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Upgrading WRFs for Biological Nutrient Removal
OWEA Annual Technical Conference and Exhibition
June 25, 2015
• Permitting and Planning
• BNR Overview
• Case Example
• Innovative Approaches
Agenda
Proactive Participation in NPDES Nutrient Permits Can Save Millions
Brown and Caldwell 3
HRSD, Meeting Minutes for
3/23/2010,
“Traditional” Limits • Weekly/Monthly
• Annual, 6-month, or Seasonal
More Recent
• Max day limits - “Stringent” Ammonia and Ultimate Oxygen Demand
• 5-Year
• Bubble Permits • HRSD TN and TP
• Compliance flexibility – Focus on most cost effective upgrades instead of upgrading each WRF
Implementation Periods • 2-4 permit cycles for low nutrients (typ)
NEORSD P Removal - Impact of Averaging Period
Averaging Period
Filtration Capacity Required, mgd
0.5 mg/L TP 0.3 mg/L TP
Easterly (100 mgd annual, 400 mgd peak)
30 Day Average 55 200
90 Day Average 47 150
180 Day Average 43 140
Typical Nutrient Removal Planning Scenarios
Item Ammonia
mgN/L
Total
Nitrogen,
mgN/L
Total
Phosphorus,
mgP/L
Nitrification Varies -- --
Biological Nutrient Removal -- <8 to 10 <1.0
Enhanced Nutrient Removal -- <3 to 4 <0.3
ENR and beyond -- <2 to 3 <0.05 to 0.1
• Different Solutions when overlaying permit averaging
Key Source Material: Research by the Water Environment Research Foundation
• Nutrient impacts are seldom responsive to short term variations
• Study of long term statistics on the performance on exemplary nutrient removal plants
• Examples of nutrient permit bases
• Conclusions about type of technology on performance statistics
Bott and Parker, 2011
Key Source Material: Research by WERF Nutrient Management Vol. 2-Bott & Parker 2011
Study of long term statistics on performance of exemplary nutrient removal systems
% of Values Less Than or Equal to Indicated Value
0.01 0.1 1 10 30 50 70 90 99 99.9 99.99
TP o
r OP
(mg
P/L
)
0.001
0.01
0.1
1
TP
OP
Ln-Normal Values
% of Values Less Than or Equal to Indicated Value
0.01 0.1 1 10 30 50 70 90 99 99.9 99.99
TP o
r OP
(mg
P/L
)
0.001
0.01
0.1
1
TP
OP
Ln-Normal Values
% of Values Less Than or Equal to Indicated Value
0.01 0.1 1 10 30 50 70 90 99 99.9 99.99
TP o
r OP
(mg
P/L
)
0.001
0.01
0.1
1
TP
OP
Ln-Normal Values
% of Values Less Than or Equal to Indicated Value
0.01 0.1 1 10 30 50 70 90 99 99.9 99.99
TP o
r OP
(mg
P/L
)
0.001
0.01
0.1
1
TP
OP
Ln-Normal Values
Daily Weekly
Monthly Annual
N Removal Plants
• 4- or 5-stage Bardenpho plants almost meet TN=3
mg/L, 95% of time; 10 Florida plants achieve 3.5
mg/L. Cold climate Kalkaska plant may reach 3.0
mg/L TN
• Only 4 plants identified meeting max day effluent
NH4-N criterion of 4 mg/L – additional facilities
likely required for reliability
BNR Upgrade Overview
Nitrifying Activated Sludge Plant
Increase SRT to 7.5 -10 days
Additional Bioreactor : 2x to 3x
AEROBIC CLARIFIER
RETURN SLUDGE WASTE SLUDGE
EFFLUENT
Adding Bio-P to Nitrification
Selector:
15-20% Total Volume
Struvite Control
AEROBIC CLARIFIER
RETURN SLUDGEWASTE SLUDGE
EFFLUENT
ANAEROBIC AEROBIC CLARIFIER
RETURN SLUDGEWASTE SLUDGE
EFFLUENT
ANAEROBIC
Capacity Loss ≈ 0
TP < 0.6-1.0 mg /L
(Monthly)
Total Nitrogen Removal
ANOXIC AEROBIC CLARIFIER
RETURN SLUDGE
