NC0026051_Speculative Limits_20000707

State of North Carolina
Department of Environment
and Natural Resources
Division of Water Quality
James B. Hunt, Jr., Governor
Bill Holman, Secretary
Kerr T. Stevens, Director
July 7, 2000
Mr. Chuck Hill, Division Manager
County of Durham
120 E. Parrish Street, Law Building, Suite 100
Durham, North Carolina 27701
SPEC 4(�Dvn-r
"(IMF
Aw•�'
�
NCDENR
Subject: Speculative Limits
Durham Triangle WWTP
NPDES Permit Number NCO026051
Durham County
Dear Mr. Hill:
This letter is in response to your request for speculative effluent limits for a proposed expansion
of the Durham Triangle wastewater treatment plant discharge to Northeast Creek in the Cape Fear River
Basin. This speculative limit request was for an expansion from a 6 to a 12 MGD discharge of treated
municipal wastewater to the creek. The discharge point on Northeast Creek has a drainage area of
approximately 18 square miles, with an estimated summer 7Q10 flow of zero cfs and a positive 30Q2
flow of 0.9 cfs. From the proposed discharge point, Northeast Creek flows south-westerly until it enters
B. Everett Jordan Reservoir.
Based on the available information, speculative limits for the proposed discharge point are
presented in the table below:
Parameter :
Speculative Effluent Limits
(Monthly Average)
Flow, MGD
12
BOD5, mg/L
Summer:
Winter:
5.0
10
Ammonia, mg/L N113-N
Summer:
Winter:
1.0
1.8
Total suspended solids, m
30
Fecal coliform bacteria, or s/100mL
200
Total residual chlorine, m
17
H
6-9
Total phosphorus, annual TP mass load (lbs/ ear)
10,204
Total nitrogen, monthly TN mass load (lbs/month)
8,371
= OO
'At 12 MGD, a 10,204 pound annual TP load corresponds to an average monthly concentration of 0.28 mg/L.
' At 12 MGD, an 8,371 pounds/month TN mass load corresponds to an average monthly concentration of 2.75 mg/L.
1617 MAIL SERVICE CENTER, RALEIGH, NORTH CAROLINA 27699.1617 Telephone [phone]
An Equal Opportunity Affirmative Action Employer 50% recycled / 10% post -consumer paper
Q 4YV

Durham County
Speculative Limits
Page 2
Under the current Division policy, dechlorination and chlorine limits are now required for all
new or expanding dischargers proposing the use of chlorine for disinfection. An alternate form of
disinfection, such as ultraviolet radiation, would allow the facility to comply with fecal coliform limits
without the use of chlorine.
The speculative limits presented here are based on our understanding of the proposal and of
present environmental conditions. These speculative limits are not binding unless they become part of an
issued NPDES permit. Response to a speculative limit request does not guarantee that the Division will
issue Durham County an NPDES permit to discharge treated wastewater into waters of the State. Nor
can we guarantee that the effluent limitations and other requirements included in any permit will be
exactly as presented here. As you are aware, House Bill 515 (HB515) and Senate Bill 1366 (SB 1366)
provisions for nutrient sensitive waters affect Northeast Creek. As mandated by HB515 and SB 1366, a
nutrient response model is under development for Jordan Reservoir and major tributaries. The modeling
results will likely affect permit limits of all NPDES permit holders in the Jordan Reservoir watershed.
Any speculative limits presented in this letter may increase or decrease as a result of the modeling. I urge
you to contact Michelle Woolfolk of our staff to stay informed of potential permitting strategies for the
watershed. She may be reached at [phone] extension 505.
In accordance with the North Carolina General Statutes, the practicable waste treatment and
disposal alternative with the least adverse impact on the environment must be implemented. Non -
discharge alternatives, such as spray irrigation, connection to a regional wastewater treatment facility, or
reuse options, are considered to be environmentally preferable to a discharge. Therefore, prior to
submittal of an NPDES major modification request, a detailed alternatives analysis must be prepared to
assure that the environmentally sound alternative was selected from the reasonably cost-effective options.
A guidance document to assist you or your consultant in preparing an engineering alternatives analysis
(EAA) is enclosed.
It should be noted that an expansion of more than 0.5 MGD for an existing facility will require
that an environmental document be prepared by the applicant. The North Carolina Environmental Policy
Act and its associated rules require that an Environmental Assessment (EA) and Finding of No
Significant Impact (FONSI) be prepared before the permit for expansion is issued. If deemed
appropriate, there is a possibility that an environmental impact statement (EIS) might be necessary.
All information pertaining to this request has been sent to our Central Files and NPDES files for
storage. If it becomes necessary to request an NPDES facility expansion (considered a major
modification), please submit a complete application package including the appropriate fees. If you have
any additional questions about these limits or the NPDES application process, please contact Tom
Belnick at [phone], extension 543.
Sincerely,
�
David A. Goodrich
Supervisor, NPDES Unit
Water Quality Section
cc: Raleigh Regional Office
Central Files
NPDES Unit

