Simultaneous Solutions Simultaneous Solutions for Aesthetics and for Aesthetics and Other Water Quality Other Water Quality ProblemsProblems

Simultaneous Solutions Simultaneous Solutions for Aesthetics and for Aesthetics and Other Water Quality Other Water Quality ProblemsProblems

Stephen Booth, PhD

Craig Thompson, PE

Water Quality IssuesWater Quality Issues

▼ Aesthetics Taste & Odor Color Particulate matter

▼ Other Issues Disinfection DBPs and Precursors Treatability

USEPA SMCLs - AestheticsUSEPA SMCLs - Aesthetics

Contaminant Effects SMCL in ppm

Aluminum Colored water 0.05-0.2

Chloride Salty taste 250

Color Visible tint 15 color units

Copper Metallic taste, staining 1.0

Corrosivity Metallic taste, staining Noncorrosive

Foaming agents Frothy, cloudy, bittertaste

0.5

Iron Rusty, metallic taste,staining

0.3

USEPA SMCLs – AestheticsUSEPA SMCLs – Aesthetics (Cont’d)(Cont’d)

Contaminant Effects SMCL in ppm

Manganese Bitter-metallic taste,color, staining

0.05

Odor Odor 3 TON

pH Low pH – bitter,metallic tasteHigh pH – slipperyfeel, soda taste

> 6.5

< 8.5Sulfate Salty taste 250

Total DissolvedSolids (TDS)

Salty taste, staining 500

Zinc Metallic taste 5

Groundwater AestheticsGroundwater Aesthetics

▼ Iron-reducing bacteria and soluble iron▼ Sulfur-reducing bacteria and sulfides▼ High mineral content▼ Salt water intrusion▼ Contamination

Surface Water IssuesSurface Water Issues

▼ Planktonic and benthic algae▼ Proliferation of algae in reservoirs▼ Agricultural runoff▼ Industrial discharges▼ Wastewater plant discharges

Surface Water Odor QualitiesSurface Water Odor Qualities

▼ Earthy/Musty▼ Grassy/Green

Vegetation▼ Decaying/Marshy▼ Fishy▼ Septic▼ Medical/Chemical

▼ MTBE (chemical)▼ Woody/Hay▼ Soapy

After Treatment…After Treatment…

▼ Distribution system issues▼ Plumbing and storage

Geosmin Geosmin (t-1,10-dimethyl-t,9-decalol)(t-1,10-dimethyl-t,9-decalol)

▼ Geo (earth) + osme = odor▼ Customer complaints common > 10 ng/L▼ Odor threshold at 45°C ~5 ng/L

2-MIB 2-MIB (2-Methylisoborneol)(2-Methylisoborneol)

▼ Odor descriptors: musty, peaty, earthy, damp soil▼ Sensitivity highly variable

Treatment TechniquesTreatment Techniques

▼ Established:▼ Oxidation▼ Adsorption

▼ Emerging:▼ Advanced Oxidation▼ Biodegradation▼ Alternate

Adsorbents

Complex design and operationComplex design and operationSignificant costsSignificant costs

Evaluating AlternativesEvaluating Alternatives

▼ Oxidation / Advanced Oxidation Ozone Chlorine dioxide Potassium permanganate UV + Peroxide

▼ Adsorption GAC PAC

Taste versus Safety RatingsTaste versus Safety Ratings

0123456789

10

Dirty/Earthy

Chlorine

Salty

Data from MWDSC/USBR Salinity Data from MWDSC/USBR Salinity Management Study, June 1999.Management Study, June 1999.Sample of five Southern California Sample of five Southern California communities. Initial sample = 1503communities. Initial sample = 1503

10 = Perfectly Safe10 = Perfectly Safe

0 = Very unsafe0 = Very unsafe

Lake Bard Water Filtration PlantLake Bard Water Filtration Plant

▼ Calleguas Municipal Water District▼ Source water is Lake Bard▼ Seasonal algae problems results in T&O▼ Ozone process

Oxidizes T&O Improves micro-flocculation High downstream filtration rates (9 gpm/ft2)

Oxygenation System Schematic Oxygenation System Schematic

Tower and Eduction SystemTower and Eduction System

Jamieson Canyon Water Jamieson Canyon Water Treatment PlantTreatment Plant

▼ City of Napa, CA▼ Current plant expansion: 12 to 24 mgd▼ North Bay Aqueduct Water Quality

Episodes of elevated TOC and turbidity Terminal Reservoir subject to algae and T&O

Open (sunlight) Nutrient input from bird population

Raw Water QualityRaw Water Quality

Parameter Average Range

Raw water TOC (mg/L)

5.7 1.1 - 16

Filtered water TOC (mg/L)

3.6 0.5 - 10

Monthly average peak raw water turbidity (NTU)

40 20 – 70

Ozone System Design CriteriaOzone System Design Criteria

Item Value

Number of Cells 5

HRT at 24 mgd 5 min

Ozone Dose Avg. (Max.) 1.5 (3.0) mg/L

Ozone Usage Avg. (Max.) 250 (400) lb/day

Source Gas LOX

Jamieson Canyon WTP Jamieson Canyon WTP (Cont’d)(Cont’d)

▼ Pre-Ozone for simultaneous benefits: T&O treatment Pre-oxidize without forming THMs and HAAs Oxidation of organics and color Lower coagulant dosage

Jamieson Canyon WTP Jamieson Canyon WTP (Cont’d)(Cont’d)

▼ Pre-Ozone for simultaneous benefits: Disinfection benefit Ability to use settled water pipe as intermediate

ozone contactor Removal of PPCPs

ConclusionsConclusions

▼ Taste and odor quality important to consumers▼ Expense of T&O treatment drives us to look for

multiple benefits▼ Opportunity for creativity