.

1. Retrofitting a Drinking Water Well Site with
Ion Exchange Vessels for PFAS Removal
Rachel Burger, Lauren Todd, Shirin Udwadia,
Sophia Della Rocca, & Caroline Packard
CLEMSON UNIVERSITY, CLEMSON, SC
October 28, 2021

2. OUTLINE
● Introduction
○ Background
○ Rationale
○ Objectives
○ Approaches/Tasks
○ Deliverables
● Literature Review
● Materials and Methods
● Results
● Recommendations
● Acknowledgements

3. Introduction

4. Background
● Water fuels every aspect of life on earth.
○ Essential for basic human health and hygiene, and it drives society’s most essential
industries.
● Climate change due to human impact has created shorter rainy seasons and longer dry seasons,
diminishing many of the world’s water sources.
● Other than environmental changes affecting our water, pollution is a main threat.
○ Agriculture, industrial activities, and naturally occuring substances are all causes of water
pollution.
○ One contaminant polluting our water supplies is polyfluorinated substances (PFAS), which
are a category of synthetic chemicals used to make fluoropolymer coatings and products
that resist heat, oil, stains, and water.

5. Background
● PFAS substances have properties which make them water resistant as well as water soluble, allowing them to
bioaccumulate in bodies of water, and in human and animal populations.
● Due to the toxic nature of PFAS, and the fact that PFAS contamination is not federally regulated, the health of
humans and the environment has been negatively affected.
● Safe Drinking Water Act (SDWA) sets enforceable Maximum Contaminant Levels (MCLs) for specific chemicals
and can require monitoring of public water supplies
○ There are no current MCLs established for PFAS chemicals
○ EPA has initiated the steps to evaluate the need for a PFAS MCL
○ EPA has issued a health advisory for PFOA and PFOS
■ Informal guideline, non-regulatory
● The State Water Resources Control Board (SWRCB) of Orange County, California has set some of the most
stringent PFAS advisories in the country.

6. Rationale
● Since PFAS substances can dissolve in water, they travel through water
treatment facilities and small-scale water filters. However, they are not easily
detected or removed by traditional water treatment methods.
● PFAS substances pose a threat to public health and are heavily present in
drinking water sources.
○ Large amounts of PFAS have resulted in decreased performance of the
thyroid, immune system, liver, and reproductive system.
○ From the “Road of Death” case study in Australia, there was sufficient
evidence that higher levels of PFOS and PFOA in a person’s blood can
lead to a decline in health.

7. Rationale
● Therefore, efficient technology needs to be developed to provide safe
drinking water and mitigate the risk of PFAS exposure to public
health.
● Unconventional methods that are proven to be effective in removing
PFAS include activated carbon absorption, ion exchange resin, and
high pressure membrane filtration.

8. Objective
The objective of this project is to retrofit a drinking water well site with ion
exchange vessels as a treatment technology system for the purpose of
removing polyfluorinated substances (PFAS) and decontaminating the
community water systems.

9. Tasks
Task 1: To research PFAS and establish their general structure, usage, interaction in the environment, human health effects, and current federal and
state regulations.
Task 2: To study ion exchange vessels and define the mechanisms required for the removal process, and assess advantages and disadvantages
over other treatment processes.
Task 3: To determine and compare different vendors and technologies for the ion exchange vessel.
Task 4: To identify the specific characteristics of PFAS and contamination levels at the well site, in addition to water qualities such as pH, inorganic
ion and natural organic matter concentrations.
Task 5: To retrofit the drinking water treatment and distribution systems: wells, existing and additional pumps, engineering and design of novel
treatment technology.
Task 6: To create a model of the drinking water treatment system and site, and model PFAS removal.
Task 7: To estimate a budget for the cost of retrofitting the drinking water treatment and distribution systems (wells, existing and additional pumps,
and ion exchange filtration system).
Task 8: To assess the environmental, economic, and societal impacts of the ion exchange vessel on PFAS removal.
Data/
Analysis
Design/Modeling
Cost/
Recommendations

10. Tasks
Task 1 Task 2 Task 3 Task 4 Task 5 Task 6 Task 7 Task 8
Data/Analysis Design/Modeling Cost/Recommendations
Task 1: To research PFAS and establish their general structure, usage, interaction with the environment,
human health effects, and current federal and state regulations.

