The commonly used process in direct drinking water treatment systems is the reverse osmosis process, which employs ultraviolet radiation for disinfection to prevent secondary contamination of the water quality.

There are numerous industries that use pure water equipment in industrial applications, such as: boiler feed water, cooling tower make-up water, electroplating plants, electronics and battery manufacturing, metallurgy, chemical production, cement plants, coal-fired power plants, nuclear power plants, and the textile dyeing industry, among others. Depending on the specific production process, the quality requirements for process water vary. However, in general, the process water used in industry is mostly softened water, pure water, or even ultrapure water.

Reverse osmosis equipment, also known as high-filtration equipment, is the reverse process of natural osmosis. The driving force is pressure difference. This membrane separation technology works by applying pressure higher than the osmotic pressure to the solution to be separated, forcing the solvent (water) from the feed solution to permeate through the membrane to the other side. Substances such as ions, organic matter, bacteria, and viruses are retained on the feed side of the membrane and then discharged with the concentrated stream, thereby achieving separation and purification. Reverse osmosis (RO) equipment has a very high filtration precision. It can filter out almost all substances except water molecules, including microorganisms, bacteria, and metal ions. The purity of the produced water is extremely high, second only to distilled water. Its technical characteristics include no phase change, low energy consumption, compact structure, simple operation, easy maintenance, and no environmental pollution. Reverse osmosis processes are applied to different raw water sources and are classified into seawater desalination membranes, anti-fouling high-pressure membranes, and low-pressure membranes.