NC0004979_Addendum to Permit App_20150520

Ots DUKE Duke Energy
ENERGY® 526 South Church Street
CAROLINAS Charlotte,NC 28202
Mailing Address:
EC3XP/P.O.Box 1006
Charlotte, NC 28201-1006
May 18, 2015 RECEIVED/DENRJDWR
mu 202015
Mr. Jeffrey Poupart, Section Chief
NC Division of Water Resources vvater Quality
1617 Mail Service Center Permitting Section
Raleigh, NC 27699-1617
Subject: Addendum to NPDES Waste Water Permit Application Permit
Chemical characterization of water for dewatering of ash basins
Allen Steam Station
NC0004979
Gaston County
Dear: Mr. Poupart,
Duke Energy hereby formally submits the attached characterization of ash basin free water and
ash basin interstitial water for the subject facility. These results were previously submitted to
your staff via email on May 8, 2015.
As discussed in various recent meetings between Duke and DENR staff, while there are no
current plans or commitments to dewater the ash basins at the subject facility, Duke request
that language be included in our re-issued NPDES permit to accommodate that activity if it an
activity the company decides to undertake within the term of the re-issued permit. As discussed
in the meetings, "dewatering" in the NPDES permits refers to the removal of interstitial water
from the ash basin(s).
The attached table provides results of chemical analysis of both ash basin free water and ash
basin interstitial water. The ash basin free water samples were taken at different depths in the
ash basin. The ash basin interstitial water samples results are presented 1.) without additional
treatment and 2.) after additional treatment with three different size filters.
The following definitions may be useful as you consider these activities:
Ash basin free water: Water in an ash basin located above the settled layer of ash.
Ash basin free water has undergone treatment in the ash basin, has the same general
characteristics as water routinely discharged from the facility in accordance with the
existing NPDES permit, is largely devoid of Total Suspended Solids and is expected to
meet all applicable NPDES permit limits.
Ash basin interstitial water: Water in an ash basin that is located within the pore
space of accumulated wastewater sludge or slurry. Ash basin interstitial water must be

removed from an ash basin by some means such as trenching, well points, etc. and
may require additional treatment before being released to the environment.
If you have any questions regarding this submittal, please contact Mr. Shannon Langley at (919)
546-2439 or [e-mail].
I certify, under penalty of law, that this document and all attachments were prepared under my direction or
supervision in accordance with a system designed to assure that qualified personnel properly gather and
evaluate the information submitted. Based on my inquiry of the person or persons who manage the system, or
those persons directly responsible for gathering the information, the information submitted is, to the best of my
knowledge and belief true, accurate,and complete. I am aware that there are significant penalties for
submitting false information, including the possibility of fines and imprisonment for knowing violations.
Sincerely,
J..„ -ii.,_:-
Harry K. Sideris
Senior Vice President,
Environmental, Health and Safety
attachment

Allen
Dewatering Data Submittal
May 2015
Allen Ash Allen Ash Allen Ash Basin Ash Basin- Ash Basin-Interstitial Ash Basin Ash Basin
Basin 0.3m Basin 3 meter 6 meter Interstitial with 20u filter Interstitial with Interstitial with
Component Units 10u filter 0.45u filter
Oil and Grease mg/L < 5
NO2/NO3(Colorimetric) mg-N/L 0.221 0.267 0.466 < 0.01 0.042 0.016 0.016
TKN(Colorimetric) mg-N/L 0.48 0.32 0.4 < 0.15 0.2 0.16 0.22
Bromide mg/L 2.506 3.058 17.4 0.1712 0.1613 0.1637 0.1732
Chloride mg/L 39.73 48.12 234.9 10.77 10.77 10.59 10.87
Fluoride mg/L 0.193 0.2083 0.5245 0.8935 0.8884 0.887 0.8915
Sulfate mg/L 44.6 47.55 103.1 47.77 47.76 46.92 47.71
Aluminum(Al) mg/L 0.101 0.09 0.051 0.9 0.874 0.23 0.184
Barium(Ba) mg/L 0.062 0.065 0.092 0.093 0.091 0.081 0.081
Boron(B) mg/L 0.899 1.06 4.86 r 0.638 0.631 0.622 0.642
Calcium(Ca) mg/L 32 35.3 127 24.7 24.4 24.6 25.1
Iron(Fe) mg/L 0.318 0.232 0.073 0.311 0.298 0.048 0.014
Magnesium(Mg) mg/L 7.92 9.35 38.3 4.29 4.28 4.19 4.31
Manganese(Mn) mg/L 0.242 0.252 0.261 0.037 0.036 0.034 0.035
Phosphorus(P) mg/L 0.031 0.021 < 0.02 0.728 0.72 0.701 0.72
Zinc(Zn) mg/L 0.01 0.01 0.014 0.005 < 0.005 < 0.005 < 0.005
Antimony(Sb) ug/L < 1 < 1 < 1 < 1 < 1 < 1 < 1
Arsenic(As) ug/L 4.27 3.59 1.95 862 874 856 865
Cadmium(Cd) ug/L < 1 < 1 < 1 < 1 < 1 < 1 < 1
Chromium(Cr) ug/L < 1 < 1 < 1 < 1 < 1 < 1 < 1
Copper(Cu) ug/L 1.56 1.39 1.1 1.65 1.53 < 1 < 1
Lead(Pb) ug/L < 1 < 1 < 1 < 1 < 1 < 1 < 1
Molybdenum(Mo) ug/L 8.79 8.42 11.2 81.3 81.8 80.4 82.1
Nickel(Ni) ug/L 4.67 5.01 5.63 1.31 1.23 < 1 < 1
Selenium(Se) ug/L 1.39 1.63 2.3 < 1 < 1 < 1 < 1
Thallium(TI)Low Level ug/L < 0.2 < 0.2 < 0.2 < 0.2 < 0.2 < 0.2 < 0.2
Vanadium(V) ug/L < 1 < 1 < 1 7.17 6.94 4.87 4.97
Mercury(CVAFS) ng/L 1.38 0.995 0.927 1.81 < 0.5 < 0.5 < 0.5
TDS mg/L 190 200 720 170 170 170 170
TSS mg/L < 5 < 5 < 5 18 16 < 10 < 10
pH SI Units 8.1 8.06 8 8.11