Patent ID: 7897049

Claim:
A method for purifying water, the method, comprising: passing contaminant-containing water through a reducing zone having a reducing agent present in an amount of less than about 10 wt % of the reducing zone at a pH of at least about 5, wherein the reducing agent comprises an iron-containing media, wherein the contaminant-containing water comprises at least one of cyanide, arsenic, chromium and selenium; reducing the oxidation-reduction potential of the contaminant-containing water in the reducing zone to not greater than about 0 mV, and restricting Fe 3+ and iron hydroxide production; flowing the contaminant-containing water from the reducing zone to a clean-up zone, the clean-up zone comprising at least 50 wt % zero valent iron; and removing contaminants from the contaminant-containing water, wherein the removing step comprises: corroding zero valent iron into Fe 2+ using the contaminant-containing water; forming precipitates from the Fe 2+ and contaminants of the contaminant-containing water; and removing precipitates from the water.