Pilot Testing Results for a Direct-to- Distribution DPR...

© Arcadis 2016

Imagine the result

Pilot Testing Results for a Direct-to-

Distribution DPR Treatment Train

Presenter: Daniel Olson, Arcadis

Texas WateReuse – June 30, 2016

Background

• El Paso, TX

• Population: 600,000+

• Semi-arid climate typical of Southwest U.S.

• Rio Grande over-allocated in drought year

• Non-Potable Reuse since 1956

• Indirect Potable Reuse since 1985

• Now embarking on DPR

The River Groundwater Desalination

Water

ReuseConservation

Future

Resources1

1 Future resources will include importation from water rights landholdings and from other identified sources

Current Reservoir Levels

June 2, 1994

July 8, 2013

Sources: NASA

“Elephant Butte Reservoir is

17.7% full as of April 20, 2016”

--- Water Data for Texas

Feasibility Study (2012)

PlanningPilot

TestingDesign Build

Implementing Potable Reuse for El Paso

Feasibility Study

Planning (2014)

Pilot Testing

Design Build


Water Quality Goals• Address regulatory criteria and public concerns for this DPR project• Meet all primary water quality standards• Provide multiple barriers for pathogens• Provide diverse treatment for chemical micro-constituents• Meet EPWU specific goals

Feasibility Study

PlanningPilot

Testing (2015)

Design Build


Pilot Testing Overview

Core Treatment Train

Membrane Filtration

• Pall MF

• Evoqua UF

Membrane Desalination

• Hydranautics ESPA2

• Dow NF90

• Hydranautics ESNA1

UV-Peroxide Advanced Oxidation

Granular Activated Carbon

• Catalytic Bituminous (Calgon)

• Catalytic Coconut Shell (Evoqua)

• Non-catalytic Bituminous (Calgon)

Source Water: Bustamante WWTP

ActivatedSludgePrimary Settling Secondary Settling

Return Activated Sludge

Cl2

Discharge to Riverside Canal

Pre-Aeration

Screening/Grit Removal

10 MGD

To AWPF

NF/RO

Concentrate

Cl2MF/UF

Backwash

Disinfection

ClearwellGAC for H2O2

Quenching

UV AOP

Secondary Clarifier Effluent

NF/RO

Concentrate

Cl2MF/UF

Backwash

Disinfection


Quenching

UV AOP


Denitrification Filters

NF/RO


MF/UF


Quenching

UV AOP

O3

Ozone Cl2 Disinfection

Pre-treatment Results

• Denitrification Filters

• Effluent water quality tendency to foul MF/UF

• Ultimately not necessary for NOx removal

• Higher cost to operate w/ Denit. Filters

• Low-Dose Ozonation

• No observed improvement to MF/UF flux or TMP

• Increased disinfection byproducts (bromate, NDMA)

• Increased AOC, potentially leading to biofouling

• Higher cost to operate with Ozone

Membrane Filtration

© Arcadis 2016

Pall MF: Stage 2a (35 gfd)

Maximum TMP

© Arcadis 2016

Evoqua UF: Stage 2a (35 gfd)

Maximum TMP

• Both Pall and Evoqua systems successfully completed Stage 1-2-3 testing without pretreatment (e.g., ozone or denitrification filters)

• Operation at conservative fluxes

• No “irreversible” fouling observed

– Successful confirmation via Stage 3 testing

– Clean water flux testing results: consistently restored to baseline

• All daily LRVs exceeded 4.0

Membrane Filtration: Key Points

Nanofiltration / Reverse Osmosis

• 4”-diameter membrane elements:

– ESPA2-LD

– NF90-400/34i

– ESNA1-LF2-LD

• 2:1 array

• Recovery: 80%

• Flux: 11.7 gfd

• Pretreatment: acid + scale inhibitor

Removed from pilot testing, due to poor rejection of nitrate and nitrite

NF/RO System Overview

Parameter Units

NF/RO

Feed GoalESPA2-LD

(RO)

NF90

(Tight NF)

ESNA1

(Loose NF)

Chloride mg/L 285 300 24 7.2 61

Nitrate mg/L as N 12.0 TBD 2.4 1.3 5.1

Nitrite mg/L as N 1.06 TBD 0.04 0.06 0.9

Sulfate mg/L 274 300 7.6 0.9 5.0

TDS mg/L 1,075 900 84 37 174

TOC mg/L 7.51 TBD 0.5 0.5 0.9

Data are average valuesND: Not DetectedTBD: To Be Determined

RO and Tight NF demonstrated 70-90%

rejection of nitrate and nitrite

RO and Tight NF demonstrated ability to meet nitrate and nitrite MCLs

• Both ESPA2 and NF90 membrane elements can achieve objectives for removal of dissolved solids (and constituent components)

