EPA’s Office of Research and Development and Office of Water invite you to a free webinar

Corrosion Control for Drinking Water Systems Tuesday, July 28, 2015 2:00 to 3:00 pm EST Treatment, control, and assessment strategies for lead and copper release into drinking water This presentation is an overview of the most important water treatment strategies for the control of lead and copper release from drinking water plumbing materials and components. In addition to lead, copper, and combined treatment, this presentation will also cover sampling to find lead and copper, the stagnation behavior of copper versus that of lead, the impact of pipe scale aging on copper release, and complications of metal contamination arising from accumulated deposits of iron, manganese, and aluminum on the lead or copper pipe surfaces. An overview on the nature of scales and deposits on lead and copper pipes in real water systems, which often differ from classical corrosion theory, and the implications for metal release control by requiring the addressing optimization of interacting treatment processes to assure simultaneous compliance will also be presented.

A certificate for one continuing education contact hour will be offered for this webinar

Presented by Michael R. Schock – EPA’s Office of Research and Development (ORD). Mike is a chemist with ORD’s National Risk Management Research Laboratory in Cincinnati, OH. He has spent 30 years of his career conducting drinking water research, including both in-house and field research into drinking water treatment with emphasis on metal release mechanisms and predictive modeling, corrosion control, pipe scale/sediment and inorganic water analysis, contaminant accumulation and water quality in domestic plumbing and municipal distribution systems, and development of sampling strategies for metal contamination in building and premise plumbing. He has served on numerous advisory committees and has received more than 20 publication and research awards from EPA, New England Water Works Association, and the American Water Works Association, including the 2011 A.P. Black Research Award for lifetime achievement.

Requirements for optimizing corrosion control treatment This presentation will provide an overview of the existing requirements regarding Optimizing Corrosion Control Treatment in EPA’s Lead and Copper Rule, including monitoring requirements and corrosion control treatment methods.

Presented by Brian D’Amico – EPA’s Office of Water. Brian is a chemical engineer who has spent the last ten years at EPA working on water regulations for both the Safe Drinking Water Act (SDWA) and the Clean Water Act. He is currently the team lead for the Regulations Implementing Section 1417 of the SDWA. Prior to his transition to drinking water, Brian worked on several effluent guidelines, including airport deicing and unconventional oil and gas.

Webinar Registration: https://attendee.gotowebinar.com/register/5651769410281471234

Who should attend?

State primacy agencies, tribes, community planners, technical assistance providers, academia, and water systems interested in issues facing community water systems and solutions to help solve them.

In 2015, EPA’s Office of Research and Development and Office of Water will host monthly webinars to discuss challenges and treatment solutions for small drinking water and wastewater systems.

EPA 2015 Monthly Webinar Series: Challenges and Treatment Solutions for Small Drinking Water and Wastewater Systems All webinars will take place from 2:00 to 3:00 pm EST January 27

Arsenic Treatment Technologies (COMPLETE)

February 24

Innovative Biological Treatment for Small Water Systems: Ammonia, Nitrites, and Nitrates (COMPLETE)

March 31

Small Water System Alternatives: Media and Membrane Filtration for Small Communities and Households (COMPLETE)

April 28

Understanding End Water Quality in Hospitals and Other Large Buildings (COMPLETE)

May 26

Current Water Treatment and Distribution System Optimization for Cyanotoxins (COMPLETE)

June 30

Biological and Microbial Aspects of Septic System Pollution (COMPLETE)

July 28

Corrosion Control for Drinking Water Systems (COMPLETE)

August 18

Distribution Operation Options for Small Systems to Address DBPs

September 29

UV Disinfections Systems – Treatment of Groundwater for Small/ Medium Sized Water Utilities

October 27

Decentralized High-Rate Wastewater Treatment of Peak Wet Weather Flows

November 24

Treatability Databases, Cost Models, and Other Tools for Water Systems

December 15

Reduction of Lead in Drinking Water

Upcoming webinar registration and past webinar recordings: http://www2.epa.gov/water-research/2015-small-systems-webinar-series (Certificates of completion cannot be given for viewing webinar recordings.)

2015 Monthly Webinar Series: Challenges and Treatment Solutions for Small Drinking Water and Wastewater Systems Presented by EPA’s Office of Research and Development and Office of Water

June 30, 2015 from 2:00-3:00 PM EST (Optional Q&A session from 3:00-3:30)

TODAY’S TOPIC:

Corrosion Control for Drinking Water Systems Webinar Support Phone Number: 1-800-263-6317 Audio Controls: Your audio is muted by the organizer To Ask a Question: Type question in text box located in the lower section of your screen If you did not request the credit at registration, send email request to [email protected] or respond to your registration confirmation email

Certificate of Completion for

One Contact Hour

Requirements: 1. You must be registered for the live webinar or be in a room with someone who is registered. 2. You must attend for a minimum of 60 minutes. 3. If in a room with others, the names of people not logged in must be provided by the person who is logged in. (Send names to [email protected])

Certificates of completion cannot be given for webinar recordings

Today’s EPA Speakers

Michael R. Schock (ORD)

Brian D’Amico (OW)

Will present on treatment, control, and assessment strategies for lead and copper release into drinking water.

