NC0047384_Permit Modification_19980225

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:
DEN R
February 25, 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. This letter replaces the correspondence
sent to you February 11, 1998, after a typographical error was corrected and language in both the cover letter
and effluent page specifying when new limits become effective was clarified. The following changes are
incorporated upon operation of the aeration tanks and clarifiers specified in this modification:
• Permitted flow is 22.0 MGD instead of 20.0 MGD.
• BOD monthly average (summer) is 10.0 mg/1, weekly average is 15.0 mg/l.
• BOD monthly average (winter) is 20.0 mg/1, weekly average is 30.0 mgfl.
• Ammonia limits are 2.7 mg/1 (summer) and 5.4 mg/I (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/l (10 ppb) as of March 1, 1998 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 after the Effluent Limitations pages permitting 20.0 MGD. Limits for flow at 22.0 MGD will
be effective when aeration tanks 9 through 12 and final clarifiers 5 and 6 are placed into service. Effluent
pages for flow at 30.0 MGD and 40.0 MGD specify the new cyanide quantitation limit, and the old effluent
sheets for these flows 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,
fj,\X. 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

A. (1). EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS FINAL
Permit No. NC0047384
During the period beginning March 1, 1998 and lasting until aeration tanks 9 through 12 and clarifiers 5 and 6 are placed into service, 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:
EFFLUENT CHARACTERISTICS
LIMITS
MONITORING REQUIREMENTS
Monthly
Average
Weekly
Average
Daily
Maximum
Measurement
Frequency
Sample
Type
Sample
Location'
Flow
20.0 MGD
Continuous
Recording
I or E
BOD, 5 day, 20°C (April 1 - October 31)2
. 11.0 mg/I
16.5 mg/1
Daily
Composite
E,
BOD, 5 day, 20°C (November 1 - March 31)2
22.0 mg/I
33.0 mg/I
Daily
Composite
E,
Total Suspended Solids2
30.0 mg/I
45.0 mg/I
Daily
Composite
E, I
NH3 as N (April 1 - October 31)
3.0 mg/1
Daily
Composite
E
NH3 as N (November 1 - March 31)
6.0 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/I
20 µg/I
Weekly
Composite
E
Cadmium
2.1 µg/l
5.0 µg/l
Weekly'
Composite .
E, U, D1
Copper
2/Month
Composite
E
Zinc
2/Month
Composite
E
Cyanides
5.3 µg/1
21..2 µg/1
Weekly
Grab
E
Fluoride
1.9 mg/1
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.
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 not be less than 5.0 mg/I.
4 The pH shall not be less than 6.0 standard units nor greater than 9.0 standard units.
5 Total Phosphorous compliance shallbbe based upon a quarterly average of weekly samples.
6 The quantitation limit for cyanide shall be 10 µg/1 (10 ppb). Levels reported as "<10 µg/1" shall be considered zero for compliance purposes.
7 Chronic Toxicity (Ceriodaphnia) 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.

A. (2). EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS FINAL
Permit No. NC0047384
During the period beginning upon placing aeration tanks 9 through -Wand clarifiers 5 and 6 into service, 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:
EFFLUENT CHARACTERISTICS
LIMITS
MONITORING REQUIREMENTS
Monthly
Average
Weekly
Average
Daily
Maximum
Measurement
Frequency
Sample
Type
Sample
Location'
Flow
22.0 MGD
Continuous
Recording
I or E
BOD, 5 day, 20°C (April 1 - October 31)2
10.0 mg/I
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/I
Daily
Composite
E, I
Total Suspended Solids2
30.0 mg/I
45.0 mg/1
Daily
Composite
E,
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/I
20 µg/I
Weekly
Composite
E
Cadmium .
2.1 µg/I
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/I
Weekly
Grab
E
Fluoride
1.9 mg/I
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.
' 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 not be less than 5.0 mg/I.
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 101.41 (10 ppb). Levels reported as "<10 µg/1" shall be considered zero for compliance purposes.
7 Chronic Toxicity (Ceriodaphnia) 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.

