1. Roadmap Toward Sustainable Nutrient Management -
The Role of Mainstream Deammonification
Presented by:
Beverley Stinson, Ph.D Global Wastewater Practice Leader, AECOM
Acknowledgements:
Sudhir Murthy, Ahmed Al-Omari & Haydee De Clippeleir DC Water
Charles Bott HRSD
Bernhard Wett, Ph.D ARA Consult
Gregory Bowden AECOM

2. THE TEAM Hansa Keswani Yi Wei Ma Matthew Michaelis Mark Miller
Geert Nyhuis
Sylvia Okogi
Maureen O’Shaughnessy
Hong Keun Park
Sabine Podmirseg
Pusker Regmi
Rumana Riffat
Andrew Shaw
Beverley Stinson
Imre Takacs
Claire Welling
Bernhard Wett
Ahmed Al-Omari
Olawale Akintayo
Charles Bott
Ryder Bunce
Kartik Chandran
Michael Desta
Norman Dockett
Haydee De Clippeleir
Dana Fredericks
Gomez Brandon
Mofei Han
Martin Hell
Becky Holgate
Rebecca Jimenez
Jose Jimenez
David Kinnear

3. Drivers & Challenges for Mainstream Deammonification
Agenda: 01
Drivers & Challenges for Mainstream Deammonification 02
“Recipe” for Success
Mechanisms & Control Strategies
Potential Engineering Implementation Concepts 03
“Proof of the Pudding” – Full Scale Mainstream Deammonification Demonstrations

4. Drivers & Challenges

5. Eutrophication due to excessive nutrient discharge is a global problem
Fundamentally impacting issues such as:
Water security
Public health
Economic and community growth
Tourism
Environmental aesthetics and quality of life

6. While the environmental, social and economic benefits of nutrient management are extensive, they come at a price….
Conventional Biological Nutrient Removal (BNR) processes rely on anaerobic, anoxic and aerobic microbes to remove N&P from wastewater
Nutrient Management at Wastewater Treatment Plants results in increased:
Energy demand
Chemical demand
Space
Carbon footprint
Greenhouse gas emissions.
Increased Capital & Operating Costs & Complexity
Activated-sludge
Aeration 55.6%
Conventional BNR processes require significant aeration energy typically accounting for half the electrical demand at a plant.

7. Distribution of Energy Usage for a Typical BNR WWTP
Activated-sludge
Aeration 55.6%
Focus on the “Big Opportunities” on road to “Energy Neutrality”
Enhanced Digestion / CHP for energy recovery
Activated Sludge Aeration Accounts for Over 50% of Energy Demand
Pumping – Primary Effluent & RAS
400 MLD (105 mgd) Nitrifying Activated Sludge Facility

8. Fundamentals of Nitrification - Denitrification
Heterotrophic Denitrification
Anoxic Environment
Autotrophic Nitrification
Aerobic Environment
1 mol Nitrate
(NO3- )
40% Carbon
Nitrite Oxidizers
(e.g. Nitrobacter)
25% O2
1 mol Nitrite
(NO2- )
1 mol Nitrite
(NO2- )
60% Carbon
Ammonia Oxidizers
(e.g. Nitrosomonas)
75% O2
100% Alkalinity
1 mol Ammonia
(NH3/ NH4 +)
½ mol Nitrogen Gas
(N2 )
Oxygen demand 4.57 g / g NH+4-N oxidized
Carbon demand g COD / g NO-3-N reduced
NH O CH3OH C5H7O2N N H2O CO2 *

9. The Road to Sustainable and Efficient Nitrogen Management
A-Stage – Maximize carbon capture
Biosolids – Maximize energy recovery
B-Stage – Minimize carbon & energy demand for N & P removal 1 3 2