Will provide an overview of existing requirements regarding optimizing corrosion control treatment in EPA’s LCR.

Mike is a chemist who has spent 30 years of his career conducting drinking water research, including both in-house and field research into drinking water treatment with emphasis on metal release mechanisms and predictive modeling, corrosion control, pipe scale/sediment and inorganic water analysis, contaminant accumulation and water quality in domestic plumbing and municipal distribution systems, and development of sampling strategies for metal contamination in building and premise plumbing. He has served on numerous advisory committees and has received more than 20 publication and research awards from EPA, New England Water Works Association, and AWWA, including the 2011 A.P. Black Research Award for lifetime achievement.

Brian is a chemical engineer who has spent the last ten years at EPA working on water regulations for both the Safe Drinking Water Act (SDWA) and the Clean Water Act. He is currently the team lead for the Regulations Implementing Section 1417 of the SDWA. Prior to his transition to drinking water, Brian worked on several effluent guidelines, including airport deicing and unconventional oil and gas.

Contact: [email protected]

Contact: [email protected]

Lead and Copper Rule Optimized Corrosion Control

Brian D’Amico U.S. EPA Office of Ground Water and Drinking Water 1

Purpose • Provide background on the existing LCR requirements, including optimized corrosion control provisions.

U.S. Environmental Protection Agency

2

Background • The Lead and Copper Rule (LCR) is a treatment technique rule •

The regulation requires systems to take certain actions to minimize lead and copper in drinking water as opposed to meeting an MCL.

• It requires public water systems (PWSs) to monitor for lead and copper. • •

While there are no MCLs associated with the LCR rule it does establish Action Levels (0.015 mg/L for lead or 1.3 mg/L for copper). If the Action Level is exceeded it triggers additional actions to reduce water corrosivity, provide public education and remove lead service lines, if necessary. U.S. Environmental Protection Agency

3

Existing Monitoring Requirements •

Both community water systems (CWSs) and non-transient noncommunity water systems (NTNCWSs) are subject to monitoring requirements for Lead and Copper

•

Systems must collect first-draw samples at taps in homes/buildings that are at high risk of lead and copper contamination

•

The number of required samples varies by the size of the population served by the system

• •

Systems serving > 100K people are required to take 100 samples Systems serving ≤100 people are required to take 5 samples

U.S. Environmental Protection Agency

4

Existing Monitoring Requirements (cont’d)

•

PWSs must conduct tap monitoring every 6 months unless they qualify for reduced monitoring

•

The number of required samples and sampling frequency may be reduced if systems meet certain requirements •

•

Monitoring may be as infrequent as once every nine years.

In the event a PWS exceeds designated action levels a PWS may be required to take corrective actions to minimize the levels of lead and copper in drinking water. • Some of these corrective actions may be required regardless of lead/copper levels for PWSs serving more than 50K people.

U.S. Environmental Protection Agency

5

Corrective Actions • When a PWS exceeds an Action Level they must conduct the following corrective actions: • • • •

Conduct public education Implement source water monitoring and if needed treatment Install or optimize corrosion control treatment (serving < 50K people) Implement Lead Service Line Replacement (LSLR)

• Lead service line replacement is only required only when corrosion controls do not reduce lead and copper levels below the Action Levels. • Some of the listed corrective actions are required of large PWSs (those exceeding 50K people served) regardless of levels of lead or copper. U.S. Environmental Protection Agency

6

Corrosion Control •

What is corrosion? • The International Union of Pure and Applied Chemistry (IUPAC) defines corrosion as: • An irreversible interfacial reaction of a material (metal, ceramic, polymer) with its environment which results in consumption of the material or in dissolution into the material of a component of the environment.

•

Why do PWSs want to control corrosion • Corrosion can cause dissolution of lead or copper in pipes into drinking water.

•

Corrosion control approaches in the lead and copper rule. • pH/Alkalinity adjustment • Corrosion inhibitor addition (e.g. orthophosphate, silica) • Calcium carbonate precipitation U.S. Environmental Protection Agency

7

•

Corrosion Controlling Treatment Methods

Increasing the pH of water may decrease the solubility of lead and copper in water. • •

•

Sodium Carbonate (NA2CO3), Lime (Ca(HO)2), and Sodium Hydroxide (NaOH) are three common agents used to increase the pH of drinking water. Higher pH in drinking water can cause disinfection byproducts (such as Chloroform) when chlorine based disinfectants are used to treat drinking water.

