Selenate Removal From Waste Water

Two processes for removing highly toxic selenium are available for licensing from the U.S. Geological Survey. Microbial agents are used to naturally respire the selenium compounds selenate and selenite. The microorganisms are endemic species, not genetically engineered, that are utilized to remove selenium from toxic irrigation water and restore water quality. The resulting product of the processes is elemental selenium, which is not mobile in the natural environment.

The patented methods use a two-zone system; the first zone removes nitrate which inhibits the reduction of selenate; the second converts the selenate to elemental selenium. In the first zone, aerobic conditions facilitate the removal of nitrate by assimilation into biomass. In the second zone, anoxic conditions enable selenate-respiring microorganisms to perform the conversion of selenate to elemental selenium. Nutrients required by the microorganisms are produced through the waste water treatment, so no additional, external materials are needed.

Potential commercial uses include removing selenate and selenite from:

• Agricultural irrigation and drainage waters
• Petroleum refinery waste waters
• Mine tailings and drainages

U.S. Geological Survey
Branch of Business Development
500 National Center
Reston, VA 20192
phone: 703-648-4344
fax: 703-648-4706
E-mail: Branch of Business Development