How Much is E N N OUGH? OUGH? How Much is E Optimizing - - PowerPoint PPT Presentation

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How Much is E N N OUGH? OUGH? How Much is E Optimizing Nitrification and Denitrification Denitrification Optimizing Nitrification and at the Water Reclamation Plants at the Water Reclamation Plants Joe Chang, Water

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SLIDE 1

How Much is E How Much is E “ “N N” ”OUGH? OUGH?

Optimizing Nitrification and Optimizing Nitrification and Denitrification Denitrification at the Water Reclamation Plants at the Water Reclamation Plants

Joe Chang, Water Reclamation Plants

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SLIDE 2

LA County Sanitation Districts: Background Information LA County Sanitation Districts: LA County Sanitation Districts: Background Information Background Information

  • Established in 1923

Established in 1923

  • Provide Wastewater and Solid Waste

Provide Wastewater and Solid Waste Management for ~ 5.7 million people Management for ~ 5.7 million people

  • 1400 miles of main trunk sewers

1400 miles of main trunk sewers

  • 11 wastewater treatment plants

11 wastewater treatment plants

  • 3 active landfills

3 active landfills

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SLIDE 3

Presentation Outline Presentation Outline Presentation Outline

  • Regulatory Requirements

Regulatory Requirements

  • Nitrification/

Nitrification/Denitrification Denitrification Basics Basics

  • Case Studies:

Case Studies:

  • Valencia WRP

Valencia WRP

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SLIDE 4
  • In 1994, Los Angeles RWCQB set new

In 1994, Los Angeles RWCQB set new nitrogen discharge limits effective in 2003: nitrogen discharge limits effective in 2003:

  • Ammonia: Nominally 2 mg/L

Ammonia: Nominally 2 mg/L

  • Nitrate + Nitrite: 10 mg/L (in some cases

Nitrate + Nitrite: 10 mg/L (in some cases lower) lower)

New Nitrogen Discharge Limits New Nitrogen Discharge Limits New Nitrogen Discharge Limits

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SLIDE 5

Biological Removal of Nitrogen Nitrification/Denitrification (NDN) Process Biological Removal of Nitrogen Biological Removal of Nitrogen Nitrification/ Nitrification/Denitrification Denitrification (NDN) Process (NDN) Process

Nitrification (Aerobic) Nitrification (Aerobic) Denitrification (Anoxic) Denitrification (Anoxic) Reduction Reaction Reduction Reaction

Nitrogen Gas Nitrogen Nitrogen Gas Gas

N2 N N2

2

Anoxic Anoxic Anoxic

Denitrifying Bacteria & Carbon Source Denitrifying Denitrifying Bacteria Bacteria & & Carbon Source Carbon Source

Ammonia Ammonia Ammonia

NH4

+- N

NH NH4

4 + +-

  • N

N

Aerobic Aerobic Aerobic

Nitrite Nitrite Nitrite Nitrate Nitrate Nitrate

Nitrifying Bacteria (Nitrosomonas) Nitrifying Bacteria (Nitrosomonas) Nitrifying Bacteria (Nitrobactor) Nitrifying Bacteria (Nitrobactor)

NO2

  • - N

NO NO2

2

  • -
  • N

N NO3

  • - N

NO NO3

3

  • -
  • N

N

Aerobic Aerobic Aerobic

Oxidation Reaction Oxidation Reaction

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SLIDE 6
  • Step Feed NDN Process
  • Step Feed NDN Process

Step Feed NDN Process

Primary Effluent Primary Primary Effluent Effluent Final Clarifier Final Final Clarifier Clarifier Tertiary Treatment Tertiary Tertiary Treatment Treatment RAS RAS RAS Waste Activated Sludge (WAS) Waste Activated Waste Activated Sludge (WAS) Sludge (WAS) Anoxic Anoxic Anoxic Aerobic Aerobic Aerobic Anoxic Anoxic Anoxic Aerobic Aerobic Aerobic

