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Maectite

What is MAECTITE®?
MAECTITE® is a patented chemical fixation process designed for heavy metal pollutants.

When is it Appropriate to Use MAECTITE®?
All heavy metal contaminated waste materials and debris that fail Toxicity Characteristic Leaching Procedure (TCLP) criteria have proven responsive to the MAECTITE® treatment process.1 Metals and compounds successfully rendered non-hazardous according to the Resource Conservation and Recovery Act (RCPA) definition include lead, cadmium, arsenic, chromium, selenium, and barium. Additional substances responsive to MAECTITE® are copper, nickel, zinc, cyanide, and sulfide.1 Testing shows MAECTITE® is also effective in rendering low-level radioactive nuclides as a non-leachable material.1

The MAECTITE® process is proving successful on both small and large contamination sites. It is used to treat metal-contaminated soils, solids, sludges or aqueous wastes from the manufacture and use of batteries, paints, pigments, leaded glass, tetraethyl lead, photographic materials, wastes from primary and secondary lead smelting operations, shooting range soil, lead and cadmium contaminated wastes from foundries, chromium ore, ceramic frit sludge, nickel cadmium battery plant sludge and heavy metal contaminated soil and marshlands.1

The method is also proven successful with a variety of matrix types, including gravelly sandy soil, clay, red soils, ash, foundry sand, and sediments or sludges.1

Does MAECTITE® Have Government Approval?
MAECTITE® was accepted into the USEPA Superfund Innovative Technology Evaluation (SITE) program in 1992. In 1991 it was also nominated for the President’s Environment and Conservation Challenge Award.1 That same year the MAECTITE® process was selected by USEPA as one of six technologies for inclusion in the US/German Bilateral Agreement as part of the environmental technology demonstration and information exchange program.

How Does MAECTITE® Work?
The principle behind the MAECTITE® process is a chemical bonding that creates a stable mineral mix resistant to leaching.

MAECTITE® involves a three-step process converting leachable metals into mineral crystals that significantly lower solubility of the polluting metal. In doing so the treated soil fits within acceptable waste matrix set by the EPA.1

In its first step a proprietary (patented) chemical is blended with the lead-contaminated material. In the second step a proprietary liquid reagent (MAEPRIC®) is blended into the mixture. An additional oxidation step may be required to reduce multi-valent metals. Curing the prepared mixed typically takes 3 to 5 hours under standard temperature and pressure conditions.

Can MAECTITE® be Used at the Pollution Site?
The most common application of MAECTITE® is ex situ (off-site) treatment which allows greater control under some conditions. Ex-situ treatment has been successfully applied to wastes amounting to only a few drums up to a project requiring 170,000 tons of treatment at a production rate of 2,000 tons per day.1

Several in-situ processing techniques are available depending on topography and near surface soil conditions. Projects range from little as 300 cubic yards treated to a depth of one foot to over 11,000 yards to a depth of 13 feet.

Current capabilities now allow treatment to take place at much greater depths and under water tables.

Is the MAECTITE® Process Expensive?
The cost-effectiveness of this process depends upon a number of site-specific factors:

  • Treatability studies and determination of reagent dosage requirements.
  • Physical handling characteristics of contaminated material.
  • Treatability studies and determination of reagent dosage requirements.
  • Physical handling characteristics of contaminated material.
  • Treatment system sizing and material variability.
  • Ease of site access.
  • Transportation and disposal costs for treated material.
  • Site support requirements.
  • Waste quantities (economy of scale).
  • Ancillary site tasks additional to treatment
References
  1. Maecite Chemical Treatment Process, Stevenson Environmental Services, Inc, www.sevenson.co, retrieved October 16, 2014.