phytoremediation debbie schuttenhelm che 562 11/17/04
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PhytoremediatioPhytoremediationn
Debbie SchuttenhelmDebbie Schuttenhelm
ChE 562ChE 562
11/17/0411/17/04
OutlineOutline
What is phytoremediationWhat is phytoremediation Types and examplesTypes and examples Other removal methodsOther removal methods ProsPros ConsCons
What is What is phytoremediation?phytoremediation?
Using living plants for contaminant Using living plants for contaminant removal, degradation, or containmentremoval, degradation, or containment
Clean up soil and or groundwaterClean up soil and or groundwater Can remove organics, metals, leftover Can remove organics, metals, leftover
pesticides, explosives, radioactive pesticides, explosives, radioactive wastewaste
Used independently or with other Used independently or with other cleanup methods to reduce costscleanup methods to reduce costs
TypesTypes
PhytoextractionPhytoextraction Uptake by plants and accumulation in Uptake by plants and accumulation in
leaves or stemleaves or stem PhytodegradationPhytodegradation
Plants metabolize contaminantsPlants metabolize contaminants RhizodegradationRhizodegradation
Plants promote microbial activity that Plants promote microbial activity that breaks down contaminantsbreaks down contaminants
PhytovolatilizationPhytovolatilization Uptake and transpirationUptake and transpiration
OverviewOverview
MechanismsMechanisms
http://www.itrcweb.org/PHYTO2.pdfhttp://www.itrcweb.org/PHYTO2.pdf
PhytoextractionPhytoextraction Metal hyperaccumulators - Alpine Metal hyperaccumulators - Alpine
pennycresspennycress Concentrate zinc, cadmium, nickel in stems and Concentrate zinc, cadmium, nickel in stems and
leavesleaves Takes in 30,000ppm zinc and 1,500ppm cadmium Takes in 30,000ppm zinc and 1,500ppm cadmium
as opposed to 100ppm and 1ppm, respectivelyas opposed to 100ppm and 1ppm, respectively 30 times as much as usually poisons other plants30 times as much as usually poisons other plants Harvested and burned, ashes sold as high-grade Harvested and burned, ashes sold as high-grade
zinc orezinc ore Also research in adding citrate to soil to make Also research in adding citrate to soil to make
uranium more soluble for 100 times higher uranium more soluble for 100 times higher uptakeuptake
MechanismMechanism
Phyto/RhizodegradationPhyto/Rhizodegradation
Poplar treesPoplar trees Can uptake and metabolize atrazine Can uptake and metabolize atrazine
(toxic herbicide) in soil(toxic herbicide) in soil Also stimulates microbes in soil to Also stimulates microbes in soil to
further degrade contaminantsfurther degrade contaminants Enzyme nitroreductase can break down Enzyme nitroreductase can break down
TNTTNT Saplings bring levels below detectable Saplings bring levels below detectable
limits within a few weekslimits within a few weeks
PhytovolitalizationPhytovolitalization
Indian mustardIndian mustard Take up selenium from the soil, Take up selenium from the soil,
contaminant around oil wells, power contaminant around oil wells, power plants, and mining operationsplants, and mining operations
Convert to dimethyl selenide and Convert to dimethyl selenide and release to atmosphererelease to atmosphere
Less desirable process because Less desirable process because atmospheric effects generally unknownatmospheric effects generally unknown
Continuing researchContinuing research
MTBE – poplar and eucalyptus MTBE – poplar and eucalyptus saplingssaplings
Perchlorate – willows and cedarsPerchlorate – willows and cedars Arsenic – fernsArsenic – ferns Depleted uranium – tumbleweedsDepleted uranium – tumbleweeds DDT – pumpkinsDDT – pumpkins
Other methods of Other methods of removalremoval
Removal and landfilling of Removal and landfilling of contaminated soilcontaminated soil
Incineration of contaminantsIncineration of contaminants Surfactants used to wash Surfactants used to wash
contaminants out of soilcontaminants out of soil Ion exchange, reverse osmosis, other Ion exchange, reverse osmosis, other
methods in contaminated methods in contaminated groundwatergroundwater
Pros of PhytoremediationPros of Phytoremediation
Reduction in landfill volumeReduction in landfill volume 30 tons of ash vs. 5,000 tons soil for 2.5 30 tons of ash vs. 5,000 tons soil for 2.5
acre site, 18in deepacre site, 18in deep Low maintenanceLow maintenance Positive public opinionPositive public opinion Cost benefitsCost benefits
Cost benefitsCost benefits
Costs – water cleanupCosts – water cleanup
http://www.dtsc.ca.gov/ScienceTechnology/http://www.dtsc.ca.gov/ScienceTechnology/TD_REP_Perchlorate-Alternatives.pdfTD_REP_Perchlorate-Alternatives.pdf
ConsCons
Much slower to implement, seasonal Much slower to implement, seasonal processprocess
Not as effective with very high Not as effective with very high concentrationsconcentrations
Limited by root depthLimited by root depth Toxicity of biodegradation products Toxicity of biodegradation products
not always knownnot always known Possibility of contaminants entering Possibility of contaminants entering
food chainfood chain
ReferencesReferences http://www.ars.usda.gov/is/AR/archive/junhttp://www.ars.usda.gov/is/AR/archive/jun
00/soil0600.htm00/soil0600.htm http://ehp.niehs.nih.gov/docs/1995/103-12http://ehp.niehs.nih.gov/docs/1995/103-12
/innovations.html/innovations.html http://www.itrcweb.org/PHYTO2.pdfhttp://www.itrcweb.org/PHYTO2.pdf http://www.epa.gov/tio/download/remed/phttp://www.epa.gov/tio/download/remed/p
hytoresgude.pdfhytoresgude.pdf http://csmonitor.com/2004/0415/p17s02-sthttp://csmonitor.com/2004/0415/p17s02-st
en.htmlen.html
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