welcome to the october edition of the 2021 m&r seminar series

Welcome to the October Edition of the 2021 M&R Seminar Series

NOTES FOR SEMINAR ATTENDEES

• All attendees’ audio lines have been muted to minimize background noise.

• A question and answer session will follow the presentation.

• Please use the “Chat” feature to ask a question via text to “All Panelists.”

• The presentation slides will be posted on the MWRD website after the

seminar.

• This seminar has been approved by the ISPE for one PDH and approved

by the IEPA for one TCH. Certificates will only be issued to participants

who attend the entire presentation.

DR. LEON DOWNING, P.E.PRINCIPAL PROCESS ENGINEER/INNOVATION LEADER

BLACK & VEATCH

Dr. Leon Downing is a Principal Process Engineer and Innovation Leader with Black & Veatch. Dr. Downing provides technology leadership in support of Black & Veatch process engineering and applied research projects globally. Dr. Downing has spent the last 15 years working with process and operational changes focused on energy efficiency, nutrient removal, and resource recovery. He is currently serving as the Principal Investigator for Water Research Project 4975, which focuses on developing practical considerations for fermentative enhanced biological phosphorus removal. Dr. Downing is also a co‐Principal Investigator on Water Research Project 5083, where low energy biological nutrient removal processes are being investigated. Between these two research projects, design guidelines for the next generation of biological nutrient removal facilities will be developed for the industry.

© 2021 The Water Research Foundation. ALL RIGHTS RESERVED. No part of this presentation may be copied, reproduced, or otherwise utilized without permission.

Best Practices in Kinetic Rate Testing and Data Interpretation to Measure EBPR Health – A Water

Research Foundation Study

Leon Downing, PhD, PE

Patrick Dunlap, PE

Yueyun Tse, PhD, PE

April Gu, PhD, PE

© 2021 The Water Research Foundation. ALL RIGHTS RESERVED. 5

Agenda/Presentation

• EBPR health

• Rate testing to inform EBPR optimization

• RAS fermentation case study


WRF 4975 is focused on practical considerations for sidestream enhanced biological phosphorus removal

• 21 participating utilities globally

• $1.3 M research project value

• Identified as one of the top 10 Water Innovations for 2020

• Principal Investigator: Leon Downing, BV

• Co-PI: April Gu, University of Cornell

• Goals:

– Develop design criteria for the processes

– Identify operational tools for EBPR

– Recommend process modeling guidelines


EBPR Health


How do we better understand EBPR limitations?

“In biology, nothing is clear…Nature is anything but simple.” Richard Preston, Author of The Hot Zone


Evolution of Enhanced Biological Phosphorus Removal (EBPR)

• A two-step process of phosphorus release and uptake under alternating anaerobic and aerobic conditions.

• Phosphorus is released in the anaerobic zone to 25 to 40 mg/L, taken up in the aeration basin to as low as 0.05 mg/L soluble P.

9


Initial pilot testing by James Barnard indicated the importance of influent VFA and influent selector• Note orthophosphates profile through plant with high release in 2nd Anoxic zone

• Performance could not be replicated in laboratory

• Barnard postulated that organisms (PAO) should pass through anaerobic phase with low ORP and P release, which triggered EBPR

• Suggested Phoredox process by adding anaerobic zone up front

Barnard 100 m3/d pilot 1972


Proposed flow schematics were developed based on original thinking

These were followed by others such as UCT, JHB & Westbank


S2EBPR generates carbon from biomass to drive EBPR

• Deep ORP selects for a more diverse PAO ecology, which provides access to a wider range of COD fractions

12


Phosphate Accumulating Organisms (PAOS) are Focused on BOD Storage in Anaerobic Conditions

1313

PolyP

Anaerobic Conditions Aerobic Conditions

How do we better understand what is limiting PAO function?

PAO Cell

Glycogen

PolyPPHA

PO4PolyP

PAO Cell

Glycogen

PolyPPO4

O2VFA

PHA


Optimizing EBPR requires more than effluent monitoring

• Several different mechanisms for PAOs

• Effluent performance can suffer days after event that creates increased effluent

• Simple rate testing can be used for monitoring PAO health

• Modeling can be used to inform optimization efforts


Rate Testing to Understand PAO Health


Can we use rate testing to better understand PAO function?

Are we achieving PHA storage and phosphorus release?

Is phosphorus uptake and PHA breakdown occurring?

How much extra PHA is available at the end of aeration?

