case study: how to avoid failures in the design and ......sustaintech –saskatoon, sk march 21,...
TRANSCRIPT
![Page 1: Case Study: How to Avoid Failures in the Design and ......SustainTech –Saskatoon, SK March 21, 2019 Kevin French Case Study: How to Avoid Failures in the Design and Installation](https://reader034.vdocument.in/reader034/viewer/2022043020/5f3bfebce19b604a7259a241/html5/thumbnails/1.jpg)
SustainTech – Saskatoon, SK
March 21, 2019
Kevin French
Case Study: How to Avoid Failures in the Design
and Installation of Permeable Reactive Barriers
![Page 2: Case Study: How to Avoid Failures in the Design and ......SustainTech –Saskatoon, SK March 21, 2019 Kevin French Case Study: How to Avoid Failures in the Design and Installation](https://reader034.vdocument.in/reader034/viewer/2022043020/5f3bfebce19b604a7259a241/html5/thumbnails/2.jpg)
Presenter
Kevin French, P.Eng
• Vice President, Vertex Environmental Inc.
• B.A.Sc., Civil/Environmental Engineering, University of Waterloo
• 30+ years environmental engineering; 25 in consulting and 5 as a
remedial contractor
Special thanks to Milestone Environmental
Contracting Inc. who were our partners for
this project.
Vertex Environmental Inc.
• Founded in 2003
• Specialized Environmental Remediation
Contracting
• High Resolution Site Characterization (HRSC)
![Page 3: Case Study: How to Avoid Failures in the Design and ......SustainTech –Saskatoon, SK March 21, 2019 Kevin French Case Study: How to Avoid Failures in the Design and Installation](https://reader034.vdocument.in/reader034/viewer/2022043020/5f3bfebce19b604a7259a241/html5/thumbnails/3.jpg)
Vertex Environmental Inc.
![Page 4: Case Study: How to Avoid Failures in the Design and ......SustainTech –Saskatoon, SK March 21, 2019 Kevin French Case Study: How to Avoid Failures in the Design and Installation](https://reader034.vdocument.in/reader034/viewer/2022043020/5f3bfebce19b604a7259a241/html5/thumbnails/4.jpg)
Presentation Overview
• Permeable Reactive Barriers
• Overview of Site Conditions
• Preliminary Design & Bench-Scale Testing
• High-Resolution Site Characterization
• Updated Final Design
• Full-Scale Installation
• Quality Assurance / Quality Control
• Performance Monitoring
• Lessons Learned
• Questions
![Page 5: Case Study: How to Avoid Failures in the Design and ......SustainTech –Saskatoon, SK March 21, 2019 Kevin French Case Study: How to Avoid Failures in the Design and Installation](https://reader034.vdocument.in/reader034/viewer/2022043020/5f3bfebce19b604a7259a241/html5/thumbnails/5.jpg)
Permeable Reactive Barriers (PRBs)
![Page 6: Case Study: How to Avoid Failures in the Design and ......SustainTech –Saskatoon, SK March 21, 2019 Kevin French Case Study: How to Avoid Failures in the Design and Installation](https://reader034.vdocument.in/reader034/viewer/2022043020/5f3bfebce19b604a7259a241/html5/thumbnails/6.jpg)
Permeable Reactive Barriers (PRBs)
• PRBs intercept and treat
contaminated groundwater
plumes (passive)
• Allow groundwater to flow through
unimpeded
• Different reactive media for
different contaminants
• Original zero-valent iron (ZVI)
PRBs (“Iron Walls”) installed in
mid-1990 still functional
• Can be dug or injected
• Sustainable (no energy use to
operate)
![Page 7: Case Study: How to Avoid Failures in the Design and ......SustainTech –Saskatoon, SK March 21, 2019 Kevin French Case Study: How to Avoid Failures in the Design and Installation](https://reader034.vdocument.in/reader034/viewer/2022043020/5f3bfebce19b604a7259a241/html5/thumbnails/7.jpg)
