New Horizons(AOPs): A Study in

Potable Groundwater

Application

Outline

Introduction

AOPs vs. Traditional VOC Treatment

AOP Chemistry Basics

1,4 Dioxane

Pilot Study and Results

Introduction

Presenter: Andrew Manfredi– B.S. in Chemical Engineering with minors in Environmental

Engineering, Chemistry, and Math from Manhattan College

– Four years of experience in water industry at H2M

Presenter: John Collins, P.E.– B.S. in Civil Engineering from Clemson University

– 14 years of experience in water industry at H2M

AOP vs. PTA

PTA moves contaminants to the air (liquid phase to gas phase)

AOP vs. GAC

GAC moves contaminants from the water to the media (liquid phase to solid phase)

AOP vs. PTA vs. GAC

AOPs destroys the contaminants within the process

AOP Chemistry Basics

‘Flow-through’ treatment similar to GAC

Unique: combines UV and chemical oxidant

Complicated chemical reactor

AOP Chemistry Basics

AOP in three steps:– Form oxidant

– Initial oxidation of VOC compound

– Subsequent oxidation of VOC

AOP goal = produce hydroxyl

radicals

Hydroxyl radicals (OH) are

strong oxidizers

Multiple ways to create:– Hydrogen peroxide + ozone

– UV + hydrogen peroxide (H2O2)

– UV + titanium dioxide (TiO2)

Oxidation

Species

Oxidation Power

[V]

Flourine 3.03

Hydroxyl Radical 2.80

Atomic Oxygen 2.42

Postively charged

hole on TiO2

2.35

Ozone 2.07

Hydrogen

Peroxide

1.77

Permanganate 1.67

Hypochlorous

Acid

1.49

Chlorine 1.36

Iodine 0.54

Hydroxyl Radical

UV light cleaves the O-O bond creating two hydroxyl

radicals:

VOC Breakdown

Really, really, really complex

Multiple pathways

Multiple intermediates

Very very fast

Determine rate limiting step

Organic

Molecule

Rate Constant

[mol/L-sec]

Chlorinated

alkenes

109 to 1011

Phenols 109 to 1010

N-containing

organics

108 to 1010

Aromatics 108 to 1010

Ketones 109 to 1010

Alcohols 108 to 109

Alkanes 106 to 109

VOC Breakdown

Still with me?

VOC Breakdown

1,4 Dioxane

WATER + CO2

AOP + GAC

1,4-Dioxane

That’s not regulated!!!

UCMR-3 Contaminant of Concern

So, it probably will be…

…and it’s a probable human carcinogen

HRL: 35ppb = additional 1:100,000 cancers

HRL: 0.35ppb = additional 1:1,000,000 cancers

Treat with AST? 10,000:1 A/W ratio

Treat with GAC? <30 day changeout for

80,000 pounds

1,4-Dioxane55 total entry points with

>0.35 ppb detection

13 water suppliers

Max: 33 ppb

79 total entry points with

>0.35 ppb detection

3 water suppliers

Max: 4.4 ppb

Pilot Study –

Bethpage Water District

Study: UV+H2O2

Goals:– Treatment Capacity

– Economics

– Regulatory Approval

– Operator Familiarity

Variables

Set-Up and Sampling

Flow Diagram

Results

Pilot Study - Variables

Flow vs. Residence Time vs. UV Fluence

Pilot Study - Variables

[H2O2] Dosage

PROPORTIONAL TREATMENT CAPACITY

Pilot Study – Set-Up

Incorporating Flow vs. [H2O2] Dosage

Flow

[gpm]

1.5 ppm 3 ppm 6 ppm 12 ppm

15

30

60Increase [H2O2]

