NC0026051_Historical information_20081231

Michael F. Easley, Governor
January 4, 2008
9 2008
SLEIGH REGIONAL OFFICE
Mr. Vance:
An Equal Opportunity/Affirmative Action Employer - 50% Recycled/10% Post Consumer Paper
cc: Danny Smith, RRO
Meritech, Inc.
Tritest, Inc.
Central Files_____
Please be reminded that if it is the intention of the facility to split toxicity
samples, all elements of the toxicity tests should be the same between the splitting
laboratories. This includes the sampling time. Please contact me at [phone], or
Susan Meadows at [phone] if you have any questions.
Raleigh, NC 27699-1621
Raleigh, NC 27607
William G. Ross Jr., Secretary
North Carolina Department of Environment and Natural Resources
Phone [phone]
FAX [phone]
Coleen H. Sullins, P.E. Director
Division of Water Quality
Mr. Glen Vance
City of Durham
5926 NC Hwy 55 East
Durham, N.C. 27713
Subject: Chronic Toxicity Testing
City of Durham Triangle WWTP
NPDES No. NC0026051
Durham County
CERTIFIED MAIL
RETURN RECEIPT REQUESTED: 7006 0100 0003 8497 2216
/Sincerely,
Cindy A. Moore
Supervisor, Aquatic Toxicology Unit
My staff has received and reviewed the City of Durham’s 10/1/2007 effluent toxicity reports that were
performed by Tritest and Meritech. Upon closer inspection of the Chain-Of-Custody sheets (COC), our office
noted that the first samples were pulled on 10/1/07-10/2/07 @ 1158pm. However, the second samples were
pulled on 10/3/07-10/4/07 for Tritest & 10/6/07-10/07/07 for Meritech. Since the second samples were pulled
on two different days, our office concludes these are two separate test results and not a true split.
These tests were also determined to be invalid because the first samples were started on 9/30/07-10/1/07
(Sunday-Monday) not 10/1/07-10/2/07 as recorded on each labs Chain-of-Custody sheets. Both labs initially
followed the appropriate test renewal procedures, but since the samples were collected a day earlier than
recorded on the COC forms the test renewals for both labs exceeded the 72 hour sample hold time, making
both tests invalid.
North Carolina Division of Water Quality 1621 Mail Service Center
Internet: www.esb.enr.state.nc.us 4401 Reedy Creek Rd.
NorthCarolina_ Naturally
Customer Service
1-877-623-6748
o^& 4^7, £? /fjj I IfA
February 14,2008
HAND-DELIVERED
Re: Sludge Disposal, Triangle TWWTP, Durham County, NC
Dear Mr. Hardee:
If you have any questions or require additional information, please contact me at [phone].
Sincerely,
cc:
JRP/js
,L OFFICEutr
The Durham County Facility disposed of 1366.4 dry tons of sludge in calendar year 2007. The
sludge was dewatered, treated and disposed by Bio-Nomic Services, Inc. Bio-Nomic Services
Inc. transported the sludge to Earthtec of NC, Inc., an NCDENR permitted Class A Composting
facility for stabilization.
Mack Wiggins, NCDENR - RRO
Pete Corsaro, Project Manager - United Water
Glen E. Whisler, P.E., County Engineer
Richard G. Simms, Project Manager
120 E. Parrish Street. Law Bldg., 1st Floor, Durham, N.C. 27701 [phone] Fax [phone]
Equal Employment/Affirmative Action Employer
Ed Hardee
Division of Water Quality - NCDENR
1617 Mail Service Center
Raleigh, NC 27699-1617
COUNTY OF DURHAM
ENGINEERING DEPARTMENT
Teceiive^
i FEB I 5 2008
OU
^Joseph R. Pearce, P.E.
Utility Division Manager
February 28. 2008
Raleigh, NC 27609
Sincerely,
Cc: Joseph Pearce, POTW Director
progress.
If you have any questions, I can be reached by telephone at 919-201-6278.
Mr. Mack Wiggins
NCDENR-DWQ-Raleigh Regional Office
3800 Barrett Drive
Glenn Vance
Operations & Maintenance Manager
ORC
United Water
Triangle Wastewater Treatment Plant
Re: Triangle Wastewater Treatment Plant, Durham County, NC0026051
Dear Mr. Wiggins:
This letter is to inform you of a situation that has developed within the Triangle
Wastewater Treatment Plant. The Biological Nutrient Removal tanks have developed three
small leaks, located in the concrete wall expansion joints. This has resulted in a bypass of the
final clarification process of an estimated volume less than five gallons. That volume has been
trapped within a temporary sump and pumped back into the process.
A repair scope has been developed by the original design engineers, and a request for
quotes is currently underway. Clean up of the tanks in preparation for the repair has begun, as
well as work to mitigate the issue and to minimize any negative impacts to the process.
Please find attached, the repair scope, as well as photographs of the issue.
I will inform you of the status of the repairs as well as any further developments as things
1.SK-S2
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STAGE #3STAGE #2STAGE #1
NORTH
(PLAN)
JOB# 1471-0003
I
I
J
SK-
OXIDATION
TANKS
(TYP.)
EXIST.
CONG.
WALL
BNR BASIN - EXPANSION JOINT BASE SLAB
& WALL REPAIR
E.O. EXIST.
CONC. SLAB
© T.O. WALL
REF. NOTE 3
(TYP. 4 PLCS.)
-1ST ANOXIC
CELL (TYP.)
CN | (/>■
I I * I (/) I
V
in
=1
1 1
1
United Water - Triangle WWTP, Durham Co.
I DATE: 2/22/08
(•)
SK-S1
SHEET 1 OF 3
E.O. EXIST.
CONC.
SLAB ©
T.O. WALL
EJ
1 - PLAN - EXIST. 5 STAGE BNR BASIN
SCALE: l/eA’^l’-O"
^NFKIM&CREED
1730 Varsity Drive, #500, Venture IV Bldg.
Raleigh, North Carolina 27606
Phone:[phone] Fax:[phone]
www.mckimcreed.com
w
4 SEAL
024995
I
ANAEROBIC
CELLS
a-RE-AERATION CELL (TYP.)
/ <"2ND ANOXIC CELL (TYP.)
/ /EJ EJ
/W
o
l F
NOTES:
1. IN GENERAL BNR BASIN IS A C.I.P. REINFORCED CONCRETE. MULTI-CELL OPEN TANK FACILITY.
2. EXPANSION JOINTS (EJ) ARE EXISTING & CONTINUOUS THROUGH THE BASE SLAB, WALLS &.
TOP SLABS (IF APPLICABLE) AS SHOWN.
3. ’>--------1" SYMBOL INDICATES LOCATION OF EXPANSION JOINT REPAIR SYSTEM. IN GENERAL REPAIR
WORK INVOLVES: APPLYING SIKA COMBIFLEX AT l/F OF WALLS AND BASE SLAB; AT 0/F OF
WALLS REMOVING THE EXISTING JOINT SEALANT AND THEN RESEALING THE JOINT. REFERENCE
SECTIONS 8c DETAILS FOR ADDITIONAL INFORMATION.
4. DIMENSIONS <8c CALL-OUTS MARKED AS (♦) ARE APPROXIMATE & REFER TO EXISTING CONSTRUCTION.
Il If
a 1n EXIST. AL
ACCESS
STAIR &
PLATFORM
(TYP. 5
PLCS.)
.....
z
4 *
4
REF. NOTE 4
4
a
«
•
&4
4
REF. NOTE 5
4t4 '
* 4
NOTES:
>
JOS# 1471-0003
O
I
l/F JOINT REPAIR
TO WALLS &
BASE SLAB
REMOVE EXISTING
SEALANT IN IT’S
ENTIRETY FOR
WALLS ic SLAB
(TYP.)
BNR BASIN - EXPANSION JOINT BASE SLAB
& WALL REPAIR
EXTERIOR WALL
OUTSIDE FACE (O/F)
1 - SECTION - EAST EXTERIOR WALL
SCALE:
I’-e”
(*)
United Water - Triangle WWTP, Durham Co.
[ DATE: 2/22/08
2l-0"
(•)
I'-O* (•)
[TYP.]
SK-S2
SHEET 2 OF 3
AT.O. GRADE
VEL O’-6" (♦)
aT.O. CQNC. WALL
VEL 19’-9”(*)
at.q. CQNC. SLAB
Yel 19’-9"O
^REMOVE EXIST. SEALANT IN
/ IT’S ENTIRETY FOR FULL
' HEIGHT OF WALL. FULL
DEPTH TOP SLAB & FULL
WIDTH OF TOP SLAB (T<8cB)
& REPLACE w/ NEW SEALANT
INTERIOR WALL
INTERIOR FACE
(l/F)
EXTERIOR WALL
INTERIOR FACE (l/F)
*
4 A
■XT.O. CQNC./SLAB
yel 0’-0,,O
\ \ 024995 ; =* • •
'"'•<.1.1.11““ **
1. REFERENCE ELEVATION FOR THE BNR BASIN BASE SLAB IS EL O’-O" = EL 250,-3” (250.25) N.A.V.D..
2. REFERENCE CONSTRUCTION SKETCHES SK-S1 & SK-S3 FOR ADDITIONAL NOTES & INFORMATION.
3. AT INTERIOR & EXTERIOR WALLS w/ NO TOP SLAB APPLY JOINT INTERIOR FACE (l/F) REPAIR
SYSTEM FOR FULL HEIGHT OF WALL "UP” TO THE CHAMFER © THE T.O. WALL.
4. AT INTERIOR & EXTERIOR WALLS w/ A TOP SLAB APPLY JOINT l/F REPAIR SYSTEM FOR FULL
HEIGHT OF WALL "UP” TO THE BTM. OF THE TOP SLAB &. T.O. WALL
5. AT l/F OF THE BASE SLAB APPLY JOINT l/F REPAIR SYSTEM FOR FULL LENGTH OF THE JOINT.
6. REFERENCE CONSTRUCTION SKETCH 1.SK-S3 FOR THE l/F & O/F OF WALL EXP. JT. REPAIR SYSTEM.
4§>MZKIM6'CREED
1730 Vorsity Drive. #500. Venture IV Bldg.
Roleigh, North Carolina 27606
Phone:[phone] Fax: [phone]
www.mckimcreed.com
r@ T.O. INTERIOR WALL FROM BTM. E.O.
/ CHAMFER TO BTM. E.O. CHAMFER REPAIR SIM.
/ TO EXTERIOR WALL O/F
j ^REF. NOTE 3
4
IE
EJ WIDTH VARIES
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<3 A
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A A
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-brj
l/F OF CONC.
WALL <8c JT.
4
<]A
<7
POLYEURETHANE
ELASTOMERIC SEALANT
(REF. NOTE 1)
SPLICE/BOND JOINTS IN THE
HYPALON STRIPS PER SIKA’s
"APPLICATION'’
RECOMMENDATIONS
l/F OF CONC.
WALL <Sc JT.
0/F OF CONC.
WALL <Sc JT.
SEAL
024995
United Water - Triangle WWTP, Durham Co.
j DATE: 2/22/08
SK-S3
SHEET 3 OF 3
E3
APPLY SIKADUR 31 HI-MOD GEL EPOXY-/ V_
ADHESIVE (Sc SIKADUR COMBIFLEX
PERFORATED HYPALON SEALING STRIPS
NOTE:
WALL IF/ REPAIR
SIM. FOR BASE
SLAB l/F REPAIR.
EXIST. EJ MAT’L-\
EXIST. PVC WATERSTOP^ \
EXIST. 1”0 (*) SMOOTH STL“\ \ \
DOWEL/SLEEVE ASSEMBLY \ \ \
4 A
■ &
/-EXIST. EXP. JT.
/ MAT’L
1 - PLAN - WALL l/F & 0/F EXP. JOINT REPAIR SYSTEM
SCALE: 1/2"=1’-0”
FILL JOINT CAVITY w/ De NEEF'S
OAKUM SOAKED IN SIKA FIX HH
POLYEURETHANE LIQUID CHEMICAL
GROUT (REF. NOTE 2)
2 - DETAIL - ENLARGED l/F OF JOINT
SCALE: 3" = r-0"
A
CREED
1730 Vorsity Drive, #500, Venture IV Bldg.
Roleigh, North Corolino 27606
Phone:[phone] Fox:[phone]
www.mckimcreed.com
GRIND EXIST. WALL CORNERS ?
TO 1/4” CHAMFER OR
FILLET
4
Z1
T
<7
• • i• '
NOTES:
1. SEALANT TO BE SIKAFLEX -2c NS/SL OR AN APPROVED EQUAL. INSTALL BACKER ROD AS REQ’D.
2. OAKUM TO BE INSTALLED TIGHT INTO JOINT FOR FULL WIDTH & DEPTH TO EXP. JT. MAT’L.
EXPOSED CONC. JOINTS TO BE CLEAN OF ALL LOOSE DIRT <3c DEBRIS. INSTALL
OAKUM AS FOLLOWS:
a. ) CUT OAKUM IN TO 2 TO 3 FT. LENGTHS <Sc HAND LOOSEN FIBRES.
b. ) SUBMERGE OAKUM IN THE SIKA FIX HH. WIPE EXCESS MAT’L WHEN REMOVING FROM
CONTAINER USED TO SOAK THE OAKUM.
c. ) WET JT. w/ WATER TO PRIME JT. SURFACE.
d. ) DIP STAURATED OAKUM INTO WATER TO START CATALYZATION & PLACE SATURATED OAKUM
IN THE JT. & SPRAY THE VISIBLE SURFACE w/ WATER.
3. APPLY SIKADUR 31 & COMBIFLEX HYPALON STRIPS AS RECOMMENDED BY THE MFG.
4. REFERENCE CONSTRUCTION SKETCHES SK-S1 & SK-S2 FOR ADDITIONAL NOTES & INFORMATION.
BNR BASIN - EXPANSION JOINT BASE SLAB
& WALL REPAIR
I L_ f
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Ti ■ v -i
S8
May 6, 2008
Re:
Dear Mr. Vinzani:
If you have any concerns, please give me a call at [phone].
Enclosure:Water Pollution Control System Designation Form
cc:
JRP/js
Please find attached the Water Pollution Control System Designation Form for the Triangle
Wastewater Treatment Plant. Effective May 6, 2008, Marvin Carter is no longer the Back Up
ORC. Shawn Davis, certificate #988558, will serve in the capacity of Back-Up ORC. Ralph
Glenn Vance is the ORC of record. Please use the designation as listed above and detailed in
the attached form to supersede any information held by DWQ on this matter. Please change
your records accordingly.
