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Achieving Remediation Success Using Good Science and Effective System Optimization Processes
April 2016
Chuck Whisman, PE – CH2MLydia Ross – CH2MChuck Blanchard, PE – CH2M
2
Agenda
Discuss RPO in regards to:
Definition and Overview
Site Strategy and Conceptual Site Model (CSM)
Visualization to Identify the Problem and Monitor Progress
Pilot Testing Pitfalls and Best Practices
System Design
Technology Specific Optimization
3
Remedial Process Optimization
What is RPO and how has it evolved?
Why implement optimization on a programmatic basis?
More sites in O&M phase.
High cost of operations.
Reserve accruals are significant.
Not meeting closure goals.
Improve likelihood for success for new and existing remediation projects.
Helps drive competency, risk reduction, and operational integrity management.
Integrates with sustainability drivers –more focus on social & economic impact assessment.
Original Definition (USAF, 2001):
RPO is a deliberate and systematicapproach to evaluate and improve site remediation processes while maximizing risk reduction for each dollar spent.
EPA - 2012“Efforts at any phase of the removal or remedial response to identify and implement specific actions that improve the effectiveness and cost-efficiency of that phase. Such actions may also improve the remedy’s protectiveness and long-term implementation which may facilitate progress towards site completion.”
4
Simplify the RPO Process
Complete Conceptual Site Model & Develop Site Strategy
Evaluate Applicable Remediation Technologies
Design, Install Operate the Most Appropriate System
Science to Guide the Assessment
• Know where mass is located and how much is present in soil/gw/NAPL.
• Understand site variability in geology and how that may effect remediation.
• Visualize the source area(s).
• Consider all potential site uses and remediation endpoints (including social & economical impacts).
Science to Guide the Assessment
• Perform in-field feasibility testing, when possible, to collect design data and information to compare potential technologies.
• Perform life-cycle remediation costs of all applicable technologies.
• Develop a system optimization plan with deign and operational goals that will help increase likelihood of reaching remediation endpoints.
Science to Guide the Design/O&M
• Design better wells, piping, and equipment , while allowing for more “flexibility” for adjustments. (High Efficiency and Easy to Optimize!)
• Incorporate optimization into O&M adjustments and data collection (Can the system perform optimization tasks automatically or allow for remote adjustments).
• Understand the value of high run-time and constant optimization adjustments.
You don’t want this process to be a cycle!
CLOSURE
5
Remediation Optimization
Typical project involves assessment, pilot testing, establishment of design parameters, design,
construction, and operation.
Remediation optimization generally involves optimizing mass recovery rates and ensuring that
actual ROI >= design ROI. Does operation match or exceed design expectations?
At most sites, if design parameters are achieved, the site will remediate in a reasonable time.
Issues occur when incorrect design parameters are selected or not achieved during operation
6
Examples of Optimization Approaches
Solutions Contracting
Independent Evaluation
“Fresh-eyes” review, brainstorming, shallow scope
Unit Process Optimization
Focused effort on known trouble spots in process units
Strategic Planning
Revisit the remedial strategy and/or regulatory objectives, regulator involvement
may be required
Smart O&M
Most efficient and cost-effective, on-going RPO with integrated team
Comprehensive Remedy Evaluation
Encompasses the RPO spectrum, most significant potential cost savings
7
RPO Focus Areas
Remedial
Process
Optimization
Remediation Strategy • Exit Strategy development
• Revisit cleanup levels
• Review risk assessment
• Life-cycle analysis
• Land use assumptions/controls
Monitoring Optimization• Reduced wells and frequency
• Reduced analytical
• Automation/telemetry
• Statistical tools for large sites
• Passive sampling methods
Alternative Technology• Aggressive source removal/reduction
• Innovative technologies
• Rely on natural processes
• Sustainable solutions
• Active to passive transition
Operation and Maintenance Review• Unit process optimization
• Alternate or modified treatment
• Automation/telemetry
• Energy efficiency and materials reduction
• Labor reduction
Design Optimization• Objectives and endpoints definition
• Hazard and Operability (HAZOP) study
• Value Engineering
• Constructability review
• Green remediation
Site Characterization• Accelerated site characterization (Triad)
• Conceptual site model (CSM) certainty
• Real-time measurements/monitoring
• Passive/no-purge samplers
• Multi-incremental sampling
• 3D visualization
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Sustainability Concepts & Optimization
Remediation decisions that look at social and economic impacts may also be able to positively impact RPO efforts.
Waste reduction and/or re-use.
Energy efficiency (inc. solar, wind, and battery powered solutions).
Re-use of remediation equipment (flexible design requirements) and re-purposing sea boxes.
Mass reduction vs. mass displacement (are we just putting impacts in the ground into the atmosphere?).
Compare system recovery/remediation rates vs. NSZD –switch when appropriate.
Minimizing remediation duration & cost will minimize carbon footprint (less site visits and energy use).
Newer land-farming concepts (enhanced with heat, oxygen, oxidants, …), especially in remote areas.
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Carbon Footprint Comparison – to put it in perspective
Carbon SourceEstimated
Tons CO2/year
Hummer –15,000 miles/yr
11
Prius –15,000 miles/yr
4
15 Hp motor – 90%full load
55
250 cfm catalyticoxidizer– 40% duty
47
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Optimization – Should Also Look at System Efficiency & Cost Savings Ideas
1,500 gpm Chromium VI
water treatment system -
Existing ion exchange
resin was very expensive,
so bench testing
performed to look at other
resins. >$1Mil saved
annually.
