Reverse Osmosis (RO) is a filtration process that utilizes semi-permeable spiral-wound membranes to remove dissolved solids, organic matter, pyrogens, submicron colloidal particles, color, nitrates, and bacteria from water. Under pressure, feed water passes through the membrane, allowing purified water, known as permeate water, to pass through its microscopic pores. Meanwhile, the concentrated impurities are separated and discharged as reject water, also called concentrate water.  
RO membranes are widely used in various small-scale systems, including household water purification, hospital and laboratory cleaning, and other specialized water treatment applications. They provide high flux performance comparable to conventional low-pass filtration while effectively removing salts and contaminants.