RETURN RECEIPT REQUESTED
CERTIFIED MAIL # 7005 2570 0001 4784 4965
Marvin Carter, United Water
Shawn Davis, Back Up ORC, United Water
Pete Corsaro, Project Manager, United Water
Glen Vance. ORC, Operations Manager, United Water
Mack Wiggins, Environmental Specialist, DWQ
Jerry Rimmer, Supervisor TACU Unit, DWQ
Mr. Gil Vinzani
NPDES East Unit Supervisor, DWQ
1617 Mail Service Center
Raleigh. NC 27699-1617
120 E. Parrish Street, Law Bldg., 1st Floor, Durham, N.C. 27701 [phone] Fax [phone]
Equal Employment/Affirmative Action Employer
Change in Operator in Responsible Charge (ORC) for Triangle WWTP,
NC0026051
COUNTY OF DURHAM
ENGINEERING DEPARTMENT
Sincerely,
//Joseph R. Pearce, P.E.
y POTW Director
Yo\ JiL
wr .pi MSf 122® ( -
I
General Information:
Permittee Owner/Officer Name:Durham County / Glen Whisler
Mailing Address: 120 East Parrish Street Law Building 1st Floor
City:Durham State:NC Zip: 27701
Telephone Number [phone] Fax Number ( 919 J 560-0740
Signature: Date:
Facility Information:
Facility Name: Triangle WWTP
Pennit Number: NC 0026051 County: Durham
I SUBMIT A SEPARATE FORM FOR EACH TYPE OF SYSTEM I
Mark (X) Type of Facility Grade Mark (X) Type of Facility
X 4
Operator in Responsible Charge:
Print Name: Ralph Glenn Vance
Certificate Type and Grade: Waste water Grade IV
Work Telephone: [phone] Signature:
Back-Up Operator in Responsible Charge:
Print Name: Shawn Davis
Certificate Type and Grade:Waste water
Work Telephone: ( 919)201-6274
Mail or Fax to:
Fax: [phone]
Wastewater Plant
Physical/Chemical
Collection System
Spray Irrigation
Land Application
Water Pollution Control System Designation Form
WPCSOCC
NCAC 15A:08G .0201
WPCSOCC
1618 Mail Service Center
Raleigh, N.C. 27699-1618
Certificate #: x990409
Grade III Certificate#: 988558
Signature: x?
General Information:
Mailing Address:
Date:
Facility Information:
G.Facility:
! SUBMIT A SEPARATE FORM FOR EACH TYPE OF SYSTEM !
Mark (X) Type of Facility Class (1 -4)Class
Operator in Responsible Charge:
Social Security # :
Work Telephone: ( ?/?) c^O/- ^.^7Zsignature:
Back-Up Operator in Responsible Charge:
Social Security # : C HZ-S"/Print Name:
Work Telephone: ( Signature:
Mail or Fax to:
Revised 10/2000
Certificate #: ? 0 7 O
Spray Irrigation
Land Application
Subsurface
£/z/?r
N/A
N/A
N/A
Wastewater Plant
Physical/Chemical
Collection System
Water Pollution Control System ORC Designation Form
WPCSOCC
NCAC 15A:08G .0201
Permittee Owner/Officer Name:
I fi^tsk
WPCSOCC
1618 Mail Service Center
Raleigh, N.C. 27699-1618
Fax: [phone]
>—
Certificate Type and Grade: C2 /
Telephone Number: ( ?l? )
Signaturet^^Tj/5
-----------------------------------------------------
State: AJ C. Zip: 6 {-
County: Q Vi ex
Print Name: £.<x«,IU. G
Certificate Type and Grade: G S 3> Certificate #; 9 W 7^
1 Cl C-nr
Q
Permit Number: CO Q GS 6)00S
r
General Information:
c e
Mailing Address: ixb
State: CL Zip: City:
Facility Information:
Facility:Ofc I ‘**1^
Permit Number: Q>C-S
! SUBMIT A SEPARATE FORM FOR EACH TYPE OF SYSTEM ’
Mark (X) Type of Facility Class (1 -4)Class
Operator in Responsible Charge:
Print Name: Social Security //:
Certificate Type and Grade: Certificate #:
Work Telephone: () __Signature:
Social Securitv U :
Certificate Type and Grade:
Work Telephone: ( Signature:^
Mail or Fax to:
Revised 10/2000
County:
Certificate #:
Wastewater Plant
Physical/Chemical __
Collection System
Spray Irrigation
Land Application
Subsurface
N/A
N/A
N/A
Water Pollution Control System ORC Designation Form
wpcsocc
NCAC 15A:08G .0201
WPCSOCC
1618 Mail Service Center
Raleigh, N.C. 27699-1618
Fax: [phone]
Date:
Back-Up Operator in Responsible Charge:
Print Name: I Utj/r
Telephone Number: (
Signature: /t
Permittee Owncr/Officer Name: ,
r
i
General Information:
vA,
Date:
Facility:
Permit Number:
! SUBMIT A SEPARATE FORM FOR EACH TYPE OF SYSTEM I
Mark (X) Type of Facility Class (1-4)Class
Operator in Responsible Charge:
Print Name: Social Security it :
Certificate Type and Grade: Certificate #:
Work Telephone: () Signature:
Certificate Type and Grade: Certificate #:
Work Telephone: (5/? ) Signature;
Mail or Fax to:
Revised 10/2000
Wastewater Plant
Physical/Chemical
Collection System
Spray Irrigation
Land Application
Subsurface
N/A
N/A
N/A
Water Pollution Control System ORC Designation Form
WPCSOCC
NCAC 15A:08G .0201
WPCSOCC
1618 Mail Service Center
Raleigh, N.C. 27699-1618
Fax: [phone]
1------
County:
Mailing Address:
City:
Telephone Number: (5 )
Facility Information:
AW
Social Security # :
Permittee Owner/Officer Name: e> S-e pV\
I 6 fix, _________
State: A3 C. Zip: O |
■t
\r\, ci
Back-Up Operator in Responsible Charge:
Print Name: < S
General Information:
Signature: Date:
Facility Information:
Facility:
Permit Number:(yj C,^S 0003
! SUBMIT A SEPARATE FORM FOR EACH TYPE OF SYSTEM !
Mark (X) Type of Facility Class (I -4)Class
Operator in Responsible Charge:
Print Name: Social Security ti :
Certificate Type and Grade: Certificate #:
Work Telephone: ( Signature: )
Social Security # :
Certificate #:
Mail or Fax to:
Revised 10/2000
Wastewater Plant
Physical/Chemical
Collection System
Spray Irrigation
Land Application
Subsurface
N/A
N/A
N/A
Water Pollution Control System ORC Designation Form
WPCSOCC
NCAC 15A:08G .0201
WPCSOCC
1618 Mail Service Center
Raleigh, N.C. 27699-1618
Fax: [phone]
Work Telephone: (*) (^7) & Signature:
L
Telephone Number:
Mailing Address: _
City:
Back-Up Operator in Responsible Charge:
Print Name:
Certificate Type and Grade:
County:
Permittee Owner/Officer Name: 3o .s-epn <
I2& ^4
Stated C Zip: ^T7^l -
June 3, 2008
Re:
Dear Mr. Vinzani:
If you have any concerns, please give me a call at 919-560-0735.
Ends.: (4) Water Pollution Control System Designation Forms
cc:
JRP/jld
Change in Operator in Responsible Charge (ORC) for Durham County Wastewater
Collection System, Triangle Wastewater Treatment Plant (TWWTP), WQCS00038
Mack Wiggins, Environmental Specialist, DWQ
Jerry Rimmer, Supervisor TACU Unit, DWQ
Pete Corsaro, Interim Project Manager, United Water
Glenn Vance, TWWTP ORC, United Water
Ronald Ketteman, Collection System ORC, United Water
Dana Zoy, United Water
Robert Hilliard, United Water
Marvin Carter, United Water
Shawn Davis, United Water
120 E. Parrish Street. Law Bldg., 1st Floor, Durham. N.C. 27701 [phone] Fax [phone]
Equal Employment/Affirmative Action Employer
Gil Vinzani
NPDES East Unit Supervisor, DWQ
1617 Mail Service Center
Raleigh, NC 27699-1617
COUNTY OF DURHAM
ENGINEERING DEPARTMENT
Sincerely,
/ Joseph R. Pearce, P.E.
Utility Division Manager/POTW Director
Please find attached the Water Pollution Control System Designation Form for the Durham County
Wastewater Collection System. Effective May 30th, 2008, Ronald Ketteman - certification # 990673
is the Operator in Responsible Charge (ORC). In addition, Dana Zoy - certification # 990590, Shawn
Davis - certificate # 986694, Robert Hilliard - certification #986772, and Marvin Carter - certification
#988139 are the back-up Operators in Responsible Charge (ORC). Please use the designations as
listed above and detailed in the attached forms to supersede any information held by DWQ on this
matter. Please change your records accordingly.
....
JUN I 8 2008
June 11, 2008
Re:
Dear Ms. Gore:
Examples of flow allocation extension worksheets completed by the standard method and by the proposed
alternative method are attached. Using the alternative method, it is believed that Triangle Wastewater
Treatment Plant will not exceed its NPDES permitted flow capacity and will be able to serve the Town of
Cary during its temporary term of need.
120 E. Parrish Street, Law Bldg., 1st Floor, Durham, N.C. 27701 [phone] Fax [phone]
Equal Employment/Affirmative Action Employer
Durham County
NC0026051
WQCS00038
Durham County Triangle WWTP
COUNTY OF DURHAM
ENGINEERING DEPARTMENT
The alternative method proposed for flow allocation is to use the sum of the maximum monthly flows (for
the previous calendar year) for each industry, instead of the permitted flow values. Attached please find a
table of the monthly average flows of each industry, with a column showing the maximum month
discharge from each industry. Due to expected increases in the Town of Cary flow, the Town of Cary
flow would be allocated at the interlocal agreement flow. In 2007, the total non-Cary SIU permitted flow
was 2.484 MGD. The maximum non-Cary SIU discharge flow was 1.01 MGD in August 2007. The sum
of the monthly maximum flows for each industry during this same period is 1.45 MGD. This is a 44%
safety factor and is sufficient to ensure the TWWTP does not exceed its NPDES permitted flow capacity.
Ms. Deborah Gore
NCDENR-DWQ -PERCS
1617 Mail Service Center
Raleigh, North Carolina 27699-1617
Collection System Flow Allocation Method Revision
Program:
NPDES #:
Collection #:
WWTP:
As discussed during our May 27, 2008 meeting, Durham County is proposing an alternative method for
determining appropriate collection system flow allocation for our specific facility. The Durham County
Triangle Wastewater Treatment Plant serves the Research Triangle Park, and surrounding areas in
southeast Durham County. Additionally, an interlocal agreement until December 31, 2010 provides for
this facility to temporarily treat up to 5 million gallons per day of wastewater from the Town of Cary.
The Town of Cary has requested that this agreement be modified to at least 2013 and for a flow expansion
up to 6 million gallons per day. Due to a relatively high percentage of contributory flow from Significant
Industrial Users (SIUs) and large differences between permitted and actual flow, the current method of
sewer extension flow allocation is overly conservative for our specific facility.
2.
Additional measures which could be taken should excessive flows become an issue include:
3.
4.
Enclosures:
cc:
JRP/ds
2
As time is of the essence to resolve the Cary flow and load issues your prompt response to this inquiry
would be greatly appreciated. If you have any questions, please call me at [phone].
Glen Whisler, P.E., County Engineer
Andy Lambeth, Project Manager
Barry Herzberg - NCDENR Raleigh Regional Office
More intensive I&I work, such as smoke testing to remove illicit stormwater connections and
monitoring of flowrates from all satellite systems to determine their I&I problems. Problems
discovered could be ordered to be repaired.
Inflow and infiltration (I&I) control continues to be a priority. Almost all manholes with any
potential for submergence in Durham County’s collection system have manhole inflow shields.
SIU Permits and Interlocal Agreements could be re-opened and issued forcing users to discharge
less water to the Durham County collection system.
Industrial Monthly Average Flow Data 2007
Standard Flow Allocation Method Example
Alternative Flow Allocation Method Example
Sincerely,
Joseph R. Pearce
Utility Division Manager/POTW Director
1. A Reuse Water System to Durham and Western Wake County users has received grant funding
and is in the final stages of design. Upon completion approximately 350,000 gallons per day of
reuse water will be used by Durham County, Wake County and Town of Cary customers.
In conclusion, please consider the option for Durham County' to use the proposed alternative method for
allocating flow for sewer extensions. Durham County would like to have the option of offering the Town
of Cary a 6 MGD flow and fifty percent of the maximum allowable headworks load. Durham County
does not believe this will result in NPDES permit flow exceedances if the alternative method is used for
our specific facility.
