providing infrastructure redundancy at the rocky river wwtp
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Providing Infrastructure Redundancy at the Rocky River WWTP
Timothy McCann – AECOM
Keith Bovard – Rocky River WWTP
Redundancy
• As NASA Would Say:
“A Backup Plan for the
Backup Plan”
• Nuclear Power Plant
• Wastewater Treatment
Plant
October 25, 2012 Providing Infrastructure Redundancy
at the Rocky River WWTP Page 3
Infrastructure Redundancy
• Infrastructure Redundancy
Neglected in Early WWTPs
• Incorporated in New
Construction and
Rehabilitation
• Redundancy May or May
Not be Part of Normal
Operations
• Includes Piping, Tanks,
Channels, etc.
October 25, 2012 Providing Infrastructure Redundancy
at the Rocky River WWTP Page 4
Driving Forces for Redundancy
October 25, 2012 Providing Infrastructure Redundancy
at the Rocky River WWTP Page 5
Maintenance and Operation
Efficiency 38%
Regulations 29%
Emergency/ Disaster Planning
12%
Design Guidelines
21%
• Efficient Redundancy
Design Practices, 2003
• Survey of 46 Treatment
Facilities
Jank, Palmer, Ross 2003
Infrastructure Redundancy Benefits
• Reduced Downtime
• Meet Regulations
– Avoid Bypasses
– Provide Required Treatment
• Savings on O&M
– Avoid Maintenance Issues
• Increased Plant Operation
Efficiency
• Overall Cost Effectiveness
October 25, 2012
Providing Infrastructure Redundancy
at the Rocky River WWTP Page 6
Additional Redundancy Measures
• Backup or Standby
Equipment
– Pumps, Screening
• Spare Parts On-hand
• Instrumentation
Redundancy or Backup
Measures
– Sensors, Analyzers
• Emergency Contracts
– Sludge Disposal, Pumping
October 25, 2012 Providing Infrastructure Redundancy
at the Rocky River WWTP Page 7
Redundancy – 10 States Standards
• Sec. 53.6 – Arrangement of
Units
– Arrange units for O&M
convenience
– Flexibility and ease of
installation of future additions
– Continuous quality effluent
– Economical additions
• Sec. 54.2 – Unit Bypasses
– Maintenance & emergencies
– Maintain effluent quality
October 25, 2012 Providing Infrastructure Redundancy
at the Rocky River WWTP Page 8
Headworks and Preliminary Treatment
• Screening
• Grit Removal
• Equalization Tank
• Bypass Alternatives
• Redundancy or Backup
Measures
October 25, 2012 Providing Infrastructure Redundancy
at the Rocky River WWTP Page 9
Primary Treatment
• Primary Clarifiers
– Additional Tanks
– Replacement Equipment
• Influent & Effluent
Channels and Pipes
• Chemical Feed
– Storage
– Pumping
October 25, 2012 Providing Infrastructure Redundancy
at the Rocky River WWTP Page 10
Secondary Treatment
• Biological Treatment Tanks
– Additional Tanks
– Backup Equipment
• Bypass Channels and
Pipes
• Sludge Lines
• Secondary Clarifiers
October 25, 2012 Providing Infrastructure Redundancy
at the Rocky River WWTP Page 11
Advanced Treatment
• Bypass Channels and
Pipes
• Nutrient Removal
– Nitrogen
– Phosphorus
• Filtration
• Process Tanks
• Equipment
October 25, 2012 Providing Infrastructure Redundancy
at the Rocky River WWTP Page 12
Disinfection
• Bypass Channels and
Pipes
• Process Tanks
• Chemical Feed
• UV
October 25, 2012 Providing Infrastructure Redundancy
at the Rocky River WWTP Page 13
Solids Processing
• Digester Tanks
• Storage Tanks
• Bypass Piping
• Dewatering
• Gas Handling
• Disposal
October 25, 2012 Providing Infrastructure Redundancy
at the Rocky River WWTP Page 14
WWTP Infrastructure Redundancy
• What Works Best for YOU?
