Call for Papers - African Journal of Biological Sciences, E-ISSN: 2663-2187, ...
Capstone
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
December 2nd, 2021
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.
10. 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.
11. 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
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 1: To research PFAS and establish their general structure, usage, interaction with the environment,
human health effects, and current federal and state regulations.
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 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.
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 3: To determine and compare different vendors and technologies for the ion exchange vessel.
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 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).
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 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.
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 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 and COMSOL.
18. 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).
19. 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.
20.
21. 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
23. 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 in animals
○ They 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.
24. 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 bonds known
https://engineering.tufts.edu/cee/sustainabilityLab/
research/validation-prediction-PFAS.htm
https://www.niehs.nih.gov/health/topics/agen
ts/pfc/index.cfm
25. 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
26. 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
27. 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
28. 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
29. 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
31. 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
32. 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.
33. 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.
34. 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
35. 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.
36. 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.
37. 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
38. 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
resin
○ The contaminant ions are then attracted or fixed to
the resin and cannot pass through to the rest of the
water treatment process.
https://en.wikipedia.org/wiki/Ion-exchange_resin
39. 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
40. IX Vessel
● The IX resin is loaded into vessels.
○ 3:1 ratio of diameter to height is typical
● 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 resin.
41. 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 and replace them with chloride ions
● This process produces a concentrated waste stream of PFAS, which is typically
disposed through incineration. However, this method, along with microbial,
sonochemical, electrochemical, and photon-based degradation are still being
researched.
42. 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.
46. Measuring PFAS
● Cold water tap
● Hot water tap
● Canned seltzer water
● Water fountain
● Water bottle fill station
● Filtered tap water
● In house DDI water
47. Liquid Chromatography - Mass Spectrometry (LC-MS)
● Analytical method that combines
features of liquid-chromatography
and mass spectrometry to identify
substances within a sample.
● The method used was similar to
EPA Methods 537b and 533 for
standard testing of PFAS
48. Lab Work
● Prepared samples by pipetting each into tubes and adding methanol
● Created standards for the creation of a calibration curve
○ Started with 0.45 mL of 25 ppt of PFOS stock solution, 5% methanol
in LC-MS water.
○ Performed 10 serial dilutions to get to a final concentration of
0.024414 ppt
● The mobile phases created to carry the samples through the system
○ 1 L ammonium hydroxide buffer solution
○ 1 L acetonitrile
49. 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.
51. IX Resin
We have chosen the Purolite PFA592E 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 high total exchange
capacity compared to its competitors
● Regenerative
54. Governing Equations For Adsorption
● Freundlich Isotherm
Where qe = the mass of PFAS adsorbed per mass of resin
Ce = the equilibrium concentration
KF and n = Freundlich constants relating to the resin
adsorption capacity and intensity
55. Governing Equations for Adsorption
● Differential equation for the pseudo-second order model
Where qe = the mass of PFAS adsorbed per mass of resin
qt = the adsorption capacity at time t
k2 = rate constant from 2nd order kinetic model
t = time
56. Hydraulic Calculation Assumptions from AECOM
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
58. Pump System Head
Loss and Motor
Equations
1) Cross sectional area of pipe (A) in ft2
A=π*r2
Where: r= desired radius [ft]
1) Velocity (V) in fps
V=Q/A
Where: Q= desired flow rate [cubic fps]
1) Velocity Head (HV) in ft
HV=V2/2*g
Where: g= 32.2 ft/sec2
1) Pipe Friction Headloss (H)
H= f*(L/D)*(HV)
where : f= friction factor
L= length of pipe [ft]
D= diameter of pipe [ft]
1) Pump Power Required (P) in Hp
P= (Q*TH*p)/(3960*n)
Where: TH= total head [ft]
p= density [lb/ft3]
n= efficiency of the pump
59. Modeling
● To model the PFAS accumulation and the concentration gradient through the
IX resin, STELLA and COMSOL will be used.
