Appendix F_20170421

�> ENERGY,
DUKE
Maruh e-4. &01 r
Mr. Jay Zimmerman
MuRM Carolina Department of Environmental Quality
Di.isiun of Water RasvarceS
1611 Mail Service Center
Raleigh, North Carolina 27699-1611
Subject: Water i reaimem System Evaluation for Aqua Wells
near Mr. cimmerman:
Peal Dnswitafi
senior vlce-Presi'aent
En ,enrnantal, Haam & s-toty
OW5 .SSvetri Unarel'i btrvet
Mail .tee KC3AP
cm-n.na, Ac 18Lp1
704-373-0408
In the Allen Proposed Permanent vvaier oolation Han submitted to NC DEQ on Decembur 7,
2016, Duke Energy recummundad that the thraa Aqua North Carolina, Inc. (Aqua) supply vvells
located within the H-uusw Bill 630 buandary be properly abandoned, with an interconnection
occurring between the Hqua system and the City of Belmont.
In NC DEQ's January 13, 2017 appruval of the Water 5uppiy Plans, IBC DEQ stated: "With
respect to the Allen Steam Station, the duterm;nzrtitun of v.hethur to provide wat`c, t,eait, ,,ent
davive.- for t:urn,,,unity supply wills ups, ated by Aqua lllarth Carulitjai _ Inc.. irlrermrrrtem the
distribot;vrt system to another pumic water supply system, or relocate the retells, �s duftnEd
pending furtharnaguNatier,a betwom, DEQ Duke Energy, at id Aqua North Ca, oh,ra_ /tree"
A meeting was Held in Raleigh on January 26, 2017 with rupraaantatives from NC DEQ, Duke
Energy, and Aqua attendi„g. Daring that meeting_ NC DEQ rque5ted that Duke Energy
prepare a U05L estimate for a water treatment system to be installed at the Aqua .all heads, in
order to treat ground..atur prier to it being dalivared t-v Aqua's ua5trjmum. That cost estimate is
attached. The estimate is for two systems because twt7 of the Aqua wells are connected and
can be treated witfl one system.
A few items of note:
1. Any Leatmant System design is highly dependent upon performance screening levels. Duke
Energy understan[!s that NC DEQ and NC DHHS are continaing tu d;ucasa the whole home
..star filtration system screening levels. For this evalaatia„_ Duke Energy used screening levels
of one-half of the MCL or the appropriate state standard, whichever is lu..ar, fur those
constituents that ..aru identified as potentially having a health concern in 2015 by NC DHHS.
The Federal Drinking Water Standard. the MCL; is tRe standard that will be met for all other
constituents. Fbr hexavalent chromium and vanadium, ..hich du nut have a MCL or a 2L value,
a value ;.,f 10 ppb was used fo, design purposes.
2. The ground..atar from the Aqua wells currently meets all Federal Drinking Water Standards.
One well had a vanadium rbDlt that was greater tffan the 10 ppm vanadium design laval;
therefore the design was based upon ruiduci„ g vanadium.

3. Duke E, targy was able to obtain access to the Aqua wells to rake additional samples on
March 14. eO i r. If the results from Me Marcn iq sampling event are different than what is
presented in this report, YYG ,,III lot NC DEQ kRvYY.
zF. Two ORerem water treatment systems were evaluated: ion enchanya, Y.hich is being atilir-ed
fti,r the ..hula hum systema, and an adsv, ptiun technology.
- Ion exchange:
- Estimated installation %-Mt: $538,000 and $565,000
- Esti,t,atad annual O&M cost: $77,000 and $93.000
- Adsorption:
- Estimated installation cast: $406,000 and $561,000
- Estimated annual O&M cult: $21.O1515 and $zu,0013
For both 5ystarn5, reganerata/backwash mate, ial will be captured in an above ground rank and
hauled Off -sire for disposdl on an estimated weekly Basis for ion exchange and on an estimated
monthly basis for adsor Ntiun. All other equipment could be hun5Ed in a small, pre-Gngincered
building installed near the well heads.
After DEQ provides the screaning Iavels, detailed design and bench scale tasting is warranted
prior to installation if this option is approved.
R—Wcommandat2lun
House Bill 630 gives a preference to a connection to a public water supply. Although Aqua is
regulated as a public Y.atur supply ar tity, and, therefore the households serviced by Aqua are
technically not eligible under House Bill 630, Duke Energy included these flousenolds in the
permanent water supply plans because Aqua I uce;vGd "DW Nut Drink- notificaativns in 2015 front
NC DEu and NC DHHS. Duke Energy has received feedback from homeowners that they
prefer connection to City of Belmont water over continued use of groundwater.
The �;ummanities served by the three Aqua wells are adjacent to the existing City or Belmont
water mains, and: dleremrs, an interconnect between the Aqua syater„s and the City of
Belmont main is the quickest permanent water solution. The installation of water treatment
syste, „s on these Aqua systems would be more expensive than the interconnect and would
taRe longer due to the need for bench uuala testing. Also, the weekly/monthly removal of
regenermte/backwash material and the presence of an above ground storage tank may fse not
be acceptable to homeowners in the area.
Duke Energy continues to propose that an interconnect occur between the Aqua system and
the City of Belmont water main. Wu haYu copied Aqaa un this letter and look fo, ward to
disc -,swing this issue with DEQ and Aqua. I will have Jessica Bednarcik, Duke project
man er. work with your team to setup a meeting in the near fatum.
Dv r
Paul Drauvitch
Senior Vice -President
Ert„ ircnm-ntal, Health & Safety
cc: Sheila Holman — Assistant Secretary, NC DEU
Jessica Bednarik — Doke Energy, EHS

JGssiva Gadreau — Division of Water Resources_ Public Water Supply Section
Debra Wa«s — Division of vvaier Resources, Animal Feeding Operations & Groundwater
PMt1ULti�.,n Branch
Shannon Becker— President Aqua North America, Inc.
Attachmem: Duke Potable — Aqua Community Weli i reatmeni System Evaluadon