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
THE TEAM
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
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
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
Drivers & Challenges
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
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
Activated-sludge
– Chemical
demand
Aeration
55.6%
– Space
– Carbon footprint
– Greenhouse gas emissions.
•
Increased Capital & Operating
Costs & Complexity
Conventional BNR processes require significant
aeration energy typically accounting for half the
electrical demand at a plant.
Distribution of Energy Usage for a Typical BNR WWTP
Lighting & Misc. 2%
UV Disinfection 4%
Chlorination 0%
Centrifuge 8%
Belt Filter Press 1%
Pumping & Screening 7%
Aerated Grit Removal 1%
Primary Clarifiers 1%
Anaerobic Digestion
9%
Gravity Belt
Thickener 1%
Dissolved
Air Flotation 7%
Gravity Thickening
Activated-sludge
0%
Aeration
55.6%
Filtration 2%
Aeration
48%
Filter Feed Pumping 4%
Chemical Addition 2%
Secondary Clarifiers 1%
RAS Pumping 2%
400 MLD (105 mgd) Nitrifying Activated Sludge Facility
Fundamentals of Nitrification - Denitrification
Heterotrophic Denitrification
Autotrophic Nitrification
1 mol Nitrate
(NO3- )
Aerobic Environment
Anoxic Environment
40% Carbon
25% O2
1 mol Nitrite
(NO2- )
1 mol Nitrite
(NO2- )
60% Carbon
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 4.77 g COD / g NO-3-N reduced
The Road to Sustainable and Efficient
Nitrogen Management
1.
2.
3.
– Maximize carbon capture
– Maximize energy recovery
– Minimize carbon & energy demand for N & P removal
A-Stage
Biosolids
B-Stage
3
1
2
3
Fundamentals of Nitritation - Denitritation
Autotrophic Nitritation
Heterotrophic Denitrification
1 mol Nitrate
(NO3- )
Aerobic Environment
25% O2
Anoxic Environment
40% Carbon
•
25% reduction in Oxygen
•
40 % reduction in Carbon demand
•
40% reduction in Biomass production
1 mol Nitrite
(NO2- )
1 mol Nitrite
(NO2- )
60% Carbon
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 2.86 g COD / g NO-3-N reduced
Fundamentals of Deammonification
Partial Nitritation
Aerobic Environment
1 mol Nitrate
(NO3- )
ANAMMOX Deammonification
Anaerobic Ammonium Oxidation Autotrophic
Nitrite Reduction
40% Carbon Strous et. al. 1999)
(New Planctomycete,
• > 60% reduction in Oxygen
NH4+ + 1.32 NO2- + 0.066 HCO3- + 0.13 H+
• Eliminate demand for supplemental carbon
0.26 NO3- + 1.02N2 + 0.066 CH2O0.5N0.15 + 2.03 H2O
25% O2
• 50% of the alkalinity demand
0.57 mol NO2-
Partial Nitritation 40% O2
50% Alkalinity
1 mol Ammonia
(NH3/ NH4 +)
0.44 mol N2+ 0.11 NO3Oxygen demand 1.9 g / g NH+4-N oxidized
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
Typical Energy Demand Ranges
7
6
kW-hr / kg N removed
•
5
4
3
2
1
0
Nitrification /
Denitrification
Nitritation /
Denitritation
Deammonification
(a.k.a. ANAMMOX)
Challenges of the Anammox Organism
• Low Growth Rate
 approx. 10 day doubling time at 30C
 <10 day has been reported (Park et. al - 5.3 - 8.9 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 (<10 -15 mg/l)
• Temperature >30C preferred
• pH (neutral range)
Centrate / Filtrate Characteristics
PST
Activated Sludge
Effluent
RAS
Reduce
Effluent TN
by ≈ 20%
WAS
Thickening
Digestion /
CHP
Sidestream
Deammonification
Centrate
• 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 = 200-800 mg/L
• Temperature 30 - 38C