  • Modified Ludzack Ettinger (MLE) NDN Process
  • Modified

Modified Ludzack Ettinger Ludzack Ettinger (MLE) NDN Process (MLE) NDN Process

Primary Primary Effluent Effluent Tertiary Tertiary Treatment Treatment Return Activated Sludge Return Activated Sludge Waste Activated Waste Activated Sludge (WAS) Sludge (WAS) Internal Recycle Internal Recycle Internal Recycle Anoxic Zone Anoxic Zone Anoxic Zone Aerobic Zone Aerobic Zone Aerobic Zone Final Clarifier Final Final Clarifier Clarifier

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SLIDE 7

Valencia Water Reclamation Plant Valencia Water Reclamation Plant Valencia Water Reclamation Plant

Valencia Valencia J A O J A O

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SLIDE 8

Valencia WRP

Aerial Photo

Valencia WRP Valencia WRP

Aerial Photo Aerial Photo

Golden State Freeway Golden State Freeway Santa Clara River Santa Clara River Six Flags Magic Six Flags Magic Mountain Mountain North North

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SLIDE 9

Valencia Water Reclamation Plant: Background Information Valencia Water Reclamation Plant: Valencia Water Reclamation Plant: Background Information Background Information

  • Built in 1967

Built in 1967

  • Serves ~ 170,000 residents in Santa

Serves ~ 170,000 residents in Santa Clarita Valley Clarita Valley

  • Rated for 21.6 MGD

Rated for 21.6 MGD

  • Current influent flow ~16 MGD

Current influent flow ~16 MGD

  • Discharges to Santa Clara River

Discharges to Santa Clara River

  • Handles all solids from Valencia and

Handles all solids from Valencia and Saugus WRPs Saugus WRPs

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SLIDE 10
  • In 1994:

In 1994: RWQCB set new nitrogen limits effective in RWQCB set new nitrogen limits effective in June 2003: June 2003: Ammonia: 2.0 mg/L Ammonia: 2.0 mg/L Nitrate + Nitrite: 10 mg/L Nitrate + Nitrite: 10 mg/L

Nitrogen Discharge Limits at Valencia WRP Nitrogen Discharge Limits at Nitrogen Discharge Limits at Valencia WRP Valencia WRP

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SLIDE 11

Valencia WRP

Stage Five Expansion and NDN Facilities

Valencia WRP Valencia WRP

Stage Five Expansion and NDN Facilities Stage Five Expansion and NDN Facilities

GO BEARS GO BEARS

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SLIDE 12

Valencia WRP

Aeration Modifications

Valencia WRP Valencia WRP

Aeration Modifications Aeration Modifications

RAS/Filtrate Treatment Tanks RAS/Filtrate Treatment Tanks RAS/Filtrate Treatment Tanks

Unit 3 Unit 3 Unit 4 Unit 4 Unit 5 Unit 5 Unit 1 Unit 1 Unit 2 Unit 2

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SLIDE 13

Valencia WRP

Filtrate

Valencia WRP Valencia WRP

Filtrate Filtrate

Raw and Waste Activated Sludge (Valencia & Saugus WRPs) Raw and Waste Activated Sludge (Valencia & Saugus WRPs) Anaerobic Anaerobic digesters digesters Solids dewatering Solids dewatering filter press filter press

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SLIDE 14
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SLIDE 15

Valencia WRP

Filtrate

Valencia WRP Valencia WRP

Filtrate Filtrate

Solids dewatering Solids dewatering filter press filter press Raw and Waste Activated Sludge (Valencia & Saugus WRPs) Raw and Waste Activated Sludge (Valencia & Saugus WRPs) Biosolids Biosolids for land for land application application Anaerobic Anaerobic digesters digesters

R A S/Filtrate R A S/Filtrate treatment tanks treatment tanks

Filtrate Filtrate (1.5 MG/wk

(1.5 MG/wk ammonia conc. ~900 mg/l) ammonia conc. ~900 mg/l)

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SLIDE 16
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SLIDE 17

Valencia WRP

Filtrate

Valencia WRP Valencia WRP

Filtrate Filtrate

Solids dewatering Solids dewatering filter press filter press

R A S/Filtrate R A S/Filtrate treatment tanks treatment tanks

Raw and Waste Activated Sludge (Valencia & Saugus WRPs) Raw and Waste Activated Sludge (Valencia & Saugus WRPs) Filtrate Filtrate (1.5 MG/wk

