Rural Community Assistance Partnership Practical solutions for improving rural communities

Micro-Contaminants: Sources, Controls and Treatment Methods

Neil Worthen, RDS Environmental Rural Community Assistance Corporation (RCAC)

WELCOME!

This training was funded as part of the EPA/RCAP Training/Technical Assistance to Improve Water Quality Project

1 Your Moderator Today…

John Hamner Kelseyville CA [email protected]

The Rural Community Assistance Partnership

RCAC

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2 RCAC Programs

 Affordable housing  Community facilities  Water and wastewater infrastructure financing (Loan Fund)  Classroom and online training  On-site technical assistance  Median Household Income (MHI) surveys

Time For a Quiz!

3 Your Presenter Today…

Neil Worthen Las Cruces, NM [email protected]

What “Micro-contaminants” Are We Talking About? Arsenic Disinfection By-Products (DBPs) Lead and Copper – As they relate to the distribution system

4 What’s In A Name??

Why just these four? Couldn’t all contaminants be considered micro-contaminants?

How Did This Stuff Get In My Water?

Erosion of natural deposits Human activity Chemical reactions during treatment and distribution Corrosion of pipes & fixtures

5 What Is Arsenic?

A metalloid element, or chemical compounds containing arsenic

Human Exposure

 Average 20 µg/day from food, air and water  Arsenic is readily excreted from the body (3-5 day half life)

 The 20th most abundant element in the earths crust, and is the 12th most abundant element in the human body

6 Current Use

 Use is dropping because of toxicity  90% used as wood preservative (although this too is being phased out)  Silicon based computer chips  Feed additive (poultry and swine)  Cotton fields  Chemotherapeutic

Arsenic In Drinking Water (Inorganic)

 Trivalent (As3+) – arsenic trioxide, sodium arsenite – arsenic trichloride  Pentavalent (As5+) – arsenic pentoxide, arsenic acid, – arsenates (lead arsenate)

7 Chronic Toxicity

 Chronic exposure (drinking water) – Skin cancer (recognized >100 years ago) – Garlic odor on breath – Excessive perspiration – Muscle tenderness and weakness

Chronic Toxicity

 Changes in skin pigmentation  Paresthesia (numbing) in hands and feet  Peripheral vascular disease  Gangrene of feet – Blackfoot disease

8 Chronic Toxicity

 Drinking water at “low” levels of <100 µg/L (ppb) – Lung Cancer – Bladder Cancer – Skin lesions – Anemia – Nerve damage

Susceptibility & Variability

 Children – small size, higher water consumption for size

 Genetic

 Age

 Nutrition

9 US Arsenic Map

Safe Drinking Water Act

 USEPA - Drinking water MCL 10 µg/L (ppb) or 0.010 mg/L (ppm)  If any water sample, past or present, has exceeded 10 ppb, a system may be out of compliance  Additional information • US Environmental Protection Agency (EPA) – www.epa.gov

10 CCR Educational Statement

“While your drinking water meets EPA’s standard for arsenic, it does contain low levels of arsenic. EPA’s standard balances the current understanding of arsenic’s possible health effects against the costs of removing arsenic from drinking water. EPA continues to research the health effects of low levels of arsenic which is a mineral known to cause cancer in humans at high concentrations and is linked to other health effects such as skin damage and circulatory problems.”

CCR Health Effects Statement

Some people who drink water containing arsenic in excess of the MCL over many years could experience skin damage or problems with their circulatory system, and may have an increased risk of getting cancer

11 Violation Determination

 Systems triggered into increased monitoring are not in violation until they have completed one year of quarterly sampling  Any sample result that causes the RAA to exceed the MCL will be out of compliance immediately  If a system does not collect all required samples, compliance will be based on the running annual average of the samples collected

Monitoring

 If no water sample, past or present, has exceeded 0.010 ppm (10 ppb) As analysis every three years (State authorities may require more often)  If a single water sample, exceeds 0.010 ppm (10 ppb) – Quarterly monitoring, beginning the next quarter after the results were received

12 Benefits Of Lower As Standard

 Reducing As from 50 µg/L to 10 µg/L will prevent: • 19-31 cases of bladder cancer (in US per year) • 5-8 deaths due to bladder cancer • 19-25 cases of lung cancer • 16-22 deaths due to lung cancer

How Do I Get Rid Of This Stuff?

