REMOVAL OF TCE AND CHROMATE IN REACTIVE BARRIERS USING ZERO-VALENT IRON: LABORATORY EXPERIMENTS

Key words: groundwater clean-up, chromium, chlorinated hydrocarbons, barriers, reduction

Chlorinated solvents and hexavalent chromium (as chromate) are some of the most serious threats to groundwater resources. Chlorinated solvents have been used for degreasing of metal agents and dry cleaning of clothing, while chro- mate has been used for wood preservation, electroplating and tanning leather. Chlorinated solvents and chromate are highly mobile and toxic pollutants, the chlorinated solvents being persistence in many groundwater environments. At electroplating facilities both pollutants are often observed at the same time.

Chlorinated solvents are chemically degraded in contact with iron surfaces. Chromate can be reduced to a less mobile and toxic compound in contact with iron surfaces. The use of zero-valent iron in reactive barriers is a relatively new remediation technology, which is used in several places especially in the USA. In Europe the technology has until now only been used in a few cases.