NC0047384_Permit Modification_20080227

AVA
NCDENR
North Carolina Department of Environment and Natural Resources
Division of Water Quality
Michael F. Easley, Governor William G. Ross, Jr., Secretary
Coleen H. Sullins, Director
February 27, 2008
Allan Williams, Director of Water Resources
City of Greensboro
2199 White Street
Greensboro, NC 27405
Subject: Modification of NPDES Permits NC0024325 and NC0047384
North Buffalo WWTP and T.Z. Osborne WWTP
Guilford County
Dear Mr. Williams:
The Division of Water Quality has received and reviewed the Town's minor permit modification requests for
NPDES permits NC0024325 and NC0047384 dated February 12, 2008, for North Buffalo WWTP and T.Z.
Osborne WWTP. In response to your request, the subject NPDES permits have been modified to reflect the
following:
• Footnote 8 within Condition A. (1.) of each permit, has been changed to reflect a quantitation limit
for cyanide at 20 jig/L.
Please find enclosed the revised pages, which should be inserted into each respective permit. The old pages
may then be discarded. All other terms and conditions contained in the original permits remain unchanged
and in full effect. These permit modifications are issued under the requirements of North Carolina General
Statutes 143-215.1 and the Memorandum of Agreement between North Carolina and the U.S.
Environmental Protection Agency.
If you have any questions concerning these permit modifications, please contact Vanessa Manuel of the
Eastern NPDES Program at [phone], extension 532.
Sincerely,
Coleen H. Sullins
cc: DWQ/SWP Central Files
DWQ/SWP Winston-Salem Regional Office
NPDES Unit
1617 Mail Service Center, Raleigh, North Carolina 27699-1617
512 N. Salisbury St., Raleigh, North Carolina 27604
Phone: [phone]! FAX [phone] / Internet: h2o.enr.state.nc.us
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Permit NC0047384
STATE OF NORTH CAROLINA
OF ENVIRONMENT
DEPARTMENT 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, othernl n Sul
Env
standard
s and re� lations promulgated and adopted by the North Carolina amended, the
Management Commission, and the Federal Water Pollution Control Act,
City of Greensboro
is hy ereb authorized to discharge wastewater from a facility located at the
T.Z. Osborne WWTP •
Huffine Mill Road west of McLeansville
Guilford County
to receiving waters designated as South Buffalo Creek in the Cape Fear River Basin in accordance
uirements, and other conditions set forth in Parts I, II and II
with effluent limits, monitoring re q
hereof.
The permit shall become effective March 1, 2008.
This permit and the authorization to discharge shall expire at midnight on June 30, 2011
Signed this day February 27, 2008.
r ; Coleen H. Sullins, Direc or
Division of Water Quality
By Authority of the Environmental Management Commission
1.