Injecting orthophosphates into the drinking water creates a coating of the corrosive sites on pipes. • • •

The coating hinders the ability of lead or copper to dissolve into the drinking water. There is an optimal pH range (7.2-7.8) to ensure proper orthophosphate coverage throughout the distribution system. Orthophosphate use may result in increased nutrients discharged to receiving waters. U.S. Environmental Protection Agency

8

Corrosion Controlling Treatment Methods (cont’d) • Precipitating calcium carbonate in water distribution system.

• Precipitation may be achieved through the addition of lime which will add calcium ions and increase pH.

• The calcium carbonate forms a protective scale on the distribution system piping preventing corrosion. • This is not a preferred method of corrosion control for PWSs • It is difficult to precipitate an even scale throughout the distribution system. • Precipitation may be heavy close to the treatment plant and there may be little to no scale precipitated at the ends of the distribution system. U.S. Environmental Protection Agency

10

Existing Corrosion Control Requirements • Most large PWSs (serving > 100K people) and medium and small systems that exceed either the lead or copper Action Level are required to optimize their corrosion control treatment (CCT). • All large PWSs and some small and medium PWSs are required to conduct a study of their system to determine the best CCT to install. • This study must be completed in 18 months. • Once the best CCT has been approved by the state, the PWS has 24 months to install the technology. U.S. Environmental Protection Agency

11

Corrosion Control Requirements (Cont’d) •

Systems installing CCT, must conduct follow-up monitoring for 2 consecutive 6-month periods. This monitoring includes both tap and entry point monitoring for • •

•

Lead and copper State designated water quality parameters which may include: pH, Alkalinity, calcium, conductivity, orthophosphate, silica, and temperature.

After follow-up monitoring has been completed, the State reviews the data and sets Optimal Water Quality Parameter (OWQP) specifications that define optimal CCT. • • • •

Compliance with the LCR is determined by meeting the OWQP Monitoring continues at the tap every six months and at the entry point to the distribution system every two weeks. Consistently meeting the OWQPs can reduce the frequency at which tap monitoring is required. Tap monitoring may be as infrequent as once every nine years. U.S. Environmental Protection Agency

12

Questions?

Treatment, control, and assessment strategies for lead and copper release into drinking water Michael Schock U.S. Environmental Protection Agency ORD, NRMRL, WSWRD, TTEB, Cincinnati, Ohio 45268

New Research View of Optimal Corrosion Control Treatment • OCCT includes both pure corrosion and control of metal release (what causes unhealthy exposures) • OCCT is much more than simply adjusting pH or adding phosphate. • The nature of pipe scales reflecting past treatment history dictates the direction and level of success of lead control approaches • Metal solubility is important factor – Varies by factor of 5 to 10 or more across systems – Is minimum chronic background exposure to consumers

• Both soluble and some particulate Pb release can be controlled by treatment, but episodic Pb spikes cannot be totally prevented when lead sources remain present. 5

“Corrosion Control” Treatment is Intertwined with All Treatments Affecting DS Water Chemistry To achieve OCCT, overall process control and distribution system water quality optimization must also be achieved. OCCT is not an independent, separate process.

6

We Know That…

Lead Pipes Won’t Go Away Any Time Soon Installed Right After the Civil War 150 Years Old in Cincinnati: Any Signs of Failure?

7

Pipe Scale Particles Have More Lead Than Pb in Paint or Soil

Erosion and suspension of particles from pipe corrosion scales and deposits is inevitable. Even minute amounts are greater relative exposure than paint or soils

8

8

General Factors Governing Pb Levels • Sampling protocol • Intrinsic Pb solubility of surface material (water chemistry) • Rate of dissolution in short stagnation times – Galvanic driving force – Diffusion from surface (reaches steady state)

• Length of contact with lead source • Nature of lead release – Particulate – Soluble

Additional point: There are no accurate substitutes or surrogate monitoring scenarios that can take the place of directly monitoring lead release. Corrosion “indices”, surrogate pipe rigs, and water quality parameters do not adequately predict lead levels at the taps.