During the meeting, it was recommended that Durham County propose measures which could be taken to
reduce its discharge flow should the NPDES discharge limit be exceeded. Measures which are currently
in progress include:
Industrial Monthly Average Flow Data 2007
INDUSTRIAL AVERAGE FLOW DATA 2007
INDUSTRY NAMES
N A N A Va
Total T56 T55 1.82 1 59
1.449567|Total w/o Cary 2 484000 0.692802 0.700136 0.667581 0.775203 0.929381 0.723895 0.823763 1.014163 0.789595 0.684739 0.577851 0.420361
Durham County
Triangle WWTF
Printed 6/13/2008, 2:17 PM
Page 1 of 1
0 2500
0.0100
0.0750
0 1850
00550
0,0720
0 0390
/ 48
0.8628
0 0699
01736
0.0093
0.0150
0.0228
0 2280
0 1140
0,0280
0 0290
0,0320
00357
0.0011
00538
0.0985
0.0065
0 0097
■lul
MGD
AiiH
MGDMGD
0,0030
5 0000
0.1200
0.3220
03550
0,0980
0 2500
0 6500
250,000
10,000
75,000
185,000
55,000
72,000
iQ.dod
Feb
MGD
0.002100
0,8596
0,0769
0,1835
0.0079
00100
0,0311
0 1650
0.0750
0.0320
0.0280
0.0140
00750
0.0015
0.0565
00594
0.0224
0,0088
Mai
MGD
0 8836
0 0614
0,1640
0.0117
00080
0.0289
01800
0.0880
0.0260
0.0310
0.0160
0 0686
0 0011
00617
0,0663
0.0057
0.0101
Apr
MGD
0,8516
0,0735
0 1532
0,0126
00100
0.0393
01640
0.0810
0 0260
00390
0.0160
0 0514
00010
0,0598
0.0757
0 0054
0.1072
0 0121
1.63
.Inn
MGD
08715
0.0708
0 1365
0 0095
00180
0 0272
0,3000
0 1480
0 0370
0.0610
0 0250
00353
0.0006
00705
0.1126
00068
0.0117
0 0243
1.70'
0,7113
0,0787
0,1455
00122
0.0240
0,0334
0 4040
0,2030
0,0800
0,0600
00310
00376
0 0011
00803
0 1470
00068
00196
0,6239
1.?3
0,6764
0 0729
01283
00143
0.0190
0.0266
02890
0.1380
0,0770
0 0170
0.0300
0.0328
0,0022
0.0578
0.0947
0,0046
00143
6.0336
1 47
1,0983
0 0723
0,1172
0,0119
0.0160
0.0274
0,1520
0.0730
0,1120
00190
0 0300
0.0281
0.0034
0.0571
0.0474
0.0106
0.0097
6.0248
1.68
Dec
MGD
0 076453
0.003708
0 080297
0146967
0 022380
0.107190
0.632986
^732878
Monthly Ave. Permit Limits
Ral/day
3,000
5,000,000
120,000
322,000
355,000
98,000
250,000
650,000
May
__________ ___________ MGD __________ ______________________
No Discharge No Discharge No Discharge No Discharge No Discharge No Discharge
0,8916
0.0676
01746
0.2410
0 0310
0.0274
0 1840
0,0940
00270
0 0240
0,0160
0.0365
0.0012
00631
0.0876
00035
0.0119
Sep
MGD
l\ov
MGD
Oct
__________ MGD ______________________
No Discharge No Discharge No Discharge No Discharge
0,8810
0,0709
0,0949
0.0115
0.0130
0 0349
0 2530
00980
0 0710
0,0270
0.0340
0.0358
0.0037
0.0512
0.0885
0.0052
0,0109
6^0112
i~57
1.2833
Flow Meter o1
0.1014
0.0129
0.0150
00258
01200
0.0430
00320
0.0150
0.0110
0.0251
0.0002
0.0431
0.0415
0.0090
00084
0.0180
1.70
Maa Month
MGD
0.002100
1 283311
0 078687
0 183464
0.241000
0.031000
0.039335
0.404000
Astro Pak Coipoialions_______
Town of Cary______________
Cintas
Cree-Pipe 001_____________
Cree RTP_________________
Dupont (E.I. Denemours)
Eisai_____________________
Glaxo - Total
Glaxo Pipe 001_____________
Glaxo Pipe 002
Glaxo Pipe 003_____________
Glaxo Pipe 004_____________
IBM
JMC (USA) Inc____________
NC IDEA (formerly MCNC)
RT1 - (Research Triangle Inslitut
SCM Metals______________
Sumitomo
DC-006
DC-023
DC-015
DC-012
DC-005
DC-019
DC-009
Permit
number
DC-039
DC-038
DC-037
DC-030
DC-040
DC-018
DC-029
DC-010
■Jan
MGD
No Discharge
0 7617
0,0784
0,1683
0.0079
0,0120
0.0378
01520
0,0680
0,0180
0 0300
0 0180
0,0765
0,0008
0,0587
00592
0.0163
00089
0 0160
1 45
Average Effluent Flow minus Cary &7:7SIU
Current Total Flow Permitted + Uncontrollable MGD10.67565
WWTP Permitted Capacity 12 MGD
Proposed Addition Project Number
Total Proposed Addition 0.01028
Total Actual and Obligated 10.67565
Percent Permitted Flow Used 89%
0.00000
0.000001 MGD
0.01028 MGD
TTA Outfall A
HoteHndigo
108 Alexander
Shiloh Crossing
RTI Building 08
]mperial Tower
SIU Permitted Flow _
Cary ILA Flow
Average Effluent Flow last 12 months
Cary & SIU Flow last 12 months
Uncontrollable Flow
Permitted Under Construction
2.484 MGD
5
4.5
1.74641 MGD
2.7536 MGD
0.43805 MGD
0.00000 MGD
MGD
MGD
MGD
MGD
MGD
MGD
MGD
MGD
MGD
MGD
MGD
MGD
Notes
Does not include Cary's SlUPermit
Future flows will be permitted jndividually
Central Park Pump Statjon
Re-routing existing line no flow addition
Future Flowwill be permitted individually
gravity line to TWWTP __
Pending - Page Road Pump Station
Available Flow Capacity
_______________________Triangle Wastewater Treatment Plant
Standard Flow Allocation Method Example
MGD
MGD
Average Effluent Flow minus Cary &7/7SIU
Current Total Flow Permitted + Uncontrollable 10.63165 MGD
WWTP Permitted Capacity 12 MGD
Proposed Addition ProjectN umber
0.01028
Total Proposed Addition 0.01028
Total Actual and Obligated 10.63165
Percent Permitted Flow Used 89%
SIU Max Monthly Flow during 2007
Cary ILA Flow________
Average Effluent Flow last 12 months
Cary & SIU Flow last 12 months
Uncontrollable Flow
Permitted Under Construction
1.44 MGD
6
____4.5 MGD
17464
275361 MGD
0.43805 MGD
0.00000 MGD
______MGD
0.000001 MGD
0.000001 MGD
MGD
MGD
MGD
MGD
MGD
MGD
MGD
MGD
MGD
Notes
Does not include Cary's SIU Permit
TTA Outfall A
Hotel Indigo_
108JUexander^
Shiloh Crossing
RTI Building 08
Imperia [Tower
Future flows will be permitted individually
Central Park Pump Station
Re-routing existing [ine nojow addition
Future Flow will be permittedjndh/idually
gravityjine to TWWTP ____
Pending^- Page Roa^Pump Station
Available Flow Capacity
________________________Triangle Wastewater Treatment Plant
Alternative Flow Allocation Method Example 3
r
June 17, 2008
RE:
Dear Mr. Vinzani:
Mr. Gil Vinzani, P.E.
Supervisor, Eastern NPDES Program
NCDENR - DWQ
1617 Mail Service Center
Raleigh, NC 27699-1617
120 E. Parrish Street, Law Bldg., 1st Floor, Durham, N.C. 27701 [phone] Fax (.919) 560-0740
Equal Employment/Affirmative Action Employer
Triangle Wastewater Treatment Plant
Durham County, North Carolina
NPDES Permit No. NC0026051
COUNTY OF DURHAM
ENGINEERING DEPARTMENT
Please consider this request for a MINOR modification of the above-referenced NPDES permit
for the Triangle Wastewater Treatment Plant in Durham County. In accordance with your
telephone conversations with Dave Heiser of McKim & Creed earlier this year, enclosed
herewith is a site plan for the proposed Phase III Biosolids Facility, a revised completion
schedule, and a Biosolids Management Plan Update - Basis of Design for review. No increases
in flow or pollutant loads, changes to permit effluent limits, or modifications to the permitted
facility treatment processes are included in this request - simply a modification to the method of
biosolids management as listed in the NPDES Permit.
The Phase III Biosolids Facility will provide for liquid waste activated sludge storage, a
dewatering facility and truck loading for a contract composting operation. The attached Basis of
Design documents the design elements for Phase III. Based on the current project schedule,
Phase III would be placed on-line at the end of 2010.
2 Oaos■A w
cc:
JP/ds
S:\Utility Division\Utilities.. Front Desk 2008\6-16-08 Vinzani Letter doc
Mr. Gil Vinzani, P.E.
June 17, 2008
Page 2
We trust you will find this information acceptable, and will be able to modify the current NPDES
Permit accordingly. If you have any questions, or require any additional information, please
contact either me or Dave Heiser, PE, at McKim & Creed (919-233-8091).
Mack Wiggins, NCDENR Raleigh Regional Office
Dave Heiser, PE, McKim & Creed, PA
Bryan Blake, PE, McKim & Creed, PA
Sincerely,
A O
Joseph Pearce, P.E.
Utility Division Manager
Durham County Engineering Department
Encl: Site Plan for the Proposed Phase III
Biosolids Facility - Basis of Design
Revised Completion Schedule
Biosolids Management Plan Update
NOTTS:
1. OEVATTONS APE BASED ON NAVD M DATUM.
WS GPS SUR'MTY NOTTnw.4/.
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Wii/V-.' i-'t.V h'S
Al'MJim SA'M
URIVCpAvr.o Acer
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EQ. BASIN OW
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_____ ___ _____-»SS^TO~—.n — J
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1
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MsnNa •j.uocc Mct.m
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DEWATERING FACILITY ■u
PROPOSED SITE PLANIntamal SHi ht(p://wwwmckimc—Ocom
DURHAM COUNTY
NORTH CAROLINA
TRIANGLE WASTEWATER TREATMENT PLANT
PHASE III
-ORIZON r<
»•- Jtf
xanc*.
,-.T‘ /.VI r/T.w' Me r.'rw
TRUCK
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VorsUy Drive. SuHe SCO
s: (919)233-809'. Fox: (919)233-803'
I. Norin Coroilna 27606
1730 V
Phone: <
Raleigh.
4§5>M2KIM6'CREED
Jdj
I]
E
aUOGE HOLDING­
TANKS (SHTa)
n.OOOWAY INFORM A OQN TAKEN
FROM 2006 FEM A MAP PANEL
|0737 SUFFIX J
J '
THE GRID COORDINATES SHOWN ON THIS MAP WTRE DERIVED BY
VNS (\4RTUAL REFERENCE STATIC*) GPS USING A DUAL FREQUENCY
RECEIVER. THIS ME TH CO RESULTS IN NAD 83 (CWS 96) POSTIONS
AND NAVD M (MSI) ELEVATIONS USING TX CONTNUOUSLY
OPERATING STATIONS MAJNTAKED BY NORTH CAROLNA GFOOERC
SURVEY.
• Submit NPDES Permit Modification Request June 15, 2008
• Receive Approved NPDES Permit Modification August 30, 2008
Submit to State for A-T-C September 15, 2008
Receive A-T-C from State March 15, 2009
• Advertise Project.March 23, 2009
Receive Bids April 30, 2009
Award Construction Contracts.May 31, 2009
Execute Construction Contracts July 31, 2009
Notice to Proceed for Construction.August 7, 2009
• Construction Completion November 7, 2010
REVISED PROJECT SCHEDULE
June 2008
DURHAM COUNTY
TRIANGLE WASTEWATER TREATMENT PLANT
BIOSOLIDS PROCESS TRAIN IMPROVEMENTS
DURHAM COUNTY TRIANGLE WASTEWATER TREATMENT PLANT
BIOSOLIDS MANAGEMENT PLAN UPDATE
PHASE III - BIOSOLIDS FACILITY BASIS OF DESIGN
DURHAM COUNTY, NORTH CAROLINA
June 13,2008
Municipal Contact:Prepared By:
MCKIM&CREED
Mr. Joseph Pearce, PE
Durham County
120 East Parrish St.
Durham, NC 27701
[phone]
Mr. David M. Heiser, PE
McKim & Creed, P.A.
1730 Varsity Drive
Raleigh, NC 27606
[phone]
xi L
ra f
c> C
Jc/rZ 13484
Introduction
Design Influent Wastewater Characteristics and Design Biosolids Production Quantities
are as
1
The design influent wastewater characteristics and design biosolids production quantities
contained in McKim & Creed's Phase III Biosolids Management Systems Engineering
Alternative Analysis Amendment No. 2 dated July 10, 2007 and as summarized below in Tables
1 and 2. The biosolids production quantities shown in Table 2 are calculated using both the
biological solids yield factor of 0.70 pounds per pound of BODs loading in the plant influent
calculated from the current WAS production at the plant, and the design solids yield factor of
0.95 pounds per pound of BODs loading.
Durham County has decided to proceed with contract composting as an interim step for
Phase III in their biosolids management program. This interim step shall provide for liquid
storage of waste activated sludge (WAS), on-site dewatering, and a truck loading facility for
dewatered sludge which will allow for contract hauling to a permitted composting facility. The
decision to proceed with contract composting was not to preclude the County from ultimately
providing for heat drying or other stabilization option in the future.
TRIANGLE WASTEWATER TREATMENT PLANT
DURHAM COUNTY
BIOSOLIDS MANAGEMENT PLAN UPDATE
CONTRACT COMPOSTING ALTERNATIVE
PHASE III - BIOSOLIDS FACILITY
BASIS OF DESIGN
JUNE 13, 2008
TABLE 1
12
36
NH3-N
2
DESIGN CONDITIONINFLUENT PAR AM ETER
DURHAM COUNTY TRIANGLE WWTP
DESIGN INFLUENT WASTEWATER CHARACTERISTICS
200
20,020
180
18,020
40
4,010
4
400
25
2,500
Organic Loading (BOD5)
(mg/1)
___________(Ibs/d)
Total Suspended Solids
(mg/1)
______ (lbs/d)
Total Nitrogen
(mg/1)
(lbs/d)
(mg/1)
I ___ (lbs/d)
Total Phosphorus
(mg/1)
(____________(lbs/d)
Average Daily Flow (MGD)
Peak Hourly Flow (MGD)
TABLE 2
DESIGN BIOSOLIDS PRODUCTION QUANTITIES
12.0 MGD 12.0 MGDAVERAGE DAILY INFLUENT FLOW
ORGANIC LOADING (BODs)20,020 Ibs/d 20,020 Ibs/d
12, 330 wet tons/yr 16, 480 wet tons/yr
15,415 cy/yr 20,600 cy/yr
3
DESIGN YEAR CONDITIONS
EQUIVALENT DEWATERED BIOSOLIDS CAKE
PRODUCTION FROM CENTRIFUGE DEWATERING
Weight @ 22% TS
WASTE ACTIVATED SLUDGE (WAS) PRODUCTION
@0.5%TS (@ 12 MGD)
@0.75%TS (@ 12 MGD)
0.70 Ibs/lb BODs
8.5 Ibs/lb TP
476,400 gals/d
317,600 gals/d
0.95 lbs/ lb BODs
8.5 Ibs/lb TP
BIOSOLIDS PRODUCTION
Biological Solids
Chemical Solids (phosphorus) (‘X3)
Total Biosolids Production
356,500 gals/d
237,600 gals/d
2,560 dry tons/yr
155 dry tons/yr
2,715 dry tons/yr
3,470 dry tons/yr
155 dry tons/yr
3,625 dry tons/yr
BIOSOLIDS YIELD
Biological Solids (2)
Chemical Solids (phosphorus) <*)
DESCRIPTION
Volume @ 22% TS
(1) Based on an average influent phosphorus concentration of 4 mg/1.
(2) Includes biosolids yield from carbonaceous oxidation, as well as biological yield associated with biological nutrient removal
(both nitrogen and phosphorus).
(3) Assumes phosphorus concentration can be effectively reduced to 1.0 mg/1 biologically. The biosolids generated as a result of
biological phosphorus removal are accounted for in the Biological Solids category. The chemical solids listed assume sodium
aluminate will be utilized to reduce residual TP concentration from 1.0 mg/1 to <0.28 mg/1
WITH CURRENT < WITH DESIGN SOLIDS
|SOLIDS YIELD FACTOR \
Operation Overview
area
4
The new structures, liquid WAS storage. Dewatering Building and truck loading station, shall
be located within the "footprint" of the existing southern aeration basin. The new structures
shall be arranged to facilitate the future addition of a dryer building and additional liquid WAS
storage, minimizing impact on the contract composting operations.
The unthickened WAS (approximately 0.75% TS) will be pumped via variable speed
progressive cavity dry-pit pumps (centrifuge sludge feed pumps) to the dewatering building
housing the high solids centrifuges. The centrifuge sludge feed pumps are anticipated to be
housed below grade to allow for a flooded pump suction and to allow complete emptying of the
liquid storage tanks.
The contracting composting operation will allow the County to manage biosolids in a more
routine, consistent, and efficient manner than the current process of utilizing the existing sludge
lagoon, as well as allow for a future expansion to a heat drying process.
The existing southern clarifier shall be modified to accept backwash water from the existing
filters and centrate from the dewatering facilities for flow equalization and pumping back to the
BNR process influent distribution box.
It is anticipated that the high solids centrifuges will produce a 22% solids sludge. The
dewatered sludge will be conveyed to the truck loading station. The truck loading station shall
provide space for dual truck loading and shall be located adjacent to the Dewatering Building.
The Dewatering Building will be a one-story facility with a basement area located near the
liquid WAS storage tanks and will house the following components:
> Centrifuge area
> Polymer feed and storage
> Office/control room
> Test sample/preparation room
> Electrical room
> Single restroom/shower
> Sludge feed pump area
Waste activated sludge (WAS) will be wasted from the existing RAS/WAS pumping station to a
WAS liquid storage tank. The tank is proposed as a 1.0 MG two cell (0.5 MG each cell) common
wall cast-in-place concrete storage tank. The tank will be provided with an aeration and mixing
system in each cell.
Design Criteria
Waste Activated Sludge Pumping and Storage
5
The liquid WAS storage tank will be a cast-in-place concrete structure with common wall
construction for the two cells. The western end of the structure, walls, and footing will be
provided with water stops and dowel inserts to accommodate the future 1.0 MG storage
expansion if needed. The tanks will have open tops and no odor control system will be
provided. See Table 3 for a summary of the design criteria for the sludge holding tanks.
