A reverse osmosis (RO) filter system is a water purification process that uses a semipermeable membrane to remove a wide range of contaminants from water. The system works by applying pressure to force water molecules through the membrane while blocking larger particles, ions, and molecules. Here’s how the process works step by step:
- Prefiltration: Before the water enters the RO membrane, it typically goes through a prefiltration stage. This stage involves passing the water through one or more filters (like sediment and carbon filters) to remove larger particles, sediment, chlorine, and some organic compounds. This helps protect the RO membrane from damage and improves the efficiency of the overall process.
- Pressurization: The prefiltered water is then pressurized using a pump. Applying pressure is a crucial step because it helps overcome the natural osmotic pressure and forces water molecules through the semipermeable membrane.
- Semipermeable Membrane: The heart of the reverse osmosis system is the semipermeable membrane. This membrane has extremely small pores that allow water molecules to pass through while blocking the passage of larger molecules, ions, and contaminants. As the pressurized water is forced against the membrane, the water molecules are pushed through these tiny pores, leaving behind a concentrated solution of contaminants and impurities on one side of the membrane.
- Permeate and Concentrate Streams: The water that passes through the membrane is called the permeate. It’s the purified water that is collected and stored for use. The concentrated solution left behind on the other side of the membrane, containing the rejected contaminants, is called the concentrate or brine. A portion of this concentrate is typically flushed out of the system to prevent the buildup of impurities on the membrane surface.
- Product and Waste Water Separation: The permeate, which is the purified water, is collected and stored for use. Meanwhile, the concentrate or waste water is directed out of the system and either disposed of or recycled.
- Post-Treatment: In some RO systems, there may be additional post-treatment stages to improve the taste and quality of the purified water. This could involve passing the permeate through additional filters, such as activated carbon filters, to further remove any residual tastes, odors, or remaining impurities.
Reverse osmosis is highly effective at removing a wide range of contaminants, including minerals, salts, dissolved solids, bacteria, viruses, and many organic and inorganic compounds. It’s commonly used for purifying drinking water, as well as in various industrial and commercial applications where highly purified water is required.
