{"id":113588,"date":"2025-09-04T09:02:09","date_gmt":"2025-09-04T09:02:09","guid":{"rendered":"https:\/\/www.newsbeep.com\/uk\/113588\/"},"modified":"2025-09-04T09:02:09","modified_gmt":"2025-09-04T09:02:09","slug":"desalination-doesnt-have-to-be-bad-for-the-environment-dw-09-03-2025","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/uk\/113588\/","title":{"rendered":"Desalination doesn’t have to be bad for the environment \u2013 DW \u2013 09\/03\/2025"},"content":{"rendered":"

For millennia, humans have sought to make\u00a0seawater<\/a> drinkable. Ancient mariners tried distillation by boiling the oceans in which they sailed, and in more\u00a0recent times, engineers have experimented with filters and chemicals<\/a> .\u00a0<\/p>\n

As the climate warms<\/a>, populations surge and droughts intensify<\/a>, there is a growing need to make the sea drinkable.\u00a0Desalination\u00a0technology is spreading fastest in the Middle East, North Africa and parts of Asia, where there is plenty of ocean\u00a0but dwindling supplies of fresh water.<\/a><\/p>\n

In 2023, there were an estimated 16,000 plants in operation globally, capable of making\u00a056 billion liters of desalinated water a day \u2014 around 7 liters for every person on the planet.\u00a0<\/p>\n

But creating drinking water from the sea is not without environmental impacts. These depend on how plants process seawater, whether they run on fossil fuels or renewable energy and where they are built.\u00a0<\/p>\n

\"DesalinationFor countries on the coast, desalination could be a solution to water scarcity Image: European Science Communication Institute (ESCI)<\/p>\n

Desalination’s salty problem<\/p>\n

The major obstacle to\u00a0using the sea to meet human water needs\u00a0\u2014\u00a0which the UN puts at between 50 and 100 liters per person per day \u2014 is that it contains too much salt to drink, and actually causes dehydration.\u00a0<\/p>\n

Reverse osmosis, today’s dominant desalination method, uses high-pressure membranes to filter out the salt, leaving behind drinkable water. But every liter produced this way generates\u00a0an almost equal volume of brine.<\/p>\n

This highly salty byproduct is often laced with chemicals like chlorine as well as antiscalants used to prevent salt buildup on equipment.\u00a0<\/p>\n

The easiest and cheapest way to get rid of this brine is to send it back into the sea. But once discharged, it tends to sink, forming dense layers on\u00a0the ocean floor. These layers deplete oxygen and\u00a0threaten marine ecosystems,<\/a>\u00a0particularly creatures like mollusks, sponges and seagrasses that provide food and shelter for other species.<\/p>\n

Brine also often contains heavy metals from corroding pipes and has been found to harm fish and broader\u00a0marine ecosystem health.\u00a0\u00a0<\/p>\n

But if dispersed properly, brine\u00a0isn’t necessarily harmful, according to Sergio Salinas Rodriguez, an associate professor at IHE Delft Institute for Water Education in the Netherlands.<\/p>\n

“Desalination plants add salt-based chemicals like iron chloride or aluminum sulfate to remove dirt, and antiscalants to prevent salt buildup,” he told DW. “But their volume is minuscule compared to the vastness of the ocean.”<\/p>\n

Can desalination solve the global water crisis? <\/p>\n

To view this video please enable JavaScript, and consider upgrading to a web browser that supports HTML5 video<\/a><\/p>\n

Are there ways to lessen the impact of brine?<\/p>\n

One way to soften the impact of discharged brine\u00a0is to dilute\u00a0it, as happens at the massive Carlsbad Desalination Plant in drought-prone California. The facility\u00a0produces 50 million gallons (189.27 million liters) of water a day for the San Diego region.<\/p>\n

Until the end of 2018, Carlsbad mixed the salty substance with cooling water from a neighboring power station before releasing it into the Pacific Ocean. Since the power plant shuttered, the desalination facility has instead been drawing\u00a0extra seawater to thin the brine. It uses what it describes as “fish-friendly” pumps to minimize injury to marine creatures.\u00a0<\/p>\n

Once discharged, ocean currents, wave action and the unique geography of the Agua Hedionda Lagoon, where Carlsbad is located, help disperse the salty plume.<\/p>\n