10. Fundamentals of Nitritation - Denitritation
Autotrophic Nitritation
Aerobic Environment
Heterotrophic Denitrification
Anoxic Environment
1 mol Nitrate
(NO3- )
40% Carbon
25% reduction in Oxygen
40 % reduction in Carbon demand
40% reduction in Biomass production
Nitrite Oxidizers
(e.g. Nitrobacter)
25% O2
1 mol Nitrite
(NO2- )
1 mol Nitrite
(NO2- )
60% Carbon
Ammonia Oxidizers
(e.g. Nitrosomonas)
75% O2
100% Alkalinity
1 mol Ammonia
(NH3/ NH4 +)
½ mol Nitrogen Gas
(N2 )
Oxygen demand 3.42 g / g NH+4-N oxidized
Carbon demand g COD / g NO-3-N reduced
NH O CH3OH C5H7O2N N H2O CO2 *

11. Fundamentals of Deammonification
ANAMMOX Deammonification
Anaerobic Ammonium Oxidation Autotrophic Nitrite Reduction
(New Planctomycete, Strous et. al. 1999)
Partial Nitritation
Aerobic Environment
1 mol Nitrate
(NO3- )
40% Carbon
> 60% reduction in Oxygen
Eliminate demand for supplemental carbon
50% of the alkalinity demand
NH NO HCO H+
0.26 NO N CH2O0.5N H2O
Nitrite Oxidizers
(e.g. Nitrobacter)
25% O2
0.57 mol NO2-
Partial Nitritation 40% O2
50% Alkalinity
Ammonia Oxidizers
(e.g. Nitrosomonas)
1 mol Ammonia
(NH3/ NH4 +)
0.44 mol N NO3-
Oxygen demand 1.9 g / g NH+4-N oxidized
NH O CO C5H7O2N N HNO H2O *

12. Overall Benefit of Deammonification Processes
Eliminates need for carbon for TN removal making it available for energy recovery
Significant reduction in energy demand possible
Reduction in alkalinity demand
Wett, B, 2007, “Development and implementation of a robust deammonification process.” Water Science & Technology, 56 (7),

13. Challenges of the Anammox Organism
Low Growth Rate
approx. 10 day doubling time at 30C
<10 day has been reported (Park et. al days)
SRT (>30 days)
Sensitive to;
Nitrite
Toxic- irreversible loss of activity based on concentration & exposure time
NH4+ : NO2- ratio 1 : 1.32
DO - reversible inhibition
Free ammonia (< mg/l)
Temperature >30C preferred
pH (neutral range)
Free ammonia NH3 (unionized ammonia) is highly toxic to fish
Ammonium (ionized ammonia) is virtually non-toxic to fish
Balance define by ph and temperature
High ph high temp = high NH3

14. Centrate / Filtrate Characteristics
Reduce Effluent TN by ≈ 20%
PST
Activated Sludge
Effluent
RAS
WAS
Thickening
Digestion /
CHP
Sidestream
Deammonification
Centrate
Dewatering
1% Plant Influent Flow
Rich in Nitrogen & Phosphorus
15 to 25% Plant Influent TN load
Ammonium Conc. 800 to 2,500 mg-N/L
Centrate TP = mg/L
Temperature C
Alkalinity insufficient for complete nitrification
Insufficient carbon for denitrification
Beneficial
Reuse of Biosolids

15. Sidestream Nitritation – NOB Repression
Control
Elevated NH3-N concentrations
Elevated temperature (30-35 deg C)
Low SRT (1-2 days)
Low DO (~0.5 mg/L)
NOB Repression Mechanisms
Free NH4 –N inhibition of NOB > AOB
Nitrous acid inhibition of NOB > AOB
AOB max growth rate > NOB max growth rate at high temp
AOB DO affinity > NOB DO affinity (perhaps only at high temp)

16. Sidestream Deammonifcation Operational Experience
DEMON® Suspended Growth SBR
15 Operational /11 in Construction
York River, VA, Alexandria, VA, Blue Plains, DC
Cleargreen® Suspended Growth SBR
3 Pilots / 3 WWTPs in Design
Terra-N Hybrid Suspended and Attached
4 Operational Facilities (Germany)
Anita®MOX Attached Growth MBBR
4 Operational / 2 Start-up
James River, VA & South Durham, NC
ANAMMOX® Upflow Granular
11 Operational facilities (4 WWTPs / 7 industrial)
9 in Design / Construction (2 WWTPs / 7 Industrial)
DEMON®, Cleargreen, Terra-N
ANITATM MOx MBBR
ANAMMOX® Upflow Granular Process

