Environmental Engineering Reference
In-Depth Information
liter.(µg/L),.including.TCE.at.up.to.56.µg/L..Much.of.this.contamination.existed.45.
to.60.ft.below.the.water.table.
Initial.testing.showed.that.bimetallic.particles.containing.palladium.performed.
more. effectively. than. nZVI. without. a. catalyst.. Full-scale. treatment. with. nZVI/Pd.
BNP. from. PARS. Environmental. proceeded. in. two. phases.. Phase. I,. in. November.
2005,. entailed. injection. of. 2300. lb. BNP.. Workers. injected. a. slurry. containing. 20.
lb.nZVI/Pd.in.1200.gallons.of.water.(or.~2.g/L).in.each.of.15.Geoprobe™.injection.
points..(Ten.injection.points.were.located.in.the.northern.plume,.and.ive.within.the.
southern.plume.).These.injection.points.targeted.the.aquifer.zone.between.50.and.70.
ft.below.ground.surface.(ft.bgs).in.2-ft.intervals.
The.ield.team.collected.groundwater.samples.for.6.months.after.treatment..The.
concentrations. of. chlorinated. compounds. in. some. wells. increased. after. 1. week,.
potentially.due.to.desorption.from.soil..Concentrations.subsequently.decreased..The.
average. decrease. in. the. concentration. of. total. VOCs. in. all. monitoring. wells. was.
74%;.of.TCE,.79%,.and.of.DCE,.83%..ORP.measurements.indicated.the.general.con-
ditions.in.the.aquifer..Six.months.after.injection,.ORP.levels.had.decreased.slightly.
in. 3. of. 13. monitoring. wells,. but. increased. or. remained. the. same. in. other. wells..
These.data.showed.that.BNP.injection.did.not.create.strong.reducing.conditions.in.
the.aquifer,.possibly.due.to.the.oxygen.in.the.water.used.to.mix.the.BNP.slurry.at.the.
site..pH.levels.were.expected.to.rise.signiicantly.as.a.result.of.treatment;.however,.
the.average.pH.decreased.slightly..Based.on.the.geochemical.data,.the.project.team.
hypothesized.that.the.decrease.in.VOC.concentrations.may.have.resulted.from.dilu-
tion..They.inferred.that.mixing.the.nZVI.slurry.with.a.large.volume.of.aerated.water.
before.injection.passivated.the.nZVI.[32].
Phase.II.occurred.in.January.2006..Workers.injected.a.slurry.containing.500.lb.
BNP. using. the. same. methodology. as. in. Phase. I.. Monitoring. continues. as. of. mid-
2007;.groundwater.quality.standards.have.reportedly.been.achieved.for.some.moni-
toring.wells.
As.the.information.in.Section.10.1.shows,.using.nZVI.has.both.beneits.and.pos-
sible.risks..The.next.section.discusses.the.development.and.use.of.other.nanotech-
nologies.in.environmental.remediation.
0.   otheR teChnologies
Table.10.2. briely. describes. technologies. under. development. for. wastewater. treat-
ment,.environmental.remediation,.and.related.applications..It.categorizes.treatment.
technologies.according.to.whether.they.rely.on.free.nanoparticles.or.nanomaterials.
ixed. in. a. matrix.. This. distinction. may. be. important. with. respect. to. the. potential.
for.exposure.to.inadvertently.released.nanomaterials..Table.10.2.further.categorizes.
treatment. technologies. according. to. their. mode. of. treatment.. Some. technologies.
destroy.contaminants.by.oxidation,.reduction,.or.hydrolysis..Many.such.technologies.
incorporate.nanocatalysts..Other.technologies.separate.contaminants.from.ground-
water.or.wastewater.for.further.treatment.or.disposal.
Table.10.2.indicates.the.development.status.of.each.technology.as.of.late.2007.
—.that.is,.bench.scale,.pilot.scale,.or.full.scale..Bench-scale.tests.are.performed.in.
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