better removal

of contaminantsDecrease flow

better removal

of contaminants

During each

event, take

influent/effluent

samples

Pilot Study – Sampling and

Run MatrixRun No. TCE Conc. Diox Conc. Flow [gpm] [H2O2] UV Power

1 1510 60 15 0 0

2 1510 60 15 0 100

3 1510 60 15 12 0

4 5000 60 15 0 0

5 5000 60 15 0 100

6 5000 60 15 12 0

7 1510 60 15 1.5 100

8 1510 60 15 3 100

9 1510 60 15 6 100

10 1510 60 15 12 100

11 1510 60 30 1.5 100

12 1510 60 30 3 100

13 1510 60 30 6 100

14 1510 60 30 12 100

15 1510 60 60 1.5 100

16 1510 60 60 3 100

17 1510 60 60 6 100

18 1510 60 60 12 100

19 1510 60 60 1.5 60

20 1510 60 60 3 60

21 1510 60 60 6 60

22 1510 60 60 12 60

23 5000 60 15 1.5 100

24 5000 60 15 3 100

25 5000 60 15 6 100

26 5000 60 15 12 100

27 5000 60 30 1.5 100

28 5000 60 30 3 100

29 5000 60 30 6 100

30 5000 60 30 12 100

31 5000 60 60 1.5 100

32 5000 60 60 3 100

33 5000 60 60 6 100

34 5000 60 60 12 100

34 Runs

Spiked with additional TCE and 1,4-

Dioxane

Vary flow at 15, 30 and 60 gpm

Vary H2O2 from 1.5 ppm to 12 ppm

Four runs at 60% UV power

Influent and effluent samples for

each run

Lots of data!

Flow Diagram

Influent

Effluent

Flow Diagram - RPZ

RPZ

Device

Influent

from Well

No. 6-2

Flow Diagram - Chemical

Chemical

metering

pumps

Static

mixer

Chemical

injection

ports

Flow Diagram – Flow Metering

Flow

meter

Flow Diagram – AOP Reactor

AOP

Reactor

Flow Diagram – GAC Vessels

GAC

Vessels

Flow Diagram – Sampling

Points

Influent

Sampling

Effluent

Sampling

Post

GAC

Sampling

Pilot Study – Mixing Test

Mixing Test– Determine steady state

– Measure influent and effluent [H2O2]

Time [min] Influent [H2O2] Effluent [H2O2]

1 5.8 0.02

2 6.6 3.0

3 6.0 5.0

4 7.0 5.8

5 5.9 6.15

6 6.4 5.7

7 6.8 6.7

8 6.3 6.2

10 6.3 6.4

12 6.4 6.4

15 6.3 6.1

18 6.3 6.2

Pilot Study – Mixing Test

0

1

2

3

4

5

6

7

8

0 2 4 6 8 10 12 14 16 18 20

[H2O

2]

TIME [MIN]

15 GPM MIXING TESTInf Eff

Reactor has

reached

steady state

Pilot Study – VOC Data Results

Results as expected

Took 86 VOC Samples

Took 68 1,4-Dioxane

Samples

Took 36 IOC Samples

Took influent/effluent/post

GAC H2O2 samples

Cherry picked certain runs to

show trends

65 68 68 70

9.4

1.2 0.082 00

10

20

30

40

50

60

70

80

0 2 4 6 8 10 12 14

1,4

-DIO

XA

NE

[P

PB

]

H202 [PPM]

1,4-DIOXANE REMOVAL - 60 GPMInfluent Effluent

Pilot Study - Results

85.5%

98.2% 99.8% 99.9%

Increasing

[H2O2]

Pilot Study - Results

6963 65

0 2.59.4

0

10

20

30

40

50

60

70

80

0 10 20 30 40 50 60 70

1,4

-DIO

XA

NE

[P

PB

]

FLOW [GPM]

1,4-DIOXANE REMOVAL – 1.5PPMInfluent Effluent

Increasing

UV Fluence

99.9% 96.0% 85.5%

Pilot Study - Results

1,7001,600

1,700 1,700

280.00

52.00 10.00 0.750

200

400

600

800

1,000

1,200

1,400

1,600

1,800

0 2 4 6 8 10 12 14

TC

E[P

PB

]

H2O2 [PPM]

TCE REMOVAL – 60 GPMInfluent Effluent

83.5% 96.7% 99.4% 99.9%

Increasing

[H2O2]

Pilot Study - Results

1,5001,6001,600

0.55 3.10 52.000

200

400

600

800

1,000

1,200

1,400

1,600

1,800

0 10 20 30 40 50 60 70

TC

E[P

PB

]

FLOW [GPM]

TCE REMOVAL – 3PPMInfluent Effluent

96.5%99.8%99.9%

Increasing

UV Fluence

Regulatory Issues

Suggest to utilize 70%, 80% and 90% UV ballast power

Hydroxyl radical scavenging demand

Impacts of increase CO2

GAC utilization to quench H2O2

Disinfection by-products

Reaction intermediates

Thank-Yous

Bethpage Water District– Board of Commissioners– Supt. Mike Boufis– Pete Schimmel

TrojanUV– Terry Keep– Alan Royce

Pace Analytical– Stu Murrell– Melissa Watson

GA Fleet– Jamie Saxe

Colleagues– Rich Humann, P.E.– James Neri, P.E.– John Collins, P.E.– Paul Ponturo, P.E.

Questions?

I never learn anything talking. I only learn things when I ask

questions.