NC0047597_Permit Modification_20130124

ATA
rENR
North Carolina Department of Environment and Natural Resources
Division of Water Quality
Pat McCrory Charles Wakild, P. E. John E. Skvarla, III
Governor Director Secretary
January 24, 2013
Charles Cocker, Superintendent
City of Durham Department of Water Management
101 City Hall Plaza
Durham, North Carolina 27701
Subject: Modification of Permit NC0047597
South Durham WRF
Class IV Facility
Dear Mr. Cocker:
Division of Water Quality (Division) personnel have reviewed and approved your request for a
modification of the subject permit. Accordingly, we are forwarding the attached NPDES
discharge permit. It 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.
This permit modification grants your request for a reduction in the monitoring frequency for total
mercury from monthly to quarterly. It also contains the following changes pursuant to the
recently approved statewide TMDL for mercury:
• Special condition A (10) has been added requiring a mercury minimization plan (MMP).
• Limits for total mercury have been changed to an annual average limit of 12 ng/L.
This permit is not transferable except after notifying the Division of Water Quality. The Division
may modify and reissue or revoke this permit. Please note that this permit does not affect your
legal obligation to obtain other permits required by the Division of Water Quality, the Division of
Land Resources, the Division of Coastal Management, or other federal or local agencies.
1617 Mail Service Center, Raleigh, North Carolina 27699-1617
Location: 512 N. Salisbury St. Raleigh, North Carolina 27604
Phone: [phone] FAX: [phone]
Internet www.ncwaterauality.orq
Wone CaT01]T1S
7s7aturaI4i
An Equal opportunity l Affirmative Action Employer

If you have questions, or if we can be of further assistance, please contact Mr. Gil Vinzani at
[[e-mail]] or at telephone number [phone].
Sincerely,
Mtk
�x Charles Wakild, P. E., Director
Division of Water Quality
Enclosure: NPDES Permit NC0047597
Cc: Raleigh Regional Office, Surface Water Protection Section*
NPDES Files
Central Files
* E-mail copy

Permit No. NC0047597
STATE OF NORTH CAROLINA
DEPARTMENT OF ENVIRONMENT AND NATURAL RESOURCES
DIVISION OF WATER QUALITY
PERMIT
TO DISCHARGE WASTEWATER UNDER THE
NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM
In compliance with the provisions 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
City of Durham
is hereby authorized to .discharge wastewater from a facility located at the
South Durham Water Reclamation Facility
6605 Farrington Road
Chapel Hill, NC
Durham County
to receiving waters designated as an unnamed tributary to New Hope Creek in 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 February 1, 2013.
This permit and authorization to discharge shall expire at midnight on April 30, 2016.
Signed this day January 24, 2013:
rles Wakild, P. E., Director
Division of Water Quality
By Authority of the Environmental Management Commission

Permit No. NC0047597
SUPPLEMENT TO PERMIT COVER SHEET
All previous NPDES 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 City of Durham
is hereby authorized to:
1. Continue to operate an existing 20.0 MGD wastewater treatment facility consisting of the following:
• Mechanically cleaned bar screens
• Long channel grit chambers
• Primary clarifiers
• Aeration basins
• Final clarifiers
• Flocculation basins
• Traveling bridge effluent sand filters
• UV disinfection
• Anaerobic digesters
• Aerobic digesters
• Gravity belt thickener
• Clarifier
• Sand drying beds
• Belt filter press
Facility is located at 6605 Farrington Road, Chapel Hill, NC, in Durham County, and
2. Discharge from said treatment works at the location specified on the attached map into an unnamed
tributary to New Hope Creek, classified WS-IV NSW waters in the Cape Fear River Basin.

