Desalination Meets Sustainability

The Growing Importance of Desalination in Water Supply

Water scarcity is a pressing global issue, and as populations grow and climate change intensifies, the need for alternative water sources becomes increasingly urgent. One of the most promising solutions is desalination — the process of converting seawater into potable water. While this technology has been around for centuries, modern advancements have made it more efficient and widespread than ever before.

Desalination has evolved from ancient methods like boiling seawater to more sophisticated techniques such as reverse osmosis, which uses high-pressure membranes to filter out salt. Today, there are over 16,000 desalination plants operating worldwide, producing an estimated 56 billion liters of fresh water daily. This equates to about 7 liters per person on the planet, highlighting the scale of this industry.

However, the environmental impact of desalination cannot be ignored. The process generates a significant amount of brine — a highly concentrated saltwater byproduct that can harm marine ecosystems if not managed properly. Understanding how to mitigate these effects is crucial for sustainable water production.

The Environmental Challenges of Brine Discharge

One of the main challenges with desalination is the disposal of brine. Reverse osmosis, the most common method, produces nearly equal volumes of brine and fresh water. This brine often contains chemicals used in the filtration process, such as chlorine and antiscalants, as well as heavy metals from corroded pipes. When released into the ocean, it can create dense layers that deplete oxygen and threaten marine life.

Despite these risks, some experts argue that brine doesn’t have to be harmful if properly diluted. For example, the Carlsbad Desalination Plant in California uses a combination of seawater and cooling water to dilute its brine before discharge. Natural ocean currents and local geography also help disperse the salty plume, minimizing its impact. However, this approach may not be feasible everywhere, especially in regions like the Persian Gulf, where shallow waters and limited currents make brine management more challenging.

Innovations in Brine Management

Rather than viewing brine as waste, some researchers are exploring ways to extract valuable resources from it. In Tenerife, Spain, the EU-funded Sea4Value project is mining desalination brine for critical minerals such as lithium and magnesium, which are essential for batteries and manufacturing. By reducing the volume of brine produced, this initiative aims to minimize environmental harm while maximizing resource recovery.

Similarly, companies in the U.S. are testing methods to extract magnesium and other minerals from brine. These innovations could transform desalination from a costly and environmentally damaging process into a more sustainable and economically viable solution.

Choosing the Right Location for Desalination Plants

Location plays a key role in minimizing the environmental impact of desalination. Experts suggest that careful planning can reduce energy consumption, land degradation, and greenhouse gas emissions. For instance, a tool developed by Kotb Mohamed at Saudi Arabia’s Interdisciplinary Research Center for Sustainable Energy Systems identifies optimal locations for solar- and wind-powered desalination plants.

This model, tested along Egypt’s Red Sea Coast, could be applied to arid coastal regions across North Africa, the Gulf, South Asia, and parts of Europe. By using renewable energy and building near population centers, desalination plants can avoid long water pipelines and reduce their carbon footprint.

The Future of Desalination

While desalination is not without its challenges, many believe it can be an environmentally responsible solution when implemented correctly. According to Sergio Salinas Rodriguez of IHE Delft Institute for Water Education, proper design, location selection, and brine management are essential for sustainable operations.

As demand for freshwater continues to rise, the future of desalination will depend on innovation, careful planning, and a commitment to minimizing environmental harm. With the right strategies in place, this technology could play a vital role in securing water supplies for millions of people around the world.