Permit NC0047384
A. (1) EFFLUENT LIMITS AND MONITORING REQUIREMENTS — FINAL
Beginning on March 1, 2008, and lasting until June 30, 2011, the permittee is authorized to discharge treated wastewater from
outfall 001. Such discharges shall be limited and monitored by the permittee as specified below:
EFFLUENT
CHARACTERISTICS
EFFLUENT LIMITATIONS
MONITORING REQUIREMENTS
Monthly
Average
Weekly
Average
Daily
Maximum
Measurement
Frequency
Sample
Type
Sample
Location'
Flow
40.0 MGD
Continuous
Recording
Influent or Effluent -
Total Monthly Flow (MG)
Monitor and Report
Monthly
Recorded or
Calculated
Influent or Effluent
CBOD, 5-day, 20°C (Summer)2 •
4.0 mg/L
6.0 mg/L
Daily
Composite
Influent & Effluent
CBOD, 5-day, 20°C (Winter)2
8.0 mg/L
12.0 mg/L
Daily
Composite
Influent & Effluent
Total Suspended Solids2
30.0 mglL
45.0 mg/L
Daily
Composite
_
Influent & Effluent
NH3 as N (Summer)
2.0 mg/L
6.0 mglL
'
Daily
Composite
Effluent
NH3 as N (Winter)
4.0 mglL
12.0 mg/L
Daily
Composite
Effluent
Fecal Coliform (geometric mean)
200/100 mL
400/100mL
Daily
Grab
Effluent
Dissolved Oxygen3
•
-
Daily
Grab
Effluent
Temperature°C
Daily
Grab
Effluent
pH4
Daily
Grab
Effluent 1
Total Nitrogen (NO2+NO3+TKN)5
Weekly
Composite
Effluent
Total Phosphorus6
2.0 mg/L quarterly averages
Weekly
Composite
Effluent
Chronic Toxicity?
Quarterly
Composite
Effluent
Total Cyanide8
5.2 pg/L
22.0 pg/L
Weekly
Grab
Effluent
Total Mercury
0.012 pg/L
Weekly
Grab9
Effluent
Total Copper
2/Month
Composite
Effluent
Total Zinc
2/Month
Composite
Effluent -
Total Nickel*
91.0 pg/L
Weekly
Composite
Effluent
Fluoride*
1.9 mg/L
Weekly
Composite
Effluent
Total Cadmium
2.0 pg/L
Weekly
Composite
Effluent
Total Residual Chlorine
18.0 pg/L
Daily
Grab
Effluent
Dissolved 0xygen1°
10
Grab
U, D1, D2
Fecal Coliform1°
10
Grab
U, D1, D2 .
Temperature°Cui
10
Grab
U, D1, D2
Conductivity1°
10
Grab
U, D1, D2
TKN (mg/L)
Monitor and Report
Weekly
Composite
Effluent
NO3-N + NO2-N (mg/L)
Monitor and Report
Weekly
Composite
Effluent
TN Load""
Monitor and Report (Ib/mo)
Monitor and Report (Ib/yr)
Monthly
Annually
Calculated
Calculated
Effluent
Effluent
TP Load1'
Monitor and Report (Ib/mo)
Monitor and Report (lb/yr)
Monthly
Annually
Calculated
Calculated
Effluent
Effluent
Pollutant Scan
See section A. (5)
Notes:
1. U: Upstream at Old U.S. Highway 70. D1: Downstream at NCSR 2821 (Harvest Road). D2: Downstream at Huffine
Farm Road.

Permit NC0047384
2. The monthly average effluent CBODS and TSS concentrations shall not exceed 15% of the respective influent value
(85% removal).
3. The daily effluent dissolved oxygen 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. TN nutrient limit required by HB 515 is deferred until results of nutrient response modeling effort are completed.
6. Compliance shall be based on a quarterly average of weekly samples, with quarterly periods defined as January -March,
April June, July -September, and October -December.
7. Chronic Toxicity (Ceriodaphnia) at 90% with testing in January, April, July and October (see Special Condition A. (2)).
8. The quantitation limit for cyanide shall be 20 µg/L; levels reported below 20 µg/L shall be considered zero for
compliance purposes.
9. Effluent samples must be analyzed by an EPA -approved low level mercury analysis method.
10. Instream monitoring requirements are waived as long as facility retains membership in the UCFRBA. If membership is
cancelled, facility will monitor 3/Week (June -September) and 1/Week (October -May). Stream sampling may be
discontinued at such times as flow conditions in the receiving waters or extreme weather conditions will result in a
substantial risk of injury or death to persons collecting samples. Upon such discontinuance, stream sampling shall be
resumed at the first opportunity after the risk period has ceased.
(Summer): April 1- October 31, (Winter): November 1 - March 31
(Daily): every day on which a wastewater discharge occurs except Saturdays, Sundays, and legal holidays unless otherwise
specified by the Director.
11. TN or TP Load is the mass quantity of Total Nitrogen or Phosphorus discharged in a given period of time. See Special
Condition A. (4), Calculation of Mass Loads.
* The limit might be removed if the facility submits 12 month of data that shows no reasonable potential to exceed the water
quality standard.
There shall be no discharge of floating solids or visible foam in other than trace amounts.