Overview of Site Conditions
![Page 8: Case Study: How to Avoid Failures in the Design and ......SustainTech –Saskatoon, SK March 21, 2019 Kevin French Case Study: How to Avoid Failures in the Design and Installation](https://reader034.vdocument.in/reader034/viewer/2022043020/5f3bfebce19b604a7259a241/html5/thumbnails/8.jpg)
Overview of Site Conditions
![Page 9: Case Study: How to Avoid Failures in the Design and ......SustainTech –Saskatoon, SK March 21, 2019 Kevin French Case Study: How to Avoid Failures in the Design and Installation](https://reader034.vdocument.in/reader034/viewer/2022043020/5f3bfebce19b604a7259a241/html5/thumbnails/9.jpg)
Overview of Site Conditions
• Contamination identified in 1998
• Municipality purchased in 2008 and converted to parking lot
• Main groundwater contaminants were tetrachloroethylene
(PCE) and its degradation products
• No DNAPL suspected
• Main pathway of concern was groundwater flow through
overburden
• Remedial objective was to prevent plume of contaminated
groundwater from continuing to migrate
![Page 10: Case Study: How to Avoid Failures in the Design and ......SustainTech –Saskatoon, SK March 21, 2019 Kevin French Case Study: How to Avoid Failures in the Design and Installation](https://reader034.vdocument.in/reader034/viewer/2022043020/5f3bfebce19b604a7259a241/html5/thumbnails/10.jpg)
Overview of Site Conditions
PCE concentrations in
groundwater April 2012
1000
100
500
![Page 11: Case Study: How to Avoid Failures in the Design and ......SustainTech –Saskatoon, SK March 21, 2019 Kevin French Case Study: How to Avoid Failures in the Design and Installation](https://reader034.vdocument.in/reader034/viewer/2022043020/5f3bfebce19b604a7259a241/html5/thumbnails/11.jpg)
Overview of Site Conditions
• Geology:
– Sand and gravel fill with occasional cobbles
– Native soil was sand, silty sand and silty clay till
– Some reported “flowing” sands
– Clay till served as “confining layer” over limestone / dolostone bedrock
– Overburden thickness was approximately 6 to 7 mbgs
• Hydrogeology:
– Water levels in the overburden at approx. 2.4 to 3.4 mbgs
– Horizontal hydraulic gradient of approx. 0.03 to 0.06
– Hydraulic conductivity of approx. 1.2E-07 to 3.5E-04 m/s
– Estimated groundwater flow velocity of 40 m/yr
![Page 12: Case Study: How to Avoid Failures in the Design and ......SustainTech –Saskatoon, SK March 21, 2019 Kevin French Case Study: How to Avoid Failures in the Design and Installation](https://reader034.vdocument.in/reader034/viewer/2022043020/5f3bfebce19b604a7259a241/html5/thumbnails/12.jpg)
Overview of Site Conditions
Geologic Cross-Section
![Page 13: Case Study: How to Avoid Failures in the Design and ......SustainTech –Saskatoon, SK March 21, 2019 Kevin French Case Study: How to Avoid Failures in the Design and Installation](https://reader034.vdocument.in/reader034/viewer/2022043020/5f3bfebce19b604a7259a241/html5/thumbnails/13.jpg)
Preliminary Design & Bench-Scale Testing
![Page 14: Case Study: How to Avoid Failures in the Design and ......SustainTech –Saskatoon, SK March 21, 2019 Kevin French Case Study: How to Avoid Failures in the Design and Installation](https://reader034.vdocument.in/reader034/viewer/2022043020/5f3bfebce19b604a7259a241/html5/thumbnails/14.jpg)
Preliminary Design
![Page 15: Case Study: How to Avoid Failures in the Design and ......SustainTech –Saskatoon, SK March 21, 2019 Kevin French Case Study: How to Avoid Failures in the Design and Installation](https://reader034.vdocument.in/reader034/viewer/2022043020/5f3bfebce19b604a7259a241/html5/thumbnails/15.jpg)
