lessons learned in enhanced biological phosphorus removalphosphorus (tp)… •initial effluent tp...
TRANSCRIPT
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Lessons Learned in Enhanced Biological Phosphorus Removal
87th OWEA Annual Conference
Jim Gagnon, P.E., CH2M HILL
V1.0
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Presentation Outline
Phosphorus Limits in Ohio
Upgrades to the Versailles, OH WWRF
WWRF Performance
EBPR Basics
11 Lessons Learned from Versailles
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Where is Versailles Located?
Southwestern Ohio
Darke County (borders Indiana)
43 miles north of Dayton
Population: ~2,700
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Phosphorus Limits in Ohio
Reduced in-stream phosphorus
Reduced aquatic plant growth
• Reduced in-stream
nitrogen and carbon
• Increased dissolved
oxygen
-
Impact of Stillwater River Basin 2009 TMDL Report
0.17
0.05
0
0.05
0.1
0.15
0.2
TP
(m
g/l
)
2004 TMDL
Report
2009 TMDL
Report
Ambient Target Total Phosphorus
(TP) Concentrations in Swamp Creek
For Village of Versailles…
• Point source controls
• Reduce Total
Phosphorus (TP)…
• Initial effluent TP limit of
1.0 mg/l
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Upgrades to Versailles WWRF
Project Drivers:
• Effluent Total Phosphorus Limit of 1.0 mg/l
• Reduce/Eliminate Effluent Blending
** Plant experienced 32 excess flow diversions on
average per year (2003-2007)
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Upgrades to Versailles WWRF
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Upgrades to Versailles WWRF
New Oxidation Ditch Enhances
Secondary Treatment
Features:
• Provides EBPR/BNR
capability
• Separate, dedicated
anaerobic and anoxic zones
• D.O. control of aerators
• New chemical feed system
• Room for future 2nd ditch
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Versailles WWRF Performance, or…
Let the Data Show…
0.0
1.0
2.0
3.0
4.0
2010 2011 2012 2013
3.26
2.36
0.75 0.66
TP
(m
g/l)
Average Effluent Total Phosphorus (TP) Concentration
(Through April 16)
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Enhanced Biological P Removal (EBPR) Basics
• Removal of P exceeding metabolic requirements
Enhanced Biological P Removal (EBPR)
Luxury P Removal
Excess P Removal
Bio-P Removal
• Mediated by specialized heterotrophs called
Phosphorus Accumulating Organisms (PAOs)
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Anaerobic Zone DO, NO3
Aerobic (DO)
P Release
PHB
Polyphosphate
CO2 + H2O O2
Cell
Synthesis
Energy (Ed)
Excess
P Uptake
PHB: Poly-β-hydroxybutyrate
Rapidly
Biodegradable
Substrate (VFAs)
PHB
Poly-
phosphate
Energy (Ei)
Enhanced Biological P Removal (EBPR) Mechanism
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EBPR Mechanism
Aerobic Anaerobic
• VFA uptake &
storage
• P release
• Stored ‘Food’
oxidized
• Excess P Uptake
• Cell synthesis
Waste Sludge
Loaded with P
Starving
(Battery discharging)
Feeding
(Battery charging)
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RAS
Anaerobic Aerobic
Ortho-P
3 x Infl. Ortho-P
BOD PHB
Storage
BOD Oxidized
Concentrations
in Bioreactor
Location in Bioreactor
Net P
Removal
Anaerobic/Oxic (A/O) Process Configuration
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Lesson 1: Multiple Anaerobic Zones Give PAOs Best Opportunity to Function
• Well-mixed
• Constructed walls
• Single compartment with
baffles
• Provide adequate HRT
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Lesson 2: Solids Retention Time Control Provides More Complete Picture than MLSS Control
BIOREACTOR
MLSS QINF QEFF
QWAS, CRAS
= QINF - QWAS VBIOREACTOR
VBIOREACTOR x MLSS
SRT x CRAS QWAS =
Target SRT
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EBPR
SRT NITRIFICATION
SRT
Lesson 2: Solids Retention Time Control Provides More Complete Picture than MLSS Control
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Lesson 3: Maintain Integrity of Anaerobic Zone to Promote PAO Growth
Anaerobic zone is crucial for PAO selection
Need to ensure
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Lesson 4: Maintain Low D.O. in the Aerobic Basin to Promote Denitrification
AERATOR
D.O. TRANSMITTER D.O. PROBE
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Lesson 5: Maintain Low Sludge Blankets to Limit Phosphorus in Clarifiers
TELESCOPING VALVE
SLUDGE DRAWOFF
PIPES
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• New tank volume of
640,000 gal
• Retained 3 existing
digesters
• Limit anaerobic conditions
during decant
• Decant small volumes