● To model the pump and pre filtration unit, Solidworks will be used.
● To model the whole site process, SuperPro, AutoCAD, and Google SketchUp
will be used.
63. Results
Source PFOS Concentration (ng/L)
Cold tap water 24.26
Hot tap water 23.49
Polar canned seltzer water 24.28
Water fountain near room 104 24.31
Water bottle fill station 25.03
Filtered tap water 24.84
In house DDI water 23.94
64. Results For IX Resin Uptake and
Concentration Gradient with STELLA &
COMSOL
65. Purolite PFA694E Requirements for IX Vessel
Number of Trains 2
Total Media Volume 1680 ft3
Media Volume per Vessel 420 ft3
Vessel Diameter 12 ft
Bed Depth 3.7 ft
Vessel Area 113 ft2
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.
71. Results For IX Vessel, Prefiltration Unit,
Pump, & Site Process with Solidworks,
SuperPro, AutoCAD, & Google SketchUp
72. IX Vessel
● For the IX vessel, we chose Evoqua Water Technologies since they are able to
make custom IX vessels.
● The following Solidworks model is based off of an Evoqua vessel diagram
with the dimension requirements from the Purolite resin.
73. IX Vessel 3D Model
Resin Bed
(3.7 ft deep)
Water Inlet
(10 in
diameter
pipe)
Regeneration
Inlet (20 in
diameter
pipe)
Treated Water Outlet
(10 in diameter pipe)
Waste Outlet (20 in diameter pipe)
Vessel diameter: 12 ft
74. 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.
76. Pump System Head Loss
and Motor Calculations
1) Cross sectional area of pipe (A) in ft2
A=π*r2= 0.55 ft2
Where: r= 5 in= 0.4167 ft
1) Velocity (V) in fps
V=Q/A= 9.81 fps
Where: Q= 2000 gpm= 5.351 cubic fps
1) Velocity Head (HV) in ft
HV=V2/2*g= 1.5 ft
Where: g= 32.2 ft/sec2
1) Pipe Friction Headloss (H) in ft
H= f*(L/D)*(HV)= 14.348 ft
where : f= 0.02
L= 400 ft
D= 10 in= 0.833 ft
1) Pump Power Required (P) in Hp
P= (Q*TH*p)/(3960*n)= 18.4-27.9 Hp
Where: TH= 207- 315 ft
p= 62.4 lb/ft3
n= 95%= 0.95
77. Pump Choice
● Originally a pump was chosen just based on the required flow
rate, without the pump system head loss and motor
calculations
● 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 a flow range of
1500-3250 gpm and deep well types in harsh conditions.
● This pump is made of glass lined CL30 cast iron and C875 BRZ.
78. 1800 RPM Performance
Curve
● This performance curve was
provided by Wolf.
● After the pump head loss and
motor calculations, it was
determined that this was an
appropriate choice for the well
system.
● This was based on the power
calculation.
89. 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: $ 2,293,000
90. Recommendations for Maintenance
● The resin will need to be regenerated before the 412 day breakthrough time to keep the
effluent concentration of PFOA and PFOS 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.
91.
92. 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
Sophia
Read whole outline
First we have introduction which include...
We will now go into our introduction
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Orange county is the reference for our project form aecom
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OUr rationale of our project is
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More emphasis on the commas!!
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Need to put citation
Edit the volume
Put intro to the video: this video is John Oliver.. on the Late Night Show talking about how prevalent PFAS is in the world.
Caroline
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Put intro to the video: this video is John.. on the Late Night Show talking about how prevalent PFAS is in the world.
sophia
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The first 3 are...
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Caroline will now discuss the remaining tasks
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And finally task 8…
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Sophia-
Our project involves science, technology, engineering, mathematics, with a environmental protection and human health aspect. At the center, our project is to provide access to clean drinking water for all which happens to be a a grand challenge.
