permit fact sheet general information - dnr.wi.gov · 01/12/2010 · the plant is fueled by natural...

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Permit Fact Sheet General Information Permit Number: WI-0000931-06-0

Permittee Name: WE - Valley Power Plant

Address: 231 West Michigan Street

PO Box 2046

City/State/Zip: Milwaukee WI 53201-2046

Discharge Location: South Menomonee Canal

Receiving Water: Menomonee River

StreamFlow (Q7,10): Zero (intake volume exceeds stream flow, and the river may have countercurrent flow)

Stream Classification:

Warmwater sport fish community, non-public water supply

Facility Description Valley Power Plant is a cogeneration facility that generates electricity for the grid and steam for a downtown district heating system. The plant is fueled by natural gas, recently converted from a coal-fired plant. Built in 1968 to 1969, the power plant consists of two units, each with two boilers and a single steam turbine generator rated at 140 megawatts, for a total power plant capacity of 280 megawatts. It is designed to operate year-round as an intermediate-load plant, but the output of steam and electricity may vary daily and seasonally based on demand. Valley Power converted from coal to natural gas in two phases. Construction on the Unit 1 conversion started in April 2014 and completed in November 2014. Construction on the Unit 2 conversion started in November 2014 and completed in November 2015. The facility no longer has any coal operations. Remaining coal from the coal pile was excavated and removed from the site. The area was filled with clean fill, recycled concrete (crushed stone aggregate) and fines from the zoo interchange project. Coal-related wastewater streams, such as ash handling-related water, are no longer generated. The removal of the coal pile also eliminated the coal pile runoff that had been treated by the on-site wastewater treatment system with the process wastewaters.

Following the fuel conversion project, We Energies began rerouting all process wastewater to MMSD in 2016. Process wastewater sources include demineralizer regeneration waste, demineralizer resin brine cleaning waste, boiler blowdown, yard runoff, floor washing, steam leaks, equipment drainage, equipment cooling leaks, contact cooling water, and reverse osmosis (RO) reject. The remaining wastewater at the facility is primarily once through cooling water from dual pass condensers, which discharge into the South Menomonee Canal of the Menomonee River and some site storm water. There is a separate outfall for each unit. The annual average wastewater flow is 107.5 million gallons per day. Non-contact cooling water is the majority of the discharge to the South Menominee Canal; heat addition from the condenser cooling water is the principal pollutant.

Sample Point Designation

Sample Point Number

Discharge Flow, Units, and Averaging Period

Sample Point Location, WasteType/sample Contents and Treatment Description (as applicable)

601 52.1 MGD Unit 1 Menomonee River water intake monitoring for background

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Sample Point Designation

Sample Point Number

Discharge Flow, Units, and Averaging Period

Sample Point Location, WasteType/sample Contents and Treatment Description (as applicable)

3 yr Avg water quality.

602 54.4 MGD 3 yr Avg

Unit 2 Menomonee River water intake monitoring for background water quality.

701 N/A

Menomonee River water intake structures for unit 1 and unit 2 condenser cooling water.

702 Emergency Intake Unit 1

703 Emergency Intake Unit 2

001 52.0 MGD 3 yr Avg

Unit 1 condenser cooling water, some site storm water discharges, and occasional Demineralizer Water Tank discharge to the South Menomonee Canal.

002 54.5 MGD 3 yr Avg

Unit 2 condenser cooling water discharge to the South Menomonee Canal.

003

0.29 MGD 3 yr Avg

Unit 1 alternative outfall which recirculates heated effluent from Outfall 001 back into the water intake. This outfall is used to prevent icing of the water intake structure in the winter, for zebra mussel control with thermal treatments, and backwashing the cylindrical wedge-wire screens to flush out any plugging that may occur from biofouling or debris.

004

0.62 MGD 3 yr Avg

Unit 2 alternative outfall which recirculates heated effluent from Outfall 002 back into the water intake. This outfall is used to prevent icing of the water intake structure in the winter, for zebra mussel control with thermal treatments, and backwashing the cylindrical wedge-wire screens to flush out any plugging that may occur from biofouling or debris.

603 325 MBTU/hr 3 yr Avg

The heat discharged from Outfalls 001 and 002 shall be limited on a combined basis. This sampling point accounts for the total heat.

1 Influent – Cooling Water Intake Structure - Proposed Monitoring

Sample Point Number: 601- UNIT 1 WATER INTAKE; 602- UNIT 2 WATER INTAKE Monitoring Requirements and Limitations

Parameter Limit Type Limit and Units

Sample Frequency

Sample Type

Notes

Flow Rate MGD Daily Total Daily

Temperature Maximum

deg F Daily Continuous

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Monitoring Requirements and Limitations


Sample Frequency

Sample Type

Notes

Temperature Average deg F Daily Continuous

Changes from Previous Permit: The location of these sample points in the permit has been moved from the Surface Water section to the Influent section to more accurately describe their physical location and to avoid any confusion. No changes in monitoring have occurred from the previous permit.

The BTA determination based on the 2014 316(b) federal regulations was added.

Explanation of Limits and Monitoring Requirements The intake temperature is used for calculating the amount of heat discharged using the change in temperature between the intake and the outfall, or ∆T.

Best Technology Available (BTA) Evaluation

See attachment for BTA Justification.

Sample Point Number: 701- Water Intake See Attachment: Evaluation of the Cooling Water Intake Structures (CWIS) for Valley Power Plant (VAPP) for Reissuance WPDES Permit WI-0000931-06-0.

Sample Point Number: 702- Emergency Intake Unit 1 and 703- Emergency Intake Unit 2



Sample Frequency

Sample Type

Notes

Flow Rate MGD Daily Continuous

Changes from Previous Permit: Emergency Intake 702 has been split into two sampling points, 702 and 703, to better represent that there are two emergency intakes.

Best Technology Available (BTA) Evaluation

The emergency cooling water intakes are considered to be BTA because due to their limited use, their environmental impacts are minimized.

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2 Surface Water - Proposed Monitoring and Limitations

Sample Point Number: 001- UNIT 1 CONDENSER COOLING WATER; 002- UNIT 2 CONDENSER COOLING WATER



Sample Frequency

Sample Type

Notes

Flow Rate MGD Daily Total Daily

Temperature Maximum

Daily Max 120 deg F Daily Continuous

Temperature Average deg F Daily Continuous

Heat MBTU/hr Daily Calculated See Temperature Limitations Section Below

pH Field Daily Max 9.0 su Quarterly Grab

pH Field Daily Min 6.0 su Quarterly Grab

Chlorine, Total Residual

Daily Max 19 ug/L Daily Grab See Total Residual Chlorine Section Below


Monthly Avg 7.3 ug/L Daily Grab See Total Residual Chlorine Section Below


Weekly Avg 7.3 ug/L Daily Grab See Total Residual Chlorine Section Below

Changes from Previous Permit The daily maximum limit for Total Residual Chlorine has changed from 38 µg/L to 19 µg/L.

A monthly average limit for Total Residual Chlorine of 7.3 μg/L has been added.

Monitoring for pH has been reduced from quarterly to weekly.

Explanation of Limits and Monitoring Requirements Refer to the attached memo dated November 7, 2017. The water quality based effluent limits for total residual chlorine apply to the discharge, with an acute limit of 19 µg/L. The chronic limit of 7.3 µg/L is also included because there is no dilution with the river (effluent flow exceeds the flow in the Menomonee River). Previously, daily maximum effluent limits based on the acute toxicity criterion were set equal to 2 × ATC except in cases where a zone of initial dilution had been demonstrated. Updates to this procedure in ch. NR 106, Wis. Adm. Code now require consideration of available dilution. The 1-Q10 flow (estimated as 80% of the 7-Q10 flow) is now used to calculate daily maximum limits in a mass balance equation similar to the other averaging periods such as weekly or monthly averages. In cases where the 1-Q10

flow is equal to 0 cfs, the WQBEL is now equal to the actual water quality criteria. Therefore, a daily maximum effluent limitation has been set to 19 μg/L. This value is equal to the criteria of 19.03 μg/L, but expressed to two significant figures. The typical use of chlorine used to prevent biofouling consists of the addition of 12.5% liquid sodium hypochlorite 30 to 45 minutes per day (time duration and number of days per week varies seasonally), followed by dechlorination with sodium bisulfite prior to discharging. Since dechlorination is used, a test result <100 µg/L is considered to be in compliance with the water quality based effluent limit in accordance with Standard Requirement 5.3.8 of the draft permit (recognizes the level of detection for chlorine is greater than the limit). For this reason it’s also

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impractical to include a mass limit for chlorine, so it’s exempt from a mass limit in accordance with s. NR 106.07(2), Wis. Adm. Code. Revisions to ch. NR 106 and 205, Wis. Adm. Code align Wisconsin’s water quality-based effluent limitations with 40 CFR 122.45(d) which requires that industrial permits contain both daily maximum and monthly average effluent limitations, wherever limitations are determined necessary to protect water quality. Because the existing weekly average limit of 7.3 μg/L (7.28, expressed to two significant figures) is still applicable and represents a shorter averaging period, the monthly average effluent limit is set to be equal to the 7.3 μg/L concentration as well.

Discharges that are a source of heat, such as a power plant’s condenser cooling water, are subject to temperature limits to protect aquatic life. The effluent temperature is being monitored, but the discharge is subject to a limit related to the heat output from the power plant measured in millions of BTUs (British thermal units) per hour, as an alternative effluent limit to regulate temperature. Refer to Sampling Point 603 where the heat limit is included for the combined discharges from both Outfall 001 and 002. Included in the permit is the standard prohibition on the discharge of PCBs in 3.2.2.9, which is applicable to power plants. PCBs may be in the oil contained in older electrical transformers (manufactured before PCBs were banned). Because the Valley Power Plant has electrical equipment containing oil and PCBs in quantities that could be harmful, it’s subject to the EPA Spill Prevention, Control and Countermeasures regulations in 40 CFR Part 112. Regular inspections of electrical equipment are conducted to check for signs of leakage, and any repairs or cleanups are addressed. The Valley Power Plant has not had any reportable spills based on a review of records the past 11 years. There is an extremely low risk of PCB discharges at the Valley Power Plant because of how the equipment is constructed, monitored, and the oil is not routinely filled or emptied. We Energies has either replaced oil filled electrical equipment that contained PCBs or the oil has been replaced with non-PCB oil.

Sample Point Number: 003- UNIT 1 ALTERNATIVE OUTFALL; 004- UNIT 2 ALTERNATIVE OUTFALL



Sample Frequency

Sample Type

Notes

Flow Rate MGD Daily Total Daily Estimated Volume

Changes from Previous Permit No changes from the previous permit.

Explanation of Limits and Monitoring Requirements Alternative Outfalls 003 and 004 return heated effluent from Outfalls 001 and 002 to their corresponding water intake structures on the Menomonee River. Use of the alternative outfalls occurs for three purposes – (1) de-icing of the water intake during the winter, (2) backwashing the wedge-wire screens to flush out any plugging that may occur from biofouling or debris, and (3) for thermal treatments to kill zebra and quagga mussels. Monitoring is required for estimated total daily flow to track when the outfalls are used. No other monitoring is necessary since the effluent quality is the same as Outfall 001 and 002. Deicing typically occurs 57 times a year at a return flow rate of 5.5 MGD.

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Sample Point Number: 603- HEAT DISCHARGED Monitoring Requirements and Limitations


Sample Frequency

Sample Type

Notes

Heat Daily Avg 1,450 MBTU/hr

Daily Calculated

Changes from Previous Permit No changes from previous permit

Explanation of Limits and Monitoring Requirements See Attachment of AEL Approval Letter for details

3 Compliance Schedules

3.1 Temperature AEL The alternative effluent limit (AEL) for temperature approved in this permit may be renewed in subsequent permit reissuances. An AEL renewal request must be supported with justification in the next permit application. To renew the AEL complete the thermal study update actions below.

Required Action Due Date

Submit Proposal for Thermal Study Update: The permittee shall submit to the department for approval a work plan to update the thermal study. The follow-up study shall be performed to update the June 2017 Request for Alternative Effluent Limitation to verify the permitted heat load limit for the power plant's condenser cooling water discharge ensure the protection and propagation of a balanced indigenous population of shellfish, fish and wildlife.

The work plan shall include at the minimum the following:

a. Biological sampling within the Menomonee Canal and Burnham Canal

b. Evaluate the extent of a zone of passage for the Burnham Canal and upper reach of the South Menomonee Canal with the Burnham Canal Wetland.

c. Evaluate a variable heat load where heat loading is reduced during the months of March and April and how this may affect the zone of passage in the mixing zone area.

Items b and c only need to be completed if construction of the Burnham Canal Wetland project starts.

06/01/2019

Submit AEL Request: The permitee shall submit the thermal study update report with the WPDES reissuance application.

01/01/2023

Explanation of Compliance Schedules See Attachment of AEL Approval Letter for details

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Special Reporting Requirements None.

Other Comments: None.

