NC0024406_Transmittal of Updated Combined Waste Formula Calculation_20201214

DUKE Duke Energy
Environmental Services
ENERGY® 410 S.Wilmington Street
Raleigh,NC 27601
December 4, 2020
Sergei Chernikov, Ph.D. RECEIVED
North Carolina Department of Environmental Quality
Division of Water Resources DEC 14 2020
1617 Mail Service Center
Raleigh, NC 27699-1617 NCDEQ/DWRINPDES
Subject: Transmittal of updated combined waste formula calculation
Belews Creek Steam Electric station
NC0024406
Stokes County
Dear Dr. Chernikov:
Attached please find an updated combined waste formula calculation for the subject facility.
This update calculates categorical limits based on the limits for FGD wastewater published in
the Federal Register on October 13, 2020. This is being provided as requested by the
Department when FGD landfill leachate was directed to the FGD wastewater treatment system
in 2019. Please incorporate into your review of our active permit modification request as you
determine appropriate.
Duke Energy is using the flow scenario identified as "Scenario#1" in the attached. We do not
anticipate use of or request any changes to the permit related to "scenario#2".
Sincerely,
E, Shannon Langley
Principal Environmental Specialist
Attachment
December 3, 2020 Addendum No. 1 from Dewberry Engineers
Cc: Lori Tollie/FileNet - via email
Brenda Johnson - via email
www.duke-energy.com

IN Dewberry
ADDENDUM NO. 1
Date: December 3, 2020
To: Derek Henderson
From: Amber Greune
Subject: Addendum No. 1 to Belews Creek FGD Treatment System Capacity Analysis Memorandum,
submitted December 13, 2019
Comments:
In the memorandum submitted to Duke on December 13, 2019, Dewberry calculated anticipated
numerical limits at the Belews Creek internal Outfall 002 based on the addition of leachate from the FGD
Landfill and Craig's Road Landfill and on the proposed Effluent Limitations Guidelines (ELGs)for Steam
Electric Power Generators published November 22, 2019 (Table 13). The ELGs were revised and the
2020 Reconsideration Rule was published October 13, 2020. Per Duke's request, Dewberry updated the
anticipated numerical limits at the Belews Creek internal Outfall 002 based on the numerical limitations for
FGD wastewater in the 2020 Reconsideration Rule. The updated anticipated limits are summarized in
Table 1.
Table 1.Anticipated FGD Concentration Limits and Calculated Alternative Concentration Limits
Based on ELGs •ublished October 13,2020.
Selenium Nitrate/Nitrite-N Arsenic Mercury
Scenario (µg/L) (mg/L) (µg/L) (ng/L)
Monthly Daily Monthly Daily Monthly Daily Monthly Daily
Avera•e Maximum Avera•e Maximum Avera•e Maximum Avera•e Maximum
Anticipated Outfall 002
Limits based on 2020 29 70 3 4 8 18 34 103
ELG revision
Speculative Scenario 1
Limits(FGD Landfill+ 25 61 2.6 3.5 7 16 30 89
FGD Blowdown)
Speculative Scenario 2
Limits(FGD and Craig's 23 55 2.4 3.2 6 14 27 81
Road Landfill+FGD
Blowdown)
Addendum No.1 11 of 1