9

9

LCR Widespread Misconceptions • WQPs meant to predict/control lead levels by themselves – Keep treatment from being turned off – Keep inhibitor dosages from being cut to save $$$ – Keep pH adjustment from being cut to save $$$ – Keep required repairs to treatment on tight schedule – Prevent willy-nilly variations in water sources

• Health effects in TT rules less serious than in MCL regulations – MCL not set because of unknowns about feasibility – MCLG = 0 – Risk estimations based on IQ detriments/BLL elevations point to MCL < PQL (0.005 mg/L) 10

The Ultimate Solution: Full LSL Removal

• The ORD collaborative research in Madison, WI showed that once the perpetual lead source was removed (the LSL), there was a lag time resulting from the reservoir of lead in the ironand manganese-rich deposition that accumulated in the premise plumbing. • The premise lead release reduced dramatically following full LSL replacement, but it took around 4 years. • Published and presented studies by others in Guelph (ON) and Halifax (NS) without the surface fouling deposits, showed nearly immediate total reductions in lead release from the premise plumbing. 11

There Are Many Types of Scale on Pb Pipe

• • • • •

Simple carbonate or hydroxycarbonate Pb(II) mineral Simple Pb(II) orthophosphate mineral Simple PbO2 solid phase, by itself or mixed with Pb(II) phases Mix of Pb(II) phases Protective “diffusion barrier” materials – Could be insoluble amorphous Pb(II) phase – Adherent non-Pb phase

• Surface fouling deposit – Primarily not made of lead, usually not crystalline – Lead may sorb to surface – Often not adherent 12

Low DIC/High pH Strategy More Difficult with LSLs than Leaded Solder or Brass It is only possible to nearly minimize Pb levels at pH >> 9. Can only work in “soft” waters.

•

Likely never as good as PbO2 or orthophosphate

•

Sufficient DIC (similar to alkalinity) is necessary to form protective scale, but too much resolubilizes lead

•

Formation of Pb(II) carbonate or hydroxycarbonate much faster than formation rate of Pb(II) orthophosphate films

•

•

Formation of Pb(II) hydroxycarbonate solid is a precursor to the formation of lesssoluble protective films of either Pb(II) orthophosphates or PbO2 The first formed solids with major treatment change.

100 1 mg C/L 5 mg C/L 10 mg C/L 20 mg C/L 35 mg C/L 50 mg C/L 75 mg C/L 100 mg C/L

10

mg Pb/L

•

1 0.1 0.01

6

7

9

8

10

11

pH 13

#

[Seemingly] New Ideas on pH/DIC Relation to Orthophosphate Dosing

“Point of Diminishing Returns” is key to costeffective lead release control and exposure reduction, if secondary interferences are removed

14

Effectiveness Depends on Dose, DIC, pH and “Cleanliness” of Pipe Surface 0.40 pH = 7.0 pH = 7.5 pH = 8.0 pH = 8.5

0.35

mg Pb/L

0.30

Most PWSs with LSLs currently do not have optimized corrosion control treatment in terms of minimizing Pb release and exposure.

0.25

•More effective with low TIC •Lower dosages at low TIC •pH less critical at low TIC •pH less critical at high PO4 •Point of diminishing returns higher with high TIC

0.20

48 mg C/L

0.15 0.10

4.8 mg C/L

0.05 0.00 0.0

Typical UK Dosages: 4-6 mg/L 1.0

2.0

3.0

mg PO4/L

4.0

5.0 15 15

Example of Pb Reduction by Increased Dosages 120

0 .6

10 0

g Pb/L

80

(Dosages: mg PO4/L)

60 40

1.2

20

1.8

2.5

0

3.0 0

5

10

15

20

25

30

Elapsed Days Replotted from Colling, et. al. (1992); pH, DIC unspecified, but can inferred to be 7-8 and 150-300 mg/L as CaCO3, respectively 16

Aggregated UK Lead Monitoring Data Two-pronged approach: (1) Initial dose estimation by pipe rig study for background water (2) RDT tap monitoring to assess progress & exposure

mg/L as PO4 = 3 x mg/L as P Cardew, P. T. Measuring the benefit of orthophosphate treatment on lead in drinking water. J Water Health 2009, 7 (1), 123-31.

17

UK Decade of Progress: Works on more than LSLs RDT sampling protocol

Cardew, P. T. Measuring the benefit of orthophosphate treatment on lead in drinking water. J Water Health 2009, 7 (1), 123-31.

18 18

Effect of pH and PO4 on Pb Release

DIC = 10 mg C/L, 1 mg PO4/L

10

Dissolved Pb with ortho-P Total Pb with ortho-P Dissolved Pb with CO3 Total Pb with CO3

Pb mg/L

1

At low DIC, orthophosphate improves lead release regardless of pH

0.1

US Action Level

0.01 0.001 6.0

6.5

7.0

7.5

8.0

8.5

9.0

9.5

pH Schock, M. R.; DeSantis, M. K.; Metz, D. H.; Welch, M. M.; Hyland, R. N.; Nadagouda, M. N. Revisiting the pH Effect on the Orthophosphate Control of Plumbosolvency, Proc. AWWA Annual Conference and Exposition, Atlanta, GA, 2008.

