PRESENTATION OUTLINE

Transcription

1 Unique Water Quality Challenges of the Sheyenne River: A Comparative Pilot Study of Three MF/UF Systems Qigang Chang, PhD, PE, AE2S Troy Hall, Fargo Water Utility Director Co-authors: Brian Bergantine, Scott Freeman, Bo Johnston, Mark Peterson, and Dave Buchholz Surface Water Treatment Workshop PRESENTATION OUTLINE Project Background MF/UF Pilot Study Pilot Study Setup Pilot Study Findings Key Design Parameter Evaluation Surface Water Treatment Workshop

2 INTRODUCTION TO FARGO WTP Fargo Water Treatment Plant (WTP) in operation since 1912 Current WTP completed in 1997 with a capacity of 30 million gallons per day (mgd) Lime softening treatment plant Built to meet primary drinking water regulations Utilizes additional treatment technologies to provide aesthetically pleasing water Expandable to 45 mgd Does not remove sulfates Surface Water Treatment Workshop Lake Ashtabula Fargo s Appropriation 35,880 Acre-Feet FARGO SOURCE WATER SUPPLIES Sheyenne River Fargo s Appropriation 7,000 Acre-Feet Red River Fargo s Appropriation 109,500 Acre-Feet WTP utilizes multiple water sources Recommended by Professional Organizations Redundancy for water quality variations Drought and water shortage preparedness Manage treatment operations Minimize chemical use and cost Control taste and odor events Surface Water Treatment Workshop

3 IMPACT FROM DEVILS LAKE Devils Lake water has high concentrations of TDS: Sulfate Bromide Hardness Discharges from Devils Lake elevate concentrations of these component in the Sheyenne River Surface Water Treatment Workshop Devils Lake and Sheyenne River Water Quality Devils Lake water has high concentrations of total dissolved solids (TDS). Components problematic for drinking water treatment include: Sulfate Bromide (Bromate byproduct of ozonation) Hardness Discharges from Devils Lake elevate concentrations of these component in the Sheyenne River 6 Surface Water Treatment Workshop

4 SULFATE IN DRINKING WATER - Negative impact to taste - Laxative effect on consumers EPA Secondary Standard for Sulfate = 250 mg/l North Dakota Department of Health Recommends < 250 mg/l of Sulfate in Drinking Water Sheyenne River Sulfate Expected to be 750 mg/l (sulfate concentration was 894 mg/l on April 1, 2013) Fargo current WTP CANNOT provide sulfate treatment without additional treatment technologies Surface Water Treatment Workshop Fargo WTP Facility Plan Primary Objective Address Changing Water Quality in Sheyenne River Secondary Objective Explore Opportunities to Provide Capacity For Long-Term Growth Surface Water Treatment Workshop

5 Fargo WTP Facility Plan Fargo WTP Facility Plan Completed by AE2S and B&V in 2011 Reverse Osmosis (RO) Recognized as Appropriate Technology for Sulfate Reduction Two Preferred Alternatives Polishing RO after Existing WTP Integrated Membrane (MF/UF + RO) Parallel to Existing WTP Recommended RO Pilot Study Surface Water Treatment Workshop FARGO WTP FACILITY PLAN Fargo WTP Facility Plan Completed by AE2S and B&V in 2011 Facility Plan Objective Water Quality: Address Changing Water Quality in Sheyenne River Water Quantity: Expand Capacity For Long-Term Growth Reverse Osmosis (RO) Recognized as Appropriate Technology for Sulfate Reduction Two Preferred Alternatives Polishing RO after Existing WTP Integrated Membrane (MF/UF + RO) Parallel to Existing WTP Recommended RO Pilot Study Surface Water Treatment Workshop

6 RO PILOT STUDY RO pilot study performed in 2011 & 2012 Surface Water Treatment Workshop RO Pilot Study Scenarios Polishing Scenario SOURCE WATER EXISTING WTP REVERSE OSMOSIS (Sulfate Reduction) DISTRIBUTION Concentrate Parallel Scenario SOURCE WATER EXISTING WTP DISTRIBUTION PLATE SETTLERS (Pretreatment) MEMBRANE FILTRATION REVERSE OSMOSIS (Sulfate Reduction) Residuals Residuals Concentrate Surface Water Treatment Workshop

7 RO Pilot Study Proved the Feasibility of RO Membrane Tested Individual Performance of RO Elements Evaluated Key Design Parameters Provided Fargo WTP Staff with Membrane Experience Surface Water Treatment Workshop FARGO MEMBRANE WTP OVERVIEW Fargo Membrane WTP: 15 mgd RED RIVER FROM EXISTING LIME-SOFTENING WTP T&O CONTROL (3 MGD) 30 mgd 15 mgd 45 mgd DISTRIBUTION SYSTEM PRETREATMENT (9.5 MGD) DISINFECTION MF/UF (18.2 MGD) RO (12.0 MGD) PRETREATMENT (9.5 MGD) 0.9 mgd 2.5 mgd SHEYENNE RIVER RESIDUALS TREATMENT FACILITY CONCENTRATE DISPOSAL Surface Water Treatment Workshop

8 MF/UF PILOT STUDY Objectives Evaluate various membranes treating the Sheyenne River Establish key design and operating parameters Membrane flux, recovery, backwash, maintenance wash (MW), and clean-inplace (CIP) procedures and intervals, as well as verifying turbidity removal, low rate of fiber breakage, and direct integrity test procedures Assist Fargo WTP staff in learning about membrane filtration Pretreatment Surface Water Treatment Workshop MEMBRANE TECHNOLOGY HOW DO MEMBRANES WORK? Surface Water Treatment Workshop

