NC0026051_Application_20130627

COUNTY OF DURHAM
ENGINEERING DEPARTMENT
UTILITY DIVISION
June 27, 2013
Mr. Matt Matthews
NCDENR DWQ Water Quality Section Chief
1617 Mail Service Center
Raleigh, North Carolina 27699-1617
Re: Durham County Triangle WWTP, NPDES Pe
Dear Mr. Matthews,
rmit Amendment Request
I herewith request an administrative permit amendment to remove Condition A.(8.)(c.) of the subject permit
which requires reporting and tracking of nutrients being discharged during atmospheric blowoffs of reuse water
generated by Durham County. The facility began selling reuse water to the Town of Cary in February 2012, and
the Town of Cary has operated the valves which blowoff the reuse water. The amount of nutrients being tracked
is insignificant and do not, in my opinion, justify the administrative burden. A summary of the discharge in
2012/2013, a normalized annual value, and a calculation of the blowoff load/annual load is provided below:
Year
No. of
Months
Total Atmospheric Blowoff
(gallons)
Total Nitrogen Load
(pounds)
Total Phosphorus Load
(pounds)
2012
11
530,160
12.39
1.06
2013
5
501,540
8.54
.3
Total
16
1,031,700
20.93
1.36
Monthly Average
64,481
1.31
0.085
Normalized
Annual Value
773,772
15.72
1.02
Permitted Annual
Load
111,207
8,432
Atmospheric
Blowoff
Load/Permitted
Annual Load (%)
1
0.014%
0.012 %
The administrative burden is created as the Town of Cary must record and transmit all of the flow data to
Durham County, Durham County must correlate these flows with the nutrient loads in the time period, and
generate a custom spreadsheet to transmit this data to NCDENR. NCDENR did not develop a spreadsheet or
format for this data to be submitted, so Durham County had to develop one. I doubt NCDENR-DWQ is entering
this data into any database or using it for any valuable purpose. As the loads from these blowoffs are so very low
(less than 0.015% of the permitted load), this intense tracking system should not be required.
TRIANGLE WASTEWATER TREATMENT PLANT
5926 NC Highway 55 East, Durham, N.C. 27713 • [phone] • Fax [phone]
Equal Employment/Affirmative Action Employer

Additionally, please realize this wastewater treatment plant has one of the very lowest nutrient discharge
concentrations in North Carolina. To my knowledge, it is the only facility at which the Jordan Lake limits have
already been implemented. Our 2005 improvements have been documented to have decreased our small
watershed nutrient load by 64% based on stream data. The specific USGS study is the "Relation of Watershed
Setting and Stream Nutrient Yields at Selected Sites in Central and Eastern North Carolina, 1997-2008" and this
improvement is specifically noted on Page 25. You can access the document at the following link:
http://pubs.usgs.gov/sir/2013/5007/.
If you decide not to remove Condition A.(8.)(c.) from the subject permit, then please let me know the following:
1. Why the same condition is not in all other NPDES permits with conjunctive reclaim water systems?
2. Why the discharge phosphorus loads from potable water blowoffs are not being tracked? (Many potable
water supplies have phosphorus concentrations much higher than Durham County's reclaim water
phosphorus concentration, and please remember the Jordan model shows phosphorus is the limiting
nutrient.)
To assist you with your review, attached is the page from the permit with the condition and the Durham County
reports which have been submitted with the monthly DMR's. I have previously mentioned this issue to your
staff, and they stated they wanted a letter requesting this modification. If you have any questions or need
additional information, please contact me at [phone].
Sincerely,
1P(
Joseph R. Pearce, P.E.
Utility Division Manager/POTW Director
Enclosures
cc: Jon Risgaard, NCDENR Aquifer Protection Section
JRP/cs

Permit No. NC0026051
Monthly TN (or TP) Load (lb/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 (lb/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
lb/mo) in the appropriate discharge monitoring report for each month and shall report each
calendar year's results (lb/yr) with the December report for that year.
(c.) The Permittee shall report monthly volume of water discharged from the blow -off valves and
Total Nitrogen and Total Phosphorus content of the discharge (mg/L and lb/month).
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.) STANDARD CONDITIONS FOR NPDES PERMITS
The Division will provide an updated version of the Standard Conditions for NPDES Permits to the
permittee upon approval of the version by the EPA. Then, the old version shall be replaced with an
updated version.

Non -Sewer Reuse Water Blowoff Report
NPDES #: NC0026051
Facility Name: Triangle Wastewater Treatment Plant
County: Durham
Year: 2012
Month
January
February
March
April
May
June
July
August
September
October
November
December
Total
Durham Blowoff Cary Blowoff Total Blowoff Average TN Average TP TN Load TP Load
(gallons) (gallons) (gallons) (mg/I)
(rn /I) ( d) d
0
0
0
1.83
g
0.25
poun s
0
(poun s)
0
0
44509
44509
2.50
0.20
0.93
0.07
0
27298
27298
2.05
0.22
0.47
0.05
0
0
0
2.91
0.41
0
0
0
54542
54542
3.33
0.35
1.51
0.16
0
61469
61469
3.18
0.43
1.63
0.22
0
54365
54365
2.51
0.60
1.14
0.27
0
2687
2687
2.35
0.28
0.05
0.01
0
39312
39312
3.78
0.39
1.24
0.13
0
119253
119253
3.48
0.09
3.46
0.09
0
56136
56136
1.73
0.06
0.81
0.03
0
70589
70589
1.96
0.05
1.15
0.03
0
530160
530160
12.39
1.06 1
Signature of Operator in Responsible Charge:
Date:

Non -Sewer Reuse Water Blowoff Report
NPDES #: NC0026051
Facility Name: Triangle Wastewater Treatment Plant
County: Durham
Year: 2013
Month
January
February
March
April
May
June
July
August
September
October
November
December
Total
Durham Blowoff Cary Blowoff Total Blowoff Average TN Average TP TN Load TP Load
(gallons)
(gallons) (gallons) (mg/I
me/I
0
106045
106045
2.13
0.08
1.88
0.07
0
138394
138394
2.32
0.06
2.68
0.07
0
90834
90834
2.69
0.07
2.04
0.05
0
77021
77021
1.39
0.10
0.89
0.06
0
89246
89246
1.41
0.06
1.05
0.04
0
501540
501540
8.54
0.30
Signature of Operator in Responsible Charge:-,-.12/-4-,---4--
Date: (0 `;2s - 13