Attachments: Substantial Compliance Determination

Water Flow Schematic(s)

Map(s)

Water Quality Based Effluent Limits

Water Quality Based Effluent Limits - 2011

Public Notice

Evaluation of the Cooling Water Intake Structures (CWIS) for Valley Power Plant (VAPP) for Reissuance WPDES Permit WI-0000931-06-0

AEL Memo

Discharge Data

Proposed Expiration Date: 6/30/2023

Prepared By:

Emma Lorenzen Wastewater Engineer

Date: 5/18/2018

cc: Geisa Theilan - DNR

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Discharge Data for Valley Power

Outfall 001

Average Max Temperature (F)Month 2013 2014 2015 2016 2017 Average January 59.2 65.5 62.5 63.6 61.7 62.5 February 58.6 71.5 74.2 63.1 64.4 66.3 March 59.8 66.2 70.3 65.5 58.7 64.1 April 63.2 67.2 65.3 62.7 65.6 64.8 May 70.4 78.6 76.3 75.9 61.4 72.5 June 73.4 80.5 83.5 88.4 72.1 79.6 July 81.0 78.9 85.8 84.5 91.4 84.3 August 87.4 78.6 83.2 91.8 87.4 85.7 September 81.7 67.8 81.1 - 83.5 78.5 October 69.7 73.7 69.5 - 71.9 71.2 November 59.1 65.1 68.2 50.6 54.9 59.6 December 62.8 63.1 71.6 56.9 50.4 61.0 Annual 68.9 71.4 74.3 70.0 69.0 70.7

Days OperatedMonth 2013 2014 2015 2016 2017 Average January 31 31 31 31 31 31.0 February 28 28 28 29 28 28.2 March 31 31 31 14 31 27.6 April 30 30 30 30 30 30.0 May 31 30 31 31 1 24.8 June 30 30 30 30 6 25.2 July 31 31 31 31 31 31.0 August 31 31 31 5 31 25.8 September 30 30 30 0 30 24.0 October 31 31 30 0 24 23.2 November 30 30 30 10 30 26.0 December 31 31 31 31 31 31.0 Annual 365 364 364 242 304 327.8

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Average Flow (MGD)

Month 2013 2014 2015 2016 2017 Average

January 49.5 38.6 41.0 37.7 65.9 46.5

February 39.1 39.3 42.1 42.3 62.6 45.1

March 45.8 41.8 56.7 60.4 76.9 49.7

April 65.8 47.4 79.5 79.2 79.1 70.2

May 45.3 51.6 78.7 79.2 0.6 50.8

June 43.5 0.1 79.4 65.1 6.8 43.8

July 79.4 0.2 79.4 53.6 68.0 51.2

August 79.3 78.7 11.8 - 73.3 48.2

September 79.3 5.5 70.2 - 74.7 45.9

October 79.3 78.7 11.8 - 53.4 44.6

November 77.1 64.0 79.3 47.4 82.5 63.7

December 45.8 47.7 47.7 85.7 72.7 59.9

Annual 54.3 39.3 62.2 65.0 59.7 51.6

Heat Discharged (BTU/hr)

Month 2013 2014 2015 2016 2017 Average

January 209.8 255.2 187.5 178.0 273.1 220.7

February 216.8 298.4 195.5 162.6 224.5 219.6

March 224.1 263.4 209.3 253.3 233.0 208.8

April 220.8 244.6 182.6 220.6 195.1 212.7

May 174.3 157.8 193.8 263.5 - 196.1

June 174.3 157.8 193.8 263.5 - 151.2

July 123.8 0.0 207.7 166.6 212.4 142.1

August 210.7 0.0 204.5 131.1 195.9 126.4

September 206.4 0.0 199.7 - 214.7 155.2

October 175.4 143.0 29.0 - 105.6 113.0

November 172.4 214.3 230.4 214.5 155.0 168.7

December 217.7 170.4 220.8 252.2 109.0 194.0

Annual 183.3 157.1 189.1 208.1 159.5 165.1

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Outfall 002

Average Max Temperature (F)

Month 2013 2014 2015 2016 2017 Average

January 65.5 66.0 74.2 59.4 67.9 66.6

February 64.9 71.7 80.6 52.0 66.5 67.1

March 65.4 69.0 81.7 60.8 76.9 70.8

April 67.4 65.4 83.9 50.9 66.3 68.6

May 73.1 78.2 - 73.0 76.3 75.1

June 82.3 86.9 - 85.5 85.9 85.1

July 87.7 86.8 69.7 86.1 86.2 83.3

August 86.8 91.0 78.3 91.0 - 86.8

September - 85.6 80.6 84.4 73.1 80.9

October 78.1 73.4 74.2 74.0 77.4 75.4

November 75.9 69.7 62.5 64.9 - 68.2

December 68.3 65.0 50.8 61.6 45.9 58.3

Annual 72.8 76.0 73.2 71.0 70.7 72.8

Days Operated

Month 2013 2014 2015 2016 2017 Average

January 31 31 31 31 31 31.0

February 28 28 28 29 28 28.2

March 31 31 31 31 9 26.6

April 30 9 11 19 20 17.8

May 22 31 0 27 31 22.2

June 30 17 0 30 30 21.4

July 30 31 4 31 10 21.2

August 7 31 31 31 0 20.0

September 0 30 30 30 24 22.8

October 10 31 31 31 23 25.2

November 30 29 30 30 0 23.8

December 31 31 31 31 31 31.0

Annual 280 330 258 351 237 291.2

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Average Flow (MGD)

Month 2013 2014 2015 2016 2017 Average

January 48.8 38.6 41.5 53.8 48.9 46.3

February 40.7 37.3 43.0 54.8 51.4 45.5

March 46.3 40.4 64.1 75.5 15.8 48.4

April 60.8 71.4 74.6 63.3 34.7 36.9

May 71.2 69.1 - 63.9 80.9 51.2

June 79.2 74.7 - 78.9 79.9 56.1

July 76.1 79.2 65.0 73.9 22.5 51.5

August 71.9 79.2 65.6 86.1 0.0 49.4

September - 79.0 65.6 86.1 35.5 53.3

October 40.3 79.2 86.1 86.1 53.5 63.6

November 44.2 58.6 86.0 86.1 0.0 54.6

December 52.3 48.5 72.2 76.2 49.9 59.8

Annual 57.1 62.1 66.1 74.2 39.3 51.4

Heat Discharged (BTU/hr)

Month 2013 2014 2015 2016 2017 Average

January 233.4 274.4 302.0 201.1 275.1 257.2

February 254.5 285.1 403.8 133.9 272.4 269.9

March 249.0 261.3 528.9 221.0 80.9 268.2

April 270.8 213.3 654.5 30.1 64.4 133.9

May 272.4 238.1 - 94.0 251.3 194.2

June 188.2 304.0 - 193.5 239.5 198.4

July 224.8 251.4 0.0 194.2 62.7 181.4

August 182.0 268.3 5.9 276.7 - 148.0

September - 277.8 200.2 240.4 32.8 187.8

October 225.0 217.1 222.0 254.3 148.1 182.8

November 265.9 255.0 123.8 325.5 - 240.5

December 229.1 216.0 55.3 269.5 44.6 162.9

Annual 240.0 255.5 243.3 210.0 121.8 183.8

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Intake 601


Month 2013 2014 2015 2016 2017 Average

January 41.8 42.2 43.3 47.5 41.8 43.3

February 40.2 46.7 48.4 44.4 45.4 45.0

March 40.9 42.2 49.9 45.6 43.5 44.4

April 49.4 50.2 55.0 52.6 54.4 52.3

May 59.4 66.9 64.4 64.0 48.0 60.6

June - 71.0 70.3 74.9 72.2 72.1

July 76.5 - 71.7 74.3 75.4 74.5

August 74.9 - 69.3 78.6 74.3 74.3

September 72.4 68.0 68.4 - 70.3 69.8

October 60.4 60.4 58.8 - 62.2 60.4

November 49.7 48.5 52.8 48.5 45.0 48.9

December 42.4 44.9 44.8 43.0 40.3 43.1

Annual 64.4 56.5 67.2 65.6 55.5 55.3

Days Operated

Month 2013 2014 2015 2016 2017 Average

January 31 31 31 31 31 31.0

February 28 28 28 29 28 28.2

March 31 31 31 14 31 27.6

April 30 28 30 30 30 29.6

May 14 21 31 31 1 19.6

June 0 24 30 30 6 18.0

July 18 0 31 31 31 22.2

August 31 0 31 5 31 19.6

September 30 3 28 0 30 18.2

October 31 31 5 0 24 18.2

November 30 30 30 10 30 26.0

December 31 30 31 31 31 30.8

Annual 305 257 337 242 304 289.0

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Average Flow (MGD)

Month 2013 2014 2015 2016 2017 Average

January 53.9 42.6 42.2 41.4 70.0 50.0

February 41.6 42.4 42.6 42.7 63.3 46.5

March 46.1 43.5 56.4 61.4 79.5 50.6

April 66.2 50.6 79.2 79.2 79.1 70.2

May 75.6 73.4 78.5 79.2 0.6 48.4

June - 72.3 79.2 74.8 7.1 43.8

July 74.6 - 79.2 65.1 68.0 51.1

August 79.2 - 79.2 53.6 73.3 48.1

September 79.2 53.3 75.0 - 74.7 45.8

October 79.2 78.5 70.1 - 53.4 44.5

November 76.8 63.7 79.0 47.4 82.5 63.6

December 45.5 49.0 47.7 85.7 76.0 60.5

Annual 54.3 51.8 58.0 56.7 60.6 51.9

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Intake 602


Month 2013 2014 2015 2016 2017 Average

January 43.4 41.8 45.1 41.2 42.4 42.8

February 41.7 46.6 48.1 39.1 45.0 44.1

March 43.6 43.6 53.1 47.8 45.9 46.8

April 49.2 56.4 60.6 49.6 60.4 54.8

May 63.8 64.8 - 68.0 62.1 64.7

June 71.9 73.2 - 74.7 72.3 73.0

July 76.4 73.9 67.3 75.6 75.7 73.8

August 77.8 77.0 70.1 77.2 - 75.5

September - 69.4 69.3 72.5 71.1 70.6

October 55.9 61.8 63.1 62.3 66.1 61.8

November 51.2 50.7 54.3 52.8 - 52.2

December 44.6 46.4 45.1 45.3 41.9 44.6

Annual 57.7 63.0 66.4 74.2 57.3 57.1

Days Operated

Month 2013 2014 2015 2016 2017 Average

January 31 31 31 31 31 31.0

February 28 28 28 29 28 28.2

March 31 31 31 31 9 26.6

April 30 9 8 19 20 17.8

May 22 31 0 27 31 22.2

June 30 17 0 30 30 21.4

July 31 31 4 31 10 21.2

August 7 31 31 31 0 20.0

September 0 30 30 30 24 22.8

October 10 31 31 31 23 25.2

November 30 29 30 30 0 23.8

December 31 31 31 31 31 31.0

Annual 281 330 255 351 237 291.2

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Average Flow (MGD)

Month 2013 2014 2015 2016 2017 Average

January 53.4 42.8 43.0 53.8 51.8 49.0

February 41.8 41.3 43.0 54.8 51.8 46.6

March 47.6 42.7 65.0 75.5 15.8 49.3

April 60.8 71.4 79.2 63.3 34.7 35.6

May 71.2 69.1 - 63.9 80.9 51.2

June 79.2 74.7 - 78.9 79.9 56.1

July 73.7 79.2 65.0 73.9 22.5 51.5

August 71.9 79.2 65.6 86.1 0.0 49.4

September - 79.0 65.6 86.1 35.5 53.3

October 40.3 79.2 86.1 86.1 53.5 63.6

November 44.2 58.6 86.0 86.1 0.0 54.6

December 52.3 48.5 72.2 76.2 51.5 60.1

Annual 54.3 58.5 56.4 59.1 39.8 51.7

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Combined Outfall 603

Average Heat Discharged (BTU/hr)

Month 2013 2014 2015 2016 2017 Average

January 443.2 529.6 489.5 379.1 548.2 477.9

February 471.3 583.5 599.8 296.5 496.9 489.6

March 473.1 524.6 738.2 335.4 313.9 477.0

April 491.6 308.6 428.0 239.7 259.4 345.5

May 367.6 390.8 193.8 345.4 251.3 309.8

June 235.6 324.1 205.1 393.8 239.5 279.6

July 341.3 251.4 207.7 360.8 275.1 287.2

August 251.8 268.3 210.4 297.9 195.9 244.9

September 206.4 277.8 399.9 240.4 247.5 274.4

October 248.0 360.1 250.1 254.3 253.8 273.2

November 438.3 460.8 354.3 397.0 155.0 361.1

December 446.8 386.4 276.1 521.7 153.6 356.9

Annual 367.3 387.7 361.0 339.0 281.4 347.3

DATE: November 7, 2017 FILE REF: 3200 TO: Emma Lorenzen – WY/3 FROM: Nick Lent – SER/Milwaukee SUBJECT: Water Quality-Based Effluent Limitations for Wisconsin Electric Power Co. Valley Power Plant WPDES Permit No. WI-0000931-06-0 (FID 241007800) This is in response to your request for an evaluation of the need for water quality-based effluent limitations (WQBELs) using Chapters NR 102, 104, 105, 106, 207, 210 and 217 of the Wisconsin Administrative Code (where applicable), for the discharge from Wisconsin Electric Power Co. - Valley Power Plant in Milwaukee County. This discharge is located in the Menomonee River Watershed in the Milwaukee River Basin. The evaluation of the permit recommendations is discussed in more detail in the attached report. Based on our review, the following recommendations are made for both outfalls on a chemical-specific basis: Outfall 001 & Outfall 002: Condenser Cooling Water

Parameter Hourly Maximum

Daily Maximum

Daily Minimum

Weekly Average

Monthly Average

Footnotes

Flow Rate 1

Chlorine Residual 19 μg/L 7.3 μg/L 7.3 μg/L 2

pH field 9.0 s.u. 6.0 s.u.

