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
Q
Q
Q
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
200
300
400
500
600
700
800
900
1000
Jan-93 Jun-94 Oct-95 Mar-97 Jul-98 Dec-99 Apr-01 Sep-02
Date
cis
1,2
DC
E C
on
ce
ntr
ati
on
(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
E C
on
ce
ntr
ati
on
s (
ug
/l)
RB5 RB4 RB3 RB2 RB1
TCE Concentrations in Reactor Monitoring Well (excluding RB5)
0
20
40
60
80
100
120
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
E C
on
ce
ntr
ati
on
s (
ug
/l)
RB4 RB3 RB2 RB1
TCE Concentrations in Dow ngradient Monitoring Wells
0
1000
2000
3000
4000
5000
6000
7000
Jan-93 Jun-94 Oct-95 Mar-97 Jul-98 Dec-99 Apr-01 Sep-02
Date
TC
E C
on
cen
trati
on
s (
ug
/l)
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
8
9
10
11 12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
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
140
150
160
170
180
190
200
210
220
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
120
130
140
150
160
170
180
190
200
210
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
150
160
170
180
190
200
210
220
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)