Stec /M// /e we i l
...cwa°�'.
nr....
COUNTY OF DURHAM
ENGINEERING DEPARTMENT
May 17, 2000
Mr. Dave Goodrich
NPDES Unit Supervisor
NCDENR Division of Water Quality
1617 Mail Service Center
Raleigh, NC 27699-1617
I lAAY 2 2 2000
POINT- WATER QUALITY
SOURCE BRAE 11
Re: Triangle Wastewater Treatment Facility Expansion — Durham County, NC
Dear Mr. Goodrich:
Durham County has initiated the project referenced above both to improve treatment
capability and to increase the capacity of the County owned wastewater treatment plant.
As consultants hired by Durham County, McKim & Creed has scheduled a meeting with
you on May 22, 2000 at 10:30 AM to discuss speculative effluent limitations. We know
how busy you are, and sincerely appreciate the efforts you are taking to work with us on
this extremely important project.
As you are aware, the Research Triangle Park is a vitally important economic resource to
Durham County. We are committed to providing both the current operations and the
planning necessary to support the wastewater treatment needs within the Durham County
portion of the Research Triangle Park. As a part of this planning process, we have
completed a study to use as a guide to complete upgrades to treatment capability and
increased capacity needs. These upgrades are critical to comply with the implementation
of recent regulations for Nitrogen removal, and to prepare for continuing increases in
flow based on our latest projections.
It is in this light that we are requesting your cooperation and assistance in working with
us to expedite sound technical solutions for expanding the Triangle WWTF, without
creating undue environmental impacts. We understand that the first step in this process
will be to establish permissible effluent limits for the upgraded WWTF (i.e. speculative
limits). These limits are necessary to finalize the Basis of Design Report, submit the
NPDES Permit Amendment, and respond to review comments on the previously
submitted Environmental Assessment.
120 E. Parrish Street, Law Bldg., 1st Floor, Durham, N.C. 27701 [phone] Fax [phone]
Equal Employment/Affirmative Action Employer

D. Goodrich
May 17, 2000
Page 2
Thank you in advance for your cooperation.
Sincerely,
14 a
Chuck Hill, P.E.
Utility Division Manager
cc: Glen E. Whisler, P.E., County Engineer
Bryan Blake, McKim & Creed

Northeast Creek/New Hope Arm of Jordan Reservoir (CPF)
Prepared for meeting with Durham Triangle WWTP representatives 5/22/2000.
Northeast Creek Water Quality:
• Northeast Creek from Hwy 55 to 0.5 miles downstream of Panther Creek is 303(d) listed for fecal
coliform bacteria.
• DMR monthly average fecal coliform bacteria levels in effluent generally remain less than
200/100mL based on geometric means from January 1998 to March 2000.
• Based on summer 1999 data, instream DO appears to increase downstream of the W WTP.
Lake Water Quality:
• DWQ monitors the New Hope Creek arm of Jordan Reservoir at CPF081AIC and CPF086F (below
the confluence with Morgan Creek). Chlorophyll -a levels at both stations have exceeded the water
quality standard of 40 µg/L between 1993 and 1999.
• AGPT are not available for Segment 4 of the lake (planned for 2000). Previous AGPTs from 1985
through 1996 indicate the lake may be limited by N, P, co -limited, or not limited, depending on the
time and location. AGPTs in Northeast Creek from 1989 indicate N or co -limiting conditions.
Chlorophyll -a, New Hope Creek Arm Jordan Lake
(086F)
120
0 100
80 —
c 5 60 -
0 ' 40 - — -
V 20 . t
0
1993 1994 1995 1996 1997 1998 1999
Year
120
100
c 80
60
• 40
u
0 20
V 0
High Low • Average
New Hope Creek Arm (081A1C)
1993 1994 1995 1996 1997 1998 1999
Year
t
0

H8515 and SB1366:
(see copies)
Monthly Avg. TN: Durham Triangle W WTP
35 ---
c� 30
O 35
E
20
a
,5
g
� ,9
5
b
5"47 Jarv90 Apr -ea Ju590 Nov-90 Fab-99 MayA9 Au9.99 Doc-W Mar-00 Ju O
Dab
BB515 mandates concentrations* of 5.5 mg/L TN in effluent. Monthly average effluent DMR data
indicates this has not been achieved.
Monthly Avg. TP: Durham Triangle W WTP
4.5
a
{ 3.5
€
s
ad
P
1.5
1
0.5
0
9ap-97 JanAa Apr-95 JoW Nov-90 Fab-09 Nay-99 Aug-90 Dao-90 Mor-0 JumW
Dab
• BB515 mandates concentrations* of 2 mg/L TP in effluent. Generally, this has been achieved.
Facility has summer permit Hurt of 0.5 mg/L TP and winter limit of 2 mg/L.
• Annual 1999 TP load was 12,7861bs.
a R t -RR , a IL wr �If
Jordan Nutrient Response Modeling pv1�
Y--r 0
• Modeling undertaken by 7 local permit holders and a consultant. Modeling anticipated to be
complete in December 2001. Permitted nutrient loads for all facilities in the watershed may be
revised based on model results.
• A time -variable nutrient response model will be completed using currently available data and
additional 2000/2001 data collected by DWQ and others. Optional modeling work may include fate
and transport modeling along major tributaries. s

July 7, 2000
v MCIQM&CREED
v
M&C 1471-0002 (10)
Mr. Dave Goodrich ------ --
NPDES Unit Supervisor [ j
NCDENR Division of Water Quality
1617 Mail Service Center
Raleigh, NC 27699-1617 JUL
� I
RE: Triangle Wastewater Treatment Facility Expansion
Durham County, NC POINT
- WATER QUALITY
(\IG(. C�i�' ( POINT SOURCE BR,4N":i
Dear Mr. Goodrich,
Please find enclosed a copy of the minutes from our May 22nd meeting. Please distribute as
needed within your department.
As you are aware, the County is anticipating your letter addressing speculative limits the first
week of July. We appreciate your time and assistance with Durham County's request.
Sincerely,
McKIM & CREED, P.A.
Bryan F. Blake, P.E.
Project Manager
/der
Enclosure
cc: Chuck Hill, P.E., Durham County
Glen Whistler, P.E., Durham County
Kevin C. Eberle, P.E., McKim & Creed
Tim Baldwin, P.E., McKim & Creed
a \1471=02M\07o 0G..dn.n.d«
5625 DILLARD DR., SUITE 117, CARY, NORTH CAROLINA 27511
TEL [phone] FAX [phone] www.mckimcreed.com
AA0002667