The aeration and mixing system for the sludge holding tanks will be sized for aeration and
mixing as a "nursing" tank for the centrifuges, and not to provide for aerobic digestion.
Each of the two tanks will be equipped with independent submersible aerators and mixers that
will be used to keep the tank contents fully mixed, as well as to provide for aeration to keep the
dissolved oxygen at an acceptable level. Two mixers and two submersible aerators will be
installed in each tank.
Using the current solids yield factor for biological solids, the 1.0 MG total storage volume
provides 4.2 days storage of liquid storage capacity at WAS design year (12 MGD) production
(237,600 gpd @ 0.75% TS) or 8.4 days storage at 6.0 MGD. Using the design solids yield factor, 3
days storage of liquid sludge at 12 MGD plant flow will be provided, or 6 days storage at 6
MGD.
Floating decanters with submerged weirs will be used (one per tank) to withdraw supernatant
from the tanks at the maximum water level down to approximately ten feet of water depth.
This will provide an operating range of approximately twelve feet. Supernatant from these
decanters will be routed to the equalization basin.
Each tank will be provided with level indication so the operators will know the liquid levels in
each tank to assist them with selecting which tank to utilize for wasting. Separate float switches
will be installed in each tank to cut off the mixers and aerators in that tank should its water level
fall to a specified elevation below which the mixers and aerators will not be effective.
WAS is pumped from the existing RAS/WAS Pump Station that serves four flocculating, high-
rate center-feed clarifiers and currently discharged to the existing sludge lagoon. The discharge
of the WAS pumping station will be diverted to the new liquid WAS storage tanks via an
extension of the existing force main. WAS at approximately 0.5% TS concentration (initial year)
and 0.75% TS concentration (starting in 2012) will be pumped (via the existing submersible
WAS pumps located adjacent to the new clarifiers) to one of two new 500,000 gallon sludge
holding tanks (1.0 million gallons total storage capacity). WAS flow will be metered via the
existing in-line magnetic flow meter located at the WAS pump station. The WAS flow is
continuously monitored and totalized via the Plant SCADA system. Scum from the final
clarifiers will also be pumped to these storage tanks.
TABLE 3
WASTE ACTIVATED SLUDGE HOLDING TANKS
6
WASTE ACTIVATED SLUDGE LIQUID STORAGE SYSTEM
DESIGN CRITERIA
Floating Style Dissolved Oxygen Sensors
0.1 mg/1 to 2.0 mg/1
Pressure Transducer
1 unit/cell
Submersible Mixers
Two Per Tank
1 Float Switch/Cell
Floating; submerged weir
1 unit/cell
500 gpm (minimum 4 hour cycle)
Motorized plug valve
12' (10 to 22 foot SWD)
Positive flow indicator (1/cell)
Submersible Aerators
Two Per Tank
75 lbs O2/hr (Total)
1 Float Switch/Cell
Timers and/or Dissolved Oxygen Levels
Total Volume__________________________________
# of Independent Cells
Volume per Cell (MG)___________________________
Dimensions (each cell)
Width
Length
Wall Height
_____Max Liquid Depth___________________________
Materials of Construction
Provide for expansion by addition of two future cells
Mixing System
Type
Number of Mixers
Low Level Cut Off
Aeration System
Type
Number of Aerators
Oxygen Transfer Rate Required
Low Level Cut Off
Aeration Control
Aeration Monitoring
Type
DO Concentration Range
Decanters
Type
Number of Units/Cell
Maximum Decant Rate
Control
Minimum Vertical Travel Required
Flow Detection
Level Indication
Type
Number of Units
1.0 MG
2
0.50
33'
95'
24'
________________2Z
Cast in place concrete
Centrifuge Dewatering
7
As noted previously, for the initial year of operation two feed pumps, two polymer systems and
two centrifuge units will be installed in the new facilities.
The suction header for the feed pumps shall be furnished with two in-line grinders (one per
tank suction line). The grinder units will allow for grinding of material in the waste activated
sludge that may have reformed larger solids in the holding tanks.
The suction and discharge piping for the sludge feed pumps will be arranged to allow for the
addition of a third (future) sludge feed pump.
The centrifuges will be installed inside the proposed new Dewatering Building located adjacent
to the sludge holding tanks. The new building will also house the new mix/feed emulsion
polymer feed systems, electrical equipment, control panels and accessory equipment.
The waste activated sludge will be pre-conditioned with emulsion polymer injected to the feed
sludge via a flange-mounted polymer injection ring to assist in achieving a design dewatered
cake solids concentration between 20% and 22% TS. Sludge cake produced in the dewatering
process will be conveyed to the truck loading station. Centrate will be conveyed to the new
equalization basin via a new gravity sewer, and blended and equalized with other process
wastestreams before being pumped back to the BNR process influent distribution box.
The design hydraulic loading capacity for each centrifuge is 156 GPM at a feed sludge
concentration of 0.75% TS. During the initial year (6 MGD), it is anticipated that the dewatering
system will operate for 62 hours per week (2.6 twenty-four hour days) with two units operating,
but will need to increase to run 124 hours per week (5.2 twenty-four hour days) with two units
operating to accommodate the design year (12 MGD) loadings. The centrifuge sizing was
generally designed to accommodate "design year" loadings in 5.2 twenty-four hour periods
Liquid waste activated sludge will be pumped from each of the two sludge holding tanks to a
new high solids centrifuge dewatering operation. Two progressive cavity dry-pit pumps (one
per centrifuge) will be used to feed the two centrifuges. Each pump will be equipped with a
variable frequency drive to allow the operator to optimize the dewatering operation. The feed
pumps will be installed in the lower level of the Dewatering Building and will be manifolded
such that the pumps can draw suction from either of the two WAS liquid sludge holding tanks
via separately valved inlets. In addition, the discharge from the two pumps will be manifolded
to allow them to feed either of the two centrifuges.
Due to the wash down, flushing and energy requirements for startup and shutdown, it is
recommended that the County plan to operate the dewatering system continuously, 24 hours
per day for the required total number of hours each week (rather than starting and stopping the
system for limited periods during the week).
TABLES
■
10
HIGH SOLIDS CENTRIFUGES AND ACCESSORIES
DESIGN CRITERIA
50
5.2
24
1,170 (Dry Weight)
18,720 @ 0.75% TS
5,494 @ 22% TS
412 @ 22% TS
2 duty
0.75% - 2.0%
20% - 22%
95%
145,000 Ibs/wk, Dry Weight
660,000 Ib/wk, @ 22% TS
132,000 Ib/day, © 22% TS
412 CY/wk, © 22% TS
Progressive Cavity, Positive Displacement
2 (1/Centrifuge)
15 HP
5.5 GPM
200 psi (Max.)
Variable Frequency Drives
Pump Base Load Cells
"Run Dry" and High Pressure
High Solids Centrifuges
Required Centrifuge Capacity (2 units operating)
# Production Weeks/Year
# Production Days/Week
# Production Hrs/Day
Design Throughput (Ibs/Hour)
Design Throughput (gallons/Hour)
Design Cake Production (Ibs/Production Hour)
Design Cake Production (CY/Production Week)
Number of Centrifuge Units
Influent Solids Concentration
Design Cake Solids Concentration
Design Solids Capture Efficiency
Provide layout for one additional future centrifuge
High Solids Centrifuge Accessories
Sludge Cake Pumps
Solids produced/wk
Wet cake produced/production wk
Wet cake produced/production day
Wet cake produced/production week
Pump Type
Number of Units
Horsepower Per Pump
Design Capacity
Discharge Pressure
Pump Control
Centrifuge-to-Pump Speed Control
Pump Discharge Protective Devices
Provide layout for one additional future sludge cake pump
.z : j
Truck Loading Station
Dewatering Building
11
The County will contract with a local company to provide the truck trailers, cabs and
manpower to haul the dewatered cake sludge from this plant to a permitted composting facility.
The truck loading station will have two truck bays and will be approximately 30 ft. wide by 52
ft. long. Three motor-operated swing arm assemblies, each with an in-line knife gate valve, will
be installed near the ceiling, and will be capable of swinging to either truck bay to discharge
sludge cake to the trucks.
The lower wall section shall be brick/block, and depending on the final eave height of the
building, the upper wall section may be metal siding to match the construction of the existing
administration/maintenance building. The roof system shall be standing metal seam with color
to match the existing administration/maintenance building. It is anticipated that the building
area for the dewatering operations will be approximately 4,850 sf (63' x 77').
The Dewatering Building contains two primary areas; one for dewatering operations and one
for housing the centrifuge feed pumps to drain the liquid WAS from the storage tanks. The
dewatering area will be a single story, slab on grade building housing the following
components:
The truck loading station will have a roof system which will match the Dewatering Building.
The lower level shall be open on all four sides. The truck bay areas shall be designed to contain
spillage, and shall be sloped to a trench drain system that will interconnect with the gravity
drain line to the equalization basin. The truck loading station floor shall be concrete in the truck
bay area.
A truck loading station will be provided for the off-loading of the dewatered sludge. The
loading station will be located adjacent to the Dewatering Building and will be furnished
without truck scales. The dewatered sludge will be conveyed from the centrifuge area via
progressive cavity cake pumps that will discharge to two force mains which will transport the
sludge cake to the truck loading station.
• Centrifuge area
• Polymer feed and storage area
• Office/control room
• Test sample/preparation room
• Electrical room
• Single restroom/shower room
In-Plant Flow Equalization and Pumping Facility
12
One (1) submersible mixer and two (2) submersible aerators shall be installed in the converted
equalization basin to provide for mixing to minimize settlement of solids, and for some aeration
to keep the dissolved oxygen at an acceptable level. The basis of design for the aerators is an
oxygen transfer rate (required) of 40 lbs. Oi/hr (total for both aerators).
The existing southern clarifier will be converted to an Equalization (EQ) Basin to flow equalize
sidestream/retum flows from the existing effluent filters, the existing chemical containment
area, decant from the liquid WAS holding tanks, and centrate from the dewatering facilities.
A storage area will be located between the dewatering building and the liquid WAS storage
tanks. This area will provide floor space to accommodate chemical totes and other equipment
storage, as well as a covered area to park the forklift truck when not in use. The floor space for
the storage area, including the stairwell to the basement and the covered area, will be
approximately 1,850 sf (24' x 77').
A large concrete pad shall be provided on two sides of the building for unloading/loading
equipment and supplies, along with a ramp to allow access for a forklift truck into the
dewatering building.
The existing dry pit RAS/WAS pump station located adjacent to the clarifier will be abandoned
and filled with sand. A new submersible pump station wetwell will be installed adjacent to the
EQ Basin on the existing 24" influent pipe to the clarifier. Two new submersible pumps with
variable frequency drive units will be provided to pump equalized flow back to the BNR
process influent distribution box.
A basement area will be provided beneath the storage area floor to house the in-line grinders
and sludge feed pumps. Two pumps will be provided with floor space to accommodate one
additional future feed pump. A monorail/hoist system will be provided to allow for removal of
the basement equipment through an access hatch in the storage area floor above. Floor space
for the equipment area, not including the stairwell, will be approximately 1,335 sf (23' x 58').
The office, sample room, restroom and electrical room will be conditioned space. The
remainder of the dewatering area shall be provided with LP gas heaters and ventilation only.
Vent louvers shall be exhausted to the exterior of the building, but no odor control is to be
provided.
The centrifuge area will be provided with a monorail/hoist system to allow for removal of the
units. The polymer storage area shall be laid out with a recessed floor in lieu of raised curbs for
chemical leakage containment to allow for easier access utilizing a fork lift truck.
9195448590 P.K370:95714718
FAX TRANSMITTAL SHEET
Date: June 23, 2008
TO: Mr. Mack Wiggins FROM:Richard Simms
FAX:FAX:
NOTES/COMMENTS:
□ URGENT □ FOR REVIEW □ PLEASE COMMENT □ PLEASE REPLY
NUMBER OF PAGES INCLUDING COVER: 3
(If you do not receive all pages, please call 919-201-0137)
(919) 571 -4718 FAX: [phone]
SUBJECT: Missing pages 8 & 9 to NPDES Permit No. 0026051 modification
request for Durham County
COUNTY OF DURHAM
ENGINEERING DEPARTMENT
120 E. Parrish Street, Law Bldg, First Floor
Durham, NC 27701
PHONE: [phone] FAX: [phone]
JUN-23-2008 09:14A FR0M:I^^ED WATER
70:95714718 P.8'39195448590
«
each week, 50 weeks per year. This provides time for maintenance and repair each week, and
provides time to do more extensive maintenance during a scheduled two week shutdown each
year.
The dewatered sludge cake will be conveyed from the Dewatering Building to the truck loading
station via progressive cavity pumps (one per centrifuge) and two force mains. Sec Table 4 for a
summary of the design criteria for the centrifuge feed pumps and polymer feed systems, and
Table 5 for the design criteria for the high solids centrifuges and accessories.
. JLlN-23-8008 09:14A FROM: ^^TED WATER
, . , .JLIN-aS-EOOS 09:15A FROM:P.3^9195448590 70:95714718
TABLE 4
9
III
H'l’.xb i.hV btii’i'ioN
I ■ 1 I
DESIGN CRI fl-RIA
HIGH SOLIDS CENTRIFUGE FEED PUMPS AND POLYMER FEED SYSTEMS
DESIGN CRITERIA
980 gal./month; 3 (300 gal,) totes
1,810 gal./month; 6 (300 gal.) totes
Two 3,000 gal. tanks
73
145,000
2,318,500 gal, 0.75% TS
156 gpm
40 -175 gpm
14.5 dry tons/d
20 Ibs/D’P’
Continuous solution, mix/feed; emulsion type
40%
0,5%
2 (one per centrifuge)
Dosigru 3.8 gph; maximum 5.0 gph (w/10:l turndown)
Approximately 112'
ProgreKsivu Cavity; Positive Displacement
2
7-1/2
15
Variable Frequency Drives
2 units (1 per tank suction)
Magnetic
2 (1 per feed pump)
40 — 175 gpm
4"
Biosolids Production
Tons/Produrtion Week Dry Weight
Lbs/Pmduction Week Dry Weight
Gal/Production Week (WAS)
J Ugh Solids Cintrifuge Sludge Feed Pumps/Grinders
Design Flow Rate ((S’ 0.75% T$)
Design Flow Operating Range
(W 0.75 - 3% TS)
TDH ® 156 gpm thru 4" Discharge Piping
Feed Pump Type
Number of units
Horsepower Requircmcnt/unit
Total Connected HP
Control
In-line Grinders
Provide layout for one additional
future feed pump
High Solids Centrifuge Polymer Feed and Storage System
Biosolids Loading Rate/Production Day
Active Polymer/Ton Dry Solids
Polymer Feed System Type
Emulsion Active Polymer Cone.
Polymer Feed Solution Cone
Number of Polymer Feed Units
Polymer Feed Ratc/Unit
Provide layout for one additional
future polymer unit
Initial Year Polymer Required/Month
Design Year Polymer Required/Month
Alternate Bulk Storage System
High Solids Centrifuges Sludge Feed Flowmeter
Type
Number of Units
Flow Range
Meter Size
Provide layout for one additional
future flowmeter________________
(1) Based on operating 5U weeks per year (production weeks) at 12 MCD.