(1.5 MG/wk ammonia conc. ~900 mg/l) ammonia conc. ~900 mg/l)

Biosolids Biosolids for land for land application application Anaerobic Anaerobic digesters digesters

Aeration Aeration Units Units

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SLIDE 18

25.6 22.6 23.7 25.5 26.1 24.8 24.1 24.1 10 20 30 40

Ammonia Conc. (mg/L)

SJC-E SJC-W L C L B POM W N SAUG

Water Reclamation Plants Water Reclamation Plants Water Reclamation Plants

25.6 22.6 23.7 25.5 26.1 24.8 24.1 24.1 10 20 30 40

Ammonia Conc. (mg/L)

SJC-E SJC-W L C L B POM W N SAUG

From Filtrate From Filtrate

38.6 38.6 38.6

13.0 13.0

Valencia WRP Ammonia Load Valencia WRP Valencia WRP Ammonia Load Ammonia Load

Water Reclamation Plants Water Reclamation Plants Water Reclamation Plants

VAL

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SLIDE 19

Valencia WRP NDN Start-Up Valencia WRP NDN Start Valencia WRP NDN Start-

  • Up

Up

  • Start-Up began in May, 2003
  • Start

Start-

  • Up began in May, 2003

Up began in May, 2003

* * Effluent

Effluent

Sample Sample Goal Goal

Ammonia (NH Ammonia (NH4

4 + +-

  • N)

N) < 1 mg/L < 1 mg/L < 2 mg/L < 2 mg/L Nitrate (NO Nitrate (NO3

3

  • N)

N)

14 mg/L 14 mg/L

< 10 mg/L < 10 mg/L

  • Modified Ludzack Ettinger (MLE) Mode
  • Modified

Modified Ludzack Ettinger Ludzack Ettinger (MLE) Mode (MLE) Mode

  • Pri. Effluent

Pri

  • Pri. Effluent

. Effluent RAS/Filtrate RAS/Filtrate RAS/Filtrate

Anoxic Zone Anoxic Zone Aerobic Zone Aerobic Zone Aerobic Zone Aerobic Zone To Final Clarifiers To Final Clarifiers

* * *

I R I R

150%Q 150%Q 150%Q

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SLIDE 20

Valencia WRP High Nitrate: Rising Sludge Valencia WRP High Nitrate: Valencia WRP High Nitrate: Rising Sludge Rising Sludge

Mixed Liquor sample Mixed Liquor Mixed Liquor sample sample

D N D N D N N N2

2

Nitrogen Nitrogen Gas Gas NO NO3

3

  • -
  • N

N Nitrate Nitrate Anoxic Anoxic Anoxic

Rising Sludge due to high nitrate Rising Sludge due Rising Sludge due to high nitrate to high nitrate Normal situation in the final clarifier Normal situation in Normal situation in the final clarifier the final clarifier Solids settle to the Solids settle to the bottom of the tank bottom of the tank

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SLIDE 21

Valencia WRP Start-Up Problems: Short Circuiting Valencia WRP Start Valencia WRP Start-

  • Up Problems: Short

Up Problems: Short Circuiting Circuiting

RAS/Filtrate RAS/Filtrate RAS/Filtrate

Anoxic Zone Anoxic Zone Anoxic Zone Aerobic Zone Aerobic Zone Aerobic Zone Aerobic Zone Aerobic Zone Aerobic Zone

I R I R I R

To Final Clarifiers To Final Clarifiers To Final Clarifiers

Primary Effluent Primary Primary Effluent Effluent

  • Internal Recycle Pump

Discharge piping: 30” diameter

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SLIDE 22

Short Circuiting Solution Short Circuiting Solution Short Circuiting Solution

  • Eliminate Internal Recycle flow Short Circuiting
  • Eliminate Internal Recycle flow Short Circuiting
  • When IR rate at 250%Q: Effluent Nitrate: ~10 mg/L