16MGD Pumping System
– system upgrades
resulted in more efficient
electricity use and reduced
air emissions.
11
Incorporating Asset Integrity Concepts into RPO
Business Process Modeling
Threat/Risk Identification
Regulatory Requirements
Critical Operating Parameters
Root Cause Analysis
Management of Change
Condition Assessment
Failure Analysis
Process Safety Management
Competency
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Optimization w/ Remedial Endpoints in Mind
Understanding when the technology has reached
“its end” (or the site has been remediated to the
“maximum extent practical”).
When will natural source zone depletion (NSZD)
make more sense?
Are different site-specific risk-based endpoints
acceptable based on changing conditions?
For NAPL sites, understand NAPL mobility analysis
and risk assessment tools.
Review current life-cycle remediation cost options.
Should additional sampling be performed prior to
system shutdown to verify source reduction.
“MacGyver” it!
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Site Management Process Optimization (SMPO)
Long-term planning tool for optimization of a portfolio of environmental sites
Optimization of existing remediation systems
Technical support logic for programming and planning
Systematic annual evaluation of site progress and management risk
Collaborative- and consensus-based project to ensure results that meet wide range, and sometimes competing, site management objectives
Establishes a “tool” that can and should be revisited on a regular basis to update the business plan for the portfolio
14
Multi-Site Optimization Example
Includes technical performance and site understanding uncertainty scores, input from risk inventory, and life-cycle costs
Low Certainty Score = Large Life Cycle Cost Delta = High Priority
Site Name
Technical
Perform
Certainty
Site CSM
Certainty
Overall
Site
Certainty
Estimated
Life Cycle
Cost Best Case
Worst
Case
Optimize
Activity
Priority 1
LF-20 83% 66% 73% $420,000 $420,000 $620,000 No
SS-122 100% 98% 99% $245,000 $245,000 $248,000 No
ST-123 64% 52% 59% $2,776,000 $2,776,000 $6,296,500 Yes
SS-124 89% 94% 91% $300,000 $300,000 $341,500 No
SS-125 68% 62% 65% $1,800,000 $1,800,000 $2,710,000 Yes
SS-130 88% 78% 81% $275,000 $275,000 $343,250 No
SS-139 98% 94% 95% $245,000 $245,000 $265,000 No
SS-215 88% 95% 91% $467,114 $467,114 $614,182 No
SS-216 91% 95% 93% $424,257 $424,257 $519,767 No
HYDRANT 63% 47% 57% $1,450,000 $1,450,000 $1,707,500 Yes
Total $8,678,371 $8,678,371 $14,058,699
NOTES:
Site is given priority if CSM Certainty < 70% OR deviation between Best Case and Worst Case is > 1.5.
LCC = life-cycle cost to complete
"Complete" is defined as a site-specific site management endpoint including long-term care LUCs or clean closure. Limit of 30 years.
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Development of a Site Strategic Plan – Incorporating RPO
Philosophy:
Look at the big picture and keep the endgame in mind
Re-evaluate as new key data are gathered or conditions change
Key Components
Site end use (and options for it); e.g. operating facility vs site currently owned by others
Potential risks (human and ecological) and liabilities
Corporate objectives, financial analysis used. Is site closure important or minimize annual spend
Regulatory program - requirements, opportunities, limitations, stakeholder engagement
Operating Facility
Redeveloped Facility
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Remediation Strategy Development
Conceptual Site Model (CSM)
Doesn’t need to be refined to begin with
Update as more information is obtained
Geology/hydrogeology/redox conditions
Contaminants, source, concentrations
Risk pathways
Remediation, management, and
RPO strategies
Start thinking about them early
Data Gaps
Adjust the plan to collect information
needed to minimize variables
Component of CSM – Cross-Section
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Site Investigation Tools for Petroleum Hydrocarbons – Tools to Match the Site and the Objectives
Process of Selecting the tools
Evaluate existing CSM (e.g.
geology/hydrogeology/LNAPL
saturation)
Identify regulatory and other drivers
Preliminary consideration of
remedial strategy
Identify data gaps
Select the tools to cost effective
achieve; likely a combination of tools
CSM Cartoon
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Site Visualization of CSM Information
MIP and LIF tools can allow
for low-cost assessment &
visualization of source
areas.
While it is preferred pre-
remediation, it can also be
performed during existing
remediation:
for sites that have been in
remediation for a long time, or
to compare to pre-remediation
data).
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Visualizing Source Areas to Aid in the Remediation & Optimization Process
LIF Resolution of CSM – Identified Deeper LNAPL
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TCE Discharge Location Identified – calculating concentration and mass COC flux
Determine optimum locations for remediation wells, trenches, and/or focus.