(2) Andritz centrifuge pilot study for Triangle WWTP recommends Polydync C-62b2 polymer.
^TED WATER
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PROPOSED SITE PLAN
DURHAM COUNTY
NORTH CAROLINA
TRIANGLE WASTEWATER TREATMENT PLANT PHASE III
OEWA TERNG
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RECTVCW THIS METHOD RESULTS IN NAD 63 (COPS 96) POSITIONS
ANO NAVO 88 (MSL) ELEVATIONS USING THE CONTINUOUSLY
CPCTATTNG STATIONS MAINTAINED BY NORTH CAROUNA GEODETIC
SURVEY
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DURHAM COUNTY
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TRIANGLE WASTEWATER TREATMENT PLANT
_______________PHASE III______________
DEWATERING FACILITY
DA PE;_______
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CHECKED
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01471-0004
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THE GRID COORDINATES SHOWN ON THIS MAP WERE DERIVED BY
VRS (VIRTUAL REFERENCE STATION GPS USING A DUAL FREQUENCY
RECEIVER. THIS METHOD RESULTS IN NAD 83 (CORS 96) POSITIONS
ANO NAV0 88 (MSL) ELEVATIONS LSINC THE CONTINUOUSLY
OPERATING STATIONS MAINTAINED 8Y NORTH CAROLINA GEODETIC
SURVEY.
^MXIM&CRFED
1730 Varsity Drive. Suite 500
Phone: [phone]. Fax: [phone]
Raleigh, North Carolina 276G6
June 15, 2008
August 30, 2008
• Submit to State for A-T-C
September 15, 2008
• Receive A-T-C from State
March 15, 2009
• Advertise Project.
March 23, 2009
• Receive Bids
April 30, 2009
• Award Construction Contracts May 31, 2009
• Execute Construction Contracts July 31, 2009
• Notice to Proceed for Construction,August 7, 2009
November 7, 2010
L
REVISED PROJECT SCHEDULE
June 2008
DURHAM COUNTY
TRIANGLE WASTEWATER TREATMENT PLANT
BIOSOLIDS PROCESS TRAIN IMPROVEMENTS
• Construction Completion
• Submit NPDES Permit Modification Request....
• Receive Approved NPDES Permit Modification
DURHAM COUNTY TRIANGLE WASTEWATER TREATMENT PLANT
BIOSOLIDS MANAGEMENT PLAN UPDATE
DURHAM COUNTY, NORTH CAROLINA
June 13, 2008
^7,
2 0 20C8
n-
Municipal Contact:Prepared By:
MCKIM<&CREED
Mr. Joseph Pearce, PE
Durham County
120 East Parrish St.
Durham, NC 27701
[phone]
Mr. David M. Heiser, PE
McKim & Creed, P.A,
1730 Varsity Drive
Raleigh, NC 27606
[phone]
PHASE III - BIOSOLIDS FACILITY BASIS OF DESIGN
^996000999,
13484
^3^
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Introduction
Design Influent Wastewater Characteristics and Design Biosolids Production Quantities
1
Durham County has decided to proceed with contract composting as an interim step for
Phase III in their biosolids management program. This interim step shall provide for liquid
storage of waste activated sludge (WAS), on-site dewatering, and a truck loading facility for
dewatered sludge which will allow for contract hauling to a permitted composting facility. The
decision to proceed with contract composting was not to preclude the County from ultimately
providing for heat drying or other stabilization option in the future.
The design influent wastewater characteristics and design biosolids production quantities are as
contained in McKim & Creed's Phase III Biosolids Management Systems Engineering
Alternative Analysis Amendment No. 2 dated July 10, 2007 and as summarized below in Tables
1 and 2. The biosolids production quantities shown in Table 2 are calculated using both the
biological solids yield factor of 0.70 pounds per pound of BODs loading in the plant influent
calculated from the current WAS production at the plant, and the design solids yield factor of
0.95 pounds per pound of BODs loading.
TRIANGLE WASTEWATER TREATMENT PLANT
DURHAM COUNTY
BIOSOLIDS MANAGEMENT PLAN UPDATE
CONTRACT COMPOSTING ALTERNATIVE
PHASE III - BIOSOLIDS FACILITY
BASIS OF DESIGN
JUNE 13, 2008
TABLEI
36
2
DURHAM COUNTY TRIANGLE WWTP
DESIGN INFLUENT WASTEWATER CHARACTERISTICS
200
20,020
25
2,500
4
400
Average Daily Flow (MGD)
' Peak Hourly Flow (MGD)
I Organic Loading (BOD5)
(mg/1)
(lbs/d)
Total Suspended Solids
(mg/1)
(lbs/d)
Total Nitrogen
(mg/1)
(lbs/d)
180
18,020 ;
I
40
4,010
12
. NH3-N
(mg/l)
(lbs/d)
Total Phosphorus
(mg/l)
(lbs/d)
TABLE 2
DESIGN BIOSOLIDS PRODUCTION QUANTITIES
wa'J 'CfiTT a;.-
12.0 MGD12.0 MGDAVERAGE DAILY INFLUENT FLOW
20,020 Ibs/d20,020 Ibs/dORGANIC LOADING (BODs)
16, 480 wet tons/yr12, 330 wet tons/yr
20,600 cy/yr15,415 cy/yr
3
WASTE ACTIVATED SLUDGE (WAS) PRODUCTION
@ 0.5% TS (@ 12 MGD)
© 0.75% TS (@ 12 MGD)
EQUIVALENT DEWATERED BIOSOLIDS CAKE
PRODUCTION FROM CENTRIFUGE DEWATERING
Weight @ 22% TS
0.70 Ibs/lb BOD?
8.5 ibs/lb TP
356,500 gals/d
237,600 gals/d
0.95 lbs/ lb BODs
8.5 Ibs/lb TP
sii
476,400 gals/d
317,600 gals/d
BIOSOLIDS YIELD
Biological Solids (2)
Chemical Solids (phosphorus)(l)
BIOSOLIDS PRODUCTION
Biological Solids
Chemical Solids (phosphorus),1)(3)
Total Biosolids Production
2,560 dry tons/yr
155 dry tons/yr
2,715 dry tons/yr
3,470 dry tons/yr
155 dry tons/yr
3,625 dry tons/yr
♦17 j ■■ I* - I iWi
Bl
_____Volume @ 22% TS
(1) Based on an average influent phosphorus concentration of 4 mg/1.
(2) Includes biosolids yield from carbonaceous oxidation, as well as biological yield associated with biological nutrient removal
(both nitrogen and phosphorus).
(3) Assumes phosphorus concentration can be effectively reduced to 1.0 mg/1 biologically. The biosolids generated as a result of
biological phosphorus removal are accounted for in the Biological Solids category. The chemical solids listed assume sodium
aluminate will be utilized to reduce residual TP concentration from 1.0 mg/1 to <0.28 mg/1
Operation Overview
area
room
4
The new structures, liquid WAS storage. Dewatering Building and truck loading station, shall
be located within the "footprint" of the existing southern aeration basin. The new structures
shall be arranged to facilitate the future addition of a dryer building and additional liquid WAS
storage, minimizing impact on the contract composting operations.
The existing southern clarifier shall be modified to accept backwash water from the existing
filters and centrate from the dewatering facilities for flow equalization and pumping back to the
BNR process influent distribution box.
The unthickened WAS (approximately 0.75% TS) will be pumped via variable speed
progressive cavity dry-pit pumps (centrifuge sludge feed pumps) to the dewatering building
housing the high solids centrifuges. The centrifuge sludge feed pumps are anticipated to be
housed below grade to allow for a flooded pump suction and to allow complete emptying of the
liquid storage tanks.
It is anticipated that the high solids centrifuges will produce a 22% solids sludge. The
dewatered sludge will be conveyed to the truck loading station. The truck loading station shall
provide space for dual truck loading and shall be located adjacent to the Dewatering Building.
The Dewatering Building will be a one-story facility with a basement area located near the
liquid WAS storage tanks and will house the following components:
Waste activated sludge (WAS) will be wasted from the existing RAS/WAS pumping station to a
WAS liquid storage tank. The tank is proposed as a 1.0 MG two cell (0.5 MG each cell) common
wall cast-in-place concrete storage tank. The tank will be provided with an aeration and mixing
system in each cell.
> Centrifuge area
> Polymer feed and storage
> Office/control room
> Test sample/preparation
> Electrical room
> Single restroom/shower
> Sludge feed pump area
The contracting composting operation will allow the County to manage biosolids in a more
routine, consistent, and efficient manner than the current process of utilizing the existing sludge
lagoon, as well as allow for a future expansion to a heat drying process.
Design Criteria
Waste Activated Sludge Pumping and Storage
5
Each tank will be provided with level indication so the operators will know the liquid levels in
each tank to assist them with selecting which tank to utilize for wasting. Separate float switches
will be installed in each tank to cut off the mixers and aerators in that tank should its water level
fall to a specified elevation below which the mixers and aerators will not be effective.
Each of the two tanks will be equipped with independent submersible aerators and mixers that
will be used to keep the tank contents fully mixed, as well as to provide for aeration to keep the
dissolved oxygen at an acceptable level. Two mixers and two submersible aerators will be
installed in each tank.
The aeration and mixing system for the sludge holding tanks will be sized for aeration and
mixing as a "nursing" tank for the centrifuges, and not to provide for aerobic digestion.
WAS is pumped from the existing RAS/WAS Pump Station that serves four flocculating, high-
rate center-feed clarifiers and currently discharged to the existing sludge lagoon. The discharge
of the WAS pumping station will be diverted to the new liquid WAS storage tanks via an
extension of the existing force main. WAS at approximately 0.5% TS concentration (initial year)
and 0.75% TS concentration (starting in 2012) will be pumped (via the existing submersible
WAS pumps located adjacent to the new clarifiers) to one of two new 500,000 gallon sludge
holding tanks (1.0 million gallons total storage capacity). WAS flow will be metered via the
existing in-line magnetic flow meter located at the WAS pump station. The WAS flow is
continuously monitored and totalized via the Plant SCADA system. Scum from the final
clarifiers will also be pumped to these storage tanks.
Floating decanters with submerged weirs will be used (one per tank) to withdraw supernatant
from the tanks at the maximum water level down to approximately ten feet of water depth.
This will provide an operating range of approximately twelve feet. Supernatant from these
decanters will be routed to the equalization basin.
The liquid WAS storage tank will be a cast-in-place concrete structure with common wall
construction for the two cells. The western end of the structure, walls, and footing will be
provided with water stops and dowel inserts to accommodate the future 1.0 MG storage
expansion if needed. The tanks will have open tops and no odor control system will be
provided. See Table 3 for a summary of the design criteria for the sludge holding tanks.
Using the current solids yield factor for biological solids, the 1.0 MG total storage volume
provides 4.2 days storage of liquid storage capacity at WAS design year (12 MGD) production
(237,600 gpd @ 0.75% TS) or 8.4 days storage at 6.0 MGD. Using the design solids yield factor, 3
days storage of liquid sludge at 12 MGD plant flow will be provided, or 6 days storage at 6
MGD.
TABLE 3
WASTE ACTIVATED SLUDGE HOLDING TANKS
6
______________
WASTE ACTIVATED SLUDGE LIQUID STORAGE SYSTEM
DESIGN CRITERIA
Floating Style Dissolved Oxygen Sensors
0.1 mg/1 to 2.0 mg/1
33'
95'
24'
________________2T
Cast in place concrete
Pressure Transducer
1 unit/cell
Submersible Aerators
Two Per Tank
75 lbs Oz/hr (Total)
1 Float Switch/Cell
Timers and/or Dissolved Oxygen Levels
Floating; submerged weir
1 unit/cell
500 gpm (minimum 4 hour cycle)
Motorized plug valve
12' (10 to 22 foot SWD)
Positive flow indicator (1/cell)
Submersible Mixers
Two Per Tank
1 Float Switch/Cell
Total Volume___________________________________
It of Independent Cells
Volume per Cell (MG)______________ ________
Dimensions (each cell)
Width
Length
Wall Height
_____Max Liquid Depth ____________________
Materials of Construction
Provide for expansion by addition of two future cells
Mixing System
Type
Number of Mixers
Low Level Cut Off
Aeration System
Type
Number of Aerators
Oxygen Transfer Rate Required
Low Level Cut Off
Aeration Control
Aeration Monitoring
Type
DO Concentration Range
Decanters
Type
Number of Units/Cell
Maximum Decant Rate
Control
Minimum Vertical Travel Required
Flow Detection
Level Indication
Type
Number of Units
1.0 MG
2
0.50
:: ‘
Centrifuge Dewatering
7
Due to the wash down, flushing and energy requirements for startup and shutdown, it is
recommended that the County plan to operate the dewatering system continuously, 24 hours
per day for the required total number of hours each week (rather than starting and stopping the
system for limited periods during the week).
The suction and discharge piping for the sludge feed pumps will be arranged to allow for the
addition of a third (future) sludge feed pump.
The suction header for the feed pumps shall be furnished with two in-line grinders (one per
tank suction line). The grinder units will allow for grinding of material in the waste activated
sludge that may have reformed larger solids in the holding tanks.
The waste activated sludge will be pre-conditioned with emulsion polymer injected to the feed
sludge via a flange-mounted polymer injection ring to assist in achieving a design dewatered
cake solids concentration between 20% and 22% TS. Sludge cake produced in the dewatering
process will be conveyed to the truck loading station. Centrate will be conveyed to the new
equalization basin via a new gravity sewer, and blended and equalized with other process
wastestreams before being pumped back to the BNR process influent distribution box.
Liquid waste activated sludge will be pumped from each of the two sludge holding tanks to a
new high solids centrifuge dewatering operation. Two progressive cavity dry-pit pumps (one
per centrifuge) will be used to feed the two centrifuges. Each pump will be equipped with a
variable frequency drive to allow the operator to optimize the dewatering operation. The feed
pumps will be installed in the lower level of the Dewatering Building and will be manifolded
such that the pumps can draw suction from either of the two WAS liquid sludge holding tanks
via separately valved inlets. In addition, the discharge from the two pumps will be manifolded
to allow them to feed either of the two centrifuges.
The design hydraulic loading capacity for each centrifuge is 156 GPM at a feed sludge
concentration of 0.75% TS. During the initial year (6 MGD), it is anticipated that the dewatering
system will operate for 62 hours per week (2.6 twenty-four hour days) with two units operating,
but will need to increase to run 124 hours per week (5.2 twenty-four hour days) with two units
operating to accommodate the design year (12 MGD) loadings. The centrifuge sizing was
generally designed to accommodate "design year" loadings in 5.2 twenty-four hour periods
The centrifuges will be installed inside the proposed new Dewatering Building located adjacent
to the sludge holding tanks. The new building will also house the new mix/feed emulsion
polymer feed systems, electrical equipment, control panels and accessory equipment.
As noted previously, for the initial year of operation two feed pumps, two polymer systems and
two centrifuge units will be installed in the new facilities.
8
each week, 50 weeks per year. This provides time for maintenance and repair each week, and
provides time to do more extensive maintenance during a scheduled two week shutdown each
year.
The dewatered sludge cake will be conveyed from the Dewatering Building to the truck loading
station via progressive cavity pumps (one per centrifuge) and two force mains. See Table 4 for a
summary of the design criteria for the centrifuge feed pumps and polymer feed systems, and
Table 5 for the design criteria for the high solids centrifuges and accessories.
