Reverse osmosis units also have cartridge filters installed immediately ahead of the RO unit to remove suspended matter down to _____.

Reverse osmosis units also have cartridge filters installed immediately ahead of the RO unit to remove suspended matter down to _____.

• A. 1-3 mm
• B. 3-5 mm
• C. 10-15 mm
• D. 5-10 mm

Answer: (D)

Before the water reaches the RO membrane, a cartridge sediment filter acts as a prefilter to remove suspended solids that could clog or foul the membrane. The goal is to reduce particulates to a very fine size—around 5 to 10 microns—so the membrane stays clean and flow remains adequate. Coarser options would leave too many solids and increase fouling, while a finer micron rating provides effective protection with an acceptable pressure drop. That’s why the correct choice reflects a fine micron-range filtration.

Before the water reaches the RO membrane, a cartridge sediment filter acts as a prefilter to remove suspended solids that could clog or foul the membrane. The goal is to reduce particulates to a very fine size—around 5 to 10 microns—so the membrane stays clean and flow remains adequate. Coarser options would leave too many solids and increase fouling, while a finer micron rating provides effective protection with an acceptable pressure drop. That’s why the correct choice reflects a fine micron-range filtration.