biological phosphorus removal technology - wwoa phosphorus...•biological phosphorus removal is a...

Biological Phosphorus

Removal Technology

Presented by: Eugene Laschinger, P.E.

Overview

• What is phosphorus and why do we care?

• How can you remove phosphorus?

• Biological phosphorus removal

• Biological phosphorus removal facilities

▫ Tomah, WI

▫ Dane-Iowa, WI

▫ Cross Plains, WI

▫ Reedsburg, WI

▫ Rhinelander, WI

Phosphorus

Phosphorus Regulation

• Technology based effluent limits ▫ Typical = 1.0 mg/L

▫ Alternative phosphorus limits (APL) Biological – maximum 2.0 mg/L

Economics - variance

• Water quality based effluent limits ▫ Based upon target concentration in receiving water

▫ Total Maximum Daily Load (TMDL)

▫ Can be as low as 0.100 - 0.075 mg/L for streams and 0.040 – 0.015 mg/L for lakes

Chemical Phosphorus Removal

• Coagulant ▫ Alum ▫ Ferric Chloride ▫ Ferric Sulfate ▫ Poly aluminum chloride (PAC)

• Advantages ▫ Simple ▫ Lower capital cost (sometimes)

• Disadvantages ▫ Sludge production ▫ Operational costs ▫ Chemical handling ▫ Consumes alkalinity

Biological Phosphorus Removal (BPR)

• Create an environment to select for organisms that will store phosphorus

• Requirements ▫ Readily biodegradable BOD in the form of volatile fatty

acids ▫ Phosphorus ▫ Cycling between anaerobic and aerobic environments

• Advantages ▫ Low operational costs ▫ Improved treatment performance

• Disadvantages ▫ Capital cost ▫ More complicated treatment

BPR Microbiology

• Phosphorus accumulating organisms (PAOs)

▫ Store excess phosphorus inside cells

▫ Release phosphorus for energy in anaerobic environment

▫ Take in phosphorus in aerobic environment

• Identifying PAOs and biological phosphorus removal

▫ Anaerobic batch testing

▫ Staining techniques

▫ DAPI

▫ Florescence In-Situ Hybridization (FISH)

▫ DNA sequencing

Typical Biological Removal Configuration

Influent Considerations

• BOD and phosphorus required for biological

phosphorus removal to work

• BOD should be in readily biodegradable form

• Nitrate inhibits biological phosphorus removal

▫ High influent ammonia will be converted to nitrate if

nitrification occurs

• Frequency and quantity of inflow and infiltration

(I&I)

Primary Clarifier

• Removal of non-biodegradable or difficult to degrade components

• Use as ACTIVATED primary for production of VFA’s ▫ Hold sludge blanket

▫ Recirculate sludge - elutriation

Activated Primary Clarifier

Selector Basins

• Anaerobic environment

• VFA’s formed through

fermentation

• Organisms take in VFA’s

and store VFA’s as PHB

• Phosphorus released to

give PAO energy

Anaerobic Environment

VOLATILE FATTY ACIDS

(INFLUENT BOD)

PHOSPHATE

PHOSPHORUS

ACCUMULATING ORGANISM

PHB POLY-P

ENERGY

Aeration Basins

• Stored PHB is consumed (BOD)

• Influent and released phosphorus is taken up to provide energy for future reactions

• Micro organisms grow and reproduce

• Higher phosphorus content in cells (>4% vs. 1% - 2%)

PHB

Aerobic Environment

OXYGEN

OR

NITRATE

PHOSPHATE

(INFLUENT AND RELEASED)

PHOSPHORUS

ACCUMULATING ORGANISMS

POLY-P

ENERGY

CO2

OR

N2 GAS

PHB POLY-P

GROWTH

Final Clarifiers, RAS, and WAS

• Phosphorus laden

organisms settle

• Rapid sludge removal

(avoid secondary

release)