MEETING NOTES
PREPARED BY McKIM & CREED
DURHAM COUNTY
TRIANGLE WASTEWATER TREATMENT PLANT
MEETING WITH DENR, DWO
MAY 22, 2000
Attendees:
Chuck Hill, Durham County
Timothy J. Baldwin, P.E., McKim & Creed
�ryan F. Blake, P.E., McKim & Creed
Kevin Eberle, P.E., McKim & Creed
Dave Goodrich, DWQ — NPDES Unit
Tom Belnick, DWQ — NPDES Unit
Ken Schuster, DWQ — Raleigh Regional Office
Michelle Woolfolk, DWQ — Modeling Unit
• Chuck opened with introduction and historical overview.
• Kevin followed with review of flow projections and schedule/timing.
• Dave raised questions on the extent of any 1/1 evaluations or work.
• Chuck relayed efforts of the 6/98 flow metering study which identified three major
outfalls: one with no great apparent problems; one which was mostly under
County control and has received some repairs, largely inflow/topside related; and
one which is mostly under City control and the County notified the City to
implement some form of rehabilitation. The County has budgeted funds for a
second round of year -long metering project to reevaluate current status and also
create baseline data for more effective cost allocation. After considerable
discussion Dave reiterated that the 1/1 documentation needs to be in the EA and
they will continue to emphasize flow reduction.
• Moved into discussion of speculative limits, water quality considerations.
Michelle related modeling inflow and water quality considerations in Northeast
Creek/New Hope arm of Jordan reservoir and handed out some data showing
elevated Chlorophyll A levels and relayed concern over non -supporting
conditions.
Dave stated that House Bill 515 imposed nitrogen limits of 5.5 mg/I based on the
1996 permitted flow capacity. This mass limit would be allocated on a monthly
average basis. They have somewhat more flexibility in the allocation of the
phosphorus limits, but they feel that they could not support any discharge
allocation in excess of actual waste load at the current time (i.e., based on 4.2
MGD; 12,786 Ibs/yr).
• Dave encouraged evaluation of reuse opportunities (despite acknowledgement
average monthly mass limitations do not favor instituting reuse to the extent that
annual mass limitations would).
• Dave also queried and encouraged careful evaluation of regionalization with the
City of Durham. It is clear that they want to see this carefully evaluated, although
acknowledged that non -technical issues often are constrained and take a long
time to resolve.
• Dave and Michelle discussed the nutrient response model underway by the
seven municipal partners scheduled for completion as December 2001. It is
p:V 471\0002\00\05220Notes.dw v MCIQM & CREED

Meeting Notes
May 22, 2000
Page 2
anybody's guess what the results of that model may be. They may demonstrate
either the need for even more strict limits or the ability to relax certain parameters
(as is obviously the hope of some of the participants). In any event, it is apparent
that the results of that study will not be available until well after some decisions
must be made and progress made regarding the design and possibly the
construction of this facility.
Dave committed to formulate speculative discharge limits and provide them to
the County in the form of a letter prior to July 4, 2000.
We indicated that our schedule called for completion of the EAA and EA within
the next three to four weeks. However, this work is dependent on the speculative
limits approved by the Department.
091471W002W0\05220Notes.dw 46
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TRIANGLE WASTEWATER TREATMENT PLANT
05/01/2000
FY2000
FY2001
FY2002
CURRENT FLOW MGD
4.2
PERMITTED FLOW GPD
240,639
534,090
133.150
UNDER REVIEW GPD
0
291,204
436,806
PLANNED GPD
0
60,000
140,000
TOTAL PROJECTED GPD
240,639
885,294
709,956
TOTALS MGD
4.44
6.33
6.04

RECEIVED
Ans'd............
The
MEMORANDUM
Company Wooten
To:
Chuck Hill
From:
Ford Chambliss
Engineering
Date:
November 24, 1997
Planning
Re:
Status Report
Architecture The North Carolina Division of Water Quality has still not responded to our request for
speculative limits regarding increased discharges, nor have they responded until today to
our request for any suggestions they might have regarding alternative discharge point
locations. The reason given for the delay (the requests are months old) is that they are
1 trying to determine the impact of legislation passed this summer on permitting requirements
upstream of Jordan Lake. We are hesitate to project a completion date for a draft report
/without knowing when the State will release any speculative limits. Assuming we have
something concrete from the State within the next 2 weeks, a draft report being delivered in
120 N. Baylan Avenue late January or early February is possible. This is later than what we had discussed in
Raleigh, NC October, but in October we expected to have the information from the State in the early part
gran of November.
On the wastewater reuse portion of the study, target potential major reusers have been
' identified and a follow up questionnaire targeted for those reusers is being prepared. We
expect to be contacting you the week of December 1 regarding setting a time and place for
919•828-OM1 meeting with potential industrial reuse customers.
We have a meeting scheduled with the City of Durham on December 3, 1997 to go over
force main routes and other details of alternatives involving using the City of Durham's
wastewater treatment plants.
Mr. Jason Doll with the North Carolina Division of Water Quality Modeling Section did
give Mr. Eric Mills with our staff an opinion regarding alternative discharge point locations
during a telephone conversation today. Mr. Doll felt that the discharge should not be
located any closer to Jordan Lake than its present location, nor should it be located any
further upstream than its present location. Mr. Doll said that since the City of Durham
discharges into the New Hope Creek Basin he did not feel that that Basin was appropriate
to consider for a discharge point location. Finally, Mr. Doll did not feel considering the
present status of the Neuse River that any consideration of relocating the discharge into that
Basin would be appropriate. In summary, while the NC-DWQ does not like the present
discharge point location, they are unable to suggest any alternative points that they fell
would be better.
The lack of a viable location for an alternative discharge point will simplify the
Environment Assessment portion of the study. We had hoped that the NC-DWQ would
Since 1936 have released their new guidelines for EA's by now, but the Divisions's recent
reorganization has delayed this document. We will proceed under the old guidelines.
We have not yet taken any significant steps on the sludge handling portion of the study,
pending the receipt of speculative limits from the State and the better establishment of
design flows, which in turn will allow long term sludge handling need projections to be
completed.