• Alkalinity insufficient for complete nitrification
• Insufficient carbon for denitrification
Dewatering
Beneficial
Reuse of
Biosolids
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)
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)
•
DEMON®, Cleargreen, Terra-N
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)ANITATM MOx MBBR
ANAMMOX® Upflow
Granular Process
Sidestream Deammonification - Proven Technology
ANAMMOX
DEMON
MBBR
AnitaMox
First
Demonstration
Final Generation
Mature Technology
Second Generation
(building on lessons learned
from first applications)
Terra-N
Pilot IFAS
AnitaMox
Clear Green
First Applications
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
Energy Positive Plants feasible with a combination of
Sidestream and Mainstream Deammonification Coupled
with Efficient Carbon Capture & Energy Recovery
129% energy positive
•
Specific growth rate
(1/d)
1
AOB
Challenges for Mainstream Deammonification
0.8
vs. Sidestream Deammonification
0.6
NOB
0.4
Lower influent & effluent nitrogen concentrations
0.2acid inhibition of NOB
– Lack of free ammonia & low nitrous
0 to outcompete the NOB at lower N
– Reduced competitiveness of the AOB
0
1
2
3
concentrations
Dissolved Oxygen, mg/L
•
Lower and more variable operating 1temperatures
Specific growth rate
(1/d)
AOB
– Slow growth rate of the Anammox
0.8
– Relative growth rates of NOB > AOB at Temperatures < 15-17°C
•
4
0.6
NOB
Higher carbon to nitrogen ratios - OHO
will compete with;
0.4
– AOB for oxygen under aerobic conditions
0.2
– anammox for the nitrite under anoxic conditions.
0
– anammox for organic substrate (certain
0 anammox
1 can denitrify
2 using organic
3
4
acids (Kartal et al. 2007).
Ammonia (AOB) or nitrite (NOB), mg-N/L
Zone 3 complete nitrification
Anthonisen et al. 1976
Chandran & Smets, 2005
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
Increasing diffusivity or mass transfer resistance
• Delft Technical
DC Water, USA
University / Paques /
HRSD, USA
WSHD – Dokhaven,
AIZ Strass/ARA Consult, Austria
Netherlands
Glarnarland/Cyklar-Stulz, Austria
Changi WRP, Singapore PUB
Bejing Technical University, China
Beijing Drainage Group, China
Harbin IT, China
• Veolia Water, France
Attached
Growth
Biofilm
e.g. RBC,
MBBR,
Biofilter
• Ghent University RBC
• Veolia Water, France
WERF Mainstream Deammonification Project
3 different sites and scales
DC Water
WWTP Strass
HRSD
Recipe for Success
Do’s and Don’t’s of Mainstream Deammonification
 1.
 2.
1 mol Nitrate
(NO3- )
AOB Growth & Retention
Anammox Growth &
Retention
Ordinary
0.57 mol NO2- Heterotrophs
(OHO)
40%
Carbon
1 mol Nitrite
(NO2- )
60%
Carbon
3. Control OHO Activity
AnAOB /
Anammox
4.
Limit NOB Growth
1 mol Ammonia
(NH3/ NH4 +)
0.44 mol N2+ 0.11 NO3-
Do’s and Don’t’s of Mainstream Deammonification
 1.
 2.
AOB Growth & Retention
–
–
–
Bioaugmentation
NH3-N concentrations > 2
Dissolved Oxygen > 2
AnAOB /
Anammox
Anammox Growth
& Retention
–
–
Bioaugmentation
Cyclones, Sieves
3. Control OHO Activity
4.
0.57 mol NO2-
Limit NOB Growth
1 mol Ammonia
(NH3/ NH4 +)
0.44 mol N2+ 0.11 NO3-
Bioaugment mainstream with AOB & anammox from
sidestream “incubator”
Bioaugmentation of AOB and
Anammox from Side Stream
Filtrate Deammonification Facility
Post Anoxic
Polishing
Convert “B” stage to
mainstream
deammonification
Anammox Retention in Mainstream
Viable Mechanisms Under Investigation:
1.
