Colloidal

Colloidal iron is very small particles of oxidized iron suspended in the water. They are usually bound together with other substances. This iron looks more like a color than particles when held up in a clear glass, as they are so small. Treatment is usually one of three ways: Feed chlorine to oxidize the organic away from the iron, thus allowing agglomeration to occur, feeding polymers that attract the static charge on the particles, forming larger clumps of matter that is filterable or air injecton systems.