Silica
Source of Silica
Silica (SiO
2) is an oxide of silicon, and is present in almost all minerals: It is found in surface and well water in the range of 1 - 100 mg/i. Silica is considered to be colloidal in nature because of the way it reacts with adsorbents. A colloid is a gelatinous substance made up of non-diffusible particles that remain suspended in a fluid medium. Silica is objectionable in cooling tower makeup and boiler feedwater. Silica evaporates in a boiler at high temperatures and then redeposits on the turbine blades. These deposits must be periodically removed or damage to the turbine will occur. Silica is not listed in the Primary or the Secondary Drinking Water Standards issued by the US EPA.
Treatment of Silica
The anion exchange portion of the demineralization process can remove Silica. Reverse osmosis will reject 85 - 90% of the silica content in the water.