Northeast Creek/New Hope Arm of 3ordan Reservoir (CPF)
Prepared for meeting with Durham Triangle WWTP representatives 5/22/2000.
Northeast Creek Water Quality:
• Northeast Creek from Hwy 55 to 0.5 miles downstream of Panther Creek is 303(d) listed for fecal
coliform bacteria.
• DMR monthly average fecal coliform bacteria levels in effluent generally remain less than
200/100mL based on geometric means from January 1998 to March 2000.
• Based on summer 1999 data, instream DO appears to increase downstream of the W WTP.
Lake Water Quality:
DWQ monitors the New Hope Creek arm of Jordan Reservoir at CPF081AIC and CPF086F (below
the confluence with Morgan Creek). Chlorophyll -a levels at both stations have exceeded the water
quality standard of 40 µg/L between 1993 and 1999.
AGPT are not available for Segment 4 of the lake (planned for 2000). Previous AGPTs from 1985
through 1996 indicate the lake may be limited by N, P, co -limited, or not limited, depending on the
time and location. AGPTs in Northeast Creek from 1989 indicate N or co -limiting conditions.
Chlorophyll -a, New Hope Creek Arm Jordan Lake
(086F)
20
CF 0 100 -- —
80 -
60
c•i ° 40-
c
0 20-
0
1993 1994 1995 1996 1997 1998 1999
Year
High Low . Average
New Hope Creek Arm (081A1C)
120
100
0 80
60
m 40
r
0 20
01 i I
1993 1994 1995 1996 1997 1998 1999
Year

HB515 and SB1366:
(see copies)
Monthly Avg. TN: Durham Triangle W WTP
35
30
19 25
E
e 20
S 15
L
:o
5
0
Sep-py Jan-99 brvBe JUL9a Nav-09 Fa9-99 Nay-W Au9-a9 Dec -BB Mar-00 Jur00
Dab
BB515 mandates concentrations* of 5.5 mg/L TN in effluent. Monthly average effluent DMR data
indicates this has not been achieved.
Monthly Avg. TP: Durham Triangle WWTP
4.5
a
3.5
3
2.5
L3
8 2
a
,
B.5
0
9ap47 Jan-99 Apr-99 JUL99 Nov-99 Fa0-H May-99 Aug-99 Doo-99 Marv00 Jun-00
Dab
BB515 mandates concentrations* of 2 mg/L TP in effluent. Generally, this has been achieved.
Facility has summer permit limt of 0.5 mg/L TP and winter limit of 2 mg/L.
Annual 1999 TP load was 12,7861bs.
Jordan Nutrient Response Modeling
• Modeling undertaken by 7 local permit holders and a consultant. Modeling anticipated to be
complete in December 2001. Permitted nutrient loads for all facilities in the watershed may be
revised based on model results.
• A time -variable nutrient response model will be completed using currently available data and
additional 2000/2001 data collected by DWQ and others. Optional modeling work may include fate
and transport modeling along major tributaries.

BioDenipho Process
at
Cary, NC
Month
Ave. Flow
MGD
Temp
°c
BOD (mgll)
TSS (mg/1)
NH3 (mg/1)
TP (mg/1)
NOz out
TKN (mg/1)
TN (mg/1)
In
Out
In
Out
In
Out
(mg/1)
In
Out
Out
Jul 97
226
0.9
298
0.04
7.0
1.6
3.3
41
1.3
4.6
Aug 97
266
1.8
350
0.04
7.2
0.8
1.4
40
0.9
2.5
Sept 97
4.6
271
0.8
352
$2.732.1
0.04
7.7
0.7
1.9
34
1.2
3.0
Oct 97
4.9
280
0.7
385
0.04
7.8
0.8
1.1
41
1.0
2.1
Nov 97
5.1
285
1.2
328
0.07
6.6
1.8
1.3
46
1.3
2.6
Dec 97
5.1
295
1.1
329
0.05
7.1
0.3
1.0
46
1.3
2.2
Averagel
4.9
1
1 271
1.1
340
1.7
31.1
0.05
7.2
1.0
1.7
1 41
1 1.2
2.8
Jan 98
6.6
15.4
262
1.7
328
1.9
27.3
0.05
6.0
0.3
1.4
42
1.4
2.7
Feb 98
6.7
14.8
227
1.6
342
1.7
24.9
0.09
6.0
0.4
1.1
43
1.3
2.5
Mar 98
6.9
15.3
221
2.2
275
1.5
26.4
0.29
6.3
0.3
0.8
41
1.3
2.1
Apr 98
5.9
18.4
264
2.3
297
1.4
30.6
0,60
6.9
0.2
1.2
43
1.5
2.6
May 98
5.7
20.8
292
1.6
378
1.4
30.2
0.08
6.9
0.4
0.4
45
1.3
1.7
Jun 98
5.7
23.7
264
2.0
339
2.4
33.6
0.18
7.3
0.8
0.3
49
1.2
1.6
Jul 98
5.5
25.6
275
1.5
345
1.1
34.4
0.03
7.3
0.3
0.4
36
1.0
1.3
Aug 98
5.7
26.0
295
1.0
391
1.1
29.5
0.03
7.9
0.2
0.6
46
1 1.0
1.5
Sept 98
5.6
26.0
307
1.3
335
1.1
3
7.0
0.3WO.447
0.9
1.3
Oct 98
5.5
24.0
298
1.4
374
1.6
7.4
0.251
1.0
1.3
Nov 98
5.4
21.7
317
1.5
381
1.0
7.6
0.750
Dec 98
5.4
19.8
336
1.4
392
1.3
j32A.40.03
7.3
0.151
1.3
1.7
Average
5.9
20.9
280
1.6
348
1.4
7.0
0.3
0.7
45
1.2
1.9
Jan 99
6.2
16.5
321
2.5
395
1.5
1 28.2
0.04
1 6.5
0.6
0.6
41
1.6
2.2
Feb 99
5.8
16.6
228
2.1
291
3.0
30.2
0.30
1 7.0
0.7
0.6
44
2.2
2.7
Mar 99
6.2
16.1
200
2.3
274
6.0
31.5
0.07
6.8
0.5
1.5
57
3.9
5.3
Apr 99
6.1
18.7
242
2.1
307
1.5
35.5
0.03
7.2
0.4
64
1.7
2.0
May 99
5.8
21.1
241
2.0
357
1.1
37.6
0.03
7.9
0.3
80
4.0
4.3
Jun 99
5.7
23.7
235
2.0
379
1.3
40.4
0.06
7.8
0.5
53
2.9
3.1
JU1991
5.8
25.4
224
2.0
304
1.1
36.3
0.03
7.1
0.2
50
2.8
3.2
Aug 99
5.9
26.8 1
216
2.0
344
1.1
39.9
0.03
7.9
0.2
48
1.0
1.3
Sept 99
8.1
24.2
182
2.6
312
1.2
30.3
0.03
6.6
0.2
1.0
46
1.9
2.7
Oct 99
5.9
22.5
202
2.0
286
1.1
34.8
0.03
7.2
0.2
0.7
38
1.2
1.8
Nov 99
5.3
201
2.0
329
1.0
43.9
0.07
7.7
0.2
56
1.2
2.2
Dec 99
Average
6.1
21.2
226
2.1
325 1
1.8
35.3
0.07
7.2
0.4
0.9
53
2.2
2.8
PAPerformance Data\Cary, NC\Performance Data\Monthly Data Summary.xis