Preliminary Design
Gate
Funnel
Funnel
![Page 16: Case Study: How to Avoid Failures in the Design and ......SustainTech –Saskatoon, SK March 21, 2019 Kevin French Case Study: How to Avoid Failures in the Design and Installation](https://reader034.vdocument.in/reader034/viewer/2022043020/5f3bfebce19b604a7259a241/html5/thumbnails/16.jpg)
Preliminary Design
![Page 17: Case Study: How to Avoid Failures in the Design and ......SustainTech –Saskatoon, SK March 21, 2019 Kevin French Case Study: How to Avoid Failures in the Design and Installation](https://reader034.vdocument.in/reader034/viewer/2022043020/5f3bfebce19b604a7259a241/html5/thumbnails/17.jpg)
Bench-Scale Testing
• The municipal client did not have
experience with ZVI PRB technology
• Bench-scale treatability testing was
offered to provide “proof-of-concept”
and assurances to client
• Samples of contaminated
groundwater obtained from the site
and mixed with ZVI and sand
![Page 18: Case Study: How to Avoid Failures in the Design and ......SustainTech –Saskatoon, SK March 21, 2019 Kevin French Case Study: How to Avoid Failures in the Design and Installation](https://reader034.vdocument.in/reader034/viewer/2022043020/5f3bfebce19b604a7259a241/html5/thumbnails/18.jpg)
Bench-Scale Testing
• Parameter-specific
degradation half-lives
calculated based on
bench-scale tests
• Compared to literature
references as a reality
check
• >95% reduction in
total CVOCs achieved
over 22 days of testing
![Page 19: Case Study: How to Avoid Failures in the Design and ......SustainTech –Saskatoon, SK March 21, 2019 Kevin French Case Study: How to Avoid Failures in the Design and Installation](https://reader034.vdocument.in/reader034/viewer/2022043020/5f3bfebce19b604a7259a241/html5/thumbnails/19.jpg)
Preliminary Design & Bench-Scale Testing
• Preliminary PRB design was determined using a computer model that
assessed:
– CVOC concentrations in groundwater and target treatment
concentrations
– Physical, geological and hydrogeological conditions of the soils at the
site and in the planned PRB
– CVOC half-lives from the bench-scale testing (first order decay)
– Groundwater temperature conditions for site
– Groundwater flux balance through “funnel & gate” PRB configuration
• In order to meet PSS levels using reported groundwater flow velocities a
PRB 1.0 m thick would need to contain 37% ZVI
![Page 20: Case Study: How to Avoid Failures in the Design and ......SustainTech –Saskatoon, SK March 21, 2019 Kevin French Case Study: How to Avoid Failures in the Design and Installation](https://reader034.vdocument.in/reader034/viewer/2022043020/5f3bfebce19b604a7259a241/html5/thumbnails/20.jpg)
Preliminary Design & Bench-Scale Testing
• Sensitivity analysis completed on
all input variables
• Model (and therefore results)
most sensitive to hydraulic
conductivity
• k-values varied by over 3 orders
of magnitude, other parameters
by <1
• Recommended additional site
characterization to reduce
uncertainty in predicted results
Value used in model
![Page 21: Case Study: How to Avoid Failures in the Design and ......SustainTech –Saskatoon, SK March 21, 2019 Kevin French Case Study: How to Avoid Failures in the Design and Installation](https://reader034.vdocument.in/reader034/viewer/2022043020/5f3bfebce19b604a7259a241/html5/thumbnails/21.jpg)
High-Resolution Site Characterization
![Page 22: Case Study: How to Avoid Failures in the Design and ......SustainTech –Saskatoon, SK March 21, 2019 Kevin French Case Study: How to Avoid Failures in the Design and Installation](https://reader034.vdocument.in/reader034/viewer/2022043020/5f3bfebce19b604a7259a241/html5/thumbnails/22.jpg)
