Free Product (LNAPL) in a Well Debunking the Alarmist Attitude/Stigma

Pertaining to Environmental Risk

Real Property Institute of Canada (RPIC) 2012 Federal Contaminated Sites National Workshop

Allstream Centre, Toronto, Ontario, Canada

Keynote Presentation by: David Cushman, Conestoga-Rovers & Associates

May 2, 2012

Debunking the stigma…

Quarter-Century (25-Year) Evaluation

  Evolution of LNAPL science   Regulatory approach - LNAPLs   Regulatory approach - Non-LNAPLs (i.e., all

other contaminants)

Free Product/LNAPL means:

  LNAPL - from right to left: •  NAPL – Non-Aqueous Phase Liquid (immiscible

in water; does not dissolve in water) •  L – Light (less dense than water; floats on water

in an open environment) •  May include pure solvents, but is mostly

recognized as oil or petroleum-related materials (fuels, lubricants, etc.)

…in a Well Means:

  LNAPL present in a monitoring or test well (also referred to as an observation well or piezometer)

  DOES NOT refer to LNAPL

present in a drinking water or potable water well

LNAPL

Water

Monitoring Well

Why the stigma?

  The thought of LNAPL (most often gasoline) in a well is simply “offensive”

  It’s explosive - gasoline in a well can lead to explosions or explosive conditions

  It’s toxic - one litre of gasoline can contaminate one million litres of water

  It can move - if it’s in a well, then it may move somewhere else and cause problems!

But…what would you do if…

  Most of what you believed about LNAPL (behaviour, dangers, risks) turned out to be false?

  Things that you thought were fact, were fiction?

  Perceptions that you had relied on for years turned out to be misperceptions?

Would you…

  Continue with the same old beliefs?   Continue along the same course?   Continue with the status quo?

Knowing that you’re wrong!

Yet that’s exactly what we do when we…   Automatically assume that LNAPL in a well

poses an unacceptable risk (to human health and/or the environment)

  Spend millions of dollars on unnecessary and unwarranted LNAPL cleanups

  Continue to ignore the current LNAPL science and forge ahead with the status quo!

Why is this important?

  Because LNAPL is one of the most prevalent, widespread, common pollutants on the planet •  Transportation (planes, trains, autos, ships) •  Heating and cooling •  Manufacturing (hydraulics, lubricants, fuel) •  Construction (hydraulics, lubricants) •  Etc.

Why is this important?

  Because billions of $$$ are spent on LNAPL investigations and remedial operations in North America alone

  Because many LNAPL remedial programs

generate more pollution and risk than what’s being mitigated

Why is this important?

  Because LNAPL remediation programs often prevent/preclude the beneficial redevelopment or re-use of real property

  Because the “perception” of significant risk is most often WRONG!

LNAPL misperceptions…

  LNAPL research and science over the past 25 years have taught us that most of what we thought we knew about LNAPL, is incorrect!

  For example…

We believed that…

  LNAPL floats on top of the water table and cannot penetrate into the water

FALSE!   At most sites, the majority of LNAPL is

located beneath the water table!

LNAPL beneath water table…

We believed that…

  LNAPL continues to migrate once at the water table, similar to groundwater migration

FALSE!   LNAPL bodies are spatially self-limiting, and

stop migrating shortly after the release is terminated!

We believed that…

  No LNAPL in wells means no LNAPL at the Site

FALSE!   Often times, LNAPL will be at a site and not

show up in wells!

We believed that…

  LNAPL disappearing from a well for an extended period of time (years) and then reappearing indicates a new release

FALSE!   Submerged LNAPL can remain in the

formation adjacent to a well for years, without appearing in the well!

