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Dynamic Process Modeling for Managing Energy Efficiency
Michigan Water Environment Association Annual Conference
June 19, 2017
Richard Beardslee, City of Battle CreekKendra Sveum, Donohue & Associates
Outline
• Battle Creek WWTP
– Energy Evaluation
– Control Strategy
• Stickney WRP
– Energy Evaluation
– Blower Operation
Acknowledgements
Battle Creek WWTP
• M&R
• M&O
• inCTRL Solutions, Inc.
• Carol Naughton & Associates
• EnvironmentalDesign International, Inc.
MWRDGC
• Rich Beardslee
• Chris Dopp
• Carl Fedders
• Kurt Tribbett
• Perry Hart
• Marvin Krause
• Bryan Crawford
• Chris Pratt
Battle Creek Background
Background: Battle Creek
Design capacity 27 mgd
Currently operating at 9 mgd
Significant loadings from food processors and paper
Influent BOD
• 580 mg/L (2013-2014)
• 650 mg/L (2015)
Page 5 | November 12, 2015MWEA
Background: Battle Creek
Page 6 | November 12, 2015MWEA
Process Type: Single-Stage Activated Sludge with Nitrification
Background: Battle Creek
Background: Battle Creek, MI
• Project Drivers
– Energy conservation
– Aged facilities: Blowers cannot be repaired
– Aged facilities: Outdated aeration control
– Process Improvements: Nutrient deficiency issues
– Chemical Savings: Phosphorus control
Battle Creek Evaluation
Dynamic Evaluation
0
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45,000
50,000
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01
4
Air
flo
w (
scfm
)
Airflow Required Airflow Supplied
Blowers
Blower Information New TurboExisting
CentrifugalNo. of Blowers 4 2Firm Capacity 4 1Motor Size (Hp) 350 1000Voltage (V) 480 4160Turndown Method VFD Inlet ThrottlingMaximum Flow (scfm) 7,500 21,000Minimum Flow (scfm) 3,500 13,000
Blower Information Centrifugal PDNo. of Blowers 3 3*Firm No. of Blowers 2 3Motor Size (Hp) 1000 450Manufacturer Hoffman SutorbiltVoltage (V) 4160 460Turndown Method Inlet Throttling NoneMaximum Flow (scfm) 21,000 7,000Minimum Flow (scfm) 13,000 7,000
Operating Range
Remaining centrifugal blower capacity
New turbo blower capacity
Power Comparison
0
5,000
10,000
15,000
20,000
25,000
30,000
35,000
40,000
45,000
50,000
kWh
57% Reduction in Energy
Ammonia-Based DO Control
Controlling Rate of Nitrification with Ammonia-Based DO Control
0
2
4
6
8
10
12
NH
3 (
mg/
L)
NH3 Control DO Control
Beginning of Tank End of Tank
Conceptual Example
Ammonia-Based DO Control
Controlling Rate of Nitrification Based on DO Concentration
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0
Nit
rifi
er
Gro
wth
Rat
e (
Re
lati
ve o
t M
ax R
ate
)
Dissolved Oxygen (mg/L)
Significant impact on growth rate over potential range of DO concentrations
Ammonia Control Loop v2
Blowers
FIT
PIT
DO
DO Control with Air Header Pressure Based Blower Control
To Other Tanks/Passes
Pressure Control Loop
Pass 1
Pass 2
DO Ammonia
DO Control Loop
Ammonia Control Loop
DO Setpoint(s) automatically adjusted to maintain ammonia
concentration setpoint Operator Input: Ammonia Setpoint
Control Clamp: Min/Max Airflow
Ammonia-Based DO Control
Controlling Rate of Nitrification with Ammonia-Based DO Control
0
2
4
6
8
10
12
NH
3 (
mg/
L)
NH3 Control DO Control
Goal Range
For This Example
Slowly Decrease
DO SetpointUntil AmmoniaReading is in
Desired Range
Beginning of Tank End of Tank
Conceptual Example
Probe
Stickney WRP Background
Stickney WRP
Average Primary Effluent
Flow: 787 mgd
BOD5: 155 mg/L
NH3-N: 17 mg/L
TP: 7.67 mg/L
• Average Secondary Effluent
– BOD5: 7.74 mg/L
– NH3-N: 0.57 mg/L
– TP: 1.4 mg/L
– TSS: 5 mg/L
Whole Plant Model
Stickney Evaluation
Aeration System Model
Air Demand Distributions
0
100,000
200,000
300,000
400,000
500,000
600,000
700,000
0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%
Air
flo
w (
scfm
)
Total Airflow Data DO Control Ammonia Control
Aeration Blowers
Blower Number Type
Min(psig)
Max(psig)
Min(scfm)
CurrentMin
(scfm)Max
(scfm)
4 - 7 Axial Flow 7.1 8.1 165,000 210,000 244,000
3 Centrifugal - - 39,000 - 75,000
2* Centrifugal 7.1 8.1 92,500 - 186,000
Blower Operating Ranges
Dynamic Process Modeling for Managing Energy Efficiency
Michigan Water Environment Association Annual Conference
June 19, 2017
Richard Beardslee, City of Battle CreekKendra Sveum, Donohue & Associates
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