Case
Studies
Tetra Tech has over 50 years’
experience conducting
site investigations and
remediation for a broad
range of contaminants.
PFAS, an emerging
contaminant with many
unique properties, requires
an experienced contractor
with a strong environmental
foundation and the ability
to innovate. The highlighted
case studies illustrate non-
routine site characterization
and innovative treatment
solutions for PFAS.
Treatment of PFAS from
Storm Water Basin
Tetra Tech designed and constructed
a 50 gallons per minute (gpm) PFAS
treatment system to address PFAS-
contaminated water that accumulates
in the tank berms from precipitation.
Tetra Tech conducted treatability studies
to determine the eicacy of removal of
PFAS associated with colloidal particles.
The innovative, state of the art mobile
treatment system is operating in a
renery combustion safety zone setting
and successfully treating a complex mix
of petroleum and PFAS constituents.
PFAS Treatment in
Seeps & Streams
Tetra Tech has completed several
tasks to mitigate migration of
PFAS o-site via surface water. At
one outfall, Tetra Tech designed,
constructed, installed, and
operated a one gallon per minute
SeepSorber
TM
system to remove
high concentrations of PFAS in seep
water. The seep water ows through
a treatment system containing PFAS
adsorbents. The system is currently
operating and has reduced PFAS
concentrations in the eluent seep
water by more than 99.99%.
Destruction of PFAS in Soil/
Sediments using Electron
Beam Technology
Tetra Tech has been collaborating
with Texas A&M University on
the research, development, and
commercialization of Electron
Beam (eBeam) technology for
the destruction of PFAS in soil,
sediments, biosolids, leachate,
and high concentration liquids.
The development of a eld
deployable system is underway
with support from SERDP-ESTCP
and other entities.
PFAS Treatability/
Pilot Tests
Tetra Tech has designed, constructed,
and operated a multi-column
treatability/pilot testing system for
the treatment of PFAS from two
waste streams. The treatability
tests were conducted in response
to PFAS concentrations detected in
the eluent from the WWTP and the
FFTA groundwater. The treatability/
pilot testing system consisted of four
parallel treatment trains to compare
four dierent treatment media for
PFAS removal. The results indicated
successful removal of multiple PFAS
with dierent breakthrough bed
volumes for each PFAS compound.
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Biota Sampling for PFAS
Risk Assessments
Tetra Tech collected shellsh (clams,
mussels) and n sh (brook trout,
black crappie) for PFAS analysis in
tissue to support human health and
ecological risk assessments at a DoD
site. The sample design included co-
located sediment and shellsh samples
to assess PFAS uptake. Samplers
followed Tetra Tech-developed SOPs
to avoid cross contamination of these
ubiquitous chemicals. EPA’s Method
1633 was used for tissue analysis of up
to 40 PFAS.