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South Durham WRF - NC0047597
Facility :` •
USGS Quad Name: Southwest Durham
Receiving Stream: New Hope Creek
Lat.: 35°58'18"
Long.: 78°58'28"
Location •
'
Stream Class: WS-IV NSW
Subbasin: Cape Fear - 030605
HUC: 03020101
North
SCALE 1:24,000

Permit No. NC0047597
A (1) EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS
Beginning upon the effective date of this permit and lasting until expiration, the Permittee is authorized
to discharge treated wastewater from Outfall 001. Such discharges shall be limited and monitored by
the Permittee as specified below:
r ; ;. ;
EFFLUENT
CHARACTERISTICS_
';� �' .
. EFFL-UENTLI{IITAATIO?NS ,
: MONfTQRING REUIREMENTS_
Monthly
Average' '
Weekly
'' Average• '
Daily
Max rlio
t 4
Measurement'
Frequency
Sam !eT"-el..
P '
'Sampte1
f Locafioh
Flow
20.0 MGD
Continuous
Recording
I or E
Total Monthly Flow (MG)
Monitor & Report
Monthly
Recorded or
Calculated
I or E
BOD, 5-day, (20°C) 2
(April 1 — October 31)
5.0 mg/L
7.5 mg/L
Daily
Composite
I & E
BOD, 5-day, (20°C) 2
(November 1 — March 31)
7.0 mg/L
10.5 mg/L
Daily
Composite
I & E
Total Suspended Solids2
30.0 mg/L
45.0 mg/L
Daily
Composite
I & E
NH3 as N (April 1-October 31)
1.0 mg/L
3.0 mg/L
Daily
Composite
E
NH3 as N (November 1-March
31)
2.0 mg/L
6.0 mg/L
Daily
Composite
E
Dissolved Oxygen3
Daily
Grab
E
pH 4
Daily
Grab
E
Total Residual Chlorines
17.0 pg/L
Daily
Grab
E
Temperature (°C)
Daily
Grab
E
Fecal Coliform
(geometric mean)
200/100 mi
400/100 ml
Daily
Grab
E
TKN
Monitor & Report (mg/L)
Weekly
Composite
E
NO3-N + NO2-N
Monitor & Report (mg/L)
Weekly
Composite
E
Total Nitrogen, TN 6
Monitor & Report (mg/L)
Weekly
Composite
- E
TN Load 7'8
Monitor & Report (Ib/mo)
334,705 lb/yr (until 12/31/2015)
185,345 lb/yr (effective 1/1/2016)
Monthly
Annually
Annually
Calculated
E
Total Phosphorus, TP
Monitor & Report (mg/L)
Weekly
Composite
E
TP Load 7'8
Monitor & Report (Ib/mo)
14,053 lb/yr
Monthly
Annually
Calculated
E
Total Mercury 9
Annual Average: 12 ng/L
Quarterly
Grab
E
Total Zinc
Quarterly
Composite
E
Chronic Toxicity 1°
Quarterly
Composite
E
Annual Pollutant Scan11
Annually
See A (5)
E
Footnotes are shown on the next page.