17. Sidestream Deammonification - Proven Technology
ANAMMOX
DEMON
Final Generation Mature Technology
MBBR
AnitaMox
Second Generation
(building on lessons learned
from first applications)
First
Demonstration
Free ammonia NH3 (unionized ammonia) is highly toxic to fish
Ammonium (ionized ammonia) is virtually non-toxic to fish
Balance define by ph and temperature
High ph high temp = high NH3
Terra-N
Pilot
IFAS
AnitaMox
First Applications
Clear Green

18. Operational Cost Savings
$8.5M / yr (methanol, alkalinity, sludge processing
9 year payback
Risk Mitigation for effluent TN
Sidestream
Treatment
20,200
lbs /day
NH3-N
Mainstream
Treatment
105,000
lbs/day
TKN

19. Energy Positive Plants feasible with a combination of Sidestream and Mainstream Deammonification Coupled with Efficient Carbon Capture & Energy Recovery
129% energy positive

20. Challenges for Mainstream Deammonification vs
Challenges for Mainstream Deammonification vs. Sidestream Deammonification
Lower influent & effluent nitrogen concentrations
Lack of free ammonia & low nitrous acid inhibition of NOB
Reduced competitiveness of the AOB to outcompete the NOB at lower N concentrations
Lower and more variable operating temperatures
Slow growth rate of the Anammox
Relative growth rates of NOB > AOB at Temperatures < 15-17°C
Higher carbon to nitrogen ratios - OHO will compete with;
AOB for oxygen under aerobic conditions
anammox for the nitrite under anoxic conditions.
anammox for organic substrate (certain anammox can denitrify using organic acids (Kartal et al. 2007).
Anthonisen et al. 1976
Chandran & Smets, 2005
Not so easy to achieve mainstream deammonification for the following reasons;
Lower influent & effluent nitrogen concentrations
Lack of free ammonia & low nitrous acid inhibition of NOB
Reduced competitiveness of the AOB to outcompete the NOB at lower N concentrations
Lower and more variable operating temperatures
Slow growth rate of the Anammox
Relative growth rates of NOB > AOB at Temperatures < 15-17°C
Higher carbon to nitrogen ratios
OHO will compete with;
AOB for oxygen under aerobic conditions
anammox for the nitrite under anoxic conditions.
anammox for organic substrate (certain anammox can denitrify using organic acids (Kartal et al. 2007).
Zone 3 complete nitrification

21. Approaches to Mainstream Nitrite Shunt / Deammonification
Small Flocculant &Suspended Growth Anammox Granules
e.g. Activated Sludge Systems
Large Anammox Granules
e.g. granular sludge systems
Hybrid Suspended & Attached Growth
e.g. IFAS
Attached Growth Biofilm
e.g. RBC, MBBR, Biofilter
Increasing diffusivity or mass transfer resistance
DC Water, USA
HRSD, USA
AIZ Strass/ARA Consult, Austria
Glarnarland/Cyklar-Stulz, Austria
Changi WRP, Singapore PUB
Bejing Technical University, China
Beijing Drainage Group, China
Harbin IT, China
Delft Technical University / Paques / WSHD – Dokhaven, Netherlands
Veolia Water, France
Ghent University RBC
Veolia Water, France

22. Two-Stage Approach to Mainstream Deammonification
Nitrite shunt
Anammox Polishing
Small Flocculant &Suspended Growth AOB
e.g. activated sludge
Attached Growth
anammox
e.g. MBBR
Suspended Growth Nitrite Shunt
Post MBBR Anammox Polishing
HRSD Pilot Concept - Operating Very Successfully

