PRBsPRBs in the UK:in the UK: New Agency GuidanceNew Agency Guidance

Monkstown Monkstown ZVI &ZVI & New Sequential Reactors New Sequential Reactors

Prof. Robert M. Kalin School of Civil Engineering, Queen’s University Belfast

Belfast N. Ireland UK BT9 5AG

Thanks to some of those in our research group that have contributed in one way or another to the work presented here.

Academic Staff: Dr. M. Larkin, Dr. T. Elliot, Dr. V. Sivakumar, Dr. D. Hughes, Dr. J. McKinley, Dr. B. Kulessa

Research Officers: Dr. Y.S. Yang, Dr. G. Boshoff, Dr. W. Meir-Augustein

Post Doctoral Fellows: Dr. U. Ofterdinger, Dr. R. Doherty, Dr. V. Decroq, Dr. K. Redeker, Dr. F. Keppler, Dr. A. Ferguson, Dr. D. Fairley, Dr. S. Ardichandran, Dr. D. Gibbons, Dr. A. Mahesh, (Dr. J. Barth – SUERC, Dr. J. Hall – Princeton)

Research Assistants: Ms. A. Downey, Mr. K. Dickson, Ms. K. McGeough

Technical Support: Dr. N. Ogle, Mr. M. Matiasek, Mr. E. Tujek, Mr. M. Carey,

PhD Students: Mr. M. Craig, Ms. T. Adotula, Mr. T. Montegue, Ms. M. Archibold, Ms. O. Crowley,

Industrial Collaborators: Nortel, Keller, OCSC, ETI, IP, QUESTOR IAB, EcoMesh Funding Sources: EPSRC, NERC, BBSRC, EU, EA England and Wales, DOENI

Queen’s University Belfast QUESTOR ATU & Environmental Engineering Research Centre

Guidance on the Design, Construction, Operation and Monitoring of Permeable Reactive Barriers

National Groundwater & Contaminated Land Centre report NC/01/51

M. A. Carey, B. A. Fretwell, N. G. Mosley & J. W. N. Smith*

*

Entec (UK) Ltd

Environment Agency, NGWCLC

Technical Advice Prof. Kalin Prof. Jefferies Dr. Boshoff

VChange in UK Legislation

VChange in UK Remediation

VRoute to Commercial Use

VCa. >£100M impact?

Workshops

Monday 21 October-Aberdeen

Wednesday 23 October -Belfast

Friday 25 October -Dublin

Monday 28 October - London

Wednesday 30 October - Cardiff

Tuesday 12 November - Sheffield

Thursday 14 November - Newcastle

Detailed 1Detailed 1--day Guidance Seminarsday Guidance Seminars PRBPRB--Net & First FaradayNet & First Faraday

Training Courses

Environment Agency

7 Regional Offices

Monday 7 October 2002 to

Friday 18 October 2002

DefinitionDefinition

“A Permeable Reactive Barrier is an engineered treatment zone of reactive material(s) that is placed in the subsurface in order to remediate contaminated fluids as they flow through it.

A PRB has a negligible overall effect on bulk fluid flow rates in the subsurface strata, which is typically achieved by construction of a permeable reactive zone, or by construction of a permeable reactive ‘cell’ bounded by low permeability barriers that direct the contaminant towards the zone or reactive media”

Why produce this guidance?Why produce this guidance?

• Provide Agency, consultants and remediationcontractors with good practice guidance;

• Underpin an Agency Enforcement Position onthe regulation of PRBs

• Encourage the effective use of sustainableremediation techniques, including PRBs.

Key principles (1)Key principles (1)

• PRB should be selected when it is the ‘best practicable technique’;

• Guidance applies to a wide range ofcontaminants and PRB designs;

• Framework for development and justificationof PRB design, monitoring regime anddecommissioning arrangements.

Key principles (2)Key principles (2) • Design

– Treatability tests – Pilot scale trials – Modelling

• Hydraulic effects • Residence time and reactivity • Geochemistry and longevity assessment

• Decommissioning

PRB Licensing requirementsPRB Licensing requirements

• Where treatment of contaminated groundwater takes place it requires a WasteManagement Licence (site licence) or PPCPermit, unless: – Exclusion (e.g. not controlled waste) – Exemption (e.g. subject to a discharge

consent - Reg 16, WMLR94) • Agency may take an Enforcement Position

– Works Instruction 4/98 – As amended to include PRBs

What does the EP not extend to?What does the EP not extend to? • Borehole arrays (e.g. ORCTM, HRCTM, nutrient

injection etc) - in situ bioremediation; • Air-sparge / bio-sparge (including sparge

curtains); • Soil solidification / stabilisation; • treatment of waste soil

– all MPL • Low permeability clay / sorption barriers ***

– Not licensable activity • Technical Guidance: May be helpful to above

treatments.

Framework for guidanceFramework for guidance Stage 1: Screening

Preliminary assessment

Stage 2: Design

SI, pilot studies and design

Stage 3: Implementation

Construction

Is a PRB a viable option?