19

Orthophosphate Can Work at pH 9.0 (DIC 6 mg/L)

Pb (μg/L)

• Preliminarily, not necessarily same trend as at pH 7-8. • Pb may not decrease more with higher PO4 • Must do dose optimization study for your own water quality, especially at high pH Miller, S. A. Investigation of Lead Solubility and Orthophosphate Addition in High pH Low DIC Water. Master of Science, Department of Biomedical, Chemical, and Environmental Engineering, College of Engineering and Applied Science, University of Cincinnati, Cincinnati, OH, 2014.

20 20

Modes of PbO2 in LSL Scales About 1/3 of systems where scale was analyzed had some amount of PbO2

21

Pb Concentration (µg/L)

Example Profile of PbO2 Scale House 20 18 16 14 12 10 8 6 4 2 0

Cl1: Cincinnati, OH Plumbing sequence corresponding to water volume Faucet LSL Water Main M

Cu pipe

Brass

Cu pipe

CI-1, 10 h, 12/09 CI-1, 10 h, 04/10

-1 0

1

2 3 4 5 6 7 8 9 10 11 Cumulative Water Volume (L)

22

Chemical Changes Cause Dissolution of PbO2 1.2 1.0

PbO2 (plattnerite)

Drop in ORP from treatment change or DS oxidant demand

.8 .6

0.0 –.2

--

Pb(OH)42-

Drop in pH at surface from treatment change, chemical reactions, nitrification, etc.

.2

Pb(CO3)22-

++

Pb3(CO3)2(OH)2 (s)

Pb

PbCO3°

.4

Eh (volts)

Disinfectant demand in DS must be controlled and enough free chlorine consistently maintained throughout LSL area

DIC = 18 mg C/L Pb = 0.010 mg/L

–.4 –.6

Pb metal

–.8 -1.0 0

1

2

3

4

5

6

7

pH

8

9

10

11

12

13

14

23 23

Note on adding more of same disinfectant…

• Because LCR samples tend to be taken closer to 6 hours than 16 hours, they are disequilibrium samples • Adding more disinfectant may speed up rate at which lead is released, not necessarily changing the equilibrium solubility: Gives illusion of more corrosivity

24

Significant non-Pb Scale Components

May be more prevalent than “normal” lead solids across all systems

25

18 of 52 DWDS studied by EPA show external layer deposits almost completely made of poorly crystalline Mn, Fe, Al, Ca, or Si-rich phases

Adding orthophosphate or just adjusting pH with thick coatings likely will not minimize lead release until causes of the interfering buildups are controlled

26

26 26

Pb Profile of Sites with Al-Si-Ca Rich Deposit

Pb μg/L

< 10% Pb in surface scale, no crystalline Pb phases at surface

Liter in Sequence

27

Blended Phosphates: Not Same Mechanism as Orthophosphate (Chicago example analysis)

28 28

Impacts of Dissimilar Coatings • Sorption/entrainment of Cu or Pb • Continues exposure after LSLs removed • Degrades performance of phosphate inhibitors • Prone to particulate Pb/Cu release • Must understand treatment change impacts on coatings, as well as Pb and Cu • Cannot predict optimization or effectiveness of phosphate addition from theory, but can pilot test with exhumed pipes • Cannot form pure stable PbO2 layer • To control lead release, you must control Fe corrosion/deposition, finished water Mn, DBP precursors, coagulant carry-over, etc. 29

Manganese Deposit Removal Improves Lead Release (Marshfield, WI)

90

90th Percentile of LCR

75

60

Average of LCR N=30

45 N=30

Lead in Water-µg/L

30

N=61

LCR Lead Action Limit

15

0

2005

2008a

2007-present: Water main uni-directional flushing for lead control

2008b

N=30

N=60

To achieve OCCT, overall process control and distribution system water quality optimization must also be achieved. OCCT is not an independent, separate process.

Maximum of LCR round

220

2009

2010

2010: Not as much uni-directional flushing

Schock, M. R.; Cantor, A. F.; Triantafyllidou, S.; DeSantis, M. K.; Scheckel, K. G. Importance of Pipe Deposits to Lead and Copper Rule Compliance. Journal - American Water Works Association 2014, 106 (7), E336-E349.

