NC0020940_Technical Correction_20200210

ROY COOPER 'la,
Governor ' jgirl p
MICHAEL S.REGAN a ,=
Secretary ,
S.DANIEL SMITH NORTH CAROLINA
Director Environmental Quality
February 10, 2020
Ms. Anna Payne, Town Manager
Town of Murphy
P.O. Box 130
Murphy,North Carolina 28906
Subject: Technical Correction NPDES Permit
Permit NC0020940
Murphy WWTP
Cherokee County
Grade III Biological WPCS
SIC Code 4952
Dear Ms. Payne:
Division personnel have reviewed your permit and recognize that a footnote was omitted
regarding the total residual chlorine permit requirement, and the upstream hardness sampling type
was incorrect. The appropriate sheet has been corrected and is enclosed.
This technical correction does not affect any other terms, conditions,or compliance actions
covered by the permit.
If you have any questions concerning this permit, please contact Nick Coco at [phone] or
via email at [e-mail].
Sincerely,
aniel S , erector
ivision of Water Resources,NCDEQ
Hardcopy: NPDES Files
Central Files
Ecopy: DWR/Asheville Regional Office/Water Quality/Tim Heim
US EPA Region 4
North Carolina Department of Environmental Quality I Division of Water Resources
�/ 512 North Salisbury Street 11617 Mail Service Center I Raleigh,North Carolina 27699-1617
NORTH CAROLINA
n.o. dmEmmmr� 919.707.9000

Permit NC0020940
Part I
A.(1.) EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS (1.4 MGD)
[15A NCAC 02B .0400 et seq., 02B .0500 et seq.] Grade Ill Biological Water
Pollution Control System [15A NCAC 08G .0302]
During the period beginning on the effective date of the permit and lasting until expiration,the Permittee is
authorized to discharge treated domestic and industrial wastewater from outfall 001. Such discharges shall
be limited and monitored)by the Permittee as specified below:
.PARAMETER CHARACTERISTICS EFFLUENT LIMITS . • • MONITORING REQUIREMENTS
Parameter Code- Sample
Monthly Weekly ,Daily Measurement Sample
Average Average ; Maximum Frequency '. . . Type Location.
Flow 50050 1.4 MGD Continuous Recording Influent or
Effluent
BOD, 5-day,20°C2 C0310 30.0 mg/L 45.0 mg/L 3/Week Composite Effluent and
Influent
Total Suspended Solids(TSS)2 CO530 30.0 mg/L 45.0 mg/L 3/Week Composite Effluent and
Influent
Ammonia (NH3 as N),mg/L CO610 3/Week Composite Effluent
pH 00400 Between 6.0 and 9.0 standard units 3/Week Grab Effluent
Fecal Coliform 31616 200/100 400/100 3/Week Grab Effluent
(geometric mean) mL mL
Total Residual Chlorine3 50060 28 pg/L 3/Week Grab Effluent
Temperature(°C) 00010 Daily Grab Effluent
Total Mercury4 C0600 47 ng/L(annual average) Quarterly5 Composite Effluent
Total Silver, pg/L 01077 Quarterly5 Composite Effluent
Total Nitrogen(NO2+ C0600 Quarterly Composite Effluent
NO3+TKN),mg/L •
Total Phosphorus,mg/L C0665 Quarterly Composite Effluent
Total Hardness[as CaCO3]6, 00900 Quarterly Composite Effluent
mg/L
Chronic Toxicity 7 TGP3B/THP3B Quarterly Composite Effluent
Effluent Pollutant Scan NC01 Monitor&Report Footnote 8 Footnote 8 Effluent
Total Hardness[as CaCO3]9, 00900 Quarterly Grab Upstream
mg/L
Notes:
1. The Permittee shall submit discharge monitoring reports electronically using NC DWR's eDMR application system. See Special Condition A.(4.).
2. The monthly average BOD5 and Total Suspended Solids concentrations shall not exceed 15%of the respective influent value(85%removal).
3. Total residual chlorine is required only if chlorine is used as a disinfectant(or elsewhere in the process). The facility shall report all effluent
total residual chlorine values reported by a NC certified laboratory including field certified. However,effluent values below 50 µg/L will be
treated as zero for compliance purposes.
• 4. The test for Total Mercury shall be EPA Method1631 E.
5. Quarterly monitoring shall be conducted on the same months as chronic toxicity.
6. Effluent Total Hardness sampling shall be conducted in conjunction with effluent metals for the pretreatment program.
7. Chronic Toxicity(Ceriodaphnia)P/F at 2.2%;tests shall be conducted in March,June,September and December[see A.(2.)for further deiails].
Chronic toxicity sampling shall coincide with metals sampling.
8. The permittee shall perform three Effluent Pollutant Scans during the term of this permit[see A.(3.)].
9. The Permittee shall sample hardness upstream of the facility's discharge.The sample shall be representative of the hardness in the receiving
stream. If the Permittee is a member of the Monitoring Coalition Program,sampling for upstream hardness may be waived as long as the
Monitoring Coalition agrees to sample hardness at the nearest upstream location,at a minimum frequency of quarterly,and the Permittee has
obtained approval from DWR-NPDES Permitting Unit that the upstream station being monitored by the Coalition is representative of the
receiving stream for this discharge. The Permittee is responsible for submitting upstream hardness test results with its permit renewal
application package.If Coalition membership is cancelled or the Coalition terminates upstream hardness sampling at the approved station,the
Permittee will immediately notify the Division and resume sampling for upstream hardness,upstream of its discharge.
There shall be no discharge of floating solids or visible foam in other than trace amounts.
Page 3 of 9 Revised 2/10/2020