23. WERF Mainstream Deammonification Project 3 different sites and scales
DC Water
WWTP Strass
HRSD

24. Recipe for Success

25. Do’s and Don’t’s of Mainstream Deammonification
1 mol Nitrate
(NO3- ) ü
40%
Carbon
AOB Growth & Retention
Anammox Growth & Retention
Control OHO Activity
Limit NOB Growth
Nitrite Oxidizers
(NOB) ü
Ordinary
Heterotrophs
(OHO)
1 mol Nitrite
(NO2- )
0.57 mol NO2-
60%
Carbon
Ammonia Oxidizers
(AerAOB)
AnAOB /
Anammox
0.44 mol N NO3-
1 mol Ammonia
(NH3/ NH4 +)

26. Do’s and Don’t’s of Mainstream Deammonificationü
AOB Growth & Retention
Bioaugmentation
NH3-N concentrations > 2
Dissolved Oxygen > 2
Anammox Growth & Retention
Cyclones, Sieves
Control OHO Activity
Limit NOB Growth
0.57 mol NO2-
Ammonia Oxidizers
(AerAOB) ü
AnAOB /
Anammox
0.44 mol N NO3-
1 mol Ammonia
(NH3/ NH4 +)

27. Bioaugment mainstream with AOB & anammox from sidestream “incubator”
Bioaugmentation of AOB and Anammox from Side Stream Filtrate Deammonification Facility
Convert “B” stage to mainstream deammonification
Post Anoxic Polishing

28. Anammox Retention in Mainstream
Viable Mechanisms Under Investigation:
Cyclones Strass & Glarnarland
Sieves Blue Plains
Membranes - Singapore PUB, American Water
Granules Delft TU / Paques
Biofilms
MBBR Veolia, HRSD
RBC Ghent University

29. Commonly accepted that growth rate and affinity for oxygen AOB > NOBs
Conventional Wisdom based on pure cultures of Nitrobacter

30. Bench Scale Testing - Cyclical DO Operational Scenarios
Low/Constant DO
Low DO/Intermittent aeration
High DO/Intermittent aeration

31. Intermittent Low DO Aeration “N Profiles”
Still significant NOB activity
~ -6.6 mgN/L
~ +2.4 mgN/L

32. Mixed culture of NOB with Nitrospira more dominant than Nitrobacter
In our experience, at low DO, Growth Rate & Affinity for Oxygen of NOB > AOB
Mixed culture of NOB with Nitrospira more dominant than Nitrobacter
Possibly Nitrospira & other NOB species
AOB-growth
NOB-growth
Monod
µmax * Xa / Ya
193
137
Ko [mg DO/L]
0.04
0.6

33. Bench Scale Testing - Cyclical DO Operational Scenarios
Low/Constant DO
Low DO/Intermittent aeration
High DO/Intermittent aeration

34. Intermittent High DO Aeration “N Profiles”
Almost no NOB Activity
Stochiometric NO3-N production (11% as NO3-N)
~ -8 mgN/L
~ +0.7 mgN/L

35. For Optimal AOB Growth Maintain Higher NH3-N concentrations
Maintain NH3-N >2 mg/l
NOB are able to compete effectively with AOB for oxygen at low NH3-N concentrations
Chandran and Smets (2005) Water Research, 39, 4969

36. Intermittent High DO Aeration Low Ammonia
Without Residual Ammonia NOB begin to Thrive
Low Ammonia Residual
~ +4 mgN/L
~ -8 mgN/L

37. Do’s and Don’t’s of Mainstream Deammonification
AOB Growth & Retention
Bioaugmentation
NH3-N concentrations > 2
Dissolved Oxygen > 2
Anammox Growth & Retention
Cyclones, Sieves
Control OHO Activity
Limit NOB Growth
1 mol Nitrate
(NO3- )
40%
Carbon
Nitrite Oxidizers
(NOB)
Ordinary
Heterotrophs
(OHO)
1 mol Nitrite
(NO2- )
60%
Carbon
0.57 mol NO2-
Ammonia Oxidizers
(AerAOB)
AnAOB /
Anammox
1 mol Ammonia
(NH3/ NH4 +)
0.44 mol N NO3-

