NC0024228_Pretreatment_HWA_Letter_20200407

ROY COOPER
Governor
MICHAEL S. REGAN
Secretary
S. DANIEL SMITH
Director
NORTH CAROLINA
Environmental Quality
April 7, 2020
(sent via email: [e-mail])
Carrie Hyler, Pretreatment Supervisor
City of High Point
Public Services Department
P.O. Box 230
High Point, NC 27261
Subject: Pretreatment Review of Headworks Analysis - -Approved
Program: City of High Point
WWTP: Westside WWTP NPDES Permit No. NCO024228
Guilford County
Dear Ms. Hyler:
The Pretreatment, Emergency Response, and Collection Systems (PERCS) Unit of the Division of Water
Resources has reviewed the Headworks Analysis (HWA) for the City of High Point— Westside WWTP. This
HWA was received by the Division on November 19, 2019, with additional information and corrections
received on March 11, 2020, 2020, via email. We regret the delay in providing this approval.
The Division concurs with the HWA calculations for all pollutants of concern, with corrections discussed
below. These approved Maximum Allowable Headworks Loadings (MAHLs), Maximum Allowable
Industrial Loadings (MAILS), and the basis for these values are found on the last page of the enclosed HWA
spreadsheet. The results of the HWA are also listed in the bottom section of the enclosed Allocation Table.
Changes to the HWA Approved Today: Please feel free to contact PERCS if you have any questions
about the changes outlined below. All corrected spreadsheets were emailed to you for your files,
and other corrected documents were faxed. Please ensure the POTW's paper and electronic
HWA, AT, and other supporting documents contain these corrected documents, especially the
Allocation Table. As needed, please mark any original documents as "replaced" or "voided."
a. Design Values: The Design for TKN was entered for both Ammonia and Total Nitrogen.
b. Pass Through Loading and Metals Calculator: The Average Stream Flow was added and
the default upstream hardness of 25 mg/I were added. The resultant "Total Metal
allocated to permittee" values were entered into the HWA. Also, the Nickel stream
standard in the HWA was corrected to use the Aquatic Life Value as the WWTP's receiving
stream is Class C.
Over Allocation: The HWA shows over allocation for silver based on uncontrollable. Even
though the SIUs do not currently have limits for this parameter, the Division suggests the
POTW to switch current silver detection level (DL) from 5 ug/I to 1 ug/I, which is the
Division recommended lower PQL than the current model LTMP/STMP. Please note that,
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if all the influent data for silver is all less than the current best available detection level,
which is 1 ug/I, then the uncontrollable can be considered as zero, per PERCS. Please
submit an updated LTMP to reflect these changes.
2. HWA Due Date: The HWA approved today is primarily based on DMR/LTMP data for the period
of September 2018 through August 2019. Unless conditions at the POTW change significantly and
thus warrant an earlier submittal (see Comprehensive Guide, Section e), the POTW must submit
the following:
i. HWA due by December 31, 2024.
ii. It is noted that the current NPDES permit has expired. Upon receipt of your new
permit, please submit an updated HWA using any new NPDES limits as required
by Part IV, Section D, 4. Also, please submit an updated LTMP based on NPDES
permit renewal.
Federal and State pretreatment regulations require the local delegated pretreatment program to
effectively control and document the discharge of wastewater from Significant/Categorical Industrial
Users to the POTW. It is the POTW's responsibility to ensure that these objectives are consistently met.
Thank you for your continued cooperation with the Pretreatment Program. If you have any questions or
comments, please contact me at [phone] [email: Monti. [e-mail]].
."'Kptwby:
Manz: H-
866374CA4137482...
for S. Daniel Smith, Director
Division of Water Resources
Drf/highpoint. westside.hwa.2019
Attachments:
HighPoint.Westside.8.2.AlbemarleHWA.AT.2019_approvedApr7, 2020
High Poi ntWestside. Meta lsCalculator.approvedApril7,2020
ec: Central Files (LF)
Jim Gonsiewski, Winston Salem Regional Office (email)
PERCS Unit