When IR rate at 250%Q: Effluent Nitrate: ~10 mg/L

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SLIDE 23

Valencia WRP Start-Up Problems: Incomplete Denitrification Valencia WRP Start Valencia WRP Start-

  • Up Problems:

Up Problems: Incomplete Incomplete Denitrification Denitrification

  • Not enough COD available for

complete denitrification to occur:

  • Typically need 5 grams COD per gram

NO3

  • N for complete dentrification
  • Not enough retention time in anoxic zones
  • Not enough COD available for

Not enough COD available for complete complete denitrification denitrification to occur: to occur:

  • Typically need 5 grams COD per gram

Typically need 5 grams COD per gram NO NO3

3 -

  • N for complete

N for complete dentrification dentrification

  • Not enough retention time in anoxic zones

Not enough retention time in anoxic zones

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SLIDE 24

Biological Removal of Nitrogen Nitrification/Denitrification (NDN) Process Biological Removal of Nitrogen Biological Removal of Nitrogen Nitrification/ Nitrification/Denitrification Denitrification (NDN) Process (NDN) Process

Nitrification (Aerobic) Nitrification (Aerobic) Denitrification (Anoxic) Denitrification (Anoxic) Reduction Reaction Reduction Reaction

Nitrogen Gas Nitrogen Nitrogen Gas Gas

N2 N N2

2

Anoxic Anoxic Anoxic

Denitrifying Bacteria & Carbon Source Denitrifying Denitrifying Bacteria Bacteria & & Carbon Source Carbon Source

Ammonia Ammonia Ammonia

NH4

+- N

NH NH4

4 + +-

  • N

N

Aerobic Aerobic Aerobic

Nitrite Nitrite Nitrite Nitrate Nitrate Nitrate

Nitrifying Bacteria (Nitrosomonas) Nitrifying Bacteria (Nitrosomonas) Nitrifying Bacteria (Nitrobactor) Nitrifying Bacteria (Nitrobactor)

NO2

  • - N

NO NO2

2

  • -
  • N

N NO3

  • - N

NO NO3

3

  • -
  • N

N

Aerobic Aerobic Aerobic

Oxidation Reaction Oxidation Reaction

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SLIDE 25

Incomplete Denitrification Solutions Incomplete Incomplete Denitrification Denitrification Solutions Solutions

  • Stopped anionic polymer addition at

Primary Tanks

  • Extended anoxic zones from ~33% of tank

volume to ~50% of tank volume

  • Stopped anionic polymer addition at

Stopped anionic polymer addition at Primary Tanks Primary Tanks

  • Extended anoxic zones from ~33% of tank

Extended anoxic zones from ~33% of tank volume to ~50% of tank volume volume to ~50% of tank volume

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SLIDE 26

Pri

  • Pri. Effluent

. Effluent RAS/Filtrate RAS/Filtrate

Anoxic Zone Anoxic Zone (33%) (33%) Aerobic Zone Aerobic Zone Aerobic Zone (67%) Aerobic Zone (67%)

I R I R

To Final Clarifiers To Final Clarifiers

  • Pri. Effluent
  • Pri. Effluent

RAS/Filtrate RAS/Filtrate

Anoxic Zone (50%) Anoxic Zone (50%) Aerobic Zone (50%) Aerobic Zone (50%)

I R I R

To Final Clarifiers To Final Clarifiers

Extended Anoxic Zone Extended Anoxic Zone Extended Anoxic Zone

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SLIDE 27
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SLIDE 28

Unit 3 Unit 3 NO NO3

3

  • N

N Unit 4 Unit 4 NO NO3

3

  • N

N Unit 5 Unit 5 NO NO3

3

  • N

N Before units Before units modified modified 13 mg/L 13 mg/L 13.3 mg/L 13.3 mg/L 12.1 mg/L 12.1 mg/L After all After all units units modified* modified* 7.4 mg/L 7.4 mg/L 6.3 mg/L 6.3 mg/L 7.0 mg/L 7.0 mg/L

