Seawater Desalination (RO)

Reverse osmosis pushes saline water at high pressure through a semi-permeable membrane that lets water molecules pass while rejecting dissolved salts. Seawater salinity is high (above 32,000 ppm along the Libyan coast), which calls for higher operating pressure, dedicated membranes, corrosion-resistant materials and a precise chemical protection program.

How a Seawater Desalination Plant Works

The process starts at the intake, followed by pretreatment to remove suspended solids and organic matter through sand filters, carbon filters and fine cartridge filtration. Antiscalant chemicals are then dosed, and the high-pressure pump drives the water into the membrane pressure vessels, where product water is separated from the concentrate. The line ends with pH adjustment, disinfection and storage in tanks.

Key Components

High-pressure pumps, seawater pressure vessels and membranes, pretreatment filters, a chemical dosing system, an electrical control panel, pressure, salinity and flow instruments, and product-water storage tanks. We use components from brands such as Pentair, Grundfos and Toray to ensure spare parts are readily available.

What Actually Drives the Cost

Three factors: raw-water salinity, required production capacity, and daily operating hours. Then comes operating cost, driven by power, membrane life and chemicals. A good design reduces the power used per cubic meter and extends membrane life — and that is the real difference between two proposals that may look similar in upfront price.

Protecting the Membranes

Membranes are the most expensive component in the plant, and protecting them is fundamentally a chemical matter. We use ALS 750, our antiscalant dedicated to seawater, to prevent salts from depositing on the membrane surface, and ALS 780 membrane cleaner in periodic cleaning cycles, while monitoring differential pressure and recovery to detect fouling early.

Seawater Desalination Projects We Have Delivered

A 30 m³/hour system on the Libyan coast for construction works and concrete mixing, and a 75 m³/day plant in Al-Maya for agricultural use.