11. Tasks
Task 1 Task 2 Task 3 Task 4 Task 5 Task 6 Task 7 Task 8
Data/Analysis Design/Modeling Cost/Recommendations
Task 2: To study ion exchange vessels and define the mechanisms required for the removal process, and
assess advantages and disadvantages over other treatment processes.
● Sub-task 2.1: To research other proposed alternatives and compare them to the ion exchange
method.
● Sub-task 2.2: To identify any restrictions or limitations that need to be considered prior to
choosing a resin media and designing the vessels.

12. Tasks
Task 1 Task 2 Task 3 Task 4 Task 5 Task 6 Task 7 Task 8
Data/Analysis Design/Modeling Cost/Recommendations
Task 3: To determine and compare different vendors and technologies for the ion exchange vessel.

13. Tasks
Task 1 Task 2 Task 3 Task 4 Task 5 Task 6 Task 7 Task 8
Data/Analysis Design/Modeling Cost/Recommendations
Task 4: To identify the specific characteristics of PFAS and contamination levels at the well site, in
addition to water qualities such as pH, inorganic ions and natural organic matter concentrations.
● Sub-task 4.1: To select an anion exchange resin that is compatible with the PFAS and water
characteristics and maintains an adequate uptake capacity.
● Sub-task 4.2: To find a vendor with the selected anion exchange resin(s).

14. Tasks
Task 1 Task 2 Task 3 Task 4 Task 5 Task 6 Task 7 Task 8
Data/Analysis Design/Modeling Cost/Recommendations
Task 5: To retrofit the drinking water treatment and distribution systems: wells, existing and additional pumps,
engineering and design of novel treatment technology.
● Sub-task 5.1: To report the well’s original design, existing pumps, and flow characteristics, such as flow
rate, variability, and pressure.
● Sub-task 5.2: To analyze flow characteristics and determine if an additional pump or modification is
needed.
● Sub-task 5.3: To design a pre-filtration unit to remove large suspended solids and prevent damage to
following units and pipes.
● Sub-task 5.4: To develop a list of materials and equipment required for the design, and provide
calculations for design feasibility.

15. Tasks
Task 1 Task 2 Task 3 Task 4 Task 5 Task 6 Task 7 Task 8
Data/Analysis Design/Modeling Cost/Recommendations
Task 6: To create a model of the drinking water treatment system and site, and model PFAS removal.
● Sub-task 6.1: To design the well site using AutoCAD.
● Sub-task 6.2: To design the drinking water distribution and treatment using SuperPro.
● Sub-task 6.3: To model removal of PFAS using STELLA.

16. Tasks
Task 1 Task 2 Task 3 Task 4 Task 5 Task 6 Task 7 Task 8
Data/Analysis Design/Modeling Cost/Recommendations
Task 7: To estimate a budget for the cost of retrofitting the drinking water treatment and distribution
systems (wells, existing and additional pumps, and ion exchange filtration system).

17. Tasks
Task 1 Task 2 Task 3 Task 4 Task 5 Task 6 Task 7 Task 8
Data/Analysis Design/Modeling Cost/Recommendations
Task 8: To assess the environmental, economic, and societal impacts of the ion exchange vessel on
PFAS
removal.
● Sub-task 8.1: To evaluate the required maintenance, such as resin regeneration protocols, brine
treatment and reuse.
● Sub-task 8.2: To determine future impacts on the environment and human health.

19. Deliverables
Deliverable 1: Alternative technologies and vendors analysis
Deliverable 2: Models, designs, and calculations for the water treatment and distribution system components
Deliverable 3: Model for an effective yet aesthetically pleasing well site
Deliverable 4: Project budget
Deliverable 5: Develop recommendations for future maintenance, upkeep, and potential future challenges (water
quality, regulations, emerging contaminants)
Deliverable 6: Final report

20. Literature Review

21. What is PFAS?
● Perfluorinated/polyfluorinated substances (PFAS): group of man-made chemicals, used in
consumer products to make them non-stick and water resistant.
● PFAS are persistent chemicals and can bioaccumulate in bodies of water and of animals;
they can also dissolve in water and traditional drinking water treatment technologies
cannot remove them.
○ They have been aptly nicknamed “forever chemicals”.
● These chemicals have unique physical and chemical properties which allow them to repel
oil and water, resist temperature, and reduce friction.