TABLE 4
9
HIGH SOLIDS CENTRIFUGE FEED PUMPS AND POLYMER FEED SYSTEMS
DESIGN CRITERIA
980 gal./month; 3 (300 gal.) totes
1,810 gal./month; 6 (300 gal.) totes
Two 3,000 gal. tanks
73
145,000
2,318,500 gal. @ 0.75% TS
156 gpm
40 -175 gpm
14.5 dry tons/d
20 Ibs/DT®
Continuous solution, mix/feed; emulsion type
40%
0.5%
2 (one per centrifuge)
Design; 3.8 gph; maximum 5.0 gph (w/10:l turndown)
Approximately 112'
Progressive Cavity; Positive Displacement
2
7-1/2
15
Variable Frequency Drives
2 units (1 per tank suction)
Magnetic
2 (1 per feed pump)
40 -175 gpm
4"
pl?
Biosolids Production
Tons/Production Week Dry Weight
Lbs/Production Week Dry Weight
Gal/Production Week (WAS)_____________
High Solids Centrifuge Sludge Feed Pumps/Grinders
Design Flow Rate (@ 0.75% TS)
Design Flow Operating Range
(@ 0.75-3% TS)
TDH @ 156 gpm thru 4" Discharge Piping
Feed Pump Type
Number of units
Horsepower Requirement/unit
Total Connected HP
Control
In-line Grinders
Provide layout for one additional
_____future feed pump__________________________
High Solids Centrifuge Polymer Feed and Storage System
Biosolids Loading Rate/Production Day
Active Polymer/Ton Dry Solids
Polymer Feed System Type
Emulsion Active Polymer Cone.
Polymer Feed Solution Cone
Number of Polymer Feed Units
Polymer Feed Rate/Unit
Provide layout for one additional
future polymer unit
Initial Year Polymer Required/Month
Design Year Polymer Required/Month
Alternate Bulk Storage System
High Solids Centrifuges Sludge Feed Flowmeter
Type
Number of Units
Flow Range
Meter Size
Provide layout for one additional
future flowmeter__________________________
(1) Based on operating 50 weeks per year (production weeks) at 12 MGD.
(2) Andritz centrifuge pilot study for Triangle WWTP recommends Polydyne C-6262 polymer.
TABLE 5
10
HIGH SOLIDS CENTRIFUGES AND ACCESSORIES
DESIGN CRITERIA
50
5.2
24
1,170 (Dry Weight)
18,720 @ 0.75% TS
5,494 @ 22% TS
412 @ 22% TS
2 duty
0.75% - 2.0%
20% - 22%
95%
145,000 Ibs/wk, Dry Weight
660,000 Ib/wk, @ 22% TS
132,000 Ib/day, @ 22% TS
412 CY/wk, @ 22% TS
Progressive Cavity, Positive Displacement
2 (1/Centrifuge)
15 HP
5.5 GPM
200 psi (Max.)
Variable Frequency Drives
Pump Base Load Cells
"Run Dry" and High Pressure
High Solids Centrifuges
Required Centrifuge Capacity (2 units operating)
» Production Weeks/Year
# Production Days/Week
# Production Hrs/Day
Design Throughput (Ibs/Hour)
Design Throughput (gallons/Hour)
Design Cake Production (Ibs/Production Hour)
Design Cake Production (CY/Production Week)
Number of Centrifuge Units
Influent Solids Concentration
Design Cake Solids Concentration
Design Solids Capture Efficiency
Provide layout for one additional future centrifuge_________
High Solids Centrifuge Accessories ________________
Sludge Cake Pumps
Solids produced/wk
Wet cake produced/production wk
Wet cake produced/production day
Wet cake produced/production week
Pump Type
Number of Units
Horsepower Per Pump
Design Capacity
Discharge Pressure
Pump Control
Centrifuge-to-Pump Speed Control
Pump Discharge Protective Devices
Provide layout for one additional future sludge cake pump
1
Truck Loading Station
Dewatering Building
11
The County will contract with a local company to provide the truck trailers, cabs and
manpower to haul the dewatered cake sludge from this plant to a permitted composting facility.
A truck loading station will be provided for the off-loading of the dewatered sludge. The
loading station will be located adjacent to the Dewatering Building and will be furnished
without truck scales. The dewatered sludge will be conveyed from the centrifuge area via
progressive cavity cake pumps that will discharge to two force mains which will transport the
sludge cake to the truck loading station.
The truck loading station will have a roof system which will match the Dewatering Building.
The lower level shall be open on all four sides. The truck bay areas shall be designed to contain
spillage, and shall be sloped to a trench drain system that will interconnect with the gravity
drain line to the equalization basin. The truck loading station floor shall be concrete in the truck
bay area.
The lower wall section shall be brick/block, and depending on the final eave height of the
building, the upper wall section may be metal siding to match the construction of the existing
administration/maintenance building. The roof system shall be standing metal seam with color
to match the existing administration/maintenance building. It is anticipated that the building
area for the dewatering operations will be approximately 4,850 sf (63' x 77').
The truck loading station will have two truck bays and will be approximately 30 ft. wide by 52
ft. long. Three motor-operated swing arm assemblies, each with an in-line knife gate valve, will
be installed near the ceiling, and will be capable of swinging to either truck bay to discharge
sludge cake to the trucks.
• Centrifuge area
• Polymer feed and storage area
• Office/control room
• Test sample/preparation room
• Electrical room
• Single restroom/shower room
The Dewatering Building contains two primary areas; one for dewatering operations and one
for housing the centrifuge feed pumps to drain the liquid WAS from the storage tanks. The
dewatering area will be a single story, slab on grade building housing the following
components:
for a forklift truck into the
In-Plant Flow Equalization and Pumping Facility
12
A large concrete pad shall be provided on two sides of the building for unloading/loading
equipment and supplies, along with a ramp to allow access for a forklift truck into the
dewatering building.
The existing southern clarifier will be converted to an Equalization (EQ) Basin to flow equalize
sidestream/retum flows from the existing effluent filters, the existing chemical containment
area, decant from the liquid WAS holding tanks, and centrate from the dewatering facilities.
The office, sample room, restroom and electrical room will be conditioned space. Tire
remainder of the dewatering area shall be provided with LP gas heaters and ventilation only.
Vent louvers shall be exhausted to the exterior of the building, but no odor control is to be
provided.
The existing dry pit RAS/WAS pump station located adjacent to the clarifier will be abandoned
and filled with sand. A new submersible pump station wetwell will be installed adjacent to the
EQ Basin on the existing 24" influent pipe to the clarifier. Two new submersible pumps with
variable frequency drive units will be provided to pump equalized flow back to the BNR
process influent distribution box.
One (1) submersible mixer and two (2) submersible aerators shall be installed in the converted
equalization basin to provide for mixing to minimize settlement of solids, and for some aeration
to keep the dissolved oxygen at an acceptable level. The basis of design for the aerators is an
oxygen transfer rate (required) of 40 lbs. Os/hr (total for both aerators).
A storage area will be located between the dewatering building and the liquid WAS storage
tanks. This area will provide floor space to accommodate chemical totes and other equipment
storage, as well as a covered area to park the forklift truck when not in use. The floor space for
the storage area, including the stairwell to the basement and the covered area, will be
approximately 1,850 sf (24' x 77').
The centrifuge area will be provided with a monorail/hoist system to allow for removal of the
units. The polymer storage area shall be laid out with a recessed floor in lieu of raised curbs for
chemical leakage containment to allow for easier access utilizing a fork lift truck.
A basement area will be provided beneath the storage area floor to house the in-line grinders
and sludge feed pumps. Two pumps will be provided with floor space to accommodate one
additional future feed pump. A monorail/hoist system will be provided to allow for removal of
the basement equipment through an access hatch in the storage area floor above. Floor space
for the equipment area, not including the stairwell, will be approximately 1,335 sf (23 x 58 ).
I
June 17, 2008
RE:
Dear Mr. Vinzani:
120 E. Parrish Street. Law Bldg., 1st Floor, Durham, N.C. 27701 [phone] Fax [phone]
Equal Employment/Affirmative Action Employer
Triangle Wastewater Treatment Plant
Durham County, North Carolina
NPDES Permit No. NC0026051
Mr. Gil Vinzani. P.E.
Supervisor, Eastern NPDES Program
NCDENR - DWQ
1617 Mail Service Center
Raleigh. NC 27699-1617
COUNTY OF DURHAM
ENGINEERING DEPARTMENT
r*"
The Phase III Biosolids Facility will provide for liquid waste activated sludge storage, a
dewatering facility and truck loading for a contract composting operation. The attached Basis of
Design documents the design elements for Phase III. Based on the current project schedule.
Phase III would be placed on-line at the end of 2010.
Please consider this request for a MINOR modification of the above-referenced NPDES permit
for the Triangle Wastewater Treatment Plant in Durham County. In accordance with your
telephone conversations with Dave Heiser of McKim & Creed earlier this year, enclosed
herewith is a site plan for the proposed Phase III Biosolids Facility, a revised completion
schedule, and a Biosolids Management Plan Update - Basis of Design for review. No increases
in flow or pollutant loads, changes to permit effluent limits, or modifications to the pennitted
facility treatment processes are included in this request - simply a modification to the method of
biosolids management as listed in the NPDES Permit.
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n JUN 20 2008
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Encl:
cc:
JP/ds
S:\Utility Division\Utilities.. Front Desk 2008\6-16-08 Vinzam Letter doc
Mr. Gil Vinzani, P.E.
June 17, 2008
Page 2
Mack Wiggins, NCDENR Raleigh Regional Office
Dave Heiser, PE, McKim & Creed, PA
Bryan Blake, PE, McKim & Creed, PA
Sincerely,
/AO
// J(/sepn Pearce, P.E.
Utility Division Manager
Durham County Engineering Department
We trust you will find this information acceptable, and will be able to modify the current NPDES
Permit accordingly. If you have any questions, or require any additional information, please
contact either me or Dave Heiser, PE, at McKim & Creed (919-233-8091).
Site Plan for the Proposed Phase III
Biosolids Facility - Basis of Design
Revised Completion Schedule
Biosolids Management Plan Update
^\NArfy Michael F. Easley. Governor
June 20, 2008
Subject:
Dear Mr. Pearce:
Sincerely,
Cc;
An Equal Opportunity/Affirmative Action Employer - 50% Recycled/10% Post Consumer Paper
The Division of Water Quality, Point Source Branch, acknowledges receipt of your permit modification request with
supporting information on June 20, 2008.
Please note at this time, processing permit applications can take al long as 60 - 90 days after receipt of a complete
application.
If you have any questions, please contact Maureen Crawford at 919-733-5083 ext. 538 or via email at
[e-mail]. If the reviewer is unavailable, you may leave a message, and they will respond
promptly.
PLEASE REFER TO THE ABOVE APPLICATION NUMBER WHEN MAKING INQUIRES ON THIS
PROJECT.
North Carolina Division of Waler Quality
Internet: www.ncwaterquality.org
Central File
Raleigh Regional Office Surface Water Protection Section
Permit application file NC002605I
Laurie Singleton
Point Source Branch
William G. Ross Jr.. Secretary
North Carolina Department of Environment and Natural Resources
Phone [phone]
Fax [phone]
Coleen H. Sullins, Director
Division of Water Quality
1617 Mail Service Center Raleigh, NC 27699-1617
Location: 512 N. Salisbury St. Raleigh. NC 27604
Acknowledgement of Permit Modification Request
Triangle WTP
NPDES Permit NC0026051
Durham County
Customer Service
1-877-623-6748
CO/
o1
The reviewer will perform a detailed review and contact you with a request for additional information if necessary. To
ensure the maximum efficiency in processing permit applications, the Division requests your assistance in providing a
timely and complete response to any additional information requests.
NoithCarolina
Naturally
JOSEPH PEARCE PE
UTILITY DIVISION MANAGER
DURHAM COUNTY ENGINEERING DEPT
120 E PARRISH ST LAW BLDG 1st FLR
DURHAM NC 27701
Michael F. Easley. Governor
June 24, 2008
Re:
Dear Mr. Pearce:
Sincerely,
Cc:
NprthCarolina
Jyaturally
An Equal Opportunity/Affirmative Action Employer-50% Recycled/10% Post Consumer Paper
North Carolina Division of Water Quality
Internet: www.ncwaterqualitv.org
Central File
Raleigh Regional Office Surface Water Protection Section
Pennit application file NC0026051
Coieen H. Sullins, Director
Division of Water Quality
PLEASE REFER TO THE ABOVE APPLICATION NUMBER WHEN MAKING INQUIRES ON THIS
PROJECT.
Change of Reviewer for Permit Modification Request
Triangle WTP
NPDES Permit NC0026051
Durham County
Customer Service
1 -877-623-6748
L/urie Singleton
Point Source Branch
If you have any questions, please contact Vanessa Manuel at 919-733-5083 ext. 532 or via email at
[e-mail] . If the reviewer is unavailable, you may leave a message, and she will respond promptly.
u-
■ X
£?/1)11 IfJ
JOSEPH PEARCE PE
UTILITY DIVISION MANAGER
DURHAM COUNTY ENGINEERING DEPT
120 E PARRISH ST LAW BLDG 1st FLR
DURHAM NC 27701
The reviewer has been changed to Vanessa Manuel who will perform a detailed review and contact you with a request
for additional information if necessary. To ensure the maximum efficiency in processing permit applications, the
Division requests your assistance in providing a timely and complete response to any additional information requests.
William G. Ross Jr., Secretary
North Carolina Department of Environment and Natural Resources
The Division of Water Quality, Point Source Branch, would like to inform you of a change in your reviewer of your
permit modification request, received on June 20, 2008.
1617 Mail Service Center Raleigh. NC 27699-1617 Phone [phone]
Location: 512 N. Salisbury St. Raleigh. NC 27604 Fax [phone]
Michael F. Easley, Governor
June 27, 2008
(f
jUN 2 720®
L kAflCtn ftSubject:
Dear Mr. Pearce:
Sincer
Cofeen H. Sullins
Attachment
Cc:
An Equal Opportunity/Affirmative Action Employer - 50% Recycled/10% Post Consumer Paper
1617 Mail Service Center, Raleigh, North Carolina 27699-1617
512 N. Salisbury St., Raleigh, North Carolina 27604
Phone: [phone]/FAX: [phone]/Internet: www.ncwaterqualitv.org
Joseph Pearce, P.E.
County of Durham
120 E. Parrish Street, Law Bldg.
Durham, NC 27701
The Division of Water Quality has received and reviewed your permit modification request dated
June 17, 2008, for Triangle WWTP. In response to your request, the subject NPDES permit has
been modified to reflect the following:
■ Additional language has been added to the Supplement to Permit Cover Sheet to reflect
the facility’s proposed contract composting operation and changes to the Biosolids
Management Plan.
Accordingly, we are forwarding herewith the attached modified NPDES permit. Please insert
the attached permit page into your permit and discard the old one.
This permit modification is issued pursuant to the requirements of North Carolina General
Statute 143-215.1 and the Memorandum of Agreement between North Carolina and the U.S.
EP A dated October 15, 2007 (or as subsequently amended).
dwq/swp - RRO
DWQ/SWP - Central Files
NPDES Files
If you have any questions regarding any of the above, then please feel free to contact Vanessa
Manuel at 919/733-5083, extension 532.
