NC0024881_Pretreatment_HWA_Letter_20200110

ROY COOPER
Governor
MICHAEL S. REGAN
Secretary
LINDA CULPEPPER
Director
NORTH CAROLINA
Environmental Quality
January 10, 2020
Via Electronic Mail ([e-mail])
Ralph Potter
Pretreatment Coordinator
City of Reidsville
407 Broad St.
Reidsville, NC 27320
Subject: Pretreatment Review of Headworks Analysis
City of Reidsville, Rockingham County
NPDES #: NCO024881
Dear Mr. Potter:
The Pretreatment, Emergency Response and Collection Systems (PERCS) Unit of the Division of
Water Resources has reviewed the Headworks Analysis (HWA) submitted by the City of
Reidsville. This HWA was received by the Division via email on September 24, 2019. 1 apologize
for the late response.
The Division concurs with the HWA calculations for all pollutants of concern with observations
and corrections discussed below. These approved Maximum Allowable Headworks Loadings
(MAHLs), and the basis for these values are found on the last page of the HWA spreadsheet,
which has the corrections marked.
1) NPDES Limits for TN and TP: Please note for the following parameters if the POTW average
flow changes significantly and warrants a HWA modification, then the equivalent
concentration limits would need to be updated as well.
a) Total Phosphorus: The concentration limit is based on the 15,169 Ibs/year limit at the
current POTW average flow. The current MAHL is based on the NPDES loading as it is
more stringent than design criteria. The change does not add additional TP monitoring
requirements for Significant Industrial users (SIUs) at the moment.
b) Total Nitrogen: The concentration limit was added based on the 120,674 Ibs/year limit at
the current POTW average flow. The MAHL is based on the NPDES limit and there is no
design criteria.
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

2) NPDES Limit for Lead and Stream Standards: NPDES limit for Lead was removed as a renewed
NPDES permit has not been issued. Please make sure to submit a modified HWA to update
the NPDES limits and the dissolved metal stream standards within 180 days after the NPDES
permit is renewed. The calculator for the dissolved water quality standards was attached for
your reference.
3) Next HWA Due Date: The HWA was based on data from June 2016 — April 2019. Unless
conditions at the POTW change significantly and thus warrant an earlier submittal (see
Comprehensive Guide, Chapter 5), the POTW must submit an updated HWA on or before
September 30, 2024
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]].
Sincerely,
DocuSigned by:
Vivien Zhong, PERCS Unit
vz/reidsvilleHWA_008 IE42E88CDBD404A7...
ec: Central Files (LF)
PERCS Unit
Paul DiMatteo, Winston-Salem Regional Office