biological phosphorus removal case studies - awma-ums

Biological Phosphorus Removal Case Studies

2014 Conference on the Environment

Leon Downing, PhD, PE Bill Marten, PE, BCEE

Nathan Cassity, PE, BCEE

Agenda

Biological phosphorus removal review Case studies Characterization impacts BNR configurations Operational tools

Slide Number 2

biological phosphorus removal

Bio-P

Enhanced Biological Phosphorus Removal (EBPR)

Electron Donor

(Volatile Fatty Acids)

Slide Number 4

Bio-P

Enhanced Biological Phosphorus Removal

Electron Donor


Slide Number 5

Bio-P


Electron Donor


Slide Number 6

Bio-P


Electron Donor


Electron Acceptor #1

Oxygen

(Full bodied lager)

Slide Number 7

Bio-P


Electron Donor



Oxygen

(Full bodied lager)


Nitrate

(Light beer)

Slide Number 8

Bio-P


Electron Donor



Oxygen

(Full bodied lager)


Nitrate

(Light beer)


EBPR

(Water)

Slide Number 9

Bio-P


Electron Donor



Oxygen

(Full bodied lager)


Nitrate

(Light beer)


EBPR

(Water)

Slide Number 10

Bio-P


Electron Donor



Oxygen

(Full bodied lager)


Nitrate

(Light beer)


EBPR

(Water)

EBPR: Lowest energy Limit#1 and #2 at front of basin

Slide Number 11

Bio-P


Electron Donor



Oxygen

(Full bodied lager)


Nitrate

(Light beer)


EBPR

(Water)

EBPR: Lowest energy Limit#1 and #2 at front of basin

MIXERS

DENITRIFICATION

Slide Number 12

Configurations

Slide Number 13

RAS IMLR 1

EBPR Denit. Nitrification

RAS

IMLR 2


RAS

IMLR 1


RAS

IMLR 1


Denit.

IMLR 1

Denit.

UCT’

MUCT

5 Stage Bardenpho

A2O

Optimal P removal

Optimal N removal

Both

Things to Consider

Wastewater characteristics BNR configuration Approaches and goals

Operational “tricks”

Slide Number 14

wastewater characteristics

Wastewater Characteristics

All BOD is not created equally

Slide Number 16


All BOD is not created equally

VFAs (and rbCOD):

Key for Bio-P

Slide Number 17


Plant 1: Beloit, WI

Small collection system

High food waste content

rbCOD:tCOD: 0.3

Slide Number 18


Plant 1: Beloit, WI



rbCOD:tCOD: 0.3

Plant 2: TRA CRWS

Large collection system

Warm weather

rbCOD:tCOD: 0.25

Slide Number 19


Plant 1: Beloit, WI



rbCOD:tCOD: 0.3

Plant 2: TRA CRWS


Warm weather

rbCOD:tCOD: 0.25

Plant 3: Medford, WI


Limited industry

rbCOD:tCOD: 0.1 Slide Number 20


Plant 1: Beloit, WI



rbCOD:tCOD: 0.3

Plant 2: TRA CRWS


Warm weather

rbCOD:tCOD: 0.25

Plant 3: Medford, WI


Limited industry

rbCOD:tCOD: 0.1

Average influent BOD:

250 to 300 mg/L

Slide Number 21


A/O Process

Requirements: baffle wall, mixers

Slide Number 22


0

0.5

1

1.5

2

2.5

3

3.5

0.1 0.2 0.3

Effluent TP

(mg/L)

rbCOD/tCOD (higher value = more "easy" BOD)

Plant 3 Plant 2 Plant 1

Plenty of soluble “food:” Enough to go around: Process is simplified

Slide Number 23

bnr configurations

Sun Prairie, Wisconsin

Configuration

SP dry weather

SP dewatering

SP wet weather

0.0

5.0

10.0

15.0

20.0

25.0

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

rbCO

D/P

ratio

Fraction of rbCOD that is VFA

WHY SOME BIO-P PLANTS WORK BETTER THAN OTHERS

Standard curve (Barnard et al, WEFTEC 2005)