– Rotate Equipment
– Use Tanks, Channels as Part
of Normal Operations
– Emergency Use Only
• Tailor to Each Individual
Plant
• Operator Experience
– What Will Work?
– What is Needed?
• Engineering Guidance
October 25, 2012 Providing Infrastructure Redundancy
at the Rocky River WWTP Page 15
Rocky River WWTP Information
• Serves 4 Communities
– Bay Village
– Fairview Park
– Rocky River
– Westlake
• Design Flow: 22.5 MGD
• Average Flow: 12.5 MGD
• Peak Influent Flow: 170
MGD
– February 2011
– All Flow Through Bar Screens
• Submerged Outfall
October 25, 2012 Providing Infrastructure Redundancy
at the Rocky River WWTP Page 20
1937 Plant Description
• Grit Chamber
• Settling Tank
• Anaerobic Digestion
• Sludge Drying Beds
• Discharge to Spencer Creek
• Provided Capacity & Function Until 1960s
October 25, 2012 Providing Infrastructure Redundancy
at the Rocky River WWTP Page 22
1961 Plant Modifications
• Additional Screening & Comminutor
• Aerated Grit Removal
• Chemical Coagulant Feed
• Primary Clarification
• Effluent Chlorination
• Submerged Outfall to Lake Erie
• Sludge Thickeners and Anaerobic Digesters
• Vacuum Filtration and Sludge Incinerator
October 25, 2012 Providing Infrastructure Redundancy
at the Rocky River WWTP Page 26
1961 Construction Photos
October 25, 2012 Providing Infrastructure Redundancy
at the Rocky River WWTP Page 27
1961 Construction Photos Cont.
October 25, 2012 Providing Infrastructure Redundancy
at the Rocky River WWTP Page 28
1975 Plant Modifications
• Ohio Water Pollution Control Board
– 1965 – Required Secondary Treatment
– Average Flow: 10 MGD
– Peak Flow:20 MGD
• Granular Activated Carbon Filtration & Adsorption
• Added Settled Sewage Pump Station to Carbon Facility
• Additional Minor Upgrades
• Carbon Treatment Operated Less than One Year
October 25, 2012 Providing Infrastructure Redundancy
at the Rocky River WWTP Page 31
Current Plant
• Added four Fixed Film
Reactors & Final Clarifiers
• Chlorine Contact Tanks
• Modified Settled Sewage
Pump Station
– 45 MGD Capacity
– Four 15 MGD Pumps
– 42-inch Force Main to Reactor
Building
• Additional Clarifier Tanks
October 25, 2012 Providing Infrastructure Redundancy
at the Rocky River WWTP Page 34
Settled Sewage Pump Station
• Pumps Primary Treated
Wastewater to Secondary
Treatment
• Wet Well - Converted
Chlorine Contact Tank
• Rehabbed Carbon Column
Treatment Pump Station
• Flow from Primary
Clarifiers and Auxiliary
Clarifiers
October 25, 2012 Providing Infrastructure Redundancy
at the Rocky River WWTP Page 36
Plan View – Before Project
October 25, 2012 Providing Infrastructure Redundancy
at the Rocky River WWTP Page 37
Section View – Before Project
October 25, 2012 Providing Infrastructure Redundancy
at the Rocky River WWTP Page 38
SSPS Backup Project Purpose
• All Flow to Secondary
Treatment is through
Existing Force Main
• Potential Issues with Pump
Station – No Secondary
Treatment
– Pump Failure
– Force Main Failure
– Wet Well Issues
October 25, 2012 Providing Infrastructure Redundancy
at the Rocky River WWTP Page 39
SSPS Potential Additional Issues
• Prevent Permit Violations
• Die-off of Microorganisms
at Reactors
• Associated Odor Problems
(Proximity to Houses)
• Start-up Timeframe for
Reactor Activity
• Consequent Sludge
Volume Wash-out
October 25, 2012 Providing Infrastructure Redundancy
at the Rocky River WWTP Page 40
SSPS Backup – Alternative #1
Submersible Pumps in Wet Well
• Redundant Pump Capacity