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Other Examples of Visuals and Cost Data
Determine the Degree of Hydraulic ControlCost Evaluations
5
500
1,000
2,000
4,000
8,000
12,000
16,000
20,000
Drawdown(feet)
BTEX
(μg/l)
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Typical 4-phase Distribution of NAPL
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NAPL Mobility Nomenclature
23
NAPL SaturatedNo NAPL
Re
sid
ual NAPL
present but cannot flow into wells
Mo
bile NAPL can flow into wells
Mig
rati
ng NAPL can
flow to new area
Sres
Recoverable
Increasing NAPL Saturation
Residual Saturation Range
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LNAPL Smear Zone Profile
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Laser-induced Fluorescence
Ultraviolet Optical Screening Tool (UVOST™)
Measures fluorescence of PAHs relative to a reference emitter (%RE)
Accepted technology for delineation of LNAPL in subsurface soil
Direct-push
Real-time
Site- and LNAPL-specific response
“Calibrate” against in-well petroleum samples or analytical results of soil samples
Can be performed pre, during, and post remediation
Advanced LIF: Ratio of wavelength response can be used to semi-quantitatively characterize variation in LNAPL quality
Type of fuel or fuel mixture
Degree of weatheringLIF Rig
Example LIF Data
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Site Investigation Tools for Petroleum Hydrocarbons –Variety of Tools and Approaches
Intact soil core –Pore fluid
saturations
LNAPL Mobility Analysis: lines
of evidence to evaluate if it can
move
Pore fluid saturations and other
parameters; calculations
Free product mobility lab testing:
(Water Drive and centrifuge)
Soil Core Preparation
NAPL Saturation in Sediment
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Identify Product Saturation Zones
Core Indexing and photography to target remediation depths
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Petroleum Source Identification Process
Advanced Petroleum IdentificationBiomarkers PAHs
Simulated Distillation
VPH/EPH ASTM D5739 PIANOStable
Isotopes
Basic Petroleum Identification (GC-FID)
Gasoline Diesel Oil Other
Site History
Products in Use Known Releases Age of Releases Suspected Source
Suspected Petroleum Release
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What Does Basic Identification of a Petroleum Product Look Like?
Regular Gasoline
30W Motor Oil
Crude Oil
JP-7
Diesel #2
Abundance vs. Time
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Visual Comparisons
A visual comparison of
chromatograms between the
original product or a reference
product can provide a good
estimation of the weathering
process.
This is an example of the
alteration of gasoline due to
evaporation only.
Chromatograms from Wigger and Torkelson
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Natural Source Zone Depletion (NSZD) – An Important Part of the CSM for LNAPL
NSZD is the term used to describe the natural processes of subsurface volatilization, dissolution, and biodegradation of petroleum in source zones
It is more significant than previously thought and results in measurable petroleum losses
33
Information Management for RPO
Save Costs
Obtain Better Data and Information (higher quality and volume)
Reduce Risks & NOVs (allows for preventative management)
Allows us to make better business decisions (both technical & business informatics)
Expedite compliance and regulatory reviews and approvals (internal/external)
Assist compliance, regulatory, engineering, ER, HSSE, and permitting teams -drives collaboration across client teams/companies/regulators
Automate work flow, alerts, and reports
Visualize and analyze trends and information
Drive efficiency in operations and compliance – can make everyone’s job easier
Make better optimization decisions!
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Automate data collection, tracking, validating, and reporting!
Remediation system data
Air and groundwater monitoring and
compliances data
Life-cycle waste
management/minimization
Compliance/site audits
Maintenance
Process data/remote sensors
HSSE data and monitoring
Asset data
Permit information
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General Workflow Overview:Maximizing Software Capabilities
Incoming information is automatically processed into report quality deliverables
Database
Field Data
Lab Reports
Electronic Forms
Remote Sensors
Maps
Charts
Tables
Models
36
Information Management Solutions Can …
Work with existing systems
Integrate historical information
Bridge different groups (RP/consultant/regulator)
Save costs while reducing risks
Improve daily operations and management
Provides important information at your fingertips to optimize
remediation system performance or adjust to changes/challenges.
37
Maintenance Management
12%
25%
25%
25%
13%
Paper Inspections
Preinspection Office Work
Field Inspection
Data Collection
Data Entry
Quality Control
1%
68%
19%
6%6%
Tablet Inspections
Confidential Client – Field Inspection Time Allocation
50% office work
50% field work
7% office work
93% field work
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Field Data Collection
Use any platform – computer, tablet, or
smartphone
Make live updates
View layers of data and visuals
Manage and evaluate assessment and
remediation data
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Reporting/KPI’s
Dashboards are a great
way to integrate your
strategic performance
measures with the data
collected from multiple
sources into an easily used
platform
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“Smart” SVE System for Automating System Optimization
Using Sensors/Meters & Automated
Valves
Flow rates from individual SVE wells
Applied vacuum on each SVE line
In-line PID cycles across each influent SVE
line for vapor concentration
Data Processing
Flow rate & concentration used to calculate
mass recovery rate from each SVE line
The PLC adjusts actuating valves to the
overall maximize mass recovery rate
As certain SVE wells are remediated, the
system reacts by constantly adjusting valves
for optimized performance
Vacuum Transducer
Flow Transducer
Actuating Valve
1 2
3
SVE Wells
In-line PID (for concentration)
SVEBlower
Process Controls(for adjustments)
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Remote System Control Screen Shots
Photos from Product Level Control,, 2016
AS/SVE ControlsDPVE System
Biosparge System AS/SVE System
42
Understanding a Site – Pre-Remediation
Hydrocarbon (HC) impacts at a former bulk storage terminal – focus on one large area of impact. Dissolved benzene reduction is the driver.
• Mass of COC estimated in soil: 12,450 lb.
• Mass of COC estimated as NAPL: 780 lb.
• Mass of COC estimated in groundwater: 608 lb.