Four years of monitoring between 2019 and 2023 found waters off Carlsbad’s coast “remain healthy and\u00a0minimally impacted,” according to a study commissioned by the company that runs the plant.\u00a0<\/p>\n

Yet\u00a02019 research<\/a> by scientists at the University of California Santa Cruz found that salinity in brine discharge zones and further ashore sometimes exceeded permitted levels. They\u00a0said\u00a0stronger dilution could\u00a0help.<\/p>\n

But such strategies can’t be replicated everywhere. The Persian Gulf, for instance, is shallow, already very salty, and doesn’t have the same natural currents to disperse brine. Which is\u00a0why knowledge of the local seascape is important when building a desalination plant.<\/p>\n

“That needs to be a study of the currents, natural flow, and potential impact,” said Rodriguez.\u00a0<\/p>\n

Mining brine for valuable minerals\u00a0<\/p>\n

Others are looking to brine not as waste, but as a resource.\u00a0<\/p>\n

In Tenerife, Spain, an EU-funded project called Sea4Value is mining desalination brine for critical raw materials. The researchers aim to extract 10 minerals, including lithium and magnesium,<\/a> vital for batteries and manufacturing. At the same time, they also want to produce more drinking water and less brine waste.\u00a0<\/p>\n

“Our idea was to go from the 50% brine that’s usually produced to reduce it to around 20%,” said Sandra Casas Garriga, a researcher involved in the project. “So, from one cubic meter of seawater, we could obtain 800 liters of freshwater and 200 liters of brine.”<\/p>\n

Early trials carried out in a mobile lab unit successfully tested different techniques for recovering critical minerals from the byproduct. “We try to be as green as possible by reducing the impact of the process of recovery,” said Garriga, in reference to the\u00a0fresh water and critical minerals drawn from the sea.<\/p>\n

Other companies, including in the US, are also running pilot projects to test ways of extracting minerals like magnesium from brine.\u00a0<\/p>\n

\"CalciumThe project Sea4Value is mining desalination brine for critical raw materialsImage: European Science Communication Institute (ESCI)<\/p>\n

Choosing the right location for desalination\u00a0<\/p>\n

Some of desalination’s other environmental impacts could be lessened by choosing the right plant location, say experts.\u00a0<\/p>\n

Kotb Mohamed, a postdoctoral fellow at the Interdisciplinary Research Center for Sustainable Energy Systems in Saudi Arabia, created a tool that identifies the best locations for seawater reverse osmosis plants powered by solar and wind.<\/p>\n

The model was first tested on Egypt’s Red Sea Coast and can be applied to arid coastal regions in North Africa, the Gulf, South Asia and parts of Europe, he said.\u00a0Most desalination plants currently\u00a0run on the\u00a0fossil fuels that emit planet-heating greenhouse gases.<\/p>\n

“There are three major environmental benefits of the model, which are reduced fossil fuel dependence<\/a> and greenhouse gas reductions<\/a>, minimized land degradation or erosion and efficient use of local resources.”\u00a0<\/p>\n

He added that plants built near population centers with existing infrastructure could avoid long water pipelines, thereby saving energy and land, though this may not be feasible in less developed areas.<\/p>\n

“When done properly, and all cares are taken,\u00a0desalination<\/a>\u00a0is environmentally defensible,” said Rodriguez from the Delft Institute. “But it needs to take the proper measures […] from the design of the plant, finding a location in the sea that is proper for abstracting the water and also for discharging.”<\/p>\n

Edited by: Jennifer Collins<\/p>\n","protected":false},"excerpt":{"rendered":"For millennia, humans have sought to make\u00a0seawater drinkable. Ancient mariners tried distillation by boiling the oceans in which…\n","protected":false},"author":2,"featured_media":113589,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[22],"tags":[1397,90,56,54,55],"class_list":["post-113588","post","type-post","status-publish","format-standard","has-post-thumbnail","category-environment","tag-environment","tag-science","tag-uk","tag-united-kingdom","tag-unitedkingdom"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/posts\/113588","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/comments?post=113588"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/posts\/113588\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/media\/113589"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/media?parent=113588"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/categories?post=113588"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/tags?post=113588"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}