1. Project #4586: Optimization of Phosphorus-Based Corrosion Control Chemicals Using a Comprehensive Perspective of Water Quality
Principal Investigator:
Abigail F. Cantor, P.E.
Process Research Solutions, LLC
Madison, Wisconsin

2. Acknowledgements Water Research Foundation
Water Environment & Reuse Foundation
8 water utility entities (12 water systems)
State and Federal drinking water regulators
Wastewater Treatment Plant Personnel
Experts whose findings have been applied to Process Research Solutions’ investigative protocols
Please read the acknowledgements in the report.

3. What is the effectiveness of orthophosphate addition and pH/alkalinity adjustment in actual water systems?

4. Typical Drinking Water Pipe

5. Typical Composition of Drinking Water
Various chemical and microbiological components:
Naturally occurring organic carbon compounds
Naturally occurring microorganisms
Nitrogen compounds
Phosphorus compounds
Carbonate compounds
Hydroxide compounds
Hydrogen compounds
Sulfate compounds
Chloride compounds
Oxygen and oxygen compounds
Iron compounds
Manganese compounds
Other metals and minerals from the environment

6. Typical Interactions Between the Pipe Walls and the Drinking Water
Various chemical and microbiological components:
Naturally occurring organic carbon compounds
Naturally occurring microorganisms
Nitrogen compounds
Phosphorus compounds
Carbonate compounds
Hydroxide compounds
Hydrogen compounds
Sulfate compounds
Chloride compounds
Oxygen and oxygen compounds
Iron compounds
Manganese compounds
Other metals and minerals from the environment
See next diagram for a close up of pipe wall and drinking water interactions that shape water quality

7. The Shaping of Water Quality

8. Drinking Water Quality Problems That Can Occur and are Interrelated
Various chemical and microbiological components:
Naturally occurring organic carbon compounds
Naturally occurring microorganisms
Nitrogen compounds
Phosphorus compounds
Carbonate compounds
Hydroxide compounds
Hydrogen compounds
Sulfate compounds
Chloride compounds
Oxygen and oxygen compounds
Iron compounds
Manganese compounds
Other metals and minerals from the environment
Drinking water quality problems that can occur and are interrelated:
Lead release into water
Copper release into water
Iron release into water
Other metals release into water
Pathogenic microorganisms like E. Coli and Legionella
Non-pathogenic microorganisms
Disinfection by-product formation
Smells
Discolored water

9. A Comprehensive Perspective of Water Quality
Various chemical and microbiological components:
Naturally occurring organic carbon compounds
Naturally occurring microorganisms
Nitrogen compounds
Phosphorus compounds
Carbonate compounds
Hydroxide compounds
Hydrogen compounds
Sulfate compounds
Chloride compounds
Oxygen and oxygen compounds
Iron compounds
Manganese compounds
Other metals and minerals from the environment
Drinking water quality problems that can occur and are interrelated:
Lead release into water
Copper release into water
Iron release into water
Other metals release into water
Pathogenic microorganisms like E. Coli and Legionella
Non-pathogenic microorganisms
Disinfection by-product formation
Smells
Discolored water

10. Regulatory Perspective of Lead and Copper Release
Carbonate compounds
Lead
Copper

11. Regulatory Solution to Lowering Lead and Copper Release-Option A
Carbonate compounds
Less release of:
Lead
Copper

12. Regulatory Solution to Lowering Lead and Copper Release- Option B
Carbonate compounds
Less release of:
Lead
Copper

13. Comprehensive Solution to Lead and Copper Release and Interrelated Issues

14. Every Water System is on a Water Quality Continuum

15. PRS Monitoring Station
Testing Method:
PRS Monitoring Station
A water distribution system monitoring station that measures representative water quality that the consumer experiences.
Similar to a Water Research Foundation pipe loop; would get similar results as using a pipe loop
Many advantages to using the PRS Monitoring Station configuration:
Cost
Ease of use
Lower incidence of leaks
Uniform configuration and operation for comparisons of data
Easy analysis of scales on internal metal plates for important insights

16. PRS Monitoring Station Test Chambers
View of plates sitting inside open test chambers.

17. Results of System Hygiene Efforts- 90th Percentile LCR Compliance Data for Lead
Units = µg/L AL 15
Hygiene
Efforts
Begin

18. Results of System Hygiene Efforts-90th Percentile LCR Compliance Data for Copper
Units = µg/L AL
1300
Hygiene
Efforts
Begin

19. Varying Dominance of Metal Releasing Factors
PRS Monitoring Station Lead Test Chamber Data
High lead release, quickly dropping over time as carbonates and oxides form on metal surfaces
Particulate lead released by adsorption of existing lead compounds to entrained particulates of iron, manganese, and aluminum
Carbonate and oxide formation continues
Carbonates and oxides take on a lesser role as other factors become more significant. Here, two factors, nitrification cycles of lead release and particulate adsorption, were identified.

