NC0026441_Permit Modification_20100222

A7PA
NCDENR
North Carolina Department of Environment and Natural Resources
Division of Water Quality
Beverly Eaves Perdue Coleen H. Sullins Dee Freeman
Governor Director Secretary
February 22, 2010
Mr. Joel J. Brower
Town Manager
P.O. Box 769
Siler City, N.C. 27344-0769
Subject: Modification of NPDES Permit NCO026441
Resolution of Permit Adjudication
Siler City WWTP
Chatham County '
Dear Mr. Brower:
The Division issued the subject permit on August 29, 2008. The permit was
contested by Friends of the Rocky River. The case was subsequently heard before
Administrative Law Judge (ALJ) Beecher R. Gray in June 2009. ALJ Gray rendered a
decision recommending that the Environmental Management Commission (EMC) affirm
the reissuance of the permit. The EMC NPDES Committee adopted ALJ Gray's decision
on January 13, 2010. Therefore, the Division is issuing this permit modification. This
modification is issued pursuant to the requirements of North Carolina General Statute
143-215.1 and the Memorandum of Agreement between North Carolina and the U.S.
Environmental Protection Agency dated October 15, 2007 (or as subsequently amended).
This modified permit includes the following changes from the August 29,
2008 permit:
➢ The permit effective date has been changed to April 1, 2010.
➢ The footnotes in section A. (1) have been updated. They now include the revised
compliance threshold for Total Residual Chlorine (TRC).
If any parts, measurement frequencies or sampling requirements contained in this
modification are unacceptable to you, you have the right to an adjudicatory hearing upon
written request within thirty (30) days following receipt of this letter. This request must
be in the form of a written petition, conforming to Chapter 15UB of the North Carolina
General Statutes, and filed with the Office of Administrative Hearings (6714 Mail Service
Center, Raleigh, North Carolina 27699-6714). Unless such demand is made, this decision
shall be final and binding.
1617 Mail Service Center, Raleigh, North Carolina 27699-1617 One
512 Nodh' Salisbury Street, Raleigh, North Carolina 27604 North Carolina
Phone: [phone] / FAX [phone] / Internet: www.ncwaterquality.org
;Vatunally
An Equal Opportunity/Affirmative Action Employer— 50% Recycled/101% Post Consumer Paper

P&
This permit is not transferable except after notice to the Division. The Division
may require modification or revocation and reissuance of the permit. This permit does not
affect the legal requirements to obtain other permits which may be required by the
Division or permits required by the Division of Land Resources, the Coastal Area
Management Act or any other Federal or Local governmental permit that may be . , •
required.
If you have any questions concerning this permit, please contact Tom Belnick at
telephone number [phone].
13
Sincerely,
611
KColeeri H. Sullins
cc: Central Files
Raleigh Regional Office / Surface Water Protection
NPDES Unit
EPA Region IV / Marshall Hyatt f e-copy]
Aquatic Toxicology Unit [e-copy]
PERCS Unit / Sara Morrison [e-copy]
Nora Deamer / Basinwide Planning Program [e-copy]
Friends of the Rocky River R/o John D. Runkle, P.O. Box 3793, Chapel Hill, NC 27515-3793]

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y
Permit NCO026441
STATE OF NORTH CAROLINA
DEPARTMENT OF ENVIRONMENT AND NATURAL RESOURCES
DIVISION OF WATER QUALITY
17QT??%ATT
. TO DISCHARGE WASTEWATER UNDER THE.
NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM
NPDES
In compliance with the provision of North Carolina General Statute 143-215.1, other lawful standards and
regulations promulgated and adopted by the North Carolina Environmental Management Commission, and the
Federal Water Pollution Control Act, as amended, the
Town of Siler City
is hereby authorized to discharge wastewater from a facility located at the
Town of Siler City WWTP
370 Wastewater Plant Road
Chatham County
to receiving waters designated as Loves Creek within the Cape Fear River Basin, in accordance
with effluent limitations, monitoring requirements, and other�conditions set forth in Parts I, II,
III and IV*hereof.
This permit shall become effective April 1, 2010.
This permit and authorization to discharge shall expire at midnight October 31, 2011.
Signed this day February 22, 2010.
.( Coleen H. Sullins, Director
Division of Water Quality
By Authority of the Environmental Management Commission
Page 1 of 6

