DISTRIBUTION SYSTEM WATER QUALITY CONTROL DEMONSTRATION · DISTRIBUTION SYSTEM WATER QUALITY CONTROL ... Rules of interpreting a Shewhart Control Chart ... Use all water system and

DISTRIBUTION SYSTEM WATER QUALITY CONTROL DEMONSTRATION

W A T E R R E S E A R C H F O U N D A T I O N P R O J E C T 4 2 8 6

PROJECT TEAM

Abigail Cantor, P.E., Chemical Engineer; Process Research Solutions, LLC; Madison, WI

Eric Kiefer, Manager; North Shore Water Commission; Glendale, WI

Kevin Little, PhD, Statistician, Informing Ecological Design, LLC; Madison, WI

Andrew Jacque, P.E., PhD, Environmental Engineer; University of Wisconsin-Platteville

Archie Degnan, Microbiologist; WI State Laboratory of Hygiene; Madison, WI

Barry Maynard, PhD, Geologist; University of Cincinnati

David Mast, PhD, Physicist; University of Cincinnati

Judith Cantor, Industrial Engineering Student; Acer Enterprises, Inc.; Raleigh, NC

Project Advisory Committee:

Frank Blaha, Project Manager; Water Research Foundation; Denver, CO

Andrew Reid, P.E.; AECOM; Concord, MA

Anne Spiesman, P.E.; Washington Aqueduct; Washington, D.C.

PROJECT FUNDING

Tailored Collaboration with funding split between:

North Shore Water Commission of Glendale, WI

Water Research Foundation of Denver, CO

THE NEED FOR ENHANCED CONTROL OF WATER QUALITY IN WATER SYSTEMS

There are multiple opportunities, yet unrealized in many drinking water systems, to improve water quality and to save money in doing so.

3 WAYS TO MORE EFFECTIVELY USE MONITORING INFORMATION

1. Be Comprehensive

2. Be Consumer-centric

3. Be Proactive in Water Quality Control and Improvement

3 TOOLS FOR PROCESS CONTROL

1. A Comprehensive Monitoring Strategy

2. A Standardized Monitoring Station for Tracking the Quality of Water at the Consumers’ Taps

3. A Display Tool That Quickly Makes Sense of Complicated Data, Allowing Us to be Proactive

BENEFITS

• A lower possibility of falling out of compliance with drinking water regulations (including the Lead and Copper Rule)

• A lower frequency of consumer complaints

• A documented decision-making process leading to higher consumer confidence produces and giving confidence to managers and water commissioners

• More consistent water quality

WATER SYSTEMN O R T H S H O R E W A T E R C O M M I S S I O N O F G L E N D A L E , W I

NORTH SHORE WATER COMMISSION

Photo courtesy of North Shore Water Commission

TREATMENT PROCESSES

Lake Michigan Water:

Potassium permanganateAlum and polymerActivated carbonFlocculation/sedimentationAnthracite carbon, sand and gravel filtersUV disinfectionFluorideOrthophosphateSodium hypochloriteStorage in a reservoirAmmonium hydroxide

Diagram courtesy of North Shore Water Commission

PREVIOUS USE OF TECHNIQUES AT NSWC

Before Disinfection and PO4 Change

After Disinfection and PO4 Change

TOOL #1: STRATEGY OF MONITORING

WHAT IS WATER QUALITY?

Pipe wall

Scales and films on Pipe Wall• Corrosion by-products• Biofilms• Precipitated chemicals from

• Source water contaminants• Chemical addition for water treatment

Water: Dissolved and entrained forms of pipe wall scales and films

COMPREHENSIVE MONITORING

• Parameters that describe the water “type” (This influences corrosion by-products formed and environmental conditions in the pipe.)