38. The Road to Sustainable and Efficient Nitrogen Management
A-Stage – Maximize carbon capture
Biosolids – Maximize energy recovery
B-Stage – Minimize carbon & energy demand for N & P removal 1

39. 3. Control OHO Activity – CEPT & HRAS Adsorption
C:N ratio may be a key control factor in defining predominant pathway for TN removal
Higher C:N ratio
:1 range?
OHO Outcompete Anammox
Medium C:N
3 - 5 :1 range?
Lower C:N ratio
1 - 3 :1 range ?
Anammox Outcompete OHO
Conventional Nitrification / Denitrification
Nitrite Shunt
Deammonification

40. 3. Control OHO Activity – CEPT & HRAS Adsorption
1 & 2. New Side Stream Filtrate Deammonification Facility
“AOB & Anammox growth”
3. HRAS “A” stage
Adsorption of colloidal sCOD
Carbon to Digesters/ CHP
2. Convert “B” stage to mainstream deammonification
Expansion
3. CEPT
Carbon to Digesters/ CHP

41. 4. Mechanisms for NOB Repression
Competition - Outselection
Aerobic conditions - AOB & OHO compete with NOB for O2
Maintain maximum AOB rates by:
Bioaugmentation
Optimal conditions (NH3-N >2 and DO >1.5)
Anoxic conditions – anammox & OHO compete with NOB for nitrite
Bioaugmentation and retention of anammox
Inhibition of NOB
Hydroxylamine ?
Hydrazine ?
Nitric Oxide ?
Formic acid ?
In my view: These inhibition stories at these substrate concentrations are totally irrelevant

42. NOB Repression / Inhibition Opportunities
Inhibitors/conditions
(mg N/L)
Literature
Mainstream Conditions
Free ammonia (NH4+)
(centrate contact)
Free nitrous acid (HNO2)
<0.001
(Max of 5 mg NO2-N/L present)
Hydroxylamine (NH2OH)
0.2
Intermediate of AOBs.
Under evaluation may hold promise
Hydrazine (N2H4)
1.0 (Only for Nitrobacter)
0.1 Produced by Brocadia Anammoxidans
Nitric Oxide (NO)
Depends on nitrite accumulation.
Reversible NOB inhibition but also stimulates anammox growth
Formic Acid (HCOOH)
>100mg/l complete inhibition –
no adverse effect on AerAOBs
Used for fine bubble diffuser cleaning so infrastructure may already exist.
Salinity
> 5
Aeration duration control
DO > 2 mg/l
Using real time pH, DO and ORP control and / or Blower Frequency
Transient anoxia
Low DO
Not effective
High DO
Very Effective

43. 4. Mechanisms for NOB Repression
Transient Anoxia
Lag in nitrite availability for NOB once aeration begins
Intermittent aeration
Deplete DO quickly – avoid sustained low DO high nitrite conditions
Step-feed COD to anoxic zones
CEPT by-pass for extra solCOD as needed
Oxygen
Nitrite
lag
In my view: These inhibition stories at these substrate cooncentartions are totally irrelevant

44. Reactor modifications
Sequential aerobic anoxic zones for transient anoxia “in space”
Transient anoxia “in time” with air cycling on & off also effective
Step-feed to deliver COD to anoxic zones for DO depletion
Baffles in stages 2&4
Use aeration grids in aerobic zones and mixers in anoxic zones
Motor actuated butterfly valves and air flow meters for process air
Add feed channels & gates to anoxic zones 2b, 3b
CEPT by-pass
NH3-N and NOx-N probes for process control (e.g. AVN controller by HRSD)