Temperature – Maximum Temperature – Average Heat

1450 MBTU/hr (both outfalls)

120° F 3

Footnotes: 1. Monitoring only. 2. The 7.3 ug/L monthly average limit is required per s. NR 106.07(4)(e)1, Wis. Adm. Code 3. The current permit includes this alternative effluent limitation for temperature of 1450 MBTU/hr.

This limit was approved in previous documentation for this facility, and no recommendation is provided in this memo as to whether or not the limit should be changed for permit reissuance. This decision is at the discretion of the permit drafter and biologists review.

Along with the chemical-specific recommendations mentioned above, the need for acute and chronic whole effluent toxicity (WET) monitoring and limits has also been evaluated for the discharge from We Energies. Following the guidance provided in the Department's November 1, 2016 Whole Effluent Toxicity Program Guidance Document - Revision #11, no acute or chronic WET tests are recommended for permit reissuance.

Please consult the attached report for details regarding the above recommendations. If there are any questions or comments, please contact Nick Lent at (414) 263-8623 or [email protected] Attachments:

1. WQBEL memo – Wisconsin Electric Power Co. Valley Power Plant 2. Site Map – Wisconsin Electric Power Co. Valley Power Plant

State of WisconsinCORRESPONDENCE/MEMORANDUM

PREPARED BY: Nick Lent – Wastewater Engineer, Effluent Limits Calculator E-cc: Geisa Thielen – WPDES Permit Compliance Staff Diane Figiel – Water Quality-Based Effluent Limits Coordinator Kari Fleming – Biomonitoring Coordinator

Attachment # 1

Page 1 of 11

Wisconsin Electric Power Co. Valley Power Plant – WQBEL Memo

Water Quality-Based Effluent Limitations for Wisconsin Electric Power Co. Valley Power Plant

WPDES Permit No. WI-0000931-06-0 FID 241007800

Prepared by: Nick Lent

PART 1 – BACKGROUND INFORMATION

Facility Description: Valley Power Plant is located at 1035 W Canal St. in Milwaukee, WI between the Menomonee River and South Menomonee Canal. The plant was originally constructed in the late 1960’s and was recently converted from coal to natural gas combustion. The plant generates electricity for the grid and steam for over 400 customers in a 1.8 mi2 area. The plant consists of two units, each with two boilers and a single steam turbine generator rated at 136 megawatts, for a total power plant capacity of 272 megawatts. It is designed to operate year-round as an intermediate-load plant, but the output of steam and electricity may vary daily and seasonally based on demand. The conversion from coal to natural gas was completed in two phases. The Unit 1 conversion was completed in November 2014 and the Unit 2 conversion was completed in November 2015. Remaining coal from the coal pile was excavated and removed from the site. The area was filled with clean fill, recycled concrete (crushed stone aggregate) and available fines. The removal of the coal pile eliminated the coal pile runoff and ash handling-related wastewater that had been treated by the on-site treatment system. Therefore, following the fuel conversion project, Wisconsin Electric Power Co. (doing business as “We Energies”) submitted a Notice of Intent (NOI) to discharge all it’s remaining process wastewaters to the Milwaukee Metropolitan Sewerage District (MMSD). MMSD issued an approval letter in October 2015. Starting in January 2016, Valley Power Plant began rerouting all process wastewater to MMSD. These process wastewater sources include demineralizer regeneration waste, demineralizer resin brine cleaning waste, boiler blowdown, yard runoff, floor washing, steam leaks, equipment drainage, equipment cooling leaks, contact cooling water, and reverse osmosis (RO) reject. Since all of this is sent to the MMSD collection system, outfall 005 is no longer in use. The only remaining surface water discharge at the facility is once through cooling water from dual pass condensers at outfall 001 and 002 which discharge to the South Menomonee Canal, which is contiguous with the Menomonee River. Discharge Description: Water is drawn from the Menomonee River through two 316(b)-compliant intake structures (usually only one unit at a time), and is used as condenser cooling water to convert the exhaust steam from the turbines back into water for reuse. Heat addition is the main pollutant in the condenser cooling water discharge. Sodium hypochlorite is used as needed near the intake structure for mussel control, and sodium bisulfite is used for dechlorination before discharge. Considering the recently simplified processes; heat addition is the principal pollutant in the condenser cooling water discharge. Changes since the current permit issuance: None. The current permit was modified effective September 1, 2017 from the previous version because there is no longer any form of wastewater discharge besides noncontact cooling water at outfall 001 and 002. Outfall 005 has been discontinued. Limits and monitoring for ammonia nitrogen, total phosphorus, and mercury were removed because 100 % of the discharge is from the receiving water, and temperature is the main pollutant.

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Existing Permit Limitations: The current permit, which was modified in Fall 2016 and expires on 12/31/2017, includes the following effluent monitoring and limitations for the surface water discharge(s): For both Outfall 001 and Outfall 002: Condenser Cooling Water

Parameter Hourly Maximum

Daily Maximum

Daily Minimum

Weekly Average

Footnotes

Flow Rate 1 Chlorine Residual 38 ug/L 7.3 ug/L pH field 9.0 s.u. 6.0 s.u. Temperature – Maximum Temperature – Average Heat

- -

1450 MBTU/hr (@ SP 603: combined

001 and 002)

- -

- -

- -

2

Footnotes: 1. Monitoring only. 2. An alternative effluent limit for temperature has been approved in previous documentation for

this facility. The current permit requires continuous maximum and average temperature data collection, as well as reporting that the combined heat output is < 1450 MBTU/hr. The limit represents the maximum total heat addition from both generating units, on a year-round basis, to ensure protection and propagation of a balanced indigenous population of shellfish, fish, and wildlife. Because the heat limit applies to the combined discharge from outfalls 001 and 002, sampling point 603 was created to account for the combined discharge.

The existing permit also includes once annual acute and chronic whole effluent toxicity (WET) testing. These requirements are revisited in Part 6 of this attachment. Receiving Water Information: Name: South Menomonee Canal, adjacent to the Menomonee River Outfall location: 001 is located at 43°1'42.4 "N 87°55'29.64"W and outfall 002 is located at

43°1'42.4 "N 87°55'22.8"W Classification: Warm Water Sport Fish, non-public water supply. (Coldwater and Public Water

Supply criteria would be used for bioaccumulating compounds of concern, because the discharge is within the Great Lakes basin.)

Flows: 7-Q10 = 0 cubic feet per second (cfs) 7-Q2 = 0 cfs

Harmonic Mean Flow = 0 cfs Hardness = ~ 350 mg/L as CaCO3, but not needed based upon available effluent characterization. % of flow used to calculate limits: N/A Multiple dischargers: There are no other significant discharges to surface water within immediate area Impaired water status: Referencing the approved 2016 303(d) impaired waters listing, neither the

South Menomonee Canal (WBIC 3000043) or Burnham Canal (WBIC 3000042) are specifically listed for any surface water impairments on the 303(d) list. However, at the point where the Burnham Canal meets the Menomonee River (approximately 2,500 feet downstream) segment 1 of the Menomonee River (mile 0 – 3) is listed for the following conditions:

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Start Mile

End Mile

Pollutant Source Category

Impairment Date Listed

TMDL Creation Priority

0 3 Fecal Coliform PS/NPS Recreational Restrictions 4/1/2010 Low0 3 PCBs Contam. Sed. Contaminated Fish Tissue 4/1/1998 High0 3 E. coli PS/NPS Recreational Restrictions 4/1/1998 Low0 3 Unspecified Metals Contam. Sed. Chronic Aquatic Toxicity 4/1/1998 Low0 3 Total Phosphorus PS/NPS Low DO 4/1/1998 Low

Note: the draft 2018 assessments of the Burnham Canal indicate impairment from excessive chloride.

Effluent Information: Flow rate(s): (as reported in the 2017 permit application)

Outfall 001 Outfall 002Peak annual average 62.05 MGD 71.37 MGDPeak daily 86.11 MGD 86.11 MGDPeak weekly 86.11 MGD 86.11 MGDPeak monthly 86.11 MGD 86.11 MGD

Note – the annual average flow rate is typically used in to calculate the WQBELs, however with no receiving water flow for dilution, the resulting concentration limits are equal to criteria regardless of effluent flow rate. Typically, only one unit is in operation at a time, and both units are exercised frequently (there is no significant difference between one unit or the other). As a result, the average flow is similar for each unit (~ 61 MGD for both outfall 001 and 002 from January 2013 – July 2017).

Water source: The facility has two 316(b) compliant intakes located on the Menomonee River, just north of the power plant. All process wastewater streams have been eliminated or routed to the MMSD collection system for treatment.

Hardness = ~ 350 mg/L as CaCO3, but not needed based upon available effluent characterization. Acute dilution factor used: Not applicable – there is no approved Zone of Initial Dilution (ZID). Effluent characterization: Because the facility no longer discharges any process wastewater, and the

discharge is solely noncontact (condenser) cooling water, the permit application did not require the full priority pollutant scan. Outfalls 001 and 002 are substantially identical wastewater therefore data was only provided for outfall 002. This data is considered to be representative of both outfalls and was used to determine the need for limits for both.

Additives: Sodium hypochlorite is used intermittently near the intake structure for mussel control and eradication. Sodium bisulfite is used to remove the chlorine prior to discharge.

PART 2 – WATER QUALITY-BASED EFFLUENT LIMITATIONS FOR TOXIC SUBSTANCES – EXCEPT AMMONIA NITROGEN

The following tables list the water quality-based effluent limitations for this discharge along with the results of effluent sampling for all of the detected substances. All concentrations are expressed in terms of micrograms per Liter (μg/L), except for chloride (mg/L). Aluminum, iron, magnesium and sulfate were also detected in the effluent however criteria or secondary values are not available for these substances.

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Daily Maximum Limits based on Acute Toxicity Criteria (ATC): RECEIVING WATER FLOW = 0 cfs (100% of 1-Q10, which is estimated as 80% of 7-Q10)

ATC or MAX. 1/5 OF MEAN 1-day MEAN Secondary EFFL. EFFL. EFFL. MAX. INFL. CONC. SUBSTANCE Value* LIMIT LIMIT CONC. CONC. (Menomonee River)

Chlorine 19.03 19.03 3.81 <100Chloride 757 1514 302.8 201 201 196

Barium* 3077.3 3077.3 615.5 54.4 54.4 54.6

Boron* 17625 17625 3525 46.3 46.3 47.5

Manganese* 1682.68 1682.68 336.54 50.5 50.5 48.5

*Criteria unavailable in ch. NR 105, Wis. Adm. Code for this substance, limits calculated using secondary values. Weekly Average Limits based on Chronic Toxicity Criteria (CTC): RECEIVING WATER FLOW = 0 cfs (¼ of the 7-Q10)

CTC or WEEKLY 1/5 OF MEAN MEAN Secondary AVE. EFFL. EFFL. INFL. CONC. SUBSTANCE Value* LIMIT LIMIT CONC. (Menomonee River)

Chlorine 7.28 7.28 1.46 <100

Chloride 395 395 79 201 196

Barium* 170.96 170.96 34.19 54.5 54.6 Boron* 979 979 195.8 46.3 47.5 Manganese* 93.48 93.48 18.70 50.5 48.5

*Criteria unavailable in ch. NR 105, Wis. Adm. Code for this substance, limits calculated using secondary values. Conclusions and Recommendations: Chlorine: Because chlorine is used near the intake structure for mussel control, effluent limitations for chlorine are necessary to protect the discharge from causing or contributing to an exceedance of the applicable water quality criteria in the receiving water. Several small changes are needed from the existing effluent limitations to comply with updated portions of ch. NR 106 and 205, Wis. Adm. Code. The first change is related to the specified daily maximum limit. Previously, daily maximum effluent limits based on the acute toxicity criterion were set equal to 2 × ATC except in cases where a zone of initial dilution had been demonstrated. Updates to this procedure in ch. NR 106, Wis. Adm. Code now require consideration of available dilution. The 1-Q10 flow (estimated as 80% of the 7-Q10 flow) is now used to calculate daily maximum limits in a mass balance equation similar to the other averaging periods such as weekly or monthly averages. In cases where the 1-Q10 flow is equal to 0 cfs, the WQBEL is now equal to the actual water quality criteria. Therefore, a daily maximum effluent limitation of 19 μg/L is recommended for permit reissuance. This value is equal to the criteria of 19.03 μg/L, but expressed to two significant figures. The second change is related to updates concerning effluent limit expression requirements. Revisions to ch. NR 106 and 205, Wis. Adm. Code align Wisconsin’s water quality-based effluent limitations with 40 CFR 122.45(d) which requires that industrial permits contain both daily maximum and monthly average effluent limitations, wherever limitations are determined necessary to protect water quality. Because the

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existing weekly average limit of 7.3 μg/L (7.28, expressed to two significant figures) is still applicable and represents a shorter averaging period, the monthly average effluent limit is recommended to be set equal to the 7.3 μg/L concentration as well for permit reissuance. Note that these WQBELs are well below the currently achievable limits of detection and quantification of readily available in-field testing kits. Test methods for total residual chlorine, approved in ch. NR 219 - Table B, Wis. Adm. Code, normally achieve a limit of detection of about 20 to 50 μg/L and a limit of quantitation of about 100 μg/L.

