Radium Removal with GreensandPlus
There are several methods to remove radium from drinking water. It can be removed by ion exchange, adsorbed or precipitated and filtered. Radium will be removed in sodium cycle cation exchange (the water softening process). After the service run, the resin is regenerated with brine and the radium is regenerated off the resin and concentrated in the waste brine. Radium can also be removed in a co-precipitation process similar to removing arsenic. Whereas arsenic will combine with an iron floc, radium will combine with a manganese floc and can be filtered. If there is not enough manganese in the raw water to remove the radium, manganese can be added in the form of hydrous manganese oxide (HMO). If manganese is present, H&T recommends GreensandPlus as the media to remove the soluble manganese along with the radium. If manganese is not present, a dual media bed of sand and anthracite can be used instead. When the filter is backwashed, the radium attached to the manganese floc is backwashed from the filter. The backwash waste can be settled and the supernatant recovered, thereby reducing the amount of waste disposal by about 85%. Selection of the best process for your application depends on if manganese also needs to be removed, ease of disposing of waste containing radium, hardness of the water and need for softening.