Methods for reducing the concentration of one or more contaminants in water using zero-valent iron media. In the method, a mixed aluminum (III) and iron (II) salt solution is added to water containing one or more contaminants that is in contact with a zero-valent iron media that comprises (a) a reactive solid comprising zero-valent iron and one or more iron oxide minerals in contact therewith and (b) magnetite to provide an aqueous reaction medium. The aqueous reaction medium is contacted with the zero-valent iron media for a period of time sufficient to reduce the concentration of one or more of the contaminants.