electron beam treatment for potable water reuse: removal of … · 2017. 4. 27. · perfluorinated...

Exploiting eBeam Technologies for Cleaning, Healing, Feeding, and Shaping this World and Beyond…

Electron Beam Treatment for Potable Water

Reuse: Removal of Bromate and

Perfluorooctanoic Acid

B. Batchelor, S.D. Pillai, L. Wang and V.S. Botlaguduru

National Center for Electron Beam ResearchAn IAEA Collaborating Center for Electron Beam Technology

Texas A&M University, USA


Water is a Precious Commodity


Abbreviated Contaminant List of Concern in Texas’ Reclaimed

Water (TWDB, 2015)

Chemical Contaminants Microbial Contaminants

Disinfection by products (bromoform, bromate, chloroform, trihalomethanes)

Cryptosporidium oocysts

Household products and food additives (Bisphenol A, Perflurooctanoic acid, Perfluorooctane sulfonate)

Giardia cysts

Estrogenic compounds (17β-estradiol) Enteric viruses, Norovirus

Total coliforms, E.coli

Bacterial pathogens


➢ What and Why Bromate?

❖ Formation

Bromate is a disinfection by-product, primarily formed

when ozonating bromide-containing waters

a) Molecular ozone mechanism

b) Hydroxide radical mechanism


➢ What and Why Bromate?

❖ Health Impact & Regulation

a) Renal cell cancer

b) Classified as a substance possibly carcinogenic to

humans by International Agency for Research on Cancer (IARC)

c) Maximum contaminant level: 10 μg/L


Experimental System

• Synthetic waste water to simulate reclaimed water– Revere osmosis water

– pH 7.3

– 50 mg CaCO3/L alkalinity

– 50 µg/L Dissolved organic carbon (from fulvic acid)

• Fulvic acid chosen since mol weight < 1000 Daltons used as surrogate for NOM


Experimental System

• Samples prepared under anaerobic system

• Sample volumes ~ 30 mL

• Sealed bags to maintain anaerobic conditions

• Analytical technique

– BrO3- and Br- and F- measured using ion

chromatography


Effect of Nitrate on Bromate Removal

20 mg/L

10 mg/L

5 mg/L


Scavenging Model for Effect of Nitrate on Bromate Dose

Constant


Effect of Alkalinity on Bromate Dose Constant


Effect of pH on Bromate Dose Constant

pH 5.0

pH 7.3pH 9.0


Effect of Dissolved Oxygen on Bromate Removal

Without dissolved oxygen

With dissolved oxygen


Perfluorinated Chemicals (PFCs)

• Perfluorooctanoic acid -PFOA: C7F15CO2-

• Perfluorooctane sulfonate – PFOS C8F17SO3-

Widely used in consumer products (carpets and

fabrics)

Widely used in fire fighting foams


PFOS & PFOA


Perfluorinated Chemicals (PFCs)

• Extremely mobile in aquifers

• Contaminating drinking water wells

• PFOA and PFOS are extremely stable

– C-F bond ~ 9-116 kcal/mole)

• PFOA and PFOS have entered the food chain

– Breast milk, blood, umbilical cord blood, wildlife

• US EPA health advisory threshold : 70 ng/L


Remediation Technologies Attempted

• In situ chemical oxidation

• Bio-augmentation using vault proteins

• PFC-coagulant

• Photochemical approaches

• Electro microfiltration

• Sonochemical decomposition

• Cobalt-60 irradiation


Effect of Nitrate on PFOA Defluorination

20 mg/L

0 mg/L

NO3- (mg/L) Defluorination(%)

0 34

5 70

10 76

20 93


Effect of Alkalinity on PFOA Defluorination

100 mg/L

0 mg/L

Alk (mg/L) Defluorination(%)

0 54

25 72

50 76

100 95


Effect of Fulvic Acid on PFOA Defluorination

FA(μg /L) Defluorination(%)

0 100

25 89

50 77

100 72

0 μg/L

100 μg/L


Effect of Dissolved Oxygen on PFOA Defluorination

With dissolved oxygen

Without dissolved oygen


eBeam eliminates toxicity of wastewater

effluent based on V.fischeri test

-35

-30

-25

-20

-15

-10

-5

0

5

10

0 10 15

% Li

ght l

oss (

-) or

gai

n (+

)

Dose (kGy)

Toxicity of eBeam processed effluents


Take-Home Messages for eBeam-based Degradation

of Chemical Contaminants

# 1 Electron beam (eBeam) irradiation has been tested to remove bromate and peflurooctanoic acid (PFOA) in synthetic wastewater effluent simulating potable water reuse

# 2 A simple model has been developed for bromate degradation, and a pseudo one-component model has been developed for PFOA defluorination

# 3 eBeam treatment is a viable option to treat reclaimed water if dissolved oxygen levels are controlled and nitrate levels can be modulated

# 4 Transportable eBeam systems are needed to address contaminated groundwater situations

Suresh D. Pillai

[email protected]

http:// ebeam-tamu.org

979. 458

electron beam treatment for potable water reuse: removal of … · 2017. 4. 27. · perfluorinated...

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