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Willow Valley Water Company Alternative Oxidant & Corrosion Control Studies, Strategies & Solutions - May 4, 2012

WVWC - Alt Oxidant & CC - AZ Presentation May 2012

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Page 1: WVWC - Alt Oxidant & CC - AZ Presentation May 2012

Willow Valley Water CompanyAlternative Oxidant & Corrosion Control – Studies, Strategies & Solutions - May 4, 2012

Page 2: WVWC - Alt Oxidant & CC - AZ Presentation May 2012

Willow Valley Water CompanyAlternative Oxidant & Corrosion Control – Studies , Strategies & Solutions

Joel Wade – Global Water Resources

Page 3: WVWC - Alt Oxidant & CC - AZ Presentation May 2012

Presentation Overview

Facility Information/Project BackgroundPrimary TechnologyBench Scale TestingFull Scale Pilot TestFull Scale ImprovementsResults - Capital / O&M CostsConclusions & Considerations

Page 4: WVWC - Alt Oxidant & CC - AZ Presentation May 2012

Willow Valley Water Company

Page 5: WVWC - Alt Oxidant & CC - AZ Presentation May 2012

Willow Valley Water CompanyChallenges with Newly Acquired Water System

Willow Valley Water CompanyUnder 2,000 customers5 - Active Groundwater WellsRated Capacity: 2-Sites 890 Kgal/dayPurchased by Global Water - 2006SWDA - Groundwater Rule – Disinfection Required.Tough Water!

Iron – 1.2 mg/lManganese – 1.5 mg/lTotal Organic Carbon - 3.2 mg/l

Page 6: WVWC - Alt Oxidant & CC - AZ Presentation May 2012

Good Oxidants – Doing Bad Things!

Page 7: WVWC - Alt Oxidant & CC - AZ Presentation May 2012

½” Iron Deposits

3-1/2”Manganese Deposits

2” Free Flow Area of Pipe

Page 8: WVWC - Alt Oxidant & CC - AZ Presentation May 2012

Fe & Mn RemovalCimarron / Unit 17

Built with limited controls and flexibilityExperiencing process stability issues using sodium hypochlorite as the oxidant at design capacityLimited contact time further stresses water clarityCapacity limited by organic and solids loading not hydraulics

Oxidant: Sodium hypochloriteOxidant Contact : 6 min (Unit 17), 0 min (Cimarron)Filtration: 2 Parallel Units -Manganese Dioxide Coated MediaDisinfection: Sodium Hypochlorite

Disinfection / Storage / Pressure Boosting

FiltrationOxidant /Contact Tank

Groundwater Well

Page 9: WVWC - Alt Oxidant & CC - AZ Presentation May 2012

Pureflow Filtration Technology

Page 10: WVWC - Alt Oxidant & CC - AZ Presentation May 2012

CORROISION CONTROL STUDY16 - Sample Points26 - Constituents 12 - Calculated Indices 2 – Chemistry Models

Material SurveyWater Age ModelPipe Velocity ContoursTrend Map – Cu+ hits

Page 11: WVWC - Alt Oxidant & CC - AZ Presentation May 2012

Copper 2.5 mg/l

Copper1.9 mg/l

Copper 2.1 mg/l

Page 12: WVWC - Alt Oxidant & CC - AZ Presentation May 2012

Water Age of High Copper Areas Residential Address Water Age (Hrs)System Address #1 - 1568 E. Puma Rd. 60System Address #2 - 1648 Valley Pkwy 70System Address #3 - 1770 Emily Dr. 58System Address #1 - 8170 Aspen 20System Address #2 - 1093 Pine 20System Address #3 - 7793 Green Valley 20System Address #4 - 467 Kingsley 30System Address #5 - 8663 ASH 35System Address #6 - 1430 E. Commercial St. 50