– Two Submersible Solids Handling Pumps
– 15 MGD @ 80 feet TDH each
• Use Existing Force Main
• Simple Modification
– Existing station remain online
– No gates required
• Interfere with Normal Operating Conditions
– Must be stored somewhere else onsite
October 25, 2012 Providing Infrastructure Redundancy
at the Rocky River WWTP Page 41
SSPS Backup – Alternative #2
Redundant Pump Station
• New Pump Station
– Two Vertical Turbine Pumps
– 15 MGD @ 80 feet TDH each
• Use Existing Force Main
• New Wet Well Collection Box
• Stop Plates in Wet Well
October 25, 2012 Providing Infrastructure Redundancy
at the Rocky River WWTP Page 43
SSPS Backup – Alternative #3
Redundant Pump Station and Force Main
• New Pump Station
– Two Vertical Turbine Pumps
– 15 MGD @ 80 feet TDH each
• Construct New Force Main
• New Wet Well Collection Box
• Operation Flexibility
October 25, 2012 Providing Infrastructure Redundancy
at the Rocky River WWTP Page 45
Alternative #3 Continued
October 25, 2012 Providing Infrastructure Redundancy
at the Rocky River WWTP Page 47
SSPS Backup – Alternative #4
Contract Pumping Service
• Contract with Pump Rental Company
• Rent 30 MGD Pumping Capacity
– Pumps running and installed within 24 hours
– Full capacity within one week
• Run Temporary Force Main to Reactor Building
• Construct Permanent Piping at Reactor Building
October 25, 2012 Providing Infrastructure Redundancy
at the Rocky River WWTP Page 48
SSPS Backup – Alternative #5
Temporary Pumps and Wet Well Partition
• Similar to Alternative #4
• Contract with Pump Rental Company
• Rent 30 MGD Pumping Capacity
– Pumps running and installed within 24 hours
– Full capacity within one week
• Run Temporary Force Main to Reactor Building
• Construct Permanent Piping at Reactor Building
• Install Partition Gates in Wet Well
October 25, 2012 Providing Infrastructure Redundancy
at the Rocky River WWTP Page 49
Cost Comparison
$1,649,000
$3,127,000
$3,958,000
$655,000 $414,000
$0
$500,000
$1,000,000
$1,500,000
$2,000,000
$2,500,000
$3,000,000
$3,500,000
$4,000,000
$4,500,000
Alt. 1-Submersible
Pumps
Alt. 2-Backup Pump
Station
Alt. 3-Backup Pump
Station andForce Main
Alt. 4-Contract
Pumping Service
Alt. 5-Contract
Pumping & WetWell Partition
Alternative Cost Analysis
October 25, 2012 Providing Infrastructure Redundancy
at the Rocky River WWTP Page 51
Alternative Selection
• Selected Alternative #5
• Bypass Pumping Used
– Lift station rehabilitation in
case of lift station
malfunctioning, failure or force
main rupture.
• Bypass Work Accomplished
with Centrifugal Pumps
October 25, 2012 Providing Infrastructure Redundancy
at the Rocky River WWTP Page 52
Bypass Pumping Design
• Pump Capacity
– 35 MGD
• Piping Layout
• Permanent Pipe Design
• Flap Gate
• Picture of Permanent
October 25, 2012 Providing Infrastructure Redundancy
at the Rocky River WWTP Page 53
Design Project – Wet Well Modifications
• Added Slide Gates to Wet
Well
• Dividing Wall Slide Gate
• Additional Channel Gate
October 25, 2012 Providing Infrastructure Redundancy
at the Rocky River WWTP Page 54
Additional Project Items
• Overflow Meter
• Pipe Painting
• Additional Level Sensors
– Split Wet Well
– SCADA Integration
October 25, 2012 Providing Infrastructure Redundancy
at the Rocky River WWTP Page 55
Ohio EPA Project Notification
• Preventative Backup System
• Purpose: Maintain Flow to Secondary Reactors in the
Event of a Failure to:
– Primary effluent pump station
– 42-inch force main.
