Energy Efficiency Projects for
Aeration Systems:
• A Case Study of the Fox River
Water Reclamation District
James Kerrigan, P.E. – Fox River Water Reclamation District
Ryan Christopher, P.E. – Greeley and Hansen
Laurissa Cubbage, P.E. – Greeley and Hansen
Presentation Topics
• Overview of Energy Usage at WRF
• Overview of the Fox River Water Reclamation
District
• West WRF High Efficiency Aeration
Improvements
• Albin D. Pagorski WRF Aeration System
Improvements
• Grant Funding Availability
• Summary
Overview of Energy Usage at WRF
AERATION
54.1%
Source: Zahreddine, Phil, USEPA. “Innovative Energy Conservation Measures at Wastewater Treatment
Facilities.” Power Point Presentation.
Fox River Water Reclamation District
• Provides wastewater treatment services to
over 180,000 residents in service area (City
of Elgin, Village of South Elgin)
• FRWRD treats average of 26 MGD across 3
WRFs
– North
– West
– Albin D. Pagorski
West Water Reclamation Facility
• Online in 2004
• Design average flow 5.0
mgd
• Current average flow 3.1
mgd
• Designed for expansion
up to 25 mgd
West WRF – Aeration System
Background
• 3 Existing Multi-Stage
Centrifugal Blowers
– Blowers were oversized for
low flow situations
– Excess air was sent to offline aeration tank
• Infrastructure Available
for Denitrification
– Tanks setup for
denitrification
– Equipment purchase
required (mixers and
recycle pump)
West WRF Existing Blower Room
West WRF – Aeration Blower
Technology Evaluation
• Comparison Between Turbo Blowers and
Existing Equipment
–
–
–
–
Energy efficiency
Operation and maintenance costs
Capital costs
Payback period
• Option 1 – New Turbo Blower, continue to send excess
air to aeration tank
• Option 2 – New Turbo Blower, no excess air
• Option 3 – New Turbo Blower, no excess air and install
denitrification
Air Flow Frequency
Air Flow Frequencies
20.00%
18.00%
Option 3
16.00%
Option 2
14.00%
Option 1
12.00%
10.00%
8.00%
6.00%
4.00%
2.00%
0.00%
Evaluation Recommendation
• Recommended Option 3
– Install One 150 hp Turbo Blower and install pump
and mixers to operate denitrification
• Total Construction Cost = $177,000
• $30k in annual energy savings
• $153,318 grant was awarded from two
agencies
• 87% of construction cost for project came from grants
• Payback reduced to under 1 year with grant funding
High Efficiency Aeration Blower Project
High Efficiency Aeration Blower Project
West Plant Blower Power Reduction
– Approx. 40% Reduction in Power Usage
Old Blower
Operation
BNR Online
New Blower
Online
Albin D. Pagorski WRF
Aeration System Improvements
• Albin D. Pagorski WRF
– Daily average flow 16.0 mgd
– Design average flow 25.0 mgd
– Peak flow 50 mgd
• Existing blowers were past
useful life and have become
maintenance intensive
• No D.O. Controls, labor
intensive process
• New industrial load to plant
with high BOD concentration
ADP Aeration System Efficiency
Evaluation
• Comparison between existing equipment
and new equipment
–
–
–
–
Energy efficiency
Operation and maintenance costs
Capital costs
Payback period
• Option 1 – New Turbo Blowers
• Option 2 – New Turbo Blowers with new diffusers
• Option 3 – New Turbo Blower, with new diffusers and
D.O. controls
Air Flow Frequency
Air Flow Frequencies
20.00%
18.00%
New DO and Diffusers
New Diffusers Only
Existing Aeration System
16.00%
14.00%
12.00%
10.00%
8.00%
6.00%
4.00%
2.00%
0.00%
ADP Aeration System Improvements
• Updated Plant Basis of Design
– Analyzed plant firm capacity, resulting
reduction
• 27,000 scfm to 20,800 scfm
• Evaluated blower combinations
• New DO Control System
– Pressure Based Dual Loop Control
• Sequencing
– Minimizing WRF interruption
Blower Combination – Selected
Neuros 300 HP Option at Design Flow (25 mgd) with Fresh Express Peak Flow (0.80 mgd)
(Dirunal Variations Shown by Dashed Lines)
30,000
DAILY AVERAGE FLOW
28,000
DAILY MAXIMUM FLOW, 40% ABOVE AVERAGE
BLOWER RANGE
300HP: 2,353 to 5,369 scfm
DAILY MINIMUM FLOW, 50% BELOW AVERAGE
26,000
24,000
Firm Capacity
22,000
20,000
4-300HP
Air Flow, scfm
Maximum Flow Envelope
18,000
16,000
14,000
3-300HP
12,000
10,000
2-300HP
8,000
6,000
4,000
1-300HP
2,000
Minimum
Flow Envelope
0
0%
10%
20%
30%
40%
50%
60%
Percentile Frequency
70%
80%
90%
100%
ADP ASI – Project Update
• $2.4 million construction cost
– 5 Turbo Blowers with associated electrical
upgrades
– Dissolved oxygen control system
• Fine bubble diffusers (under separate
contract)
• Substantial Completion April 2015
• Final Completion May 2015
• Grant Funding
ADP ASI – Project Update
ADP ASI – Project Update
ADP WRF Power Reduction
Old Blowers
Operation
All New
Blowers Online
Grant Funding
• Both projects received grant funding through
ICECF and DCEO
– West WRF
• $45k from ICECF
• $108k from DCEO
– ADP Aeration System Improvements
• $208k from ICECF
• $612k from DCEO
– (Diffuser replacement required to receive full funding)
• Total Grant Funding
– $973k awarded to both projects
Summary
• Aeration system efficiency improvements can
greatly reduce operational costs
• Grant funding is available to push projects
that fight for funding with more conventional
projects
• FRWRD Projected Annual Energy cost savings
– Total = $167,400
• Simple Payback
– Under 10 years
Lessons learned
• Blower Manufacturer Differences
– Controls of blowers, valve operation
– Selected blower more cost effective even with
slightly lower efficiency
•
•
•
•
•
Integration Needs Careful Consideration
Design to Include Staging of Demolition
Staff Training
Flow Meters
New Check Valves
Questions
• Acknowledgments
– Fox River Water Reclamation District
•
•
•
•
Bob Trueblood
Beth Vogt
Doug Haacker
Dave Green
– Greeley and Hansen
• Andy Martin