Environmental Engineering Reference
In-Depth Information
Researchers. performed. approximately. 200. jar. tests. on. groundwater. samples. con-
taining.total.VOCs.at.over.100.mg/L,.including.approximately.80.mg/L.PCE.and.
20.mg/L.TCE.
The.tests.showed.that.bimetallic.particles.comprising.nanoscale.iron.coated.with.
about.1.wt%.palladium.were.more.effective.than.nZVI.in.the.short.term,.effecting.
rapid.reductions.in.concentrations.of.chlorinated.VOCs.at.iron.concentrations.of.2.
to.5.g/L..In.one.test,.2.g/L.nZVI/Pd.reduced.the.PCE.concentration.from.approxi-
mately.70.mg/L.to.near.detection.limits.in.2.weeks..nZVI.without.palladium.showed.
only.partial.treatment.within.2.weeks..Benzene.was.not.effectively.treated,.and.in.
fact,. benzene. was. generated. from. the. reduction. of. 1,2-dichlorobenzene.. Site. soils.
did.not.seem.to.affect.treatment.
Work.then.proceeded.with.a.pilot.test.to.verify.the.initial.results.under.ield.con-
ditions,.assess.geochemical.changes.in.the.aquifer.during.treatment,.and.evaluate.the.
transport.of.nZVI,.thereby.providing.a.basis.for.full-scale.design..The.pilot.began.
with.slug.tests.and.tracer.tests.to.provide.information.on.how.the.groundwater.low.
could.transport.nZVI..Based.on.the.results.of.the.bench-scale.tests,.the.design.team.
planned.to.inject.2.gallons.per.minute.(gpm).of.a.~3000-gallon.nZVI.slurry.contain-
ing.100.kg.nZVI.over.3.to.4.days..The.reagent.arrived.at.the.site.as.a.parent.slurry.
and. was. diluted. with. water. on. site. to. prepare. a. solution. containing. 10. g/L. nZVI..
The.parent.slurry.contained.20%.powdered.soy.to.act.as.an.organic.dispersant..Most.
batches.contained.1%.palladium;.the.last.few.injections.did.not..The.target.
in situ
.
concentration.of.nZVI.was.2.g/L.[80].
Presumably. due. to. the. heterogeneity. of. the. aquifer. materials,. the. ield. team.
could.not.achieve.the.planned.injection.rates..A.total.of.2665.gallons.of.nZVI.slurry.
was.injected.at.a.rate.of.0.15.to.1.54.gpm.over.a.period.of.22.days.
Initial.test.results.were.available.as.of.this.writing..Based.on.data.from.moni-
toring. wells. within. 10. to. 20. feet. (ft). of. the. injection. well,. treatment. reduced. the.
concentrations.of.PCE.by.38.to.88%.and.TCE.by.30.to.70%.within.4.weeks..The.
concentrations.of.breakdown.products.methane.and.ethane.increased,.as.did.the.con-
centration.of.DCE..Measurements.after.8.and.12.weeks.indicated.stable.or.increas-
ing.concentrations.of.the.target.contaminants,.likely.originating.from.an.untreated.
source.area.up-gradient.from.the.test.area.
Plans.for.full-scale.treatment,.including.additional.means.to.treat.benzene,.are.
under.development.
0...
naal air engineering station, new Jersey
Chlorinated. compounds. contaminate. groundwater. in. two. areas. of. the. Naval. Air.
Engineering. Station. (NAES). in. Ocean. County,. New. Jersey.. The. U.S.. Navy. used.
BNP.to.treat.the.groundwater.[29,.32],.performing.a.bench-scale.test.in.2001,.pilot.
work.in.2003,.and.full-scale.remediation.in.2005.and.2006.
The.NAES.is.underlain.by.a.coastal.plain.aquifer,.consisting.of.sand.with.some.
clay.and.gravel..The.depth.to.the.water.table.is.approximately.15.ft..Groundwater.con-
tains.PCE,.TCE,.1,1-trichloroethane.(TCA),.and.degradation.products.such.as.DCE.
and.vinyl.chloride.(VC)..Total.VOC.concentrations.ranged.up.to.360.micrograms.per.