Feasibility testing showed the following results from individual wells:
• HC mass recovery rates up to 32 lb/day during SVE only
• HC mass recovery rates up to 47 lb/day during AS/SVE
• HC mass recovery rates up to 59 lb/day during vacuum-enhanced SVE
• NAPL recovery rates up to 12 gpd via total fluids recovery and 24 gpd using vacuum-enhanced recovery (mix of weathered gasoline & diesel)
• Gas injection ROI of 15 feet at and average of 5 scfm for ozone design parameters
• SVE mass recovery data from 16 wells showed likely three different source areas.
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Learning From Remediation Failures & Successes?
It is helpful to understand COC mass distribution and estimate mass volume prior to technology screening.
Use of in-field feasibility testing can help compare technologies, prove the best design approach, and understand site variabilities.
Optimization and up-time are both critical – and should be considered during system design (inc. well network, pipe sizes, controls, equipment). Up-time not important if the system isn’t effective.
It doesn’t have to be a new technology.
Remediation is a contact sport.
Do we know COC mass in soil, groundwater, and NAPL?
Are all source areas known?
It works in a bench test, but what about the field?
What are the life-cycle costs of ALL my remediation options?
Are we collecting the correct field data during the assessment and feasibility testing?
How can I design the system to make optimization easier?
How not to choose a technology!
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Important Pilot Testing Evaluation Parameters
Technology Key Parameters to Understand in the Field
SVE Flow, vacuum, influence, groundwater level, mass recovery rate
DPE Flow (vapor/gw/NAPL), vacuum, influence, groundwater level, mass recovery rate
ISCO Oxidant demand, volume delivered, inject-ability , bio enhancement, benefits of gas delivery, ..
LNAPL Recovery Initial and target transmissivity, fingerprinting, NSZD, enhance recovery technologies, …
45
Pilot Test Pitfalls – Third Party Review of Major O&G Client Remediation System Designs
Site 1 - Long-term SVE pilot test was performed. Vapor recovery rate from well was
not quantified.
Site 2 - Red flags during AS/SVE pilot testing were ignored (highly variable vapor
flowrates from wells, highly variable mass recovery rates from well, extremely low
induced vacuums at observation wells).
System was installed anyway. Portions of vadose zone rapidly were remediated while other
areas were largely unremediated. Site will require an extremely long remediation far in
excess of estimated life-span.
Site 3 - Design of vapor abatement equipment based on pilot testing mass recovery
rates and not on estimated mass of impact at site. This nearly always leads to
oversizing the equipment and high utility costs toward the latter part of remediation.
Vapor abatement equipment only needs to be large enough to remediate site in a timely
manner (say 2-3 years) as initial hydrocarbon recovery rates tend to drop rapidly.
46
Pilot Test Best Practices
- Clearly Define Goals and Outline Data Collection Needs
Pre-write data sheets so field personnel can easily double-check they have
collected all requested data
- Staff pilot test with knowledgeable remediation engineer who can analyze data in field
real time and make adjustments to test operation and data collection (with approval from
client/regulator or within approved scope of work) to optimize pilot test
Extending a pilot test beyond planned operation to collect vital data based on site
response is negligible cost compared to remobilizing for a second test, or having
incomplete data for system design
Be mindful of measurement units on pilot test equipment
- Test multiple technologies, locations, and/or depths to understand fluctuations due to
variations in site cover and subsurface conditions.
- Do not let rules of thumb be predictive of results
If results are inconsistent or unfavorable, do not continue with system design.
47
Know Your Equipment
Dwyer Instruments, Inc. Installation and Operating Instructions
“SCFH” AIR
Pilot Test data is useless if the correct units of measurement are not recorded.
Check user manuals to be sure you don’t need to perform a conversion to achieve the listed unit
Double-check settings to be sure you are measuring (CFH/CFM, Pressure/vacuum, etc.)
Write down where the reading was collected to determine if it is pre/post dilution air, restrictions etc.
48
Selection of Key Design Parameters
Use of incorrect design parameters will frequently lead to poor
performance. Examples of some key design parameters for various
technologies are listed below.
Technology Key Parameter Supplemental parameter 1 Supplemental Parameter 2
SVE Soil vapor velocity in key zones
Initial Mass recovery rate Vacuum v. distance evaluation
DPE Dewatering req. in target zones
Same as SVE parameters Liquid recovery rate and optimum drawdown/efficiency
ISCO Mass to be treated Lifespan of selected oxidant Travel distance of selected oxidant in target zones, contact time, DO enhancement
LNAPL Recovery/Remediation
Initial and targettransmissivity
LNAPL and/or groundwater ROI, enhancement (SVE)
Changes in volume, transmissivity, viscosity, …
49
System Design Pitfalls - Third Party Review of Major O&G Client Remediation System Designs
Site A - Skimming system is being implemented at a site with a large amount of
gasoline NAPL and a remedial goal of 5 ppb of benzene.
It was decided to sequence the remediation and start with product skimming prior to
multiphase extraction.
Site cannot close until residual NAPL is removed hence all effort removing mobile
NAPL (only 30% of total) is wasted.
Site B - Mass of hydrocarbon at site estimated based on dissolved phase mass
X an unscientific fudge factor (not based on soil analytical in saturated zone or
even octanol-water portioning coefficients).
Mass of hydrocarbon was underestimated by easily a factor of 100 leading to
selection of temporary injection of oxygenated water for the remedial technology.