. Permit NC0020940
A.(2.) CHRONIC TOXICITY PERMIT LIMIT(Quarterly)
[15A NCAC 026.0200 et seq.]
The effluent discharge shall at no time exhibit observable inhibition of reproduction or significant mortality
to Ceriodaphnia dubia at an effluent concentration of 2.2%.
The permit holder shall perform at a minimum, quarterly monitoring using test procedures outlined in the
"North Carolina Ceriodaphnia Chronic Effluent Bioassay Procedure," Revised December 2010,or
subsequent versions or"North Carolina Phase II Chronic Whole Effluent Toxicity Test Procedure" (Revised-
December 2010) or subsequent versions.The tests will be performed during the months of March,June,
September and December. These months signify the first month of each three-month toxicity testing
quarter assigned to the facility. Effluent sampling for this testing must be obtained during representative
effluent discharge and shall be performed at the NPDES permitted final effluent discharge below all
treatment processes.
If the test procedure performed as the first test of any single quarter results in a failure or ChV below the
permit limit,then multiple-concentration testing shall be performed at a minimum, in each of the two
following months as described in"North Carolina Phase II Chronic Whole Effluent Toxicity Test
Procedure"(Revised-December 2010)or subsequent versions.
All toxicity testing results required as part of this permit condition will be entered electronically using the
Division's eDMR system for the months in which tests were performed, using the parameter code TGP3B
for the pass/fail results and THP3B for the Chronic Value.Additionally, DWR Form AT-3 (original) is to be
sent to the following address:
Attention: North Carolina Division of Water Resources
Water Sciences Section/Aquatic Toxicology Branch
1621 Mail Service Center
Raleigh, NC 27699-1621
Or, results can be sent to the email,[e-mail].
Completed Aquatic Toxicity Test Forms shall be filed with the Water Sciences Section no later than 30 days
after the end of the reporting period for which the report is made.
Test data shall be complete, accurate, include all supporting chemical/physical measurements and all
concentration/response data,and be certified by laboratory supervisor and ORC or approved designate
signature. Total residual chlorine of the effluent toxicity sample must be measured and reported if chlorine
is employed for disinfection of the waste stream.
Should there be no discharge of flow from the facility during a month in which toxicity monitoring is
required,the permittee will complete the information located at the top of the aquatic toxicity(AT)test
form indicating the facility name, permit number, pipe number,county,and the month/year of the report
with the notation of"No Flow" in the comment area of the form. The report shall be submitted to the
Water Sciences Section at the address cited above.
Should the permittee fail to monitor during a month in which toxicity monitoring is required, monitoring
will be required during the following month.Assessment of toxicity compliance is based on the toxicity
Page4of9