A PRESENTATION FOR Americas Authority in Membrane Technology First Year of Operational Experience at Tennessee's Largest Membrane Filtration Plant KYTN Water Professionals Conference Nashville, 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 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 % 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
Completion
Turbidity
pH
Hardness
Alkalinity
TOC Removal
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 6
Turbidity Excursion- Rack 2
Turbidity Excursion- Rack 6
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
Coagulant Costs
Post Treatment Chemicals
Membrane Cleaning Chemicals
Electric Costs
Power Analysis
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 % Percentage of Breakage in affected 2 modules= 0.04% San Patricio – % over 5 years
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
Questions? Mike Bernard, PE (615)