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San Jacinto River Authority Water Quality 2011
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San Jacinto River Authority Water Quality 2011

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Published

SJRA …

SJRA
Drinking Water Quality
August 31 & September 1, 2011

Presented By:
Mark Smith, PE, SJRA GRP Administrator
Stan Williams, PE, HDR Project Manager

Published in Education , Technology , Business
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  • 1. Drinking Water Quality August 31 & September 1, 2011 Presented By:Mark Smith, PE, SJRA GRP AdministratorStan Williams, PE, HDR Project Manager
  • 2. Agenda Water Quality – Regulations and Goals Three Steps to Treatment Process Selection Post Treatment – Quality at the Tap Selected Treatment Processes Next Steps Discussion – Q&A
  • 3. Perspectives on Drinking Water Quality Regulators define Drinking Water Quality by: • Numeric Standards • Treatment Techniques • Compliance with Rule & Regulations • Monitoring & Reporting For Quality Definition – First Look to the Regulations
  • 4. Evolution of the Safe Drinking Water Act 1986 Safe Drinking Water Act (Update) Cryptosporidium Outbreak in 1993 Resulted in: • New perspective on surface water treatment • Comprehensive overhaul of industry’s approach • Unprecedented plan for new regulations • Opportunities for innovation in treatment technology
  • 5. Drinking Water Quality Additional contaminants regulated Existing technologies enhanced New treatment technologies developed New Federal Regulations • ESWTR, D/DBP, D/DBP2, LTESWTR, LT2ESWTR, FBRR, and many more High Quality Water 20 years ago would not meet today’s standards
  • 6. Project Quality Standards Consider TheRegulations AND the Consumer Project Standards go beyond the regs • Alkalinity • Hardness • Aggressiveness (corrosiveness) • Odor • Taste These Constituents Affect Water Quality AT THE TAP
  • 7. Project Quality Standards Consider TheRegulations AND the Consumer Project Definition of Water Quality: • Compliance with Regulations • Aesthetics at the tap Clarity Taste & Odor Color • Healthy and Safe • Compatible with existing groundwater sources • Consistent Quality
  • 8. Existing Source WatersGroundwater Characteristics Lake Conroe Characteristics Alkalinity - High  Alkalinity - Low Hardness - Moderate  Hardness - Moderate/Low Iron & Manganese – Yes  Iron & Manganese - Yes Aggressive – Yes  Aggressive - Yes  Turbidity - Low  Organics - High  Pathogens  Taste & Odor
  • 9. Three Step Process to SelectingTreatment Processes Step 1 - Bench Scale Studies Step 2 - Pilot Plant Studies Step 3 - Finished Water Polishing
  • 10. Structured Screening Process Establishes Viability of Alternates Possible ID Primary Treatment Desktop Study Impacts Strategy Evaluate NO Mitigation YES Impact Impacts? Possible? YES NO Develop Mitigation Implement Testing & NO Impacts Manageable? Strategies Further Evaluation YES NO YES NO Will YES Secondary NO All Impacts Mitigation Work? Impacts? Addressed? YESAbandon Strategy Implement Testing & Further Evaluation
  • 11. STEP 1 - Bench Scale Studies SelectsProcesses for Further Evaluation Review Historical Water Quality Data Conduct Bench Scale Treatability Studies Screen Potential Broken Arrow Settled Turbidity Processes 7 6 Verdigris River Raw Lake Conroe Water Water Select Processes for Step Turb. = 10.6 NTU 5 Turbidity, NTU Optimum Dose 4 2 - Pilot Testing 3 2 1 0 10 20 30 40 50 60 Aluminum Chlorohydrate Dosemg/L Ferric Sulfate Dosage, (mg/l)
  • 12. STEP 2 - Pilot Studies Test Processes Under Real Life Conditions  Construct Pilot Plant Kruger Ceramic Membranes GAC  Lake Conroe Operate Pilot Plant Static Mixer  Select/Rank Criteria Pall Microza Membranes Membrane Feed Tank  Static Influent From Lake Conroe Evaluate Processes against criteria Mixer GE ZeeWeed 1000 Discharge Tank Discharge Membranes  Select Process for Full Scale Development MIEX Contactor Conventional Plate Settler Filter Filter Feed Tank BAF Ozone Feed BAF Contactor Tank Bypass Stream From From Membrane From From Cleaning From From From BAF From Plate From From BAF Feed From BAF Kruger Feed Feed Tank Conventional Neutralization Conventional BW Tank BW Tank Settlers GAC Tank Overflow Backwash Tank Overflow Overflow Feed Tank Tank Filter Backwash Overflow Overflow OverflowGravity Discharge Collector
  • 13. Pilot Plant at Project Site
  • 14. Pilot Plant at Project Site Plate Settlers