• Parameters that define the biostability of water, i.e. ability of microorganisms to grow in the water

• Parameters that track water treatment chemical addition

• Parameters that track source water and pipeline contaminants and debris

• Parameters that track metals released from piping material to the water

TOOL #2: CAPTURE OF WATER QUALITY EXPERIENCED BY THE CONSUMER

STANDARDIZED MONITORING STATION• Similar to a AwwaRF Pipe Loop• Less expensive• More compact• Standardized configuration for

exposure of metal to water• Can study metal plate scales like

distribution system pipe• Open-source technology• Can purchase from a fabricator

instead of building it yourself• Can test any type of metal• Can test chemical addition

scenarios

Alternative: Use Pipe Loops

SIMILITUDE

Surface Area per foot of 1.5” ID pipe = 32Volume per foot of 1.5” ID pipe

Surface Area of 16 metal plates in test chamber= 32Volume of test chamber

Concentrations of metals in test chamber similar to those found in actual pipe of the pure metal.

For example, lead concentrations from a lead test chamber are similar to concentrations of lead that would be found in a lead water service line in the water system being tested.

TOOL #3: INTERPRETATION OF WATER SYSTEM DATA

SHEWHART CONTROL CHARTS

• Plot of data over time• Interplay with average• New definition to

variation of the data (sigma unit based on moving range)

• Interplay with +/- 1, 2, and 3 sigma units

• 3 sigma units = Upper and Lower Control Limits

+3 σ+2 σ

+1 σ

-1 σ-2 σ

-3 σ

SHEWHART CONTROL CHART RULES

+3 σ+2 σ

+1 σ

-1 σ-2 σ

-3 σ

Troubleshoot if:• Data fall outside the 3 sigma unit lines• At least 2 out of 3 successive values fall

on the same side of the average and are at least 2 sigma units from the average

• At least 4 out of 5 successive values fall on the same side of the average and are at least 1 sigma unit from the average

• 8 or more successive points fall on the same side of the average line

ADDITIONAL INFORMATION

ADDITIONAL INFORMATION

• Data from Previous Distribution System Monitoring Projects at NSWC and Other Systems

• Examination of Metal Plates from Monitoring Station

• Residential Sampling

• Lead and Copper Rule Sampling

• SCADA Data

• On-line Sensor Data

• Regulatory and Investigative Data (Disinfection and Turbidity at all Total Coliform Rule sampling sites)

RESULTS: QUICK UNDERSTANDING OF DATA WITH SHEWHART CONTROL CHARTS

CONTROL CHARTS AND MONITORING DATA

CONTROL CHARTS AND MONITORING DATA

E N T R Y P O I N T M O N I T O R I N G S T A T I O N L E A D R E L E A S E

H I G H W A T E R A G E M O N I T O R I N G S T A T I O N L E A D R E L E A S E

+3 σ

-3 σ

Average

RESULTS: WATER QUALITY EXPERIENCED BY THE CONSUMER CAPTURED

WATER QUALITY SAME BETWEEN MONITORING STATION AND RESIDENCES

WATER QUALITY SAME BETWEEN MONITORING STATION AND RESIDENCES

WATER QUALITY SAME BETWEEN MONITORING STATION AND RESIDENCES

WATER REACTIONS SAME BETWEEN MONITORING STATION AND RESIDENCES

RESULTS: COMPREHENSIVE, CONSUMER-CENTRIC PROCESS CONTROL DEMONSTRATED

CONCEPTS OF WATER SYSTEM PROCESS CONTROL

• There are many interrelated factors that create the existing water quality.

• Monitoring strategy should capture as many factors as possible based on knowledge, time, and budget.

• Must try to monitor the water that the consumer receives.

• Must relate the consumers’ water to the water from the source through the treatment through the distribution system.

• Must view the data in a quick and meaningful way.

• Don’t jump to conclusions about cause and effect: measure, observe, theorize, experiment, monitor.

• Iterate: Monitor, observe, theorize, experiment , monitor, …

• You’ll be surprised how the essence of the water system will reveal itself to you over time.

EXAMPLE: WHAT CAUSED THE LEAD INCREASE?