directly to the aerobic
zone of oxidation ditch
Lesson 6: Operate Aerobic Digester to Limit Phosphorus Release
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Lesson 7: Use ORP to Monitor Aerobic Digester
DIGESTER ORP AND
D.O. PROBES WITH
FLOAT
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Lesson 8: Monitor and Handle Wet Weather Flows to Maintain EBPR
• Wet weather flows:
Dilute in substrate
Higher in DO
• Existing ditch and
clarifiers reused to
provide wet weather
storage
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Lesson 9: Prepare for Excursions
• Adsorption
• Ion exchange
• Membrane filtration
• Filtration
• Enhanced (ballasted)
sedimentation
• Chemical addition
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Lesson 9: Prepare for Excursions
ALUM STORAGE ALUM DOSING POINT –
OXIDATION DITCH
EFFLUENT WEIR
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Lesson 10: Maintain Records and Use Data to Understand How EBPR is Operating
Influent:
Volume, D.O., pH, SS, CBOD5, NH3
Bioreactor:
D.O., pH, MLSS, SVI, MLVSS, F/M
Return Sludge:
pH, SS, Volume Wasted, % Solids, % VS
Effluent:
pH, D.O., NH3, SS, CBOD5, TN, TP
Digesters:
% solids, % VS
Digester Supernate:
NH3, CBOD5, ORP, TP, Volume
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Lesson 10: Maintain Records
0
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WA
S o
r D
EC
AN
T (
ga
llo
ns)
SR
T (
da
ys
) o
r To
tal-
P (
mg
/l)
WAS
TARGET SRT = 20 DAYS
March 2013 Data
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Lesson 10: Maintain Records
0
2,000
4,000
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ar
WA
S o
r D
EC
AN
T (
ga
llo
ns)
SR
T (
da
ys
) o
r To
tal-
P (
mg
/l)
WAS SRT-7DMA
TARGET SRT = 20 DAYS
March 2013 Data
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Lesson 10: Maintain Records
0.29 0.52 0.97 0.46 0
2,000
4,000
6,000
8,000
10,000
12,000
0
5
10
15
20
25
1-M
ar
2-M
ar
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ar
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ar
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ar
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ar
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ar
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ar
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ar
27-M
ar
28-M
ar
29-M
ar
30-M
ar
31-M
ar
WA
S o
r D
EC
AN
T (
ga
llo
ns)
SR
T (
da
ys
) o
r To
tal-
P (
mg
/l)
WAS Total-P SRT-7DMA
TARGET SRT = 20 DAYS
March 2013 Data
-
Lesson 10: Maintain Records
0.29 0.52 0.97 0.46
0
10,000
20,000
30,000
40,000
50,000
60,000
70,000
80,000
90,000
100,000
0
5
10
15
20
25
1-M
ar
2-M
ar
3-M
ar
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ar
5-M
ar
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ar
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ar
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ar
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ar
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ar
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ar
25-M
ar
26-M
ar
27-M
ar
28-M
ar
29-M
ar
30-M
ar
31-M
ar
WA
S o
r D
EC
AN
T (
ga
llo
ns)
SR
T (
da
ys
) o
r To
tal-
P (
mg
/l)
WAS Total-P SRT-7DMA
TARGET SRT = 20 DAYS
March 2013 Data
-
Lesson 10: Maintain Records
0.29 0.52 0.97 0.46
0
10,000
20,000
30,000
40,000
50,000
60,000
70,000
80,000
90,000
100,000
0
5
10
15
20
25
1-M
ar
2-M
ar
3-M
ar
4-M
ar
5-M
ar
6-M
ar
7-M
ar
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ar
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ar
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ar
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ar
30-M
ar
31-M
ar
WA
S o
r D
EC
AN
T (
gallo
ns)
SR
T (
da
ys
) o
r To
tal-
P (
mg
/l)
WAS DECANT Total-P SRT-7DMA
TARGET SRT = 20 DAYS
March 2013 Data
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Lesson 11: Develop a “TP Compliance Strategy” to Ensure Permit Limits are Achieved
Obtain 24-hr composite effluent sample and measure Ortho-P.
Is
Ortho-
P
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In Conclusion…
• EBPR in Ohio is relatively new and becoming
more common
• New requirements require effective management
of the treatment process to achieve permit limits
• Operators can use their existing knowledge
• Designers must provide flexibility
• Approach the process as a full-scale laboratory…
Allows for new ideas and for hands-on
optimization
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Questions?
513-587-7078
Lessons Learned in Enhanced Biological Phosphorus Removal