NC0025135_Fact Sheet_20221011

NCDEQ/DWR
FACT SHEET FOR NPDES PERMIT DEVELOPMENT
Huffman Finishing Company, Inc.
NC0025135
Facility Information
Applicant/Facility Name:
Huffman Finishing Company, Inc./ Huffman Finishing Company WWTP
Applicant Address:
P.O. Box 170, Granite Falls, NC 28630
Facility Address:
4919 Hickory Boulevard, Granite Falls, NC 28630
Permitted Flow
0.25 MGD to Catawba River
Type of Waste:
95% Industrial, 5% Domestic
Facility/Permit Status:
Grade II, Major/ Renewal
County:
Caldwell
Miscellaneous
Receiving Stream:
Catawba River
Regional Office:
Asheville
Stream Classification:
WS-IV, B, CA
8-digit HUC:
03050101
303(d) Listed?:
No
Permit Writer:
Sergei Chemikov, Ph.D.
Subbasin/Stream Index:
03-08-32/11-(53)
Date:
September 29, 2022
Drainage Area (mi2):
1090
Lat. 35° 45' 34" N Long. 81° 23' 48"W
Summer 7Q 10 (cfs)
40 (min. inst. release)
Winter 7Q 10 (cfs):
N/A
Average Flow (cfs):
N/A
IWC (%) @ 9.0 MGD:
0.96 %
Primary SIC Code:
2252
Background
Huffman Finishing, Inc. is a textile plant that manufactures hosiery and has requested renewal of their
existing NPDES permit. The applicable effluent guidelines are 40 CFR 410.52 (Textile Mills, Subpart E,
Knit Fabric). The facility has a designed flow of 0.25 MGD and its wastewater is 95% textile dyeing and
bleaching process wastewater and 5% domestic wastewater.
Huffman Finishing Company WWTP utilizes activated sludge to treat wastewater. Treatment consists of
the following components: vibrating screen, flow equalization basin with four floating aerators, lift
pumps, oxidation ditch, circular clarifier, sludge recirculation pumps, chlorine contact tank, ultrasonic
flow measurement, chemical dechlorination, cascade post aeration, aerobic sludge digester, sludge
holding lagoon, sludge drying beds, auxiliary power system.
The plant is located in the Subbasin 03-08-32 and discharges to the Catawba River (Lake Hickory)
approximately 2.5 miles below Rhodhiss Dam. This segment of the Catawba River is a class WS-IV, B;
CA waterbody. The receiving stream is not listed on the 2022 303(d) list as impaired. The outfall is
approximately one mile upstream from the water supply intake for the City of Hickory.
Page 1 of 5

NPDES Permit Fact Sheet - 11/28/22 Huffman Finishing
Page 2 NC0025135
Evaluation of Compliance Data
Discharge Monitoring Reports (DMRs) have been reviewed for the period of September 2017 through
September 2022. During that time no permit limit violation were reported.
The most recent facility inspection was conducted on January 10, 2022. The inspection report stated that
"The facility appeared well maintained and operated at the time of the inspection, and in compliance
with Permit NC0025135".
Evaluation of Instream Data
Instream monitoring is not required for this discharge.
Development of Effluent Guidelines
Applicable effluent guidelines are listed in 40 CFR 410.52 Textile Mills Subpart E, Knit Fabric.
Huffman Finishing Company was able to provide three years of yearly average product production (in
lbs/day). The averages were: 27,458 lbs/day in 2019, 18,987 lbs/day in 2020, and 21,850 lbs/day in
2021. The highest yearly average (27,458 lbs/day) was used to calculate the Technology Based Effluent
Limitations (TBELs) because production during 2020 and 2021 was significantly impacted by COVID
pandemic. Table 1 summarizes the proposed limit development based on the federal effluent guidelines.
For example, the BOD5 daily maximum limits in lbs per day = 5.0 (pounds per 1000 pounds of product)
* 27,458 (lbs/day) / 1000 = 137.5 lbs/day.
Table 1. TechnoloBased Effluent Limitations Calculation
Highest yearly average production 4 27,027 lbs/day
Pollutant
BPT limitations
(pounds per 1000 pounds of product)
Calculated Limits (lbs/day)
Daily Maximum
Monthly Average
Daily Max
Monthly Average
BOD5
5.0
2.5
137.5
68.8
COD
60.0
30.0
1650.0
825.0
TSS
21.8
10.9
599.5
299.8
Sulfide
0.20
0.10
5.5
2.8
Phenols
0.10
0.05
2.8
1.4
Total Chromium
0.10
0.05
2.8
1.4
pH
6.0 - 9.0 s.u.
Huffman Finishing Company also has 5% sanitary wastewater which could allow for extra allocations
for BOD and TSS; however, these additions were minor and were not added in this permit renewal.
Reasonable Potential (RPA) Analysis
The need for toxicant limits is based upon a demonstration of reasonable potential to exceed water
quality standards, a statistical evaluation that is conducted during every permit renewal utilizing the
most recent effluent data for each outfall. The RPA is conducted in accordance with 40 CFR 122.44 (d)
(i). The NC RPA procedure utilizes the following: 1) 95% Confidence Level/95% Probability; 2)
assumption of zero background; 3) use of detection limit for "less than" values; and 4) stream flows
used for dilution consideration based on 15A NCAC 2B.0206. Effective April 6, 2016, NC began