Science, Technology, Engineering, & Mathematics
(STEM)
Make it bigger
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grand challenge
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Caroline
Now we’ll be looking into our literature review findings...
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Break down this chart a little more
They can be classified as polymeric (seen here on the left) and non-polymeric PFAS (seen here on the right), meaning they can either stay intact throughout their lifetime, or they can be broken down in to smaller PFAS which are still useful as well as harmful even after degradation
Polymeric compounds are larger molecules that are made up of repeating units
Non polymeric compounds are the results of the repeating units breaking apart and degrading, and can still be used in manufacturing as non polymeric PFAS
Caroline
Caroline
found in water, air, fish, and soil
Caroline
Caroline
The United States has yet to ratify the Stockholm Convention amendments
Perfluorooctyl = PFAA
Caroline
Diving into the 3M company…
Caroline
Caroline
Caroline
Shirin
So now what is some current actions for awareness and removal
Shirin
What are some existing regulations for PFAS
What are some existing regulations for PFAS
Shirin
Lauren will now discuss ion exchange
Lauren
Cutting edge
Key words
Our project works on the the number ½ problem in the world water and PFAS
Army study with the blood contamination
For ion exchange video lets just restate what she said in the video. Don’t delete the video just yet
Lauren
More about how they work with the functional groups
Explain more about functional groups and structure of everything
But maybe just for the one we choose
Show absorption and ion exchange and structure
Confront reactions! Don’t avoid them
Need to go more in depth and spend longer about the science of how this works
*** use ix for all ion exchange
Lauren
Find a more modern ion exchange vessel
More simplistic model
Label each one
Actual model of beads and vessel
Typical to reduce pressure drop
Lauren
Lauren
Lauren
Lauren
Lauren - Next we will be discussing materials and methods
We wanted to understand and implement the process of testing for PFAS in water sources and measure PFAS in Clemson water, so samples were collected from …. List locations
Distilled deionized water
We had the opportunity and connected with Dr. Lipscomb and he was generous to assist us in using his lab located in Rich lab. We used LC-MS
The liquid chromatography concentrates the samples by passing them through columns that capture the pfos and then releases them to the mass spec
The Mass Spectrometry part slams molecules, called precursor ions, into gaseous nitrogen, and they break into fragments with a known mass and ratio, which is used to determine which type of molecule it is.
We prepped our samples by pipetting them into small test tubes and adding 5% methanol to ensure PFOS isnt leaching to the walls
We created standards to create a calibration curve. by doing 10 serial dilutions with ??? , LCMS water and methanol
We created the mobile phase?????
Pending analysis some issues with the lcms
Now lauren will talk about the project site information
The ammonium hydroxide buffer solution deprotenates
At this time we had access to previous work
Went into the lab for a few hours a week
We prepared our samples
Created standards for a calibration curve
The mobile phase that
Ionization efficiency
Added methanol to our samples to take in account of pfas sticking to the walls of the plastic tubes
1 L 1% acetic acid solution - reprotenate cartridge to capture pfas, short period of time then switch to water
1 L LCMS water - carrier solvent, keep things moving to concentration capture system
1 L 100% methanol - wash cartridge, removes pfas
Reverse phase LC
SPE function solid phase extraction
We wanted to see how much PFAS is actually in the water that we use daily
Dasani bottled water that is what is distributed in every vending machine around campus
Dasani bottled water is what is in vending machines around campus
lauren
Lauren
Change ug to microgram symbol for iron
So for PFOS, we want an 92% reduction, and for PFOA, an 87% reduction
Lauren
Pfas specific
equations
Lauren
Highlight that resin
Fix formatting
Explain more about functional groups and structure of everything
But maybe just for the one we choose
Show absorption and ion exchange and structure
Confront reactions! Dont avoid them\
Dont say as you can see, say compared with other resin the purolite has a higher exchange capacity
lauren
Sorption coefficient Kd = qi’(ci) ?