We believed that…

  Decreases in in-well LNAPL thicknesses during active remediation mean that the remedial program is working

FALSE!   In-well LNAPL thickness may increase or

decrease in response to a fluctuating water table (with no connection to remedial progress)

In-well LNAPL thickness

changing in response to water table fluctuations

LNAPL

LNAPL

Normal Water Table

High Water Table

LNAPL

Low Water Table

LNAPL and Water Drainage

We believed that…

  With the proper technologies, all LNAPL can be hydraulically recovered from the subsurface

FALSE!   On average, no more than 50% of LNAPL

can be recovered (no more than 15% in finer soils)

We believed that…

  All LNAPLs result in extensive groundwater contamination

FALSE!   Middle distillate and heavier LNAPLs (diesel,

fuel oil, lube oil) seldom result in significant dissolved phase impacts

We believed that…

  Hydraulic recovery (pumping or skimming) of LNAPL from the subsurface results in groundwater concentrations being remediated

FALSE!   Hydraulic recovery of LNAPL has little to no

effect on dissolved phase concentrations!

Knowing what we now know, why do we refuse to change…

  Creatures of habit – resistant to change?   Don’t believe the science?   Don’t trust the science?   Don’t understand the science?   Blame it on the existing LNAPL laws/regs

(i.e., science has advanced, laws and regulations haven’t)!

Increasing Time (Years)

Evol

utio

n of

Kno

wle

dge

Science

Regs

1987

Regs

Science

Gap

Capillary Pressure Pore Entry Disp. Pressure

Multi-Phase Fluid Flow

Van Genuchten Parameters Saturation/Residual Saturation

Mobility/Stability

Relative Permeability

Transmissivity

From the “LNAPL” beginning…   Mid 1980s - retail petroleum facilities were in

a serious state of disrepair across Canada and the U.S.

  Estimates indicated that as many as 1/3 of underground storage tank (UST) systems (tank and associated piping) were leaking

  Numerous retail petroleum facilities with gasoline-impacted soil and groundwater

From the beginning…   Existing UST systems continued to corrode

and deteriorate, leading to additional releases to the environment

  Impacts were deemed to present a significant risk to human health and the environment

  Some impacts required emergency measures due to severity of risks (i.e., potential explosive situations)

Government response (U.S.)…

  Comprehensive federal UST regulations governing UST construction, operation, monitoring and release detection requirements

  40 CFR 280 - Technical Standards and Corrective Action Requirements for Owners and Operators of Underground Storage Tanks

Government response (U.S.)…

  40CFR280 requirements: •  §280.43 Methods of release detection for tanks

—  §280.43(f) Ground-water monitoring —  §280.43(f)(6) The continuous monitoring device or

manual methods can detect the presence of at least one-eighth of an inch of free product on top of the ground water in the monitoring wells;

“One-eighth of an inch”

Government response…

  40CFR280 requirements (Continued): •  §280.64 Free product removal

— At sites where investigations under §280.62(a)(6) indicate the presence of free product, owners and operators must remove free product to the maximum extent practicable as determined by the implementing agency while continuing, as necessary, … [underline/bold added].

“Maximum Extent Practicable (MEP)”

These two requirements…

  ⅛-inch free product (in well)   Remove free product to maximum extent

practicable (MEP)

Have been the source of much LNAPL debate for the past 25 years!

Why the debate…

  Regulators essentially “connected” the two requirements, and made the assumption that ⅛-inch = MEP

LNAPL in Well = Unacceptable Risk = Corrective Action

Evolving environmental times for non-LNAPL impacts…

  1980s – clean to background concentrations   1990s – added risk-based decision-making to

environmental cleanups (Risk-Based Corrective Action or RBCA)

  2000s – RBCA with sustainability considerations

Sustainability…   Considers risks to human health and the

environment, as well as balance between environmental, economic and social issues/performance

  More than “Green”, which just considers environmental benefit after remedy selection

  Does the proposed remedial action result in a net benefit, or detriment?