Limited mass destruction resulted in zero reduction in GW concentrations
50
System Design Pitfalls - Third Party Review of Major O&G Client Remediation System Designs
Site C - Length of remediation is frequently based on past experience and
not the best available science.
This number is then used to perform life-cycle cost analyses which are
used to pick the lowest cost remedial option.
This can lead to selection of incorrect technology when the actual length
of remediation exceeds the estimated length.
Site D - Lack of quantification of ROI or use of incorrect (but easy) metrics.
LNAPL skimmer ROIs based on rules of thumb, instead of recovery models, leading
to extremely long (10-20 years) remediation duration..
SVE ROIs based on vacuum vs. distance rather than soil vapor velocities (SVV).
51
Examples of Designing for Optimization
Remediation Wells – using continuous-wrap well screen for high efficiency pumping (inc. NAPL recovery), SVE, AS, …
System Piping – reduced headless for higher range of adjustments – for moving liquids or gases. May also install piping for alternate technologies, if needed, or access/clean-out sumps.
System Equipment – design for flexibility – higher flow rates, more drawdown, larger ROI, …
Multi-Technology Approach – simultaneous or phased (if needed)
Sustainability Features – from re-use to power considerations.
Remote Monitoring – for automated or remote adjustments of just better data collection w/ sensors.
52
Evaluation of Actual Performance Data
Design parameters are frequently based on short pilot tests or limited
scope.
Once system is operational, substantially more data becomes
available. So use it!
Performance data can be used to:
Reconfirm design parameters are applicable at entire site
Readjust system life span estimates (and expectations), if necessary
Make changes to the system (e.g. adding extraction wells or changing
vacuum blowers)
Last resort – move to alternate remedial technology. Some technologies
look like a good idea but simply don’t work in practice.
53
Understanding a Site – During Remediation
Hydrocarbon (HC) impacts at a former bulk storage terminal – focus on one large area of
impact. Dissolved benzene reduction is the driver.
• Initial mass of COC estimated in soil: 12,450 lb.
• Initial mass of COC estimated as NAPL: 780 lb.
• Initial mass of COC estimated in groundwater: 608 lb. (max dissolved benzene = 1,400 ppb)
System performance - using SVE with total fluids recovery:
• Year 1 mass recovery rates: Q1 (2,604 lb); Q2 (1,460 lb); Q3 (842 lb); Q4 (719 lb). Total = 5,625 (of 13,838 lb
estimated, so ~ 41% reduction in Year 1 and approx. 8,213 lb left not including bio);
• At end of Year 1:
• Max dissolved benzene = 280 ppb (80% reduction in max. concentration)
• Remediation system continues to operate (with less wells and more aggressively per well);
• MIP study and soil sampling will be conducted to evaluate remaining source areas;
• Risk assessment will be re-evaluated with updated information.
• Adding air sparging (piping/vaults added at time of installation)
or using short-term oxidation injection being considered.
54
SVE WellFlow Rate
(scfm)
Applied Vacuum
(inches of water)
Mass Recovery Rate (HC lb/day)
SVE-1 45 scfm 10 iw 21 lb/day
SVE-2 20 scfm 47 iw 32.0 lb/day
*SVE-3 79 scfm 2 iw <2.0 lb/day
*SVE-4 0.5 scfm 47 iw <2.0 lb/day
SVE-5 60 scfm 8 iw 45.0 lb/day
Optimizing Requires Analyzing System Data & “Reacting” to Improve Results
SVE-3: High flow rate with low vacuum and low HC mass recovery – could this signal a potential line break?
SVE-4: Low flow rate, high vacuum, and low HC mass recovery – could this signal that SVE lines contain water?
55
Strategy for Closure -RPO Dashboard Tool
At-a-glance performance
tracking tool to assess
progress made toward
performance milestones:
Achieve 90% run time efficiency
Achieve 75% reduction in in-well
LNAPL thickness and total COC
concentration
Meet interim COC reduction goals
of 50%, 75%, and 90% to
ultimately achieve site closure
approval
Facilitates efficient decision
making during O&M
Reviewed during routine RPO
meetings (quarterly to annual
meeting frequency)
56
Typical O&M Challenges
Excessive expense for small contaminant mass removal
Inefficient and slow remediation progress
Deficient strategic plan
High potential for discharge compliance violations
High potential for safety issues
Operator complacency
Lack of effective management systems
Customized Contracting
57
LNAPL Remediation Optimization
Understand clean-up goals up-front (and consider NAPL mobility/risk analyses
to drive site-specific goals).
Product skimming only may not be an effective interim or pretreatment option
for technologies such as SVE or DPE.
Skimming and other NAPL recovery options have their place if immobilizing a
NAPL plume followed by MNA is the selected remedy.
Where skimming is applicable, these systems can be optimized as follows:
Ensure that skimmers are set at the correct height.
Benchmark recoverability at key wells using transmissivity analysis.
Document changes in transmissivity and be prepared to shut down wells that meet target
transmissivity values
Understand the skimmer ROI and estimated recovery over time. Consider adding extraction
points where there is insufficient coverage or time to reach target transmissivity is excessive.
58
Remedial Optimization Options – LNAPL recovery
Adjust skimmer or pump intake elevations.
Evaluate changes in transmissivity. If wells meet target
transmissivity goals, shut them down at least temporarily.
Evaluate effective ROI and expected remediation rate. Compare
to actual performance.
Add recovery wells where required to meet remedial goals.
Add vacuum for enhanced recovery.