9 MEMBRANE TECHNOLOGY TYPES OF MEMBRANES Smallest Pore Size Microfiltration (MF) Ultrafiltration (UF) Nanofiltration (NF) Reverse Osmosis (RO) LOW PRESSURE MF & UF Removes: Turbidity Viruses Bacteria Protozoa Organics Removal Partial Removal HIGH PRESSURE NF & RO Removes: Turbidity Viruses Bacteria Protozoa Organics Inorganics Surface Water Treatment Workshop MEMBRANE TECHNOLOGY IMPLEMENTATION CUMULATIVE CAPACITY OF US MUNICIPAL DESALINATION PLANT Mike Mickley, U.S. municipal desalination plant statistics and concentrate management practices and issue, 2012 Surface Water Treatment Workshop

10 MF/UF MEMBRANE CHARACTERISTICS Module Model Number ZeeWeed 1000 UNA-620A L20N Type of Membrane Submerged Encased Material of membrane fiber Surface area per each membrane module, ft 2 (m 2 ) Nominal pore size, (µm) PVDF 550 (51) 538 (50) 375 (35) Surface Water Treatment Workshop PILOT TESTING PROGRAM SCENARIOS Sheyenne River 1. Temperature swings widely 2. High TOC 3. High alkalinity 4. High sulfate 5. Water quality changing rapidly Degrees Celsius /1/2005 7/1/2005 1/1/2006 7/1/2006 1/1/2007 7/1/2007 1/1/2008 7/1/2008 1/1/2009 7/1/2009 1/1/2010 7/1/2010 Date 20 Surface Water Treatment Workshop

11 RESULTS AND DISCUSSION Water Quality Sheyenne River 1. Temperature swings widely 2. High TOC 3. High alkalinity 4. High sulfate 5. Water quality changing rapidly Surface Water Treatment Workshop RESULTS AND DISCUSSION Water Quality Temperature swings widely 1. High TOC 2. High alkalinity 3. High sulfate 4. Water quality changing rapidly SHEYENNE RIVER RAW WATER SETTLED WATER ph Temperature ( C) TOC (mg/l) Turbidity (NTU) Typical: <3 Maximum: <9 Surface Water Treatment Workshop

12 SHEYENNE RIVER WATER TEMPERATURE Degrees Celsius /1/2005 7/1/2005 1/1/2006 7/1/2006 1/1/2007 7/1/2007 1/1/2008 7/1/2008 1/1/2009 7/1/2009 1/1/2010 7/1/2010 Date Surface Water Treatment Workshop TRANSMEMBRANE PRESSURE Membrane A Surface Water Treatment Workshop

13 TRANSMEMBRANE PRESSURE Membrane B Surface Water Treatment Workshop TRANSMEMBRANE PRESSURE Membrane B P Rm Pore size Surface Water Treatment Workshop

14 TRANASMEMBRANE PRESSURE Membrane C Surface Water Treatment Workshop TEMPERATURE CORRECTED PERMEABILITY Surface Water Treatment Workshop

15 TEMPERATURE CORRECTED PERMEABILITY Surface Water Treatment Workshop MEMBRANE CLEAN-IN-PLACE Sodium Hypchlorite: mg/l Citric i Acid: 1-2% (ph 2) Temperature: degree F Surface Water Treatment Workshop

16 CIP EFFECTIVENESS Surface Water Treatment Workshop KEY DESIGN PARAMETER EVALUATION Design Flux? Surface Water Treatment Workshop

17 KEY DESIGN PARAMETER EVALUATION Design Flux? Factors: Design Capacity Membrane Life Time Allowable Annual Permeability Loss Lowest Water Temperature Max Allowable TMP Surface Water Treatment Workshop DESIGN FLUX EVALUATION Permeability C : Flux: A: n: TMP m : T: Minimum Membrane Permeability at 20 C (gfd/psi) Design Flux (gfd) Annual Flux Loss (percent) Membrane Life Time (year) Maximum Operation Transmembrane Pressure (psi) Lowest Water Temperature ( C) Surface Water Treatment Workshop

18 Example Surface Water Treatment Workshop Example Flux: 35 gfd A= 0.05 TMP m = 21.7 psi T=0.5 C n = 10 (year) Surface Water Treatment Workshop

19 Example Design Flux 34 gfd: 4.93 gfd/psi Design Flux 30 gfd: 434gfd/psi 4.34 Surface Water Treatment Workshop PROJECT STATUS FACILITY PLAN RO PILOT STUDY PRELIMINARY DESIGN AND MF/UF PROCUREMENT FINAL DESIGN BIDDING CONSTRUCTION WHERE WE ARE Surface Water Treatment Workshop

20 FARGO WTP SITE Surface Water Treatment Workshop FARGO MEMBRANE WTP SITE 5 th Street South Fargo Membrane WTP 13 th Avenue South Existing WTP N Surface Water Treatment Workshop

21 FARGO MEMBRANE WTP RENDERING Surface Water Treatment Workshop QUESTIONS? Qigang Chang, PhD PE Project Engineer AE2S 3101 Frontage Road South Moorhead, MN Voice: Fax: Troy Hall Fargo Water Utility Director Fargo Water Treatment Plant Ave. S. Fargo, ND Voice: Fax: Thank You! Surface Water Treatment Workshop