The reverse osmosis (RO) membrane elements in LANXESS’s Lewabrane line of products are spirally wound, thin-film, composite membranes. They filter out undesirable substances from water, such as salts, pesticides, herbicides, viruses, bacteria and particulates. The product line includes elements for all the main RO applications, including desalinating seawater, brackish water and low-salinity water. Leading fields of application include the production and treatment of drinking water, also the treatment of process water, other industrial water, and wastewater. Among the most important applications for RO membranes are the treatment of process water for power plants and the generation of ultrapure water in the microelectronics sector. Another area of application for RO membranes is the production of drinking water from both brackish water and seawater. This method is used on a large scale in cities and municipalities and on a small scale in restaurants, hotels and on cruise ships. The membranes lower the salt and particle content of the water and are often combined with ion exchange resins to form a highly efficient and very powerful demineralisation system. Lewabrane membrane elements chemistry depends on a strongly crosslinked polyamide layer that displays high resistance to chemical cleansers, higher rejection of complex salt mixtures and a low surface charge, which reduces the tendency toward fouling.