• Sludge wasting

removes organisms

and phosphorus from

system

Waste Activated Sludge

PHOSPHORUS

ACCUMULATING ORGANISMS

POLY-P

POLY-P

POLY-P

ORGANISMS

RECYCLED TO

SELECTOR

BASIN

“P” REMOVED FROM

SYSTEM IN WASTE

SLUDGE

SLUDGE

WASTING

Special Considerations for BPR

• Secondary release – selector basins and clarifiers

• Nitrates – RAS

• Recycle streams – especially with anaerobic digestion

• ORP and DO control

Tomah, WI WWTP

• Design Conditions

▫ Design Flow 2.3 MGD

▫ Peak Hourly Flow 8.0 MGD

▫ BOD 4,500 lbs/day

▫ TSS 4,750 lbs/day

▫ TKN 540 lbs/day

▫ Phosphorus 190 lbs/day

• Unique features

▫ High influent phosphorus load – Concentration 10 mg/l to 20 mg/l

▫ Difficult chemical treatment

Tomah, WI WWTP

Tomah Start-Up (February – May, 2000)

Fermenter

(Off Line)

Pre-Anoxic

Basin

(Off Line)

Anaerobic

Basin #1

Anaerobic

Basin #2 Oxidation

Ditch

Raw

Wastewater

RAS Flow

Tomah February – May 2000 Results

0

15

30

45

60

75

Dat

e

2/7/

00

2/14

/00

2/21

/00

2/28

/00

3/6/

00

3/13

/00

3/20

/00

3/27

/00

4/3/

00

4/10

/00

4/17

/00

4/24

/00

5/1/

00

5/8/

00

5/15

/00

5/22

/00

5/29

/00

Date

(Note: May 18 Influent P 184.29 mg/l, Effluent P 102.76 mg/l)

Infl

uen

t P

ho

sp

ho

rus C

on

cen

trati

on

, m

g/l

0

6

12

18

24

30

Eff

luen

t P

ho

sp

ho

rus C

on

cen

trati

on

, m

g/l

Inf P

Eff P

Tomah Start-Up (June – July 2000)

Fermenter

Pre-Anoxic

Basin

(Off Line)

Anaerobic

Basin #1

Anaerobic

Basin #2 Oxidation

Ditch

Raw

Wastewater

RAS Flow

Tomah June – July 2000 Results

0

4

8

12

16

20

24

28

Date 6/7/00 6/14/00 6/21/00 6/28/00 7/5/00 7/12/00 7/19/00 7/26/00Date

Infl

uen

t P

ho

sp

ho

rus C

on

cen

trati

on

, m

g/l

0

1

2

3

4

5

6

7

Eff

luen

t P

ho

sp

ho

rus C

on

cen

trati

on

, m

g/l

Inf P

Eff P

Tomah Start-Up (August – Dec. 2000)

Fermenter

Pre-Anoxic

Basin

(Off Line)

Anaerobic

Basin #1

Anaerobic

Basin #2 Oxidation

Ditch

Raw

Wastewater

RAS Flow

Tomah June – July 2000 Results

0

5

10

15

20

25

30

35

Dat

e

8/7/

00

8/14

/00

8/21

/00

8/28

/00

9/4/

00

9/11

/00

9/18

/00

9/25

/00

10/2

/00

10/9

/00

10/1

6/00

10/2

3/00

10/3

0/00

11/6

/00

11/1

3/00

11/2

0/00

11/2

7/00

12/4

/00

12/1

1/00

12/1

8/00

12/2

5/00

Date

Infl

uen

t P

ho

sp

ho

rus C

on

cen

trati

on

, m

g/l

0

1

2

3

4

5

6

7

Eff

luen

t P

ho

sp

ho

rus C

on

cen

trati

on

, m

g/l

Inf P

Eff P

Tomah Operation (2012 - 2013)