High-Resolution Site Characterization
Hydraulic Profiling Tool (HPT)
• Direct-push
• Assess formation permeability
• Water injected into the ground; flow and
back-pressure measured
• EC: Estimate of soil type
• Identifies location of water table (no wells)
• Result: Empirical estimate of hydraulic
conductivity on a cm scale
• HPT deployed at the site to find preferential
flow paths in the saturated zone and to
define lower “confining layer”
![Page 23: Case Study: How to Avoid Failures in the Design and ......SustainTech –Saskatoon, SK March 21, 2019 Kevin French Case Study: How to Avoid Failures in the Design and Installation](https://reader034.vdocument.in/reader034/viewer/2022043020/5f3bfebce19b604a7259a241/html5/thumbnails/23.jpg)
High-Resolution Site Characterization
![Page 24: Case Study: How to Avoid Failures in the Design and ......SustainTech –Saskatoon, SK March 21, 2019 Kevin French Case Study: How to Avoid Failures in the Design and Installation](https://reader034.vdocument.in/reader034/viewer/2022043020/5f3bfebce19b604a7259a241/html5/thumbnails/24.jpg)
High-Resolution Site Characterization
![Page 25: Case Study: How to Avoid Failures in the Design and ......SustainTech –Saskatoon, SK March 21, 2019 Kevin French Case Study: How to Avoid Failures in the Design and Installation](https://reader034.vdocument.in/reader034/viewer/2022043020/5f3bfebce19b604a7259a241/html5/thumbnails/25.jpg)
High-Resolution Site Characterization
How to keep water from freezing in a 0.25” diameter line when the temperatures on-site are -10 to -20°C?
![Page 26: Case Study: How to Avoid Failures in the Design and ......SustainTech –Saskatoon, SK March 21, 2019 Kevin French Case Study: How to Avoid Failures in the Design and Installation](https://reader034.vdocument.in/reader034/viewer/2022043020/5f3bfebce19b604a7259a241/html5/thumbnails/26.jpg)
High-Resolution Site Characterization
![Page 27: Case Study: How to Avoid Failures in the Design and ......SustainTech –Saskatoon, SK March 21, 2019 Kevin French Case Study: How to Avoid Failures in the Design and Installation](https://reader034.vdocument.in/reader034/viewer/2022043020/5f3bfebce19b604a7259a241/html5/thumbnails/27.jpg)
High-Resolution Site Characterization
Unsaturated Zone
Higher K Zone
Lower K Zone
Confining Layer
![Page 28: Case Study: How to Avoid Failures in the Design and ......SustainTech –Saskatoon, SK March 21, 2019 Kevin French Case Study: How to Avoid Failures in the Design and Installation](https://reader034.vdocument.in/reader034/viewer/2022043020/5f3bfebce19b604a7259a241/html5/thumbnails/28.jpg)
Updated Final Design
![Page 29: Case Study: How to Avoid Failures in the Design and ......SustainTech –Saskatoon, SK March 21, 2019 Kevin French Case Study: How to Avoid Failures in the Design and Installation](https://reader034.vdocument.in/reader034/viewer/2022043020/5f3bfebce19b604a7259a241/html5/thumbnails/29.jpg)
Updated Final Design
• Data from the HPT testing activities was used to update the preliminary
design for the PRB:
• In order to meet PSS reduction using updated site data a PRB containing
30% ZVI would now only need to be 0.9 m thick (~27% savings)
![Page 30: Case Study: How to Avoid Failures in the Design and ......SustainTech –Saskatoon, SK March 21, 2019 Kevin French Case Study: How to Avoid Failures in the Design and Installation](https://reader034.vdocument.in/reader034/viewer/2022043020/5f3bfebce19b604a7259a241/html5/thumbnails/30.jpg)