* * Six Month Average

Six Month Average

Effluent Nitrate Results: Before and Effluent Nitrate Results: Before and After Modifications After Modifications

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SLIDE 29
  • In 1994:

In 1994: RWQCB set new nitrogen limits effective in 2003: RWQCB set new nitrogen limits effective in 2003: Ammonia: 2.0 mg/L Ammonia: 2.0 mg/L Nitrate + Nitrite: 10 mg/L Nitrate + Nitrite: 10 mg/L

Nitrogen Limits at Valencia WRP Nitrogen Limits at Valencia WRP Nitrogen Limits at Valencia WRP

  • In 2003:

In 2003: RWQCB revised nitrogen limits effective in RWQCB revised nitrogen limits effective in 2009: 2009: Ammonia: 1.75 mg/L Ammonia: 1.75 mg/L Nitrate + Nitrite: 6.8 mg/L Nitrate + Nitrite: 6.8 mg/L

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SLIDE 30

Revised Permit Limits and New Revised Permit Limits and New Performance Concerns Performance Concerns

2 4 6 8 10 12

Jul-03 Oct-03 Jan-04 Apr-04 Jul-04 Oct-04 Jan-05

Effluent NO 3-N (mg N/L) 2003 NO3

  • N limit

2009 NO3

  • N limit
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SLIDE 31

Valencia WRP Valencia WRP Valencia WRP

Primary

Effluent

Primary Primary

Effluent Effluent RAS/

Filtrate

RAS RAS/

/ Filtrate Filtrate

Anoxic Anoxic Zone Zone

Aeration Units 1 and 2: MLE Mode Aeration Units 1 and 2: MLE Mode Aeration Units 1 and 2: MLE Mode

Swing Zone Swing Zone Aerobic Aerobic Zone Zone Aerobic Aerobic Zone Zone To Final Clarifiers To Final Clarifiers

IR IR IR

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SLIDE 32

Valencia WRP Valencia WRP Valencia WRP

Primary

Effluent

Primary Primary

Effluent Effluent RAS/

Filtrate

RAS RAS/

/ Filtrate Filtrate

Anoxic Anoxic Zone Zone

Aeration Units 1 and 2: Step Feed Aeration Units 1 and 2: Step Feed Aeration Units 1 and 2: Step Feed

Aerobic Aerobic Zone Zone Aerobic Aerobic Zone Zone To Final Clarifiers To Final Clarifiers Anoxic Anoxic Zone Zone Anoxic Anoxic Zone Zone

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SLIDE 33

Valencia WRP Valencia WRP Valencia WRP

Primary

Effluent

Primary Primary

Effluent Effluent RAS/

Filtrate

RAS RAS/

/ Filtrate Filtrate

Anoxic Anoxic Zone Zone

Aeration Units 1 and 2: Hybrid Aeration Units 1 and 2: Hybrid Aeration Units 1 and 2: Hybrid

Aerobic Aerobic Zone Zone Aerobic Aerobic Zone Zone To Final Clarifiers To Final Clarifiers

IR IR IR

Anoxic Anoxic Zone Zone Anoxic Anoxic Zone Zone

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SLIDE 34
  • Step Feed NDN Process: Unit 1
  • Step Feed NDN Process: Unit 1

Step Feed NDN Process: Unit 1

Primary Effluent Primary Primary Effluent Effluent Final Clarifier Final Final Clarifier Clarifier Tertiary Treatment Tertiary Tertiary Treatment Treatment RAS RAS RAS Waste Activated Sludge (WAS) Waste Activated Waste Activated Sludge (WAS) Sludge (WAS)

  • Hybrid NDN Process: Unit 2
  • Hybrid NDN Process: Unit 2

Hybrid NDN Process: Unit 2

Primary Effluent Primary Primary Effluent Effluent Final Clarifier Final Final Clarifier Clarifier Tertiary Treatment Tertiary Tertiary Treatment Treatment Waste Activated Sludge (WAS) Waste Activated Waste Activated Sludge (WAS) Sludge (WAS) IR IR IR RAS RAS RAS

