Roughly 40 percent of the world’s population faces water shortages today. Experts expect that number to hit four billion by 2050. Many countries have turned to desalination, treating brackish or seawater to meet their water needs. But can we really call desalination a sustainable solution?

Seawater desalination isn’t just sustainable, it’s a real answer to our growing need for water – for homes, businesses, and industry. Desalination pulls salt out of brackish water, making it safe to drink, use for irrigation, and in manufacturing.

In the last ten years, production costs have halved. This happened thanks to the water treatment industry and companies that build membranes and equipment like turbines, pumps, and pressure exchangers. Desalination uses reverse osmosis, which is the most effective way to make seawater drinkable.

Reverse osmosis is a process that uses membranes to remove 99.9% of salts from water. To make sure desalination stays sustainable, we analyze the raw water quality, check environmental impacts, and pick the right technology. It works in all sorts of situations, like if you live on a coast or island and need to treat seawater. Desalination can even adjust automatically to seasonal changes.

The Engineering and Environmental Case for Sustainable Desalination

seawater-desalination-the-most-viable-solution-to-drought/”>Desalination sustainability has changed a lot in the last two decades. Seawater reverse osmosis (SWRO) now handles over 65 percent of global desalination. It’s largely replaced older thermal distillation methods, which used 10 to 15 kWh per cubic meter of freshwater. Modern SWRO plants, with their isobaric energy recovery devices, use just 2.5 to 3.5 kWh per cubic meter. That’s close to the theoretical minimum of about 1.0 kWh per cubic meter.

Key Technical Advances Driving Cost Reduction

For big utility projects, solar-powered SWRO plants in the Middle East and Australia now produce drinking water for 50 to 80 cents per cubic meter. That’s competitive with traditional freshwater treatment in places where water is scarce. Pressure exchanger energy recovery devices can recover up to 98 percent of the hydraulic energy from the high-pressure concentrate stream. This cuts net energy use by 30 to 40 percent compared to systems from the 1990s. High-permeability TFC membranes let more water through at lower operating pressures, reducing both energy use and the amount of membrane needed by up to 40 percent. Subsurface intake systems, including beach wells and horizontal directional drilling intakes, naturally pre-filter the water. This cuts down on chemical pre-treatment costs and avoids harming marine life, which can be an issue with open ocean intakes.

Brine Management and Environmental Compliance

The main environmental worry with desalination is how to get rid of the concentrate, or brine. A typical SWRO plant operating at 45 percent recovery sends back concentrate that’s about 1.8 times saltier than the incoming water. The best way to discharge this uses multi-port diffuser systems. These quickly dilute the concentrate through turbulent mixing, which keeps salinity low in the seafloor area. For inland brackish water desalination, where you can’t discharge into the ocean, Zero Liquid Discharge evaporation and crystallization systems recover salts as commercial by-products. This means true zero liquid discharge and complete water recovery.

AMPAC USA builds commercial and municipal RO systems for both brackish water under 10,000 ppm TDS and seawater uses. We ensure full compliance with EPA and state-level rules for concentrate disposal. The UN SDG 6 framework specifically says desalination is a good strategy for water-stressed nations. With over 21,000 plants running globally, producing 100 million cubic meters per day, desalination is moving from an emergency fix to a standard part of water infrastructure.