20. Categories of Factors Uniform Corrosion of Metals
Biostability of Water
Precipitation and Dissolution of Chemical Scales

21. Common Responses to the Comprehensive Perspective and Approach to Water Quality Control

22. “The comprehensive perspective cannot be applied to all water systems”: FALSE
It is orthophosphate addition and pH/alkalinity adjustment that should not be applied to all water systems.

23. Orthophosphate Did Not Correspond to Lower Metals Release
A = system
with PO4
= Ave. conc.
= Conc.
variation

24. Carbonate Concentration Did Not Correspond to Metals Release

25. “The comprehensive perspective cannot be applied to all water systems”: FALSE
It is orthophosphate addition and pH/alkalinity adjustment that should not be applied to all water systems.
Comprehensive perspective
More factors considered
Seeks for control of both dissolved and particulate metals as there are different factors for each form

26. Dissolved Lead Correlations in Each Water System
Parameter
Water System A B C D E F G H1 H2
Alkalinity - pH +
Chloride
Sulfate
Iron
Manganese
Aluminum
Nitrification
Ammonia
Nitrate
Dissolved Organic Carbon
Microbiological Population
Total Phosphorus
Orthophosphate
+ = trended together; - = trended inversely

27. Dissolved Copper Correlations in Each Water System
Parameter
Water System A B C D E F G H1 H2
Alkalinity - pH
Chloride
Sulfate +
Iron
Manganese
Aluminum
Nitrification
Ammonia
Nitrate
Dissolved Organic Carbon
Microbiological Population
Total Phosphorus
Orthophosphate
+ = trended together; - = trended inversely

28. Particulate Lead Correlations in Each Water System
Parameter
Water System A B C D E F G H1 H2
Alkalinity pH
Chloride
Sulfate
Iron +
Manganese
Aluminum
Nitrification
Ammonia
Nitrate
Dissolved Organic Carbon -
Microbiological Population
Total Phosphorus
Orthophosphate
+ = trended together; - = trended inversely

29. Particulate Copper Correlations in Each Water System
Parameter
Water System A B C D E F G H1 H2
Alkalinity pH
Chloride
Sulfate
Iron +
Manganese
Aluminum
Nitrification
Ammonia
Nitrate
Dissolved Organic Carbon -
Microbiological Population
Total Phosphorus
Orthophosphate
+ = trended together; - = trended inversely

30. “The comprehensive perspective cannot be applied to all water systems”: FALSE
It is orthophosphate addition and pH/alkalinity adjustment that should not be applied to all water systems.
Comprehensive perspective
More factors considered
Seeks for control of both dissolved and particulate metals as there are different factors for each form
Monitoring and data assessment should be a means of quality control and improvement of system operations

31. Monitoring and data assessment should be a means of quality control and improvement of system operations

32. “The comprehensive perspective cannot be applied to all water systems”: FALSE
It is orthophosphate addition and pH/alkalinity adjustment that should not be applied to all water systems.
Comprehensive perspective
More factors considered
Seeks for control of both dissolved and particulate metals as there are different factors for each form
Monitoring and data assessment should be a means of quality control and improvement of system operations
Cleaning and biostability attainment should be expected preventative maintenance of the system and infrastructure

34. “The comprehensive perspective cannot be applied to all water systems”: FALSE
It is orthophosphate addition and pH/alkalinity adjustment that should not be applied to all water systems.
Comprehensive perspective
More factors considered
Seeks for control of both dissolved and particulate metals as there are different factors for each form
Monitoring and data assessment should be a means of quality control and improvement of system operations
Cleaning and biostability attainment should be expected preventative maintenance of the system and infrastructure
Can’t lay down a passivating barrier on pipe walls until the walls are clean.

