For a number of years, elemental iron or zero valent iron (ZVI) has been used to treat ground water and surface water to remove a number of pollutants (e.g., mercury, arsenic, selenium, chromium (VI), chlorinated hydrocarbons, etc.). The methods for bringing the ZVI in contact with the contaminant have varied from direct addition of the iron to the water to the construction of underground permeable reactive barriers containing iron particles.
More recently, Liberty Hydro, Inc. has developed a unique ZVI delivery system for the removal of heavy metals and selenium from water. The ZVI Blue TM system is a patented process in which finely-divided ZVI is attached to an open-pore polymer foam. The foam media allows easy flow of the water while enabling adequate contact and reaction time with the ZVI.
In all ZVI applications, iron acts as a strong reducing agent and, when it is in the finely-divided form, is particularly effective at reacting with low levels of contaminants. In the case of selenium, the ZVI Blue TM system will effectively reduce all water-soluble forms of selenium and immobilize it as elemental selenium on the surface of the iron. The used ZVI Blue TM media can then be safely sent to the landfill.
Liberty Hydro has also developed customized blends of its reactive media and can install its proprietary technology within a properly-designed treatment train to assure compliance with applicable effluent discharge standards.