There are several treatment processes for desalination, including reverse osmosis, thermal distillation, and electrodialysis. Reverse osmosis (RO) is currently the most widely used desalination technology, accounting for over 60% of global desalination capacity. In RO, seawater is forced through a semipermeable membrane under high pressure, which separates the salt and other minerals from the water. Thermal distillation, which involves boiling seawater and condensing the vapor to produce freshwater, is typically used in large-scale desalination plants.

Pretreatment is a critical step in desalination to protect reverse osmosis (RO) membranes and ensure system reliability. Among the most commonly used methods are ultrafiltration (UF) and chemical coagulation. UF membranes provide effective and consistent removal of suspended solids, microorganisms, and colloidal particles, offering a compact and reliable alternative to traditional media filters. Chemical coagulation, often using agents like ferric chloride or alum, helps aggregate fine particles and organics, improving their removal in downstream filtration processes. These methods are frequently used in combination to reduce fouling potential, enhance membrane lifespan, and maintain stable operation in both seawater and brackish water desalination plants.