Full-Scale Installation
![Page 31: Case Study: How to Avoid Failures in the Design and ......SustainTech –Saskatoon, SK March 21, 2019 Kevin French Case Study: How to Avoid Failures in the Design and Installation](https://reader034.vdocument.in/reader034/viewer/2022043020/5f3bfebce19b604a7259a241/html5/thumbnails/31.jpg)
Full-Scale Installation
• Cut and fill method PRB
• Concrete wing walls for “Funnels”
were 12 m long and 6 m long
• Cut / fill (using trench box) the
“Funnel” wing walls with concrete
• Excavate PRB “Gate” section using
biopolymer slurry (guar gum) for
sidewall support
• Coarse sand for PRB “Gate”
delivered in cement mixing truck;
ZVI added to truck and blended
![Page 32: Case Study: How to Avoid Failures in the Design and ......SustainTech –Saskatoon, SK March 21, 2019 Kevin French Case Study: How to Avoid Failures in the Design and Installation](https://reader034.vdocument.in/reader034/viewer/2022043020/5f3bfebce19b604a7259a241/html5/thumbnails/32.jpg)
Full-Scale Installation
• Backfill PRB “Gate” section with
ZVI / sand mixture and avoid
gravity separation through slurry
• Break slurry and pump back from
trench into on-site tank for off-site
disposal
• Place and compact granular trench
cap and repave
• Completed over 6 days on-site
![Page 33: Case Study: How to Avoid Failures in the Design and ......SustainTech –Saskatoon, SK March 21, 2019 Kevin French Case Study: How to Avoid Failures in the Design and Installation](https://reader034.vdocument.in/reader034/viewer/2022043020/5f3bfebce19b604a7259a241/html5/thumbnails/33.jpg)
Full-Scale Installation
![Page 34: Case Study: How to Avoid Failures in the Design and ......SustainTech –Saskatoon, SK March 21, 2019 Kevin French Case Study: How to Avoid Failures in the Design and Installation](https://reader034.vdocument.in/reader034/viewer/2022043020/5f3bfebce19b604a7259a241/html5/thumbnails/34.jpg)
Full-Scale Installation
![Page 35: Case Study: How to Avoid Failures in the Design and ......SustainTech –Saskatoon, SK March 21, 2019 Kevin French Case Study: How to Avoid Failures in the Design and Installation](https://reader034.vdocument.in/reader034/viewer/2022043020/5f3bfebce19b604a7259a241/html5/thumbnails/35.jpg)
Full-Scale Installation
![Page 36: Case Study: How to Avoid Failures in the Design and ......SustainTech –Saskatoon, SK March 21, 2019 Kevin French Case Study: How to Avoid Failures in the Design and Installation](https://reader034.vdocument.in/reader034/viewer/2022043020/5f3bfebce19b604a7259a241/html5/thumbnails/36.jpg)
Full-Scale Installation
![Page 37: Case Study: How to Avoid Failures in the Design and ......SustainTech –Saskatoon, SK March 21, 2019 Kevin French Case Study: How to Avoid Failures in the Design and Installation](https://reader034.vdocument.in/reader034/viewer/2022043020/5f3bfebce19b604a7259a241/html5/thumbnails/37.jpg)
Quality Assurance / Quality Control
![Page 38: Case Study: How to Avoid Failures in the Design and ......SustainTech –Saskatoon, SK March 21, 2019 Kevin French Case Study: How to Avoid Failures in the Design and Installation](https://reader034.vdocument.in/reader034/viewer/2022043020/5f3bfebce19b604a7259a241/html5/thumbnails/38.jpg)
Quality Assurance / Quality Control
• Samples of ZVI / sand mixture
collected from each batch and
subjected to magnetic separation
testing
• Post-installation boreholes drilled
through “Gate” portion of PRB and
subjected to magnetic separation
testing (similar results)
• One monitoring well drilled approx.
