NC0047384_Comments_20201230

DARSWEIL L.ROGERS,COMMISSIONER • /C FAYETTEVILLE PUBLIC WORKS COMMISSION
WADE R.FOWLER,JR.,COMMISSIONER 91. 955 OLD WILMINGTON RD
EVELYN O.SHAW,COMMISSIONER I •J P.O.BOX 1089
D.RALPH HUFF,III,COMMISSIONER H• OWN UTILITY FAYETTEVILLE,NORTH CAROLINA 28302-1089
DAVID W.TREGO,CEO/GENERAL MANAGER TELEPHONE[phone]
WWW.FAYPWC.COM
December 11, 2020
Ms. BriannaYoung RECEIVED
NC Division of Water Resources DEC 3 0
Water Quality Permitting Section 2020
1617 Mail Service Center NCDEQ/DWR/NpDES
Raleigh,NC 27699-1617
Subject: T.Z. Osborne WWTP SOC
Dear Ms. Young,
Fayetteville Public Works Commission (PWC) remains concerned about elevated loading of 1,4-
dioxane into the Cape Fear River. The Cape Fear River is the primary source of drinking water for
Fayetteville,and PWC continues to believe that a comprehensive watershed management strategy
for reduction of 1,4-dioxane is critical for the long-term protection of this resource. Fayetteville
PWC previously provided comments on the first proposed version of the Special Order by Consent
(SOC) for the City of Greensboro's (City) T.Z. Osborne WWTP (published for public comment
on June 22, 2020) by way of a letter dated July 23, 2020 (First Comments). Fayetteville PWC
incorporates its First Comments into the additional comments provided below regarding the
second version of the SOC (published for public comment on November 4, 2020).
First, Fayetteville PWC agrees with the underlying assumption of the second version of the SOC
that source reduction will be the most effective means of reducing 1,4-dioxane concentrations in
the Cape Fear River Basin. While the changes between the first and second versions of the SOC
certainly strengthen it,Fayetteville PWC is respectfully requesting the North Carolina Division of
Water Resources (DWR) consider the following additional comments:
1. The reduction of the compliance value in Year One of the SOC from 60 µg/L to 50 µg/L
remains too lenient. The City has demonstrated the ability to keep 1,4-dioxane levels in
their effluent well below 35 µg/1. We believe the City's effluent should be limited in a
manner that is consistent with the City's demonstrated ability to control 1,4-dioxane
discharge concentrations. It is PWC's understanding that the City has conducted source
evaluations and identified its primary source as Diamond Shamrock. PWC maintains that
Diamond Shamrock should be able to either stop treating waste streams that contain 1,4-
dioxane or utilize batch treatment and test that waste stream prior to discharge. As such,
there is no reasonable justification for allowing continued discharge of elevated levels of
1,4 dioxane from Diamond Shamrock's facility to the T.Z Osborne WWTP. Fayetteville
PWC continues to believe that the Year One compliance value should be 35 µg/L and that
the Year Two compliance value be capped at the current discharge levels i.e. 35 µg/L as
well.
BUILDING COMMUNITY CONNECTIONS SINCE 1905
AN EQUAL EMPLOYMENT OPPORTUNITY EMPLOYER

Ms. Brianna Young
December 11, 2020
Page 2
2. A long-term strategy and written plan to control loading to the Cape Fear River is needed.
DEQ's own data demonstrate that samples of waters downstream of the T.Z. Osborne
WWTP discharge show exceedances of EPA's health advisory concentration of 35 µg/L
for 1,4-dioxane. DEQ's data also demonstrate that the City is not the sole source of 1,4-
dioxane in the Cape Fear River. Without a comprehensive watershed management strategy
for controlling the total load of 1,4-dioxane discharged into the Cape Fear River, DEQ has
no rational basis to conclude that the SOC, even when combined with the reduction efforts
of other sources of this pollutant, will achieve sufficient load reductions to comply with
EPA's health advisory concentration.
3. DEQ should make available a watershed-wide water quality model or develop one if it has
not already done so, to give downstream drinking water suppliers real data regarding the
predicted 1,4-dioxane concentrations at times of critical flow at different locations along
the Cape Fear River(downstream of Reidsville and at drinking water intakes of the Town
of Pittsboro and Fayetteville PWC, for example). Because 1,4-dioxane does not break
down in the environment, a mass balance or spreadsheet approach to predicting
concentrations should be a good starting point for this modeling effort. This is possible
using each permitted discharge value (converted to cubic feet per second [cfs]), annual
average stream flows (cfs) at multiple river stations, and discharge concentrations (both
known and if limits were applied). DEQ should develop this watershed-scale analysis and
be transparent in its distribution of the results.
4. DEQ states that the initial and primary goal of this Special Order is that the City's effluent
discharge will not cause concentrations of the 1,4-dioxane in downstream drinking water
supplies to exceed the EPA health advisory concentration of 35 µg/L. Again,because the
City is not the only source of 1,4-dioxane in the watershed,use of a mass balance model is
necessary in order to conclude that the SOC will achieve DEQ's primary goal for it. Based
on the information currently available, Fayetteville PWC cannot weigh the likelihood that
downstream drinking water supplies will be protected, and it is unclear how DEQ can
either. A watershed-wide water quality model should be used to guide a science-based
approach for the development of a reliable and technically defensible watershed
management strategy for 1,4-dioxane. This plan must include reduction targets from the
major sources, a consistent plan for how to incorporate 1,4-dioxane into NPDES permits,
continued sampling, and a schedule to reliably meet the EPA health advisory for drinking
water.
5. Additional data reporting requirements should be incorporated into this SOC and any other
future SOCs for 1,4-dioxane in the Cape Fear River watershed so that the mass balance
model can be meaningfully updated. Transparency is needed to ensure public trust in the
process and to monitor progress against the strategy's timelines.
6. Fayetteville PWC recognizes DEQ's point that even with full source removal of 1,4-
dioxane from effluent discharges,there may"still be a background level present from other
historical sources in surface waters that prevent POTWs from obtaining the in-stream

Ms. Brianna Young
December 11, 2020
Page 3
Target Value of 0.35 µg/L in surface waters classified as water supply." However, in the
absence of a rulemaking proceeding to establish a numerical water quality standard for 1,4-
dioxane, Fayetteville PWC believes 0.35 ug/L should indeed be the Target Value used as
the basis of a watershed management strategy for 1,4-dioxane given the multiple drinking
water suppliers reliant on the Cape Fear River for their customers and the requirements of
15A NCAC 02B.0208(a)(2)(B) (prohibiting surface water standards for carcinogens from
causing an increased cancer risk greater than 1 in 1,000,000).
We reiterate that we believe each utility in the Cape Fear River watershed has an obligation to
work collaboratively to protect public health through the sharing of data, engagement in activities
such as the 1,4-dioxane stakeholder group and making earnest progress in limiting emerging
compounds in our public water supplies. We expect DEQ to continue to make water quality data
and the watershed-wide water quality model for the Cape Fear River watershed available in a
timely manner and to hold sources of these compounds accountable for their removal from
discharges.
Sincerely,
Fayetteville Public Works Commission
Mick Noland, PE
Chief Operations Officer
Water Resources Division
Fayetteville Public Works Commission
CC: Elaina Ball
James West
Sean Sullivan,Robinson Bradshaw
Jaime Robinson, CH2M Hill/Jacobs