a presentation for americas authority in membrane technology first year of operational experience at...
TRANSCRIPT
A PRESENTATION FOR
America’s Authority in Membrane Technology
First Year of Operational Experience at Tennessee's Largest Membrane Filtration Plant
KYTN Water Professionals ConferenceNashville, Tennessee
July 19, 2010
Overview
• Background• Design Considerations• Construction• Operation• Costs of Treatment• Summary and Conclusions• Questions
Background
• Stones River Water Treatment Plant○ Built in 1969, Expanded in 1980○ Capacity of 15.67 MGD○ Lime Softening○ Mixed Media Filtration○ Gaseous Chlorine
Disinfection
Background
• Project Objectives○ Add Membranes to Treatment○ Expand Capacity to 20 MGD○ Chemical Feed Replacement○ Additional Clearwell Storage○ New High Service Pumping○ Renovate Filters for GAC
Design Considerations
• New Test Developed to Estimate Flux
Murfreesboro MPI=0.03
Design Considerations
Pilot Testing Results
• Stable Performance at 87.5 gfd for 2 months• Stable Performance at 120 gfd for 1 week• Stable Performance at 99% Recovery for 2 weeks• Stable Performance w/o EFM for 1 week• Easy Removal of Polymer Fouling• 99.5% Permeability Recovery
Design Considerations
Membrane Design Criteria
• Design Flux- 87.5 gfd @ 95% Recovery• Design Temperature- 4 deg Celcius• Cleaning Interval- Once/month• Enhance Flux Maintenance- Once/day• Membrane Warranty- 10 Years Prorated
○ Irreversible Loss of Permeability >15%○ Fiber Breakage >0.2%
Pre-Construction
Construction
Construction
Completion
Turbidity
Turbidity
pH
Hardness
Alkalinity
TOC Removal
TOC Removal
Average Raw
Average Filtered
Average % Removal
Before Membranes Installed 3.01 1.93 35.83
After Membranes Installed 3.57 2.02 43.47
After GAC Installed 3.03 1.59 47.46
Quarterly DBPs
Daily TTHMs
Operation
• Operated one Rack at Design Flux for one year
• Turbidity Excursion• Fouling on Rack 6• Issues with Cleaning regime • Fiber Breakage
Typical Month- Rack 2
Typical Month- Rack 2
Typical Month- Rack 6
Typical Month- Rack 6
Turbidity Excursion- Rack 2
Turbidity Excursion- Rack 2
Turbidity Excursion- Rack 6
Turbidity Excursion- Rack 6
Cleaning Issues- Rack 2
Cleaning Issues- Rack 2
Cleaning Issues- Rack 6
Cleaning System Issues
• Programming Issues• Hypochlorite Solution Strength was low• Water Temperature was low • Recirculation Time insufficient• EFMs had been suspended
Chemical Costs
Chemical Unit Prices
Chemical Costs
Chemical Costs
Coagulant Costs
Post Treatment Chemicals
Membrane Cleaning Chemicals
Electric Costs
Electric Costs
Power Analysis
Static Strainer
Static Strainer
Static Strainer
Static Strainer
Fiber Breakage
• Total Number of Fibers- 3,125,000• Total Number of Fiber Breaks in Year 1= 5
○ All five were in two modules in one rack in one day
• Percentage of Breakage- 0.00016%• Percentage of Breakage in affected 2
modules= 0.04%• San Patricio – 0.00030% over 5 years
GAC Effervescence
GAC Effervescence
• Potential Causes○ Temperature Change and DO Saturation○ Leak in Air Scour System○ Air in GAC Effluent Line○ Biological Activity○ Air in Membrane Permeate Header
GAC Effervescence- Actual Cause
Summary and Conclusions
• Evaluate All Costs and Design Considerations of Membrane System When Evaluating
• Lime Softening is an Excellent Pretreatment for Membranes
• Membrane Warranty Should Define a Failure According to Fiber Breakage and Irreversible Fouling
• Verify the Effectiveness of Every Clean
• Membranes Are a Great Tool, Not a Magic Bullet
Acknowledgements
