Manganese greensand is a type of glauconite that is coated with manganese oxide by means of special processing. Manganese greensand is a common filter media which removes hydrogen sulfide, iron and manganese.
The manufacturing process of manganese greensand begins with glauconite. The glauconite, or greensand, is cleaned and then filtered (sifted) so only the pieces of greensand of the proper size are kept. Once all the correctly sized pieces are collected they are coated with manganese oxide.
Manganese greensand is one of the most popular ways to filter water when hydrogen sulfide, iron or manganese are a concern. When filtering iron, the manganese greensand is used in a process called continuous regeneration. In this process, a solution is fed into the water supply that oxidizes the iron. The oxidized iron is then filtered out by the manganese greensand. A process called intermittent regeneration is used when using manganese greensand to filter manganese.
Greensand works because of its manganese dioxide coating. This coating reacts with mineral particles in water and traps them, drawing the water molecules down through the sand and into the soil. The substrate particles form a bond that allows water to seep in where it is held in place, saving it for the plants to use later.