Criteria for compliance with WQBELs in this general situation from ch. NR 106.07(6), Wis. Adm. Code says:

(a) Compliance with the concentration limit shall be determined as follows: (1) When the water quality based effluent limit is less than the limit of detection, effluent levels

less than the limit of detection are in compliance with the effluent limitation. (2) When the water quality based effluent limit is less than the limit of detection, effluent levels

greater than the limit of detection, but less than the limit of quantification are in compliance with the effluent limitation except when analytically confirmed and statistically confirmed by a sufficient number of analyses of multiple samples and use of appropriate statistical techniques.

Note: All 739 chlorine results from both outfall 001 and 002 were reported as non detect. Chloride: The one effluent result of 201 mg/L provided in the permit application for outfall 002 is greater than 1/5 of the weekly average limit (which would typically mean that an effluent limitation is needed per s. NR 106.05(6), Wis. Adm. Code). However, the permit application also included a sample result for chloride from the intake, which indicates that the effluent discharge concentration is directly attributable to the source water. These results are expected given that the discharge originates from the Menomonee River. Therefore, no effluent limit or monitoring for chloride is recommended for permit reissuance. This determination is consistent with those provided in the 2005 and 2011 WQBEL memos for this facility. Manganese: The one effluent result of 50.5 μg/L provided in the permit application for outfall 002 is greater than 1/5 of the weekly average limit (based on the secondary value). However, the permit application also included a sample result for manganese from the intake, which indicates that the effluent discharge concentration is directly attributable to the source water. These results are expected given that the discharge originates from the Menomonee River. Therefore, no effluent limit or monitoring for Manganese is recommended for permit reissuance. There are no other toxic substances where available effluent data from Valley Power Plant is above a level of concern for the discharge to the South Menomonee Canal.

PART 3 – WATER QUALITY-BASED EFFLUENT LIMITATIONS FOR AMMONIA NITROGEN

The permit application did not include any sample results for ammonia nitrogen, however a significant amount of effluent data was collected during WPDES Permit No. WI-0000931-05-0 from outfall 002,

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which has been pass through NCCW all along (001 previously contained some treated process wastewaters). Available effluent data from outfall 002 is summarized in the following table:

January 2013 – September 2016 Ammonia Nitrogen Effluent Data Summary Sample size 43 Range < 0.25 – 0.83 mg/L

# of non-detects 30 1-day P99 0.70 mg/L Mean* 0.11 mg/L 4-day P99 0.40 mg/L

Standard Deviation 0.15 mg/L 30-day P99 0.21 mg/L

*Values lower than the level of detection were substituted with a zero These concentrations are low (as expected), and well below any of the applicable criteria or water quality-based effluent limits for the receiving water. Therefore, no water quality based effluent limits or monitoring for ammonia nitrogen are recommended for permit reissuance.

PART 4 –PHOSPHORUS

Revisions to administrative rules regulating phosphorus took effect on December 1, 2010. These rule revisions include additions to ch . NR 102 (s. NR 102.06), Wis. Adm. Code, which establish phosphorus standards for surface waters. Revisions to ch. NR 217 (s. NR 217, Subchapter III), Wis. Adm. Code, establish procedures for determining water quality based effluent limits for phosphorus, based on the applicable standards in ch. NR 102, Wis. Adm. Code.

Section NR 217.04(1)(a)2. Wis. Adm. Code states that an effluent limitation of 1.0 mg/L total phosphorus (technology based limit) shall apply in cases where an industrial facility discharges more than 60 pounds of total phosphorus per month except that outfalls consisting of noncontact cooling water without phosphorus containing additives may not be included in the calculation of the cumulative total mass loading of phosphorus discharged from the facility. This is reasonably understood to be the case for the surface water discharges at Valley Power Plant, because all process wastewater besides the cooling water is now directed to MMSD collection system.

Section NR 217.10(2), Wis. Adm. Code states that water quality based effluent limits (WQBEL) for total phosphorus apply to discharges of noncontact cooling water unless 100% of the phosphorus in the discharge originates from the receiving water as intake water. This is the case for the surface water discharges at Valley Power Plant, because all process wastewater besides the condenser cooling water is now directed to MMSD collection system. Conclusion: Based upon the operational change and the fact that the discharge from both outfall 001 and 002 are solely noncontact cooling water, no effluent limitations or monitoring for total phosphorus are required or recommended for permit reissuance. TMDL Under Development A third party (Milwaukee Metropolitan Sewerage District) Total Maximum Daily Load (TMDL) was developed for the Milwaukee, Menomonee, and Kinnickinnic River watersheds. The TMDL addresses phosphorus, TSS, and Fecal Coliform water quality impairments within these watersheds and provides waste load allocations (WLA) required to meet water quality standards. Because the discharge from We

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Energies Valley Power Plant is not considered to be a source of these pollutants, allocations were not included for any outfall in the draft TMDL report.

PART 5 –THERMAL

New surface water quality standards for temperature took effect on October 1, 2010. These new regulations are detailed in chs. NR 102 (Subchapter II – Water Quality Standards for Temperature) and NR 106 (Subchapter V – Effluent Limitations for Temperature) of the Wisconsin Administrative Code. Based upon the receiving water classification, daily maximum and weekly average temperature criteria are available for the 12 different months of the year. An initial evaluation using these updated materials was provided in the 2011 WQBEL memo. The permit issued effective January 1, 2013 included a compliance schedule for the facility to make changes to the system in order to meet the calculated WQBELs, or to apply for an alternative effluent limit under s. NR 106, Subchapter VI, Wis. Adm. Code and in accordance with 283.17 Wis. Stats. A thermal study plan was prepared by We Energies, AKRF, and HDR. The plan dated December 2013, was submitted in accordance with permit schedule 4.6 and was conditionally approved May 13, 2014. A number of activities were identified in a thermal study update, in order to support continuation of the temperature AEL in the next WPDES permit reissuance. Over 1,500 pages of related supporting material have been submitted with the permit application for WPDES Permit No. WI 0000931-06-0. Review of this information and its approval is beyond the scope of this WQBEL memo, as the AEL review and approval has been handled by Central Office Wastewater Staff in the past. Therefore, no recommendation related to the AEL request is provided in this memo. Upon review of effluent temperature data, there is reasonable potential for wastewater effluent to be discharged in excess of 120° F. Pursuant to s. NR 106.56(8),Wis. Adm. Code, a daily maximum limitation of 120° F is recommended for permit reissuance to ensure the protection of human health.

PART 6 – WHOLE EFFLUENT TOXICITY (WET)

WET testing is used to measure, predict, and control the discharge of toxic materials that may be harmful to aquatic life. In WET tests, organisms are exposed to a series of effluent concentrations for a given time and effects are recorded. The following evaluation is based on procedures in the Department's WET Program Guidance Document (revision #11, dated November 1, 2016). Acute tests predict the concentration that causes lethality of aquatic organisms during a 48 to 96-hour

exposure. In order to assure that a discharge is not acutely toxic to organisms in the receiving water, WET tests must produce a statistically valid LC50 (Lethal Concentration to 50 % of the test organisms) greater than 100 % effluent.

Chronic tests predict the concentration that interferes with the growth or reproduction of test organisms during a seven-day exposure. In order to assure that a discharge is not chronically toxic to organisms in the receiving water, WET tests must produce a statistically valid IC25 (Inhibition Concentration) greater than the instream waste concentration (IWC).

The IWC is an estimate of the proportion of effluent to total volume of water (receiving water + effluent). The IWC of 100 % shown in the WET Checklist summary below was calculated according to the following equation, as specified in s. NR 106.03(6), Wis. Adm. Code:

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IWC (as %) = Qe ÷ {(1 – f)Qe + Qs} × 100 Where: Qe = annual average flow = 61 MGD per unit, 95 MGD cumulative f = fraction of the Qe withdrawn from the receiving water = 1 Qs = 0 cfs for the South Menomonee Canal According to the State of Wisconsin Aquatic Life Toxicity Testing Methods Manual (s. NR 219.04,

Table A, Wis. Adm. Code), a synthetic (standard) laboratory water may be used as the dilution water and primary control in acute WET tests, unless the use of different dilution water is approved by the Department prior to use. The primary control water must be specified in the WPDES permit.

According to the State of Wisconsin Aquatic Life Toxicity Testing Methods Manual (s. NR 219.04, Table A, Wis. Adm. Code), the receiving water must be used as the dilution water and primary control in chronic WET tests, unless the use of different dilution water is approved by the Department prior to use. The dilution water used in WET tests conducted on outfall 001 shall be a grab sample collected from Lake Michigan, out of the influence of the mixing zone and any other known discharge. The specific receiving water location must be specified in the WPDES permit.

Shown below is a tabulation of all available WET data for outfall 001. Efforts are made to ensure that decisions about WET monitoring and limits are made based on representative data. Data which is not believed to be representative of the discharge is not included in reasonable potential calculations. The table below differentiates between tests used and not used when making WET determinations. At Valley Power Plant, process simplification was completed in late 2015 – early 2016 , so the last two results are representative of current conditions.

WET testing results at Valley Power Plant Outfall 001, January 2013 - Current

Date Initiated

Acute Results LC50 % (% survival in 100% effluent)

Chronic Results IC25 %

Footnotes

C. dubia Fathead minnow

Pass or Fail?

Use in RP?

C. dubia Fathead Minnow

Pass or Fail?

Use in RP?

02/05/2013 >100 >100 Pass Yes >100 >100 Pass Yes 06/03/2014 >100 >100 Pass Yes >100 >100 Pass Yes 09/15/2015 >100 >100 Pass Yes >100 >100 Pass Yes 12/06/2016 >100 >100 Pass Yes >100 >100 Pass Yes 01/31/2017 >100 >100 Pass Yes >100 >100 Pass Yes

WET reasonable potential is determined by multiplying the highest toxicity value that has been

measured in the effluent by a safety factor, in order to predict the likelihood (95% probability) of toxicity occurring in the effluent above the applicable WET limit. The safety factor used in the equation changes based on the number of toxicity detects in the dataset. The fewer detects present, the higher the safety factor, because there is more uncertainty surrounding the predicted value. WET limits must be given, according to s. NR 106.08(6), Wis. Adm. Code, whenever the applicable Reasonable Potential equation results in a value greater than 1.0. According to s. NR 106.08(6)(d), Wis. Adm. Code, TUa effluent values are equal to zero whenever toxicity is not detected (i.e. when the LC50, IC25 or IC50 ≥ 100 %.). Because all of the reported acute and chronic WET tests were “>100”, there is no acute or chronic reasonable potential, and limits are not required for permit reissuance.

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The WET Checklist was developed to help DNR staff make recommendations regarding WET limits, monitoring, and other permit conditions. The Checklist steps the user through a series of questions that evaluate the potential for effluent toxicity. The Checklist indicates whether acute and chronic WET limits are needed, based on requirements specified in s. NR 106.08, Wis. Adm. Code, and recommends monitoring frequencies based on points accumulated during the Checklist analysis. As toxicity potential increases, more points accumulate and more monitoring is recommended to insure that toxicity is not occurring. The completed WET Checklist recommendations for this permittee are summarized in the table below. Staff recommendations, based on the WET Checklist and best professional judgment, are provided below the summary table. For guidance related to RP and the WET Checklist, see Chapter 1.3 of the WET Guidance Document: http://dnr.wi.gov/topic/wastewater/WETguidance.html.

WET Checklist Summary – Valley Power Plant

Acute Chronic

AMZ/IWC No Acute Mixing Zone documented. 0 Points

IWC = 100 %. 15 Points

Historical Data

Passed all Acute WET tests taken over existing permit term(all “>100”). TOTAL POINTS = 0

Same (all “>100”). TOTAL POINTS = 0

Effluent Variability

No history of upsets or limit exceedances TOTAL POINTS = 0

Same as Acute TOTAL POINTS = 0

Receiving Water Classification

Full Fish and Aquatic Life TOTAL POINTS = 5


Chemical-Specific Data

Acute chlorine limit continued and no new limits for other substances (0 pts). Detects but no limits for toxics noted in Part 2 (3 pts). Six additional compounds of concern detected at low concentrations in priority pollutant scan (2 pts). TOTAL POINTS = 5

Chronic chlorine limit continued and no new limits for other substances (0 pts). Detects but no limits for other toxics noted in Part 2 (3 pts). Six additional compounds of concern detected at low concentrations in priority pollutant scan (2 pts). TOTAL POINTS = 5

Additives 1 biocide and 1 water quality conditioner TOTAL POINTS = 4 Same as Acute

TOTAL POINTS = 4

Discharge Category

No process wastewaters TOTAL POINTS = 0


Wastewater Treatment

Solely condenser cooling water TOTAL POINTS = 0


Downstream Impacts

None directly attributable to this discharge TOTAL POINTS = 0


Total Checklist Points: 14 Points 29 Points Recommended Monitoring Frequency (from Checklist):

None

3 test / 5 yr permit term (every other year)

Limit Required? No No TRE Recommended? (from Checklist)

No No

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If these recommendations were to strictly follow the guidance provided in the Department's WET Program Guidance Document (revision #11, dated November 1, 2016), the point totals generated by the WET Checklist, other information given above, and Chapter 1.3 of the WET Guidance Document; no acute and three chronic WET tests would be recommended for permit reissuance. However, the WET Checklist and supporting guidance in Chapter 1.3 were created to address standard discharge situations (for example, municipal and industrial process wastewaters). Staff may deviate from this guidance in situations where the basic assumptions it is based on do not seem to apply.