  • MLE NDN Process: Unit 3
  • MLE NDN Process: Unit 3

MLE NDN Process: Unit 3

Primary Primary Effluent Effluent Final Final Clarifier Clarifier Tertiary Tertiary Treatment Treatment Waste Activated Waste Activated Sludge (WAS) Sludge (WAS) IR IR IR RAS RAS

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SLIDE 35

Performance Comparison Performance Comparison Mid Mid-

  • day NO

day NO3

3 -

  • N Levels

N Levels

Cumulative Frequency

0.0 0.1 1.0 10.0 30.0 50.0 70.0 90.0 99.0 99.9 100.0

NO3-N Concentration (mg/L)

0.0 4.0 8.0 12.0 16.0

MLE Step Feed Hybrid

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SLIDE 36

Pri

  • Pri. Effluent

. Effluent RAS/Filtrate RAS/Filtrate

Anoxic Zone Anoxic Zone Aerobic Zone Aerobic Zone

I R I R

To Final Clarifiers To Final Clarifiers

Unit 5: Convert from MLE to Hybrid Unit 5: Convert from MLE to Hybrid Unit 5: Convert from MLE to Hybrid

MLE Mode MLE Mode MLE Mode

Pri

  • Pri. Effluent

. Effluent RAS/Filtrate RAS/Filtrate

Anoxic Zone Anoxic Zone Aerobic Zone Aerobic Zone Aerobic Zone Aerobic Zone

I R I R

To Final Clarifiers To Final Clarifiers Anoxic Zone Anoxic Zone

Hybrid Mode Hybrid Mode Hybrid Mode

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SLIDE 37

GO BEARS GO BEARS

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SLIDE 38

Unit 3 Unit 3 MLE MLE Unit 4 Unit 4 MLE MLE Unit 5 Unit 5 Hybrid Hybrid 6/2006 to 12/2006 6/2006 to 12/2006 Peak NO Peak NO3

3 – – N

N 8.2 mg/L 8.2 mg/L 8.3 mg/L 8.3 mg/L 6.4 mg/L 6.4 mg/L

Effluent Nitrate Results: Hybrid vs. Effluent Nitrate Results: Hybrid vs. MLE MLE

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SLIDE 39

Baffle Boxes and Internal Recycle Baffle Boxes and Internal Recycle Diffuser Diffuser

Pri

  • Pri. Effluent

. Effluent RAS/Filtrate RAS/Filtrate

Anoxic Zone Anoxic Zone Aerobic Zone Aerobic Zone Aerobic Zone Aerobic Zone

I R I R

To Final Clarifiers To Final Clarifiers Anoxic Zone Anoxic Zone

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SLIDE 40
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SLIDE 41

Filtrate Equalization Filtrate Equalization Filtrate Equalization

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SLIDE 42

Valencia WRP: Additional NDN Valencia WRP: Additional NDN Optimization Optimization

  • Converted All Units to Hybrid

Converted All Units to Hybrid

  • Baffle Modifications and IR Diffusers

Baffle Modifications and IR Diffusers

  • Filtrate Equalization

Filtrate Equalization

  • Optimized RAS and Internal Recycle Flow

Optimized RAS and Internal Recycle Flow Rates Rates

  • Higher MLSS

Higher MLSS

  • Permanent Submerged Mixers in New

Permanent Submerged Mixers in New Anoxic Zones Anoxic Zones

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SLIDE 43

2 4 6 8 10 Jun-03 Jun-04 Jun-05 Jun-06 Jun-07 Jun-08 Jun-09 Jun-10

Effluent NO3-N and NH4-N (mg N/L)

2009 NO3

  • N limit

2009 NH4

  • N limit

Nitrate Ammonia

Valencia: Effluent Nitrogen Valencia: Effluent Nitrogen Concentrations Concentrations

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SLIDE 44

Acknowledgements Acknowledgements

  • WRP Operations, Maintenance, E&I,

WRP Operations, Maintenance, E&I, and Engineering and Engineering

  • Wastewater Research Section

Wastewater Research Section

  • Laboratories

Laboratories

  • Monitoring Section

Monitoring Section

  • Wastewater Design Section

Wastewater Design Section