22. Chemical Structure
● Chemical structure: all PFAS contain a chain
of carbons attached to fluorines with a
functional group at the end
○ Most PFAS compounds can be broken
down into units: (1) the hydrophobic,
nonionic tail consisting of the
fluorinated carbon chain (2) the anionic
head, having a negative charge
● PFAS owe their properties to the carbon-
fluorine bond, one of the shortest and
strongest known
https://engineering.tufts.edu/cee/sustainabilityLab/
research/validation-prediction-PFAS.htm
https://www.niehs.nih.gov/health/topics/agen
ts/pfc/index.cfm

23. Classification
of PFAS
Most common types:
● PFAA: perfluoroalkyl acids
● PFOA: perfluorooctanoate
● PFOS: perfluorooctane
sulfonate
● Polymeric: stay intact
throughout lifetime
● Non-polymeric: useful and
harmful even after degradation

24. Classification of PFAS
● Long-chain PFAS contain 6 or more carbons, short-chain PFAS contain less than 6
● The two PFAS most commonly found by water systems are legacy long-chain
compounds that have been phased out of manufacturing, perfluorooctanoate (PFOA) and
perfluorooctane sulfonic (PFOS) acids.
● Long-chain PFAS have been found to have high bioaccumulation potential compared to
short-chain
○ For example, the half-life of PFOS in the human body is 5 years or more
○ By comparison, the half-life of PFBA (a short-chain PFAS) is 3 to 4 days
● Long-chain PFAS are no longer commonly used but are easier to remove, while short-
chain PFAS are much more difficult to extract

25. Environmental Interaction
● Sources of environmental contamination include:
○ Disposal of wastes generated during primary and secondary PFAS production
○ Degradation of consumer products containing PFAS
○ Fire fighting foams used for flammable liquids and fire department training
● Environmental release mechanisms associated with these facilities include: air
emissions and dispersion, spills, and disposal of manufacturing wastes and
wastewater
● Conventional sewage treatment methods do not efficiently remove PFAS
○ Some PFAS are frequently detected in wastewater treatment plant effluents
● PFAS in an area’s wastewater indicates their presence in drinking water

26. Environmental Interaction
● PFAS have been found in domestic
sewage sludge and biosolids
● Application of biosolids as a soil
amendment can result in an
additional transfer of PFAS to soil;
then available for uptake by plants
and soil organisms
○ PFAS can then enter the food
chain through biosolids-
amended soil

27. Manufacturing and Usage
Commercial products containing PFAS:
● Paper and packaging
● Fire-fighting foams
● Outdoor textiles and sporting equipment
● Non-stick cookware
● Cleaning agents and fabric softeners
● Paints and dyes
● Adhesives
● Medical products
Major manufacturing sources:
● Textiles and leather products
● Metal plating and etching
● Wire manufacturing
● Industrial plastics
● Photolithography
https://www.ppmindustries.com/en/the-adhesive-
tape-manufacturer

28. History of PFAS

29. 3M Company
● The history of PFAS production begins with the 3M Company, founded in 1902 as a mining
venture. The company is based in St. Paul, Minnesota.
○ Has now moved on to manufacture sandpaper, abrasive materials, tapes (masking tape
and Scotch® tape brand), and more.
● In the 1940s, they began utilizing electrochemical fluorination to manufacture certain
products, introducing PFAS – aka the forever chemicals – into the everyday lives of
consumers.
● 3M Company has failed to notify the government multiple times since USEPA rules were
released in 2002.
● Even with government assistance, 3M has only spent 12% of the 10 billion taxpayer dollars
the company was allocated for PFAS clean up, and wasting this money has brought multiple
lawsuits against them

30. Health Risks: Minnesota Case Study
● PFAS have been linked to a major cancer crisis in Washington County,
Minnesota. Several major drinking water supplies were contaminated
with PFAS, allegedly from the 3M Company dumping the chemicals in
the city’s landfills.
● 3M used PFAS as a key ingredient in ScotchGuard products in Oakdale,
Washington County. It was found that the children who died were 171%
more likely to have had a diagnosis of cancer than children who died in
unaffected areas.
● In 2018, the state of Minnesota settled its lawsuit against the 3M
Company in return for a settlement of $850 million.
○ Minnesota’s attorney general sued 3M in 2010 alleging that the
company’s production of PFAS had damaged drinking water and
natural resources in the Twin Cities Metropolitan area.

31. Health Risks: Australia Case Study
● Multiple areas in Australia were contaminated with PFAS due to fire fighting activities on nearby defense
force bases, creating what they call “the Road of Death.”
● Members of these communities were exposed to PFAS primarily through the use of contaminated water
including bore and river water on their properties, and via eating locally grown foods.
● Australian Government Department of Health: “Currently
there is limited evidence that exposure to PFAS causes
adverse human health effects.”
● This is in contrast to the USEPA, which has concluded
PFAS are a human health hazard, and at high enough
levels can cause immune dysfunction, hormonal
interference, and certain types of cancer in humans.

