Xylem provides water-recycling solution for Rome fountains

Xylem provides water-recycling solution for Rome fountains

With more than 2,000 fountains, Rome needs to be careful about how it uses its water. The city recently decided to install a water recycling and treatment system for three of its most famous fountains at Piazza Navona. A solution developed by Xylem and the utility company Acea will help conserve water and protect the fountains from corrosion.

Many of Rome’s fountains are still supplied with water from the city’s aqueduct system. Once the water – often a great deal of it – passes through the fountains, however, it enters the sewage system and arrives at wastewater treatment plants. Acea, the company responsible for managing all of Rome’s fountains, has recently been working to optimize the use of water resources since water treatment can be costly.

One of the areas that Acea has focused on is the Piazza Navona, a public square with three fountains, including the spectacular Fontana dei Quattro Fiumi. Standing in the middle of the square, the fountain was created in 1651 and depicts four river gods seated around an Egyptian obelisk. The gods represent four major rivers of the world: the Nile, the Danube, the Ganges and the Río de la Plata.

“What we wanted to achieve,” explains Guglielmo Ranalletta, Director of Acea, “was to recycle the water of the fountains by circulating it through a pump system.”

This would be a relatively simple operation for a common town fountain, but complications arise when working with artwork more than 360 years old that has to be carefully preserved.

A compact, underground utility room

The first problem to be addressed in this project was to create an underground utility room to store the pumps. This room had to be built without disturbing the fountains. Since excavation was kept to a minimum, the utility room could not be made watertight and there was little space to work with.

In the course of Acea’s preliminary meetings with Xylem, particular attention was focused on the risk of the utility room flooding during heavy rains. Acea has been working with Xylem’s Flygt pumps for more than 30 years. Eventually it was decided to install Flygt 3171 N-pumps under the Fontana dei Quattro Fiumi. These pumps are particularly compact, energy efficient, and submersible.

Flygt was chosen for its high level of reliability, says Acea manager Edoardo Fanti. “Since the entire recycling system has been designed to reduce energy consumption and water, we were looking for a highly efficient pump,” says Fanti. “This feature is relatively widespread among manufacturers, but it is more difficult to have real guarantees on reliability. Any non-routine intervention at Piazza Navona requires the involvement of multiple agencies, which is a situation we want to avoid.”

In order to further reduce energy consumption, the speed of the Flygt pumps can be programmed to slow down at night or be remotely managed to suit current needs.

Ensuring high-quality water

In consultation with various agencies, Acea found a suitable place in the basement of the nearby Museo di Roma to install the treatment system for the fountains’ water. Acea created the overall design of the system, with Xylem consulting about the best pump applications. The final solution included small vertical multistage pumps from Xylem for circulating water in the treatment tanks.

The water used for the fountains comes from Lake Bracciano, as it has for hundreds of years. Though the water itself would not damage the fountains, the salt in the water could damage the equipment. In addition, varying weather conditions, temperatures and air pollution change the quality of the recycled water over time, so it needs to be constantly monitored.

The installed treatment system collects water quality data at the fountains and transmits it automatically to specialized technicians at Acea’s headquarters. A series of portable instruments also continuously monitor more than 20 chemical and physical parameters of the water. The technicians are also able to identify the best time to completely replace the water, since this activity needs to be limited.

“The success of this project,” says Acea Director Guglielmo Ranalletta, “is the result of a fruitful cooperation with Xylem established over several decades.”

by Simon