2000 Performance Data
Cary, NC
Date
Flow
MGD
Temp
°C
BOD mg/I
I TSS mg/I
NI-13 mg/I
TP mg/I
NOx out
TKN mg/I
TN mg/I
In
lout
lin
Out
In
Out
In
lout
mg/I
In
Out
Out
02/01/2000
7.2
13
108
2.0
184
1.2
25.1
0.03
4.71
0.1
30.6
1.1
3.0
02/02/2000
7.3
13
119
2.0
180
1.0
37.4
0.03
5.41
0.1
35.4
1.0
2.4
02/03/2000
7.0
13
212
2.0
260
1.0
38.0
0.03
5.91
0.1
43.9
1.2
2.9
02/04/2000
7.4
13
185
2.0
308
1.0
36.9
0.05
02/05/2000
6.81
14
02/06/2000
7.0
13
02/07/2000
6.6
13
181
2.0
308
1.0
27.8
0.03
6.3
0.1
38.6
1.3
2.2
02/08/2000
6.3
14
121
2.0
490
1.0
26.7
0.03
6.9
0.1
52.8
1.2
2.2
02/09/2000
6.2
14
176
2.0
324
1.0
33.8
0.03
7.0
0.1
42.8
1.3
1.5
02/10/2000
6.3
15
177
2.0
246
1.0
33.6
0.03
02/11/2000
6.2
15
208
2.0
320
1.1
46.1
0.46
02/12/2000
7.1
15
02/13/2000
7.0
14
02/14/2000
7.2
15
153
2.0
144
1.0
28.6
0.03
5.1
0.4
66.8
1.1
2.1
02/15/2000
6.6
15
1941
2.01
248
1.0
33.5
0.03
6.5
0.2
56.8
0.9
1.7
02/16/2000
6.6
15
1951
2.01
304
1.0
33.9
0.03
6.1
0.2
68.1
1.2
2.2
02/17/2000
5.9
15
1921
2.01
412
1.1
50.2
0.51
02/18/2000
7.1
16
201
2.01
316
1.0
39.3
0.29
02/19/2000
6.6
15
02/20/2000
6.4
15
02/21/2000
6.1
15
215
2.0
268
1.9
40.5
0.27
6.5
0.3
j 57.6
1.0
2.2
02/22/2000
6.0
15
231
2.0
332
1.0
29.2
0.03
6.9
0.3
63.0
1.3
2.2
02/23/2000
5.6
15
237
2.0
316
1.0
34.6
0.03
7.3
0.3
52.8
1.2
2.1
02/24/2000
6.0
15
216
2.0
376
1.5
37.6
0.03
02/25/2000
5.8
16
230
2.0
428
1.6
37.2
0.03
02/26/2000
5.7
16
02/27/2000
6.1
17
02/28/2000
6.2
16
201
2.0
268
1.4
33.8
0.07
6.7
0.3
56.8
2.6
3.0
02/29/2000
6.2
16
178
2.0
292
0.0
33.8
0.03
6.5
0.3
52.5g2.9
.9
3.4
Average =
6.5
15
187
2.0
301
1.1
35.1
0.1
6.2
0.2
#DIV/OI
51.3.4
2.4
Max =
7.4
17
237
2.0
490
1.9
50.2
0.5
7.3
0.4
0.0
68.1
3.4Min
=
5.6
13
108
2.0
144
0.0
25.1
0.0
4.7
0.1
0.0
30.6.9
1.5
PAPerformance DatalCary, NC\2000 Performance Data.xls