Permit No. NC0047597
Footnotes to Table A (1) on the previous page:
1 I = Influent; E = Effluent. See Condition A (2) for instream monitoring requirements.
2. The monthly average effluent BOD5 and Total Suspended Solids concentrations shall not exceed 15% of the
respective influent value (85% removal).
3. The daily average dissolved oxygen effluent concentration shall not be less than 6.0 mg/L.
4. The pH shall not be less than 6.0 standard units nor greater than 9.0 standard units.
. 5. Monitoring requirement and limit applies only if chlorine is added.for.disinfection. The Division shall consider
all effluent TRC values reported below 50 pg/L to be in compliance with the permit. However, the Permittee
shall continue to record and submit all values reported by a North Carolina certified laboratory (including field
certified), even if these values fall below 50 pg/L.
6. TN = TKN + NO3-N + NO2-N, where TN is total nitrogen, TKN is Total Kjeldahl Nitrogen, and NO3-N and NO2-
N are Nitrate and Nitrite Nitrogen, respectively.
7. TN or TP Load is the mass quantity of Total Nitrogen and Total Phosphorus discharged in a given period of
time. See Special Condition A (8) Calculations of Total Nitrogen or Total Phosphorus Loads.
8. Compliance with mass limits shall be determined in accordance with Special Condition A (7), Annual Limits
for Total Nitrogen or Total Phosphorus.
9. Total mercury shall be limited to an annual average of 12 nglL. All sampling must be done using low-level
Method 1631 E.
10. Chronic Toxicity (Ceriodaphnia) P/F @ 90%; January, April, July, and October (See A (4) Special Conditions
of the Supplement to Effluent Limitations).
11. See Special Condition A (5) Effluent Pollutant Scan.
There shall be no discharge of floating solids or foam in other than trace amounts.
A (2) INSTREAM MONITORING REQUIREMENTS
Monitoring Locations: Upstream - New Hope Creek at 1-40
Downstream - At NCSR 1107
Parameter
Frequency
Sample Type
Dissolved Oxygen
3/week, June 1 — September 30; 1/week, October 1 — May 31
. Grab'
Fecal Coliform
3/week, June 1 — September 30; 1/week, October 1— May 31
Grab
Temperature
3/week, June 1— September 30; 1/week, October 1 — May 31
Grab
Conductivity
3/week, June 1 — September 30; 1/week, October 1 — May 31
Grab
pH
3/week, June 1— September 30; 1/week, October 1— May 31
Grab
Total Phosphorus
1/week, June 1— September 30
Grab
NO3-N + NO2-N
1/week, June 1— September 30
Grab
TKN
1/week, June 1— September 30
Grab
PO4
1/week, June 1— September 30
Grab
A (3) PROVISIONAL WAIVER OF INSTREAM MONITORING REQUIREMENTS
Instream monitoring requirements in A (2) above shall be provisionally waived so long as the Permittee
remains a member of the Upper Cape Fear River Basin Association and the Association continues to
function as approved by the Division and Environmental Management Commission. If the Permittee
does not participate in the Association or if the Association ceases to function, the instream monitoring
requirements in this permit become effective immediately; and the Division may reopen this permit by
administrative letter to establish additional instream monitoring requirements it deems necessary to
adequately characterize the effects of the discharges on water quality in the receiving stream.

Permit No. NC0047597
A (4) CHRONIC TOXICITY PASS/FAIL PERMIT LIMIT
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
January, April, July, and October. Effluent sampling for this testing 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 -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:
NCDENR/ 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.
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.

Permit No. NC0047597
A (5) EFFLUENT POLLUTANT SCAN
The Permittee shall perform an annual Effluent Pollutant Scan for all parameters listed in the attached
table. The analytical methods shall be in accordance with 40 CFR Part 136 and shall be sufficiently
sensitive to determine whether parameters are present in concentrations greater than applicable
standards and criteria. Samples shall represent seasonal variations. Unless otherwise indicated,
metals shall be analyzed as "total recoverable."
Ammonia (as N) Trans-1,2-dichloroethylene Bis (2-chloroethyl) ether
Chlorine (total residual, TRC) 1,1-dichloroethylene Bis (2-chlbroisopropyl) ether
Dissolved oxygen 1,2-dichloropropane Bis (2-ethylhexyl) phthalate
Nitrate/Nitrite 1,3-dichloropropylene 4-bromophenyl phenyl ether
Kjeldahl nitrogen Ethylbenzene Butyl benzyl phthalate
Oil and grease Methyl bromide 2-chloronaphthalene
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-octyl phthalate
Arsenic Toluene Dibenzo(a,h)anthracene
Beryllium 1,1,1-trichloroethane 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 Hexachlorocyclo-pentadiene
Acrolein Phenol Hexachloroethane
Acrylonitrile 2,4,6-trichlorophenol Indeno(1,2,3-cd)pyrene
Benzene Base -neutral compounds: Isophorone
Bromoform Acenaphthene Naphthalene
Carbon tetrachloride Acenaphthylene Nitrobenzene
Chlorobenzene Anthracene N-nitrosodi-n-propylamine
Chlorodibromomethane Benzidine N-nitrosodimethylamine
Chloroethane Benzo(a)anthracene N-nitrosodiphenylamine
2-chloroethylvinyl ether Benzo(a)pyrene Phenanthrene
Chloroform 3,4 benzofluoranthene Pyrene
Dichlorobromomethane Benzo(ghi)perylene 1,2,4-trichlorobenzene
1,1-dichloroethane Benzo(k)fluoranthene
1,2-dichloroethane Bis (2-chloroethoxy) methane
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. The report shall be submitted to the following address:
NCDENR/ DWQ/ Central Files
1617 Mail Service Center
Raleigh, North Carolina 27699-1617
* Mercury samples shall be analyzed using EPA Method 1631.

