FUEL FLUORESCENCE DETECTOR

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FUEL FLUORESCENCE DETECTOR FOR IN SITU
CHARACTERIZATION
May 22, 2008 Robert Wilson Vertek
Products Applied Research Associates 415 Waterman
Rd. S. Royalton, VT 05068
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FEATURES OF THE FFD

• Designed for direct push (CPT) deployment
• Real-time contaminant profiling vs. depth
  below ground
• Low cost alternative to LIF, UVOST, ROST
• Detects light and heavy fuels - gasoline,
  diesel, jet fuel,
• heating oil, crude oil, creosote, coal tar,
  and more
• Screen to low ppm concentrations in soil

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WHAT IS FLUORESCENCE?
Light emitted when an excited molecule
relaxes back to its ground energy state.
Excited
Exc.
Em.
Em.
Ex.
Energy
Excitation Intensity
Emission Intensity
Ground
Wavelength
Energy
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FFD PROBE OPTICAL LAYOUT
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MAJOR FLUOROPHORES IN FUELS ARE AROMATIC
HYDROCARBONS
Fluorescence Em. at 254nm Ex.
Key Aromatics Benzene Toluene Ethyl
Benzene Xylenes Naphthalenes PAH
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FLUORESCENCE EMISSION SPECTRA OF FUELS
Unleaded Gas
Excitation at 254nm
Diesel
Coal Tar
Fluorescence Intensity
Wavelength (nm)
Detection at a single wavelength will not suffice
for all fuels!
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FLUORESCENT POLLUTANTS
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FFD FILTERS COVER FUEL RANGE
Gas,Jet
Creosote
HFFD
Transmittance
LFFD
Wavelength (nm)
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CONE PENETROMETER FFD PROBE
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COMPLETE CPT FFD SYSTEM
FFD Controller
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THE CONE PENETROMETER FOR SITE CHARACTERIZATION
Sensors
Contaminant Plume
ARAs Cone Penetrometer Truck
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LFFD AT A JET FUEL SITE - 1998
CONTAMINATED
CLEAN
Thermal Induced Drift Region
Elevation (ft)
Baseline Drift
Water Table
Jet Fuel
Water Table
FFD Response (V)
FFD Response (V)
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LFFD FIELD INVESTGATION - 1996
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NAPL?
NAPL?
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FFD RESPONSE TO CREOSOTE
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DUAL WAVELENGTH FFD DATA FROM TWO SITES IN NY
STATE
Creosote
Gasoline
Response to heavy PAH
Smear zone above the water table
Response to light aromatics
Water Table
Volts
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VIDEOCONE CPT PROBE
Provides a continuous view of the subsurface
vs. depth using the same housing and window
as the FFD Unequivocally confirms the
presence of free phase product (Non-Aqueous
Phase Liquids - NAPLs) Works even with
colorless NAPLs (e.g., clean solvents) Easily
locates the water table and strata with high
pore water content White light source and
true color camera with high resolution (lt 10
µm) aids in soil classification
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VIDEOCONE SYSTEM
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VIDEOCONE OPTICAL LAYOUT
Color CCD Camera
Optics
Sapphire Window
Mirror
Lamp
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VIDEOCONE CONFIRMS FFD RESULTS AT A FORMER NY MGP
SITE
LFFD
HFFD
Creosote globules, some smaller than 1mm, are
easily viewed at a depth where the FFD gave a
strong response
Depth (ft)
10 mm
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VIDEOCONE IMAGE OF GASOLINE IN DARK SOIL AT NJ
SITE
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NAPLs OBSERVED TO DATE
Trichloroethylene (DNAPL) Perchloroethylene
(DNAPL) Carbon tetrachloride (DNAPL)
o-Nitrotoluene (LNAPL) Nitroglycerine
(DNAPL) Gasoline (LNAPL) Creosote (DNAPL)
Coal Tar (DNAPL)