Page 13: WVWC - Alt Oxidant & CC - AZ Presentation May 2012

Typical Corrosion Sampling Suite

pH/ORPConductivity / Total Dissolved SolidsAlkalinity – Total / PhenolphthaleinTotal Hardness Lead/CopperSulfate/ SRBsDissolved Oxygen / Carbon Dioxide

Chlorine/Chloride-Nitrate/ Sulfate Iron / IRBs Total Organic Carbon (TOC) .Dissolved Inorganic Carbon (DIC)Calcium Bicarbonate/Magnesium Bicarbonate

Page 14: WVWC - Alt Oxidant & CC - AZ Presentation May 2012

Water Quality AveragesParameter Max Min Average

ORP (mV) 553 121 269Temp (deg C) 25.3 22.1 24.3

pH (units) 8.13 7.4 7.73Cond (uS/cm) 2500 1388 2004

TDS (ppm) 1770 973 1414 CO2 (mg/l) 25 10 17DO (mg/l) 10.8 3.7 6.2TOC (mg/l) 2.7 2 2.4DIC (mg/l) 75 53 65.4

T-Alk 320 168 255Ca- Hard 630 148 408Mg-Hard 246 62 152Sulfate 710 378 570

Phosphate 2.8 0.84 1.84Chloride 250 130 192

Manganese 1.24 0.035 0.306Iron 1.4 0.012 0.295Lead 0.6 0.012 0.088

Copper 2.57 0.014 0.595

Page 15: WVWC - Alt Oxidant & CC - AZ Presentation May 2012

RTW Water Chemistry Model Input

Page 16: WVWC - Alt Oxidant & CC - AZ Presentation May 2012

RTW Model Output Graph

Page 17: WVWC - Alt Oxidant & CC - AZ Presentation May 2012

Trussell Tech. Water Chemistry Model

Ionic StrengthDissolved Inorganic CarbonCaCO3 – Precipitation Potential

Page 18: WVWC - Alt Oxidant & CC - AZ Presentation May 2012

Water Quality IndexingWQ Index Max Min Average Indicator Range

pH (Units) 8.13 7.4 7.73

pHs (Units) 7.28 6.71 6.89

LSI (units) 1.38 0.45 0.84 -1.0 to +2.0

CCPP Index 78.92 21.4 50.42 4-10 mg/l

Ryznars Index 6.76 5.48 6.03 5 to 10

Aggressive Index 12.97 12.24 12.71 10 - 12 units

Ionic Strength (mol/l)

0.0416 0.0246 0.0344 0 - 0.05 mol/L

Larson Sklod Index

4.64 2.21 3.01 0.8 – 1.2

Baylis curve Scale Scale Scale Incrustation / corrosion

DIC (Calculated) (mg/l)

81.1 41 63.2 10 – 30 mg/l as C

Alk/Chloride + Sulfate Ratio

0.33 0.33 0.29 Greater than 5.0

Page 19: WVWC - Alt Oxidant & CC - AZ Presentation May 2012

Baylis Curve Zone A – No Corrosion

Page 20: WVWC - Alt Oxidant & CC - AZ Presentation May 2012

Non-Corrosive Water?? Not So Fast,

Average pH 7.7 – Check!Average Alkalinity 255 – Good!Average LSI - 0.84, Slightly Positive – Stable!Ryznars Index – 6.03 Mid range of stability – Check!Baylis Curve – Non-Corrosive – Deposition ZoneLarson Skold – 3.01 Not So Much!Alkalinity Chloride + Sulfate Ratio 0.29 – Way Out of Range!

Page 21: WVWC - Alt Oxidant & CC - AZ Presentation May 2012

Corrosion Control SummarySlow oxidation reactions due to high levels of TOC in the raw water cause overuse of oxidants related to Iron and Manganese removal. Increased DIC concentrations related to the iron and manganese filtration process, may be the leading cause of increased copper solvency of the contact water. High chloride and sulfate concentrations stripping away protective films, required to offset high oxidation potential & electro conductivity.

