Removal Technologies

Removal Technologies

In response to finding perchlorate at low levels in water, private industry, in cooperation with the federal government, developed and is currently using sophisticated new technologies for removing perchlorate from surface and groundwater supplies.

Aggressive efforts to prevent perchlorate from seeping into groundwater and other water sources include the ongoing use of barriers, wells, pipes and water treatment facilities.

Treatment Technologies

There currently are two major technologies used to treat large volumes of water that contain perchlorate: ion exchange and biological treatment. Other technologies are currently being developed and employed, including membrane filtration and electrodialysis.

Ion Exchange

Ion exchange technology uses a resin to absorb perchlorate and remove it from water. Contaminated water is pumped through a system of resin "beds," which are up to six feet in diameter and up to six feet high. As negatively charged perchlorate is captured on the positively charged resin, it releases chloride, a component of table salt, in its place.

Biological Treatment

Biological treatment is a process that uses microorganisms to break down perchlorate into other components. Contaminated water and carbon sources such as alcohol or corn syrup are placed in a tank or underground, where microorganisms break down the perchlorate and carbon into two primary components, carbon dioxide and chloride.

Membrane Filtration

Two technologies, reverse osmosis and nanofiltration, both involve forcing water through a semi porous polymer membrane. In reverse osmosis, artificial pressure is applied on one side of the membrane, forcing water to migrate through the membrane wall, leaving perchlorate and most other dissolved salts behind. Nanofiltration is a similar technique using membranes with slightly larger pores. Fouling membrane filters remains a concern for both reverse osmosis and nanofiltration technologies.

Electrodialysis

Currently under development, electrodialysis treatment passes water through different membranes while exposing it to an electric field. The electric field separates the perchlorate from the stream of treated water. The perchlorate-containing brine is then appropriately discarded.

Read case studies of how these removal technologies are being implemented »