Sustainable performance…

Social Environmental

Economic Sustainable Performance

(balance between all three)

LNAPL in Well…Must Recover/Remediate

Remediate to Background

Concentrations

Risk-Based Corrective Action

(RBCA)

RBCA with Sustainability Considerations

Active Remediation

Monitored Natural Attenuation

(MNA)

1980s

1990s

2000s

LNAPL in A Well?

No Yes

Timeline

Due to the “perceived” threat, LNAPL in a well means that…

  Good science is ignored   Risk-based evaluations are ignored   Sustainability considerations are ignored   Costs are ignored

Proceed directly to recovery!

“Interpretation” of existing regs fails to recognize that…   All LNAPLs are different (chemical and

physical properties)   LNAPL chemical/physical properties,

geologic setting and land use dictate true risks   LNAPL chemical/physical properties and

geologic setting dictate migration potential

Carbon Chain Hydrocarbon Ranges for Various LNAPLs

C1 C4 C8 C12 C16 C20 C24 C28 <C30

Gasoline (C4 – C12)

Kerosene / Jet Fuel (C6 – C18)

Diesel / No. 2 (C8 – C21)

Lube Oil (C18 – >C34)

Crude Oil (C1 – >C34)

Gases Liquids Solids @20ºC

Hydraulic Oil (C18 – C30)

LNAPLs are not created equal   Light-end LNAPLs pose higher risk/toxicity

than heavier ends   Light-ends more soluble than heavy ends   Light-ends more volatile than heavy ends   Light-ends more combustible than heavy ends

Yet, even light-ends pose less risk than originally anticipated!

Unfortunately, many regulators continue with the belief that…

  All LNAPLs are equal   The mere presence of LNAPL represents an

unacceptable risk requiring active recovery   The absence of LNAPL in wells means the

site is clean!

As a result…

  Millions of $$$ are spent on unnecessary LNAPL remediation programs

  Non-sustainable LNAPL remediation practices continue to be the norm

  Some high-risk sites are closed based on the absence of LNAPL in wells!

Real life non-sustainable LNAPL examples…   $6.3M capital cost, $1M annual O&M   After 1.5 years:

•  40 million gallons of groundwater extracted •  750,000 kWh of power consumed

— Enough to power 65 average size homes for a year! •  300 gallons LNAPL recovered

— >$25K/gallon LNAPL

WHY?

Real life non-sustainable LNAPL examples…   $2.2M spent   1,655,050 kWh power consumed

•  Enough to power 140 average size homes for a year!

  Over 2 million pounds of CO2 emissions •  Thermal oxidizer, not including power generation

  3,000 gallons of LNAPL recovered

WHY?

Real life non-sustainable LNAPL examples…   Diesel-powered generator to run remediation

system   4,000 gallons of diesel generator fuel

consumed per month   Less than 50 gallons of diesel LNAPL

recovered per month

WHY?

Real life non-sustainable LNAPL examples…   Extracted gasoline LNAPL from 10 metres

below ground and dispersed untreated gasoline vapours into residential neighbourhood

ARE WE REALLY CREATING A NET BENEFIT?

How do we fix it?   It’s not the law/regulation itself, but rather the

“interpretation” of the law/regulation that needs to change

  In-well LNAPL thickness should never be used as a trigger to start/stop remediation

  Risk-based evaluations and sustainability considerations must be incorporated into the remedial decision-making process

How do we fix it?   We must build technically sound LNAPL

Conceptual Site Models (LCSMs) and use the LCSM information as a basis for remedial decision-making (see ITRC TechReg, December 2009)

  Maximum Extent Practicable (MEP) must be tied to the LCSM (including risk and sustainability considerations) – not in-well thickness

Where do we go from here…   Must first educate ENVIRONMENTAL

CONSULTANTS on current LNAPL science/guidance

  Next, educate/inform policymakers, regulators and the public in general about the gap between LNAPL science and regulations and the need to “adjust”

Where do we go from here…   Continue to learn, develop, and promote

sustainable LNAPL management and remediation practices that provide a net benefit to all!

Eventually…good science prevails!

THANK YOU!