Page 22: WVWC - Alt Oxidant & CC - AZ Presentation May 2012

Elevated DIC – What to do?

Page 23: WVWC - Alt Oxidant & CC - AZ Presentation May 2012

How to fix itSimple Ratio - ALK/ (Cl- + SO4)

Increase Alk or Reduce Cl-, SO4-

DIC limits Alk – Beware of CSI!Use Polyphosphate as protective coatingEliminate NaOCl- – Reduce Chloride

Hydrogen Peroxide - Not effective with TOCOzone – Material compatibility issues, Can reform MnO4

Sodium Permanganate – Slow acting, Can reform MnO4

Chlorine Dioxide – Fast Acting, No THMs Ok, Lets try it!

Page 24: WVWC - Alt Oxidant & CC - AZ Presentation May 2012

Why Not NaOCl- ?

Page 25: WVWC - Alt Oxidant & CC - AZ Presentation May 2012

Chlorine Dioxide Advantages

Detention Time – ClO2 reactions are instantaneous, reducing contact time requirements and is 10 times more soluble in water than chlorine.Increased effectiveness with increasing pH (opposite of chlorine).More effective than chlorine for virus inactivation.Powerful enough to oxidize Iron Manganese in the presence of high TOC.Can inactivate THM precursors without forming THM or HAA5s.Improves taste and odor from organics, algae and sulfides.CLO2 provides a chlorine residual, while other oxidants may not.CT requirements are initiated at point of use, reducing the amount of chlorine required to meet CTCl2 gas can reduce disinfection costs by 2/3

DisadvantagesClO2 forms chlorite which is regulated constituent, limiting the concentration that can be fed.On-site generation process control can vary efficiency of product.Training, sampling and lab efforts are higher than that of Chlorine.On-site generation equipment capital costs are higher than NaOCl-

Cost per lb of oxidant is 4.3 times higher than the cost of NaOCl - , but dosage is 2.7 times less than NaOCl- .ClO2 decomposes in sunlight.Safety concern of ClO2 is greater than that of NaOCl- .When spilled or agitated, liquid ClO2 can produce chlorine gas.

Page 26: WVWC - Alt Oxidant & CC - AZ Presentation May 2012

Bench ScaleTesting Dissolved Mn vs. Oxidant Dose: Unit -17 Well

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.00.00

0.20

0.40

0.60

0.80

1.00

1.20

1.40

Oxidation of Mn2+ in raw water by Cl2 alone ,ClO2 alone and MnO4 + ClO2. For combined process, ClO2 dose was 1.5 mg/L. Initial Mn2+ = 1.35 mg/L. Temp. = 10 C, pH = 7.4 - 7.5. TOC = 3.56 mg/L.

Cl2 AloneCl2 + ClO2 (ClO2 dose = 1.5 mg/L)ClO2 AloneMnO4- + ClO2 (ClO2 dose = 1.5 mg/L)

Unit 17 - Oxidant Dose (mg/L)

Diss

olve

d M

n (m

g/L)

Page 27: WVWC - Alt Oxidant & CC - AZ Presentation May 2012

Bench Scale Testing Dissolved Mn vs. Oxidant Dose : Cimarron Well

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 50.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0.80

0.90

1.00

Oxidation of Mn2+ in Cimmaron raw water by Cl2 alone, Cl2 + ClO2 and ClO2 alone and Detention time = 5 min. Initial Mn2+ = 0.626 mg/L. Temp. = 10 C, pH = 7.3 - 7.4. TOC = 2.45 mg/L.