Hmmmm...... Arsenic!

Now what do I do??

13 Mitigation Techniques

 Alternative source  Blending  Centralized treatment – Techniques • Side-stream treatment • Full treatment  Existing technologies  New technologies  Point-of-use (POU)

USEPA “Best Available Technology” (BAT)

14 Small System Compliance Technologies

Waste Streams

Liquid Residuals Solid Residuals – Brine – Spent resins – Backwash water – Spent media – Rinse water – Spent membranes – Concentrate – Sludges

15 Questions To Ask

 Will there be waste?  Will it be Hazardous Waste? – Yes if listed as such or demonstrates hazardous characteristics  How can you dispose of the waste? – Non-hazardous • Many options – Hazardous • Options more limited and expensive

Questions For Your Engineer

 How many arsenic treatment plants have you designed/installed?  How effective is the chosen treatment technology?  How much are the capital costs?  How much will the operations and maintenance costs be per gallon of water treated (including residual disposal costs)?  Can you provide plant operation training?

16 Questions For Vendors

 Are there any arsenic treatment plants currently operating that use your technology?  Can you demonstrate that your technology works with my water chemistry?  Can you guarantee what the cost per gallon of water treated will be?

Questions / Discussion

17 What Exactly Are Disinfection Byproducts (DBPs)?  Chemical compounds created when chemical disinfectants combine with naturally occurring organic/inorganic “precursors”  Can change day to day based on: – Season – Water temperature – Amount of disinfectant added – Quantity and types of organics

What Exactly Are Disinfection Byproducts (DBPs)? (cont.)

 Total Trihalomethanes (TTHM)  Haloacetic acids (HAA5)  Bromate – Systems that use ozone  Chlorite – Systems that use chlorine dioxide  Dozens more that are unregulated

18 How Are DBPs Formed?

 Chlorine + organics = THM & HAA5  Ozone + Bromide = Bromate  Chlorine + Triclosan = Chloroform  Ultraviolet + organics = no DBPs

DBP Health Effects

 Long-term exposure – Bladder cancer – Colon & rectal cancers  Short term exposure at high levels – Reproductive and developmental health effects

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19 Stage 1 DBPR Effective Dates:

 Surface water systems serving population more than 10,000 – January 1, 2002  Surface water systems serving population less than 10,000 and systems using groundwater not UISW – January 1, 2004

Stage 1 MCLs Total Trihalomethanes (TTHMs)

Disinfection Maximum Detection Level for Byproduct Contaminant Level Reporting Total Trihalomethanes 0.080 mg/L 0.005 mg/L

Bromoform 0.005 mg/L

Chloroform 0.005 mg/L 0.080 mg/L Total Dibromochloromethane 0.005 mg/L

Bromodichloromethane 0.005 mg/L

20 Stage 1 MCLs

Haloacetic Acids (HAA5) Disinfection Maximum Detection Level for Byproduct Contaminant Level Reporting Total Haloacetic Acids 0.060 mg/L 0.005 mg/L Monochloroacetic Acid 0.005 mg/L Dichloroacetic Acid 0.005 mg/L Monobromoacetic Acid 0.060 mg/L Total 0.005 mg/L

Dibromoacetic Acid 0.005 mg/L

Trichloroacetic Acid

Maximum Residual Disinfectant Level (MRDL) And Maximum Contaminant Levels (MCLs)  MRDL Disinfectants MRDL (mg/L) Chlorine* 4.0 Chloramines* 4.0 Chlorine Dioxide 0.8

 MCLs Disinfection Byproducts MCL (mg/L)

Bromate* 0.010 Chlorite 1.0 TTHM 0.080 HAA5 0.060

* Based on running annual average

21 Who Must Comply With The DBP Rules? Community and Non-transient water systems Disinfects or delivers disinfected water Transient systems that use chlorine dioxide Does NOT apply to systems using only UV

How Do I Get Rid Of This Stuff?