2.
3.
4.
5.
Cyclones
Sieves
Membranes
Granules
Biofilms
• MBBR
• RBC
- Strass & Glarnarland
- Blue Plains
- Singapore PUB, American Water
- Delft TU / Paques
- Veolia, HRSD
- Ghent University
Commonly accepted that growth rate and
affinity for oxygen AOB > NOBs
•
Conventional Wisdom based on pure cultures of Nitrobacter
Bench Scale Testing
- Cyclical DO Operational Scenarios
Low/Constant DO
Low DO/Intermittent aeration
High DO/Intermittent aeration
Intermittent Low DO Aeration
“N Profiles”
Still significant NOB activity
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
Bench Scale Testing - Cyclical DO Operational Scenarios
Low/Constant DO
Low DO/Intermittent aeration
High DO/Intermittent aeration
Intermittent High DO Aeration
“N Profiles”
Almost no NOB Activity
Stochiometric NO3-N production (11% as NO3-N)
Specific growth r
(1/d)
0.8
NOB
0.6
For Optimal AOB Growth
0.4
Maintain Higher NH3-N concentrations
Maintain NH3-N >2 mg/l
NOB are able0to compete effectively with AOB for oxygen at low NH3-N
1
2
3
4
concentrations 0
Dissolved Oxygen, mg/L
1
Specific growth rate
(1/d)
•
•
0.2
AOB
0.8
NOB
0.6
0.4
0.2
0
0
1
2
3
Ammonia (AOB) or nitrite (NOB), mg-N/L
Chandran and Smets (2005) Water Research, 39, 4969
4
Intermittent High DO Aeration
Low Ammonia
Without Residual Ammonia
Low Ammonia Residual
NOB begin to Thrive
Do’s and Don’t’s of Mainstream Deammonification
1. AOB Growth & Retention
–
–
–
2. Anammox Growth &
Retention
–
–
1 mol Nitrate
(NO3- )
Bioaugmentation
NH3-N concentrations > 2
Dissolved Oxygen > 2
0.57 mol NO2-
Ordinary
Heterotrophs
(OHO)
40%
Carbon
1 mol Nitrite
(NO2- )
60%
Carbon
Bioaugmentation
Cyclones, Sieves
AnAOB /
Anammox
3. Control OHO Activity
4. Limit NOB Growth
1 mol Ammonia
(NH3/ NH4 +)
0.44 mol N2+ 0.11 NO3-
The Road to Sustainable and Efficient
Nitrogen Management
1.
2.
3.
A-Stage
Biosolids
B-Stage
1
– Maximize carbon capture
– Maximize energy recovery
– Minimize carbon & energy demand for N & P removal
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
Medium C:N
6 - 10 :1 range?
3 - 5 :1 range?
Anammox
Outcompete OHO
OHO Outcompete Anammox
Conventional Nitrification /
Denitrification
Lower C:N ratio
1 - 3 :1 range ?
Nitrite Shunt
Deammonification
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
Expansion
2. Convert “B” stage to
mainstream
deammonification
3. CEPT
Carbon to
Digesters/ CHP
4. Mechanisms for NOB Repression
a) 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
b) Inhibition of NOB
–
–
–
–
Hydroxylamine ?
Hydrazine ?
Nitric Oxide ?
Formic acid ?
