Mapua Contamination New Zealand

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Mapua Contamination New Zealand

• By
• Thomas Pettyt and
• Patrick Binanga

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Contents

• Location of the Site
• Site History
• What were the main contaminants?
• Initial Stage of Remediation
• How Mechano-Chemical Dehalogenation (MCD) works?
• Impact on the Community
• Conclusions

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Location of the site

• Mapua is a coastal village at the top of the
  south island of New Zealand.
• The remediated site, is adjacent to the Waimea
  Inlet and the Mapua Channel

Contaminated Area
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Site History

• Fruitgrowers chemical company (FCC) were in
  operation from 1932 to 1988
• Produced pesticides, herbicides and fungicides
• From the 1950s areas of Mapua were used by FCC as
  landfill sites.
• In the early 1990s Tasman District Council (TDC)
  conducted many surveys and investigations on the
  FCC sites. These found significant evidence of
  contamination.
• Early containment steps were taken such as in
  1992 a clay wall was built to reduce discharge of
  contaminants into groundwater.
• But in 1997 the Government decided they would
  prefer the site to be remediated rather than
  contained.

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What were the main contaminants?
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Initial Stage of Remediation

• Funding was provided in 1999 to begin work on the
  remediation of the site.
• The first step involved finding the detailed
  characteristics of the site material.
• Three methods of remediation were considered
• Indirectthermal desorption (ITD)
• Ex-situ bioremediation
• Mechano-Chemical Dehalogenation (MCD)
• ITD and MCD were the only feasible methods with
  MCD becoming the preferred option due to lower
  cost.

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How Mechano-Chemical Dehalogenation (MCD) works?
Reaction Taking Place within milling process
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MCD

• Advantages

• Disadvantages

• High Production Rate (3T/hr)
• Relatively Compact and Mobile
• Inexpensive
• Robust

• Material must be dried
• High noise and vibration
• Final treated material requires mixing and
  amendments to be replaced into environment

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Impact on the Community

• Improper destruction of old buildings containing
  asbestos
• Poor operation of carbon filters causing a poor
  local environment
• Groundwater problems involving use of copper
  sulphate, diammonium phosphate and urea during
  remediation
• Noise generated above the levels agreed before
  remediation began
• Government therefore agreed to fund free health
  checks for local residents

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Conclusions

• Total cost of 12 million provided a clean
  environment with the final batch of contaminated
  soil treated in July 2007
• Complexity of surroundings provided many issues
  during clean-up
• Methods used were problematic due to inexperience
• Some parties felt remediation was not the best
  option

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Any Questions?

• Thank you for listening