(Metals Immobilization and Decontamination of Aggregate Solids)
PSI Technologies has developed a technology for metals immobilization and decontamination of aggregate solids (MeIDAS) (see figure below). The technology involves a modified incineration process in which high temperatures destroy organic contaminants in soil and concentrate metals into fly ash. The bulk of the soil ends up as bottom ash and is rendered nonleachable. The fly ash is then treated with a sorbent to immobilize the metals, as determined by the toxicity characteristic leaching procedure. The MeIDAS process requires a sorbent fraction of less than 5 percent by soil weight.
Standard air pollution control devices clean the effluent gas stream. Hydrogen chloride and sulfur dioxide, which may be formed from the oxidation of chlorinated organics and sulfur compounds in the waste, are cleaned by alkaline scrubbers. Fly ash is captured by a particulate removal device, such as an electrostatic precipitator or baghouse. The only solid residues exiting the process are treated soils, which no longer contain organics and will not leach toxic metals.
The MeIDAS process treats organics and heavy metals in soils, sediments and sludges. The process has been effective in treating arsenic, cadmium, chromium, lead, nickel, and zinc.
The MeIDAS process is applicable to wastes contaminated with a combination of volatile metals and complex organic mixtures of low volatility. Possible MeIDAS process applications include battery waste sites and urban sites containing lead paint or leaded gasoline, or chemical or pesticide manufacturing facilities contaminated with organometallics.
This technology was accepted into the SITE Emerging Technology Program in July 1991. Bench-scale testing under the SITE Program was completed in July 1992. The testing showed that organic, lead, and arsenic wastes could be successfully treated with less sorbent (1 to 10 percent of the soil by weight) than previously anticipated. Pilot-scale testing occurred in October 1992 and was completed in May 1993. The Emerging Technology Report has been submitted to EPA for review.
Initial testing, conducted under the EPA Small Business Innovative Research program, has demonstrated the feasibility of treating wastes containing arsenic, cadmium, lead, and zinc.
EPA PROJECT MANAGER:
Mark Meckes
U.S. EPA
National Risk Management Research Laboratory
26 West Martin Luther King Drive
Cincinnati, OH 45268
513-569-7348
Fax: 513-569-7328
TECHNOLOGY DEVELOPER CONTACT:
Joseph Morenc
PSI Technologies, A Division of Physical Sciences Inc.
20 New England Business Center
Andover, MA 01810
508-689-0003
Fax: 508-689-3232