Permit N(` 02644-1
x
o_
SUPPLEMENT TO PERMIT COVER SHEET •
All previous NPDFS Permits issued to this facility, whether for operation or discharge are hereby revoked. As of this permit
issuance, any previously issued permit bearing this number is no longer effective. Therefore, the exclusive authority to operate
and discharge from this facility arises under the permit conditions, requirements, terms, and provisions included herein.
The Town of Siler City is hereby authorized to:
1. Continue discharging 4.0 MGD of treated process -contact and domestic wastewater from a
treatment facility consisting of
• Automatic and manual bar screens
• Grit collection unit
• Influent pump station
• Aerobic digester
• Filter backwash holding station
• DAF Unit
• Four (4) equalization basin
• Sludge transfer station
• Lime tower
• Alum feed station
• Dual oxidation ditches
• Dual secondary clarifiers
• Four (4) tertiary filters
• Chlorine contact chamber
• Sulfur dioxide addition
• Solids removal area (screened and separated; trucked offsite as byproduct)
This facility is 10; caled at the Siler City WWTP on Wastewater Plant Road'near Siler City in Chatham
County.
2. Discharge from said wastewater treatment works through Outfa11001 into Loves Creek (see
attached map), a stream classified as C waters within the Cape Fear River Basin.
Page 2 of 6

Permit NCO026441
A. (1) EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS
During the period beginning with the effective date and lasting until expiration, the Permittee is authorized to
discharge through Outfall 001. Such discharges shall be limited and monitored by the Permittee as specified
below:
PARAMETERS
EFFLUENT LIMITS
MONITORING REQUIREMENTS
Monthly
Average
Weekly
Average
Daily
Maximum
Measurement
Frequency
Sample
Type
Sample
Location'
Flow
4.0 MGD
Continuous
RecordingInfluent
or
Effluent
BOD, 5 day, 200C 2
.(April 1 thru October 31
5.0 mg/L
7.5 mg/L
Daily
Composite
Influent and
Effluent
BOD, 5 day, 20°C 2
November 1 thru March 31
10.0 mg/L
15.0 mg/L
Daily
Composite
Influent and
Effluent
Total Suspended Solids 2
30.0 mg/L
45.0 mg/L
Daily
Composite
Influent and
Effluent
NH3 as N .(April 1 thru October 31
1.0 mg/L
3.0 mg/L
Daily
Composite
Effluent
NH3 as N
November 1 thru March 31
2.0 mg/L
6.0 mg/L
Daily
Composite
Effluent
Fecal Coliform
eometric mean
200 / 100 ml
400 / 100 ml
Daily
Grab
Effluent
Total Residual Chlorine (TRC) 3
17 µg/L
Daily
Grab
Effluent
Temperature (°C)
Daily
Grab
Effluent
Dissolved Oxygen
Daily average > 6.0 mg/L
Daily
Grab
Effluent
pH
> 6.0 and < 9.0 standard units
Daily
Grab
Effluent
Total Nitrogen
(NO2 + NO3 + TKN)
Weekly
Y
Composite
p
Effluent
NO3-N + NO2-N (mg/L)
Weekly
Composite
Effluent
TKN (mg/L)
Weekly
Composite
Effluent
Total Phosphorus 4
(April 1 thru September 30
0.5 mg/L (quarterly average)
Weekly
Composite
Effluent
Total Phosphorus 4
October 1 through March 31
2.0 mg& (quarterly average)
Weekly
Composite
Effluent
,
Total Copper
2/Month
Composite
Effluent
Total Zinc
21Month
Composite
Effluent
Chloride
2/Month
Composite
Effluent
Chronic Toxicity5
Quarterly
Composite
Effluent
Effluent Pollutant Scan6
Annual
Grab
Effluent
Footnotes:
1. Instream monitoring shall be performed in accordance with A. (2).
2. The monthly average effluent BODS and Total Suspended Solids concentrations shall not exceed 15 % of the
respective influent value (i.e., 85% removal is required).
3. The Permittee shall report all effluent TRC values reported by a NC -certified laboratory [including field -
certified]. Effluent values below 50 µg/L will be treated as zero for compliance purposes.
4. Compliance with the Total Phosphorus limits shall be based on a calendar -quarter average of weekly samples.
5. Chronic Toxicity (Ceriodaphnia) at 90 %; quarterly during March, June, September, December [see A. (4)].
6. See A. (5).
Effluent shall contain no floating solids or foam visible in other than trace amounts.
Page 3 of 6