• ESPA2 average permeate concentrations shown are skewed higher by data collected with damaged membranes prior to replacement

• NF90 nitrate rejection was much better than anticipated based on modeling projections

• Very low permeate TOC will help reduce DBP formation

NF/RO: Key Points

UV/H2O2 Advanced Oxidation

• Low-Pressure High Output (LPHO) reactor

• Peroxide dose: 4 mg/L

• Treatment Targets:

• Photolysis: 1.2-log reduction of NDMA

• Oxidation: 0.5-log reduction of 1,4-dioxane

• NF/RO permeates treated sequentially

• Testing for CECs

UV AOP System Overview

CEC Removal ResultsChemical Name Units

Detection

Limit

UV AOP

Influent

UV AOP

Effluent % Removal

4-nonylphenol ng/L 100 660 230 65%

4-tert-Octylphenol ng/L 50 400 120 70%

Acesulfame-K ng/L 20 150 ND -

Atenolol ng/L 5 8 ND -

Carbamazepine ng/L 5 8.9 ND -

DEET ng/L 10 13 ND -

Diclofenac ng/L 5 6.2 ND -

Iohexal ng/L 10 28 ND -

Iopromide ng/L 5 6.9 ND -

Sucralose ng/L 100 1400 220 84%

TCEP ng/L 10 19 ND -

Triclocarban ng/L 5 33 ND -

Triclosan ng/L 10 55 ND -

RO Permeate, October 20th

CEC Removal ResultsChemical Name Units

Detection

Limit

UV AOP

Influent

UV AOP

Effluent % Removal

4-nonylphenol ng/L 100 340 190 44%

4-tert-Octylphenol ng/L 50 ND ND -

Acesulfame-K ng/L 20 ND ND -

Atenolol ng/L 5 ND ND -

Carbamazepine ng/L 5 ND ND -

DEET ng/L 10 11 ND -

Diclofenac ng/L 5 ND ND -

Iohexal ng/L 10 ND ND -

Iopromide ng/L 5 ND ND -

Sucralose ng/L 100 260 ND -

TCEP ng/L 10 ND ND -

Triclocarban ng/L 5 ND ND -

Triclosan ng/L 10 ND ND -

NF (Tight) Permeate, December 16th

1,4-dioxane not detected in influent; rely on surrogate compounds

Chemical Name

Hydroxyl Radical Rate Constant

(L/mole·sec) Pilot % Removal

1,4-dioxane 2.5 - 3.1 × 109 >69% (Target)

4-nonylphenol 7.6 × 108 - 1.3 × 109 65%

4-tert-Octylphenol (4.2±1.2) × 109 70%

Acesulfame-K (3.80 ± 0.27) × 109 >87%

Sucralose (1.50 ± 0.01) × 109 84%

Bench-Scale Testing Confirmed Ability to Reduce NDMA

Granular Activated Carbon

GAC for Peroxide Quenching

0

1

2

3

4

5

6

0 5,000 10,000 15,000 20,000 25,000 30,000 35,000 40,000 45,000

H2

O2

Co

nc

en

tra

tio

n (

mg

/L)

Bed Volumes

Hydrogen Peroxide Quenching

UV AOP Effluent GAC #1 - Catalytic Re-Agg Bit

GAC #2 - Catalytic Coconut Shell GAC #3 - Re-Agg Bit

Peroxide Quenching Profiles

Disinfection

Disinfection Byproducts

0

10

20

30

40

50

60

6/10/15 7/30/15 9/18/15 11/7/15 12/27/15

DB

P C

on

ce

ntr

ati

on

(µ

g/L

)

7-Day SDS Results - UV AOP Effluent

HAA5

HAA5 Detection Limit

TTHM

TTHM Detection Limit

Disinfection Byproducts

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

4.50

5.00

0 5,000 10,000 15,000 20,000 25,000 30,000 35,000 40,000 45,000

DB

P C

on

ce

ntr

ati

on

(µ

g/L

)

Bed Volumes

GAC Effluent - SDS Results

TTHM, Catalytic Re-Agg Bit

TTHM, Catalytic Coconut Shell

TTHM, Re-Agg Bit

TTHM Detection Limit

HAA5, Catalytic Re-Agg Bit

HAA5, Catalytic Coconut Shell

HAA5, Re-Agg Bit

HAA5 Detection Limit

Microbial Results

Cryptosporidium

0.100

1.000

10.000

100.000

1,000.000

SC Effluent

n=20

Denit. Eff.