Refine conceptual model and design PRB

Installation of PRB

Stage 4: Operation, maintenance & monitoring

Verification and monitoring

Does PRB manage risks? Does PRB clog? Decommissioning

Sub stage 1

Sub stage 2 etc

PRB installations in the British Isles7 PRBs + 12 Soil Mix installed

10 in Feasibility stages (includes new patents for treatments)

QConst 12/02

Q

Q

QQ

Q

Q

Q

QQ

PRB at proposal / trial stage

Zero-valent Iron (Fe0)

Biological barrier mine water

Granular Activated Carbon (GAC)

New patented treatment CS2

Sequential Abiotic / Biologic

Phyto hydraulic-control PRB

Soil Mix ‘PRB’ (12 known)

Sites not identified on map

(Reproduced courtesy of EnviroMetal Technologies Inc)

Continuous Wall Funnel and Gate

USA more popular UK more popular

Long-term will it be a source term? Can be cleaned out.

OperationOperation

MaintenanceMaintenance

MonitoringMonitoring

DecommisioningDecommisioning

Monitoring objectives:Monitoring objectives:

• Performance assessment – Outflow concentrations / flux

• test against remedial objectives • validate PRB effectiveness • PRB deterioration (fouling)

– Hydraulic controls • By-pass flow • impacts on GW flow regime

– Test conceptual model

Monkstown Monkstown ZVI Site ZVI Site

CL:AIRE TDP Report 4 CL:AIRE TDP Report 4 –– OperationOperation

QUB Report in prep on Maintenance QUB Report in prep on Maintenance and Decommissioning planand Decommissioning plan

Area of Interest

TCE Concentrations Upstream of Reactor

0

50000

100000

150000

200000

250000

300000

350000

400000

450000

Jan-93 Jun-94 Oct-95 Mar-97 Jul-98 Dec-99 Apr-01 Sep-02

Date

TC

E C

on

ce

ntr

ati

on

s (

ug

/l)

GA21 GA19 GA7 BH19

cis 1,2 DCE Concentrations Upstream of Reactor

0

100

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Jan-93 Jun-94 Oct-95 Mar-97 Jul-98 Dec-99 Apr-01 Sep-02

Date

cis

1,2

DC

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ntr

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(u

g/l)

GA21 GA19 GA7 BH19

PRB implementation in PRB implementation in BBelfastelfast/N.Ireland/N.Ireland

TCE Concentrations in Reactor Monitoring Wells

0

5000

10000

15000

20000

25000

30000

35000

40000

Oct-95 May-96 Dec-96 Jun-97 Jan-98 Jul-98 Feb-99 Aug-99 Mar-00 Oct-00 Apr-01 Nov-01

Date

TC

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RB5 RB4 RB3 RB2 RB1

TCE Concentrations in Reactor Monitoring Well (excluding RB5)

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Oct-95 May-96 Dec-96 Jun-97 Jan-98 Jul-98 Feb-99 Aug-99 Mar-00 Oct-00 Apr-01 Nov-01

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RB4 RB3 RB2 RB1

TCE Concentrations in Dow ngradient Monitoring Wells

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Jan-93 Jun-94 Oct-95 Mar-97 Jul-98 Dec-99 Apr-01 Sep-02

Date

TC

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TCE Concs. cis 1,2 DCE

‘Recycled’ plume effect

PRB implementation in Belfast/N.Ireland PRB implementation in Belfast/N.Ireland -- 5 Years Later…..5 Years Later…..

2002: Nortel approached QUB for long-term R&D

4.000 5.000 6.000 7.000 8.000 9.000 10.000 11.000 12.000 13.000 14.000 15.000 16.000 rt0

100

%

n-Hexane (Int. Std.)Ethane

Ethene

c-DCE TCE

1-Butene

c-Butene

t-Butene

VC Propane

Propene

(Water)

TIC Mass 15 -150

Belfast iron, control # 1, 143 hours

TCE Degradation with Fe0 - Products

Pentenes

Retention Time

TCE Degradation Fe0 – GC-MS/IRMS

0.1

1

10

100

0 50 100 150 200 250 300

Time (h)

M a

+ M

g (µ

mol

)

-60

-50

-40

-30

-20

-10

0

10

0 50 100 150 200 250 300

Time (h)

δ 13 C

(‰ V

PDB

)

Belfast iron, control # 1,

TCE

Ethane

Ethene

c-DCE

Acetylene

TCE

Ethane

Ethene

c-DCE

MS IRMS

][1000/

// 00

0

)( 1213

)( 1213

)( 1213

13 ⋅−

= std

stdsample VPDB CC

CCCCCδ

Belfast Iron – QUB EM Images

x 300

x 4500

x 300

x 3000x 3000

x 50

Control EntranceCenter

Monitoring objectives:Monitoring objectives: • Performance assessment

VOutflow concentrations / flux (Gate) Vtested against remedial objectives Vvalidated PRB effectiveness VPRB deterioration (fouling) not threat

VHydraulic control (Funnel) VBy-pass flow – none noted Vimpacts on GW flow regime - negligible

VTest conceptual model

BROWNFIELD REDEVELOPMENT QUB Project for Biologic PRB at Portadown

Portadown Gas Works - Hydrogeology & Modelling - BioGeochemistry - Microbial Ecology - Microbial Genetics - Full-scale implementation - Evaluation