William G. Ross, Jr., Secretary
Coleen H. Sullins, Director
OneNorth Carolina Naturally
NCDENR
North Carolina Department of Environment and Natural Resources
Division of Water Quality
ft
j 11
NPDES Permit Modification
Triangle Wastewater Treatment Plant
NPDES Permit NC0026051
Durham County
Permit NC0026051
SUPPLEMENT TO PERMIT COVER SHEET
Durham County is hereby authorized to:
Minor Permii Modification: June 27, 2008
2. Discharge from said treatment works (via Outfall 001) into Northeast Creek, a Class WS-IV
NSW water in the Cape Fear River Basin, at the location specified on the attached map.
1. Continue to operate an existing 12.0 MGD wastewater treatment facility located south of
Durham at the Durham County Triangle WWTP off NC Highway 55 in Durham County.
The facility includes the following treatment components:
All previous NPDES Permits issued to this facility, whether for operation or discharge are hereby revoked.
As of this permit issuance, any previously issued permit bearing this number is no longer effective.
Therefore, the exclusive authority to operate and discharge from this facility arises under the permit
conditions, requirements, terms, and provisions included herein.
Mechanical fine screens
Mechanical grit removal
Parshall flume
Influent pump station
Three 5-stage BNR trains
Four secondary clarifiers
Five tertiaiy sand filters
Ultraviolet disinfection
Post aeration
Sludge lagoons
Waste and return activated sludge pumping system
Methanol, potassium hydroxide, and sodium hypochlorite storage and feed systems
Liquid waste activated sludge storage (projected service date is the end of 2010)
Dewatering facility (projected service date is the end of 2010)
Truck loading for contract composting operation (projected service date is the end
of 2010)
July 14, 2008
Subject:
Dear Mr. Pearce:
The Durham County Triangle WWTP currently accepts up to 6 MOD of wastewater from the Town of
Cary. Upon completion ot the Western Wake wastewater treatment facility, the flow received from
Cary will be transferred to the new treatment plant.
Joseph R. Pearce, Jr., PE
POTW Director
Durham County
120 E. Parrish Street, Law Bldg., First Floor
Durham, NC 27701
&
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{DENR1
The Pretreatment, Emergency Response and Collection Systems (PERCS) Unit and Raleigh Regional
Office have reviewed your proposed alternative method for flow allocation for the Durham County
collection system. The Division received this proposal on June 17, 2008.
Michael F. Easley, Governor
William G. Ross Jr., Secretary
North Carolina Department of Environment and Natural Resources
Coleen S. Sullins, Director
Division of Water Quality
The Division will accept this method ot flow tracking while the Western Wake wastewater treatment
facility is under construction. The Division's Flow Tracking/Acceptance for Sewer Extensions
methodology requires that flow reconciliation be conducted once per quarter once the wastewater flow
allocated reaches 80% ot the facility's permitted flow. The data provided by Durham County indicates
the current percentage to be at 89%. The SIU flow will be based on the highest monthly average flow
during the previous 12 months and will be reconciled once per quarter and submitted to the Raleigh
Regional Office. Within 3 months of the start-up of the Western Wake WWTP, the Durham County
flow reconciliation must be resubmitted using the allocated SIU flows.
5?/ > I
1617 Mail Service Center Raleigh, NC 27699-1617
Location: 512 N. Salisbury St. Raleigh, NC 27604
””””—'”””~” NophCarolina
North Carolina Division of Water Quality 1617 Mail Service Center Raleigh, NC 27699-1617 Phone [phone] Customer Service
NC DWQ Internet: vyyyw.ncwaterqualitv.org Location: 512 N. Salisbury St. Raleigh, NC 27604 Fax [phone]
PERCS Unit Internet: http://h2o.enr.state.nc.us/percs/
An Equal Opportunity/Affirmative Action Employer - 50% Recycled/10% Post Consumer Paper
Collection System Flow Allocation Method Revision
Program: Durjjam County
NPDES #<7^00026051^^
Collection WQCS00038
WWTP: Durham County Triangle WWTP
Durham County proposes to use the highest monthly average flow for each Significant Industrial User
(SIU) instead of the permitted flow in their flow tracking calculations that determine the percentage of
the facility s permitted flow that is allocated. Essentially, this method is a flow reconciliation for the
Durham County SlUs, much like the flow reconciliation done when a subdivision is built out.
If you have any questions or comments, please contact Deborah Gore, at [phone] [email:
[e-mail]] or Matt Matthews, Point Source Branch Manager, at [phone] [email:
[e-mail]].
dg/durhamco_flow_tracking_method
Co: Central Files
Nadine Blackwell. Pretreatment Coordinator, United Water, 5926 Highway 55 East, Durham, NC, 27713
Sarah Morrison, PER.CS Unit
Cheng Zhang, Raleigh Regional Office
Barry Herzberg. Raleigh Regional Office
Sincerely,
b
Coleen H. Sullins
July 17, 2008
DEI'
Subject:
Dear Mr. Pearce:
The Pretreatment, Emergency Response and Collection Systems (PERCS) Unit and Raleigh Regional
Office have reviewed your proposed alternative method for flow allocation for the Durham County
collection system. The Division received this proposal on June 17, 2008.
Durham County proposes to use the highest monthly average flow for each Significant Industrial User
(SIU) instead of the permitted flow in their flow tracking calculations that determine the percentage of
the facility’s permitted flow that is allocated. Essentially, this method is a flow reconciliation for the
Durham County SIUs, much like the flow reconciliation done when a subdivision is built out.
The Durham County Triangle WWTP currently accepts up to 5 MOD of wastewater from the Town of
Cary. Upon completion of the Western Wake wastewater treatment facility, the flow received from
Cary will be transferred to the new treatment plant.
Michael F. Easley, Governor
William G. Ross Jr., Secretary
North Carolina Department of Environment and Natural Resources
Coleen S. Sullins, Director
Division of Water Quality
Joseph R. Pearce, Jr., PE
POTW Director
Durham County
120 E. Parrish Street, Law Bldg., First Floor
Durham, NC 27701
The Division will accept this method of flow tracking while the Western Wake wastewater treatment
facility is under construction. The Division’s Flow Tracking/Acceptance for Sewer Extensions
methodology requires that flow reconciliation be conducted once per quarter once the wastewater flow
allocated reaches 80% of the facility’s permitted flow. The data provided by Durham County indicates
the current percentage to be at 89%. The SIU flow will be based on the highest monthly average flow
during the previous 12 months and will be reconciled once per quarter and submitted to the Raleigh
Regional Office. Within 3 months of the start-up of the Western Wake WWTP, the Durham County
flow reconciliation must be resubmitted using the allocated SIU flows.
pZ.
co
> (L
Q XZ
1617 Mail Service Center Raleigh, NC 27699-1617
Location: 512 N. Salisbury St. Raleigh, NC 27604
One
NorthCarolina
North Carolina Division of Water Quality 1617 Mail Service Center Raleigh, NC 27699-1617 Phone [phone] Customer Service Z
NC DWQ Internet: www.ncwaterquality.org Location: 512 N. Salisbury St. Raleigh, NC 27604 Fax [phone]
PERCS Unit Internet: http://h2o.enr.state.nc.us/percs/
An Equal Opportunity/Affirmative Action Employer - 50% Recycled/10% Post Consumer Paper
Collection System Flow Allocation Method Revision (Corrected letter)
Program: Jhirhgm County
NPDES #<<22^0026051^
Collection#: WQCS00038
WWTP: Durham County Triangle WWTP
If you have any questions or comments, please contact Deborah Gore, at [phone] [email:
[e-mail]] or Matt Matthews, Point Source Branch Manager, at [phone] [email:
[e-mail]].
Sincerely,
Coleen H. Sullins
dg/d u rhamco_fl o w_tracki n g_met hod
Cc: Central Files
Nadine Blackwell. Pretreatment Coordinator, United Water, 5926 Highway 55 East, Durham, NC, 27713
Sarah Morrison, PERCS Unit .
Cheng Zhang, Raleigh Regional Office
Barry Herzberg. Raleigh Regional Office
MIG -
1 nt
August 4, 2008
Re:
Dear Mr. Vinzani:
To summarize, the ORC’s for the TWWP are as follows:
Please use the designation as listed above and detailed in the attached form to supersede any
information held by DWQ on this matter. Please change your records accordingly.
120 E. Parrish Street, Law Bldg., 1st Floor, Durham, N.C. 27701 [phone] Fax [phone]
Equal Employment/Affirmative Action Employer
Gil Vinzani
NPDES East Unit Supervisor, DWQ
1617 Mail Service Center
Raleigh, NC 27699-1617
Change in Operator in Responsible Charge (ORC) for Durham County Wastewater
Collection System, Triangle Wastewater Treatment Plant (TWWTP)
NPDES # NC0026051
COUNTY OF DURHAM
ENGINEERING DEPARTMENT
Name__________
Ralph Glenn Vance
Shawn Demetris Davis
Ron Ketteman
988558
22357
III
IV
Position__________________
Operator in Responsible Charge
(ORC)___________________
Back-Up ORC_____________
Back-Up ORC
Certificate No.
990409
Operator Grade
IV
iu) ’ ^1 X
iiRi
Please find attached the Water Pollution Control System Designation Form for the Durham County
Wastewater Collection System. Effective July 30th, 2008, Ronald Ketteman will serve as an
additional Back-Up ORC.
If you have any concerns, please give me a call at 919-560-7992
Encl: (1) Water Pollution Control System Designation Form
cc:
JRP/jld
Mack Wiggins, Environmental Specialist, DWQ
Jerry Rimmer, Supervisor TACU Unit, DWQ
Frankie Campagne, Project Manager, United Water
Glenn Vance, TWWTP ORC, United Water
Ronald Ketteman, Collection System ORC, United Water
Shawn Davis, Back-Up ORC, United Water
Glen E. Whisler, P.E., County Engineer
Richard G. Simms, Project Manager, United Water
Sincerely, ,
Joseph R. Pearce, P.E.
Utility Division Manager/POTW Director
General Information:
Permittee Owner/Officer Name:Durham County / Glen Whisler
Mailing Address: 120 East Parrish Street, Law Building Is1 Floor
City:Durham State:Zip: 27701 NC
Telephone Number [phone] Fax Number ( 919_) 560-0740
Signature: Date:
Facility Information:
Facility Name: Triangle WWTP
Permit Number: NC 0026051 County: Durham
! SUBMIT A SEPARATE FORM FOR EACH TYPE OF SYSTEM I
Mark (X) Type of Facility Grade Mark (X) Type of Facility
X 4
Operator in Responsible Charge:
Print Name: Ralph Glenn Vance
Certificate Type and Grade:Grade IVWastewater
Work Telephone: [phone]
Back-Up Operator in Responsible Charge:
Back-Up Operator in Responsible Charge:
Print Name: Shawn Demetris Davis Social Security #: 246-27-3490
Certificate Type and Grade:
Work Telephone: [phone]
Wastewater Plant
Physical/Chemical
Collection System
Spray Irrigation
Land Application
Water Pollution Control System Designation Form
WPCSOCC
NCAC 15A:08G .0201
Waste water Grade III Certificate #: 988558
Signature:
Certificate #: 990409
Signature:
Mail or Fax to:
Fax: [phone]
NC0026051
Back-Up Operator in Responsible Charge:
Print Name:Ron Ketteman
WW grade 4
Work Telephone: (_919J 544-8280 Signature:
Back-Up Operator in Responsible Charge:
Print Name:
Certificate Type and Grade: Certificate #:
Work Telephone: (J Signature:
Back-Up Operator in Responsible Charge:
Print Name:
Certificate Type and Grade: Certificate #:
Work Telephone: (J Signature:
Back-Up Operator in Responsible Charge:
Print Name:
Certificate Type and Grade: Certificate #:
Work Telephone: ( Signature:
Certificate#:
Permit Number:
Page 2
WPCSOCC
1618 Mail Service Center
Raleigh, N.C. 27699-1618
Certificate Type and Grade:
22357
al
September 21,2008
SUBJECT:
Dear Mr. Pearce:
1.
2.Review of the DMRs revealed consistent reporting of results as required by their permit.
3.
4.All logs and documentation was consistent and up to date.
5. All plant operators are certified for the field parameters ph, DO and Ammonia.
The Wastewater Treatment Plant site inspection:
3.
Raleigh Regional Office
Water Quality Section
fritest, Enco and Meritec do all analytical work. Enco does the priority pollutant analysis and
Meritec does analytical for mercury.
The Plant was configured as per the permit and is classified as class IV. Mr. Glenn Vance is
the head ORC and has a grade IV certification. The back-up ORC is Mr. Shawn Davis with a
grade III certification and Mr. Boyd McKenzie as project coordinator.
phone [phone]
facsimile [phone]
I. The influent flow meter was found to be operational and calibrated once a year. Ultrasonic flow
transmitter type. The effluent flow meter calibrated annually.
September 2, 2008 Compliance Evaluation Inspection
County of Durham
Triangle WWTP
Permit No: NC0026051
Durham County
1628 Mail Service Center
Raleigh. NC 27699-1628
Mr. Joseph R. Pearce, P.E.
Utility Division Manager/POTW Director
County of Durham
120 E. Parrish Street, Law Bldg., Is' Floor
Durham NC 27701
Customer Service
1-800-623-7748
4. The grit removal system is mechanical. This material was free of excessive odor. It is held on
site in the dumpster and ultimately taken to the landfill for disposal.
2. The influent pump station contained six pumps and two wet wells. All pumps were operable
and free of corrosion. Wet wells free of excessive grease. The visual bulb was blown during
the time of the inspection. A new bulb must be installed at your earliest.
> j L
Enclosed please find a copy of the Compliance Evaluation Inspection form for the inspection conducted by
Mack Wiggins of the Raleigh Regional Office on September 2, 2008. The assistance offered by Mr. Glenn
Vance, Boyd McKenzie, Shawn Davis and you Mr. Pearce was appreciated. The facility was found to be in
Compliance with permit NC0026051 at the time of this inspection.
in?
The bar screen is mechanical. The screen was free of excessive debris. All the screenings are
disposed of in the landfill. The bar screen appeared to be operating properly.
Michael F. Easley, Governor
William G. Ross Jr., Secretary
North Carolina Department of Environment and Natural Resources
1 a/a , A. << Coleen H. Sullins, Director
Division of Water Quality
5.
6.
7.
8.
9.
11. The effluent was clear with very little foam during the time of the inspection.
Sincerely,
The facility use ultraviolet disinfection. The facility has two banks. Only one bank needed in
service. Extra bulbs must be kept on site.
Five tertiary filters in line. Three of the five were in service during the time of the inspection.
Filters were free of solids and growth. Filters are backwashed every 20 days.
After the grit chambers is the influent return activated sludge chamber and raw wastewater
chamber at influent distribution to the biological nutrient removal. This chamber accepts
sodium aluminate feed to aid in removing metals.
Mack Wiggins
Environmental Specialist
Four secondary clarifiers with two in use. Clarifiers had a sidewall depth of ten feet with a
sludge blanket of two feet. Weirs are cleaned once a week.
cc: Durham County Health Dept.
Central Files
RRO File
Don Register, Regional Wastewater Treatment Plant Consultant, Fayetteville Regional Office
10. The facility utilizes a sludge holding lagoon. Sludge is removed by Bio-Nomics. Bio-Nomics
takes the sludge to an Earth Tec composting facility.
Please refer to the enclosed inspection report for additional observations and comments. If you or your staff
have any questions, please call me at [phone].
