29 September 2009:
Toxic heavy metals can be sucked out of soils far more quickly
and efficiently using a powerful new electrical method, the CleanUp
09 conference will hear in Adelaide today.
“Our aim was speed up the established process for
removing metals like lead and cadmium from soil using
electrokinetic methods, so that rapid clean-up can occur when this
is needed to protect community health and safety,” Dr Lisbeth
Ottossen of the Technical University of Denmark, says.
Conventional electrokinesis, developed in the 1980s, works by
using a powerful electrical field to cause ions of heavy metals to
‘flow’ through the soil, drawn to an electrical pole
where they can be gathered and removed. However this process
takes place very slowly and it may take months of treatment to
achieve effective clean-up.
“Where the community’s health and safety are at
stake, or a redevelopment project needs to go ahead, it may be
important to remediate a contaminated site much more quickly than
this,” she explains.
Her team has combined traditional electrokinetic soil
remediation with conventional electrodialysis to produce a newer,
faster and more thorough way of cleansing contaminated soils.
Contaminated soil is diluted with water, washed, stirred and
then exposed to electrical treatment. Experimenting with soils from
a former wood preserving plant, heavily polluted with lead, copper,
chromium and arsenic, the team found that 90 per cent of the
contaminating lead and 99 per cent of the copper could be removed
in the space of about two weeks. The fact that the mixture was more
acidic than the surrounding soil helped in freeing up the metal
ions so they could be removed.
The combined method also removed up to 28 per cent of the
chromium and 65 per cent of the arsenic from the soil. “We
concluded we need to add an enhancement to the solution to achieve
proper remediation of the soil, for these two metals,” she
Dr Ottossen will deliver her paper at 1.40 PM on Tuesday
September 29, 2009.
The CleanUp 09 conference is being held at the Hilton Hotel,
Adelaide from September 28-30.
Dr Lisbeth Ottossen, Technical University of Denmark, +45 42 24 52
Peter Martin, CRC CARE communication, ph 0429 779 228
Conference number: 08 8217 2000 and ask for CleanUp 09