Hmmmm...... DBPs!

Now what do I do??

22 DBP Chemistry - Precursors

 Natural Organic Matter (NOM) – Occurs in all surface water, decayed plant and animal matter  Total Organic Carbon (TOC) – Includes NOM, pesticides, petroleum, etc  Dissolved Organic Carbon – The largest fraction of TOC, and of the most concern

THM Formation Factors

.THM precursors (humic and fulvic acids) .Chlorine addition point .Chlorine concentration .Level and type of organics .pH of water in system: Higher pH = in THMs .Residence time (MRT) .Temperature

23 HAA5 Formation Factors

.HAA5 precursors .Chlorine addition point .Chlorine concentration

.pH of water in system: Low pH = in HAA5 .Temperature

DBP Reduction Measures

 Remove precursors  Modify treatment  Change type or dose of disinfectants or oxidants  Change points of application of disinfectants or oxidants  Examine storage design, O & M  Manage distribution system

24 Removing TOC Precursors

 New source  Source water protection  Treat algae blooms  PAC or GAC  Ion exchange  Reverse osmosis

Removing TOC Precursors

 Oxidize TOC with – Ozone, chlorine dioxide, chlorine – Hydrogen peroxide – UV light (photolysis) – Potassium permanganate – Other?

25 Modify Treatment

 Modify conventional treatment to optimize TOC removal  Change contact basin geometry and/or baffling (adequate mixing)  Provide adequate contact time to achieve disinfection  Lower pH at chlorine application point (better disinfection/reduced dosage)

26 DBP Reduction Measures

 Changing type and dose of disinfectant – Examine points of application – know why are you adding that chemical at that point – Change disinfectant chemical – Use multiple disinfectants – Reduce dosage – Add disinfectant further downstream

27 DBP Reduction: Distribution System Management  Loop dead end mains  Chlorine booster stations in distribution system  Flushing program  Automatic flush valves  Cross connection control

28 DBP Reduction: Distribution System Management  Treat biofilms – Swabbing/pigging – Shock chlorination – Corrosion control chemicals – Appropriate residual disinfectant

Franchi and Hill, 2002

29 DBP Reduction: Distribution System Management  Examine storage tanks design and O&M – Design inlets/outlets to maximize turbulence & mixing – Reduce retention time – Ensure turnover (mechanical mix?) – Remove sediments/biogrowth

Sediment In Storage Tanks

 Contains organic nutrients for micro-organisms  Exerts disinfectant demand  Taste/odor  Harbor pathogens and nitrifying bacteria  Can contribute to disease outbreaks

30 Storage Tank Turnover Goals

 20 - 30% of total volume daily  50% turnover daily is ideal  Complete turnover at least every 72 hours

31 Resources

• U.S. EPA Complying with the Stage 2 DBP Rule: Small Entity Compliance Guide http://www.epa.gov/ogwdw/disinfection/stage2/pdfs/guide_ st2_stepguide_smallentitycomplianceguide.pdf

• U.S. EPA Stage 2 DBP Rule – Operational Evaluation Guidance Manual http://www.epa.gov/ogwdw/disinfection/stage2/pdfs/draft_g uide_stage2_operationalevaluation.pdf

Resources

 EPA STEP Guide for Stage 2 DBPR Compliance  EPA Stage 2 Fact Sheets (Schedule 1 through 4 systems):

– www.rcac.org - Follow the links to Workshop Materials  EPA Stage 2 DBPR web page: – http://www.epa.gov/safewater/disinfection/stage2/

32 Questions / Discussion

Lead and Copper

How does lead and copper end up in our water when it wasn’t there to begin with??