© 2021 The Water Research Foundation. ALL RIGHTS RESERVED. 17Black &Veatch 17

Release and uptake rate testing can be used as indicators of PAO population and activity

Sample from end of aeration basin, spike with acetate, measure phosphorus, then aerate to measure uptake rate


Indicator of PAO activity

Developed for WRF 4975 Design of S2EBPR

0

50

100

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200

250

0

2

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6

8

0 100 200 300 400

CO

D (

mg

/L)

Ort

ho

-P (

mg

/L)

Time (min)

Low PAO population

0

100

200

300

0

10

20

30

0 100 200 300 400

CO

D (

mg

/L)

Ort

ho

-P (

mg

/L)

Time (min)

Established EBPR

Ortho-P COD

0

100

200

300

0

0.5

1

1.5

2

0 100 200 300 400

CO

D (

mg

/L)

Ort

ho

-P (

mg

/L)

Time (min)

EBPR Startup

Ortho-P COD


Residual phosphorus uptake rate can be implemented to understand PHA reservoir for phosphorus uptake

Sample from end of aeration basin, spike with phosphorus, measure uptake rate


Indicator of how much PHA is stored

0

2

4

6

8

10

12

0 50 100 150 200 250

PO

43

- -P

(m

g/L

)

Time (min)

MLSS Residual Phosphorus Uptake 9/3/21


Residual phosphorus uptake rate testing can be an indicator of PHA limitation

0

0.0005

0.001

0.0015

0.002

0.0025

0.003

0.0035

0.004

0.0045

9:07 10:19 11:31 12:43 13:55 15:07

mgO

P/m

gTSS

2-June 9-Jun 16-Jun 23-Jun

0

0.5

1

1.5

2

2.5

June 2 June 9 June 16 June 23

Residual P Uptake Rate (mgP/mgTS-hr)

0

0.05

0.1

0.15

0.2

0.25

0.3

5/29 6/3 6/8 6/13 6/18 6/23 6/28

Effluent OP (mg/L)


Fermentation rate can help identify the availability of carbon in the RAS of the system

Sample from RAS prior to selector zones


Fermentation rate testing can identify P release and carbon release from RAS

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400

0

5

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0 20 40 60 80

CO

D (

mg/

L)

PO

43

- -P

(mg/

L)

Time (hr)

Ortho-P COD

Generate a RAS fermentation rate in mgCOD/gVSS-hr


Case Study


Wisconsin Rapids WWTP, Wisconsin Rapids, Wisconsin

Average flow: 3.5 mgdPeak day flow: 12 mgdFuture effluent P limit: 0.36 mg/LCurrent P Removal: PACl dosing


RAS fermentation testing design

RAS fermentation zone is returned to the aeration basins, not the MBBR

x

Cranberry wastewater feed to the fermentation zone


Overall performance has improved over time:RAS concentration and effluent

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0.2

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1

1.2

1.4

1.6

1.8

0

1000

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8000

9000

4/14/2021 5/4/2021 5/24/2021 6/13/2021 7/3/2021 7/23/2021 8/12/2021 9/1/2021 9/21/2021 10/11/2021

Effl

uen

t O

P (

mg/

L)

RA

S TS

S (m

g/L)

RAS TSS and Effluent Ortho-P

RAS TSS Effluent Ortho-P

PACl stopped


Overall performance has improved over time:carbon addition and effluent

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

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280

4/14/2021 5/4/2021 5/24/2021 6/13/2021 7/3/2021 7/23/2021 8/12/2021 9/1/2021 9/21/2021 10/11/2021

Effl

uen

t O

P (

mg/

L)

Car

bo

n A

dd

itio

n (

pp

d)

Carbon Addition and Effluent Ortho-P

Carbon Addition Effluent Ortho-P

PACl stopped

RAS Conc. Decrease


Can we think in terms of carbon needs for PAOs?

• System needs 420 to 570 ppd of carbon for EBPR

• RAS nitrate is 10 mg/L, which requires an additional 50 ppd of carbon

0

200

400

600

800

1000

1200

1400

1600

1800

5000 5500 6000 6500 7000 7500 8000 8500

sbC

OD

Pro

du

ctio

n (

pp

d)

RAS Concentration (mg/L)

1 2 3 4Ferm. Rate (mgCOD/gVSS-hr)

0

200

400

600

800

1000

1200

1400

1600

1800

20 30 40 50 60 70 80

sbC

OD

Req

uir

ed (

pp

d)

Phosphorus Load (ppd)

COD:P 11 COD:P 12 COD:P 13 COD:P 14

Average load during testing


RAS fermentation rate has been measured over time

• Average rate: ~1 mgCOD/gVSS-hr

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

24-May 13-Jun 3-Jul 23-Jul 12-Aug 1-Sep 21-Sep 11-Oct

Avg

Rat

e (m

gCO

D/g

VSS

-d)

RAS Fermentation

0

50

100

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350

400

0

5

10

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25

30

0 10 20 30 40 50 60 70 80

CO

D (

mg/

L)

Ort

ho

-P (

mg/

L)

Time (hr)

RAS Fermentation 9/7/21

Ortho-P COD


Can we think in terms of carbon needs for PAOs?

