Anthony Sacco Spartan Environmental Technologies, LLC & Paul Overbeck International Ozone Association

Transcription

1 Ozone Drinking Water Treatment Applications and Operational Improvements Ohio Section AWWA 18 September 2008 Anthony Sacco Spartan Environmental Technologies, LLC & Paul Overbeck International Ozone Association

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3 OZONE Providing Multiple Benefits Oxidation TOC Fe/Mn Hydrogen Sulfide Taste & Odor Color CL2-DBPs EDC Disinfection Bacteria Virus Parasites Flocculationlation Less Chemical Coagulant Lower solids Handling Lower Turbidity & Particles Longer Run time Less Backwashing Photo Courtesy of SNWA

4 Ozone destroys bacteria, viruses, cysts and parasites

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6 Bacteria Inactivation by Ozone CT = residual concentration (mg/l) x time (min) E. coli mg-min/l = CT (2-log)AWWA Streptococcus faecalis mg-min/l = CT (2-log)AWWA Legionella pneumophila mg-min/l = CT (2-log)AWWA Total Coliform 019mg-min/L 0.19 = CT (6-log) LAAFP HPC 0.19 mg-min/l = CT (3-log) LAAFP

7 Ct Values (mg x min./l) For 99.9 % Inactivation of Giardia and 99.99%Virus Data for 5 C Free Chlorine Chloramine Chlorine Dioxide Ozone ( ph 6 to 7 ) ( ph 8 to 9 ) ( ph 6 to 7 ) ( ph 6 to 7 ) Giardia Virus Taken from: Optimizing Water Treatment Plant Performance Using Composite Correction Program. prepared by Process Applications, Inc., for the U.S. EPA, Office of Drinking Water, Cincinnati, Ohio.

8 US EPA CT Values for Virus Inactivation i by Ozone Temperature C Inactivation i < log log log

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10 Drinking Water Regulatory Backdrop Longstanding Dilemma Micro DBP bial Risk Risk Government Interest Level of Chemical Disinfection

11 Disinfection By-Products Chlorine -Trihalomethanes (THM) -Haloacetic Acids (THAA 5 ) -Bromate Ozone -Bromate -Assimilable Organic Carbon (AOC)

12 How does ozone/biofiltration work? Synergy between ozone and biofiltration Results in TOC/COD/BOD reduction NOM O 3 Breaks macro molecular NOM and many SOC to biodegradable OM Organics NOM Biofilter HO break SOC TO biodegradable d bl OM Increases microbial growth in filters

13 By-Product Formation THM/HAA Pre- and Postchlorination Ozonation & Postchlorination Concentration n (ppb) TTHM HAA5 Courtesy of Gwinnett County, Georgia

14 Dramatic disinfection-by-product i d t reductions RAA MCL 80 ( u g /L) Averag e Q3-04 Q4-04 Q1-05 Q2-05 Q3-05 Q4-05 Q1-06 Q2-06 Q3-06 Qtrly TTHM Avg Running A nnual A vg MWRA

15 Summary Bromate Formation Control Chemical Addition Options Chlorine Ammonia Alkalinity Organic Matter ph Adjustment Temperature Control Lower O3 Applied Dose & Reaction Time

16 Ct B. Daw, et.al Formation Potential (BrO3 µg/l)

17 Microflocculation Improved Floc/Clarification & Filtration TOC Reduction Dosage Influenced by ph, TOC Extends Filter Runs Reduces Solid Handling

18 Microflocculation

19 Organic Color Reduction

20 Taste & Odor Oxidation Ozone Alone Advanced Oxidation Processes Algal Sources methyl isoborneal (MIB) Geosmin Other Organic Matter

21 Use of Ozone for Taste and Odor Control has been Successful: Tastes great, less chlorine May 14, 1994 Ozone treatment makes water safer, taste better July 25, 1995

22 Water Treatment Performance Emerging Contaminants EDC Removal <50% 50-59% 60-69% 70-79% 80-89% 90-99% Monylphenol Atrazine Meprobromate Acenaphtylene Trimethoprim Diazepam BHC Naphtalene Iopromide Phenolythrene Acetaminophen Oxybenzone Musk Ketone Heptachlor Aldrine Anthracene Caffeine Progesterone Dieldrin DDE Galaxolide Erythromyein-H 2 O Ethynylestradin Endrin Metolachlorine Sulfamethozazone Testroterone Benzo (a) Fluoxetine Andeostenedione pyrene Chrysene Pentoxifylline Naproxen Methoxychlor Pilantin Ibuprofen Carbcamazepine DEET Fluorene Pyrene Fluoraythene Diclofenae Triclosan Gernfibrozil Octylphenol Courtesy of SNWA