ClO2 onlyCl2 AloneCl2 + ClO2 (ClO2 dose = 1.0 mg/L)

Cimarron Oxidant Dose (mg/L)

Diss

olve

d M

n (m

g/L)

Page 28: WVWC - Alt Oxidant & CC - AZ Presentation May 2012

Full Scale Pilot Test Liquid Chlorine Dioxide – Pentasodium Tripolyphosphate

Page 29: WVWC - Alt Oxidant & CC - AZ Presentation May 2012

Pilot TestingPilot Unit Overview

CDG Solution 3000 – Liquid Chlorine Dioxide 330-gallon toteVariable Speed DrivePeristaltic Pump SkidWestfall Static Mixers50 gallon NaMnO4 & PumpInjection QuillsRubbermaid Storage UnitNa4P2O7 – Mixing & Chemical Feed StationConcrete Pad

Page 30: WVWC - Alt Oxidant & CC - AZ Presentation May 2012

Pilot Test Equipment

Page 31: WVWC - Alt Oxidant & CC - AZ Presentation May 2012

Pilot Testing Summary

Cimarron Full-Scale Pilot Results

Constituent Before AfterFe Removal (%) 84.3 99.3

Mn Removal (%) 55.5 88.0TTHM (ug/l) 0.100 0.059TOC (mg/l) 2.7 2.4

Max Copper Sampled (mg/l)

1.30 0.35

Unit 17 Full-Scale Pilot ResultsConstituent Before After

Fe Removal (%) 91.0 98.1Mn Removal (%) 70.4 87.1

TTHM (ug/l) 0.120 0.056TOC (mg/l) 3.4 3.0

Max Copper Sampled (mg/l)

2.77 0.56

Page 32: WVWC - Alt Oxidant & CC - AZ Presentation May 2012

Storage Tank

To D

istrib

utio

n Sy

stem

Well No. 1

Well No. 2

Raw Water

Treatment System Bypass

Iron & Manganese Treatment

Unit 17Distribution Pump Station

Onsite Chlorine Dioxide Oxidant Generator/Feed

System

Tetrasodium Pyrophosphate

Sodium Permanganate

Feed

Chlorine Gas Feed System

Full Scale Improvements

Page 33: WVWC - Alt Oxidant & CC - AZ Presentation May 2012

CDG Gas:Solid™ Process

Cl2 + 2NaClO2 2ClO2 + NaCl

Chlorine Gas Solid Sodium ChloriteSAF-T-CHLOR™

Chlorine Dioxide Gas Solid Sodium Chloride

½ lb gas chlorine passing through Sodium chlorite makes 1 pound of Chlorine Dioxide

Page 34: WVWC - Alt Oxidant & CC - AZ Presentation May 2012
Page 35: WVWC - Alt Oxidant & CC - AZ Presentation May 2012
Page 36: WVWC - Alt Oxidant & CC - AZ Presentation May 2012

Chemical Injection Unit 17

Page 37: WVWC - Alt Oxidant & CC - AZ Presentation May 2012

Static MixerUnit 17

Page 38: WVWC - Alt Oxidant & CC - AZ Presentation May 2012

Lab Requirements

Daily Chlorine Dioxide at EPDS – HACH Field KitDaily Chlorite at the EPDS – HACH AutoCat 900Monthly Chlorite – Third Party – Three Samples

Page 39: WVWC - Alt Oxidant & CC - AZ Presentation May 2012

Oxidant Dosage OptimizationParker THM Analyzer

Page 40: WVWC - Alt Oxidant & CC - AZ Presentation May 2012

Cimarron Site

Page 41: WVWC - Alt Oxidant & CC - AZ Presentation May 2012

Cimarron Site

Page 42: WVWC - Alt Oxidant & CC - AZ Presentation May 2012

Twin Feed – Chlorine Gas

Page 43: WVWC - Alt Oxidant & CC - AZ Presentation May 2012

Cimarron CLO2 Generator

Page 44: WVWC - Alt Oxidant & CC - AZ Presentation May 2012

Unit 17Full Scale Improvements

Page 45: WVWC - Alt Oxidant & CC - AZ Presentation May 2012

NaMnO4 & Na4P2O7 Feed Station

Page 46: WVWC - Alt Oxidant & CC - AZ Presentation May 2012

Great! But What Does It Cost?