Permit No. NC0047597
A (6) NUTRIENT ALLOCATIONS
(a) The following table lists the Total Nitrogen (TN) and Total Phosphorus (TP) allocations
assigned to, acquired by, or transferred to the Permittee in accordance with the Jordan Lake
nutrient management rule (T15A NCAC 02B .0270) and the status of each as of permit
issuance. For compliance purposes, this table does not supersede any TN or TP limit
established elsewhere in this permit or in the NPDES permit of a compliance association of
which the Permittee is a Co-Permittee Member.
Total Nitrogen Allocation
ALLOCATION
TYPE
. `SOU_ RCE
"DATE
ALLOCATION AMOUNT (1)
'. .. ' ' ... '''
STATUS
° ' ! " �`.
Delivered (Ib/yr)
r
Discharge (Ib/yr) .
Base
Assigned by Rule
(T15A NCAC 02B
.0270)
8/11/09
139,009
185,345
Active
TOTAL
139,009
185,345
Active
Footnote:
(1) Nitrogen Transport Factor = 75%
Total Phosphorus Allocation
t �. ii•�f }:
:,-1
:T' P .
TYPE .
j ' + .:' } ::,
` SOURCE
.i:i ACT,
DA 'EY
:� ALLOCATION' AIIIIOUNT. (') �r
r -
r •.
• STATUs
r.. j
Delivered (Iblyr) •
r
Discharge (Iblyrj
Base
Assigned by Rule
(T15A NCAC 02B
.0270)
8/11/09
9,415
14,053
Active
TOTAL
9,415
14,053
Active
Footnote:
(1) Phosphorus Transport Factor = 67%
(b) Any addition, deletion, or modification of the listed allocation(s) (other than to correct
typographical errors) or any change in status of any of the listed allocations shall be
considered a major modification of this permit and shall be subject to the public review
process afforded such modifications under state and federal rules.

Permit No. NC0047597 •
A (7) ANNUAL LIMITS FOR TOTAL NITROGEN OR TOTAL PHOSPHORUS
(a) Total Nitrogen (TN) and Total Phosphorus (TP) allocations and Toad limits for NPDES
dischargers in the.Jordan Lake watershed are annual limits and apply on a calendar year basis.
(b) For any given calendar year, the Permittee shall be in compliance with the annual TN (or TP)
Load limit in this Permit if:
(i) the Permittee's annual TN (or TP) Load is less than or equal to the effective limit, or
(ii) the Permittee is a Co-Permittee Member of a compliance association.
The TN (or TP) Load limit in this Permit may be modified as the result of allowable changes in
the Permittee's allocations.
(i) Allowable changes include those resulting from purchase of TN (or TP) allocation from
an authorized mitigation banker, the Ecosystem Enhancement Program, or other source
allowed under applicable regulations; purchase, sale, trade, or lease of allocation
between the Permittee and other dischargers; regionalization; and other transactions
approved by the Division.
(ii) The Permittee may request a modification of the TN (or TP) Load limit in this Permit to
reflect allowable changes in its allocation(s).
(A) Upon receipt of timely and proper application, the Division will modify the permit as
appropriate and in accordance with state and federal program requirements.
(B) Changes in TN (or TP) limits become effective on January 1 of the year following
permit modification. The Division must receive application no later than August 31 for
changes proposed for the following calendar year.
(iii) Any requests for modification should be sent to:
NCDENR/ DWQ/ NPDES Programs
Attn: Jordan Lake Watershed Coordinator
1617 Mail Service Center
Raleigh, NC 27699-1617
(d) If the Permittee is a member and co-permittee of an approved compliance association on
January 1 of a given year, its TN and TP discharges during that year are governed by that
association's group NPDES permit and the limits therein.
(i) The Permittee shall be considered a Co-Permittee Member for any given calendar year
in which it is identified as such in Appendix A of the association's group NPDES permit.
(ii) Association roster(s) and members' TN and TP allocations will be updated annually and
in accordance with state and federal program requirements.
(iii) If the Permittee intends to join or leave a compliance association, the Division must be
notified of the proposed action in accordance with the procedures defined in the
association's NPDES permit.
(A) Upon receipt of timely and proper notification, the Division will modify the permit as
appropriate and in accordance with state and federal program requirements.
(B) Membership changes in a compliance association become effective on January 1 of
the year following modification of the association's permit.
(e) The TN and TP monitoring and reporting requirements in this Permit remain in effect throughout
the term of the Permit and are not affected by the Permittee's membership in a compliance •
association.

