NC0040797_Pretreatment_hwa_letter_20190718

ROY COOPER
Governor
MICHAEL S. REGAN
Secretary
LINDA CULPEPPER
Director
NORTH CAROLINA
Environmental Quality
July 18, 2019
Sent Via Electronic Mail ([e-mail])
David Cox
Pretreatment Coordinator
City of Hickory
310 Cloninger Mill Road
Hickory, NC 28601
Subject: Pretreatment Review of Headworks Analysis (HWA)
Program: City of Hickory, Catawba County
WWTP: Henry Fork WWTP - NPDES NCO040797
Dear Mr. Cox:
The Pretreatment, Emergency Response, and Collection Systems Unit (PERCS) of the Division of
Water Resources has reviewed the Headworks Analysis (HWA) for the City of Hickory — Henry
Fork WWTP - NPDES NC0040797. This HWA was received by the Division on June 27,2019.
The purpose of this submission is to update bis (2-ethylhexyl) phthalate data and to develop a
site removal rate for it. After reviewing the data, it is noted that all data were below detection
level (BDL), including plant influent and effluent, primary clarifier effluent and significant
industrial users (SIUs). The detection level for plant effluent was 0.005 mg/L, for other locations
were elevated because of matrix interference. A site specific removal rate could not be
determined by 100% BDL data, thus PERCS Unit believes that continuing sampling at plant
influent and SIUs does not provide useful information for the HWA. It is recommended that the
POTW continues to sample at plant effluent per the NPDES permit and remove bis (2-ethylhexyl)
phthalate from the long term monitoring plan. Once there is any hit at the plant effluent,
additional samplings would be required to find out the potential sources.
It is also noted that the uncontrollable flow was changed from 2.2001 MGD to 2.2253 MGD due
to the Longview Yarn SIU drop. Although little difference was made, it is recommended to keep
using the uncontrollable flow of 2.2001 MGD along with the uncontrollable concentrations as all
the other data was from 2014-2017. The PERCS' version of HWA was attached.
Next HWA Due Date will remain April 1, 2023 unless conditions at the POTW change significantly
and thus warrant an earlier submittal (see Comprehensive Guide, Chapter 5 Section D on PERCS
website).
Moan c wau nD Qi�
North Carolina Department of Environmental Quality Division of Water Resources
512 North Salisbury Street 1 1617 Mail Service Center Raleigh, North Carolina 27699-1617
919.707.9000

Thank you for your continued cooperation with the Pretreatment Program. If you have any
questions or comments, please contact me at [phone] [email: [e-mail]]
or Deborah Gore, Unit Supervisor at [phone] [email: Debora [e-mail]].
Sincerely,
DocuSigned�by:
Vivien Zhong, PERCS Unit
vz/hickory_henry_hwa_013 E42E88CDBD404A7...
Attached HenryFork_HWA_AT
EC with attachment: PERCS Unit file
Wes Bell, Mooresville Regional Office
EC: Central Files (Laserfiche)