35. Pyromorphite (Intended Phosphate Compounds) Not Always Found on Metal Surfaces of PO4 Dosing Systems

36. Can’t lay down a passivating barrier on pipe walls until the walls are clean

37. “This is Voodoo Science”: FALSE
This is empirical science.
This graphic is on Wikipedia which is from a contributor, Gary Hammock, a mechanical engineer.

38. “Many water systems have used orthophosphate or pH/alkalinity adjustment successfully. That many cases can’t be wrong.”: FALSE
The pH/alkalinity adjustment or orthophosphate dosing is effective in specific water systems.

39. “Many water systems have used orthophosphate or pH/alkalinity adjustment successfully. That many cases can’t be wrong.”: FALSE
The pH/alkalinity adjustment or orthophosphate dosing is effective in specific water systems.
The influencing water quality parameters can play a role in both chemical and microbiological interactions and the true reason that adjustment of the specific water quality parameters is effective for lowering lead and copper release has not been identified.

40. “Many water systems have used orthophosphate or pH/alkalinity adjustment successfully. That many cases can’t be wrong.”: FALSE
The pH/alkalinity adjustment or orthophosphate dosing is effective in specific water systems.
The influencing water quality parameters can play a role in both chemical and microbiological interactions and the true reason that adjustment of the specific water quality parameters is effective for lowering lead and copper release has not been identified.
Other water system operations, such as carrying out a high velocity flushing program or reduction in system residence time or better elimination of nutrients or filter cleaning, are occurring simultaneously to the presumed corrosion control strategy and are actually the real influencing factors on corrosion control.

41. “Many water systems have used orthophosphate or pH/alkalinity adjustment successfully. That many cases can’t be wrong.”: FALSE
The pH/alkalinity adjustment or orthophosphate dosing is effective in specific water systems.
The influencing water quality parameters can play a role in both chemical and microbiological interactions and the true reason that adjustment of the specific water quality parameters is effective for lowering lead and copper release has not been identified.
Other water system operations, such as carrying out a high velocity flushing program or reduction in system residence time or better elimination of nutrients or filter cleaning, are occurring simultaneously to the presumed corrosion control strategy and are actually the real influencing factors on corrosion control.
Follow up sampling of the outcome of the corrosion control strategy is inadequate and not representative of the actual effectiveness.

42. “Many water systems have used orthophosphate or pH/alkalinity adjustment successfully. That many cases can’t be wrong.”: FALSE
In summary, it is difficult to uncover the true influencing factors on lead and copper release in a given system if comprehensive water quality parameters are not tracked and representative lead and copper release samples are not obtained and studied along with the water quality parameters.

43. Example 1 of Complicated Logic Uncovered with Comprehensive Method

44. Example 2 of Complicated Logic Uncovered with Comprehensive Method

45. “Microorganisms only cause localized corrosion and it only shows up in particulate form.”: FALSE
There are many types of microorganisms and many metabolic pathways by which they contribute to metals corrosion in drinking water.
Microbiologically influenced corrosion (MIC)is systemic as the chemicals produced by microorganisms increase and can be measured in the system water.
Both dissolved and particulate metals can be produced by MIC depending on the significant metabolic pathways at work and the types of microorganisms involved.

46. Examples of MIC in this Project
Water Systems A and B
Systemic production of nitrates by microorganisms synchronized with systemic increase in organic carbon trending with dissolved lead release
Water System F and E
Pinhole leaks in copper pipe creating particulate copper
Pinholes were localized under sections of biofilms
However, pinholes were throughout the complete water system because the available and unavailable nutrients in the system environment were the same throughout

47. “This report disputes some of the NDWAC recommendations and EPA proposals for LCR revisions.”: TRUE
Solubility models for lead don’t reflect reality
Solubility models for copper don’t reflect reality
Must deal with dissolved metals separately from particulate metal
Orthophosphate and pH/alkalinity adjustment are not relevant to all
Even when they are relevant, they don’t guarantee protection for the consumer
4586 recommendations can be used for the framework for an LCR and a distribution system water quality rule. Example, monitoring turbidity and disinfection concentrations in a water system routinely are key.