Permit No. NC0047597
A (8) CALCULATION OF TOTAL NITROGEN OR TOTAL PHOSPHORUS LOADS
(a) The Permittee shall calculate monthly and annual TN Loads as follows:
(i) Monthly TN (or TP) Load (Ib/mo) = TN (or TP) x TMF x 8.34
where:
TN or TP = the average Total Nitrogen or Total Phosphorus concentration
(mg/L) of the composite samples collected during the month
TMF = the Total Monthly Flow of wastewater discharged during the
month (MG/mo)
8.34 = conversion factor, from (mg/L x MG) to pounds
(ii) Annual TN (or TP) Load (Ib/yr) = Sum of the 12 Monthly TN (or TP) Loads for the
calendar year
(b) The Permittee shall report monthly Total Nitrogen and Total Phosphorus results (mg/L and
Ib/mo) in the appropriate discharge monitoring report for each month and shall report each
calendar year's results (Ib/yr) with the December report for that year.
A (9) NUTRIENT MONITORING REOPENER
Pursuant to N.C. General Statute Section 143-215.1 and the implementing rules found in Title 15A of
the North Carolina Administrative Code, Subchapter 2H, specifically, 15A NCAC 2H.0112(b) (1) and
2H.0114(a), and Part II, Sections B-12 and B-13 of this permit, the Director of DWQ may reopen this
permit to require supplemental nutrient monitoring of the discharge. The additional monitoring will be to
support water quality modeling efforts within the Cape Fear River Basin, and shall be consistent with a
monitoring plan developed jointly by the Division and affected stakeholders.
A (10) MERCURY MINIMIZATION PLAN (MMP)
The permittee shall develop and implement a mercury minimization plan during this permit term.
Guidelines for MMP development will be placed on the Division website following a stakeholder review
process. The MMP should place emphasis on identification of mercury contributors and goals for
mercury reduction. Results shall be summarized and submitted with the next permit renewal
application. The MMP must be kept available for inspection on -site.