30

Copper

31

Identifying Pb and Cu High Release Sites

As early as 1992, poor to no correlation between sites with high lead and high copper were being observed

Only in acidic oxic waters is there good agreement

Figure IV-13 1992 JMM EES PK Report

32 32

Science Issues with Current LCR Cu Sampling • Chemistry and mechanisms of Pb and Cu release have major differences • Newest Tier 1 copper sites are 25 years old and get older every monitoring round, exactly the opposite of copper release risk • If a site has an LSL, copper may be sampled from galvanized plumbing • States may deem “optimized” even if people have copper levels above the AL, for which there is no public notification • Water quality where sampling sites exist may be considerably different than where high copper levels exist • Site targeting does not try to capture aggressive waters.

33

Major Factors in Cu Release • ORP/persistence of oxidants • pH/Alkalinity/DIC = solubility • [Ortho]phosphate • Aging (several variables) • Stagnation time • Flow regime/surface area to volume ratio of real pipe installations versus simulation studies such as coupons (affects rate of aging and stagnation release) 34

No Copper Corrosion in Anoxic Waters

1000x INCREASE in Cu solubility for fresh Cu(II) vs Cu(I) at pH 7

35

Summary of Cu(II) Vulnerability (No PO4)

• New copper • Need pH > 7, any alkalinity • Never a problem from day of installation at higher pH’s, lower alkalinities • Copper levels depend on both pH and alkalinity (DIC) 36

Cu(II) Solubility & pH Adjustment

7.0

3.0

• If pH > 7.5, no problems if DIC < 35

7.5

• If DIC > 35-40, scaling & buffering prevents sufficient pH adjustment to solve problems • To minimize Cu for WWTP discharge optimization, pH > 9 needed

mg Cu/L

• If DIC < 5, no problems if pH > 7 2.0 ACTION LEVEL

1.0

8.0

0.0

8.5 9.0 9.5 10.0

0

10

20

30

40

50

60

70

mg C/L DIC 37 37

Cu Aging: The Missing Critical Factor

Copper, mg/L

3.0

200

pH 7.5, Alkalinity 250 (DIC =63)

180 CCWD EBMUD

160

µg Cu/8 hours

3.5

2.5 2.0 1.5

140 120 100 80 60 40

1.0

20

0.5 0.0 1940

0 80

1950

1960

1970

1980

1990

Service Line Installation Schock, M. R.; Sandvig, A. M. Jour. AWWA 2009, 101 (7), 71-82.

2000

70

60

50

40

30

20

10

0

Plumbing Age (years) Schock, M. R.; Lytle, D. A.; Clement, J. A. Effect of pH, DIC, Orthophosphate and Sulfate on Drinking Water Cuprosolvency, EPA/600/R-95/085, 1995.

• Since the middle 1990s, dozens of international research papers have been published showing the same phenomenon in diverse laboratory and field studies. • But only in certain water qualities will copper release be near or above the MCLG/AL from the time of installation.

38

DIC = 65 mg C/L Sytem, LCR Monitoring Continually Decreasing 90th Percentile Over Time 5 Cu Sites All Sites

Copper, mg/L

4

90th %

3

Action Level

2 1 0 9 ll 1

Fa

4 3 1 0 7 1 93 00 00 00 00 99 00 2 2 2 2 2 1 y ll ll ll ll ll Fa Fa Fa Fa Fa Ma

Schock, M. R.; Sandvig, A. M. Long-Term Impacts of Orthophosphate Treatment on Copper Levels. Jour. AWWA 2009, 101 (7), 71-82.

39

Effect of Orthophosphate and pH on Cu Solubility 10 0 mg PO4/L 3 mg PO4/L

Soluble Copper, mg/L

2 mg PO4/L 1 mg PO4/L

(23oC, 10 mg C/L)

1.3 mg/L

1

6.0

6.5

7.5

7.0

8.0

8.5

pH Lytle, D. A.; Schock, M.; Leo, J. The Impact of Orthophosphate on Copper Solubility, Proc. AWWA Annual Conference, Denver, CO, June 9-13, 2013.

40

Inhibition of Malachite Deposit: High DIC DIC = 50 mg C/L, PO4= 3.0 mg/L (upper pipes)

pH 8.0

pH 7.0

• Note the prevention of the aged malachite film when the orthophosphate is present. • You need enough orthophosphate to quickly get and stay below the MCLG

41

Consistency of Cu with PO4 (Indian Hill, OH) 1.8 1.6

3-3.3 mg/L dosing

1.4 1.2 1.0 0.8 0.6 0.4 0.2 0.0

19 9 19 0 9 19 1 9 19 2 9 19 3 9 19 4 9 19 5 9 19 6 9 19 7 9 19 8 9 20 9 0 20 0 0 20 1 0 20 2 0 20 3 04

th

90 Percentile Cu mg/L

High DIC (63 mg C/L) Water

Year

Schock, M. R.; Sandvig, A. M. Long-Term Impacts of Orthophosphate Treatment on Copper Levels. Jour. AWWA 2009, 101 (7), 71-82.