33 Answer: Corrosion!

LCR Overview Health Effects of Lead

 Children are highly susceptible – Impaired mental development – IQ deficits – Shorter attention span – Lowered birth weight – Altered hemoglobin synthesis and Vitamin D metabolism  Adults – Increased blood pressure  EPA set MCLG at zero

34 LCR Overview Health Effects of Copper  Stomach and intestinal distress  Complications of Wilson’s Disease  Chronic exposure can cause liver disease in genetically predisposed individuals  EPA set MCLG at 1.3 mg/L

LCR Overview

 Published on June 7, 1991  Establishes MCLGs for lead and copper  Mandates treatment techniques vs. MCL, triggered by tap monitoring results >AL

MCLGs Action Levels (ALs) Lead 0 mg/L 0.015 mg/L Copper 1.3 mg/L 1.3 mg/L

*AL Exceedance is not a violation

35 LCR Overview

Lead and Copper Tap Monitoring

No Lead Copper Exceedance* Exceedance Exceedance

Treatment Technique Requirements Treatment Technique Req’ts

Periodic Public CCT SOWT LSLR CCT SOWT Monitoring Edu.

* includes systems serving  50,000 people and (b)(3) systems.

Review of Monitoring Requirements Minimum Number of Tap Samples

Number of Number of System Sampling Sites Sampling Sites Population (Initial / Routine (Reduced Monitoring) Monitoring) >100,000 100 50 10,001 to 100,00 60 30 3,301 to 10,000 40 20 501 to 3,300 20 10 101 to 500 10 5 ≤100 5 5

36 Review of Monitoring Requirements Sample Site Selection  A tap that is “normally” used for human consumption: – Typically cold water kitchen or bathroom sinks – Drinking fountains and water coolers in schools or other buildings  Do not sample from outside hose bibs or utility sinks

Review of Monitoring Requirements Sample Collection Method First-draw samples Minimum 6-hour standing time One-liter volume System or residents can collect

37 Review of 90th Percentile Calculations More than 5 Samples • Step 1: Place lead or copper results in ascending order • Step 2: Multiply the total number of samples by 0.9 Example: 20 samples x 0.9 = 18th sample • Step 3: Compare 90th percentile level to AL

Review of 90th Percentile Calculations More than 5 Samples Example Step 1: Order results from lowest to highest: 1. Site A: 0.005 6. Site E: 0.014 2. Site C: 0.005 7. Site H: 0.014 3. Site F: 0.005 8. Site I: 0.014 4. Site J: 0.005 9. Site B: 0.015 5. Site D: 0.014 10. Site G: 0.040

Step 2: Multiply number of samples by 0.9 to determine which represents 90th percentile level 10 x 0.9 = 9th sample (or 0.015 mg/L) Step 3: Compare to lead action level  No exceedance

38 Review of 90th Percentile Calculations 5 Samples Example Step 1: Order results from lowest to highest: 1. Site A: 0.009 mg/L 2. Site D: 0.009 mg/L 3. Site E: 0.010 mg/L 4. Site B: 0.011 mg/L 5. Site C: 0.020 mg/L Step 2: Average 4th & 5th samples highest samples to get 90th percentile value = 0.016 mg/L 0.011 mg/L + 0.020 mg/L = 0.0155 mg/L 2 Step 3: Compare average to lead action level  Exceedance!

Review of 90th Percentile Calculations Fewer than 5 Samples • Procedure has changed under LCR STR • Some systems may collect < five samples • Sample with highest result is 90th percentile level

• Assume 3 lead samples: • 0.020 mg/L, 0.008 mg/L, and 0.005 mg/L • 90th percentile = 0.020 mg/L

39 How Do I Get Rid Of This Stuff?

Hmmmm...... Lead and Copper!

Now what do I do??

What Is Corrosion?