REASONABLE POTENTIAL ANALYSIS
Mercury
Date Data BDL=1/2DL Results
1 3/5/2008 0.801 0.801 Std Dev. 4.0816
2 4/22/2009 0.679 0.679 Mean 3.4770
3 4/14/2010 1.29 1.29 C.V. 1.1739
4 n 20
5 1/15/2007 1.25
6 4/16/2007 1.72
7 7/16/2007 1
8 1/2/2008 . 18.3
9 4/1/2008 2.97
10 7/1/2008 < 1
11 10/1/2008 1.11
12 1/1/2009 . 4.38
13 4/1/2009 4.21
14 7/1/2009 8.15
15 10/1/2009 4.88
16 1/1/2010 6.19
17 4/1/2010 . 4.82
18 7/1/2010 2.39
19 10/1/2010 2.7
20 1/1/2011 1.7
21 4/1/2011 < 1
22
24
25
26
27
28
29 30 V / I e ('()
31
32
33
34
35
36
37
38
39
40
41
42
USE ONLY
"PASTE
SPECIAL -
Values" WITH
"COPY"
1.25
1.72 Mult Factor =
1 Max. Value
18.3 Max. Pred Cw
2.97
0.5
1.11
4.38
4.21
8.15
4.88
6.19
4.82
2.39
2.7
1.7
0.5
4.06
18.3 ng/L
74.3 ng/L
1
2
3
4
5
Molybdenum
Date Data BDL=1/2DL
3/5/2008 6.7 6.7
4/22/2009 1.3 1.3
4/14/2010 >43 3.13
3/13/2011 2.5, 2.5
Results
Std Dev.
Mean
C.V.
n
USE ONLY
"PASTE
SPECIAL -
Values" WITH
"COPY"
2.3262
3.1929
0.7285
24
6 1/15/2007 < 5 \ 2.5 Mult Factor = 2.48
7 4/16/2007 < 5 2.5 Max. Value 13.0 ug/L
8 7/16/2007 < 5 '2 5 Max. Pred Cw 32.2 ug/L
9
10 1/15/2007 13 13
11 4/16/2007 5 5
12 7/16/2007 < 5 2.5
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
A (t0 W4i b k r13 CenCen-11-476, oh -
1 /1 /2008 < 5 2.5
4/1/2008 < 5 2.5
7/1/2008 < 5 2.5
10/1/2008 < 5 2.5
1/1/2009 < 5 2.5
4/1/2009 < 5 2.5
7/1/2009 < 5 2.5
10/1/2009 : < 5 2.5
1/1/2010 < 5 2.5
4/1/2010 < 5 2.5
7/1/2010 < 5 2.5
10/1/2010 < 5 2.5
1/1/2011 < 5 2.5
4/1/2011 < 5 2.5
Peten4 DGA_ 6 0- 20/1-- cu t/. 20)2
Aki5a�►fn . vat 'S4wpie re.fv1i 1• 67 vI/L
r4&-x (wcvN( S4 p(e %2e.v ( = 3-68 log fL (o cr c )
No T13EL. opiatr b(e- (#& l- ? [7 n5/L
M
I�i urahm New RPA, data
1 7/20/2011
c(ed-,� a eve 14J /L

DURHAM
1869
CITY OF MEDICINE
* * **
CITY OF DURHAM
DEPARTMENT OF WATER MANAGEMENT
101 CITY HALL PLAZA • DURHAM, NC 27701
919-560-4381 • FAX [phone]
November 5, 2012
Gil Vinzani
NPDES Program
1617 Mail Service Center
Raleigh, North Carolina 27699-1617
Administration
919-560-4381
Customer Billing Services
919-560-4412
Laboratory Services
919-560-4386
Plant Maintenance
919-560-4388
Regulatory Compliance
919-560-4381
Utility Engineering
919-560-4381
Wastewater Treatment
North - 919- 560-4384
South - 919-560-4386
Water Supply & Treatment
WiI!iamc - Q1Q-SFr1-434R
-.3 r -
—'U
NOV 7 2012
DENR ✓ATE
POINT SOURCE BRANCH
BRAi JCH
The City of Durham wishes to petition for a reduction of monitoring for effluent total
mercury at the South Durham Water Reclamation Facility, NC0047597. Monitoring
frequency is currently once per month and this request is for a reduction to quarterly
monitoring. This request is allowed by the terms in our permit. Laboratory results
for 13 consecutive months of sampling are attached. All of the results are under the
water quality standard of 12 ng/L. If you have any questions, please call me at 919-
560-4386.
Sincerely,
Charles Cocker
Superintendent
Attachment
1/0 3
(7; - m, f t/il 0 4
Ate
s4-tehl 11'
Mot./ /K""()
Annaofr. l o
a „th,
AMP re
vtrsl+t'.4 14.1
n }
rf1
Durham — Where Great Things Happen

South Durham Water Reclamation Facility
NC0047597 Effluent Low Level Mercury
Sample date Result
October 10, 2011
November 1, 2011
December 1, 2011
January 9, 2012
February 2, 2012
March 5, 2012
April 16, 2012
May 7, 2012
May 22, 2012
June 5, 2012
July 9, 2012
August 6, 2012
September 4, 2012
October 8, 2012
poi-131 i v Z
3.88 ng/L
<1.00 ng/L
<1.00 ng/L
<1.00 ng/L
<1.00 ng/L
1.80 ng/L
<1.00 ng/L
1.16 ng/L
<1.00 ng/L
1.37 ng/L
2.09 ng/L
1.72 ng/L
<1.00 ng/L
<1.00 ng/I
!.5