NOB Repression / Inhibition Opportunities
Inhibitors/conditions
Literature
Mainstream Conditions
(mg N/L)
(mg N/L)
(mg N/L)
Free ammonia (NH4+)
0.04 - 0.08
0.005 - 0.1
0.2 - 0.4 (centrate contact)
Free nitrous acid (HNO2)
0.01-0.8
<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)
0.007-0.448
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
Transient anoxia
High DO
Very Effective
4. Mechanisms for NOB Repression
c) 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
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
1. Baffles in stages 2&4
2. Use aeration grids in aerobic
zones and mixers in anoxic
zones
3. Motor actuated butterfly
valves and air flow meters for
process air
4. Add feed channels & gates to
anoxic zones 2b, 3b
5. CEPT by-pass
6. NH3-N and NOx-N probes for
process control (e.g. AVN
controller by HRSD)
Mainstream Deammonification Implementation Strategy
for Blue Plains
3. HRAS “A” stage
Adsorption of colloidal & sCOD.
Carbon to Digesters/ CHP
Post
Anoxic or
Anammox
Polishing
1. & 2. Bioaugmentation of AOB
and Anammox from Side Stream
Filtrate Deammonification Facility
Step-feed tanks with sequential aerobic
anoxic zones & swing zones for post
aerobic polishing
Cyclones for anammox retention
3. CEPT
Particulate Carbon to
Digesters/ CHP
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
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
Mainstream Deammonification Implementation Strategy
for Blue Plains
3. HRAS “A” stage
Adsorption of colloidal & sCOD.
Carbon to Digesters/ CHP
1. & 2. Bioaugmentation of AOB
and Anammox from Side Stream
Filtrate Deammonification Facility
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
3. CEPT
Particulate Carbon to
Digesters/ CHP
Single point
carbon addition
Proof of the Pudding
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:
800 000 m3/day.
Tropical climate: sewage
temperature between 28-32 °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
Changi’s Positive Performance Provided Proof of Concept
144 m
Basin 6 (Of f line)
Zone 4
Anoxic
• 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
Basin 1
Zone 4
Anoxic
Aerobic
Zone
Basin 2
Zone 4
Anoxic
Aerobic
Zone
Basin 3
Zone 4
Anoxic
Aerobic
Zone
Basin 4
Zone 4
Anoxic
Aerobic
Zone
Basin 5
Zone 4
Anoxic
Aerobic
Zone
Aerobic
Zone
Zone 3
Anoxic
Zone 3
Anoxic
Zone 3
Anoxic
Zone 3
Anoxic
Zone 3
Anoxic
Zone 3
Anoxic
Zone 2
Anoxic
Zone 2
Anoxic
Zone 2
Anoxic
Zone 2
Anoxic
Zone 2
Anoxic
Zone 2
Anoxic
Zone 1
Anoxic
Zone 1
Anoxic
Zone 1
Anoxic
Zone 1
Anoxic
Zone 1
Anoxic
Zone 1
Anoxic
50 m
RAS
To SST
PE
Basin 6 under maintenance
Inlet of anoxic zone
Sampling Point
Ammonia
Nitrite
Nitrate
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 0 - 1.7 mg/L).
Heavily loaded during winter ski season
– Temp 10-12°C range
– Nitrite shunt / deammonification observed
nitrogen
N/L)
(mgN/L)
concentration(mg
nitrogenconcentration
Full Scale Success with
Mainstream Nitrite Shunt / Deammonification
25
2010/2011NO3-N
NO3-N effluent
effluent
2010/2011
2010/2011 NO2-N
NO2-N effluent
2010/2011
effluent
20
2011/2012 NO3-N
2011/2012
NO3-Neffluent
effluent
2011/2012 NO2-N
2011/2012
NO2-Neffluent
effluent
Conventional MLE BNR 2010
15
Mainstream nitrite Shunt /
Deammonification 2011
10
5
0
1-Dec
1-Dec
11-Dec
31-Dec
21-Dec
30-Jan
31-Dec
29-Feb
10-Jan
30-Mar
20-Jan
29-Apr
30-Jan
29-May
Conclusions
• Nitrite Shunt / Mainstream Deammonification strategy promising
• Demonstrated successfully at full scale
– Strass, Austria
– Changi, Singapore PUB
(cold with bioaugmentation)
(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
Bev Stinson
Beverley.Stinson@aecom.com