Equilibrium adsorption isotherms are used to determine the capacity, surface properties, and affinity of the resin. This is specific for the species being adsorbed, which in our case is PFAS. Thus this isotherm is an empirical model that is based on a study conducted with a similar resin and PFOA, where it was determine that the feundlich isotherm is the most appropriate.
Log of qe on y axis and log of ce on x axis, 1/n is the slope,
-type out onto slide
Lauren
Remove the 7.3.6
Explain absorption for Kd
And explain the difference with the pfas not moving and absorption
This is the differential equation for the pseudo second order model, which describes the rate of adsorption of the PFAS, where the rate is equal to
Rachel
Rachel
Provided by AECOM. Shows where the water intake is and where the pump is. Also shows that the design static head range is about 208’ to 315’
Rachel
Rachel
Shirin
Now we will dive into the results for PFOS testing on clemson water
Precursor ion,
slam into nitrogen
product ions 2 unique to determine its what we got
Here is the calibration curve that was obtained by the standards created with the corresponding equation. This graph and equation is used to obtain the concentration of PFOS. The software outputs a response graph that you will see in the next slide and using that response value you can get concentration off of this graph.
Unfortunately there were some issues with the LCMS which caused tests to get backed up so we have not gotten our results back
Instead Dr. Lipscum is allowing us to use some results he got when he tested water from Rich Labs
This still proves that PFAS is prevalent in our water sources
LC
Sample matrix and trying to find analytes in it that are dilute so need to concentrate on a weak anion exchange cartridge. With waex protenate it with acetic acid
Protenate polymer grabs pfas
Deprotenate release it
MS- make some ions, pfas makes negative ions, mass spec electrostatically sucks in vac and controled by electronic optics, slam into detector and look at M/Z mass to charge ratio. Precursor ion- slam the crap out of it into clean nitrogen molecules and break it apart. Single charge follows one part. 2 product ions. What and how much it is as long as using good standards/controls
Here is a response graph or a chromatogram from the water bottle fill station in rich. You can see some spikes in the beginning and dr. lipscum thinks that those are Isomers of same compound. After the spike you see some background noise which is coming from the system proving that pfas is everywhere. The software Uses the counts and area under the curve to output a response number and the response is plugged into the y value from the calibration curve to get a concentration
Shirin
Area under curve gives idea of what the concentration is
Isomers of same compound are what the spikes in the beginning are
After the spike you see some background noise which is coming from the system proving that pfas is everywhere
Delay column ???
All of the samples have concentrations around 20 ng/L which is close to the value AECOM provided to from the site we are working at that has a concentration of 23.5 ng/L of PFOS
Avg of lowest 5 blanks calculate concentration
Compare to ND levels
Appears to be there bc we have response greater than blanks
Lod vs loq
Sophia - now we will discuss the results for ion exchange resin uptake and concentration gradient with stella and comsol
Rachel
From the Purolite sales representative, these are the requirements for the ion exchange vessel in order to use this particular resin.
-clarify lead and lag configuration
Based on literature review, the vessels configuration will be 2 in series, the first is the lead and the second is the lag vessel. This is common for ion exchange to reduce the frequency of regeneration or resin replacement. This lead-lag configuration is also called a train, and our model will have two train in parallel to account for the high flow rate. The total media volume was determined based on the total exchange capacity of the resin, at 0.9 eq per L of resin, and how much PFAS needed to be removed. The volume per vessel is the amount of resin for each of the four vessels. The diameter and depth were determined based on the volume and with a 3:1 diameter to height ratio. THe linear velocity was calculated as….. And the specific flow rate was calculated as...
Lauren
It was determined that PFOA will be the driver for resin exchanges, and that the PFOS will be reduced to below the 2 ng/L requirement well before the PFOA will. So, this model is based on the chemical properties of PFOA.
