It was found that RO membranes are capable of removing nearly all contaminants, including pharmaceuticals and hormone disruptors see “Another Inconvenient Truth”.The efficient removal of various contaminants can vary; homeowners should evaluate all options when considering using an RO for home treatment. Other treatment methods may be better for specific contaminants.
Basic components of an RO system should include a prefilter to remove fouling agents and chlorine; an RO module containing the membrane; an activated carbon postfilter to remove residual taste, odor and some compounds from the purified water; a storage tank; and various valves. Prefilters containing activated carbon are commonly used to protect RO chlorine-sensitive membranes. A particular major disadvantage of RO is the large amount of contaminated wastewater generated. This can be as much as 50 to 90 percent of the incoming water. This amount depends largely on the pressure difference across the membrane. The larger the pressure difference, the smaller the wastage rate. A small pump may be used to increase the pressure differential and decrease the wastewater stream.