2000 Performance Data
Cary, NC
Date
Flow
MGD
Temp
°C
BOD mg/I
TSS mg/I
NIi3 mg/I
TP mg/l
NOx out
TKN mg/I
TN mg/I
In
Out
In
Out
In
Out
In
Out
mg/1
In
Out
Out
03/01/2000
6.2
16
268
2.0
372
1.7
39.5
0.03
52.5
2.4
2.9
03/02/2000
5.2
16
203
2.0
342
1.0
39.9
0.03
03/03/2000
5.6
17
196
2.0
304
1.2
42.2
0.03
03/04/2000
5.9
16
03/05/2000
5.7
16
03/06/2000
5.6
16
222
2.81
304
1.0
37.7
0.03
7.5
0.2
52.41
1.2
1.8
03/07/2000
6.1
17
198
2.01
338
1.0
37.3
0.03
9.11
0.2
52.2
1.1
1.7
03/08/2000
6.6
17
240
2.0
484
1.3
36.9
0.03
8.01
0.2
54.9
1.1
2.1
03/09/2000
5.8
18
202
2.0
308
1.0
37.6
0.03
03/10/2000
5.4
18
200
2.0
388
1.0
41.3
0.03
03/11/2000
5.6
18
03/12/2000
5.5
17
03/13/2000
5.4
17
252
2.1
270
1.0
38.7
0.03
7.8
0.2
52.6
1.1
1.5
03/14/2000
5.4
17
252
2.0
406
1.0
40.1
0.03
8.6
0.4
55.3
1.3
1.7
03/15/2000
5.9
17
248
2.0
328
1.0
38.6
0.03
7.8
0.2
53.1
1.2
1.7
03/16/2000
6.3
18
245
2.0
388
1.0
33.6
0.03
03/17/2000
5.8
18
246
2.0
384
1.0
38.2
0.03
03/18/2000
5.6
18
0.03
03/19/2000
5.7
17
03/20/2000
6.3
17
228
2.0
406
1.1
34.4
0.03
7.71
0.2
52.2
1.21
1.9
03/21/2000
5.9
17
233
2.0
302
1.5
31.3
0.03
8.1
0.2
46.9
1.2
1.8
03/22/2000
5.8
17
263
2.0
340
1.1
35.2
0.03
7.7
0.2
48.2
1.1
1.8
03/23/2000
5.8
17
259
2.0
372
1.4
49.5
0.03
03/24/2000
5.7
18
207
2.0
318
1.7
38.6
0.03
03/25/2000
5.7
18
03/26/2000
5.6
18
03/27/2000
6.2
18
227
2.0
324
1.5
33.8
0.03
7.1
0.3
50.3
1.1
1.6
03/28/2000
6.2
18
182
2.0
290
1.1
35.3
0.03
7.31
0.2
47.3
1.0
1.6
03/29/2000
6.3
17
183
2.0
294
1.1
31.4
0.03
6.7
0.2
46.8
1.0
1.6
03/30/2000
5.9
18
230
2.0
302
1.3
36.1
0.03
03/31/2000
5.2
18
190
2.0
360
1.0
37.5
0.03
Average =
5.80
17
225
2.0
345
1.2
37.6
0.0
7.8
0.2
51.1
1.2
1.8
Max =
6.64
18
268
2.8
484
1.7
4 ..5
0.0
9.1
0.4
55.3
2.4
2.9
Min =
5.16
16
182
2.0
270
1.0
31.3
0.0
6.7
0.21
1
46.8
PAPerformance Data\Cary, NC\2000 Performance Data.xls

TABLE
DURHAM COUNTY TRIANGLE WWTF SERVICE AREA
SEWAGE FLOW PROJECTIONS
FROM 2000 TO 2020
YEAR
RESIDENTIAL
SEWAGE FLOW (1)
(GPD)
INSTITUTIONAL
SEWAGE FLOW (2)1
(GPD)
COMMERCIAL
SEWAGE FLOW (3)
(GPD)
INDUSTRIAL
SEWAGE FLOW (4)
(GPD)
INDUSTRIAL PROCESS
WASTEWATER FLOW (5)
(GPD)
FUTURE INFILTRATION
ALLOWANCE 6)
(GPD)
PREDICTED AVERAGE DAILY
SEWAGE FLOW TO THE
TRIANGLE WWTF (GPD)
2000
1,357,912
149,864
2.349,009
657,402
-
-
4,514,187
2005
1,863.471
205,349
2.812,741
752,796
1,556,328
269,068
7,459,753
2010
2,486,044
273,676
3,177,219
844,244
3,048,271
532,945
10,362,399
2015
2.794,426
307.520
3,295,080
872,442
3,508,308
627,778
11,405,553
t2O2tO2,907,244
320,854
3,360,334
889,248
3,782,500
676,018
11,936,198
NOTES:
1) Residential Sewage Flows based on Residential Dwelling Unit predictions taken from the Durham -Chapel Hill-Carrboro Metropolitan Planning Organization 2025 Comprehensive
Transportation Plan and associated Socio-Emnomic Forecast published in 1999. This comprehensive planning document was accepted by all 14 of the MPO member agencies via
resolution of the Board on August 12, 1999,
2) For the purpose of this analysis, the number of Institutional users is expected to increase at the same rate as residential growth. Sewage Bow from Institutional users was predicted
based on the current average daily sewage production of 2.882 gpd per Institutional User.
3) Commerical sewage Bows are based on predicted commercial job growth as published in the DCHC 2025 Transportation Plan and the existing sewage production rate of 57 gpd per
commercial job. Existing sewage production rates are based on metered water usage.
4) Industnal sewage Bows are based on predicted industrial job growth as published in the DCHC 2025 Transportation Plan and the existing sewage production rate of 32 gpd per
industrial job. Existing sewage production rates are based on metered water usage.
5) An allowance for process wastewater generated from future "water -using" industries was computed based on the following assumptions: 1) Remaining undeveloped, industrial -zoned
property within the Triangle WWTF Senior Area is 2,375 acres (Year 2000 data from GIS database), 2) 75% (or 1,780 acres) of the total undeveloped, indusMel-zoned property will be
developed for industrial uses by 2025, 3) Of the developed acreage, 11 BB acres will be developed with "lighr water -using industries and will produce process sewage Bows of only
1,000 gpd/acre on average; 4) The remaining 592 acres will be developed with "heavy" water -using industries and will produce process sewage Bows of approximately 5,000 gpd/acre
(an average).
6) Since B was not possible to accurately predict future infiltration contributions, a 10%allowance for infiltration was made based on projected new flows only.

