treatment solutions to a broad range of markets and industries. It offers technologically advanced, state-of-the-art water treatment products and services covering all residential, business, commercial, swimming pool and industrial applications. Culligan’s network of franchise dealers is the largest in the world, with over 800 dealers in 90 countries. From design and conception through to installation, commissioning and after-sales service, Culligan is the global benchmark for water treatment solutions. For more information visit