Improved Membrane Design Addresses Integrity Issues for the City of Yuba City Water Treatment Plant

Transcription

1 Improved Membrane Design Addresses Integrity Issues for the City of Yuba City Water Treatment Plant Richard Stratton, PE HDR Engineering

2 Acknowledgements City of Yuba City - John Westhouse, Plant Supervisor - Terrance Pioro, Chief Plant Operator

3 Yuba City Facts Founded in 1849 Population 65,000 Located in Sutter County along Feather River - 43 miles north of Sacramento Major Area Employers: Sunsweet, Beale AFB

4 Water Demand Projections Based on annual average demand of 273 gpc/day Year 2012 Buildout MGD Average Max Annual Day Peak Hour MGD Average Annual Max Day Peak Hour

5 Feather River Water Source High turbidity (> 200 NTU) during winter storm events Low turbidity (<5 NTU) during summer Taste and odor episodes during low flows (fall)

6 Source Water Quality Used for Membrane Design Summer (May to October) Winter (November to April) Parameters Range 95 th Percentile Range 95 th Percentile Temperature, ºC Turbidity, NTU TOC, mg/l ph Alkalinity, mg/l as CaCO Hardness, mg/l as CaCO

7 Submerged Membrane Selected Because: Best use of existing infrastructure Lowest life-cycle costs Best planning for future regulatory impacts Compatibility with existing treatment processes

8 Submerged Membrane Design Designed around two suppliers: - USFilter/Memcor CMF-S (Siemens) - Zenon Zeeweed 1000 (GE) Competitive Bidding: - Present worth worksheet - Overall project cost Pilot Testing - After membrane selection - Prior to fabrication to confirm bid assumptions Two cells 6 mgd capacity each

9 Memcor CMF-S (Siemens) System Accepted in 2008 Lime PAC Alum PACl CLS Flocculation Basin Membrane Filter Lime CLS HFA Raw Water Low Lift Pumps PACl Alum Lime PAC CLS Inline- Mix Rapid- Mix Screens Flocculation/ Sedimentation Basin Pol Dual- Media Filter Clearwell Process Flow Schematic Distribution High Service Pump

10 Key Map Layout Mixer CIP and Backwash Area Screens Future Membrane Filters Flocculation Basins Membrane Channel and Basins

11 Pretreatment Varied by Season Mixer : Summer Flocculation Only Five minutes contact time for Alum and PAC Provide equalization volume for backwashing Winter Use existing flocculation and sedimentation basins

12 Rapid Mix & Screening Rapid mix using submersible highspeed mixer Dual flow band screening (2 mm) to remove solids that may pass through flocculation or sed basins

13 Submerged Membrane System Membrane in Concrete Basins Permeate Pumps and Piping in Filter Gallery

14 Membrane Maintenance Provisions Covers Air Test System Bridge Crane

15 Operations Summary BW 30 minutes interval, 3 minutes duration MW 96 hours interval, 40 minutes duration CIP 30 days interval, 5 hours duration Filtrate Turbidity 0.04 NTU (avg.) Feed Turbidity < 10 NTU (avg.) Water Recovery 97.0% (avg.) TMP 8.5 psi (avg.) Flux 30.9 gfd (avg.) LRV Always > 4.0; typical 4.5 Permeability, gfd/psi@ 20 deg C Initial 10.0; End of 30 days 7.5

16 Membrane Performance with PAC Addition

17 Membrane Test Performance with PAC Addition

18 Membrane Permeability Performance* Permeability, gfd/psi Jan Feb Mar Apr May Jun Jul * Measured after CIP, corrected to 20º C

19 First Two Years of Operation Summary Membrane permeability remained high Treated water quality was excellent Pressure decay test values began to rise and log removal values fell Membrane integrity issues became a concern and Memcor was contacted Memcor began pilot testing in 2010 to gain understanding of problem

20 Phase 1 Pilot Testing Summary Pilot testing of the originally installed S10V modules conducted August 2010 through June 2011 Pilot unit experienced same integrity issues as the full scale system Cause identified as abrasion of the fibers by small particles such as diatoms, which compromised the outer surface of the fibers

21 Phase 2 Pilot Testing Summary Pilot testing of the new S10N UF modules conducted August 2011 through June 2012 Pilot unit modules showed dramatic improvement in integrity TMP remained low and permeability high throughout the test period

22 Pilot Testing Results for N Module at Yuba City

23 Integrity Testing Results for N Module at Yuba City

24 New Memcor Membrane Solves Integrity Issues New membrane module N module Improvements: Increase membrane skin thickness, with minimal change to ID/OD - This should decrease the fiber damage when the surface is scratched by abrasive particles Improved potting chemistry to reduce swelling and cracking Stopped fiber preservative use to avoid the hollowing effect around the fibers

25 Memcor Conducting Extensive Testing of New Membrane N Module Testing - Side-by-side comparison data between old module and new module - Results very promising - The new module shows much lower PDT decay and higher permeability - New module testing at Yuba City and West Basin N Module submitted to NSF for NSF-61 requirements and to meet California Title 22 Alternative Filtration criteria

26 Siemens Water Recently Commercialized an Enhanced PVDF Hollow Fiber Membrane Product is available in all hollow fiber membrane applications: potable, reuse, industrial pretreatment to reverse osmosis (RO), seawater desalination pretreatment to RO, and membrane bioreactor (MBR) Over the past 12 to 15 months, Siemens has validated this product on laboratory-, pilot-, and full-scale installations

27 Advancements in Permeability and Abrasion Resistance Research shows membrane permeability of a membrane fiber directly correlates to abrasion resistance of the membrane fiber N Fiber after 1 month of harsh, accelerated abrasion testing Little visible evidence to suggest degradation

28 Improved Fiber Morphology Drives System Improvements

29 And with the Resulting Permeability Enhancement a Reduction in Pumping Requirements

30 Contracted Installations with Capacities as of February 2012 Size (mgd) Source Location 8 GWUI Northeastern US 6 Clarified Surface Water Southern US 5 Clarified Surface Water Southern US 1 Flashy Surface Water Western US 95 Seawater Source Australia 1.4 Secondary Effluent Southern US 2 Industrial Process Water Asia 4.2 Coagulated Surface Water Source UK

31 Siemens Memcor S10N Module Specification 131 mm 5.2 in 1,195 mm 47 in Parameter Module Operating Process Typical Applications Membrane Type Filtration Flow Direction Backwash Type Membrane Material Other Wetted Module Components Details Submerged Ultrafiltration General Applications Hollow Fiber Nominal Membrane Pore Size 0.04 µm Outside to Inside Nominal Membrane Area 23 m 2 / 250 ft 2 Nominal Fiber OD/ID Nominal Module Diameter (Overall) Approximate Module Mass Air Scour with Liquid Backwash PVDF (Polyvinylidene Fluoride) Polyurethane, Polyethylene, Polyamide, EPDM 1.03 mm / 0.54 mm 131 mm / 5.2 inches 7.5 kg / 16 lbs

32 Siemens Memcor S10N Module Specification cont.

33 Summary Yuba City constructed a 12 mgd expansion of their water treatment plant using Memcor submerged membranes in 2008 To address membrane integrity issues Siemens conducted two pilot tests: one with the existing S10V, and the new S10N The results of the S10N membrane testing were very encouraging, with LRV values greater than 4.0 with only minor pinning

34 Summary (cont d) Based on testing results at Yuba City and other locations, Memcor has begun production of the new modules for future projects Approval to operate granted by Redding office of CDPH - final approval for Alternative Filtration criteria is expected soon New modules installed in May 2013 and have been operating well new Flux = 36.5 gfd