Explanation and comments about certain WET Checklist points for Outfall 001 5 points are given because of the detected substances as discussed in Part 2 15 points are given because there is no dilution (calculated IWC = 100 %)

Comment- These factors are critical to evaluating the potential for toxicity in more standard wastewater discharge situations like industrial or municipal treatment plant outfalls. However, they may not be as applicable to a condenser cooling water discharge, since extensive treatment typically would not be required in these situations, and no chemical or biological pollutants are added in the condenser cooling process. If these points were removed from the WET Checklist analysis, no acute or chronic WET testing would be recommended based upon the point totals since the potential for effluent toxicity appears to be low. This is consistent with available WET testing data as summarized earlier in Part 6. Therefore, no acute or chronic WET testing is recommended for permit reissuance. In summary, although acute and chronic WET testing has been required in the recent past for this facility for outfall 001, it is no longer necessary due to the simplification of the wastewater stream and the removal of water treatment additives like biocides or water quality conditioners besides sodium hypochlorite and sodium bisulfite for periodic mussel control on the intake structure.

PART 7 – ADDITIONAL EFFLUENT DATA

For informational purposes and with regard to the requirements in s. NR 201.03(6), Wis. Adm. Code, the following table illustrates the average concentrations and loadings at the facility from January 2013 through July 2017 for parameters proposed to be limited in WPDES Permit No. WI-0000931-06-0 ; Parameter Limit Average effluent value Footnotes Flow Rate No Limit 61 MGD @ outfall 001

61 MGD @ outfall 002 95 MGD all data combined

1 2

Chlorine Residual 19 μg/L daily max 7.3 μg/L weekly and monthly avg.

0 μg/L @ outfall 001 0 μg/L @ outfall 002

3

pH field 6.0 – 9.0 s.u. 7.86 s.u. @ outfall 001 (no data from outfall 002)

Temperature – Daily Maximum Temperature – Daily Average Heat

No Limit No Limit 1450 MBTU/hr (as a total from both outfalls)

71.2 F @ outfall 001 75.9 F @ outfall 002 64.5 F @ outfall 001 68.2 F @ outfall 002 378 MBTU/hr (as a total from both outfalls)

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Footnotes: 1. Days when either unit 1 or unit 2 were apparently idled or shut down were excluded from

calculation 2. This is the cumulative average of all reported flow from both unit 1 and 2. The average flow

from all reported days at unit 1 is 47.8 MGD and 47.4 MGD at unit 2. All values have been reported as non-detect for both unit 1 and unit 2 outfalls.

Attachment # 2 Site Map – Wisconsin Electric Power Co. Valley Power Plant


1

Attachment to Permit Fact sheet for Permit Number: WI-0000931-06-0 Permittee Name: Wisconsin Electric Power Company (We Energies) – Valley Power Plant Executive Summary Section 316(b) of the Clean Water Act requires that the location, design, construction, and capacity of cooling water intake structures reflect the best technology available for minimizing adverse environmental impact.1 The Department of Natural Resources (hereafter department) has made a Best Technology Available (BTA) determination for two cooling water intake structures (CWIS) located at Valley Power Plant (VAPP) in accordance with 40 CFR §125.90-98. The BTA for the two CWIS is based the required information submitted for a facility that withdraws greater than 2 MGD Design Intake Flow (DIF) and less than or equal to 125 MGD Actual Intake Flow (AIF) and uses greater than 25% for cooling. The department has concluded that the two recently modified CWIS at VAPP, consisting of fine mesh (2mm slot size) cylindrical wedge-wire screens and variable frequency drive pumps, is the best technology available for minimizing adverse environmental impact. The wedge-wire screens, installed in 2015 and 2016, meet the impingement mortality standard of 40 CFR §125.94(c)(2), 0.5 feet per second through-screen design velocity. The department has determined that no additional requirements of 40 CFR §125.94(c)(8), (c)(9) or (g) are required. The department must establish BTA standards for entrainment mortality reduction for each intake on a site-specific basis (40 CFR §125.94(d)). “The entrainment requirements must reflect the Director’s determination of the maximum reduction in entrainment warranted after consideration of factors relevant for determining the best technology available for minimizing adverse environmental impact at each facility.” 40 CFR §125.98(f). After consideration of the factors specified in 40 CFR §125.98(f)(2) and (f)(3), the department has concluded that the two recently modified CWIS at VAPP (fine mesh wedge-wire screens and variable frequency drive pumps) are considered the best technology available to achieve the maximum reduction in entrainment. The BTA determination will be reviewed at the next permit reissuance and at subsequent reissuances in accordance with 40 CFR §125.90-98 and state requirements, as applicable. In subsequent permit reissuance applications, the permittee shall provide all the information required in 40 CFR §122.21(r) and state requirements, as applicable, unless a request to reduce the information required has been submitted by the permittee and accepted by the department, as allowed by 40 CFR §125.95(c). Facility Background Valley Power Plant (VAPP) is a natural gas fired steam electric power generating plant that is a co-generation facility generating both electricity for the grid and steam for a downtown district heating system serving Milwaukee, Wisconsin. VAPP was built in 1968 to 1969 as a coal-fired power plant but converted to natural gas in 2014 and 2015. The facility consists of two units that each have two boilers and a steam turbine generator rated at 140 megawatts. Once-through non-contact cooling water is withdrawn from the Menomonee River and discharges to the South Menomonee Canal. The power plant

1 The department has the authority to regulate intake structures under s. 283.16(6) Stats. However, there are currently no state administrative rules to implement this section. Therefore the department is looking to the federal rules in 40 CFR Part 125, Subpart J as guidance.


2

and water intake operate continuously year-round. Electrical and steam demands may vary seasonally based on demand.

Description of Original CWIS, 2012 CWIS BTA Determination, and Recent CWIS Modifications

Original to the plant, the water intake facilities consisted of two identical intakes, one for each generating unit, located 400 feet apart along the Menomonee River. Steel sheet piling separated the river from the intake forebay. A horizontal opening in the steel sheet piling 39.5 feet long and 2.25 feet high was located 2 feet from the river bottom. The opening allowed water into the forebay (45 feet wide at the river, narrowing to 18 feet wide at the trash rack at a water depth of 15 feet). At the maximum design flow, the velocity through the sheet pile opening was 1.38 feet per second (fps). Vertical steel bar trash racks (18 feet wide by 11 feet high, with 0.75 inch bars and 3.12 inch openings) screened out large debris. At the maximum design flow rate, the velocity through the trash racks was 0.80 fps. Two parallel traveling water screens (6 feet wide with ⅜ inch mesh) filtered smaller debris to protect the circulating water pumps and condensers. At the maximum design flow rate, the velocity through the traveling water screens was 1.18 fps. Filtered debris was removed from the traveling water screens with a high pressure backwash system with a ¾ inch mesh wire basket strainer to remove debris before returning the backwash to the intake forebay. The traveling water screen was rotated and backwashed intermittently. Collected debris was taken to a landfill for disposal.

We Energies conducted an Impingement Mortality and Entrainment Characterization Study on the original CWIS and submitted results to the department on December 9, 2008 (Kinectrics 2008). Twenty-four-hour impingement samples were collected weekly from October 2006 through October 2007. The estimated annual impingement was 991,705 fish with a total biomass of 9,408 kilograms. Gizzard shad (a majority of which were juveniles) consisted of 95.3 percent of the impinged fish and 90 percent of the biomass. Alewife was the second most commonly impinged species (3.3 percent of individuals and 3.0 percent of biomass). The remainder of the impingement was distributed among 38 taxa. Both gizzard shad and alewife are not indigenous species to Lake Michigan, but they have value as forage fish for game species. The most abundant sport fish impinged was yellow perch at <0.5%.

During the Impingement Mortality and Entrainment Characterization Study, entrainment sampling was conducted weekly from April through September 2007 and monthly for the remaining months of the study period (November 2006 to November 2007). Based on the density of the organisms and intake flow rates, the total number of fish eggs and larvae entrained by the original VAPP CWIS in 2007 were estimated to be 255,837 and 5,699,325, respectively.

To provide a common frame of reference for assessing impacts, the number of fish impinged and entrained were converted to age-1 equivalents (i.e., the number of fish that would survive to be 1 year old), based on instantaneous mortality rates using the Equivalent Adult Model (EAM) (Horst 1975, Goodyear 1978, Dixon 1999) (Burns & McDonnell 2013). The EAM method, used by the U.S. Environmental Protection Agency (“USEPA”) in 20022 and 20143 provides a convenient means of converting losses of fish eggs, larvae, juveniles, and adults into units of individual fish and provides a standard metric for comparing losses among species, years, and regions. Mortality rates for each taxa

2 U.S. EPA. 2002. Case Study Analysis for the Proposed Section 316(b) Phase II Existing Facilities Rule. EPA-821-R-02-002. Office of Water. Washington, DC. 3 U.S. EPA. 2014. Benefits Analysis for the Final Section 316(b) Existing Facilities Rule. EPA-821-R-14-005. Office of Water. Washington, DC.


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impinged and entrained by the VAPP CWIS were obtained from USEPA (2002). Both the annual estimates and the annual estimated amount of age-1 equivalents impinged and entrained at VAPP in 2007 are presented in Table 1 below.

Table 1: Annual Estimate and Age-1 Equivalent Annual Estimate Impinged and Entrained by the Original VAPP CWIS Annual Estimate1 Age-1 Equivalent Impinged Fish2 991,705 138,978 Entrained Eggs 255,836 85 Entrained Larvae 5,699,325 33,449 TOTAL 6,946,866 172,512

1Annual Estimate includes long dead specimens. 2Majority of Impinged Fish were juvenile gizzard shad from one sampling event in Feb. 2007.

In 2006, We Energies conducted a screening level analysis of fish protection alternatives for the VAPP CWIS. Results of the analysis were submitted to the department in August 2006 as part of the Proposal for Information Collection (“PIC”) prepared as part of the CWA Section 316(b) Phase II Compliance Effort, and again on December 9, 2008, as part of the §283.31(6) Report. Assistance on the technical review of the water intake report, including an evaluation of the biological monitoring data, was provided by Tetra Tech, a USEPA consultant. Their review was completed with a final report sent to the department on June 24, 2010. On November 4, 2010, the department requested that We Energies evaluate the feasibility of retrofitting the CWIS with wedge-wire screens or other suitable technologies. In 2011, We Energies initiated a study to evaluate potential CWIS technology options to reduce the effects of impingement and entrainment. A Cooling Water Supply Options and 316(b) Control Technology Evaluation Phase II Report (Sargent & Lundy 2012) was provided to the department on March 21, 2012. Twenty-six (26) technologies were presented and screened, including modifications to the cooling system design, physical barriers, operational modifications, and behavioral barriers. A two-tier screening process was conducted. Tier I eliminated technologies that were not technically feasible, of unreasonable cost, and/or unable to accommodate constraints at the plant site. Following the Tier I evaluation, six alternatives remained and were examined using a weighted evaluation process to score alternatives on the basis of technical feasibility, effectiveness, economic criteria, and accommodation of site constraints. Cylindrical wedge-wire screens ranked the highest and variable frequency drive (VFD) pumps combined with other technologies came next.

In 2012, the department made a BTA Determination for the VAPP CWIS. The BTA Determination is described in the following department documents:

We Energies – Valley Power Plant Water Intake Structure BTA Determination, as part of the WPDES Permit Reissuance Fact Sheet Attachments, publicly noticed on August 15, 2012;

Notice of Final Determination to Reissue WPDES Permit No. WI-0000931-05-0, December 12, 2012;

Valley Power Plant WDPES Permit (WI-0000931-05-0), effective date January 1, 2013. Based on the department’s review of available information regarding the location, design, operation, capacity, and environmental impacts caused or contributed to by the intake structure, the department concluded that the original CWIS did not meet the requirements of s. 283.31(6), Wis. Statutes. We Energies was required to implement a technology to reduce impingement and entrainment mortality. The reissued WPDES Permit (effective date of January 1, 2013), required We Energies to install wedge-wire screens with a maximum design intake through-screen velocity of 0.5 fps. The BTA Determination was


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made using the department’s best professional judgement.4 The department relied on portions of the development documents from the EPA 316(b) Phase II Rule in 40 CFR Part 125 Subpart J (§125.90 through §125.99) to make the BTA Determination.

The permit also included a provision allowing the operation of an emergency water intake to allow river water into the forebay in the event the cylindrical wedge-wire screens are inoperable, or anticipated to be inoperable, due to clogging by frazil ice or debris, for essential maintenance, for periodic evaluation, or for other unanticipated emergency situations (see Permit Condition 1.7).

The WPDES Permit included a compliance schedule (see Permit Condition 3.1) to implement the wedge-wire screens, including submittal of a Technology Implementation and Operation Plan (“TIOP”) and completion of construction within 5 years (by December 31, 2017). We Energies submitted the TIOP on December 20, 2013 (Burns & McDonnell 2013), addressing the requirements in Permit Condition 1.4. The TIOP proposed a wedge-wire screen slot size of ⅛ inch (3.175 mm) and variable frequency drive pumps. The department approved the TIOP on March 10, 2014, and indicated that We Energies may proceed with the installation of the cylindrical wedge-wire screens at VAPP.