No change in lead at entry point Increase in lead at high water age location

Summer pattern seen in water produced and other characteristics

PO4 dose change coincided with summer pattern

EXAMPLE: WHAT CAUSED THE LEAD INCREASE?

Turbidity matches iron patternInteresting pattern of lower iron in summer

Summer pattern of higher water usage and characteristics brought higher dissolved lead and copper, higher aluminum, lower dissolved and particulate iron. Seems unlikely that a small change in PO4 dose could cause this.

GETTING STARTED WITH SHEWHART CONTROL CHARTS

SHEWHART CONTROL CHART FOR MONITORING DATA

Excel Spreadsheet

“Insert” Tab

Create Data Sheet for Control ChartCreate Control ChartHelp

CLICK ON “CREATE A DATA SHEET”

[Title]

[Results] in [Units]

Date Results

DATA SHEET FILLED IN

Example Control Chart

Measured Value, e.g. Chloride in mg/L

Date Results

6/22/11 39.0

Etc.

CLICK “CREATE A CONTROL CHART”

CLICK “HELP”

Rules of interpreting a Shewhart Control Chart are summarized.

GETTING STARTED WITH A COMPREHENSIVE CONSUMER-CENTRIC PROCESS CONTROL METHODOLOGY

GET STARTED RIGHT AWAY

1. Graph disinfection data from Total Coliform Rule sampling sites. (For each site, create a graph of disinfection over time.)

2. Study the charts, understand past trends per site, and take action where disinfection is low currently.

If you just continue to do this, your water quality at the consumers’ taps will improve.

IF YOU WANT TO DO MORE

1. Take turbidity reading s at Total Coliform Rule sites, and graph and study that data. Take action where turbidity is high.

2. Now, turn your disinfection and turbidity data graphs into Shewhart Control Charts using the Excel add-in.

3. Graph any water system data you can get your hands on with a Shewhart Control Chart, study to determine the normal events and the unusual events, take action when data are out of a desired range.

IF YOU WANT TO DO EVEN MORE

1. Use a standardized monitoring station (or pipe loop) of lead, copper, brass, iron, or any metal of interest to track the status of metal transfer into the water routinely

2. Use a standardized monitoring station to track the ability of microorganisms to grow in the water and on metal surfaces

3. Use all water system and monitoring data with control charts to: Observe, Theorize, Experiment or Make Improvements, Monitor…. ITERATE – it’s a way of life and a philosophy of water system operation!

SUMMARY OF BENEFITS

BENEFITS THAT HAVE ALREADY BEEN EXPERIENCED BY WATER SYSTEMS USING THESE TECHNIQUES• System Operation• Triggering the need to troubleshoot equipment or other system operations• Saving money on treatment chemicals• Minimizing temporary water quality degradation• Evaluating system operations routinely

• Lead and Copper Rule Issues• Study lead and copper release in the context of multiple influencing factors• Serve as a surrogate for residential sampling to know transfer status routinely• Aid in determining mechanisms of lead and copper transfer specific to system• Establish key water quality parameters relevant to lead or copper release• Monitor and control the key water quality parameters• Monitor and control system transitions (simultaneous compliance)• Determine need for corrosion control chemicals• Compare and select corrosion control chemicals

BENEFITS THAT HAVE ALREADY BEEN EXPERIENCED BY WATER SYSTEMS USING THESE TECHNIQUES• Beyond Lead and Copper Rule Issues• Assess and control biostability of water, aid in setting disinfection level, stay in

compliance with Total Coliform Rule• Assess cleanliness of pipeline and effects of water main flushing• Develop hypotheses for further research on a system level and a national level

• A Comprehensive Consumer-centric Process Control Methodology• Establish water quality control methods• Establish water system process improvement methods

QUESTIONS?

CONTACT:Abigail Cantor, P.E.Process Research Solutions, [email protected]

Photo courtesy of Process Research Solutions, LLC