42

Effect of Phosphate Type and Concentration • Orthophosphate has been shown to immediately prevent Cu > MCLG in high alkalinities (over 200 to over 350 mg/L) on new pipe in lab and field studies if dosed at 3.3-3.5 mg/L as PO4 • Blended phosphates have rarely been shown to reduce Cu below MCLG at high alkalinities, but they have been shown to perpetuate Cu above the AL • Polyphosphates have not been successful unless DIC/pH combination would have worked anyway • Phosphates have been shown to be beneficial to prevent pitting in both low and high alkalinities • Even orthophosphate at low dosages and low DIC retards or prevents aging, but Cu release not an issue in DW. • For systems without LSLs, Pb is usually reduced below the AL at lower phosphate dosages than Cu. So, Pb control should not be the basis for exemptions from Cu treatment.

43

Lead and Copper Treatment Summary

44

Examples of Processes that can Undermine CCT • Softening processes • Tight membrane processes • Optimum or enhanced coagulation – Changes in type of coagulant – Changes in coagulant dosage

• Polyphosphate sequestration • Major changes to pH, Ca, Alkalinity • Changes in levels of oxidants through introducing disinfection (GWR) • Anion exchange treatment that can affect bicarbonate concentration and pH

45

Some Frequent Situations to Watch with Treatment Changes • Small system with multiple contaminants (U, As, Rn) using anion-exchange • Disinfection with high ammonia groundwater • Addition of oxygen or chlorine to high alkalinity ground water with low natural ORP • Replacing lime softening with IX softening • Overdosing of polyphosphate to prevent post-deposition of calcium carbonate • pH reductions to “maximize” IX or sorptive media run lengths or bed lifetimes 46

WQ Factors Affecting Metal Release • Temperature

• • • • • • • • • •

pH & stability (buffering) ORP/corrosion potential Type and amount of disinfectant Dissolved oxygen Alkalinity/DIC Orthophosphate Polyphosphate (amount and type) Chloride Sulfate Sorptive surfaces downstream of LSLs (ie. galvanized interior pipe)

• • • • • • • • • •

Iron (deposition and corrosion) Calcium Manganese Aluminum NOM (type, amount) Amount of mixing of WTPs or sources Ammonia Hydrogen Sulfide Silica Microbial activity (nitrification and other)

47

To Predict Change: Back to Basics • Look for changes in pH, DIC, orthophosphate, ORP – – – – –

Adsorb/desorb trace metals Destabilize Fe, Mn, Pb(IV) scales Impact valence state and solubility of Cu, Pb and other metals pH changes impacting inorganic removal or TTHM formation Adding oxidants for inorganics removal changing metal solubility

• Alum carry over/post deposition (Ca, Mn, Fe) consumes inhibitor, reacts with silicate and Mg in the water (may or may not be good) • Optimize treatment at the plant so that phosphate cannot react with Al, Ca, Fe, Mn, etc. to form turbidity/discolored water • Prevent DS scaling reactions if oversaturated with Al or Ca solids • Avoid adding complexing agents that enhance Cu, Pb solubility • Avoid anions that affect release rates and galvanic corrosion

48

OCCT/Lead Control Pilot Studies • PWS must conduct a proper study to look at what is going on in their pipes for their specific water quality zones in DS • Optimize under the current operating conditions • New studies needed well in advance of future treatment or operational changes that could impact lead or copper release. • New studies needed to anticipate other DS metal or radionuclied release side effects • This is SAME as use of jar tests for coagulation, column tests for filter media evaluation, column tests for As removal, pilot tests for ozonation or UV, etc. 49

System-Wide Optimization Essential Tool for Simultaneous Compliance • Requires addressing all direct and indirect factors causing metal release from the plant through the distribution system. • Requires treating and solving source of conflict, rather than Band-Aid on symptoms, e.g. – DBP precursor removal vs. chloramination – Iron/Manganese removal vs. sequestration – Operational issues, such as waste discharge constraints

• Anticipate and plan for secondary impacts or synergisms of process additions or changes 50

Simultaneous Compliance IS Possible • Recognition of diverse DS WQ relationships • Recognition of DS and premise plumbing materials • Commitment to address sources of chemical conflicts, e.g. – Removal of interfering substances to metal release – DBP precursors – Lead sources (notably LSLs)

• Holistic design and integration of processes • Homogenization of WQ across zones in system to extent possible • Resources to take actions necessary for O&M of plants and DS • Necessity of pilot studies to tailor to conditions 51