45. Mainstream Deammonification Implementation Strategy for Blue Plains
1. & 2. Bioaugmentation of AOB and Anammox from Side Stream Filtrate Deammonification Facility
3. HRAS “A” stage
Adsorption of colloidal & sCOD. Carbon to Digesters/ CHP
Step-feed tanks with sequential aerobic anoxic zones & swing zones for post aerobic polishing Cyclones for anammox retention
Post Anoxic or Anammox Polishing
CEPT By-Pass
3. CEPT
Particulate Carbon to Digesters/ CHP

46. Recipe for Mainstream Deammonification
AOB & Anammox Bioaugmentation from sidestream
Anammox Retention in Mainstream
Intermittent high DO “transient anoxia”
At high DO AOB grow faster than NOB
NOB seem to have a delayed response as they move from anoxic to aerobic zones
Maintain residual ammonia > 2 mg/l
Ensure max ammonia oxidation rates so AOB outcompete NOB for DO
Ammonia based aeration control (AVN controller by HRSD)
Rapid transition to anoxia
DO must be scavenged quickly to avoid a “low” DO environment
Step-feed to anoxic zones to deplete DO quickly
CEPT by-pass to enhance soluble COD as needed
Aggressive SRT Control
Lower SRT results in selective washout of NOB at warmer temperatures

47. Recipe for Mainstream Deammonification
Final Polishing Step to reduce:
Residual ammonia
Residual nitrate to nitrite
Can use one of two techniques
Polishing aerobic & anoxic zone to fully nitrify remaining NH4-N and denitrify with supplemental carbon
Use Brocadia Anammoxidans or Methyloversatilis

48. Mainstream Deammonification Implementation Strategy for Blue Plains
1. & 2. Bioaugmentation of AOB and Anammox from Side Stream Filtrate Deammonification Facility
3. HRAS “A” stage
Adsorption of colloidal & sCOD. Carbon to Digesters/ CHP
Step-feed tanks with sequential aerobic anoxic zones & swing zones for post aerobic polishing Cyclones for anammox retention
4. Post Anoxic or Post Anammox Polishing
Single point
carbon addition
CEPT By-Pass
3. CEPT
Particulate Carbon to Digesters/ CHP

49. Proof of the Pudding

50. Changi Water Reclamation Plant (WRP) Warm Climate Full Scale Mainstream Deammonification Demonstration
Full scale demonstration was based upon successful strategies proven at pilot scale
Changi - largest WRP in Singapore: m3/day.
Tropical climate: sewage temperature between °C
Five basins with cyclical anoxic/ aerobic zones.
Feeding: 20% of primary effluent to each anoxic zone
Total SRT: 5 days with 2.5 day SRT for aerobic and anoxic
HRT: 5.7 hours

51. Changi’s Positive Performance Provided Proof of Concept
Observe significant portion of the ammonia converted to nitrite as opposed to nitrate indicating robust NOB suppression
Observe concomitant reduction in ammonia & nitrite in anoxic zones indicating reliable anammox activity
Full scale demonstration of mainstream deammonification
Ammonia
Nitrite
Nitrate

52. Strass WWTP, Austria, Full Scale Demonstration
A-B type plant – ½ day SRT A-Stage followed by B-Stage - >65% COD removed in HRAS
Sidestream DEMON - AOB & anammox Bio-Aug
Cyclones - mainstream anammox retention
Ammonia based aeration control - NH3-N >2 mg/l
Carousel type aeration tank providing high DO transient anoxia (DO mg/L).
Heavily loaded during winter ski season
Temp 10-12°C range
Nitrite shunt / deammonification observed

53. Full Scale Success with Mainstream Nitrite Shunt / Deammonification
Conventional MLE BNR 2010
Mainstream nitrite Shunt /
Deammonification 2011

54. Conclusions
Nitrite Shunt / Mainstream Deammonification strategy promising
Demonstrated successfully at full scale
Strass, Austria (cold with bioaugmentation)
Changi, Singapore PUB (warm without bioaugmentation)
Based upon an evaluation of eight other plants, it seems reasonably feasible to retrofit into an existing activated sludge system
When upgrading, consider incorporating flexibility for future implementation

55. Bev Stinson