Add groundwater recovery to increase recovery rate. Again,
excessive drawdown is frequently not beneficial and should be
evaluated.
59
Changes in LNAPL Composition with Sparging
Significant changes in LNAPL composition have
been observed
TPH speciation
confirmed removal
of aromatic,
small carbon
number
compounds
(<C10), and BTEX0%
20%
40%
60%
80%
100%
AliphaticTPH
AromaticTPH
<10 C10 BTEX
Percent Reduction In Fractions
46
60
NSZD Measurements Are Useful for a Uses
Delineating subsurface NAPL
footprint
Monitoring natural attenuation
processes and estimating
contaminant destruction rates
Better understanding source
zone longevity
Benchmarking remedies
and establishing endpoints.
Rates of NSZD can be significant and often in the range of active remediation systems, especially
those that have been operating for a few years.
61
Justify Switching to MNA - Direct Biological Evidence to Support Transition to MNA
Persistent naphthalene concentrations downgradient of ISS zone
Stable isotope probing (SIP) used to provide direct evidence of anaerobic
naphthalene biodegradation
Baited BioTraps with 13C radio-labeled naphthalene
Deployed for 30, 60, and 90 days in various existing monitoring wells
Lab analysis of the 13C naphthalene and 13C content in the biomass and carbon dioxide
Evidence of biodegradation, mineralization, and biomass incorporation
SIP results used along with other lines-of-evidence including trends, mass
budgeting, and source control to justify monitoring only remedy
Pump and treat system demolished, TI waiver granted, MNA approved
From Microbial Insights, Inc.
62
Permeable Absorptive Barriers (PAB)
Concept/Objective
Stop migration of LNAPL by
having it absorb to a media
(optimize design)
Finite life - so couple with other
approaches (use best material)
Organoclay and other media
considered
Average Absorption (g NAPL/g reactive media)
Brazil OC 1.08
PM-199 1.37
Calgon GAC 0.674
63
PAB Bench Testing, Design, and Inspection
64
Chemical Injection Considerations
In Situ Technologies
In Situ Bioremediation
Enhanced Reductive Dechlorination
(ERD)
Aerobic bioremediation
Gas delivery (ozone or air sparging)
In Situ Chemical Oxidation (ISCO)
In Situ Chemical Reduction (ISCR)
Most Common Options
Vertical injection wells
Direct push probes
Angled borings
Horizontal wells
GOAL: CONTACT! CONTACT! CONTACT!
Direct Push Injections
Horizontal Well Installation
Well Injection
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Potential Challenges with Short-Term Chemical Injection
Potential “daylighting”
Chemical storage, mixing, and/or delivery
Injection volume
Even distribution in heterogeneous lithology
Penetration into low permeability soils
Access (under buildings or other structures)
Uncertain distribution in fractured bedrock
Compatibility/corrosion issues
Vendors who will always say yes
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Understanding Theoretical Oxidant Mass Required for Hydrocarbon Reduction
Oxidizing Species
Molecular Weight
(lb-mole)Electrons per
moleculemoles electrons
per pound
Pounds (lb) Oxidizer per lb
HCLb Oxidizer per
1,000 lb HCComments
Oxygen 32 4 0.1250 3.25 3,250 Remediates through bio not direct oxidation.
Ozone 48 6 0.1250 3.25 3,250 Does not inc. hydroxyl radicals or bio from oxygen.
Hydrogen Peroxide
34 2 0.0588 6.91 6,910 Does not inc. hydroxyl radicals or
bio from oxygen.
Percarbonate 314 6 0.0191 21.26 21,260
Permanganate 158 3 0.0190 21.40 21,400
Persulfate 238 2 0.0084 48.34 48,340Does not inc. bio -residual sulfate ion
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Tap Water Purity Considerations – when mixing for chemical/oxidant injection
Most chemicals used for injection (including
oxidation) are mixed with water (usually tap
water sources) prior to injection.
Tap water sources often have chlorine and other
compounds
Other water delivery equipment (trucks and hoses) or
water systems (fire suppression) could also introduce
other compounds.
Some compounds (chlorine) could potentially react
with oxidants or other compounds to form
trihalomethanes or chlorinated ethanes.
Tap water sources may be treated with carbon pre-
mixing to provide a clean water source for injection.
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Oxidant Purity Considerations
Sodium Persulfate (>99%) – could have low levels of ammonium salt (<0.05%), chlorine/chlorate (<0.01%), lead (<0.002%)
Hydrogen Peroxide (>99.99% peroxide + water) – TOC (<0.0015%), Nitrate/Phosphate/Sulfate (<0.000002)
Potassium Permanganate (>99%) - <0.02% chlorine/chlorate, <0.05% chromium, <0.05% sulfate; <0.002% arsenic, <0.005% lead, <0.01% cadmium, <0.005% other metals (nickel, selenium), <0.2% insoluble compounds.
Sodium Bicarbonate (>99%) - <0.0002% chloride. <0.0002% sulfur, < 0.00005% other heavy metals
Ferrous Sulfate (>98%) - <0.5% tin oxide; <0.006% arsenic, <0.006% lead, <0.006% chromium
- Only partial potential impurities are shown above. Purity information is available from chemical manufacturer spec sheets (which can vary based on material grade and decomposition).
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Ozone/Peroxide Applications
Benefits of Ozone/Peroxide injection:
Results in creation of hydroxyl radicals – in addition to ozone and peroxide.
