NC0047384_Permit Modification_19980211

State of North Carolina
Department of Environment
and Natural Resources
Division of Water Quality
James B. Hunt, Jr., Governor
Wayne McDevitt, Secretary
A. Preston Howard, Jr., P.E., Director
Mr. Arthur White
City of Greensboro
2350 Huffine Mill Road
McLeansville, North Carolina 27301
Dear Mr. White:
A��
DEN R
February 11, 1998
Subject: NPDES Permit Modification
Permit No. NC0047384
T. Z. Osborne WWTP
Guilford County
A permit modification request was received by the Division on December 29, 1997. After review of the
request, the modification to your NPDES permit has been approved. The following changes are incorporated:
• Permitted flow is now 22.0 MGD instead of 20.0 MGD.
• BOD monthly average (summer) is now 10.0 mg/l, daily maximum is 15.0 mg/l.
• BOD monthly average (winter) is now 20.0 mg/l, daily maximum is 30.0 mg/l.
• Ammonia limits are now 2.7 mg/1 (summer) and 5.4 mg/1 (winter).
In light of information available regarding cyanide measurement techniques, the Division feels it is reasonable
to specify the total cyanide quantitation limit as 10 µg/1 (10 ppb) in your NPDES permit. Levels reported as
"<10 µg/1" will be considered zero for compliance purposes.
Please find enclosed the amended Effluent Limitations page for outfall 001 which should be inserted into your
permit upon completion of the upgrade in accordance with the Authorization to Construct (ATC) issued
December 6, 1995. The old effluent sheet for flow at 20 MGD should be discarded. All other terms and
conditions contained in the original permit remain unchanged and in full effect. This permit modification is
issued pursuant to 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 any parts, measurement frequencies, or sampling requirements contained in this permit 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 150B of the North Carolina General Statutes, and filed with the Office of Administrative Hearings,
Post Office Drawer 27447, Raleigh, North Carolina 27611-7447. Unless such demand is made, this decision
shall be final and binding.
P.O. Box 29535, Raleigh, North Carolina 27626-0535 Telephone [phone] FAX [phone]
An Equal Opportunity Affirmative Action Employer 50% recycled/ 10% post -consumer paper

If you have any questions regarding this modification to your permit, please contact Bethany Bolt at (919)
733-5083, Ext. 551.
Sincerely,
A/IPLGI'
?Ara64-e/4—
. Preston Howard, Jr., P.E.
cc: Central Files
Winston-Salem Regional Office/Water Quality Section
NPDES Unit
Point Source Compliance Enforcement Unit
Aquatic Toxicology Unit
Technical Assistance and Certification Unit
EPA/Roosevelt Childress

S
A. (1). EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS FINAL
Permit No. NC0047384
During the period beginning on the effective date of the permit and lasting until construction to expand to 30.0 MGD is complete, the Permittee is authorized to
discharge from outfall(s) serial number 001. Such discharges shall be limited and monitored by the Permittee as specified below:
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Location w
Flow
22.0 MGD
Continuous
Recording
I or E
BOD, 5 day, 20°C (April 1 - October 31)2
10.0 mg/l
15.0 mg/I
Daily
Composite
E, I
BOD, 5 day, 20°C (November 1 - March 31)2
20.0 mg/I
30.0 mg/l
Daily
Composite
E, I
_
Total Suspended Solids2
30.0 mg/1
45.0 mg/1
Daily
Composite
E, I ,
NH3 as N (April 1 - October 31)
2.7 mg/I
Daily
Composite
E
NH3 as N (November 1 - March 31)
5.4 mg/I
Daily
Composite
E
Dissolved Oxygen3
Daily'
Grab
E, U, D1, D2
pH4
Daily
Grab
E
Fecal Coliform (geometric mean)
200 / 100 ml
400 / 100 ml
Daily'
Grab
E, U, D1, D2
Temperature °C
Daily'
Grab
E, U, D1, D2
Total Nitrogen (NO2 + NO3 + TKN)
Monthly
Composite
E
Total Phosphorus5
2.0 mg/I
Weekly5
Composite
E
Total Residual Chlorine
Daily
Grab
E
Selenium
5.3 µg/l
20 µg/l
Weekly
Composite
E
Cadmium
2.1 µg/l
5.0 µg/I
Weekly'
Composite
E, U, D1
Copper
2/Month
Composite
E
Zinc
2/Month
Composite
E
Cyanides
5.3 µg/I
21.2 µg/l
Weekly
Grab
E
Fluoride
1.9 mg/l
Weekly
Composite
E
Conductivity
Weekly'
Grab
U, D1, D2 .
Chronic Toxicity?
Quarterly
Composite
E
Notes:
* Sample locations: E - Effluent, I - Influent, U - Upstream at Old US Highway 70, D1 - Downstream at SR 2821 (Harvest Road), D2 - Downstream at Huffine Farm Road.
1 Upstream and Downstream monitoring shall be grab samples and shall be conducted three times per week during the months of June, July, August, and
September, and once per week during the remaining months of the year, except for Cadmium, which shall be monitored monthly.
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 no be less than 5.0 mg/l.
4 The pH shall not be less than 6.0 standard units nor greater than 9.0 standard units.
5 Total Phosphorous compliance shall be based upon a quarterly average of weekly samples.
6 The quantitation limit for cyanide shall be 10.0 µg/l (10 ppb). Levels reported as "<10.0 µg/I" shall be considered zero for compliance purposes.
7 Chronic Toxicity (Ceriodaphnia) P/F at 90%; January, April, July, and October; See Part III, Condition G.
There shall be no discharge of floating solids or visible foam in other than trace amounts.