Determination of Radium Removal Efficiencies in Water Treatment Processes.

摘要

Numerous well-water supplies for public water systems contain naturally occurring radium-226. Methods for removing radium from drinking water are needed so that drinking water treatment plants may meet the limit set in the EPA drinking water regulations for radium in drinking water. Studies were performed by State agencies at 14cities in Iowa and Illinois to determine the radium removal efficiency of four water treatment processes. Populations served by the water treatment plants ranged from 235to 25,000. The radium-226concentration in the raw water was greater than 5pCi/liter at 13of the supplies and ranged from 3to 49pCi/liter. Radium removal efficiencies at plants using reverse osmosis and sodium ion-exchange processes were generally about 92%. A much wider range of removal efficiencies, 75% to 95%,was found at plants using the lime-soda ash softening process with the removal varying with process pH. Plants using iron removal processes only were found to have radium removals ranging from 11% to 53%.