treating emerging contaminants

Treating Emerging Contaminants

Evaluation of the removal efficiency of activated carbon on

PFAS in drinking water

Wendy Schultz

Per- and Polyfluoralkylsubstances (PFAS)

Most people in the United States have been exposed to PFAS and have PFAS in their blood.

Data Source: Centers for Disease Control and Prevention. Fourth Report on Human Exposure to Environmental Chemicals (January 2017).

Michigan PFAS Sites

Michigan PFAS Sites

Project Objective

The objective of this project was to assess the effectiveness of granular activated carbon for removing PFAS from drinking water sources.

Project Drivers

Safe water for our customers

Meeting future regulations

Agenda / Topics

Overview of PFAS and Granular Activated Carbon

Background of the finding the problem

Project and Methodology

Key Findings/Results

Conclusion/Future

What are PFAS ?

What are PFAS ?

PFCs

What are PFAS?

PFAS

Perfluoroalkyl Polyfluoroalkyl

Focus on two perfluoroalkylsubstances

CCCCC

CCC

C

CCC

CC C

C

>3,000 Man-made chemicals

Fire-fighting foam

Whiteman AFB, Missouri

B2 Stealth Bomber

B2 Stealth Bomber

Fire-fighting foam

Industrial Sites

WWTP

Landfills

Water & Air

Released into the food chain

Persists indefinitely in the environment

Builds up

Human Exposure

Found in fresh food

Found in fast food packaging

Found in fast food

Found in home-cooked food

Found in house dust

Found in cleaning products

Found in stain-resistant coatings

Found in personal care items

Found in fish

PFAS in Michigan fish

Granular Activated Carbon (GAC)

How is GAC made?

Why is it called activated carbon?

What makes it granular activated carbon?

2 grams of GAC

How does GAC work?

Adsorption vs. Absorption

(think Adhere vs. Absorb)

Adsorption Capacity

Third Unregulated Contaminant Monitoring Rule (UCMR3)

Contaminant (ppt)Dec

2013Mar

2014Jun

2014Sep

2014

perfluorooctanesulfonic acid (PFOS) ND 43.0 ND ND

perfluorooctanoic acid (PFOA) ND ND ND ND

perfluorononanoic acid (PFNA) ND ND ND ND

perfluorohexanesulfonic acid (PFHxS) ND ND ND ND

perfluoroheptanoic acid (PFHpA) ND ND ND ND

perfluorobutanesulfonic acid (PFBS) ND ND ND ND

PFOS and PFOA combined in the drinking water contamination near Rockford measured at 58,930 ppt.

Ann Arbor Water Treatment Plant

Ann Arbor Water Treatment Schematic

PRIMARY

FLOC

PRIMARY

SETTLING

CO2

RECARBSEC

SETTLING

Huron River

Water

LIM

EGAC

FILTRATION

Finished

Water

CL

2

Turb =10-20

pH = 10.8-11.2

TAlk =50-70

O3

OZONESEC

FLOC

SEC

RAP MIX

PRIMARY

RAP MIX

Well

Water

Well

Water

Turb = 2-20

pH = 7.8-8.2

TAlk = 275

Hard = 325

AM

PO

LYM

ER

CO2

PH

OS

PH

AT

E

NA

OH

FLU

OR

IDE

RECARB

Turb = 20-40

pH =10

TAlk =30-50

Turb =0.05-0.2

pH =9.3

TAlk =30-70

Hard =150

Ann Arbor Treatment Diagram(

Investigation

This Photo by Unknown Author is licensed under CC BY-NC-ND

Huron River

Water SupplyOptional statement

152 NPDES sites

Huron River

Image courtesy of Tim Kiser

Huron River PFAS

Ann Arbor Water Treatment Plant

Filter Gallery

Filter Gallery

Our usual configuration

6” sand

~18” GAC

Water out

Water in

29” GAC

Water out

Water in

Filter #1

Filter #15

6” sand

~18” GAC

Water out

Water in

Sampling Methodology

Filter #1 PFOS

Filter #1 PFOA

Filter #15 PFOS

Filter #15 PFOA

Project Summary

Conclusion

Future

Wendy Schultz

Ann Arbor Environmental Services Laboratory

wschultz@a2gov.org

Contact

AppendixReferences Buck et al 2011. Perfluoroalkyl and Polyfluoroalkyl Substances in the Environment: Terminology, Classification, and Origins. Integrated Environmental Assessment and Management. v7, (4), pp. 513–541.

CDC. 2009. Fourth National Report on Human Exposure to Environmental Chemicals. Atlanta, GA: Centers for Disease Control and Prevention. p. 247 –257.