kick-off meeting jan 31, 2018 - michigan...kick-off meeting jan 31, 2018 •introductions and roles...

KICK-OFF MEETING

JAN 31, 2018

• Introductions and Roles• Objectives and Overview of Pipe Rig Study• Review of Coupon CCT Study Results• Detail Test Plan and Schedule• Open Discussion on Expectations and

Participants• Break to Visit Pilot Set-Up• Required Resources and Flint Staff Assistance• Wrap/ Comments/ Next Steps

• December 2015: Flint began boosting O-P to meet an EPA WQP of O-P > 3.1

• pH was required > 7

• Chlorine residual has continually improved in the system

• November 2017: We completed coupon studies for CCT

• December 2017: DEQ issued new WQP Requirements

Parameter Target100 Percent

Range

pH (s.u.) 7.5 7.2 - 7.9

Orthophosphate

residual (mg/L)3.3 3.1 - 4.5

Parameter Target90 Percent

Range

100 Percent

Range

pH (s.u.) 7.5 7.3 - 7.8 7.2 - 7.9

Orthophosphate

residual (mg/L)3.6 3.3 - 4.0 3.2 - 4.5

Free chlorine

residual (mg/L)1.5 - 1.8 1.4 - 1.9 1.3 - 2.0

Note: All daily values must fall within 100% range, excluding 9 days of allowed non-compliance per 6 months

Distribution System (EWDM Sampling Stations)

Water Treatment Facility

1) EPA Sequential Database

2) MDEQ Sentinel Database

3) MDEQ Residential Database

4) To better understand how Pb changed at specific locations over time, a subset was created from only those sites with Pb samples collected during all seasons

• The next phase was prescribed by EPA and DEQ to conduct pipe studies using harvested lead pipes from the system

• EPA has required pipe studies to:

– Establish the proper O-P Dose

– Determine impacts of blending GCDC Water into the GLWA Water

• CCT strategy efficacy can be studied on actual pipe from distribution system. Orthophosphate dose comparison is possible. [1]

• Collection of stagnation samples is possible, depending on design. [2]

[1] Schock & Lytle, 2011[2] Cantor, Hill, & Giani, 2017

Welter , G., Schock, M., Miller, S., Razza , R., & Giammar, D. (2015, November 17)

Civardi & GrayEisnor & Gagnon, 2003

Madison Water Utility, 2016

• Assess lead concentration reduction in GLWA water from exhumed Flint LSLs with increased orthophosphate dose compared to current GLWA conditions.

• Study effect of pH increase (7.5) on lead concentration compared to current GLWA conditions.

• Recommend Final CCT for Flint and WQPs

COMPLETED NOV. 2017

2.0 mg/L PO4

2.5 mg/L PO4

3.0 mg/L PO4

3.5 mg/L PO4

4.0 mg/L PO4

5.0 mg/L PO4

Target pH: 7.2

2.0 mg/L PO4

2.5 mg/L PO4

3.0 mg/L PO4

3.5 mg/L PO4

4.0 mg/L PO4

5.0 mg/L PO4

Target pH: 7.5

2Replicates

2Replicates

• Conducted under zero headspace to eliminate pH atmospheric drift

• Lead Concentrations expressed in (µg/L-day)– The number of days between water changes

varies from 3-4 days (7 days if there is a holiday)

– µg/L-day charts express the normalized lead concentrations

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2.0 mg/L PO4, [1] 2.0 mg/L PO4, [2] 2.5 mg/L PO4, [1] 2.5 mg/L PO4, [2]



Steady State

• Outliers were removed using the interquartile range (IQR) function

• Replicate coupon data were averaged if data was determined not to be outlying

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2.0 mg/L PO4 2.5 mg/L PO4 3.0 mg/L PO4 3.5 mg/L PO4

4.0 mg/L PO4 5.0 mg/L PO4 Steady State

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2.0 mg/L PO4 2.5 mg/L PO4 3.0 mg/L PO4


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7.2 pH Target 7.5 pH Target

• Trends appear similar between target pH groups

• t-test used to determine if pH made a significant impact on lead solubility

• t-test assuming unequal variances

• Significance (α) value of 0.05

• Null hypothesis: lead concentrations are the same

• After two different t-tests, pH was determined to not to make a significant impact on lead concentrations

Comparison Mean 1 Mean 2T

Statistic

t Critical

(two tail)

Lead is the

same

2.0A vs 2.0B 17.85 16.91 0.2308 2.021 SUPPORTED

2.5A vs 2.5B 17.52 16.81 0.1762 2.024 SUPPORTED

3.0A vs 3.0B 13.83 13.10 0.2196 2.021 SUPPORTED

3.5A vs 3.5B 11.31 12.29 0.3232 2.018 SUPPORTED

4.0A vs 4.0B 11.04 9.43 0.5715 2.022 SUPPORTED

5.0A vs 5.0B 9.75 8.95 0.4337 2.021 SUPPORTED

Summarized t-Test 1 Results for pH Comparison (All Data)

Comparison Mean 1 Mean 2T

Statistic

t Critical

(two tail)

Lead is the

same

2.0A vs 2.0B 11.565 12.239 -0.924 2.074 SUPPORTED

2.5A vs 2.5B 10.870 13.660 -3.550 2.086 REJECTED

3.0A vs 3.0B 10.412 9.554 1.400 2.086 SUPPORTED

3.5A vs 3.5B 8.531 9.398 -1.656 2.093 SUPPORTED

4.0A vs 4.0B 8.166 7.238 1.658 2.074 SUPPORTED

5.0A vs 5.0B 8.482 6.939 2.832 2.080 REJECTED

Summarized t-Test 2 Results for pH Comparison (After Steady-State)