f .
Permit NCO026441
A. (2) INSTREAM MONITORING REQUIREMENTS
Parameter
Sample Type
Location'
Measurement FrequencyW
Dissolved Oxygen
Grab
LCU, LCD, RRU, RRD
3/ Week (June - September),
1/Week October -Ma
Temperature
Grab
LCU, LCD, RRU, RRD
3/ Week (June - September),
1/Week October -Ma
Total Phosphorus
Grab
LCU, LCD, RRU, RRD
Monthly
TKN
Grab
LCU, LCD, RRU, RRD
Monthly
NO3-N + NO2-N
Grab
LCU, LCD, RRU, RRD
Monthly
Footnotes:
1. LCU- Loves Creek, upstream of the discharge; LCD- Loves Creek, downstream of the discharge and above
the confluence with the Rocky River; RRU - Rocky River, upstream of the confluence with Loves Creek;
RRD - Rocky River, downstream of the confluence with Loves Creek.
2. Monitoring requirement takes effect April 1, 2009.
3. All monitoring is required to be performed at the abovementioned monitoring locations. Instream
Monitoring may be performed by the Upper Cape Fear River Basin Association as outlined in the
Memorandum of Agreement (MOA) between the association and the permittee. If so, the data is to be
collected and submitted to DWQ in accordance to the terms of the MOA. Should membership in this
association terminate for any reason, the permittee shall immediately notify the Division's NPDES Unit in
writing and resume responsibility to monitor and report the above parameters as specified in this permit.
A. (3) NUTRIENT REMOVAL OPTIMIZATION PLAN
Due to concerns about nutrient loads to Loves Creek and the Rocky River, the Siler City WWTP
is required to develop a Nutrient Removal Optimization Plan. This plan should evaluate
sources of nitrogen,(particularly nitrates) and phosphorus to the wastewater plant, provide
information on current removal rates, and discuss ways to optimize nutrient removal using the
current wastewater treatment process. This study shall be submitted within one year from the
effective date of this final permit.
A. (4) CHRONIC TOXICITY PERMIT LIMIT (Quarterly)
The effluent discharge shall at no time exhibit observable inhibition of reproduction or significant
mortality to Ceriodaphnia dubia at an effluent concentration of 90%.
The permit holder shall perform at a minimum, quarterly monitoring using test procedures outlined in
the "North Carolina Ceriodaphnia Chronic Effluent Bioassay Procedure," Revised February 1998, or
subsequent versions or "North Carolina Phase II Chronic Whole Effluent Toxicity Test Procedure"
(Revised -February 1998) or subsequent versions. The tests will be performed during the months of
March, June, September, and December. Effluent sampling for this testing shall be performed at the
NPDES permitted final effluent discharge below all treatment processes.
Page 4 of 6