iCl
0/.
G
(9
3: 10
O
J
U.
x
W
Q 8
Lu
W
N
N
Q
6
}
J
Q
w 4
O
Lu
w
Q
6
80% of Design �
Capacity (4.8 MGD)
0+-
1995
DURHAM COUNTY TRIANGLE WASTEWATER TREATMENT FACILITY
WASTEWATER FLOW PROJECTIONS
2000
Proposed Design Flow = 12 MGD
Projected Date For Reaching 100% of Design Capacity (6 MGD) = October
2002
2005
2010
YEAR
2015
2020
2025

TRIANGLE WASTEWATER TREATMENT FACILITY
PREDICTION OF FUTURE WASTEWATER FLOW (2000 TO 2020)
12,000,000
10,000,000
0 8,000,000
a
C7
O
LL 6,000,000
w
0
a
ul
w
cn 4.000,00(
2,000,001
YEAR 2015 2020
0Institutional Flow N Industrial Flow ® Industrial Process Wastewater Flow Mommerciel Flow A Residential Flow © Infiltration Allowance Motal Sewage Flow
5/22/00 FlowSummaryGraphsBBW.xIs

900,001
500,00
400,00
300,00
200,00
100,00
TRIANGLE WASTEWATER TREATMENT FACILITY
EXISTING PERMITTED LOADING
(PoundsNear)
CBOD TSS TN NH3-N TP
B WE
mCurrently Permitted Loading @ 6 MGD
t) Current Permitted Loading based on seasonal limits; BOD = 5 mgA 810 mgA; TSS = 30 mi TN based on current averaoe effluent concert of 15.3 mW (no NPDES limit); NH3-N = 1.0 mgrl 8 1.8 mgA; TP = 0.5 mgA 8 2.0 mgA
LA-e77- LY (�rj)

A. O. EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS WINTER (November 1 - March 31) Permit No. NC0026051
During die period beginning on tic effective date of the permit and lasting until expiration, the Permittee is authorized to discharge from
oulfall(s) serial number(X)I. Such discharges shall be limited and monitored by the permittee as specified below:
ElllLien I Characleriot lc
Flow
BOD, 5 day, 20°C"
Total Suspended Residue"
NH3 as N
Dissolved Oxygen"'
Fecal Colilorm (geometric mean)
Total Residual Chlorine
Temperature
Total Nitrogen (NO2 + NO3 + TKN)
Total Phosphorus
Chronic Toxicity""'
Monthly Ava
6.0 F"
10.0 mg/l
30.0 mg/I
1.8 mg/I
200.0 1100 ml
2.0 mg/I""
Weekly Avg.
15.0 mg/l
45.0 mg/1
400.0 /100 ml
anti
Measurement sample
Dally Me x Frequency Type
Continuous Recording
Deily Composite
Dally
Deily
Dolly
Daily
Dolly
Daily
Monthly
Weekly
Quarterly
Composite
Composite
Grab
Grab
Grab
Grab
Composite
Composite
Composite
'Sample
Location
IorE
E, I
E, I
E
Fr, U, D
E. U. D
E
E,U,D
E
E
E
*Sample locations: E - Effluent, I - Influent, U - Upstream at NCSR 1102, D - Downstream at (1) NCSR 1100 and (2) NCSR 1732
Upslrcam and downstream samples shall be grab samples. Stream samples shall be collected three times per week during June, July, August,
and September and once per week during the remaining months of the year.
**The monthly average effluent BOD5 and Total Suspended Residue concentrations shall not exceed 15 % of the respective influent value (85
%) removal.
*** The daily average dissolved oxygen effluent concentration shall not be less than 6.0 mg/I.
**** Compliance shall be based on a quarterly average of weekly samples.
***** Chronic Toxicity (Ceriodaphnia) PIF at 90%; February, May, August and November; See Part III, Condition G.
+ Limits take effect April 1, 1997. Monitoring only 2/mondt required prior to that date.
Ifthe first daily samples for nickel, lead, cyanide, and mercury are in compliance with the weekly averages for those parameters, the rest of the
daily samples do not need to be analyzed. If the limits are not met at first, then the rest of the daily samples should be analyzed and reported.
The pi I shall not be less than 6.0 standard units nor greater than 9.0 standard units and shall be monitored daily at the effluent by grab sample.
There shall be no discharge of ❑oaring solids or visible foam in other than trace amounts.

A. O. EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS SUMMER (April 1 - October 31) Permit No. NC0026051
During die period beginning on the effective dale of the permit and lasting until expiration, the Permiltce is authorized to discharge from
outfall(s) serial number WI. Such discharges shall be limited and monitored by the permittee as specified below:
Effluent Cherecteriatl
Flow
BOD, 5 day, 20°C"
Total Suspended Residue"
NH3 as N
Dissolved Oxygen"'
Fecal Colilorm (geometric mean)
Total Residual Chlorine
Temperature
Total Nitrogen (NO2 + NO3 + TKN)
Total Phosphorus
Chronic Toxicity'**"
Monthly Avc
6.0 MGD
5.0 mg/1
30.0 mg/I
1.0 mg/I
200.0 /100 ml
0.5 mg/I'•'•
Weekly Avg.
7.5 mg/1
45.0 mg/I
400.0 1100 ml
Monlloring_
HegiMlrementr
Measurement
sam
•SA—m-P�e
Deily Me x Frequency
Tyge
Locallon
Continuous
Recording
I or E
Daily
Composite
E, I
Daily
Composite
E.I
Daily
Composite
E
Daily
Grab
E, U. D ..
Daily
Grab
E. U. D
Daily
Grab
E
Daily
Grab
E,U,D
Monthly
Composite
E
Weekly
Composite
E
Quarterly
Composite
E
*Sample locations: E- Effluent, I -influent, U -Upstream at NCSR 1102, D- Downstream at (I) NCSR 1100 and (2) NCSR 1732
Upstream and downstream samples shall be grab samples. Stream samples shall be collected for temperature, dissolved oxygen, feel
coliform, and conductivity duce times per week during June, July, August, and September and once per week during the remaining months of
the year. All other stream sampling shall be conducted during June, July, August, and September only.
**The monthly average effluent BOD5 and Total Suspended Residue concentrations shall not exceed 15 % of the respective influent value (R5
%) removal.
*** The daily average dissolved oxygen effluent concentration shall not be less than 6.0 mg/I.
**** Compliance shall be based on a quarterly average of weekly samples.
***** Chronic Toxicity (Ceriodaphnia) P/F at 90%; February, May, August and November; See Part III, Condition G.
+ Limits take effect April 1, 1997. Monitoring only 2/month required prior to that dale.
If the first daily samples for nickel, lead, cyanide, and mercury are in compliance with the weekly averages for those parameters, tire rest of die
daily samples do not need to be analyzed. If the limits are not met at first, then the rest of the daily samples should be analyzed and reported.
The piI shall not be less than 6.0 standard units nor greater than 9.0 standard units and shall be monitored daily at the effluent by grab sample.
There shall be no discharge of floating solids or visible foam in other than trace amounts.