The USEPA Final Phase II 316(b) Rule was signed on May 19, 2014, published in the Federal Register on August 15, 2014 (see 79 Fed. Reg. 48300), and became effective on October 14, 2014. After conferring with USEPA Region 5, the department reaffirmed the BTA determination reached in 2012 requiring We Energies to install cylindrical wedge-wire screens with a design intake through-screen velocity of 0.5 fps. In a letter dated June 24, 2014, the department stated:

The department believes the current WPDES permit remains consistent with the final 316(b) rule. In other words, the department’s opinion is that We Energies’ proposal for improvements to the water intake represents the best technology available (BTA), and will be fully compliant with the new federal rules…During each future permit reissuance this BTA determination is subject to review.

On December 23, 2014, We Energies submitted a revised TIOP (Burns & McDonnell 2014), proposing design changes for the wedge-wire screens as a result of the Final Phase II 316(b) Rule. In particular, the TIOP proposed a slightly smaller slot size (2 mm) which would still achieve a low through-screen velocity and allow for a screen diameter that would maintain river navigation clearance desired by the Army Corps of Engineers and the Coast Guard. The smaller slot size corresponds to USEPA’s definition of fine mesh screens. The revised TIOP was approved by the department on January 7, 2015.

The Unit 2 CWIS was retrofitted in 2015 (startup occurred in September 2015) and the Unit 1 CWIS was retrofitted in 2016 (startup occurred in November 2016). A thorough description of the modified CWIS is provided in the following section.

Description of the Recently Modified CWIS at Valley Power Plant

As previously indicated, VAPP has two identical intake structures for cooling water located on the south side of the Menomonee River. The two CWIS were retrofitted with cylindrical wedge-wire screens in 2015 and 2016. During the CWIS retrofit project for each unit, the old opening in the sheet pile wall was

4In response to the Second US Court of Appeals’ decision on January 5, 2007, which remanded much of the 316(b) Phase II Rule, US EPA suspended the Phase II Rule on July 9, 2007, except for 40 CFR §125.90(b). In that section, US EPA authorized delegated permitting authorities to make BTA evaluations for existing facilities on a case-by-case basis using best professional judgement.


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sealed and three new, smaller openings were created at the screen attachment locations. Each CWIS consists of three wedge-wire screens, a forebay, an intake tunnel/piping, screening equipment, debris baskets, and circulating water pumps. Each cylindrical wedge-wire screen consists of two rotating, 74 inch diameter by 72 inch long cylinders connected to a tee manifold. The fine mesh wedge-wire screens have a slot size of 2 millimeters (mm). Fixed cleaning brushes are located on both the outside and inside of the cylinders to remove debris and biofouling from the screen surface and between the slots as the screens rotate. The center line of the wedge-wire screens is located 15.78 ft. below normal water level and 13.28 ft. below extreme low water level. The bottom of the screens is 3.22 ft. above the bottom of the Menomonee River. A vertical rail system is installed on the forebay sheet pile wall which allows the screens to be raised up and down with a hoist so that inspection and maintenance can be conducted when the screens are above water. When a single screen is removed, the isolation gate over the corresponding opening in the sheet pile wall is closed so the required intake flow will be routed through the two other screens. The isolation gates on the raised screens may be left open and operated as emergency intake sluice gates to ensure adequate flow to the intake. During use of the emergency intake, the existing trash racks and traveling water screens (previously described in the above section) are operated to protect the cooling water pumps from debris. As part of the CWIS retrofit project, the original circulating water pumps were replaced with new circulating water pumps with variable frequency drive (VFD) motors. Each CWIS has a maximum design through-screen velocity of less than 0.5 feet per second (fps) and the maximum flow rate for each CWIS is 86.1 million gallons per day (MGD) or 59,796 gallons per minute (gpm). §122.21(r) Studies Submitted

As part of the WPDES Permit Application, the permittee was required to submit information required under 40 CFR §122.21(r)(2) through (8). Based on a review of the flow monitoring data submitted to the department on the Discharge Monitoring Reports during the current permit term, the VAPP Actual Intake Flow (AIF) is below 125 MGD. As defined in 40 CFR §125.92(a), the AIF “means the average volume of water withdrawn on an annual basis by the cooling water intake structures over the past three years.” The calculated AIF are reported in Table 2 below. Because the AIF is not greater than 125 MGD the permittee was not required to submit information required under 40 CFR §122.21(r)(9) through (13).

Table 2: Calculated VAPP AIF Year Period of data used for AIF Calculation AIF (MGD) 2015 2013 – 2015 101.20 2016 2014 – 2016 106.70 2017 2015 – 2017 107.89

As part of the Application for WPDES Permit Reissuance submitted on June 30, 2017, We Energies provided the information required under 40 CFR §122.21(r)(2) through (8). A summary of the relevant application parts submitted are described below:

Attachment 4 of Permit Reissuance Application – Surface Water Intake Information. This addressed the requirements of 40 CFR §122.21(r)(2), (3), (5), (6) and (8) for the entire facility.

Attachment 5 of Permit Reissuance Application – Source Water Baseline Biological Characterization Data. This report, prepared by AECOM, addressed the requirements of 40 CFR §122.21(r)(4).


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Attachment 6 of Permit Reissuance Application – 316(b) Entrainment Performance Study Report.

This report, prepared by AECOM, was developed to document the entrainment performance of the cylindrical wedge-wire screens that were installed as part of the CWIS retrofit project at VAPP. The department recommended in an August 19, 2015 letter that entrainment monitoring be conducted to assist in making a determination as to whether the new intake structures are considered BTA for entrainment. This report addressed the requirements of 40 CFR §122.21(r)(7).

Additional submittals provided by the permittee included the following:

Attachment 3 of Permit Reissuance Application – Cylindrical Wedge-Wire Screen Velocity Verification Monitoring Report. This attachment to the Application for WPDES Permit Reissuance satisfies the requirements in Section 1.5.1 of the current VAPP WPDES Permit and Item 13 of the Detailed Surface Water Intake Information Section of the electronic application form for the permit reissuance.

Valley Power Plant WPDES Permit WI-0000931-04 Cooling Water Intake Evaluation. Email, April 16, 2010.

BTA Determination

In accordance with 40 CFR §125.94(a), VAPP is subject to the best technology available (BTA) standards for impingement mortality reduction under 40 CFR §125.94(c) and entrainment mortality reduction under 40 CFR §125.94(d), including any measures to protect Federally-listed threatened and endangered species and designated critical habitat established under 40 CFR §125.94(g). A discussion on the BTA standards for impingement mortality is discussed first followed by entrainment.

BTA Standards for Impingement Mortality

In accordance with 40 CFR §125.94(c), VAPP must comply with one of the alternatives in paragraphs (c)(1) through (7) of this section, except as provided in paragraphs (c)(11) or (12) of this section, when approved by the Director. In addition, a facility may also be subject to the requirements of paragraphs (c)(8), (c)(9), or (g) of this section if the Director requires such additional measures.

The permittee proposes 40 CFR §125.94(c)(2), 0.5 feet per second through-screen design velocity, as the BTA standard for impingement mortality. The department has evaluated this proposal under 40 CFR §125.94(c) approves this proposal. The department has determined that no additional requirements of 40 CFR §125.94(c)(8), (c)(9) or (g) are needed.

Both of VAPP’s CWIS are designed and operated to keep through-screen velocities at the intake less than 0.5 feet per second (fps). The maximum velocity must be achieved under all conditions, including during minimum ambient source water surface elevations and during periods of maximum head loss across the screens during normal operation. The Cylindrical Wedge-Wire Screen Velocity Verification Monitoring Report, submitted by We Energies as Attachment 3 of the WPDES Permit Application for Reissuance (We Energies 2017), provided the supporting calculations of the design through-screen velocity. In the Report, VAPP evaluated the through-screen velocity of three different operating scenarios (during periods of maximum head loss across the screens during normal operation):


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two (2) pumps in service at full speed and three (3) screens in service; one (1) pump in service at full speed and two (2) screens in service; and one (1) pump in service at full speed with three (3) screens in service.

The first scenario had the highest through-screen velocity. Each intake structure has two pumps, and when both pumps are in service (running in parallel) at full speed, the flow rate is 59,796 gpm. The maximum design intake flow (DIF) per CWIS is therefore 59,796 gpm or 86.1 MGD. The maximum design through-screen velocity when both pumps are in service at full speed and all three screens are in service is 0.35 fps.

When only one pump is in service at full speed, the flow rate is 36,000 gpm or 51.8 MGD. The maximum design through-screen velocity when one pump is in service at full speed and two screens are in service is 0.32 fps.

The final scenario is if only one pump is in service at full speed and all three screens are in service. The maximum design through-screen velocity in this scenario is 0.21 fps.

If two pumps are running and either one or two screens are in service, the through-screen velocity would be higher than 0.5 fps. Permit section 1.2.1.1 prohibits these scenarios from running for longer than one hour as it would negate the means of compliance for BAT for impingement.

When in operation, the wedge-wire screens remain fully submerged, even during periods of minimum source water elevation and maximum head loss across the screen. The center line for the screens is at elevation 563.79 ft. Since the screens have a 74 inch diameter, the top of each screen is at elevation 566.87 ft. The extreme low water level is at elevation 577.07 ft., which is at least ten (10) feet above the top of the screens. Therefore, the maximum velocities calculated are achieved under all conditions including periods of minimum source water elevation and maximum head loss across the screen during normal operation of the water intake.

The above design through-screen velocity calculations assume that the screens are completely clean (i.e., zero percent plugging). In the Cylindrical Wedge-Wire Screen Velocity Verification Monitoring Report, the permittee calculated the amount of debris that could plug the screens and still achieve a through-screen velocity of less than 0.5 fps. In the first scenario (2 pumps and 3 screens), the screens could sustain 29 percent plugging and still achieve a through-screen velocity of less than 0.5 fps. In the second scenario (1 pump and 2 screens), the screens could sustain 36 percent plugging and still meet the through-screen velocity standard. In the final scenario (1 pump and 3 screens), the screens could sustain 57 percent plugging and still achieve a through-screen velocity of less than 0.5 fps. The intakes are operated and maintained to minimize the amount of debris. As previously described, each screen is configured with a brush cleaning system to remove debris and maintain screen cleanliness. Weekly inspections conducted by the permittee verify the screen cleanliness.

According to the previous study done on entrainment and impingement, past impacts to the aquatic community from the operation of the VAPP CWIS were primarily due to impingement. In 2006-2007, estimated impingement mortality of Age-1 Equivalents at VAPP was approximately 414% greater in magnitude than entrainment. The permittee asserts that since the installation of the wedge-wire screens, most healthy fish have the ability to avoid impingement. In fact, data collected by USEPA shows that 96


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percent of studied fish can avoid an intake structure when the intake velocity is less than or equal to 0.5 fps.5

BTA Standards for Entrainment

The permittee proposes that the design and operation of the recently modified intakes meets the BTA standards for entrainment mortality reduction. The department has evaluated this proposal under 40 CFR §125.94(d) and the relevant factors in 40 CFR §125.98 and recommends the approval of this proposal. Below is a written explanation of the proposed entrainment determination as required by 40 CFR §125.98(f)(1).

For entrainment control, the regulations expressly call for the permitting agency to make a site-specific determination of which technologies and/or practices satisfy the BTA standard for each individual facility (40 CFR 125.94(d)). The BTA “must reflect the Director’s determination of the maximum reduction in entrainment warranted after consideration of the relevant factors as specified in 40 CFR §125.98.” 40 CFR §125.95(d). The regulations also give permitting authorities the discretion to “reject an otherwise available technology” as the BTA for entrainment if the social costs are “not justified” by the social benefits or if there are other unacceptable adverse factors that cannot be mitigated (40 CFR §125.98(f)(4)).

The proposed determination must be based on consideration of any additional information required by the Director and the factors listed in 40 CFR §125.98(f)(2). The weight given to each factor is within the Director’s discretion based upon the circumstances of each facility. In addition, the proposed determination may be based on consideration of the factors listed in 40 CFR §125.98(f)(3).

In accordance with 40 CFR §125.98(f)(2), the following factors must be considered:

(i) numbers and types of organisms entrained, including, specifically, the numbers and species (or lowest taxonomic classification possible) of Federally-listed, threatened and endangered species, and designated critical habitat (e.g., prey base);

(ii) impact of changes in particulate emissions or other pollutants associated with entrainment technologies;

(iii) land availability inasmuch as it relates to the feasibility of entrainment technology;

(iv) remaining useful plant life; and

(v) quantified and qualitative social benefits and costs of available entrainment technologies when such information on both benefits and costs is of sufficient rigor to make a decision.

In accordance with 40 CFR §125.98(f)(3), the following factors may be considered in determining a site-specific BTA:

(i) entrainment impacts on the waterbody;

(ii) thermal discharge impacts;

(iii) credit for reductions in flow associated with the retirement of units occurring within the ten years preceding October 14, 2014;

5 USEPA. Technical Development Document for the Final Section 316(b) Existing Facilities Rule. EPA-821-R-14-002. May 2014.


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(iv) impacts on the reliability of energy delivery within the immediate area;

(v) impacts on water consumption; and

(vi) availability of process water, gray water, waste water, reclaimed water, or other waters of appropriate quantity and quality for reuse as cooling water.