• Rate testing and mass balance would indicate an average shortage of ~235 ppd of carbon

0

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400

600

800

1000

1200

1400

1600

1800

5000 5500 6000 6500 7000 7500 8000 8500

sbC

OD

Pro

du

ctio

n (

pp

d)

RAS Concentration (mg/L)

1Ferm. Rate (mgCOD/gVSS-hr)

0

200

400

600

800

1000

1200

1400

1600

1800

20 30 40 50 60 70 80

sbC

OD

Req

uir

ed (

pp

d)

Phosphorus Load (ppd)

COD:P 11 COD:P 12 COD:P 13 COD:P 14

Average load during testingProduction: 340 ppd

Need: 575 ppd


Carbon balance is correlating to overall process performance

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1.4

1.6

-800

-600

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-200

0

200

400

5/15/2021 6/5/2021 6/26/2021 7/17/2021 8/7/2021 8/28/2021 9/18/2021 10/9/2021

Effl

uen

t O

P (

mg/

L)

sbC

OD

Def

fici

ency

(pp

d)

COD Defficiency (ppd) Effluent Ortho-P (mg/L)

Carbon addition began

PAClOff


Release and uptake can also be monitored over time to assess carbon efficiency

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18

0

1

2

3

4

5


PO

43

- -P

(m

g/L)

Rat

e (

mgP

/gV

SS-h

r)

P Release P Uptake Fermenter Ortho-P


Carbon source impact has also been investigated with bench-scale testing

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18

0 100 200 300 400

CO

D (

mg/

L)

PO

43

- -P

(m

g/L)

Time (min)

MLSS Phosphorus Release & Uptake Using Cranberry on 9/23/21

Ortho-P COD

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250

300

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16

18

0 100 200 300 400 500

CO

D (

mg/

L)

PO

43

- -P

(m

g/L)

Time (min)

MLSS Phosphorus Release & Uptake Using MicroC on 9/22/22

Ortho-P COD

0

50

100

150

200

250

300

0

2

4

6

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10

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16

18

0 100 200 300 400

CO

D (

mg/

L)

Ort

ho

-P (

mg/

L)

Time (min)

MLSS P Release and Uptake Using Acetate 8/18/21

Ortho-P COD


Is the RAS fermenter ecology adapted to cranberry juice (a.k.a. sugars)?

0.00

0.20

0.40

0.60

0.80

1.00

1.20

1.40

1.60

1.80

2.00

Cranberry Acetate MicroC

Ave

rage

Rel

ease

Rat

e (m

gP/g

VSS

-hr)


Carbon efficiency can also be examined over time

0

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100

120

140

160

0

1

2


CO

D:P

Du

rin

g R

elea

se

Effl

uen

t O

P (

mg/

L)

Effluent OP COD:P Ratio


Residual phosphorus uptake can also foreshadow carbon shortage

0

0.2

0.4

0.6

0.8

1

1.2

1.4

0.00

0.20

0.40

0.60

0.80

1.00

1.20

1.40

1.60

1.80

2.00

13-Jul 23-Jul 2-Aug 12-Aug 22-Aug 1-Sep 11-Sep 21-Sep 1-Oct

Effl

uen

t P

O4

3- -

P (

mg/

L)

Rat

e (

mgP

/gV

SS-h

r)

Rate Effluent Ortho-P


Summary


EBPR health should focus on assessing carboncycling in PAOs

3939

PolyP

Anaerobic Conditions Aerobic Conditions

How do we better understand what is limiting PAO function?

PAO Cell

Glycogen

PolyPPHA

PO4PolyP

PAO Cell

Glycogen

PolyPPO4

O2VFA

PHA


Knowledge of the Whole Plant COD Balance is critical for EBPR (especially S2EBPR)

40How many pounds of COD do we need for PHA charging & how do we get that COD?

PRIMARY CLARIFIER

PRIMARY SLUDGEFERMENTER

ACTIVATED SLUDGE

Influent rbCOD & VFA• Influent selector zone

AnaerobicAerobic

Secondary Clarifier

Carbon addition (via primary sludge fermentate or external source)

• Controlled dosing to sidestream tank

RAS FERMENTER

COD available from VSS in RAS• Sufficient relative to influent P

• Impacted by influent characteristics, RAS nitrate, aerobic SRT

• Ability to produce 1 to 4 mgCOD/gVSS-hr

3

1

2


Relatively simple rate testing can providecritical carbon balance information

• Simple apparatus

• Chemical needs: carbon source and orthophosphate

• Analytics: COD, phosphorus, nitrate

• Largest challenge: sample filtration

© 2021 The Water Research Foundation. ALL RIGHTS RESERVED. No part of this presentation may be copied, reproduced, or otherwise utilized without permission.

Thank you

Comments or questions, please contact:

Leon Downing: [email protected]

For more information, visit www.waterrf.org

mailto:[email protected]

http://www.waterrf.org/

welcome to the october edition of the 2021 m&r seminar series

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