Permit NCO026441 °
A. (5) EFFLUENT POLLUTANT SCAN
The permittee shall perform an annual Effluent Pollutant Scan for all parameters listed in the table below (in
accordance with 40 CFR Part 136). The annual effluent pollutant scan samples shall represent seasonal (summer,
winter, fall, spring) variations over the 5-year permit cycle. Unless otherwise indicated, metals shall be analyzed as
"total recoverable." Additionally, the method detection level and the minimum level shall be the most sensitive as
provided by the appropriate analytical procedure.
Ammonia (as N)
Trans-1,2-dichloroethylene
Bis (2-chloroethyl) ether
Chlorine (total residual, TRC)
1,1-diddoroethylene
Bis (2-chloroisopropyl) ether
Dissolved oxygen
1,2-dichloropropane
Bis (2-ethylhexyl) phthalate
Nitrate/Nitrite
1,3-dichloropropylene
4-bromophenyl phenyl ether
Total Kjeldahl nitrogen
Ethylbenzene
Butyl benzyl phthalate
Oil and grease
Methyl bromide
2-chloronaphthalene
Total Phosphorus
Methyl chloride
4-chlorophenyl phenyl ether
Total dissolved solids
Methylene chloride
Chrysene
Hardness
1,1,2,2-tetrachloroethane
Di-n-butyl phthalate
Antimony
Tetrachloroethylene
Di-n-"I phthalate
Arsenic
Toluene
Dibenzo(a,h)anthracene
Beryllium
1,1,1-tichloroethane
1,2-dichlorobenzene
Cadmium
1,1,2-trichloroethane
1,3-dichlorobenzene
Chromium
Trichloroethylene
1,4-dichlorobenzene
Copper
Vinyl chloride
3,3-dichlorobenzidine
Lead
Acid -extractable compounds:
Diethyl phthalate
Mercury
P-chloro-m-cresol
Dimethyl phthalate
Nickel
2-chlorophenol
2,4-dinitrotoluene
Selenium
2,4-dichlorophenol
2,6-dinitrotoluene
Silver
2,4-dimethylphenol
1,2-diphenylhydrazine
Thallium
4,6-dinitro-o-cresol
Fluoranthene
Zinc
2,4-dinitrophenol
Fluorene
Cyanide
2-nitrophenol
Hexachlorobenzene
Total phenolic compounds
4-nitrophenol
Hexachlorobutadiene
Volatile organic compounds:
Pentachlorophenol
Hexaddorocyclo-pentadiene
Acrolein
Phenol
Hexachloroethane
Acrylonitrile
2,4,6-triddorophenol
Indeno(1,2,3-cd)pyrene
Benzene
Base -neutral compounds:
Isophorone
Bromoform
Acenaphthene
Naphthalene
Carbon tetrachloride
Acenaphthylene
Nitrobenzene
Chlorobenzene
Anthracene
N-nitrosodi-n-propylamine
Chlorodibromomedme
Benzidine
N-nitrosodimethylamine
Chloroethane
Benzo(a)anthracene
N-nitrosodiphenylamine
2-ddoroethylvinyl ether
Benzo(a)pyrene
Phenanthrene
Chloroform
3,4 benzofluoranthene
Pyrene
Diddorobromomethane
Benzo(ghi)perylene
1,2,4-trichlorobenzene
.. 1,1-dichloroethane .
.Benzo(k)fluoranthene ,
1,2-dichloroethane
Bis (2-chloroethoxy) methane
0
Test results shall be reported to the Division in DWQ Form- DMR-PPA1 or in a form approved by the Director,
within 90 days of sampling. A copy of the report shall be submitted to Central Files to the following address:
Division of Water Quality, Water Quality Section,1617 Mail Service Center, Raleigh, North Carolina 27699-1617.
Page 6 of 6

Permit NC0026441
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 -February 1998) or subsequent versions.
The chronic value for multiple concentration tests will be determined using the geometric mean of the
highest concentration having no detectable impairment of reproduction or survival and the lowest
concentration that does have a detectable impairment of reproduction or survival. The definition of
"detectable impairment," collection methods, exposure regimes, and further statistical methods are
specified in the "North Carolina Phase II Chronic Whole Effluent Toxicity Test Procedure" (Revised -
February 1998) or subsequent versions.
All toxicity testing results required as part of this permit condition will be entered on the Effluent
Discharge Monitoring Form (MR-1) 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, DWQ Form AT-3
(original) is to be sent to the following address:
Attention: NC DENR / DWQ / Environmental Sciences Section
1621 Mail Service Center
Raleigh, North Carolina 27699-1621
Completed Aquatic Toxicity Test Forms shall be filed with the Environmental 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 Environmental 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.
Should any test data from this monitoring requirement or tests performed by the North Carolina
Division of Water Quality indicate potential impacts to the receiving stream, this permit may be re-
opened and modified to include alternate monitoring requirements or limits.
If the Permittee monitors any pollutant more frequently then required by this permit, the results of such
monitoring shall be included in the calculation & reporting of the data submitted on the DMR & all AT
Forms submitted.qS
NOTE: Failure to achieve test conditions as specified in the cited document, such as minimum control
organism survival, minimum control organism reproduction, and appropriate environmental controls,
shall constitute an invalid test and will require immediate follow-up testing to be completed no later
than the last, day of the month following the month of the initial monitoring.
Page 5 of 6

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Town of Siler City WWTP Facility
Location
Latitude: 35° 43' 45" N State Grid/Ound: E 21 N W / Siler City, NC not to scale
Longitude: 79° 25' 4T' W Permitted Flow:. 4.0 AGD NPDES Permit No. NCO026441 Receiving Stream: Loves Creek Drainage Basin: Cape Fear River Basin North]
Stream Class: C Sub -Basin: 03-06-12 LV th Chatham Count