Process for removal of selenium from water by dithionite ions
AssigneeEcolab USA Inc.
InventorsTarun Kumar Bera, Jitendra T. Shah, Vaideeswaran Sivaswamy
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Abstract
A method for efficiently removal of oxidised selenium from liquid, such as FGD wastewater. The method involves adding a non-iron-based reducing agent (e.g. sodium dithionite) and preferably Fe(II) ions to the liquid at a pH of above 7.5 or 8 and precipitating elemental selenium from the liquid.
Claims12
A method of reducing the selenium content of wastewater, the method comprising contacting the wastewater with Fe(II) ions, and a dithionite ion (M), at a pH of from 7.5 to 10.5 and in the presence of lime;
- and
- heating the wastewater to a temperature of from 60 to 95° C.,
- wherein the wastewater comprises selenite and selenate,
- wherein the wastewater further comprises from 4000 to 8000 ppm of sulfate,
- wherein the wastewater is purged with nitrogen.
A method of removing selenium from water, the method comprising contacting the water with a dithionite ion at a pH of 7.5 to 10.5;
- and heating the water to a temperature of from 70 to 95° C., wherein the wastewater comprises selenite and selenate, and from 4000 to 8000 ppm of sulfate,
- wherein the wastewater is purged with nitrogen.
Dependencies are inferred from the claim text.