NPDES Permit Fact Sheet - 11/28/22 Huffman Finishing
Page 3 NC0025135
implementation of dissolved metals criteria in the RPA process in accordance with guidance titled
NPDES Implementation oflnstream Dissolved Metals Standards, dated June 10, 2016.
A reasonable potential analysis was conducted on effluent toxicant data collected between November
2017 and July 2022. Pollutants of concern included toxicants with positive detections and associated
water quality standards/criteria. Based on this analysis, the following permitting actions are proposed
for this permit:
• Effluent Limit with Monitoring. The following parameters will receive a water quality -based
effluent limit (WQBEL) since they demonstrated a reasonable potential to exceed applicable
water quality standards/criteria: None
• Monitoring Only. The following parameters will receive a monitor -only requirement since they
did not demonstrate reasonable potential to exceed applicable water quality standards/criteria,
but the maximum predicted concentration was >50% of the allowable concentration: Silver.
• No Limit or Monitoring: The following parameters will not receive a limit or monitoring, since
they did not demonstrate reasonable potential to exceed applicable water quality
standards/criteria and the maximum predicted concentration was <50% of the allowable
concentration: Cadmium, Total Phenolic Compounds, Chromium, Copper, Cyanide, Nickel,
Lead, Mercury, Selenium, Zinc, Sulfide, and Antimony.
Attached are the RPA results and a copy of the guidance entitled "NPDES Implementation of Instream
Dissolved Metals Standards Freshwater Standards."
Comparison of TBEL and WQBEL
A comparison table of proposed technology based effluent limits (TBELs) and water quality based
effluent limits (WQBELs) is reflected in Table 3. For parameters subject to both TBELs and WQBELs,
the more stringent limit shall be applied. In order to compare both effluent limits, the concentration
based limits (water quality limits) have been converted to the mass based limits using a permitted flow
of 0.25 MGD.
As shown in the Table 2, bolded parameter limits are more stringent limits and they will be applied in
the permit renewal.
Table 2. Comparison of TBEL and QWBEL
Parameter
TBEL (lbs/day)
WQBEL (mg/L)
WQBEL (lbs/day)
Daily
Maximum
Monthly
Average
Daily
Maximum
Monthly
Average
Daily
Maximum
Monthly
Average
BOD5
137.5
68.8
-
-
-
-
COD
1650.0
825.0
-
-
-
-
TSS
599.5
299.8
-
-
-
-
Sulfide
5.5
2.8
-
-
-
-
Phenols
2.8
1.4
-
31.3
-
65.0
Total
2.8
1.4
1.4 (Cr VI)
1.1 (Cr VI)
2.9 (Cr VI)
2.3 (Cr VI)

NPDES Permit Fact Sheet - 11/28/22
Page 4
Huffman Finishing
NC0025135
Chromium
Fecal
Coliform
-
-
400# /100 mL
200# /100 mL
-
-
TRC
-
-
28 ug/L
-
-
-
pH
6.0 - 9.0 s.u.
Mercury TMDL Evaluation
As required, the Permittee performed a low level effluent mercury test for submittal with the permit
renewal application. In accordance with the 2012 Mercury TMDL NPDES Guidance the permittee needs
to show annual mean effluent concentrations below both the Water Quality Based Effluent Limitation
(WQBEL) of 1250 ng/L and the Technology Based Effluent Limitation (TBEL) of 47 ng/L. The
effluent sample (5.74 ng/L) was below both the WQBEL and the TBEL, therefore, no mercury
limitation is required. Guidance for industrial wastewater treatment facilities does not require a Mercury
Minimization Plan if no limitation is needed. The permittee will be required to continue monitoring
mercury as part of its permit renewal, using EPA method 1631 E.
Toxicity Testing
Current Requirement: Chronic P/F @ 0.96% using Ceriodaphnia dubia.
Recommended Requirement: Chronic P/F @ 0.96% using Ceriodaphnia dubia.
This facility has passed all toxicity tests during the previous permit cycle, please see attached.
Basis for Permit Effluent Limits
• The limits for BOD, COD, TSS, Total Chromium, Sulfides, and Phenols are based on the
requirements codified in 40 CFR 410.52.
• The pH limits (Outfall 001) are based on the North Carolina water quality standards (15A NCAC
2B .0200).
• The TRC limit (Outfall 001) in the permit is based on the North Carolina water quality standards
[15A NCAC 2B .0211].
• Chronic Toxicity Limit in the permit is based on the 15A NCAC 2B .0200 et seq.
• Fecal Coliforms limits in the permit are based on the North Carolina water quality standards
[15A NCAC 2B .0211].
Summary of Proposed Changes
The following permit changes are proposed for this permit renewal:
1. Updated the electronic DMR requirement.
2. Updated the WET language.
3. The effluent limitations requirements for BOD5, TSS, COD, total chromium, sulfide, and phenol
were recalculated based on the current production.

NPDES Permit Fact Sheet - 11/28/22 Huffman Finishing
Page 5 NC0025135
Proposed Schedule of Permit Issuance
Draft Permit to Public Notice:
Permit Scheduled to Issue:
October 11, 2022 (estimate)
December 2, 2022 (estimate)
NPDES Division Contact
If you have questions regarding any of the above information or on the attached permit, please contact
Sergei Chernikov at [phone] or by email at [e-mail]