Slide Number 26

Configuration

RAS

Internal Recycle

PE

AnaerobicZones

Anoxic Zones

Aerobic Zones

Modified VIP/UCT Bio-P Process

Slide Number 27

Performance 1125 Days without Ferric Addition

14 Days with Ferric Addition

0.0

0.5

1.0

1.5

Target Effluent TP, mg/L Average Effluent TP, mg/L

Zero Permit

Violations

Slide Number 28

Janesville, WI

Slide Number 29

Configuration

SP dry weather

SP dewatering

SP wet weather

0.0

5.0

10.0

15.0

20.0

25.0

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

rbCO

D/P

ratio

Fraction of rbCOD that is VFA

WHY SOME BIO-P PLANTS WORK BETTER THAN OTHERS

Standard curve (Barnard et al, WEFTEC 2005)

Janesville

Slide Number 30

Biological Nutrient Removal Design

PE RAS

Anaerobic

Aerobic

Anaerobic

Anaerobic

Aerobic Aerobic

Anoxic

Anoxic

Swing

Swing

Anoxic

Anoxic

Swing

Anoxic

Anoxic

Swing

Fermenters

Slide Number 31

Biological Nutrient Removal Design

Fermentation incorporated Offset BOD:P issue High level of N and P removal

Fermenters Overflow (VFAs)

Primary sludge

Fermented primary sludge

Slide Number 32

Startup and Operation

Fermenter overflow Flow of 0.9 MGD 7% of forward flow Currently generating

1000 lbs/day VFA

Date Volatile Acids (mg/L)

01/03/12 100 01/24/12 87 02/14/12 125 02/22/12 115 02/28/12 216 03/07/12 218 03/14/12 183 03/14/12 163 03/21/12 60 03/27/12 118 04/04/12 72 04/09/12 150 04/18/12 121 04/24/12 105 05/04/12 139 Average 132

Slide Number 33

Performance

Slide Number 34

0.0

0.1

0.2

0.3

0.4

0.5

08/24/13 08/31/13 09/07/13 09/14/13 09/21/13 09/28/13 10/05/13 10/12/13

Phos

phor

us C

once

ntra

tion

(mg/

L)

operational “tricks”

Do your mixers need to run all the time?

36

July 2013: power out in aeration basin (mixers off)

Mixing still observed

Do we really need 20 total horsepower of mixing in the

selector zone?

October 2013:

Manual cycling of mixers every 2 hours

Slide Number 36

Mixers Alternated On/Off

-350

-300

-250

-200

-150

-100

-50

0

10/8/13 0:00 10/13/13 0:00 10/18/13 0:00 10/23/13 0:00 10/28/13 0:00ORP (mV)

ORPNorth MixerSouth Mixer

Mixer On

Mixer Off

Mixers alternated

on/off

Increased ORP variability, still

anaerobic

Slide Number 37

Mixers On/Off Sheboygan WWTP Sheboygan, Wisconsin

-600

-500

-400

-300

-200

-100

0

1:00 2:00 3:00 4:00 5:00 6:00

ORP (mv)

Time (hours)

Mixers: cycle on/off every two hours

ORP drop

Mixed liquor fermentation?

Slide Number 38

Anaerobic selector zone

Low DO Operation

DO = 2 mg/L DO = 2 mg/L DO = 3 mg/L

Conventional

Slide Number 39

Low DO Operation

DO = 2 mg/L DO = 2 mg/L DO = 3 mg/L

Conventional

Low DO

DO = 0.75 mg/L DO = 0.75 mg/L DO = 1.5 mg/L

Slide Number 40

Trinity River Authority CRWS Treatment Plant

189 mgd average day flow capacity

Modified one of twelve aeration basins to BNR in 2012

AO process, relies on simultaneous nitrification and denitrification (SND)

Slide Number 41

Nitrogen Removal

0

5

10

15

20

25

30

35

7/1/2012 9/30/2012 12/30/2012 3/31/2013

Nitrogen Removed

(mg/L)

Conv. DO Low DO (0.75 – 1 mg/L)

Slide Number 42

Phosphorus Removal

0

0.5

1

1.5

2

2.5

3

No Selector Selector + Conventional DO Selector + Low DO

Average Effluent

TP (mg/L)

Slide Number 43

takeaways…

Takeaways

Wastewater characterization Not all BOD is created equal BOD variability is a key consideration

Configuration Select the configuration to meet your goals

Operational “tricks” to consider Mixer cycling Low Do operation

Slide Number 45

Questions? Leon Downing, PhD, PE Donohue & Associates 920.889.9291 [email protected]

biological phosphorus removal case studies - awma-ums

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