1.5 m downgradient of PRB for
groundwater sampling and analysisTarget ZVI Concentration = 30%
![Page 39: Case Study: How to Avoid Failures in the Design and ......SustainTech –Saskatoon, SK March 21, 2019 Kevin French Case Study: How to Avoid Failures in the Design and Installation](https://reader034.vdocument.in/reader034/viewer/2022043020/5f3bfebce19b604a7259a241/html5/thumbnails/39.jpg)
Performance Monitoring
![Page 40: Case Study: How to Avoid Failures in the Design and ......SustainTech –Saskatoon, SK March 21, 2019 Kevin French Case Study: How to Avoid Failures in the Design and Installation](https://reader034.vdocument.in/reader034/viewer/2022043020/5f3bfebce19b604a7259a241/html5/thumbnails/40.jpg)
Performance Monitoring
Groundwater
Flow Direction
![Page 41: Case Study: How to Avoid Failures in the Design and ......SustainTech –Saskatoon, SK March 21, 2019 Kevin French Case Study: How to Avoid Failures in the Design and Installation](https://reader034.vdocument.in/reader034/viewer/2022043020/5f3bfebce19b604a7259a241/html5/thumbnails/41.jpg)
Performance Monitoring
PSS for PCE PSS for TCE
![Page 42: Case Study: How to Avoid Failures in the Design and ......SustainTech –Saskatoon, SK March 21, 2019 Kevin French Case Study: How to Avoid Failures in the Design and Installation](https://reader034.vdocument.in/reader034/viewer/2022043020/5f3bfebce19b604a7259a241/html5/thumbnails/42.jpg)
Performance Monitoring
PSS for PCE PSS for TCE
![Page 43: Case Study: How to Avoid Failures in the Design and ......SustainTech –Saskatoon, SK March 21, 2019 Kevin French Case Study: How to Avoid Failures in the Design and Installation](https://reader034.vdocument.in/reader034/viewer/2022043020/5f3bfebce19b604a7259a241/html5/thumbnails/43.jpg)
Performance Monitoring
Generic
Standards
Met!PSS for PCE PSS for TCE
SCS for VC
SCS for PCE, TCE & DCE
![Page 44: Case Study: How to Avoid Failures in the Design and ......SustainTech –Saskatoon, SK March 21, 2019 Kevin French Case Study: How to Avoid Failures in the Design and Installation](https://reader034.vdocument.in/reader034/viewer/2022043020/5f3bfebce19b604a7259a241/html5/thumbnails/44.jpg)
Lessons Learned
![Page 45: Case Study: How to Avoid Failures in the Design and ......SustainTech –Saskatoon, SK March 21, 2019 Kevin French Case Study: How to Avoid Failures in the Design and Installation](https://reader034.vdocument.in/reader034/viewer/2022043020/5f3bfebce19b604a7259a241/html5/thumbnails/45.jpg)
Lessons Learned
• Review ESA data, develop CSM and preliminary
design (data gaps, sensitivity, etc.)
• Bench-scale testing for site-specific response
• Collect additional site data (HPT) to resolve
uncertainties (confining layer, k values)
• Ensure no gravity separation of ZVI / sand admixture
as it is emplaced
• Implement robust QA/QC programme during and post-
installation
• Ensure field installation is as per final design
![Page 46: Case Study: How to Avoid Failures in the Design and ......SustainTech –Saskatoon, SK March 21, 2019 Kevin French Case Study: How to Avoid Failures in the Design and Installation](https://reader034.vdocument.in/reader034/viewer/2022043020/5f3bfebce19b604a7259a241/html5/thumbnails/46.jpg)
Questions?
Thank You for
Your Time
Kevin FrenchVertex Environmental Inc.
(519) 653-8444 x 303
(519) 404-5442 mobile
www.vertexenvironmental.ca