Up to 1500 existing gasworks sites in the UK still requiring remediation

Desk Study

• Location in Northern Ireland

Mourne Mountains

Lough Neagh

Portadown

Old Landfill

Spoil from factory

Gasworks

Petrol Stations

Site Investigation

Portadown Gasworks Site Investigaton

1

2

3

4

5 6

7

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11 12

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43BH7BH8

BH1BH2

BH6

BH5

BH3

BH4

301540 301560 301580 301600 301620 301640 301660 301680

354280

354300

354320

354340

354360

354380

354400

354420

Trial pits

Boreholes

Intrusive SI

6.000 8.000 10.000 12.000 14.000 16.000 18.000 20.000 22.000 24.000 26.000 28.000 rt3

100

%

11.135

11.035

9.402

7.751

7.118 8.785

10.202

22.037

20.837

19.604

16.986 12.619 15.60314.136

12.752

18.320

18.186

20.720

23.404

25.087

27.171

Scan EI+ TIC

3.43e6 RT

99JL2113

Example GC-MS of a soil extract from made ground contaminated with aliphatic compounds.

Complexed CyanideMineral Oil

3-D Multi-level information

Naphthalene

9

10

11

12

13

14

15

16

17

0 500 1000 1500 2000 2500 300

Concentration

Elev

atio

n /m

AO

D

Eh(V) with Depth at BH8

8

9

10

11

12

13

14

15

16

17

-0.15 -0.1 -0.05 0 0.05 0.1 0.15

Eh V

Dept

h AO

Dm

BH8-1

BH8-2

BH8-3

BH8-4 BH8-5

BH8-6

BH8-7

BH8-8

BH8-9

BH8-10

BH8-11

BH8-12 BH8-13

BH8-14

BH8-15

8m

9m

10m

11m

12m

13m

14m

15m

16m

17m

Ground surface

Made Ground

Aquitard 1

Aquifer 1

Aquitard 2

Aquifer 2

Aquifer 2

Silt lens

Glacial Till

End of Borehole

SO2-4

HS -

H S2

HSO

S

-4

Geochemistry groundwater on site is by nitrate – ammonia microbial processes and therefore very little H2S is formed

of

controlled

Microbiological Investigation

Conceptual Geologic Framework

-5

-10

-15

0

5

10

15

20

25

30

500 1000 1500 2000

A B

SITE

AOD (m)

Distance

125 193

FG11

FG10 FG9

K5 286

RIVER

13

Site Lithologies

BH1/2

BH5

BH3/4

BH6

BH7/8

Vertical magnification 3 times

Hydrogeologic Framework

90 190100 120 140 160 180

90

230

100

120

140

160

180

200

220

BH7 BH8

BH1 BH2

BH6

BH5

BH3

BH4

100 110 120 130 140 150 160 170 180 190 200

100

110

120

130

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150

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0m 40mScale

Final Flow Field Pre-Works

Note the effect of underground structures on pathlines.

(off-site migration of plume encountered where modelled predicted)

100

110

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140

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160

170

180

190

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220

100 110 120 130 140 150 160 170 180 190 200

Queen's University Belfast Environmental Engineering Research Centre QUESTOR Centre

Project: Portadown Gasworks Site Investigation

Drawn By: RD

0m 40mScale

Extent of modelled individual contamimant plumes moving from tar well within aquifer 2 over 1.7 years

Phenanthrene 2 methylnaphthalene

Naphthalene Mineral oil (benzene)

mg/L mg/L

mg/L

mg/L

100 110 120 130 140 150 160 170 180 190 200

100

110

120

130

140

150

160

170

180

190

200

210

220

Queen's University Belfast Environmental Engineering Research Centre QUESTOR Centre

Project: Portadown Gasworks Site Investigation

Phenanthrene mg/l

Drawn By: RD

0m 40mScale

Modelled contaminant plumes distribution within made ground after 100 years,

source - Tar well

2 Methylnaphthalene mg/l

Source: Tar Well in Aquifer 2, 500mg/l constant contamination

Mineral oil /naphthalene

BH17.49 BH17.57

BH19.24 BH19.14

BH18.99

BH17.28

BH16.88

BH16.74

100 110 120 130 140 150 160 170 180 190 200

100

110

120

130

140

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0m 40mScale

Modelled Water Table for Site

Pre Excavati on Mode lle d Re su lts

15

16

17

18

19

15 16 17 18 19

Ob s e r v e d h e a d s ( m)

BH7 Multilevel

Fit of Observed

and Modelled

Water Table at Site

Reactor Placement to

Intercept Plume

Laboratory Feasibility Study

R.Kalin R.Kalin

Treatability study using actual site water

Columns at QUB

1-D Flux and Rate

Experiments

2-D Biologic Treatment Feasibility Study

Benzene Degradation in the Biobarrier

Toluene Degradation in the Biobarrier

Rates of BTEX removal for the lab-scale reactor were use in full-scale designed to ensure adequate residence time and hence removal of contaminated substances. (note: Microtox indicates toxicity is removed after only 1 week of pilot scale operation)