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US 7,897,049 B2Granted
Methods for treating water using iron
AssigneeAlcoa Inc.
InventorsRajat S. Ghosh, Dennis Fulmer, Kevin Kitzman, John Smith
Life of this patent
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Abstract
Systems and associated methods for treating contaminant-containing wastewater are provided. The systems generally include a reducing zone for reducing the oxidation-reduction potential of the water and a clean-up zone comprising zero valent iron for removing at least a portion of the contaminant from the contaminant-containing water. The systems are operable to remove one or more contaminants from the contaminant-containing water and are operable for extended durations without clogging due to the formation of iron hydroxides.
Claims8
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 Fe3+ 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 Fe2+ using the contaminant-containing water;
- forming precipitates from the Fe2+ and contaminants of the contaminant-containing water;
- and removing precipitates from the water.
5 more elements
Dependencies are inferred from the claim text.