Capital Costs – $172,000 ($0.38 per gallon)Chlorine Gas System - $37,800Chlorine Dioxide Generator - $67,300CC Pad & Tuff Shed Structure - $4,500Sodium Permanganate feed station - $750Tetrasodium Pyrophosphate Feed Station - $1,500Backflow, piping and static mixers - $15,000Electrical Improvements - $5,000Settling Tanks and Ancillary Equipment – $10,000In-House Labor - $30,000 - Constructed in 8-Weeks!

Page 47: WVWC - Alt Oxidant & CC - AZ Presentation May 2012

Production Costs ComparisonSite

LocationProduction

(Kgal)Oxidant&

Disinfection ($)

Power ($)

Prod Cost ($/kgal)

Unit 17 (2010) 104,209 11,823 26,152.38 $0.36

Cimarron (2010) 12,306 1,395.02 5,189.71 $0.54

SiteLocation

Production (Kgal)

Oxidant ($)

Disinfection ($)

Corrosion Inhibitor

($)

Power ($)

Prod Cost ($/kgal)

% CostIncrease

Unit-17 (3/2012)

5,976 1,848.62 305.31 87.41 1948.81 $0.70 94.4

Cimarron (3/2012)

872 258.67 42.64 11.78 576.03 $1.07 98.1

Page 48: WVWC - Alt Oxidant & CC - AZ Presentation May 2012

Yearly Production CostCimarron / Unit 17

Cimarron Jan Feb March April May June July Aug Sept Oct Nov Dec Total

Prod (Kgal) 741 671 807 743 898 944 935 1,229 1,121 1,112 801 724 5,792

Prod($) 2010

$400 $362 $436 $401 $485 $510 $505 $664 $605 $600 $433 $391 $5,792

Prod($) 2012

$793 $718 $863 $795 $961 $1,010 $1,000 $1,315 $1,199 $1,190 $857 $775 $11,477

Change($)

$393 $356 $428 $394 $476 $500 $496 $651 $594 $589 $425 $384 $5,685

Unit 17 Jan Feb March April May June July Aug Sept Oct Nov Dec Total

Prod (Kgal) 5,931 5,857 7,039 7,519 9,303 8,303 9,467 9,975 7,514 6,543 8,728 4,875 91,054

Prod($) 2010

$2,135 $2,109 $2,534 $2,707 $3,349 $2,989 $3,408 $3,591 $2,705 $2,355 $3,142 $1,755 $32,779

Prod($) 2012

$4,152 $4,100 $4,927 $5,263 $6,512 $5,812 $6,627 $6,983 $5,260 $4,580 $6,100 $3,413 $63,738

Change($) $2,017 $1,991 $2,393 $2,556 $3,163 $2,823 $3,129 $3,392 $2,555 $2,225 $2,968 $1,658 $30,958

Page 49: WVWC - Alt Oxidant & CC - AZ Presentation May 2012

ConclusionsFE & Mn Removal w/o Copper CorrosionAlternative Oxidants can Improve Fe & Mn Removal w/o TTHMCheck CPI Before considering Alkalinity AugmentationClO2 + MnO4 – Most effective in combinationCLO2 Can Be User Friendly

Page 50: WVWC - Alt Oxidant & CC - AZ Presentation May 2012

Acknowledgements

St. Mary's WTP - Flagstaff Az.Valencia Water Company Utilities Staff.Pureflow Filtration/Reaco Associates, LLC.Chemical Feeding Technologies, Inc.Parker Hannifin CorpCDG Environmental Steve Osborn, James Taylor – Global WaterWillow Valley Operations Staff

Page 51: WVWC - Alt Oxidant & CC - AZ Presentation May 2012

And Isn't This What It’s Really About??

Any Questions ??