AEP Water/Wastewater SeminarDelphos, Ohio
May 25, 2016
Michael Atherine, P.E.
Senior Managing Principal
I. Original Wastewater System Overview
II. Problems / Issues Encountered
III. Evaluation Process
IV. Selected Replacement Process
V. Comparison – Original vs. Replacement
Wastewater Treatment Overview
Original WWTP
Original WWTP
• Membrane Bioreactor Technology
• Constructed 2005/2006
• Construction Cost - $32 Million
• Average Day Design Capacity – 3.83 MGD
• Peak Day Capacity – 12.0 MGD
• Design Population Equivalent – 70,000
• Number of Bioreactor Trains – 5
• Flat Plate Membrane Plates Per Train – 10,400
• Total Number of Flat Plate Membranes – 52,000
• Largest Flat Plate Membrane Bioreactor Facility in the World at Time of Construction
Original MBR Trains
Original MBR Schematic
Membrane Cassettes
Membrane Unit
Membrane Plate
Membrane Blowers
Wastewater Treatment Plant Issues
• Fouled-Failed Membranes/Reduced Plant Capacity
• Blower Failures/Common Air Header
• Blower Turn-Down Flexibility
• High Electric Power Consumption Associated with Membrane Bioreactor Process ($400,000 Annually)
• Influent Raw Sewage Screening
• Hydraulic Flow
• Peak Wet Weather Flow
Fouled Membrane Cassette
Fouled Membrane
Membrane Replacement Evaluation Process
• Replacing with same membrane ruled out due to both high membrane cost ($6,000,000+/-) and high annual power cost ($400,000)
• Evaluated ten (10) different membrane types including flat plate, hollow fiber and a combination of flat plate and hollow fiber.
• Also evaluated converting to a non-membrane conventional-type wastewater treatment process.
• Membrane replacement evaluation team consisted of two (2) City Administrative Staff, four (4) City Plant Operational Staff and PDG.
• Presentations given by manufacturers of the eleven (11) replacement options to evaluation team.
Membrane Replacement Evaluation Process
• Short-listed four (4) membrane manufacturers/types• Two (2) manufacturers of hollow fiber membranes
• Flat plate membrane
• Hybrid hollow fiber/Flat plate membrane (new on market)
• Detailed presentation including cost from each short-listed manufacturer/membrane type
• Evaluation also included non-monetary criteria:
• Equipment reliability• Fouling potential• Experience• Manufacturer’s team• References contacted
• Operability• Handling peak flows• Cleaning requirements• Owner preference
Non-Monetary Evaluation CriteriaType of Impact Weight Value Impact Vale Total
1. Equipment Reliability 5
a. Ease of Replacementb. Cleaning Frequencyc. Fouling Potentiald. Warranty
2. Experience 3
a. No. of Larger Installationsb. Manufacturer’s Teamc. No. of Years in Service
3. References 3
a. Contactsb. List of Plants in Operations
4. Operability 5
a. Handle Peak Wet Weather Flowb. Automated Cleaningc. No. of Membranes
5. Owner Preference 5
Weight Value1 – Minimal Importance3 – Important5 – Very Important
Impact Value1 – Minimal Rating or Beneficial Impact3 – Average Rating or Beneficial Impact5 – Significant Rating or Beneficial Impact
Cost Comparison Summary
Membrane Replacement Type
Hybrid Hollow Fiber/Flat Plate
Hollow FiberType 1
Hollow FiberType 2
Flat Plate
No. of Membrane Trains 4 4 3 3
Equipment Cost $2,687,000 $2,828,000 $3,025,000 $4,740,000
Blower Annual Power Cost $80,000 $85,000 $102,000 $236,000
Note: Existing Annual Power Cost: $400,000 +/-
Non-Monetary Evaluation Summary
Membrane Replacement Type
EvaluatorHybrid Hollow Fiber/Flat Plate
Hollow FiberType 1
Hollow FiberType 2
Flat Plate
City 1 114 120 88 37
City 2 116 104 78 57
City 3 105 99 81 36
City 4 83 96 81 33
City 5 107 102 81 44
City 6 111 98 76 31
PDG 94 92 68 34
Selected Membrane Replacement
• Based on both monetary and non-monetary criteria, the hybrid hollow fiber / flat plate membrane as manufactured by Fibracast, was the selected membrane replacement process.
Membrane Replacement Process
Fibracast Membrane Cassette
Fibracast Membrane Demo Train
Full Build-Out Schematic
Membrane Replacement Process
Comparison – Original vs. Replacement
ItemExisting Membrane
SystemReplacement Membrane
System
Membrane Trains 5 3
Membrane Cassettes 130 12
Membrane Units 52,000 16,128
Actual Monthly Avg. Power Usage (kWh) 531,600* 237,400**
* Based on 2015 power usage at 0.8 to 1.0 MGD** Based on February, March & April 2016 Replacement System at 1.2 MGD