32. Health Risks: Australia Case Study
● Recently, Australian National University’s College of Health
& Medicine conducted an investigation into the exposure
levels and potential health effects on “the Road of Death.”
● Participants referred to what they suspected was a “cancer
cluster” several times, which had occurred in a specific
geographical location in the PFAS Investigation Area
○ Participants were particularly concerned about the
onset of cancers and the deterioration of existing
health conditions
● However, ANU found no convincing evidence that PFAS
contamination caused cancer in humans
https://www.foe.org.au/water_industry_a_major_source_of_pfas_contamination

33. Current Action For Awareness & Removal
● The PFAS Action Act of 2021 was recently introduced by Michigan Representative Debbie
Dingell, and aims to set a pathway for PFAS chemical to be designated hazardous
substances.
○ This will open the door for future regulation in drinking water, as well as clean up
under other existing legislations.
○ In April, the bill passed in the House by a vote of 241 to 183.
● According to the Government Accountability Office, the Department of Defense spent $1.1
billion on PFAS clean up in 2020, and estimates it will spend $2.1 billion more in 2021.
○ Officials say it might take decades to fully address PFAS pollution.

34. Existing Regulations
● Safe Drinking Water Act (SDWA) sets enforceable Maximum Contaminant Levels (MCLs) for
specific chemicals and can require monitoring of public water supplies
○ No current MCLs established for PFAS chemicals
● EPA has issued a health advisory for PFOA and PFOS; however it serves as an informal
guideline and is non-regulatory
● EPA collected data for chemicals that were suspected contaminants in drinking water but did
not have health based-standards set under the SDWA
○ Six PFAS substances were included for monitoring
● The Toxic Substances Control Act (TSCA) includes a requirement for industry reporting of
chemicals to the EPA. To date, 330 PFAS substances have been reported.

35. Existing Regulations
● Thus, there are no federal regulations for PFAS substances in the United States.
● However, the California State Water Resources Control Board (SWRCB) Division of
Drinking Water has set some of the most stringent PFAS advisories in the country
○ The focus of our project is a well site in Orange County
○ The control board set notification and response levels to regulate PFAS state-wide

36. Ion Exchange (IX)
● IX is a water treatment method where ionic contaminants
are removed from water by exchange with another non-
objectionable ionic substance.
○ Both the contaminant and the exchange substance
must be dissolved and have the same type of
electrical charge.
● During the exchange process, any ionic contaminants in
the water are traded for “healthier” ions provided by the
exchange substance
○ The contaminant ions are then attracted or fixed to
the exchange substance and cannot pass through to
the rest of the water treatment process.
https://en.wikipedia.org/wiki/Ion-exchange_resin

37. IX Mechanism
https://www.sciencedirect.com/science/article/pii/S0045
653521002460#fig4
● Anion exchange resins are made up of
highly porous, polymeric microbeads that
are basic and water insoluble.
○ Characteristics are chosen based
on the substance being removed:
strongly or weakly basic functional
group, acrylic or styrenic matrix, and
gel or macroporous cross linking
● The resin beads have a positive functional group that is immobile with a negatively charged exchange ion
attached. The negatively charged PFAS have a greater attraction to the immobile functional group, so the
exchange ion is released and the PFAS are loaded onto the resin.
● Anion IX removes 100 percent of the PFAS for a time that depends on the choice of resin, bed depth, flow rate,
and which PFAS need to be removed

38. IX Vessel
● The IX resin is loaded into vessels.
● The contaminated solution enters the top of the vessel,
runs through a compact mixed resin bed, which will pick up
and retain the PFAS contaminants. The treated water exits
the vessel at the bottom.
○ Flow rate through the vessel is regulated by valves to
ensure there is enough contact time for the ion
exchange to take place.
○ Pretreatment is often needed before the IX vessels to
ensure the most efficient use of the ion exchange
resin.

39. Resin Regeneration
● IX resins can either be single use or regenerative
○ Since resin manufacturing has a large environmental burden, regenerative resins are
preferred
● Regeneration occurs within the vessels through a two step process:
○ Backwashing uses a back flow of water for the removal of debris such as organic matter
○ A regeneration solution, usually a brine, is back flowed through the resin to remove the
attached PFAS from the resin and replace them with chloride ions
● This process produces a concentrated waste stream of PFAS, which is typically
disposed of through incineration. However, this method, along with microbial,
sonochemical, electrochemical, and photon-based degradation are still being
researched.