Lauren
Ripening phenomena?? Or does it make it slower
Simulate upper limits: 50
Small medium large
10, 39.8, 50, 100
Fix typo
Lauren
Ripening phenomena?? Or does it make it slower
Simulate upper limits: 50
Small medium large
10, 39.8, 50, 100
Fix typo
625 days for 10 ng +213
320 days for 20 ng -95
Lauren
Ripening phenomena?? Or does it make it slower
Simulate upper limits: 50
Small medium large
10, 39.8, 50, 100
Fix typo
140 days for 50 ng
65 days for 100 ng
Mention comsols into the materials and methods
Put in governing equations
Looking into creating a gif for the simulation\
We also modeled the parameters from Stella in Comsol, to show the concentration gradient of the resin as time continues. This shows a vertical cross section of the resin in one vessel, with a length of 12 ft and a depth of 3.7 ft. The system can be modeled as a plug flow, with a higher concentration at the top as the PFAS are adsorbed where they first interact with the resin, and a lower concentration at the bottom towards the effluent. However as time progresses and the breakthrough time of 412 days is reached, the resin reaches capacity and the concentration is essentially uniform throughout the resin.
This model also used the Freundlich isotherm, as well as brinkmans equations for porous media high-velocity flows.
Rachel
Rachel
Rachel
The resin bed is 3.7ft with 5 layers, each layer is about 9 inches
The water inlet and outlet pipes need to be 10in in diameter to fit the pre-filtration unit, which will be talked about in the next slide.
Rachel
Rachel
The pre-filtration unit has a set 10in inlet and outlet. So the pipes connecting to this unit to the IX vessel and the pump needs to be 10in in diameter.
Rachel
These are the pump system head loss and motor calculations. In order to have a 10in diameter the area will need to be...
Rachel
We were told that the site already has a pump, however AECOM cannot disclose that information due to their client. So we decided to choose a pump and assume that is what they have.
Rachel
Be able to explain the pump curve.
Lauren
Find governing equations which they use
Lauren
Show range of PFAS concentrations
Try to make it less blurry
This was also used later to determine the water composition after the ion exchange
This data sheet display what chemicals are in the water after leaving the ion exchange system. This water will then travel to a near by water treatment facility.
TDS: total disolved solitds
Rachel
This shows the site process flow as a whole with the pump, a pre-filtration unit, and 2 trains of IX vessels (the two trains are in series, while the vessels in the trains are in parallel.
Rachel
This shows where the well site, pump, and the pre-filtration unit are in the site process flow.
Rachel
This shows one of the two IX vessel trains. The vessel on the left is the leading vessel while the one on the right is the lagging vessel. This means that the water first goes through the leading vessel then to the lagging vessel. The leading vessel will collect more PFAS than the lagging vessel.
Sophia
This aerial view displays where our site will be located in relation to the water source and residential living. Well site #7
sophia
This model displays a close up view of the two options for the site where the ion exchange system will reside
sophia
Option 1 is a smaller shed. Inside the ion exchange vessels would reside with most of the pumping being in ground
sophia
Site two is large with the pumping systems being above ground. This site might be better as more maintenance and as regulations change, parts can be regularly replaced.
sophia
Sophia:
Cost from SuperPro
Cost:
Covid shortages so more expensive
For construction
Sophia
-doble check resin costs with purolite and alex
-recommended testing frequency?
Sophia
Sophia-
Bring it all back together
Our project involves science, technology, engineering, mathematics, with a environmental protection and human health aspect. At the center, our project is to provide access to clean drinking water for all which happens to be a a grand challenge.
Science, Technology, Engineering, & Mathematics
Environment health?
grand challenge
Write what grand challenge is on there , make it easier to see
Pictures, graph, from superpro into which circle they fall under, change text to fit so that pictures are the center
To tie everything together…., or in conclusion, we have…
-in one of boxes show lab pictures and result, show design, and stella
Shirin
Collect, calibrate, prepare standards, run tests - materials and methods
Results in results
Similar to the epa method