Today, nearly 40 percent of the world population is suffering from water shortage issue, which is expected to reach to four billion by 2050. Many countries worldwide have opted desalination of brackish or seawater to meet their water needs. But can we view desalination as a sustainable solution?

Seawater desalination is not only sustainable but is also a solution to the increasing need of water for domestic, industrial and commercial use. Desalination is the process of extracting salt from brackish water to make it usable for drinking, irrigation and industry processes.

In the last decade, the production costs have decreased by a factor of two. It has become possible due to the efforts of water treatment industry and manufacturers of membranes and equipment such as turbines, pumps, and pressure exchangers. Desalination works on the reverse osmosis process, which is most efficient to make seawater drinkable.

Reverse osmosis is a membrane-based separation process that enables removal of 99.9% of the salts from water. To ensure sustainability of desalination process raw water quality is analyzed, environmental impacts are examined and appropriate line technology is defined. It is also suited with all the contexts, such as if you live in a coastal region or island where you need to treat seawater. Desalination process can also be automatically adjusted to the seasonal variations.

The Engineering and Environmental Case for Sustainable Desalination

Desalination sustainability has transformed dramatically over the past two decades. Seawater reverse osmosis (SWRO) now accounts for over 65 percent of global desalination capacity, largely displacing thermal distillation methods that consumed 10 to 15 kWh per cubic meter of freshwater produced. Modern SWRO plants equipped with isobaric energy recovery devices achieve specific energy consumption of 2.5 to 3.5 kWh per cubic meter, approaching the theoretical thermodynamic minimum of approximately 1.0 kWh per cubic meter.

Key Technical Advances Driving Cost Reduction

At utility scale, solar-powered SWRO installations in the Middle East and Australia now produce drinking water at 50 to 80 cents per cubic meter, competitive with conventional freshwater treatment in water-scarce regions. Pressure exchanger energy recovery devices recover up to 98 percent of hydraulic energy from the high-pressure concentrate stream, reducing net energy consumption by 30 to 40 percent compared to 1990s systems. High-permeability TFC membranes achieve higher water flux at lower operating pressures, reducing both energy use and required membrane surface area by up to 40 percent. Subsurface intake systems including beach wells and horizontal directional drilling intakes provide natural pre-filtration, reducing chemical pre-treatment costs and eliminating marine life impingement concerns that affect open ocean intakes.

Brine Management and Environmental Compliance

The primary environmental concern in desalination is concentrate or brine disposal. A typical SWRO plant operating at 45 percent recovery returns concentrate at approximately 1.8 times feedwater salinity. Best-practice discharge employs multi-port diffuser systems that rapidly dilute concentrate through turbulent mixing, minimizing benthic zone salinity impact. For inland brackish water desalination where ocean discharge is unavailable, Zero Liquid Discharge evaporation and crystallization systems recover salts as commercial by-products, achieving true zero liquid discharge and complete water recovery.

AMPAC USA designs commercial and municipal RO systems for both brackish water under 10,000 ppm TDS and seawater applications, with full compliance engineering for EPA and state-level concentrate disposal requirements. The UN SDG 6 framework explicitly recognizes desalination as a legitimate strategy for water-stressed nations, and with over 21,000 plants operational globally producing 100 million cubic meters per day, desalination is transitioning from emergency measure to mainstream water infrastructure.