Secondary benefit – enhanced bioremediation – including downgradient of
injection area (especially with oxygen-fed system).
Air sparging effects.
24/7 generation of ozone can make it much more cost effective than liquid
injection technologies. Large systems available (>50 lb/day ozone).
Passive ozone systems – low flow rate, low concentration, convert atmospheric air
Aggressive ozone systems – high flow rate, high concentrations, oxygen-fed
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Hydroxyl Radical Reaction Rates
Contaminant Oxidation Reaction
Rates Using Ozone/Peroxide
(relative to MTBE @ 1.00).
The higher the oxidation rate,
the easier it oxidizes with
ozone/peroxide.
Data shown from APTWater
treatability studies.
Aromatics:
m-dichlorobenzene 1.38
o-dichlorobenzene 1.56
p-dichlorobenzene 3.25
Nitrobenzene 2.50
Chlorobenzene 3.50
Styrene 3.75
Phenol 4.13
Naphthalene5.88
Biphenyl 6.25
o-cresol 6.88
p-cresol 7.50Aniline 9.38
VOCs:
PCE 1.25
TCE 1.81
1,4-Dioxane 1.94
1,2-DCE 2.38
Vinyl Chloride 7.50
Other Compounds:
Ethanol 1.38
Ethylene Glycol 1.50
Hydrazine 2.81
Dimethyl Sulfide 10.63
Gasoline Additives:
MTBE 1.00
TAME 1.00
Toluene 3.19
Xylene 4.19
Ethyl Benzene 4.69
Benzene 4.94
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General Lesson Learned with ISCO
Common problems
Calculating the amount of oxidant needed (oxidant demand needs to
be understood).
Going right to a short-tern ISCO strategy without looking at
alternatives (conventional or ozone).
Bench tests performed not field injection tests to verify ROI or mass
reduction (easy to show results in a jar).
Short-term injection expectations did not meet expectations.
Using science to understand the best oxidizer, injection strategy, and
right volume.
HSSE and compatibility understanding.
High volume injection needed but not designed or possible.
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Problem: Large Cost for Small Contaminant Mass Removal
Cause: Inefficient, over-sized, aged remediation system without
turndown or transition plan
Solution: Eliminate and/or downsize
components or transition to alternate
technology
Suggested Scope:
O&M review, alternative technology evaluation, and design optimization
Primary Optimization Goal:
Reduced unit cost for O&M
Customized Contracting
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Solution: Optimize Unit Processes
Large NAPL Recovery System, Washington
Multi-stage treatment process
~20 years of application of optimization practices during O&M
Modification to high-rate GAC backwash
Installation of a walnut shell filter pre-treatment
Installation of a real-time groundwater level monitoring system
Regular automation and programmable
logic controller (PLC) upgrades to reduce
labor force from 3 to 2 full-time operators
Use deep well for process water use
Life-cycle cost savings >$600,000
Customized Contracting
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Problem: Inconsistent O&M Results Across Multisite Portfolio
Cause: Ineffective O&M management systems
Solution: Establish standardized protocols and practices
Suggested Scope:
O&M management systems evaluation
Primary Optimization Goal:
Reduced O&M cost across O&M portfolio
Customized Contracting
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Solution: Establish Standardized Protocols and Practices
Multisite Program Portfolio
Standardized practices yield consistent results
Collaboratively developed with customer input and agreement
Consistent and timely maintenance practices
prevention over repair
Relevant and meaningful data collection and application
Develop client-specific measurement tools to track metrics and trends
To provide a snapshot for client, engineer and operator
Data-driven decision making increases performance
Improved efficiencies yield measurable cost savings
Important to identify and mitigate any “waste” in the process
Contracting
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Designing for Future Remedy Optimization
Subgrade remedy designed to allow for concurrent redevelopment
Fully valved, zoned, 1,200 scfm air sparging and soil vapor extraction (AS/SVE) system
AS/SVE with future sequenced bioremediation
Over 800,000 lbs of contaminants volatilized and aerobically biodegraded over 6 years
89% historical average runtime efficiency
Annual operation and maintenance (O&M)budget reduced 37%
Exiting volatilization phase and entering biodegradation-driven remediation phase on schedule
RPO program continues to proactively drive site toward closure
Site is now home to one of the highest grossing home improvement stores in the U.S.
