纳米铁技术在污染场地土壤与地下水修复中的应用实践

Application

of

Nanoiron

in

Soil

and

Groundwater

Remediation2013

International

Forum

onRestoration

of

Contaminated

SitesManagement

–

Beijing,

ChinaDanielW.

Elliott,Ph.D.,

Senior

ConsultantOctober22,2013AgendaIntroduction

–

Brownfield

challenges

in

ChinaOverview

of

thenZVI

technologyApplications

ofnZVIat

large

contaminated

sitesFuturedirections

ofthe

nZVItechnologyQ

and

AI.

Atale

of

two

titansDifferent

times,

similar

trajectoriesUS

–

post

WWIIChina

–

Great

Leap

ForwardMajor

expansion

of

manufacturingSteel,

metal

products,

&vehiclesChemicals&

pharmaceuticalsPlasticsElectronicsEconomic

growth

wealth,

stability&

environmental

impactsAll

environmental

media,

esp.

air

&

waterCreated

“Brownfield”

sitesUnderscored

creation

of

“regulatoryinfrastructure”

to

respond

to

crisisI.

Brownfield

management

in

the

USCERCLA

1980Identify

PRPs

&

“polluter

pays”Liability

is

“strict,

joint

and

several,

andretroactive”Ifno

PRPs,

EPA

leads

cleanupSARA

1986Reauthorized

&

increased

“Superfund”Permanent

&

innovative

remediesGreater

involvement

by

StatesBrownfield

Act2002Innocent

purchaserdue

diligence

defenseSmall

business

liability

exemptionNo

federal

enforcement

or

duty

to

cleanupcontamination

from

off-site

sourcesCVOC,

CBs,pesticides,

dioxins/furans425,000

Brownfield

sites

inUS2,000,000

hectares

impactedI.

Brownfield

management

in

ChinaRegulatory

infrastructureandguidance

being

built2006:Pollution

surveyinitiated

byMEPNational

inscope;

200,000

soil

and

groundwater

samples2011:Landmark

investmentplans

byMEPNational

12th

Five-Year

Plan

for

SoilsEnvironmental

Protection

30

billion

CNY

($5

billion

USD)National

Planfor

Underground

Water

Pollution

Prevention

34.7billion

CNY

($5.6billion

USD)300,000

–600,000

Brownfield

sitesTypical

contaminantsMetals,

petroleum,

inorganic-N,

CN-,

phenols…Not

much

data

on

possible

recalcitrant

contaminantsI.

CommoncontaminantsatBrownfield

sitesAs,

Cr,

Pd,

Hg,

Ni,

ZnMeCl2,

CHCl3,

CCl4VC,

DCEs,

TCE,PCEAldrin,

dieldrinChlordaneDDT,

DDE,

DDDBHC

(HCH)PCBsAcetoneBenzeneTolueneXyleneNapthaleneSolventsHighlyRecalcitrant

Organics(POPs)MetalsChlorinatedVOCs(CVOCs)Challenging

totreatVERY

difficult

totreat!Watercrisisin

ChinaGW

resources

akey

componentUneven

distribution

-

30%

North,

70%South2

out

of

3

cities

rely

on

GWAvailability

isseriously

threatenedOver-extraction

&

urbanizationInsufficient

regulatory

infrastructureThe

Economist,

10-12-13

(pg.

18)“Accordingto

the

land

ministry,

more

than

half

of

the

groundwater

in

northern

China

is

toodirty

for

people

to

wash

in,

let

alone

drink,

andsome

isso

poisonousitcannot

even

be

used

in

the

fields.”RecalcitrantcontaminantsResistant

to

degradation

processeso

Abiotic,

biotic,

natural

attenuationGenerally

lowaqueous

solubilityTend

to

partition

into

aquifer

matrix&

sedimentsTend

to

bioaccumulateEffects

are

exacerbated

by

lowKComplicates

remediation

effortIncreases

treatment

timeand

costI.

Two

issues=one

majorBrownfield

challengeNeed

innovative

newtechnologies

like

nZVI!II.

Types

ofZVIused

inremediationNanoscale,

nZVI

(<100

nm)Application:

In-situ

inj

for

sourcearea

&

dissolved

plumeMicroscale,

mZVI(1-100

m)Application:

Backfill,

limited

in-situ

inj.Granular,

gZVI

(mm)Application:

PRBs,

backfill,

etc.gZVIReactivitymZVI nZVISpecific

surfacearea,m2/gII.

BasisofnZVIaction

–conceptual

modelFe0

Fe0

+ 2e-Cathode2H+ + ½

O2 + 2e-2e- +

2H2O

H2Redox

reactionsAnode

H2O+

2OH-Core-shell

modele-

transfer

across

oxide

layerContaminant

degradation

bynZVI

is

surface-mediatedII.

Varietyofiron

nanoparticlesBarenZVI

&nFe-oxidesBimetallics

(Fe/Pd,etc.)Supported

nZVICarbon

or

polymeric

bead

substrateEmulsified

ZVI(eZVI)o

nZVI

or

mZVI

within

emulsified

oilmicellesSurface-modified

nZVISurfactant/polymer-based

surface

architecturesPolyacrylic

acid

(PAA)

stabilized0%

PAA 20%

PAAII.