n=5

Post Ozone

n=5

MF/UF Inf.

n=16

Evoqua Filt.

n=16

Pall Filt.

n=16

Pre AS &

Acid

n=9

ESPA2-LD

Perm.

n=6

NF90

Perm.

n=8

UV AOP

Inf.

n=8

UV AOP

Eff.

n=9

Cry

pto

spo

rid

ium

(O

ocy

sts/

L)

Giardia

0.100

1.000

10.000

100.000

1,000.000

SC Effluent

n=20

Denit. Eff.

n=5

Post Ozone

n=5

MF/UF Inf.

n=16

Evoqua Filt.

n=16

Pall Filt.

n=16

Pre AS &

Acid

n=9

ESPA2-LD

Perm.

n=6

NF90

Perm.

n=8

UV AOP

Inf.

n=8

UV AOP

Eff.

n=9

Gia

rdia

(C

yst

s/L)

Total Culturable Virus (MPN/L)

DateSecondary Clarifier

EffluentUV AOP Effluent

6/10/2015 0.25 ND

7/8/2015 0.46 ND

8/6/2015 0.403 ND

9/14/2015 0.09 ND

10/7/2015 0.575 ND

10/28/2015 0.48 ND

11/30/2015 0.4 ND

12/28/2015 0.299 ND

Pathogen Removal Requirements and Preliminary Results

Unit Process

Anticipated Log Removal / Inactivation Credits

Crypto Giardia Viruses

Pretreatment 0 0 0

MF/UF 4 4 0

NF/RO 0 0 0

UV AOP 4-6 4-6 4-6

GAC 0 0 0

Cl2 0 3 4

Total 8-10 11-13 8-10

Projected Requirement 7 8 8

Anticipated removal requirements

achieved through AWPF unit processes

without WWTP chlorination

Corrosion Control

Pipe Loop Testing / Corrosion Control• Assessed corrosivity of

NF/RO permeates

• Galvanized steel and copper pipes harvested from distribution system

• Monitored iron, copper, lead

• Testing conditions included stabilization by:

• pH adjustment

• Alkalinity adjustment (calcite contactor)

• Corrosion inhibitor addition

• Groundwater blending

Testing demonstrated successful stabilization methods

• Purified water metals concentrations were lower than baseline tap supply in pipe loops

• Post-treatment stabilization resulted in lower metals concentrations

• Preliminary approach for full-scale treatment:

• Finished water quality targets:

– CCPP between 4-10 mg/L as CaCO3

– LSI > 0

– pH between 7.5-8.0

• Multiple options for stabilization No notable challenges for

introducing purified water

into the distribution system

Online Monitoring

Acetone Spike – TOC Analyzer

0.1

1

10

0.1 1 10

NO

3 b

y C

he

msc

an

(m

g/L

as

N)

NO3 by IC (mg/L as N) UTEP

Comparison of online nitrate analyses and

laboratory analyses

Sec Clarifier Effluent

ESPA 2 permeate

NF 90 Permeate

ChemScan Analyzer Accuracy Check

Pilot Logistics

Pilot InvestmentApproximately $4 million spent on pilot phase

• Pilot plant construction & decommissioning

• Equipment purchase & rentals

• Labor & operations

• Sampling, shipping & lab analyses

• Online monitoring

• Corrosion pipe loop testing

• Public outreach campaign

• Data analysis

• Regulatory coordination & report preparation

• EPWU staff time

• NWRI Independent Advisory Panel

• UTEP student involvement

• Project management

Independent Advisory Panel

Public OutreachCampaign

Regulatory Coordination

EPWU Resources

UTEP Involvement

• El Paso Water Utilities:– John Balliew

– Alan Shubert

– Fernie Rico

– Carlos Dominguez

– Aide Zamarron

• Arcadis:– Brent Alspach

– James Collins

– Chelsea Francis

– George Maseeh

– Priscilla Sandoval

– Sanaan Villalobos

Acknowledgements

• UTEP:– Dr. Shane Walker

– Cesar Alvarez

– Seye Owoseni

– Clara Borrego

– Troy Svede

• NWRI Advisory Panel– Jeff Mosher

– Dr. Paul Westerhoff

– Dr. Desmond Lawler

– Dr. Channah Rock

– Steve Walden

– Eleanor Torres

13 July 2016 52

Thank You

o 915 747 3924

c 201 390 1469

e [email protected]

DANIEL OLSON

Sr. Engineer / Project Manager

Pilot Testing Results for a Direct-to- Distribution DPR...

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