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

Eff

luen

t P

ho

sph

oru

s C

on

cen

tra

tion

, m

g/L

Date

Tomah WWTF

Effluent Phosphorus

Concentration

Current Monthly Permit Limit

• Effluent Results 2012

▫ BOD/SS < 5 mg/L

▫ Ammonia < 0.5 mg/L

▫ Phosphorus < 0.3 mg/L

• No chemical usage for

“P” removal

• No control on recycle

streaming

Tomah Plant Operating Results

Dane-Iowa WWTP

• Design Flow 0.693 MGD

• Peak Hourly 1.981 MGD

• BOD 1,369 lbs/day

• TSS 1,501 lbs/day

• TKN 230 lbs/day

• Phosphorus 37 lbs/day

Dane-Iowa WWTP

Dane-Iowa Performance

0.0

0.5

1.0

1.5

2.0

2.5

Eff

luen

t P

ho

sph

oru

s C

on

cen

tra

tion

, m

g/L

Date

Dane-Iowa WWTF

Monthly Average Effluent

Phosphorus Concentration


Cross Plains, WI WWTP

• Design Flow 0.593 mgd

• Peak Hourly 2.27 mgd



• TKN 155 lbs/day


Cross Plains, WI WWTP

Cross Plains Performance

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

Eff

luen

t P

ho

sph

oru

s C

on

cen

tra

tion

, m

g/L

Date

Effluent Phosphorus Concentration


Reedsburg, WI WWTP

• Design Flow 2.646 MGD

• Peak Flow 7.914 MGD



• TKN 687 lbs/day


Reedsburg, WI WWTP

Reedsburg Performance

0.00

1.00

2.00

3.00

4.00

5.00

6.00

Eff

luen

t P

ho

sph

oru

s C

on

cen

tra

tion

, m

g/L

Date



Rhinelander, WI WWTP

• Design Flow 2.153 mgd

• Peak Hourly Flow 7.894 mgd



• TKN 423 lbs/day


Rhinelander, WI WWTP

Rhinelander Performance

0

0.5

1

1.5

2

2.5

3

3.5

4

Eff

luen

t P

ho

sph

oru

s C

on

cen

tra

tion

, m

g/L

Date


Rhinelander Challenges

• Anaerobic digester recycle streams

• Carbon – need to feed Bio P and anaerobic digester

• Batching for digester

• More complex controls

Dodgeville, WI WWTP






▫ NH3 380 lbs/day


▫ Typical Discharge .5 mg/L to .7 mg/L with chemical

Dodgeville, WI WWTP

Dodgeville, WI WWTP

• WWTP Operational Modifications

▫ Revised Process Flow – Influent Flow Diverted to Tank #1

▫ Timers Added to Mixers – Operated 20 Minutes/Hour

• WWTP Improvements

▫ Effluent Improvements

Effluent P reduced to 0.30 PPM annual average

▫ Chemical Addition Reduced

Previous Chemical Addition Seasonally

Reduced Chemical Consumption – Saving >$35,000 per Year

Marshfield, WI WWTP






▫ TKN 1,550 lbs/day


• Unique features

▫ High peak flow

▫ Designed for only chemical phosphorus removal

Marshfield, WI WWTP

Marshfield, WI WWTP

• Plant Performance Prior to Changes in Operation

▫ Generally BOD/SS Very Good

▫ Required 200 gpd of Ferric Chloride

▫ Effluent Phosphorus .7 mg/L to .9 mg/L

• WWTP Operational Modifications

▫ Operate Two Ditches in Series

▫ First Ditch Operated with Low DO/Anoxic

Marshfield, WI WWTP

• WWTP Improvements ▫ Effluent Improvements

Effluent P reduced from 0.90 mg/L to 0.1 – 0.2 mg/L

▫ Chemical Addition Reduced Chemical Addition Reduced to 25 gpd

Projected Annual Savings of $95,000

▫ Sludge Dewatering Reduce Polymer Addition 40% to 50%

▫ Potential Future Improvement Update Controls

Replace Aerators to Lower Power and Improve Mixing

Summary

• Biological phosphorus removal is a reliable

alternative for phosphorus removal down 0.2mg/L to

0.5 mg/L or below

• Designs must incorporate flexibility to ensure

systems can be optimized

• Treatment arrangements should be suited for the

specific WWTP

• Process control allows ease of operation

Questions / Comments

biological phosphorus removal technology - wwoa phosphorus...•biological phosphorus removal is a...

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