Typical

contaminants

degradedbynZVIEthenesPCETCEcis-1,2-DCEtrans-1,2-DCE1,1-DCEVCMethanes*PCM

(CT)TCM

(CF)TBMPropanes1,2,3-TCP1,2-DCPDBCPPOPs-HCH

(BHC)DDTCBPCBEthanes*1,1,2,2-TeCA1,1,1,2-TeCA1,1,2-TCA1,1,1-TCA1,1-DCACFC

11CFC

113EDBOtherPerchlorateNDMARedox-amenable

Mex+*

1,2-DCA,

CA,DCM,

CM

not

treated

by

ZVI

aloneII.

ExampleofnZVI

reactivityHHClClClHHCl

Cl

HClH641532

-HCH-HCH,

BHC,

“lindane”

–

a

classic

organochlorine

pesticide10MM

metric

tons

used

globally

from

1940s

into

1990sRecalcitrant,

low

aq.

soland

highsorption

potential

Major

remediationchallenge

in

soils,

sediments,GW

Poor

candidate

for

bioremediation0.000.501.001.502.002.500612

18ElapsedTime(hrs)2430Concentration(mM)g-HCH

TeCCH26.5

g/L

TYPE

IInZVI,

100

nm0.900.800.700.600.500.400.300.200.100.0001020

30

40Elapsed

time

(hrs)5060Conc

in

EtOH,

mMg-HCHControlsg-PeCCH26.5

g/L

TYPE

IIInZVI,

50

nmTetra-chloro

intermediatePenta-chlorointermediateIII.

Summary

ofmajorfield-scale

nZVI

projectsData

from

Karn

etal.

(2009)

Environ.

Health

Perspec.

Vol.

117(12),

pp.

1823-1831.44

Field-scale

applicationsCVOCs

typicallythe

target39%

PCE,

84%TCE,

55%

DCEs,27%

VCTypically50-150

kg

nZVI,

10-20

g/L4,500

kg

nZVI

at

Quebec,

CanadaIII.

Field-scaleresults

atTrenton,NJ,USAArea

3III.

Pre-injection

conditions

atArea

3Area3a

formersourceareaHistoric

(pre-1995)

TCE

>1,000

g/L

in

groundwater2007:

TCE

~200

g/L;

c-DCE

~45

g/L;

VCnon-detectField

parameters:o

D.O.

~0-2

mg/L;

ORP

~+200

mV;

pH

~4.5-5.5Surficial

aquiferimpacted3-9

m

bgs

but

lower

Kzone

at

2.5-3.5

m

bgsSilty

sands,

some

clays,

saprolitic

layer

above

bedrockKeyhydrogeological

parameters:o

K

~1.95

x

10-3

to

5.8

x

10-2

m/so

i

~0.01;

v

~0.3-3

m/d

(110

-

1,100

m/yr)EffectivenessofnZVIinlower

permeability

zone?III.

Geoprobe

injection

strategyatTrenton750

g/L

nZVI

in

19

L

buckets2-570

L

poly

tanks,

20

g/L

nZVI9-11

kg

nZVI

per

boringTotal

injected

mass

=

500

kg

nZVIB-8InjectiontransectsIII.

Trenton

injection

resultsWithin

Area

3,

significant

redox

chemistry

ORP:

~

+200

mV

to

-300

mVo

pH:

~0.5

to

1

std

unit

increaseAvg.test

area

results:Injection TCE(g/L) c-DCE

(g/L) t-DCE(g/L)Pre 220 45 NDPost

(6months) 145 10 10Lessons

learned:Secondary

biotic

reduction

may

be

more

important

than

nZVIMultipletreatments

would

berequired,

dose

likelytoo

lowo

nZVItraveled

>30ft,

evident

at

boring

B-8

near

buildingDirect

push

delivery

was

successful,

better

than

using

wellsDespitecomplications

from

lowKzoneIII.

Quebec,Canada

–Golder

AssociatesCanadian

Military

BasePlumeCharacteristics4kmlong0.8

km

wide40

m

deepTCEMultiple

sourcesPilottestzone:100m100m40m4,500

kg

Golder

nZVI/Pd

(0.1%)Slurry

density

10-40

g/L80,000L

soy

protein

dispersantIII.

Layout

ofnZVI

injection

plan

-

QuebecIII.

Quebec,Canada

-

GolderLessons

Learned:After

injection,

ORPdeclined

to

<-400

mVMicrobiological

diversity

shiftedTCE

concentrations

declined

>80%

after10

months,

no

daughters

observedAfter

10

months,

c-DCE

concentrationsrose,

suggesting

biotic

mechanismLower

K

silts

not

problematicFull-scale

100,000

kg

nZVI/Pd

treatmentprogram

is

plannedIV.

Future

directions

ofnZVIStrong

research

and

applications

interest

innZVI1,400

peer-reviewed

papers

and

countingKey

issuesRelative

scarcity

ofnZVImanufacturers

and

lackofconsistent

QA/QCprocesses/dataSubsurfacedelivery

and

distribution

challengesEnhancing

understanding

of

fate,transport,

reactivelongevity,

andpotential

exposure

to

nZVIRegulatory

infrastructure

needed?nZVI

best

attributes…so

farExcellent

reactivitytowards

abroad

arrayofredox-amenable

contaminantsTreating

high

concentration

“hot-spots”Promising

forrecalcitrant

chemicals

in

GW,

sediments,

etc.Technology

combinationsIV.

NANOREMWhatisNANOREM?28

partners:

universities,

nationallabs

&

RPs4-yrs

beginning

February

2013

with

€10MM

EUfundingNANOREM

goals:Identification

of

nanoremediation

approaches

that

can

achieve

astep-change

increase

inpractical

performanceLower

cost,

commercially

relevant

scales,

define

the

“implication