NC0026123_Corrective Action Plan_20190821

Water Resources Division II;
146 N Church Street °.� !r Tel: [phone] Ext. 258
PO Box 1106 CITY OF
Asheboro, NC 27204-1106 Fax: [phone]
HEBO A n
S IZ
NORTH CAR O L I N A
August 21, 2019 RECEIVED/NCDEQ/DWR
AUG 2 7 2019
Water Quality
Permitting Section
Ms. Deborah Gore
PERCS Supervisor
North Carolina Environmental Quality
1617 Mail Service Center
Raleigh,NC 27699-1617
Re: Asheboro WWTP Permit No. NC0026123 1,4-Dioxane Corrective Action Plan
Dear Ms. Gore:
The City of Asheboro became aware that the Asheboro WWTP was discharging 1,4-Dioxane into
the Cape Fear River basin in early 2015. Trunk line monitoring, by method 8270 SIM, began in
March 2015 to identify potential sources within the Asheboro Collection System. A significant
source, Starpet Inc., was identified shortly thereafter. Asheboro pretreatment staff met with
industry staff and discussed ways to reduce or eliminate this compound. It was discovered that 1,4-
Dioxane was a byproduct of their manufacturing process and was not an additive chemical they
simply could substitute or eliminate. Industry staff voluntarily began researching treatment and/or
disposal options. No other contributing sources were found as a result of this monitoring.
Asheboro Staff continued sporadic trunk line and WWTP testing thru December 2017 at which
time NCDEQ Staff imposed monthly NPDES effluent testing for 1,4-Dioxane by new method
624.1. Asheboro continues to conduct monthly effluent sampling per NPDES permit requirements
and reports accordingly on the DMR. Asheboro has recently seen a reduction in effluent 1,4-
Dioxane concentrations, however, Asheboro Staff has no explanation for this reduction.
Starpet, Inc. has done extensive research on treatment options. There are few known treatment
technologies and locating a technology that they believe would work for their application proved
difficult. The City of Asheboro issued an Authorization to Construct to Starpet, Inc. on April 15,
2019 for the best treatment system they could locate and apply to their unique situation. Starpet,
Inc. expects their pre-built unit to be delivered in December 2019 for installation and setup.
Industry staff are optimistic it will be operational in late December 2019.
The City of Asheboro is confident that once treatment is installed and operating efficiently at
Starpet, Inc., Asheboro WWTP will see a dramatic decrease. in 1,4-Dioxane effluent
concentrations. Asheboro staff are hopeful that the combination of treatment and the recent
decreases in effluent concentrations that have already been observed will lower the concentration
for downstream users significantly.
Home of the NC Zoological Park

1,4 Dioxane Corrective Action Plan
8/21/2019
Page 2 of 2
The City of Asheboro appreciates the opportunity to work with NCDEQ during this new and
difficult time of addressing contaminants of emerging concern. It is Asheboro's hope that working
together with Industry, State,and local employees/officials we can all make our discharges cleaner
and safer for downstream communities. Please contact Sarah Laughlin, Technical Services
Specialist, at(336) 672-0892 ext. 218, if you need any additional information or have questions.
Sincerely,
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Michael D. Rhoney, P.E.
Water Resources Director
CITY OF
ASHEBOIU
WATER RESOURCES