 The wearing away or deterioration of material because of chemical reactions with it’s environment  Corrosion can occur with almost any metal that is exposed to water, depending on: – Type of metal – Chemical and biological character of the water – Electrical characteristics of the metal

40 Corrosion Chemistry

 Factors influencing corrosion – Dissolved oxygen (DO) – Total dissolved solids (TDS) – Alkalinity and pH – Temperature – Flow velocity – Type of metal – Electrical current

Corrosion Chemistry

 Factors influencing corrosion (continued) – Bacteria

• Carbon dioxide (CO2) or hydrogen sulfide (H2S) • Slimes – Iron bacteria • Gallionella and Crenothrix – Sulfur bacteria • Desulfovibrio desulfuricans

41 Corrosion Chemistry

 Iron Bacteria – Deposit large volumes of slimes – Thrive on naturally occurring iron or iron from pipe corrosion

– CO2 builds up beneath the slime layer – Sloughing of slime accumulations causes taste and odor problems – Sloughing carries away scale buildup

Corrosion Chemistry

 Sulfur Bacteria

– Reduce sulfate (SO4) in the water under anaerobic conditions, producing:

• Iron sulfide (Fe2S2)

• Hydrogen sulfide (H2S)

42 Corrosion Chemistry

 Corrosion factors interact with each other in the treatment plant, distribution system, and customers plumbing  As factors change, corrosion changes  The only factors an operator can control are: – pH – Alkalinity – Bacteriological content of water

Types Of Corrosion

 Localized corrosion – Most common type – Attacks metal surfaces unevenly – Leads to more rapid failure of the metal • Galvanic corrosion • Concentration cell corrosion  Uniform corrosion – Affects entire surface at an even rate – Occurs with low pH and alkalinity on unprotected surfaces

43 Corrosion Control Methods

 Adjust pH and alkalinity  Deposit calcium carbonate coating  Deposit sodium silicate coating  Use corrosion inhibitors and sequestering agents

* See pages 271 & 272 of AWWA’s WSO: Water Treatment for a summary of treatment techniques for controlling corrosion and scaling

Adjustment of pH and Alkalinity

 A moderate increase in pH and alkalinity can decrease corrosion – Lime – Soda ash – Sodium bicarbonate – Caustic soda  A moderate decrease in pH and alkalinity can decrease scale formation – Carbon dioxide – Sulfuric acid

44 Corrosion Inhibiters & Sequestering Agents

 Polyphosphates – Sequester (chemically “tie up”) calcium and magnesium ions – Sequester iron  Silicates  These chemicals will eventually be ingested by consumers! – Must comply with NSF and AWWA standards

Determining The Best Corrosion Control Treatment  Consult with the state  Obtain recommendations of chemical suppliers  Check with industries, hospitals, clinics, and wastewater plants  Check with other water systems  Don’t experiment on the whole system  Consider advantages and disadvantages of storing, handling and feeding various chemicals

45 Operation Of Stabilizing Processes

 Lime coating – Maintain alkalinity and calcium at a minimum

of 40 mg/L as CaCO3 – Keep water 4 – 10 mg/L oversaturated with

CaCO3 – Keep pH between 6.8 and 7.3

Operation Of Stabilizing Processes

 Polyphosphate coating – Dosage ranges from 0.5 to 3.9 mg/L (sodium zinc phosphate or zinc orthophosphate) – Dose as high as 10 mg/L for sodium hexametaphosphate  Sodium silicate – Dosage ranges from 15 to 30 mg/L initially, then reduced to 5 to 10 mg/L

46 Operational Controls

 In plant water quality monitoring – pH entering distribution system – continuously – Raw water pH, total alkalinity – every 8 hours – Langelier saturation index (or CCPP) of raw and treated water – calculated daily  Distribution system monitoring – Types of analysis depend on pipe materials (see page 288, AWWA’s WSO: Water Treatment) – Pipe and coupon testing

Questions / Discussion

47 Time For a Quiz!

Thank You For Attending!

Neil Worthen [email protected] (575) 527-5372

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