In the preamble to the 316(b) Rule, USEPA indicated the following:

The entrainment provision reflects EPA’s assessment that there is no single technology basis that is BTA for entrainment at existing facilities, but instead a number of factors that are best accounted for on a site-specific basis. Site-specific decision making may lead to a determination by the NPDES permitting authority that entrainment requirements should be based on variable speed pumps, water reuse, fine mesh screens, a closed-cycle recirculating system, or some combination of technologies that constitutes BTA for the individual site. The site-specific decision-making may also lead to no additional technologies being required.

79 Fed. Reg. 48300 at 48303. Candidate entrainment control technologies are provided in 40 CFR §122.21(r)(10), including a closed cycle recirculation system, fine mesh screens with a mesh size of 2 mm or smaller, and water reuse or alternate sources of cooling water. While VAPP is not subject to 40 CFR 122.21(r)(10) because the AIF is less than 125 MGD, the department believes that these candidate entrainment control technologies should be evaluated for the facility. In addition, variable speed pumps (i.e., variable frequency drive pumps) are another technology to consider. VAPP already has two of these technologies, fine mesh screens (wedge-wire screens with a mesh size of 2mm) and variable frequency drive pumps, installed and operational.

Entrainment Performance Evaluation of the Recently Modified CWIS

The discussion that follows combines 40 CFR 125.98(f)(2)(i) with (f)(3)(i), because there is overlap in the two factors.

FACTOR (f)(2)(i) Numbers and types of organisms entrained, including, specifically, the numbers and species (or lowest taxonomic classification possible) of Federally-listed, threatened and endangered species and designated critical habitat (e.g., prey base)

FACTOR (f)(3)(i) Entrainment impacts on the waterbody

An entrainment study conducted in 2016 evaluated the potential reduction of ichthyoplankton entrained at VAPP following installation of the wedge-wire screens. The VAPP 316(b) Entrainment Performance Study Report (AECOM 2017) was submitted to the department as Attachment 6 of the WPDES Permit Application for Reissuance.

Field samples were collected in accordance with a monitoring plan that was prepared by AECOM, submitted to the department by We Energies on December 14, 2015, and approved by the department on December 23, 2015. Samples were collected weekly during the months of April, May, July, and September 2016 and twice weekly in June and August 2016. The increased sampling frequency in June and August accounted for the peak in fish egg and larval entrainment recorded previously during the 2007 entrainment study (Kinectrics 2008). Samples were collected during the nighttime and daytime hours to account for diel periodicity, and paired sampling was conducted inside the forebay (to account for the actual amount ichthyoplankton entrained by the wedge-wire screens) and in the Menomonee River at the same depth of the screens.

Ichthyoplankton sampling within the forebay at VAPP collected 646 organisms representing nine identified taxa of fish (Bullhead catfish, Crappie sp., Herring sp. [alewife/gizzard shad], Minnow/Sucker


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sp., Round Goby, Shiner sp., Sucker sp., Sunfish sp., and Yellow Perch). A majority (94 percent) of the ichthyoplankton collected from the forebay samples were of four taxa: unidentified eggs; minnow/sucker eggs; alewife/gizzard shad larvae; and round goby larvae.

No threatened or endangered species were collected in any of the samples. There seemed to be no impact on designated critical habitat (e.g., prey base).

Based on the density of the organisms and the actual intake flow rates, the total number of fish eggs and larvae entrained by the fine mesh wedge-wire screens in 2016 were estimated to be 3,789,808 and 3,029,875, respectively. When compared to the annual estimates of eggs and larvae in the Menomonee River bottom layer, the 2 mm wedge-wire screens and variable speed pumps exclude approximately 90% of eggs and 69% of larvae/juveniles. Overall, the entrainment reduction of the wedge-wire screens is 85%. A summary of the annualized estimates and the percent reductions is included as Table 3 below. Note, when Round Goby, an invasive species, is not included in the analysis, the entrainment reductions improve by approximately two percent.

Table 3: VAPP 2016 Estimated Annual Entrainment and Percent Reduction When Compared to the Menomonee River Bottom Layer Ichthyoplankton Density (Table 3-9, AECOM 2017, emphasis added)

When converted to age-1 equivalents, the overall entrainment reduction is 78 percent (See Table 4 below).


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Table 4: VAPP 2016 Estimated Entrainment of Age-1 Equivalents Compared to the Menomonee River Bottom Layer Ichthyoplankton Density (Table 3-10, AECOM 2017, emphasis added)

In comparing the 2016 entrainment study (on the new wedge-wire screens) to the 2007 entrainment study (on the original CWIS), the egg count estimates are higher in both the Menomonee River (baseline) samples and Forebay (entrainment) samples. However, there was a reduction in the larval fish estimates in both the Menomonee River (baseline) samples and Forebay (entrainment) samples. The data are summarized in Table 5 below.

Table 5: VAPP Egg and Larvae Abundance Comparison Menomonee River (Baseline)1

Annual EstimateForebay (Entrainment) Annual Estimate

Original CWIS (2007 Study)2

Total Eggs 6,532,728 255,836 Total Larvae 24,431,069 5,699,325 TOTAL 30,963,797 5,955,162 Fine Mesh Wedge-Wire Screens (2016 Study)3

Total Eggs 36,957,647 3,789,808 Total Larvae/Juveniles4 6,986,323 2,011,571 TOTAL 43,943,970 5,801,379

1The Menomonee River estimates from the 2007 Study are based on samples collected at the surface level and the Menomonee River estimates from the 2016 Study are based on samples collected at the same depth of the wedge-wire screens (to capture the bottom layer densities). 2Kinectrics 2008 3AECOM 2017 4The comparison does not include Round Goby which are an invasive species.

When using the Age-1 Equivalent analysis, to provide a common frame of reference for assessing impacts, the annual estimated amount of age-1 equivalents entrained at VAPP in 2016 (after installation of the fine mesh wedge-wire screens) decreased by 70% when compared to the estimates entrained in 2007 (by the original CWIS). See Table 6 below for a summary of the data.

Table 6: Age-1 Equivalent Annual Estimate Comparison of Original CWIS with the Fine Mesh Wedge-Wire Screens Age-1 Equivalent Annual Estimate

Original CWIS (2007 Study)1

Fine Mesh Wedge-Wire Screens (2016 Study)2

Entrained Eggs 85 4,870 Entrained Larvae 33,449 5,3353

TOTAL 33,534 10,205 1Burns & McDonnell 2013 2AECOM 2017 3The comparison does not include Round Goby which are an invasive species.


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The department recognizes that entrainment reductions have been achieved after the installation of fine mesh wedge-wire screens, compared to the original VAPP CWIS.

Evaluation of Other Candidate Entrainment Control Technologies

Since VAPP recently installed fine mesh screens and variable frequency drive pumps, the department evaluated the other remaining candidate entrainment control technologies - closed cycle recirculation system, water reuse or alternate sources of cooling water - in order to make the BTA determination. Below is an evaluation of the technologies.

1. TECHNOLOGY: Mechanical draft cooling towers (closed-cycle recirculating system)

1.1. FACTOR (f)(2)(i) Numbers and types of organisms entrained, including, specifically, the numbers and species (or lowest taxonomic classification possible) of Federally-listed, threatened and endangered species and designated critical habitat (e.g., prey base).

Measurable entrainment reductions have been observed at VAPP since the installation of the fine mesh (2 mm) wedge-wire screens in 2015 and 2016. When compared to the annual estimates of eggs and larvae in the Menomonee River bottom layer, the 2 mm wedge-wire screens combined with the variable speed pumps exclude approximately 90% of eggs and 69% of larvae/juveniles. Overall, the entrainment reduction of the wedge-wire screens is 85%. Compared to the original CWIS, the magnitude of Age-1 equivalent fish entrained has reduced by 70%.

The annual entrainment estimates were calculated using actual intake flows at Unit 1 and Unit 2 in 2012, 2013, 2014, 2015, and 2016 to account for inter-annual differences. The average annual flow rate over these years was calculated to be 106.1 MGD, which is roughly two thirds of the facility wide Design Intake Flow (DIF) of 172.2 MGD. Therefore, theoretically, the 2016 annual entrainment estimate is roughly two thirds of the impact that might occur at design capacity.

Based on the results of the 2016 entrainment study, the near bottom Menomonee River ichthyoplankton composition consisted of 19.73 organisms/100 m3 and represented 11 identified taxa of fish (Minnow/Sucker sp., Herring sp. [alewife/gizzard shad], Round goby, Sunfish sp., Shiner sp., Gizzard shad, White sucker, Bluegill, Darter sp., Sucker sp., and Yellow perch). Therefore, an annual estimate of 46.7 million entrainable ichthyoplankton, composed of 79% eggs and 21% larvae/entrainable juveniles, are present in the Menomonee River (bottom layer).

A closed cycle system would significantly reduce entrainment. This is because entrainment reductions are directly proportional to flow reductions. As discussed in the 316(b) Rule Preamble, mechanical draft cooling towers operating in freshwater sources can achieve flow reductions of 97.5 percent (based on a cycle of concentration of 3.0). 79 Fed. Reg. 48300 at 48338. Therefore, USEPA estimates that freshwater cooling towers, compared to once-through cooling systems, reduce impingement mortality and entrainment by 97.5 percent.6 Using USEPA’s estimate of entrainment reduction and the 2016 entrainment study results, it is estimated that approximately 1.2 million ichthyoplankton would be

6 USEPA. Technical Development Document for the Final Section 316(b) Existing Facilities Rule. EPA-821-R-14-002. May 2014.


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entrained each year at VAPP if a mechanical draft cooling tower was installed (46.7 million x (100 – 97.5) ÷100).

The types of organisms entrained by a mechanical draft cooling tower would be similar to those found during the Menomonee River sampling in 2016. No federal or state threatened & endangered species are located in the nearby vicinity of the VAPP CWIS. See Attachment 5 to the WPDES Permit Application for Reissuance (Source Water Baseline Biological Characterization Data) for supporting information.

1.2. FACTOR (f)(2)(ii) Impact of changes in particulate emissions or other pollutants associated with entrainment technologies.

Mechanical draft cooling towers (closed-cycle recirculating system) result in increased environmental impacts to air, waste and water media. There would be increased energy use and increased chemical usage. A cooling tower would increase particulate emissions, which would likely require a minor source air permit. All mechanical cooling towers require motor driven fans which require a large amount of auxiliary power. Some degradation in overall plant efficiency would be expected. In addition, the fan noise can reach levels above 85 dBA. Therefore, sound attenuating insulation may be needed to reduce noise impacts. While it recognizes that there would be an increase in environmental impacts, the department does not believe that the impacts would be significant regarding the emission of particulates or other pollutants in light of the relatively small size of the power plant. Legionella contamination is an additional potential human health concern. See section 1.3 for discussion of vapor plume.

1.3. FACTOR (f)(2)(iii) Land availability inasmuch as it relates to the feasibility of entrainment technology.

There is sufficient amount of space available on the We Energies property to build a mechanical draft cooling tower. However, the land available is not appropriate to have a closed cycle cooling tower on it due to its very close proximity to a major interstate.

The biggest challenge in siting a cooling tower at VAPP is the plume. Because VAPP is in an urban setting and in close proximity to the I-94 and I-43 bridges that make up the “Marquette Interchange,” plume abatement technology would be required. Although plume abatement technology can greatly reduce the plume, there is no guarantee that it can be completely eliminated under all weather conditions. This is especially problematic as a winter exhaust plume could potentially result in ice formation on the nearby highways. In addition, a plume during any season could reduce visibility on the bridge. This creates a major safety concern.


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Siting of a cooling tower at VAPP would need to consider noise impacts, aesthetic impacts, and plume visibility in an urban area, as well as the potential for icing of the adjacent interstate. When the proximity of the major interstate is considered the department believes that the land availability is a significant factor weighing against mechanical draft cooling towers.

1.4. FACTOR (f)(2)(iv) Remaining useful plant life.

The department assumes that VAPP has a useful remaining plant life of at least several more five year permit terms, especially since the facility was recently converted from coal to natural gas and because it supplies all of the steam heat for the downtown Milwaukee heating district. Therefore, the department has determined that this is not a significant factor for consideration of closed-cycle recirculating system at VAPP.

1.5. FACTOR (f)(2)(v) Quantified and qualitative social benefits and costs of available entrainment technologies when such information on both benefits and costs is of sufficient rigor to make a decision.

This factor is highly dependent on intake flow. This factor is not used because information on benefits and costs is not of sufficient rigor to make a decision.

The permittee is not required to provide Cost Evaluation Study (40 CFR §122.21(r)(10)) or Benefits Evaluation (40 CFR §122.21(r)(11)) because AIF is less than 125 MGD. The permittee estimates that a cooling tower would require a significant capital cost investment ($40 to $68 million in 2010 dollars). In addition, there would also be increased O&M costs and the loss of revenue from electricity sales due to

Available Area

for Cooling

Tower

Major Interstate


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the de-rating (sometimes referred to as the “energy penalty”) caused by the operation of a cooling tower. O&M costs to operate and maintain the cooling tower are estimated to be about $200,000 per year. Lost generation revenue was estimated at about $600,000 per year for each 1% loss in generating capacity. Actual de-rate amounts will vary depending upon the season and intake water temperature. In general, this value will likely be at least $2 million per year. Operation of a plume abated system would increase the amount of de-rate/unit and therefore increase the lost generation revenue.