40. Alternative Methods
● Granulated activated carbon (GAC) is a porous adsorption media made from organic carbon
materials which filters contaminants via a physical mass transfer process.
○ Its extremely high internal surface area contributes to adsorption, and heat is used to
activate the media surface area.
● Reverse osmosis removes contaminants by pushing the water under pressure through a
semipermeable membrane, then the contaminant is collected for disposal.
○ This method is commonly used for household water purification and production of
bottled water.
● Nanofiltration is similar to reverse osmosis, however the membrane is not as “tight”. This
method operates at a lower pressure and is less effective at removing dissolved solids.

41. Advantages and Limitations

42. Advantages and Limitations
For these reasons, we decided to model the drinking water well site with an
ion exchange vessel for PFAS removal.

43. Materials and Methods

44. Project Site Information
● The project focuses on a residential area in the Orange County Water District
○ Well Site #7 includes an existing groundwater extraction well, clear well with
a booster pump, and a chloramine disinfection system.
● The facility was designed to produce up to 2,000 gpm of drinking water for
delivery to the distribution system. The distribution system will go to a water
treatment facility for further disinfection.
● The pump station and chemical facilities were designed to host a future additional
well and booster pump for a higher production rate of up to 4,000 gpm.

45. Well Site Water Quality

46. IX Resin
We have chosen the Purolite PFA694E resin.
● Reduces PFAS to non-detect levels ranging from 1 – 5 parts per trillion
● Has a polystyrenic backbone which is crosslinked with divinylbenzene and a complex
amino functional group
● Removes PFAS via a dual mechanism of ion exchange and adsorption
● Effective on short and long chain PFAS
● Very high operating capacity and a higher total exchange
capacity than its competitors
● Regenerative

48. Purolite PFA694E Characteristics

49. Governing Equations
● Langmuir Isotherm
Where C is the dissolved chemical species, S is an adsorption site, CS is the chemical
bound to the site, Keq is the equilibrium constant governing the reaction, and Stot is the
total site concentration.

50. Governing Equations
● Mass Balance

51. Hydraulic Calculation Assumptions
Criteria Assumptions
Pumping System Upgrade existing pump to provide 2,000
gpm flow
Number of pumps: 1 pump
Static Water Level and Drawdown Level Suction Side HWL: 99 ft
Suction Side LWL: -8 ft
Pump System Conditions Intake Elevation: -119 ft
Discharge Elevation: 307 ft (highpoint in
pump piping)
Min. Roughness Factor: 130
Max. Roughness Factor: 140
Altitude: 302 ft
Water Temp.: 60 degrees F

52. Well Schematic
Diagram

53. Pump System Head
Loss and Motor
Equations

54. Modeling
● To model the PFAS accumulation and the concentration gradient through the
IX resin, STELLA will be used.
● To model the influent and effluent concentration of PFAS through the IX
vessel, SuperPro will be used.
● To model the pump and pre filtration unit, Solidworks will be used.
● To model the whole site process, AutoCAD and Google SketchUp will be used.

55. IX Resin Model
● Modeling PFAS accumulation in the ion exchange vessel in Stella

56. Stella Modeling Report

57. ● Modeling the concentration gradient in the ion exchange vessel also in STELLA

58. Stella Modeling Report
Concentration
(ng/L)

59. ● Modeling initial and final PFAS concentrations using SuperPro

60. SuperPro Modeling Report

61. Results For IX Vessel, Prefiltration Unit,
Pump, & Site Process with Solidworks &
AutoCAD

62. Purolite PFA694E Requirements for IX Vessel
Number of Trains 2
Vessel Diameter 12 ft
Media Volume per Vessel 420 ft3
Total Media Volume 1680 ft3
Vessel Area 113 ft2
Bed Depth 3.7 ft
Linear Velocity 8.8 gpm/ft2
Specific Flow Rate 2.4 gpm/ft3
With these configurations, the lag vessel breakthrough will occur at approximately
189,000 bed volumes. This is equal to about 412 days if the system ran 24/7 at 2000
gpm.

63. IX Vessel
● For the IX vessel, we chose Evoqua Water Technologies to provide the vessel
since they are able to make the vessel any size we need.
● The following Solidworks model is based off of an Evoqua vessel and the
dimension requirements from the Purolite resin.