MIXED LIQUOR RECYCLE
WASTE SLUDGE
EFFLUENT
ANAEROBIC
Anoxic Zone:
≈ 30% Total Volume
TN < 10 mg /L
(Monthly)
Capacity Loss ≈ 20%
Combining TP and TN removal
Struvite Control
TP < 0.7-1 mg/L
TN < 10 mg /L
(Monthly)
ANOXIC AEROBIC CLARIFIER
RETURN SLUDGE
MIXED LIQUOR RECYCLE
WASTE SLUDGE
EFFLUENT
ANAEROBIC
Anoxic Zone:
≈ 30% Total Volume Selector:
15-20% Total Volume
Capacity Loss ≈ 25-30%
Further Reducing Phosphorus Discharges
Alum
Dual Media or
Deep Bed Filters
Membranes
Scenario Effluent TP, mg P/L
Monthly Annual
Filters <0.3 <0.2-0.3
Membranes <0.2 <0.1-0.2
Alum
Dual Media or
Deep Bed Filters
Membranes
Scenario Effluent TP, mg P/L
Monthly Annual
Filters <0.1 <0.1
Membranes <0.1 <0.1
CoMag w/o Filters <0.1 <0.1
Process Type
Performance of Exemplary Plants,
Max Month Performance,EPA and
WERF Study, TN mg/L
Influent Carbon for Denitrification 4 to 11
Influent Carbon and External Carbon (with
Filtration) <4
Nitrify First, Denitrify with External Carbon
(with Filtration) <3
Combination (with Filtration) 3 to 4
Total Nitrogen Removal: Building on what you own
Influent Carbon and External Carbon (with Filtration) 5-Stage Bardenpho Process
AEROBIC ANOXIC AEROBIC CLARIFIER
RETURN SLUDGE
MIXED LIQUOR RECYCLE
WASTE SLUDGE
EFFLUENT
ANOXIC ANAEROBIC
Annual TN= 4 mg N/L with filtration
CARBON
16
Nitrify First, Denitrify with External Carbon (with Filtration)
ORGANIC
CARBON
ANOXIC AEROBIC CLARIFIER
RETURN SLUDGE
Dentrification
Activated sludge
Deep Bed
Denite filters
Biologically
activated filters
(Biostyr, Biofor)
AEROBIC CLARIFIER
RETURN SLUDGE
WASTE SLUDGE
ANAEROBIC
Annual TN= 3-4 mg N/L with filtration
Case Example – Progression from Nitrification to BNR/ENR
Step Feed Nitrifying Activated with Seasonal Nitrification Limit
• Summer: 2 mg/L NH3-N
• Winter: 5-15 mg/L NH3-N
• No P limit
• Phase 1 Upgrades
• Reduce TP to 1 mg/L
• Phase 2 Upgrades
• TP: 0.3 to 0.1 mg/L
• TN: 4 to 10 mg N/L
Phase 1 Maximized Capacity to Save $100M+
Selector Zones
Phase 1 – Reduce TP to 1.0 mg/L Results
0.0
0.5
1.0
1.5
2.0
2.5
3.0
Eff
lue
nt
TP
, m
g/L
Daily
Daily 30-DMA Annual Moving
Phase 2: Reduced Phosphorus Discharges 2A – 0.3 mg/L (Filters) 2B – 0.1 mg/L
2A
2B
Existing Nitrogen Discharges
0
5
10
15
20
25
30
35
1/1
/20
09
2/8
/20
09
3/1
8/2
00
9
4/2
5/2
00
9
6/2
/20
09
7/1
0/2
00
9
8/1
7/2
00
9
9/2
4/2
00
9
11
/1/2
00
9
12
/9/2
00
9
1/1
6/2
01
0
2/2
3/2
01
0
4/2
/20
10
5/1
0/2
01
0
6/1
7/2
01
0
7/2
5/2
01
0
9/1
/20
10
10
/9/2
01
0
11
/16
/20
10
12
/24
/20
10
1/3
1/2
01
1
3/1
0/2
01
1
4/1
7/2
01
1
5/2
5/2
01
1
7/2
/20
11
8/9
/20
11
9/1
6/2
01
1
10
/24
/20
11
12
/1/2
01
1
1/8
/20
12
2/1
5/2
01
2
3/2
4/2
01
2
5/1
/20
12
6/8
/20
12
7/1
6/2
01
2
Effl
ue
nt
Tota
l N
itro
gen
, m
g N
/L
NO3-N Ammonia-N Organic N NO2-N
Phase 2 – TN Reduction Using Influent Carbon
Monthly TN= 10 mg N/L
RAS
SI
To FST
Anoxic RAS Anaerobic
300% SI
Phase 2 - Influent Carbon for TN Reduction
Monthly TN= 10 mg N/L
Monthly TP = 1.0 mg/L
Phase 2 – Nitrify First, Denitrify with External Carbon Denite Filters
• TP < 0.3 mg/L
• TN< 4 or < 10 mg N/L
Phase 2 – Nitrify First, Denitrify with External Carbon Denite MBBR Tert. Clarifiers Membranes
• TP < 0.1 mg/L
• TN< 4 or < 10 mg N/L
Innovation
Why/How to Innovate in Our Industry?