A. (3). EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS FINAL
Permit No. NC0047384
During the period beginning after expansion to 30.0 MGD and lasting until construction to expand to 40.0 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:
EFFLUENT CHARACTERISTICS
LIMITS
MONITORING REQUIREMENTS
Monthly
Average
Weekly
Average
Daily
Maximum
Measurement
Frequency
Sample
Type
Sample
Location'
Flow
30.0 MGD
Continuous
Recording
I or E
CBOD, 5 day, 20°C (April 1 - October 31)2
4.0 mg/1
6.0 mg/I
Daily
Composite
E, I
CBOD, 5 day, 20°C (November 1 - March 31)2
8.0 mg/I
12.0 mg/I
Daily
Composite
E, I
Total Suspended Solids2
3 m /I
45.0 mg/1
Daily
Composite
E, I
NH3 as N (April 1 - October 31)
2.0 m
Daily
Composite
E
NH3 as N (November 1 - March 31)
\4.0 mg/I
Daily
Composite
E
Dissolved Oxygen3
Daily1
Grab
E, U, D1, D2
pH4
Daily
Grab
E
Fecal Coliform (geometric mean)
200 / 100 ml
400 / 100 ml
Daily1
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
18 µg/I
. Daily
Grab
E
Selenium
5.2 µg/I
20 µg/I
Weekly
Composite
E
Cadmium
2.1 µg/I
5.0 µg/I
Weekly1
Composite
E, U, D1
Copper
2/Month
Composite
E
Zinc
2/Month
Composite
E
Cyanides
5.2 µg/l
20.8 µg/I
Weekly
Grab
E
Fluoride
1.9 mg/I
Weekly
Composite
E
Conductivity
Weekly1
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.
I 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 CBOD5 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/I.
4 The pH shall not be less than 6.0 standard units nor greater than 9.0 standard units.
s Total Phosphorous compliance shall be based upon a quarterly average of weekly samples.
6 The quantitation limit for cyanide shall be 10 µg/l (10 ppb). Levels reported as "<10 µg/1" shall be considered zero for compliance purposes.
7 Chronic Toxicity (Ceriodaphnia) 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.

A. (4). EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS FINAL
Permit No. NC0047384
During the period beginning after expansion to 40.0 MGD and lasting until expiration, 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:
EFFLUENT CHARACTERISTICS
LIMITS
MONITORING REQUIREMENTS
Monthly
Average
Weekly
Average
Daily
Maximum
Measurement
Frequency
Sample
Type
Sample
Location'
Flow
40.0 MGD
Continuous
Recording
I or E
CBOD, 5 day, 20°C (April 1 - October 31)2
4.0 mg/I
6.0 mg/I
Daily
Composite
E, I
CBOD, 5 day, 20°C (November 1 - March 31)2
8.0 mg/I
12.0 mg/I
Daily
Composite
E, I
Total Suspended Solids2
30 m /i
45.0 mg/I
Daily
Composite
E, I
NH3 as N (April 1 - October 31)
2.0 mg
Daily
Composite
E
NH3 as N (November 1 - March 31)
4.0 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
18 µg/l
Daily
Grab
E
Selenium
5.2 µg/I
20 µg/I
Weekly
Composite
E
Cadmium
2.1 µg/I
5.0 µg/l
Weekly'
Composite
E, U, D1
Copper •
2/Month
Composite
E
Zinc
2/Month
Composite
E
Cyanides •
5.2 µg/l
20.8 µg/I
Weekly
Grab
E
Fluoride
1.9 mg/I
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.
' 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 CBOD5 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/I.
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 µg/i (10 ppb). Levels reported as "<10 µg/I" shall be considered zero for compliance purposes.
7 Chronic Toxicity (Ceriodaphnia) 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.