Slide 1

Delta Water Quality: Delta Water Quality: Implications for Utility Compliance Implications for Utility Compliance with the Safe Drinking Water Act with the Safe Drinking Water Act

Edward G. Means IIIEdward G. Means IIISr. Vice PresidentSr. Vice President

McGuire Environmental Consultants, Inc.McGuire Environmental Consultants, Inc.

(For Contra Costa Water District)(For Contra Costa Water District)

Slide 2

Delta Source Water QualityDelta Source Water Quality

1.1. Disinfection Byproducts (DBPs) are a greater public Disinfection Byproducts (DBPs) are a greater public

health issue than in 1991. Ahealth issue than in 1991. Additional DBPs likely to be dditional DBPs likely to be

regulated in future and DBP regulations will become more regulated in future and DBP regulations will become more

stringent.stringent.

2.2. Will be more difficult and expensive to comply with Will be more difficult and expensive to comply with

drinking water regulations. drinking water regulations.

3.3. There is an even greater need for improved source water There is an even greater need for improved source water

in the Delta – Need a multi-barrier approach, consistent in the Delta – Need a multi-barrier approach, consistent

with CALFED drinking water goalwith CALFED drinking water goal. .

Primary Findings . . .Primary Findings . . .

Slide 3

Delta

WaterTreatment Plant

Distribution system

Treated WaterReservoir

Source Water Quality Affects Drinking Source Water Quality Affects Drinking Water Quality and Public HealthWater Quality and Public Health

Bromide from seawater intrusion &TOC from Ag/natural sources

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Utilities Must DisinfectUtilities Must Disinfect Water To Water To Protect Public HealthProtect Public Health

Typical Typical WaterWater

TreatmentTreatment SystemSystem

Chemical Addition

Raw Water

Coagulation/Flocculation

Sedimentation

Filtration

Disinfection

Advanced Treatment (Ozone, Membranes, UV,GAC, Chlorine Dioxide)

Treated Water

Secondary Disinfection for Residuals

Slide 5

How Disinfection By-products Are How Disinfection By-products Are FormedFormed

PrecursorsPrecursors

BromideBromide

Organic CarbonOrganic Carbon

DisinfectantsDisinfectants

OzoneOzone

Chlorine Chlorine

ChloraminesChloramines

Chlorine DioxideChlorine Dioxide

ByproductsByproducts

BromateBromate

TrihalomethanesTrihalomethanes

Haloacetic AcidsHaloacetic Acids

Other DBPsOther DBPs

++ ==

DBP precursors react with disinfectants to produce by-DBP precursors react with disinfectants to produce by-products of human health concern . . .products of human health concern . . .

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Urban Agencies Must Meet Urban Agencies Must Meet Drinking Water RegulationsDrinking Water Regulations

• USEPA regulates drinking water under the USEPA regulates drinking water under the federal Safe Drinking Water Act.federal Safe Drinking Water Act.

• Source water quality is regulated under the Source water quality is regulated under the federal Clean Water Act.federal Clean Water Act.

• Cal. DoHS has primacy (i.e. regulates CA Cal. DoHS has primacy (i.e. regulates CA systems)systems)

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DBPs and Health EffectsDBPs and Health Effects

• Some DBPs are suspected human Some DBPs are suspected human

carcinogens carcinogens (chronic exposure).(chronic exposure).

• Certain brominated DBPs suspected to cause Certain brominated DBPs suspected to cause

birth defects birth defects (acute exposure)(acute exposure)

• Only a few of the hundreds of DBPs have Only a few of the hundreds of DBPs have

been characterized with regard to health been characterized with regard to health

effects effects (e.g., only 8% of ozone DBPs)(e.g., only 8% of ozone DBPs)

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Utilities Must Balance Need to Disinfect

with Need to Reduce DBP Formation

• Enhanced Surface Water Treatment RuleEnhanced Surface Water Treatment Rule – requires disinfection – requires disinfection

• Disinfectants/Disinfection By-Products RuleDisinfectants/Disinfection By-Products Rule – places limits on – places limits on

TTHM, HAA5, & BromateTTHM, HAA5, & Bromate

DBP Health Effects

Disinfection for pathogen control

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DBP Formation Needs to Be Controlled Through a Combination

of Efforts

Source Water Treatment Plant Distribution System

Change Disinfectant Change Disinfectant or Application Pointor Application Point

Source WaterSource WaterChange orChange or

ManagementManagement

DistributionDistribution SystemSystem

ModificationsModifications

PrecursorPrecursor RemovalRemoval

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Water Quality Variability is Water Quality Variability is ProblematicProblematic

