A Cuban Town Improves Water Quality Through Desalination

Two people collect drinking water in plastic containers at the intake of the pumping station of the desalination plant located in Las Mangas, Granma province, Cuba. Credit: Jorge Luis Baños / IPS

By Dariel Pradas
BAYAMO, Cuba, Sep 9 2024 (IPS)

Overnight, hundreds of people in the rural community of Las Mangas, located in Granma province in eastern Cuba, realised something they had already suspected: that the water they had been drinking for decades was not exactly crystal clear, but rather “salty”, as they say.

It was certainly a positive change, thanks to a desalination plant that started operating in August, five years after construction began in 2019, with a US$ 61,000 investment by the Granma Provincial Delegation of Hydraulic Resources.

“We did a test and the water coming from the plant freezes clear, while the water from the street freezes white, because of impurities. Now, with the plant, the people are happy,” community representative Rodolfo Echavarría, 55, told IPS.

Las Mangas is part of the municipality of Bayamo, the provincial capital, some 740 kilometres east of Havana. It has water networks that carry water from a well to the connections in the houses.

However, the water source contains a salinity rate exceeding one gram of soluble salts per litre of water, the limit permitted for human consumption by the country’s health authorities.“The desalination plant is a great benefit, a marvel. If something as necessary as water is not good, imagine the damage it causes to health": Óscar Fajardo.

“The desalination plant was built at the outlet of this brackish well, serving as an easy access point (where people can fetch the processed liquid with containers),” explained Yasser Vázquez, deputy sub-delegate of the Water Resources Delegation in Granma, in an interview with IPS in Bayamo.

The new facility, the third of its kind in the province, processes 2,000 litres of water a day and, according to the planners’ estimates, benefits 1,097 inhabitants. Echavarría believes that number rises to almost 2,000 people, since the villages of El Chungo, La Bayamesa and Santa María, all more than three kilometres from Las Mangas, also benefit.

The plant’s purification system uses the reverse osmosis method, one of the most widespread globally. There are others such as distillation, freezing, hydrate formation, flash evaporation or electrodialysis.

Reverse osmosis involves applying pressure to brackish water and making it flow through a semi-permeable membrane whose role is to allow the solvent (water) to pass through, but not the solute (dissolved salts).

In essence, the water in a pressurised saline solution is separated from the dissolved salts as it passes through the membrane and then goes through further rounds of filtration and chemical injection until it reaches the required standards of potability.

A local resident, Yoel González, 52, was trained to operate the plant and is in charge of its maintenance.

“You have to know how it works, because there are things that can go wrong, as has happened. I have lived all my life in Las Mangas and the best thing that has happened here is this (the installation of the desalination plant). Water has always been difficult. We used to drink that brackish water, and you could taste the acid and salt in it,” he told IPS.

A change of scenery, or rather, of waters

In this village eight kilometres from the city of Bayamo, between 6:00 am and 6:00 pm, when the desalination plant opens, people gather at the site’s only existing tap and fill various-sized containers.

The water coming out of the tap in every home or facility in Las Mangas, the brackish water that barely comes out of the well chlorinated, is only used for cleaning, dishes, laundry and sometimes cooking. In this agricultural and livestock farming village, some farmers also use it to quench their animals’ thirst.

“When the plant was set up, people said at the beginning: ‘I drink it from the street, I’ve been drinking it all my life and I haven’t died’. Cubans are like that. But when they tried the new one, everything changed,” argued Echavarría, the community leader.

Nancy Gómez, 72, was born there and is one of the few people who resists the change.

“The neighbours are surprised because I don’t look for fresh water, but I’m used to it and it has never caused me any health problems. My children grew up drinking that (brackish) water. But my granddaughter does bring it from the plant for the children and I drink it from time to time. You can taste the difference,” she told IPS.

Oscar Fajardo, 50, has always avoided drinking water from the well since he moved to Las Mangas four years ago from Guasimilla, eight kilometres away.

In his home town, the water tasted fresh and “sweet”, so he never got used to the new saltiness. Even after moving away, Fajardo still fetched it in Guasimilla on his electric motorbike whenever he visited his mother.

“I would look for water there or in other places. Sometimes I had to drink the bad one, but after seeing the sediment that accumulated in the knobs and pots, I tried to avoid it. People here have adapted to drinking brackish water, but a few found alternative ways,” he told IPS.

While it was common to boil and drink the tap water, some people who knew better or had more money would go to Bayamo or El Chungo to fill their own household containers, or buy the liquid from owners of horse-drawn carts, who would sell 200 litres for the equivalent of US$ 0.40.

“The desalination plant is a great benefit, a marvel. If something as necessary as water is not good, imagine the damage it causes to health,” said Fajardo.

Dangers of salinated water

The risks of consuming water with excess salt are varied: upset stomach, dehydration, high blood pressure, fluid retention in the body or kidney damage.

After all, salt contains, in addition to the chloride electrolyte, sodium, a mineral harmful to the human body in many ways when ingested in large quantities.

The World Health Organisation (WHO) recommends an intake of no more than five grams of salt per day, equivalent to two grams (2000 mg) of sodium.

González, the operator of the Las Mangas desalination plant, said the community has several cases of kidney stones (also called nephrolithiasis or urolithiasis), which are hard deposits made of minerals and salts that form inside the kidneys and can affect any part of the urinary tract.

They may have arisen from prolonged consumption of brackish water, as several villagers interviewed by IPS suspect.

“One of my children complains when he urinates because of the stones, and he gets renal colics all the time,” said Gómez, the resident who is reluctant to drink the water processed by the plant.

Marisol Hildago, 37, also a resident of Las Mangas and mother of two, used to drink tap water until something caused her to start looking for water from El Chungo.

“My father suffered from chronic renal insufficiency and that’s why I started to look for water there. Now we only drink water from the plant and my father has improved,” she told IPS.

Water issues in the province

Las Mangas is not the only community in Granma with water-related issues. There are others where the subsurface basins and water sources have high levels of salinity, which often receive drinking water from tanker trucks.

Granma, known as the ‘Key to the Cauto’ (river), where the longest watercourse in all the Antilles flows at 343 kilometres, also has a low-isometric relief and boggy areas, which makes it more vulnerable to seawater encroachment and saline intrusion into the water table, as happens in Las Mangas and other places.

Some scholars claim that the river’s flow has decreased in part due to climate change, deforestation and the construction of the Cauto del Paso reservoir, the third largest in the country and inaugurated in 1992.

With the lowering of the river level, seawater encroaches with greater force through the course itself, affecting the water basins of some lands at the mouth of the Cauto.

This province with 804,000 people – in a country with a population of 10 million – has had a stable water situation with its supply sources since the heavy rains of June 2023, which, in addition to filling reservoirs and restoring the water table, destroyed part of the infrastructure.

Granma generally suffers from droughts which, according to water authorities, affect up to 100,000 of its inhabitants.

When this happens, river flow decreases and saline intrusion from the sea increases, disabling numerous wells, especially the shallower, artisanal ones, which are a solution for residents in places that are difficult to access.

The other major problem lies in the accessibility of water networks and the availability of the service, as only 76% of the province’s population receives piped water in their homes and only 38.7% (some 310,000 people) receive water at home at least once every three days.

Other more affected areas, such as the coastal municipality of Manzanillo, can get water supplies for up to 20 days. In all, more than 66,000 residents are supplied by water tankers.

A further 15 desalination plants are planned for Granma, to be added to the dozens existing throughout the country. In the last decade, the Cuban government has promoted the construction of these hydraulic works, both in communities with salinised water sources and in industries and beach resorts.