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Comparison Mean 1 Mean 2 T Statistict Critical

(two tail)Lead is the same

2.0 vs 2.5 11.902 11.864 0.060 2.074 SUPPORTED

2.5 vs 3.0 11.864 10.097 3.074 2.080 REJECTED

3.0 vs 3.5 10.097 8.964 2.377 2.074 REJECTED

3.5 vs 4.0 1.200 1.806 2.521 2.080 REJECTED

4.0 vs 5.0 1.806 1.965 0.274 2.074 SUPPORTED

Summarized t-Test 3 Results

• Third t-test used to determine significant differences between consecutive doses

• Results determined no significant difference between 2.0 and 2.5 mg/L as PO4, or 4.0 and 5.0 mg/L as PO4.

• Each point represents the average of one batch

• Bolded points represent the overall average lead concentration at each dose

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Orthophosphate Dose (mg/L as PO4)

• No significant difference in lead concentration at target pH values

• No significant difference in corrosion inhibitor performance below doses of 2.5 mg/L PO4, and above doses of 4.0 (3.5?) mg/L PO4

• Lead concentrations leveled off in the 3.5 to 4 range mg/L PO4.

• EPA constructed pipe rigs

• There are 4 rigs with 4 pipes each

• Pipes have been running since Spring 2016

• 4 pipes were harvested by EPA in Oct. 2017 and replaced

• We need to verify 4 replaced pipes are suitable to use—if so 16 pipes for use

• We have not received any pipe lead background data –starting fresh with data

• GLWA water currently enters the Flint WTP prior to Flint adding chemicals

• The pipes currently receive Flint treated water

• Pipes current CCT entering -----

Tap (WQP Adjusted Water Leaving)Tap (WQP Adjusted Water Leaving)

Sample ID Pipe IDPipe

InstallationTotal Lead (µg/L)

A-1 2300 Vernon St. 10/2/2017 5.5

A-2 2614-02 Existing 2.7

A-3 2614-03 Existing 4.3

A-4 2614-01 Existing 2.2

B-1 742-4 Existing 9.7

B-2 742-2 Existing ND

B-3 2317 Vernon St. 10/2/2017 3.8

B-4 742-03 Existing 2.4

C-1 2417 Vernon St. 10/2/2017 3.1

C-2 2301 ID #3 Existing 4.3



D-1 2402 Vernon St. 10/2/2017 4.4

D-2 749 ID #1 Existing 3.9



• Entering GLWA water will be routed to feed the pipes and the pipes will be switched from Flint water to straight GLWA

• GLWA CCT water quality entering Flint---

CSII (GLWA Water Entering)CSII (GLWA Water Entering)

• Phase 1– Test only GLWA water– Test different O-P levels to optimize lead and dose– Test above using pH as received– Some testing at set pH of 7.5

• Phase 2– Pick a few of O-P conditions and one pH– Blend in 5% GCDC—See impacts– Possibly Phase 1 refinement also

• Phase 3???– Nothing planned or scheduled-TBD

Input Water pH Condition Target pHOrthophosphate Dose

(mg/L as PO4)Replicate Pipes

GLWA As Received 7.2-7.4

1.2 (as received) 2

2.5 2

3.0 2

3.5 2

4.0 2

5.0 2

GLWA Adjusted 7.5

1.2 (as received) 1

2.5 1

3.0 1

4.0 1

Number of Pipes 16

Orthophosphate

Dose (mg/L as PO4)

Replicate

Pipes

1.2 (as received) 2

2.5 2

Rig #Orthophosphate Dose

(mg/L as PO4)

Replicate

Pipes

23.0 2

3.5 2

34.0 2

5.0 2

pHOrthophosphate Dose

(mg/L as PO4)Pipes

7.5

1.2 (as received) 1

2.5 1

3.0 1

4.0 1

• 8 of 16 Pipes retained for Phase 1 refinements• Orthophosphate doses for blended conditions could be adjusted

based on Phase 1 findings

Input WaterpH

ConditionTarget pH

Orthophosphate Dose

(mg/L as PO4)Number of Pipes

95% GLWA

5% GCDC

(COUNTY)

TBD TBD

1.2 (as received) 2

2.5 2

3.0 2

4.0 2

Phase 1 Refinement TBD 8

• Hopefully and assumed that pipes are at steady state. Initially recommended 12 month study for Phase 1 and 2

• Budget constraints cut testing to 9 months and then to 8 months which is current plan

• We all need to recognize we have no control over time required for pipes to equilibrate so in a sense schedule is arbitrary based on budget

• Plumb GLWA water to rigs with hose to switch sources. Reduce pressure to TBD.Keep on Flint water now

• Wire rig-mounted outlets into timer to control pumps

• Assist in plumbing-in pH control system

• Provide work desk/space

• Need Internet access

• Perhaps printing and copying occasionally

• Plant access

• Provide orthophosphate and caustic

• Provide Operator to assist with chemical make-up, sampling etc.

• Check and make up chemicals as needed on weekends

kick-off meeting jan 31, 2018 - michigan...kick-off meeting jan 31, 2018 •introductions and roles...

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