Grundvattendagarna 2017

1. StopPFAS – In-situ remediation of
PFASs based on sorption methods
Fritjof Fagerlund – Uppsala University
Lutz Ahrens, Mattias Sörengård, Erik Östblom,
Dan Berggren Kleja – SLU
Jonny Bergman – RGS Nordic
Henning Persson – SGU
Marko Filipovic – NIRAS
Photo: Lorenzo Gambaro/Shutterstock

2. PFAS: Per- and Poly-Fluorinated
Alkyl Substances
PFOS
PFHxS
PFOA
PFHxA
• Fluorinated, hydrophobic tail – hydrophilic functional group
• More than 3000 different compounds
• Unique properties – found in numerous consumer products
• Widespread contamination – Ubiqitous in nature
Sulfonic acids Carboxylic acids

3. PFAS characteristics
• Common in fire-fighting Aqueous Film Forming Foam (AFFF)
• Suspeted negative health effects, PFOS banned
• Extremely persistent
• Bioaccumulate
• Food Agency’s limit: 90 ng/L => Problematic at low conc.
• C-F bond strongest in organic chemistry
• Very difficult to mineralize and remediate in-situ
Photo: RegenesisFoto: J-M Mayotte

4. StopPFAS – Concept
 Sorbents are applied in a
remediation zone
• Stops further migration of
PFASs
• PFASs are collected and
concentrated in a small
area
 The remediation zone is
regenerated
• More efficient than
cleaning very low conc.
from large volumes
• Different options will be
evaluated
PFAS plume
source
area
remediation zone
soil
grain
sorbent
PFAS

5. StopPFAS – Objectives
• Provide new knowledge on in-situ sorption of PFASs
• Develop methods for in-situ remediation of PFASs in
groundwater and soils
• Investigate the performance of a range of different sorbents for
PFASs in the laboratory
• Develop reactive transport modelling tools for design and
assessment of in-situ PFAS remediation
• Perform a pilot-scale PFAS immobilization experiment using
liquid activated carbon (PlumeStop®)
• Test electro-remediation for regeneration of soil-sorbent
mixtures loaded with PFASs.
• Develop practical guidelines for how to implement PFAS
remediation methods at field sites.

6. StopPFAS project structure
soil
grain
sorbent
PFAS
Sorbents
PFAS plume
source
area
remediation zone
Project managementSteering group
(all researchers)
Stakeholder &
advisory group
WP1 Laboratory
WP2 Modelling
WP3 Pilot test
WP4 Guideline

7. Sorption of PFASs
Photo: Mattias Sörengård
Sand Clay Peat
PAC GAC PlumeStop®
 Systematic testing of
sorbents in the
laboratory
 PFASs of different
type and length
 Different sorbents
 Different soils
 Focus on Swedish
conditions
 Preliminary results
from the PFAS
PURE project (PI
Lutz Ahrens)

8. Test of 50 sorbents and 20 PFASs
 Promising results for
Activated Carbon materials
 Log(Kd/(L/kg)) values of 3-5
for most PFASs
Mattias Sörengård, PhD candidate; Erik Östblom, MSc Thesis. PFAS PURE project (PA: Lutz Ahrens).

9. Sorption of PFASs to various materials
Mattias Sörengård, PhD candidate; Erik Östblom, MSc Thesis. PFAS PURE project (PA: Lutz Ahrens).
(L/kg)

10. Pilot test: Fire-fighting training site at
Hasslum, Skövde
• One of numerous hot
spot areas will be
chosen for pilot test
Photo: SGU WSP, Hasslum Slutrapport 2017-02-08

11. PlumeStop
• Liquid Activated Carbon
• Colloidal suspension 1 – 2 µm particles
• Includes dispersive polymers – mobile
and distributes in the subsurface
• Non-toxic
• Sorbs contaminants
• Attracts bio matrix – can enhance
biodegradation
Photo: Regenesis

12. PlumeStop SEM pictures
Clean sand grains
Grains coated with PlumeStop Microbial collonisation of surfaces
Picture: Regenesis
Picture: Regenesis
Pictures: Regenesis
 Surfaces are coated with micron-scale
activated carbon
 Large surface area for sorption
- Shown to sorb PFOS and PFOA
 Microbial collonisation
- Unclear if advantageous for PFASs
1
2
3

13. Thank You!
Photo: Lorenzo Gambaro/Shutterstock
The StopPFAS project receives
funding from: Tuffo – A research
and innovation program on
contaminated sites managed by
the Swedish Geotechnical
Institute (SGI).