48. Lead and Copper Release Control in Drinking Water – Water System Hygiene
Routinely Improve Infrastructure
Removal of Lead and Galvanized Iron Service Lines
Water Main Replacement
Routine Uni-directional Flushing of Water Mains
Other cleaning – filters, storage tanks, etc.
Biostability Improvement
Source water
Filters and Wells !!!
Tanks
Distribution system
(continued)

49. Lead and Copper Release Control in Drinking Water
Do not use solubility model for lead or copper
Ongoing “desktop study” of water system stats
Routine turbidity and disinfection concentration tracking in distribution system
Study of problematic buildings
Routinely gauge lead and copper release
Consider orthophosphate in specific cases
Do not assume complete protection
Must perform cleaning and biostability in order for ortho to work properly
Do not use polyphosphate
Use adequate dosage
Need environmental impact analysis of phosphorus on WWTP and environment

50. The Fate of Orthophosphate after the Drinking Water System

51. Phosphorus Removal at Wastewater Treatment Plants
Chemical precipitation
Typical up to about 90% phosphorus removal
Results in costs of additional chemical and costs of handling and disposing of additional sludge
Biological removal
For higher % phosphorus removal
Requires larger wastewater tank for larger anaerobic zone and more energy
Combination
For the highest % phosphorus removal with optimized operations and costs

52. Information Needed for Municipal PO4 Impact Assessment
WWTP Parameters
Influent wastewater flow
Influent phosphorus mass
Effluent wastewater flow
Effluent phosphorus mass
Phosphorus mass removal
% phosphorus removal
$/pound iron for phosphorus removal
Pounds iron per pound phosphorus removed
Current phosphorus discharge limit
Future phosphorus discharge limit
Drinking Water Parameters
Drinking water pumpage
Dosage of orthophosphate used and confirmed with measurement
% polyphosphate in orthophosphate product used
Estimates
How much of the drinking water arrives at WWTP?
% of drinking water pumpage used for landscaping
% of drinking water pumpage used for cooling water
Infiltration and inflow into wastewater system

53. Wastewater Treatment Plant Chemical Cost Calculations
% current influent wastewater phosphorus mass that is from municipal phosphate addition
% future influent wastewater phosphorus mass that is from municipal phosphate addition if dosage or product changed
Cost of additional chemical usage
Whether current and future phosphorus discharge limits are met under current and future conditions

54. Wastewater Treatment Plant Other Cost Calculations Needed
Wastewater tank volume changes
Sludge storage tank volume changes
Labor
Energy use
Sludge storage operations
Sludge processing operations
Sludge disposal operations

55. Be careful stating orthophosphate dosing
Drinking water measurements typically in field and can only measure orthophosphate concentration
Measurements are stated as mg/L as PO4
Wastewater personnel use total phosphorus coming into plant in units of mg/L as P
Because of the presence of polyphosphate in many drinking water products, TP > PO4
Sometimes other polyphosphate and total phosphorus are used with units of mg/L as PO4

56. To Keep Dosing and Units Clear:
State the component that was measured
Orthophosphate
Polyphosphate
Total phosphorus
State the units of the measurement
mg/L as PO4
mg/L as P
Convert components to the same units for calculations but continue to state component and units clearly

57. Polyphosphate Impacts of WWTP
Polyphosphate does not add to corrosion control in drinking water
Polyphosphate adds to the total phosphorus that the wastewater treatment plant receives and the costs of removal
Get more corrosion control bang for your buck by eliminating polyphosphate from the corrosion control product
See Utility C

58. Summary of WWTP Impacts of Phosphate Dosing
Depends on:
Drinking water pumpage – landscaping use – cooling water use versus influent wastewater flow
Efficiency of phosphorus removal at WWTP
Stringency of phosphorus limits

59. Factor for Environmental and Socio-economic Costs for Triple Bottom Line
Phosphorus also in landscaping water and cooling water going directly to natural bodies of water.
Use the phosphorus discharge limit set by the state agency
Environmental impact in the natural body of water
Community use of the natural body of water

60. More details in the final report for project #4586
More details in the final report for project # Many nuances of drinking water systems and wastewater treatment plants…
Read the executive summary
Read the conclusions
Read the recommendations
For more details or to carry out the recommendations, read the individual relevant chapters

61. This report challenged common understandings of lead and copper corrosion control. The goal of the project was not to tear down institutional concepts, but to build up a larger perspective: to look at lead and copper release more comprehensively, to treat the problems and not the symptoms, and to add more tools to the toolbox.

62. Questions?

63. Thank you Comments or questions, please contact: jcuppett@waterrf.org
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