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Pump and Treat (P&T) Optimization Early Exit Strategy (EES)
Re-evaluated existing aged remedy to find early exit with lower cost
Biosparging (BS) to increase mass transfer and biodegradation within the saturated and capillary fringe portions of the smear zone
Continue to operate bioventing (BV)
Operate LNAPL recovery and pumpand treat systems for only first yearof BV/BS operation
Benefits
Enhances mass removal
Shorten remediation by >10 yrs
14 yrs reduction in groundwater extraction and treatment timeframe
Life cycle cost savings >$7MM
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P&T Optimization –Optimized Exit Strategy (OES)
Re-evaluated existing aged remedy to find exit with lowest protective cost
Short-term pulsed operation of the LNAPL recovery and P&T systems
until a technical rationale for passive site remediation is agreed upon
Additional analyses include CO2 efflux monitoring and phased,
progressive duration extraction system rebound/stability assessments
Benefits
Consistent with historical optimization discussions
No Explanation of Significant Differences (ESD) required
11 years reduction in groundwater extraction and treatment timeframe
Life cycle cost savings >$8MM
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P&T System Unit Process Optimization
Multi-stage treatment process
Equalization, suspended solids and oil and grease removal, activated sludge, multimedia filtration, and granular activated carbon (GAC) polishing
~20 years of application of optimization practices during O&M:
Modification to high-rate GAC backwash to more aggressively remove solids and break up preferential flow pathways
Extended GAC life 2-3 months
Installation of a walnut shell filter pre-treatment
Installation of a real-time groundwater level monitoring system in individual extraction wells
Regular automation and programmable logiccontroller (PLC) upgrades to optimize controls and reduce labor force from 3 to 2 full-time operators
Use deep well for process water use
25 year life cycle cost savings >$600,000
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Horizontal Directionally-drilled (HDD) Remediation Wells
Significant advancement in HDD technology
Cost-effectively treats areas inaccessible to vertical wells
More efficient reagent/air delivery
CH2M HILL has installed over
30,000 feet of HDD wells
Groundwater extraction
Air sparging
Soil vapor extraction
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Remedial Optimization Options – SVE and DPE
The following are some options for optimizing SVE and DPE
systems going from minor to drastic
Shut down wells that are largely clean. Keep in mind that if you have a
blower or oxidizer that needs dilution air, it’s probably best to get it from the
ground and not the atm.
Cycle system operation if mass recovery is diffusion limited – reduces
overall cost and greenhouse emissions
Ensure that key target intervals are dewatered. If not on a DPE system,
you are just doing P&T
Add extraction points or add active venting to system (air injection into
vadose zone)
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Advances in Air Sparging/Soil Vapor Extraction (AS/SVE)
Air Injection
AS Wells
Vapor Treatment
SVE Wells
16
45
Long history of
application, finding
new life
Pulsed operation
common
Horizontal wells
Vapor Intrusion
Control
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• Accurate flowrate data is one of the most critical data points for system
design
• Frequently miscalculated or mislabeled by Consultants
• Multiple units are in use:
Standard cubic feet per minute (scfm) – volumetric flowrate at standard
conditions. Typically 14.7 psia but temp varies.
Actual cubic feet per minute (acfm) – flowrate at actual conditions. Temp
and press. must be specified.
Cubic feet per minute (cfm) – Used to define air compressor inlet flowrates
from the atmosphere and approximates scfm. Not used for scientific
discussion.
Inlet cubic flowrate (icfm) – Defines blower inlet flowrate at any pressure or
temperature. Again not used for scientific discussion.
Inaccurate Flowrate Data Examples
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Design Best Practice – Soil Vapor VelocitySVE ROI Determination Methods
Vacuum v. distance analysis is the most common but is typically insufficient for system design
Soil vapor velocity determination is a superior metric which allows quantification of remediation rate
SVE ROI has historically been determined by plotting vacuum vs. distance (a simple and easy method).
Commonly used because it is based on observable data.
Does not predict remediation rate.
Multiple metrics for determining the ROI leads to conflicting answers.
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Design Best Practice – Soil Vapor VelocityVacuum Versus Distance Example
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
10 100
Vac
uu
m (
in. w
.c.)
Distance from Extraction Well (ft)
Vac. V.Distance
Log. (Vac. V.Distance)
Vacuum Vs. Distance
1% of applied WHV (0.76 in. w.c.)22 foot ROI
0.1 in. w.c.48 foot ROI
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Design Best Practice – Soil Vapor VelocityFlux-Based SVE Evaluation
Subsurface vapor flow remediates sites, not vacuum.
Vacuum is responsible for generating flow
Quantification of soil vapor velocities (SVV) allows prediction of remediation rates.
Not a new concept. Pore volume exchanges (PVE) have long been identified as a metric for quantifying remediation rate.
SVV quantification allows PVE determination for soils not adjacent to the extraction well.
1,000 PV is a common design criteria for gasoline hydrocarbons
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Design Best Practice – Soil Vapor VelocitySVE ROI Determination
Knowledge of SVV and COC distribution allows for detailed cost
benefit analysis.
Calculation of remediation rates can be difficult even with SVV data
due to difficulties quantifying subsurface conditions.
In general, a 0.01 cm/sec SVV will result in a 2-year remediation of
most gasoline-range hydrocarbon plumes.
Simplified SVV calculations can be performed using only the vapor
extraction rate and the height of the unsaturated zone.
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Design Best Practice – Soil Vapor VelocityFlowlines to SVE Well
Travel time ticks at 1 day intervals
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Optimizing SVV
Boosting SVVs increases cost, but so does extended O&M.
Methods for increasing SVV and thus reducing O&M costs
include:
Increase number of extraction wells (reduced
spacing)
Increase wellhead vacuum (more hp, increased
blower expense, greater operating cost)
Reduce surface leakage (impermeable liner)
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Questions?
Remedial
Process
Optimization
Remediation Strategy
Monitoring Optimization
Alternative Technology
Remedial System Evaluation
Design OptimizationSystem Safety Analysis
O&M Management Systems
SolutionsCustomized Contracting
Sustainability Analysis
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Questions to discuss
Do your feel your projects are fully optimized? If not, what are they
missing?
Does it make sense to separate O&M contractor from RPO specialty
firm?
How can we provide effective oversight and field support in the
region?
Achieving Remediation Success Using Good Science and Effective System Optimization Processes
THANK YOU! April 2016
Chuck Whisman, PE – [email protected] Lydia Ross – [email protected] Blanchard, PE – [email protected]