v MCIQM&CREED
v
April 6, 2000 M&C 1471.0002 (10)
Mr. Dave Goodrich
NPDES Unit Supervisor
NCDENR Division of Water Quality
1617 Mail Service Center
Raleigh, NC 27699-1617
RE: Request for Project Initiation Meeting
Triangle Wastewater Treatment Facility Expansion
Durham County, NC
McKim & Creed Project # 1471.0002
Dear Mr. Goodrich,
McKim & Creed, P.A. has recently been retained by Durham County to assist them with
permitting and design of an upgrade to their existing Triangle Wastewater Treatment Facility
(NPDES Permit #NC0026051). Prior to commencing work on the project, however, we would
like to schedule a project initiation meeting with you and your staff to discuss water quality and
permitting issues.
Based on our prior conversations with Mark Mcintire of your staff, we understand that you would
like to delay this meeting for approximately two weeks to allow you sufficient time to review the
project and discuss issues internally. With this in mind, we would like to schedule the meeting
for Monday, April 24T" or Tuesday April 25T" in your office. We believe this initial meeting is
vitally important. Therefore, we appreciate your special efforts to work with us early -on to
develop a mutually acceptable solution for the Durham County, Triangle WWTF.
We have prepared the following project overview to assist you in understanding some of the
most significant issues:
The Wooten Company completed an Engineering Evaluation of the facility in 1997-1998
and issued a Preliminary Engineering Report in June 1998. The most significant
findings included:
Preliminary treatment units and influent pumping station are not adequately
protected from flooding and lack sufficient capacity to accommodate peak, wet —
weather flows. This is evidenced by periodic flooding from the pump station.
O%1471W002110W -ODGoo In d ,/
5625 DILLARD DR., SUITE 117, CARY, NORTH CAROLINA 27811
TEL[phone] FAx[phone] www.mckimcreed.com

Mr. Dave Goodrich
417/00
Page 2
• Tertiary filters and effluent flow meter are periodically flooded due to backwater from
Northeast Creek.
• The existing chlorine disinfection process results in the production of
trihalomethanes, (specifically bromodichloromethane and dibromodichloromethane)
at levels which periodically exceed current NPDES limitations.
• The biosolids treatment, storage and handling processes are inadequate to
accommodate current and future needs.
• The existing facility periodically experiences problems in meeting minimum effluent
dissolved oxygen concentrations prior to discharge.
• Flows to the existing Triangle WWTF are approaching 80% of the permitted design
capacity and recent population and job creation models indicate that sewage flows to
the facility are expected to double by 2020.
Recommendations to address these issues included:
Construct a new, higher capacity, headworks and influent pumping station to
eliminate existing problems associated with flooding.
❖ Construct a new UV disinfection system to replace the existing chlorine disinfection
system (and eliminate the associated production of trihalomethanes).
In conjunction with the UV disinfection system, construct a new effluent pumping
station and cascade aeration process. These improvements would be designed to
meet effluent dissolved oxygen limitations as well as to prevent backwater from
impacting the upstream tertiary filtration and effluent flow metering processes.
Construct a new three -stage biological nutrient removal process with additional
capacity to accommodate 2020 design flows from the Service Area.
2. Mc Kim & Creed was retained by Durham County to evaluate alternatives for handling
existing and future flows to the Triangle WWTF. The September 1999 report considered the
following three alternatives:
Maintain existing Triangle WWTF at 6 MGD and pump the excess flow into the City
of Durham's wastewater collection and treatment system.
Abandon the Triangle WWTF and pump the entire flow to the City of Durham.
Upgrade the existing WWTF (with a five -stage biological nutrient removal process in
light of impending limitations contained in HB 515) and expand the hydraulic and
organic capacity to correct existing deficiencies and to accommodate current and
2020 design flows from the Triangle Sewer Service Area.
0%14]11000211004-06[gGO ri C
L M�IQM C _ED

Mr. Dave Goodrich
4/7/00
Page 3
Based on projected annual cost, an upgrade of the Triangle WWTF (with five -stage
biological nutrient removal and expanded hydraulic capacity) to meet more stringent
effluent limitations will be significantly less costly than either of the other two options.
3. McKim & Creed will also be evaluating biosolids wasting, thickening, dewatering and
disposal alternatives for the Triangle WWTF. This study will be conducted concurrently to
insure the most cost-effective biosolids management program can be incorporated into the
WWTF upgrade.
Please review this information and contact me via phone [phone])or email
(keberle(aDmckimcreed.com) after you have had an opportunity to check your calendar. Thank
you in advance for your input on this project.
Sincerely,
M�cKIM & CRE D, P.A.
Kevin C. Eberle, PE
Senior Engineer
c: Chuck Hill, P.E., Durham County
Glen Whistler, P.E., Durham County
Bryan Blake, P.E., McKim & Creed
Tim Baldwin, P.E., McKim & Creed
Bob Elefritz, P.E., McKim & Creed
0 %1471\000211010/-0600(3oodkRdoc
v�MC
MM&CREED