Brown and Caldwell 28
Cost,
Energy,
Footprint Efficiency =
Wh
y H
ow
Basic
Research
Pilot-scale
Research
Pilot
BNR
Demonstration-scale
Research
Generation 1st
Sustainability
“S” Curve for Innovation
Brown and Caldwell 29
Laggards?
Late
Majority
Early
Majority
Early
Adopters
Second
Generation
De
velo
pm
en
t/N
um
be
r In
sta
lle
d
First Generation
First
Demonstration
Pilot
Time Parker’s and Roger’s “S” Curves Combined for
Status of Technology and Type of Adopter
Mature
Technology
Innovative
(Increased Risk)
Conventional
(Low risk)
Innovators
• Dixie Drain, Boise ID: P removal-water trading
• Littleton-Englewood CO: Effluent recycle for TN
• Marley Taylor WRF MD: BioMag™ process
• Nampa ID: P removal, A/O MLE, groundwater infiltrn
• St Petersburg FL: Mainstream Nitrite shunt
• Chambers Creek, Tacoma WA: Demon® sidestream N
• Minneapolis (MCES): Air Mixed Selectors
BNR Innovation Examples
Brown and Caldwell 31
• TMDL allocated point sources at 0.07 mg/L TP
• City of Boise strategy:
• Treat to ~0.5 mg/L at WWTP
• Treat agricultural return flows
• Projected cost savings: $40 million
Dixie Drain Phosphorus Trade, Boise River
Brown and Caldwell 32
Nitrified Effluent Recycle Reduces TN and Methanol Needs
Phase 2
TN Reduction
Headworks odor suppression
Methanol savings: $0.25 M/yr
Marlay Taylor WRF BioMag Process
• Clarifier SLR to 100 lb/sf-d
• Plant Capacity increased 2x-3x
• 30-40% adder to BNR energy
• ESS = 1-3 mg/L (tertiary filters)
St Petersburg Southwest Water Reclamation Facility - Nitrite Shunt
Nitrite Shunt
Brown and Caldwell 36
≈ 25% Oxygen Reduction
≈ 40% carbon and biomass reduction
Control
Parameter
Condition Action
NH4+ Control
NH4+ < 1.0 mg N/L
Reduce SRT
DO = 0.1 mg/L.
NH4+ > 3.0 mg N/L
Increase SRT
DO = 0.1 to 0.3 mg/L.
NO3- Control
NO3- > 1.0 mg N/L
Decrease DO =0.1 mg/L
Monitor NO2- accumulation in basin
NO3- < 1.0 mgN/L No action required
NO2- Control Monitor effluent NO2
- as surrogate measurement of shunt
performance
Creating Conditions for Nitrite Shunt
Southwest Water Reclamation Facility - Nitrite Shunt Operations
0
2
4
6
8
10
7/28/13 8/4/13 8/11/13 8/18/13 8/25/13 9/1/13
Nit
roge
n S
pec
ies,
mg/
L
Ammonia Nitrite Nitrate
0
1
2
3
4
5
07/28/13 08/04/13 08/11/13 08/18/13 08/25/13 09/01/13To
tal
Ph
osp
ho
rus,
mg
/L
Influent Effluent
Aeration Demands Reduced 40- 50%
• $6 million in capital & O&M savings
• Multi-process to address lack of nitrogen limits in permit
Chambers Creek – Demon® Process
Brown and Caldwell 39
Air Mixed Selectors
Air Mixed Selector – Typical Basin Profile
0
5
10
15
20
25
30
35
40
Selector End Pass
1
End Pass
2
Mid Pass
3
Selector End Pass
1
End Pass
2
Mid Pass
3
Ph
osp
ha
te, m
g P
O4
-P/L
11-Mar-15
AB-0 AB-6
AM Profile PM Profile
Air Mixed Selectors
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
1/1
/2001
7/1
/2001
1/1
/2002
7/1
/2002
1/1
/2003
7/1
/2003
1/1
/20
04
7/1
/2004
1/1
/2005
7/1
/2005
1/1
/2006
7/1
/2006
1/1
/2007
7/1
/2007
1/1
/2008
7/1
/2008
1/1
/2009
7/1
/2009
1/1
/2010
7/1
/2010
1/1
/2011
7/1
/2011
1/1
/2012
7/1
/2012
1/1
/2013
7/1
/2013
1/1
/2014
7/1
/2014
1/1
/2015
Eff
luen
t T
ota
l P
ho
sph
oru
s, m
g/L
Daily 12-Month Rolling Average
New Industry On-line
Anaerobic Digesters
Operational
Reduced DO
EBPR
Stress TestingEBPR
ImprovementsLiquid Stream and
Digester Construction
Pseudo Selector
On-line