• No Change to Treatment System
• Low Bidder: $650,000
October 25, 2012 Providing Infrastructure Redundancy
at the Rocky River WWTP Page 56
Permanent Pipe Construction
• Enable Connection of
Temporary Pipe at Ground
Level
• Empty into Reactor
Building Wet Well
• Multiple 18-inch
Connections with Knife
Gate Valves
October 25, 2012 Providing Infrastructure Redundancy
at the Rocky River WWTP Page 58
Bypass Pumps & Piping
• Dry Prime
– 6 Pumps – 7 MGD Each
• Welded HDPE Pipe
– 3-18” Pipes to Reactors
– Pipe Header
• Air Relief Valves
• Drain Lines
• Knife Gate Valves
• Check Valves
October 25, 2012 Providing Infrastructure Redundancy
at the Rocky River WWTP Page 59
Wet Well Preparation & Utilization
• Temporary Bulkhead
Portion of Wet Well
• Maintain Flow to Portion of
Wet Well for Bypass Pump
Intakes
• Allow Installation of Wet
Well Gates & Dividing Wall
October 25, 2012 Providing Infrastructure Redundancy
at the Rocky River WWTP Page 60
Wet Well Slide Gates & Divider Wall
• Divider Wall Construction
• Three New Slide Gates
• New Level Sensors
– Used Existing Conduit &
Spare Wiring
October 25, 2012 Providing Infrastructure Redundancy
at the Rocky River WWTP Page 61
Operations During Construction
• Equipped with Alarms to
Notify Operations Staff of
Unit Failure or Loss of
Power.
• SCADA
• Wet Well Levels and
Transformer Availability
• VFD Performance
• Pump Pressure
October 25, 2012 Providing Infrastructure Redundancy
at the Rocky River WWTP Page 62
Current Availability in Case of Emergency
• Some after-Project
equipment and materials
maintained onsite.
• Line item Budget reserved
for Emergency Contracts.
• Proposals received for
projected use of pumps
and piping equipment.
October 25, 2012 Providing Infrastructure Redundancy
at the Rocky River WWTP Page 63
Construction Challenges
• Permanent Pipe Pad
– Existing Unknown Duct Bank
• Permanent Piping
– Modification for New Flange
– Air Release
• Electric or Diesel Pumps?
• Wet Well Temporary
Bulkhead
• Noise & Spill Containment
• Bypass Demobilization
October 25, 2012
Providing Infrastructure Redundancy
at the Rocky River WWTP Page 64
Current Backup Systems
• Dual Primary (Single-stage) Digesters and Mixers, Thickeners and Sludge Heaters
• Two Belt Filter Presses, Polymer Systems, and Associated Feed And Washwater/Filtrate/Sump Pumps
• Pump Station Galleys with Multiple Pump and Piping Configurations
• Chemical Storage Tanks and Pumps
October 25, 2012 Providing Infrastructure Redundancy
at the Rocky River WWTP Page 66
Potential Future Redundancy
• Digestion
– Sludge Screening
– Storage Tanks
• Storm Tank Dewatering and Sludge Piping
• Additional Chemical Piping
• Water Main and Plant Circulation Piping
• Backup Generator
– Currently Second Power Source
October 25, 2012 Providing Infrastructure Redundancy
at the Rocky River WWTP Page 67
References
Janks B., Palmer T., Ross M. 2003. Efficient Redundancy Design Practices.
Alexandria, VA: Water Environment Research Foundation.
2004. Recommended Standards for Wastewater Facilities. Albany, NY: Wastewater
Committee of the Great Lakes--Upper Mississippi River Board of State
and Provincial Public Health and Environmental Managers
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