  • 15. Membrane Filters Activated Carbon Filters (GAC)Pilot Plant at Project SiteMembrane Modules & GAC
  • 16. Activated Carbon Filters (GAC)
  • 17. Process Process Description Criteria Rank CriteriaTrain 1 Clarification + Conv. Filter 1 Community ImpactTrain 1A Clarification + Conv. Filter + UV/H2O2 2 Water Quality AestheticsTrain 1B Clarification + Conv. Filter + GAC 3 Relative Capital CostTrain 2 PS + Ozone + BAF 4 O&M Requirements and CostTrain 2A PS + Ozone/H2O2 + BAF 5 System RobustnessTrain 3 PS + Polymeric Membranes Water Integration Compatibility/Blending 6Train 3A PS + Polymeric Membranes + GAC Non-Proprietary EquipmentTrain 3B PS + Polymeric Membranes + Organix 8 Safety and Environmental Site ImpactsTrain 3C MIEX + Polymeric MembranesTrain 3D MIEX + Polymeric Membranes + GAC 9 Premium Pathogen RemovalTrain 3E PS + Polymeric Membranes + UV/H2O2 10 System SimplicityTrain 4 Ceramic Membranes 11 Area Required and Site ConstraintsTrain 4A Ceramic Membranes + GAC 12 Regulatory FlexibilityTrain 4B Ceramic Membranes + UV/H2O2 13 Ease and Cost of Expansion
  • 18. Particle Size Relationships Organic macromolecules Colloids Bacteria Viruses Pollens Yeasts 100 mm 10 mm 1 mm 0.1 mm 0.01 mm 0. 1 nm Red globule hair visible to naked eye Smallest microorganisms Polio virus Sand filter UFConventional MF Ultrafiltration Filters Microfiltration Membranes
  • 19. Relative Sizes of Small Particles Pencil Dot (40 µm) Cryptosporidium Oocysts (3 - 6 µm)Giardia Cyst(5 - 15 µm) Average size opening in a standard filter (60 µm) Microfiltration (0.1 µm)
  • 20. Conventional vs. Membrane FiltrationGranular / Mixed Media Membrane Media• Irregular Pore Size Distribution • Controlled Pore Size Distribution (50 -70 micron between grains) (0.1 micron)• Probable Filtration • Absolute Filtration 20
  • 21. STEP 3 – Finished Water Polishing Water Blending Chemistry Analyses • Sample Water from Distribution System • Sample Pipes from Distribution System • Compare compatibility with proposed treatment process Defines Required Water Chemistry Adjustments Finished Water Polishing Provides Quality Water AT THE TAP
  • 22. Understanding What’s In the Pipe Leadsto Compatible Water Chemistry  Iron scales represent a reservoir of metals, particulates, and biomass.  Chemistry changes in distribution system can release built-up deposits
  • 23. Finished Water Chemistry Must beCompatible with Existing Infrastructure Pipe Samples From Conroe Existing water is slightly aggressive Minor corrosion scale No carbonate scale build-up Design water chemistry to maintain existing corrosion scale
  • 24. Treatment Techniques for Compatibility  Sodium Hydroxide: Samples From The Woodlands • Increase pH & alkalinity  Calcium Hydroxide: • Increase pH, alkalinity and calcium  Carbon Dioxide: • Lower pHAll treatment chemicals are approved by NSF for use in drinking water
  • 25. Standard Indices Provide Goals for PostTreatment The Langelier Saturation Index (LSI) Ryznar Stability Index (RSI) Calcium Carbonate Precipitation Potential (CCPP) Larson Index (LI)
  • 26. Post Treatment Provides Stable, Compatible Water to Consumers Desired Average Conditions Parameter Value Current Treated LSI >0 -0.34 0.62 RSI <7 8.27 6.97 CCPP 4 – 10 -3.99 5.48Larson Index < 0.8 0.54 0.49
  • 27. Selected Treatment Processes Membrane Post Treatment Sedimentation Filtration & Polishing A B C 1 2 3 D E CHEMICAL TREATMENT PHYSICAL TREATMENT PROCESSES PROCESSES A Permanganate – Iron & Manganese Sedimentation – Particulate and 1 Organics Removal B Calcium Hydroxide – pH and Alkalinity Membrane Filtration – Particulate C Coagulant – TOC & Sediment Removal 2 Removal D Sodium Hydroxide – pH & Alkalinity Activated Carbon – Organic 3 E Chlorine - Disinfectant contaminants removal
  • 28. Next Steps to Quality at the Tap Acquire and analyze water samples from each receiving station – Refine post treatment plans as necessary Identify treatment techniques currently used at existing utilities Develop “Baseline Operations Report” at existing systems Develop Guidelines to assist utilities to prepare for surface water
  • 29. Summary Federal & Texas Regulations dictate very high drinking water quality Project Specific Standards drive compatibility with existing groundwater Project focuses on “Quality at the Tap” Extensive testing of treatment techniques and existing conditions provides real life results – not textbook “rules of thumb”
  • 30. SURFACE WATER TREATMENT PLANT Questions / Discussion