SAMPLING to Identify Pb Sources

52

Characteristics of Cu and Pb Sources • Few sources of Cu, and they are generally more uniform • When present, LSL is biggest reservoir of Pb, but may not always be highest peak value • Pb sources within housing and buildings – Numerous hidden locations (behind walls, under floors, etc.) – Small lateral extent in each occurrence – May be located considerably distance from consumption tap

• Sampling instruction details matter – Water use prohibited from tap – Water use prohibited from house/feed line

53

Typical Household Pb Sources

54

More Example Real Configurations

•Shut-off valves frequently are captured in 250 mL to 1 L samples. •Often not certified ANSI/NSF Section 9 55 55

Tool: Sample Volumes Representing Plumbing Wide-mouth bottles preferable to allow higher flow rate

After: Schock, M. R.; Lytle, D. A. Internal Corrosion and Deposition Control; In Water Quality and Treatment: A Handbook of Community Water Supplies; Sixth ed. 2011. 56

Identifying Pb Sources

Other pipe branches

First 1 L ends here

57

57

Sample Volume/Length for Cu Nominal Size

Material Type Copper tube Copper tube Copper tube Copper tube Copper tube Copper tube Copper tube Copper tube Copper tube

K L M K L M K L M

(in) 0.500 0.500 0.500 0.750 0.750 0.750 1.000 1.000 1.000

Thick OD ness ID ft per m per (in) (in) (in) mL/ft mL/m L L 0.625 0.625 0.625 0.875 0.875 0.875 1.125 1.125 1.125

0.049 0.04 0.028 0.065 0.045 0.032 0.065 0.05 0.035

0.527 0.545 0.569 0.745 0.785 0.811 0.995 1.025 1.055

43 46 50 86 95 102 153 162 172

141 151 164 281 312 333 502 532 564

23.3 21.8 20.0 11.7 10.5 9.8 6.5 6.2 5.8

7.1 6.6 6.1 3.6 3.2 3.0 2.0 1.9 1.8

58 58

Sample Volume/Length (other) Material

Type

Galvanized steel Sched 40 Galvanized steel Sched 40 Galvanized steel Sched 40

Lead Lead Lead PVC, CPVC PVC, CPVC PVC, CPVC HDPE

0.25-in wall 0.25-in wall 0.25-in wall Sched 80 Sched 80 Sched 80 200 psi

Nominal Thickness Size (in) OD (in) (in) ID (in)

ft per m per mL/ft mL/m L L

0.500 0.750 1.000

0.840 1.050 1.315

0.109 0.113 0.133

0.622 0.824 1.049

60 105 170

196 344 558

16.7 9.5 5.9

5.1 2.9 1.8

0.500

1.000

0.25

0.500

39

127

25.9

7.9

0.625

1.125

0.25

0.625

60

198

16.6

5.1

0.750

1.250

0.25

0.750

87

285

11.5

3.5

0.500 0.75 1

0.84 1.05 1.315

0.147 0.154 0.179

0.546 0.742 0.957

46 85 141

151 279 464

21.7 11.8 7.1

6.6 3.6 2.2

1

1.315

0.146

1.023

162

530

6.2

1.9

59 59

Resolution Depends on Dispersion

Dispersion reduced at higher sampling flow rates

From: VanDer Leer et. al. Applied Mathematical Modelling, (2002) 26:681–699

60

Including Cu, Zn and Fe is very Useful

61

Effect of Renovation (New Cu) at Sink

62

Copper Stagnation Profiles can Increase for Days LCR Guidance 6-16h

1

mg Cu/L

Theoretical stagnation curve, similar to LCR assumptions

Some experimental data for copper represents slow oxidation rate, surplus of oxidant, barrrier film

0.1

LCR Guidance

0.01

0

10

20

30

40

50

Time, Hours

60

70 63

Potential Constraints of Sequential Sampling • The farther the deviation from plug flow, the less accurate in finding exact location of specific sources • The longer the distance of the tap from the source, and the more bends, the more mixing that will take place – Lowering peak Pb – Loss in resolution – May displace precise peak positions relative to source locations

• Samples can be biased by water passing through leaded devices on the way to the bottle • Accurately capturing particulate release highly depends on on-off protocol, flow rate and flow turbulence 64

Acknowledgments • • • •

Darren Lytle, USEPA Stephanie Miller, UC MS student intern Michael DeSantis, ORISE Miguel Del Toral, USEPA Region 5

Disclaimer This presentation has been reviewed in accordance with U.S. Environmental Protection Agency (EPA) policy and approved for external presentation. The views expressed are those of the author[s] and do not necessarily represent the views or policies of EPA. 65 65

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Past webinar recordings available on ASDWA’s website: http://www.asdwa.org/index.cfm?fuseaction=Page.viewPage&pageId=509&parentID=503&nodeID=1