23 Components of an Ozone System Feed-Gas Supply Options (Select 1) Ozone Generation Moisture Removal System Air Power Supply Unit Ambient Air Supply CRYO O 2 System PSA O 2 System VPSA O 2 System O 2 O 2 O 2 Flow Meter O 3 % wt Purchased LOX O 2 Ozone Generator Ozone Contacting Options (Select 1) Flow Control Valve M Flow Meter Bubble Diffuser Ozone Contactor Injection Ozone Contactor t Off-Gas O 3 Destruct Blower

24 Important Advancements in Ozone System Design and Operation Lowered capital and O&M cost by switching to oxygen feed-gas (LOX and VPSA) and improvements in ozone generator design Developed/implemented p robust process monitoring and control Improved fine bubble diffusion & side stream Improved fine bubble diffusion & side stream dissolution

25 From Air to Oxygen: Pre-1987, 1987 to 1993 and Post 1993 Sp pecific Ene ergy, kwh/l b kwh/kg Low Frequency Air-fed 17.6 Medium Frequency Air-fed Medium Frequency 6.6 Medium Frequency High Efficiency Oxygen-fed Oxygen-fed Ozone Concentration, %wt

26 Ozone Equipment is Simplified Earlier air-fed ozone systems Desiccant Air Compressor Refrigerant Dryer Dryer Ozone Generator Less equipment = Lower maintenance, capital cost, and operating cost Liquid Oxygen Storage & Ambient Vaporizers Ozone Generator Current oxygen-fed ozone systems

27 Ozone Residual Monitoring has Improved Indigo Trisulfonate Standard Method ozone residual test Trustworthy on-line residual analyzers and robust sampling systems Display Range: PPB, PPM Accuracy: ± 0.02 PPM or 0.5% of F.S. Repeatability: ± 0.01 PPM or 0.3% of F.S. Linearity: 0.1% of F.S. Zero Drift: < PPM per month

28 Las Vegas, AMS Water Treatment Plant Water flow varies from 150 to 550 MGD twice per day Dose target = 1.1 mg/l Range = 1.0 to 1.2 Gas flow is constant Ozone production range is 1500 to 5500 lb/day 7 days of hourly data

29 Controlling Disinfection is the Performance GOAL (e.g., Giardia) MWD Jensen August % of time PR>2 (1-log) 1% of time PR>4 (2-log) Average PR = 3 or 1.5-logs

30 Ozone Dissolution Options Bubble Diffuser Side Stream ---- L Water Flow Ozone G High Efficiency Venturi Injectors Historically, the most common ozone contacting option For many reasons, the side stream option is becoming more popular today

31 Fine Bubble Diffuser Material Improvements Alternative expanded- Teflon gaskets that are gaining popularity for use in oxygen-fed ozone applications Hypalon diffuser gaskets after 2-yr service in a high-ozoneconcentration (8%wt) oxygen-fed ozone application One-piece design is formed of a gas permeable porous alumina diffuser ceramic bonded at high temperature yielding a corrosion resistant product. Stainless steel components, polymer gaskets and cements of any kind have been eliminated.

32 Option 1 - Designed to maximize ozone transfer within the side stream flow P From Ozone Generators FM Gas flow control valve M Fail-close Shut-off Valve M Liquid Trap High Pressure Switch P P s Pressure Control P M Heater Ozone Destruct To Atmosphere P FM P Check Valve P P Pressure Control (Optional) Sidestream Pump Venturi Injector Degas Vessel P Water Flow Mixingenhancement nozzles

33 Option 2 - Designed to utilize ozone contactor for ozone transfer assistance P From Ozone Generators FM Gas flow control valve M Fail-close Shut-off Valve Liquid M Trap High Pressure Switch P P s G M P Heater Destruct To Atmosphere P FM P Check Valve P Sidestream Pump L Venturi Injector Mixing-enhancement nozzles Water Flow

34 International Ozone Association Joint IOA & IUVA Conference May 2009 Boston, MA Anthony Sacco Spartan Environmental Technologies, LLC & Paul Overbeck International Ozone Association