At the end of the 70's, the Madeira Archipelago pioneered a system that would respond to the needs of the region for the next 40 years. Inaugurated in 1980, the Porto Santo Desalination Plant was an investment made by the Regional Government of Madeira due to the water scarcity on Porto Santo – which worsened when the population increased and the first tourists began to arrive on the island.

Located in Vila Baleira, the Porto Santo Desalination Plant was one of five industrial units of its kind in the world with Reverse Osmosis technology. Currently, all the water that reaches consumers and agriculture comes from there. Indeed, it is the only source of drinking water used for the public supply of this island.

In 2019, the plant had a production capacity of around 6,500 m³ per day, which is enough to meet the needs of 5,000 permanent inhabitants that reaches nearly 20,000 during summer months.

According to Águas da Madeira, “it was also the first one to use an energy recovery system with a Pelton turbine, which became the technological standard for about 20 years. This important change allowed the reduction of energy waste between 35 and 40 percent and contributed to rolling out this technology worldwide”.

State of the art system

Nuno Pereira, administrator of Madeira's Water and Waste Production, the company responsible for the desalination plant, told Público Newspaper that “for every 100 litres of salt water that enters the system, 45 litres of drinking water come out”.

For this purpose, there are some desalination techniques that can be used in this type of mechanism, but the one chosen by Madeira was reverse osmosis, which is a technology that removes most contaminants from water by pushing water under pressure through a semipermeable membrane.

According to Público, at that time, most desalination plants in the world used thermal methods to remove salt from the water, which required greater energy consumption and as Porto Santo did not have enough energy capacity for this, the solution was to use the pioneering process of reverse osmosis.

In fact, the Porto Santo Desalination Plant was one of the first seawater desalination plants using reverse osmosis built in the world, and the first in Europe. Currently, the entire process has a total consumption of 3.5 kW/m³.

In addition, “the water that is rejected by the desalination process (which accounts for about 55 percent to 60 percent) is returned to the sea with about twice the concentration of mineral salts in the water.”

Good water quality

Despite the source of the water, its quality is not less than five stars, according to the company. “The water is of excellent quality”, they ensure.

Before the construction of this desalination plant, Porto Santo suffered from severe water scarcities, as natural water was not enough to meet the population's needs in terms of quantity and quality. The low levels of water from natural sources result from the characteristics of the island, where rainfall is 75 percent lower than on Madeira Island.

Although back then it was urgent to do something about it, now the water produced in this plant is more than enough to meet all needs. Without that, they admit that it would be impossible to grow economically and attract tourists, such as Porto Santo has done in recent years.