1.6. FACTOR (f)(3)(i) Entrainment impacts on the waterbody.

These were discussed and considered in the section titled Entrainment Performance Evaluation of the Recently Modified CWIS above.

1.7. FACTOR (f)(3)(ii) Thermal discharge impacts.

The cooling tower would reduce thermal discharge impacts. However, the facility has been granted an alternative effluent limit for temperature since they were able to demonstrate that the discharge is protective of a balanced indigenous community in the Menomonee River in their two studies done in 2011 and 2017. The department does not consider this a significant factor.

1.8. FACTOR (f)(3)(iii) Credit for reductions in flow associated with the retirement of units occurring within ten years preceding October 14, 2014.

This is not applicable for VAPP.

1.9. FACTOR (f)(3)(iv) Impacts on the reliability of energy delivery within the immediate area.

VAPP supplies all of the steam for the Milwaukee downtown district heating system, so its availability is critical to ensuring reliable energy is delivered within the immediate area. Outages to install or interconnect a cooling tower would need to be scheduled at certain times of the year, over multiple years (for both units) to ensure steam is available for We Energies customers at all times. While this would impact the technology installation timing, it does not preclude cooling towers. Therefore, this is not a significant factor.

1.10. FACTOR (f)(3)(v) Impacts on water consumption.

The cooling tower would result in increased water consumption as water would be lost to the atmosphere through evaporation instead of returned to the river. According to the Nuclear Regulatory Commission and the Electric Power Research Institute, water losses in a closed-cycle cooling system are approximately 60 – 80 percent greater than once-through cooling systems.7 At We Energies Pleasant Prairie Power Plant, which operated mechanical draft cooling towers, water consumption was approximately 75 – 90 percent. At Weston Power Plant, owned and operated by Wisconsin Public Service Corporation, water consumption ranges from 60 to 75 percent, and at Fox Energy Center, also owned and operated by Wisconsin Public Service Corporation, water consumption ranges from 75 – 85 percent. Once-through cooling causes evaporation of water too since the heated effluent plume 7 USEPA. Technical Development Document for the Final Section 316(b) Existing Facilities Rule. EPA-821-R-14-002. May 2014.


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evaporates more quickly than the ambient water temperature. The EPA estimates that the water lost through once-through cooling system is about 60% of the water that would be lost through a wet cooling tower.

Since an optimized mechanical draft cooling tower is estimated to achieve flow reductions of 97.5 percent, it is estimated that the DIF at VAPP would reduce from 172.2 MGD to 4.3 MGD. Of this flow, water consumption could be anywhere from 2.6 MGD to 3.9 MGD. Currently around 1.6 MGD would be lost with the once through operating at full potential

1.11. Summary/Conclusion.

A Mechanical Draft Cooling Tower would significantly reduce entrainment. However, other unacceptable adverse factors that cannot be mitigated make this technology unavailable at VAPP. The most unacceptable adverse factor is the location of the facility and the very close proximity to a bridge on a major interstate. While plume abatement technology would be required for the cooling tower, there is no guarantee that the plume would be completely eliminated under all weather conditions. This could create a major safety concern on the major interstate bridge due to reduced visibility and potential ice formation during winter. Additional factors contribute to making this technology infeasible, including:

Noise pollution, negative aesthetic impacts, and plume visibility in an urban setting; Potential human health concern from Legionella contamination in an urban setting; Increase in water consumption; Increase in particulate emissions (which would likely require a minor source air permit),

increased energy usage, and increased chemical usage; and Significant capital cost investment of $40 - $68 million (2010 dollars), along with annual O&M

costs and lost generation revenue due to de-rates from the energy penalty.

For all of these reasons, the department has rejected a mechanical draft cooling tower as an option for VAPP.


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2. TECHNOLOGY Water Reuse or Alternate Sources of Cooling Water

FACTOR (f)(3)(vi) Availability of process water, graywater, wastewater, reclaimed water, or other waters of appropriate quantity and quality for reuse as cooling water.

There is no available water for reuse that is of sufficient quantity and quality for reuse as cooling water at VAPP. In addition, there are no alternate sources of cooling water in the vicinity of VAPP that would provide sufficient quantity or quality for use at VAPP. The nearest potential source is Milwaukee Metropolitan Sewer District, but that is over a mile away, in an urban area and would need to cross a river and a canal. This makes it an infeasible source.

Entrainment BTA Decision

Mechanical Draft Cooling Towers were rejected as an option for the VAPP primarily due to the location of the facility and the very close proximity to a major interstate. The plume could create a major safety concern on the major interstate bridge due to reduced visibility and potential ice formation during winter. As discussed above, other factors also support the rejection of Mechanical Draft Cooling Towers.

There is no available water that is of sufficient quantity or quality for reuse as cooling water at VAPP.

The recently modified CWIS, consisting of fine mesh wedge-wire screens and variable frequency drive pumps, meets the BTA standards for entrainment. Entrainment reductions were observed in the 2016 VAPP 316(b) Entrainment Performance Study. Compared to the annual estimates of eggs and larvae in the bottom layer of the Menomonee River, the 2 mm wedge-wire screens achieved an overall entrainment reduction of 85% (approximately 90% of eggs and 69% of larvae/juveniles were excluded). Further, the Age-1 Equivalent analysis revealed that wedge-wire screens reduced the amount of age-1 equivalents entrained by the VAPP CWIS by 55% (compared to the original CWIS).

After consideration of the factors specified in 40 CFR §125.98(f)(2) and (f)(3), the department has concluded that the two recently modified CWIS (fine mesh wedge-wire screens and variable frequency drive pumps) are considered the best technology available to achieve the maximum reduction in entrainment at VAPP.


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SUMMARY

1. The department has made a Best Technology Available (BTA) determination for two cooling water intake structures (CWIS) located at Valley Power Plant (VAPP) in accordance with 40 CFR §125.90-98. The department has concluded that the two recently modified CWIS at VAPP, consisting of fine mesh (2mm slot size) cylindrical wedge-wire screens and variable frequency drive pumps, is the best technology available for minimizing adverse environmental impact.

2. The permittee proposes 40 CFR §125.94(c)(2), 0.5 feet per second through-screen design velocity, as the BTA standard for impingement mortality for each CWIS. The department has evaluated this proposal under 40 CFR §125.94(c) and recommends the approval of this proposal. The department has determined that no additional requirements of 40 CFR §125.94(c)(8), (c)(9) or (g) are needed.

3. After consideration of the factors listed in 40 CFR §125.98(f)(2) and (f)(3), the department has concluded that the two recently modified CWIS at VAPP (fine mesh wedge-wire screens and variable frequency drive pumps) are considered the best technology available to achieve the maximum reduction in entrainment.

4. BTA determinations will be reviewed at the next reissuance and at subsequent reissuances in accordance with 40 CFR §125.90-98 and state requirements as applicable. In subsequent permit reissuance applications, the permittee shall provide all the information required in 40 CFR §122.21(r) and state requirements as applicable, unless a request to reduce the information required has been submitted by the permittee and accepted by the department, as allowed by 40 CFR §125.95(c).

5. The BTA includes requirements for monitoring and inspection of the two CWIS and other requirements and terms; please see the draft permit.

CORRESPONDENCE / MEMORANDUM State of Wisconsin DATE: TO: Permit File FROM: Emma Lorenzen ‐ CO SUBJECT: Approval of the alternative effluent temperature limit for Valley Power Plant (WI‐0000931) Valley Power Plant (VAPP) is an existing facility pursuant to s. NR 106.71(3), Wis. Adm. Code, and

discharges heat and other pollutants to the South Menomonee Canal which flows into the Menomonee

River, which flows into Lake Michigan in Milwaukee, Wisconsin. In order to protect fish and aquatic life

in the South Menomonee Canal temperature limits were calculated for VAPP pursuant to ch. NR 106

Subchapter V, Wis. Adm. Code in 2011. This evaluation, using the protocols specified in Subchapter V,

determined that VAPP has reasonable potential to contribute to exceedances of both acute and sub‐

lethal thermal water quality standards in all months of the year, necessitating inclusion of temperature

limits in the permit. In accordance with Ch. NR 106 ‐Subchapter VI, 40 CFR Part 125, and Section 316(a)

of the federal Clean Water Act, VAPP requested alternative effluent limitations (AEL) for temperature

based on a demonstration that the calculated effluent temperature limits are more stringent than

necessary to protect fish and aquatic life. This was granted in 2012 with conditions for further

demonstration that it was protective of fish and aquatic life.

This demonstration entitled “Request For Renewal of The Alternative Effluent Limitation Under WIS. STAT. §283.17” was prepared by WE Energies, AKRF, and HDR and submitted to the Department of Natural Resources in June, 2017 and updated in August 2017. This report goes through the permit requirements for updating information to uphold the AEL that was granted in 2012. In order to demonstrate no appreciable harm to the balanced, indigenous community or to the list of

representative important species, this report covered the required actions of permit condition 3.2:

1. Assess the temperatures at locations in the mixing zone where the model predicted exceedances of the acute and sublethal thermal criteria (3.2a).

2. Assess the temporal variability of temperature in the Burnham and South Menomonee Canals and near field reaches of the Menomonee River up to the confluence with the Milwaukee River through continuous monitoring (3.2b)

3. Verify the existence of a zone of passage for aquatic life around the thermal discharge plume where the South Menomonee Canal joins the Menomonee River (3.2c)

4. Evaluate the extent of a zone of passage for the Burnham Canal and upper reaches of the South Menomonee Canal (3.2d)

5. Develop a plan for determining the potential changes in heat distribution in the Burnham Canal, South Menomonee Canal, and Menomonee River if the bottom topography in the Burnham Canal is adjusted as a result of the proposed wetland restoration in the Burnham Canal (3.2e).

6. Collect temperature and dissolved oxygen data to establish a profile horizontally and vertically in the Burnham Canal, South Menomonee Canal, and near‐filed reaches of the Menomonee River up to the confluence with the Milwaukee River. These profiles should reflect average and maximum temperature heat load conditions (3.2f).

7. Evaluate a variable heat load limit instead of the year‐round limit to assess the thermal plume variability at various heat load scenarios (3.2g).

8. Provide literature information on how the departure from normal seasonal water temperature caused by thermal discharge may impact the normal spawning, physiology, behavior, growth, and migration of the RIS (3.2 h).

9. Evaluate refinements of the amount of heat discharged to address the potential impacts of increased ambient water temperature and/or decreased flow in the Menomonee River that may occur in the future, and would be expected to reduce the amount of allowable heat discharged to protect aquatic life. A temperature limit expressed as the amount of heat discharged does not take into account changes in ambient temperatures and flow conditions; this needs to be accounted for (3.2i).

In the report, the facility verified the thermal model using the temperature collected. The model was then used to predict temperatures in the stream to show that there would be no harm to any of the RIS species in the Menomonee River. A zone of passage through the Menomonee River was also shown to exist for all fish on the RIS list at the confluence of the Menomonee River and South Menomonee Canal where the highest temperature in the river would occur. This was done by comparing the maximum temperature occurring in the model with the literature values of avoidance and lethal temperatures for the RIS list species. The representative important species (RIS) for this study was gizzard shad, northern pike, smallmouth bass, spottail shiner, walleye, white sucker, yellow perch, and side swimmer. This list of representative important species was approved by Paul Luebke on June 16, 2011 with confirmation that it was still valid given by Craig Helker on January 9, 2017. The department has concluded that the thermal plume created at 1,450 MBTU/hr will cause minimal impacts to the fish and invertebrate communities on the representative important species list. To accommodate operational flexibility the total heat discharged from both generating units 1 and 2 are regulated as one heat source to the Menomonee River, instead of individually, although they will be monitored separately. Outfalls 001 and 002 are adjacent to each other about 500 feet apart along the South Menomonee Canal and they may be considered as one, which is consistent with the approach taken with the hydrothermal modeling study. When both generating units are operating, the permitted heat load may be evenly split with 725 MBTU/hr between Outfalls 001 and 002, or other combinations that do not exceed a total of 1450 MBTU/hr. In the event only one generating unit is in operation, due to an outage of the other unit, the heat discharged may increase up to the design capacity for the one unit that is on‐line, which may be as much as 900 to 1000 MBTU/hr. In this next permit term, the department is requiring VAPP to do biological sampling in the mixing zone canal area, model potential zone of passage in the mixing zone during spring months, and to evaluate a variable heat load where heat loading is reduced during the months of March and April and how this may affect the zone of passage in the mixing zone area. With the upcoming construction of the Burnham Canal wetland we are proactively looking at zone of passage for fish, especially during key spawning times. Research at the UW‐Milwaukee School of Freshwater Sciences has shown that several panfish species are spawning in the Burnham and South Menomonee Canals which is something that was not considered in the original RIS list. In conclusion, the department agrees that a discharge of 1,450 MBTU/hr is protective of fish and aquatic life in the Menomonee River and that no temperature limit is needed. This decision will be re‐evaluated

by the department upon permit reissuance. Additional data should be submitted with the next permit application to continue to justify an alternative effluent limit to the department. If there are any questions or comments, please contact Emma Lorenzen at (608)‐267‐7643 or at

[email protected].

permit fact sheet general information - dnr.wi.gov · 01/12/2010 · the plant is fueled by natural...

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