64. IX Vessel 3D Model
Water Inlet
(10 in
diameter
pipe)
Regeneration
Inlet (20 in
diameter
pipe) Resin Bed
(3.7 ft deep)
Treated Water Outlet
(10 in diameter pipe)
Waste Outlet (20 in diameter pipe)
Vessel diameter: 12 ft

65. Prefiltration Unit
● The chosen prefiltration unit is a Yardney Angled Centrifugal Sand Separator.
● From Yardney’s given flow size charts, the model chosen for a 2,000 gpm flow rate is a
PCS-100LA. It can handle flow from 1300-2300 gpm
○ Particle size max: 1.5”
○ Removes sand, rock, grit, and other inorganic contaminants with fine filtration
down to 75 microns.
○ 10” inlet/outlet diameter; 10” piping from prefiltration unit to IX vessel
● There will be two prefiltration units in series in order to maximize the amount of water
that can be treated.

66. Prefiltration Unit Models
10” inlet
10”
outlet
2” purge
outlet

67. Pump System Head Loss
and Motor Calculations
Cross sectional area: A=π*r2
Where: D [10 in]
r [0.417 ft]
A [0.55 ft2]
Velocity: V=Q/A
Where: Q [2000 gpm = 32.68 fps]
V [59.92 fps]
Velocity head: Hv=V2/2g
Where: g [32.2 ft/s2]
Hv [55.75 ft]
Pipe Friction Head loss: HI=L*Sf
Where: Sf= (10.44Q1.85)/(10.441.85 *D4.8655)
Sf [0.001175 ft/ft]
L [216.64 ft]
HI [0.255 ft]
Input Shaft Power: Ps=(Q*TH)/(Cf*E)
Where: TH [107 ft]
E [80% efficiency]
Cf [3960 for english units]
Ps [67.55 hp]]

68. Pump: Original Choice
● For 2000 gpm flow rate, the WaterBoss Lineshaft Turbine Pump by
Wolf Customized Pumps was chosen. Specifically model 14HME.
● This pump was chosen because it can handle deep well types and
the materials it’s made of allow it to handle harsh conditions (like
the high flow rate and being underground).

69. 1800 RPM Performance
Curve for original pump
choice
● This performance curve was
provided by Wolf.
● Overall , this pump won’t be able to
provide enough power, according
to the calculations.

70. Pump: New Choice
● The new chosen pump is just one model up from the previous,
which is a WaterBoss Lineshaft Turbine Pump by Wolf Customized
Pumps, specifically their 14HMO.
● It can handle a flow rate of 1500-3250 gpm
● The bowl diameter is 14” and it is made of glass lined CL30 cast
iron. The impeller material is C876 BRZ with an enclosed style.
● The 10” piping can connect the pump to the pre-filtration unit with
a fitted connector between the the bowl and the piping.

71. 1770 RPM Performance
Curve for new pump
choice
● This performance curve was
provided by Wolf.
● The new pump is able to provide
more than enough power and can
accommodate the system head.

72. Site Process Flow Model

73. Pump and Prefiltration

74. IX Vessel Train

75. Site Model: Overhead View

76. Site Model: Close Up

77. Option 1

78. Option 2

79. Cost Estimate
● Ion exchange vessel
○ $200,000
● Resin
○ $1,000 per cubic foot
■ $1,680,000 for 4 vessels
● Pre-filtration unit
○ $6,000
● Pump
○ $7,000
● Warehouse construction: $400,000
● Total: $

80. Recommendations for Maintenance
● The resin will need to be regenerated before the 412 day breakthrough time to keep the
effluent concentration less than 2 ng/L
○ Backwashing will occur before the regeneration to remove any accumulated debris or
fine resin particles
○ Regeneration with a 0.5% ammonium chloride brine results in higher PFOA and PFOS
recovery rates
● Eventually, the resin will be exhausted, and it will no longer be beneficial to regenerate as the
removal efficiency decreases with each regeneration.
○ Since the lifespan is dependent on many factors such as temperature, oxidants,
organics, and other foulants, it is difficult to predict the exact replacement period. Most
strongly basic anion exchange resins last 5-8 years.

82. Acknowledgements
Alex Lin, P.E., AECOM
Dr. Alessandro Franchi, P.E., AECOM
Dr. Darnault, Ingénieur
Dr. Xiao
Dr. Drapcho
Dr. Lipscomb
And the wonderful Capstone Team: Lauren Todd, Shirin Udwadia, Rachel Burger, Caroline Packard,
Sophia Della Rocca

83. Thank You