• Delta water has higher levels of bromide than 90-Delta water has higher levels of bromide than 90-95% of all national drinking water sources95% of all national drinking water sources– Bromide in the Delta ranges from 0.1 - 0.5 mg/LBromide in the Delta ranges from 0.1 - 0.5 mg/L– TOC in the Delta ranges from 3 - 7 mg/LTOC in the Delta ranges from 3 - 7 mg/L

• High bromide & TOC in Delta water requires urban High bromide & TOC in Delta water requires urban agencies to use complicated treatment processes agencies to use complicated treatment processes to ensure compliance with safe drinking water act to ensure compliance with safe drinking water act regulationsregulations

• Treatment strategy used affects the types and Treatment strategy used affects the types and concentrations of DBPs producedconcentrations of DBPs produced

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Treatment Process Affects the Type Treatment Process Affects the Type and Concentration of DBPs Producedand Concentration of DBPs Produced

0

10

20

30

40

50

60

70

80

90

100

110

Treatment Plant

Co

nce

ntr

ati

on

(u

g/l

)

TTHM HAA5 Bromate

chloramineozone

chloramine

chlorine

chlorine

MIOX

chlorine ozone

chlorine

MWD VALLEJO

Benchmark TTHM

BenchmarkHAA5

Benchmark Bromate

CLAWA

chlorine

(2000 - 2004)

Mills Treatment Plant - ozone 4th quarter 2003. *Some missing data**Planned switch to ozone

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Source Water Goals for Delta Source Water Goals for Delta WaterWater

• SWRCB 1991 Water Quality Control PlanSWRCB 1991 Water Quality Control Plan– Found that agencies should “strive to obtain bromide Found that agencies should “strive to obtain bromide

levels of 0.15 mg/L or less (about 50 mg/L chloride in levels of 0.15 mg/L or less (about 50 mg/L chloride in

the Delta).”the Delta).”

• CALFED Water Quality GoalCALFED Water Quality Goal (CALFED ROD)(CALFED ROD)

– 50 50 µµg/L of bromide (equivalent to <20 mg/L chloride)g/L of bromide (equivalent to <20 mg/L chloride)– 3.0 mg/L of TOC3.0 mg/L of TOC– Or Equivalent Level of Public Health ProtectionOr Equivalent Level of Public Health Protection– Based on the 1998 CUWA expert panel Based on the 1998 CUWA expert panel

recommendationsrecommendations

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Delta Source Water GoalsDelta Source Water Goals (continued)(continued)

• SWRCB 1995 Water Quality Control PlanSWRCB 1995 Water Quality Control Plan

– 250 mg/L chloride is about 850 250 mg/L chloride is about 850 µµg/L bromideg/L bromide

– 150 mg/L chloride is about 520 150 mg/L chloride is about 520 µµg/L bromideg/L bromide

– Nowhere near CALFED’s 50 Nowhere near CALFED’s 50 µµg/L bromide goal g/L bromide goal

• SWRCB has not yet adopted water quality SWRCB has not yet adopted water quality

objectives for drinking water protectionobjectives for drinking water protection

– e.g., disinfection byproduct precursors, or e.g., disinfection byproduct precursors, or

pathogenspathogens

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Proposed Stage 2 DBP Rule Sets Proposed Stage 2 DBP Rule Sets LocationalLocational Running Annual Average Running Annual Average

for Compliance for Compliance

• Promulgation expected in Summer 2005Promulgation expected in Summer 2005

• System-wide averaging will no longer be allowed System-wide averaging will no longer be allowed

• Creates less room for error in process control for Creates less room for error in process control for

for agencies treating Delta waterfor agencies treating Delta water

• Creates more compliance risk with prolonged Creates more compliance risk with prolonged

source water quality swingssource water quality swings

• Regulation phases in through about 2011. Regulation phases in through about 2011.

Slide 15

ConclusionsConclusions

1.1. Disinfection Byproducts (DBPs) are a greater public Disinfection Byproducts (DBPs) are a greater public

health issue than in 1991. Ahealth issue than in 1991. Additional DBPs likely to be dditional DBPs likely to be

regulated in future and DBP regulations will become regulated in future and DBP regulations will become

more stringent.more stringent.

2.2. Will be more difficult and expensive to comply with Will be more difficult and expensive to comply with

drinking water regulations. drinking water regulations.

3.3. Utilities cannot rely on treatment alone – need a multi-Utilities cannot rely on treatment alone – need a multi-

barrier approach, consistent with CALFED drinking barrier approach, consistent with CALFED drinking

water goalwater goal 50 ug/L bromide and 3 mg/L TOC or an equivalent 50 ug/L bromide and 3 mg/L TOC or an equivalent

level of public health protectionlevel of public health protection. .