The BNR (Biological Nutrient Removal) consist of 5 stage process trains. Consist of the
anaerobic selector zone, methanol feed, 1st anoxic zone, 1st aerobic zone which accepts
potassium hydroxide as a pH adjuster, methanol feed, 2nd anoxic zone and 2nd aeration.
Methanol feed aid in denytrification by converting the nitrates to nitrogen gas. No dead spots in
aeration zone. Dissolved Oxygen level was 0.87 mg/1 during the inspection. Operator must
maintain a Dissolve Oxygen level of 1.0 to 3.0 mg/1. in the aeration zone.
1
ERA
NPDES
NC0026051
74
Entry Time/Date Permit Effective Date
06/11/0108/09/0211:00 AMTriangle WWTP
Exit Time/Date5926 NC Hwy 55 E Permit Expiration Date
Durham NC 27701 11/04/3008/09/0206:30 PM
Other Facility Data
Name, Address of Responsible Official/Title/Phone and Fax Number
Flow Measurement Records/Reports
Effluent/Receiving Waters
Section D: Summary of Finding/Comments (Attach additional sheets of narrative and checklists as necessary)
(See attachment summary)
Name(s) and Signature(s) of Inspector(s)Agency/Office/Phone and Fax Numbers Date
RRO WQ//919-791-4200/
Page #1
United States Environmental Protection Agency
Washington, D C. 20460
yr/mo/day
08/09/02
Form Approved.
OMB No. 2040-0057
Approval expires 8-31-98
Name(s) of Onsite Representative(s)/Titles(s)/Phone and Fax Number(s)
///
QA
72N
Date
Mack K Wiggins
j11
Water Compliance Inspection Report
Section A: National Data System Coding (i.e., PCS)
Fac Type
20IJ
Inspection Type
18H
73l I I
Agency/Office/Phone and Fax Numbers
i2i
Inspector
19IJ31.
------Reserved---------------------
75l I I I I I I 180
Transaction Code
’H 2 HJ
B1
71IJ
________________________________________________Section B: Facility Data
Name and Location of Facility Inspected (For Industrial Users discharging to POTW, also include
POTW name and NPDES permit Number)
I17
Section C: Areas Evaluated During Inspection (Check only those areas evaluated)
Operations & Maintenance
Self-Monitoring Program Sludge Handling Disposal Facility Site Review
Laboratory
Marvin Bernard Carter, 120 E Parrish St Law Bldg Durham NC 2 7701/lst°ntaCted
Back up ORC/919-560-0735/9195600740 No
Signature of Management Q A Reviewer
EPA Fofm 3560-3 (Rev 9-94) Previous editions are obsolete.
Remarks
21l I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I66
Inspection Work Days Facility Self-Monitoring Evaluation Rating
67| | 69 70| |
NPDES yr/mo/day 1
I1708/09/02NC0026051
Page #2
12l3I
Inspection Type
18. .I_£j_______________________
Section D: Summary of Finding/Comments (Attach additional sheets of narrative and checklists as necessary)
I11
OperationsJJi Maintenance Yes No NA NE
Is the plant generally clean with acceptable housekeeping?■

Comment:
Permit Yes No NA NE
(If the present permit expires in 6 months or less). Has the permittee submitted a new application?■
Is the facility as described in the permit?■
# Are there any special conditions for the permit?■
Is access to the plant site restricted to the general public?■
Is the inspector granted access to all areas for inspection?■
Comment:
Record Keeping Yes No NA NE
Are records kept and maintained as required by the permit?■
Is all required information readily available, complete and current?■
Are all records maintained for 3 years (lab. reg. required 5 years)?■
Are analytical results consistent with data reported on DMRs?■
Is the chain-of-custody complete?■
Dates, times and location of sampling
Name of individual performing the sampling
Results of analysis and calibration
Dates of analysis
Name of person performing analyses
Transported COCs
Are DMRs complete: do they include all permit parameters?■
Has the facility submitted its annual compliance report to users and DWQ?■
(If the facility is - or > 5 MGD permitted flow) Do they operate 24/7 with a certified operator on each shift?■
Is the ORC visitation log available and current?■
Is the ORC certified at grade equal to or higher than the facility classification?■
Is the backup operator certified at one grade less or greater than the facility classification?■
Is a copy of the current NPDES permit available on site?■
Page #3
Owner - Facility: Triangle WWTP
Inspection Type: Compliance Evaluation
Permit: NC0026051
Inspection Date: 09/02/2008
Does the facility analyze process control parameters, for ex: MLSS, MCRT, Settleable Solids. pH, DO Sludge ■
Judge, and other that are applicable?
Record Keeping Yes No NA NE
■ Facility has copy of previous year's Annual Report on file for review?
Comment:
Effluent Pipe Yes No NA NE
■ Is right of way to the outfall properly maintained?
■ Are the receiving water free of foam other than trace amounts and other debris?
If effluent (diffuser pipes are required) are they operating properly?■
Comment:Effluent was clear and very little foam during the time of the inspection.
Bar Screens Yes No NA NE
Type of bar screen
a.Manual
b.Mechanical
Are the bars adequately screening debris?■
Is the screen free of excessive debris?■
Is disposal of screening in compliance?■
Is the unit in good condition?■
Comment:Screenings disposed of in landfill.
Grit Removal Yes No NA NE
Type of grit removal
a.Manual
b. Mechanical
Is the grit free of excessive organic matter?■
Is the grit free of excessive odor'?■
# Is disposal of grit in compliance?■
Comment:Grit held in dumpster and later taken to lanfill.
Nutrient Removal Yes No NA NE
# Is total nitrogen removal required?■
# Is total phosphorous removal required?■
Type Biological
# Is chemical feed required to sustain process?■
Is nutrient removal process operating properly?■
Page #4
Owner - Facility: Triangle WWTP
Inspection Type: Compliance Evaluation
Permit: NC0026051
Inspection Date: 09/02/2008
Permit: NC0026051
Inspection Date: 09/02/2008
Nutrient Removal Yes No NA NE
Secondary Clarifier Yes No NA NE
■ Is the clarifier free of black and odorous wastewater?
Is the site free of excessive buildup of solids in center well of circular clarifier?■
■ Are weirs level?
■ Is the site free of weir blockage?
Is the site free of evidence of short-circuiting?■
■ Is scum removal adequate?
■ Is the site free of excessive floating sludge?
■ Is the drive unit operational?
Is the return rate acceptable (low turbulence)?■
Is the overflow clear of excessive solids/pin floc?■
■ Is the sludge blanket level acceptable? (Approximately X of the sidewall depth)
FiItration (High Rate Tertiary)Yes No NA NE
Type of operation:Down flow
■ Is the filter media present?
■ Is the filter surface free of clogging?
■ Is the filter free of growth?
■Is the air scour operational?
■Is the scouring acceptable?
■ Is the clear well free of excessive solids and filter media?
Comment:
Yes No NA NE
■ Are extra UV bulbs available on site?
■ Are UV bulbs clean?
■ Is UV intensity adequate?
Page #5
Five filters in line. Filters are backwashed every 20 days.
Disinfection - UV
Owner - Facility: Triangle WWTP
Inspection Type: Compliance Evaluation
Comment: Sodium Aluminate is added prior to the Anaerobic selector to aid in the
removal of metals. Methanol is added to aid in denytrification prior to the 1st and 2nd
anoxic zones. Potassium Hydroxide added in the 1 st aerobic zone to adjust pH.
Polymer is added prior to the foru final clarifiers to aid in settling.
Comment: Two clarifiers in use. Clarifiers had a sidewall depth of ten feet and a
sludge blanket of two feet. Weirs are cleaned once a week.
Disinfection - UV Yes No NA NE
■ Is transmittance at or above designed level?
■ Is there a backup system on site?
■ Is effluent clear and free of solids?
Lagoons Yes No NA NE
FacultativeType of lagoons?
# Number of lagoons in operation at time of visit?1
Are lagoons operated in?
■ # Is a re-circulation line present?
■ Is lagoon free of excessive floating materials?
# Are baffles between ponds or effluent baffles adjustable? ■
Are dike slopes clear of woody vegetation?■
■ Are weeds controlled around the edge of the lagoon?
■ Are dikes free of seepage?
Are dikes free of erosion?■
Are dikes free of burrowing animals?■
■ # Has the sludge blanket in the lagoon (s) been measured periodically in multiple locations?
# If excessive algae is present, has barley straw been used to help control the growth?■
Is the lagoon surface free of weeds?■
Is the lagoon free of short circuiting?■
Yes No NA NE
■ Are pumps in place?
Are pumps operational?■
Are there adequate spare parts and supplies on site?■
Comment:
Chemical Feed Yes No NA NE
Is containment adequate?■
Page #6
Owner - Facility: Triangle WWTP
Inspection Type: Compliance Evaluation
Permit: NC0026051
Inspection Date: 09/02/2008
Comment: Bio-Nomics removes thwe sludge. Sludge is taken to Earth Tec to the
company's composting facilitity. No algae control is used to control growth.
Pumps-RAS-WAS
Comment: Two bank system. Had only one system in use. The facility must keep
available bulbs on site.
Chemical Feed Yes No NA NE
■ Is storage adequate?
■ Are backup pumps available?
Is the site free of excessive leaking?
Comment:
Yes No NA NE
# Is composite sampling flow proportional?■
Is sample collected above side streams?■
■ Is proper volume collected?
■ Is the tubing clean'?
■ # Is proper temperature set for sample storage (kept at less than or equal to 6.0 degrees Celsius)?
■ Is sampling performed according to the permit?
Effluent Sampljng Yes No NA NE
■ Is composite sampling flow proportional?
■ Is sample collected below all treatment units?
■ Is proper volume collected?
■ Is the tubing clean?
■ # Is proper temperature set for sample storage (kept at less than or equal to 6.0 degrees Celsius)?
■ Is the facility sampling performed as required by the permit (frequency, sampling type representative)?
Pump Station - influent Yes No NA NE
■ Is the pump wet well free of bypass lines or structures?
■ Is the wet well free of excessive grease?
Are all pumps present?■
■ Are all pumps operable?
■ Are float controls operable?
■ Is SCADA telemetry available and operational?
■ Is audible and visual alarm available and operational?
Page #7
Methanol feed, Potassium Hydroxide, Sodium Aluminate and polymer.
Influent Sampling
Owner - Facility: Triangle WWTP
Inspection Type: Compliance Evaluation
Permit: NC0026051
Inspection Date: 09/02/2008
Comment: All plant operators are certified for field parameters Ph, DO and Ammonia.
Tritest, Enco and Meritec do all analytical work.
Comment: All plant operators are certified for field parameters Ph, DO and Ammonia.
Tritest, Enco and Meritec do all analytical work.
Piu mp Static n - Influ ent Yes No NA NE
Six influent pumps. Visual bulb need to be change during the time of
Upstream / Downstream Sampling Yes No NA NE
Standby Power Yes No NA NE
Is automatically activated standby power available?■
Is the generator tested by interrupting primary power source?■
Is the generator tested under load? ■
Was generator tested & operational during the inspection?■
Do the generator(s) have adequate capacity to operate the entire wastewater site?■
Is there an emergency agreement with a fuel vendor for extended run on back-up power?■
Is the generator fuel level monitored?■
Comment:All standby power generators were tested. Fuel vendor is local.
Laboratory Yes No NA NE
Are field parameters performed by certified personnel or laboratory? ■
Are all other parameters(excluding field parameters) performed by a certified lab? ■ O
# Is the facility using a contract lab? ■
■
■
Incubator (BOD) set to 20.0 degrees Celsius +/-1.0 degrees? ■
Yes No NA NE
Mode of operation
Type of aeration system Diffused
Is the basin free of dead spots?■
Are surface aerators and mixers operational?■
Are the diffusers operational?■
Is the foam the proper color for the treatment process?■
Does the foam cover less than 25% of the basin’s surface?■
Page #8
# Is proper temperature set for sample storage (kept at less than or equal to 6.0 degrees Celsius)?
Incubator (Fecal Coliform) set to 44.5 degrees Celsius*/- 0.2 degrees?
Comment:
inspection.
Permit: NC0026051
Inspection Date: 09/02/2008
Owner - Facility: Triangle WWTP
Inspection Type: Compliance Evaluation
Is the facility sampling performed as required by the permit (frequency, sampling type, and sampling location)? ■
Comment:
Comment: All plant operators are certified for field parameters pH, DO and Ammonia.
Contract labs Tritest, Enco and Meritec do all analytical work.
Aeration Basins
Aeration Basins Yes No NA NE
Is the DO level acceptable? ■
Is the DO level acceptable?(1.0 to 3.0 mg/l) ■
Dissolved Oxygen at the time of inspection was 0.87mg/l. Operator must
Flow Measurement - Influent Yes No NA NE
# Is flow meter used for reporting?■
Is flow meter calibrated annually?■
Is the flow meter operational?■
(If units are separated) Does the chart recorder match the flow meter?■
Influent flow meter is calibrated once a year. Ultrasonic flow transmitter.
Flow Measurement - Effluent Yes No NA NE
# Is flow meter used for reporting?■
Is flow meter calibrated annually?■
Is the flow meter operational?■
(If units are separated) Does the chart recorder match the flow meter?■
Comment:Effluent flow meter calibrated once a year. Tubing changed every week.
Page #9
Comment: I
Tubing changed every week.
Comment: P’
maintain a DO from 1.0 to 3X) mg/l.
Permit: NC0026051
Inspection Date: 09/02/2008
Owner - Facility: Triangle WWTP
Inspection Type: Compliance Evaluation
5
Re:
Dear Mr. Hays:
Sincerely,
Joseph Pearce, Durham County Utility Division Managercc:
A U
.T.waTlTl>p>II
MC062U>5 I
CAdeX
§ \ 4f 4
Mitch Hays,
Environmental Specialist
DWQ Raleigh Regional Office
3800 Barrett Drive
Raleigh. NC 27609
Glenn Vance
Operator in Responsible Charge
5 Day Report-Tertiary Filter By pass
Triangle Wastewater Treatment Plant
WQ0(B£2i—Jlurham County
If you have any questions or need additional information, please contact Glenn Vance at
919-544-8823.
October 16.2003
5# -20080^ [ 9
^Unffed Water
-S^ez
As we discussed by phone today, on October 14, 2008 at approximately 11:30 p.m., an
influent pump station control system malfunction caused a flow surge into the waste
treatment plant. The flow surge was too great for the three tertiary filters on line at the time
to handle. An estimated 100 to 500 gallons of secondary treated water passed over on the
three tertiary filter high flow weirs and into the UV disinfection system. Based upon
interviews with the shift operator the event lasted approximately 15 minutes before the
operator placed additional tertiary filters online, and stopped the bypass event.
To minimize the risk of recurrence, we have 'provided additional operator training
concerning both the operation of the influent pump station and tertiary filters.
Additionally, we are considering regularly operating four of five filters, instead of our
typical three of five filters.
-'j H91TIVH WHOj
I
800Z 0 2 130
United Water Hydro Management LLC
Triangle Wastewater Treatment Plant
5296 NC Highway 55 East
Durham. North Carolina 27713
telephone [phone]
____ facsimile 919 544-8590
T) / c
Michael F. Easley, Governor
October 21,2008
Dear Mr. Pearce,
Cc:
An Equal Opportunity/Affirmative Action Employer - 50% Recycled/10% Post Consumer Paper
North Carolina Division of Water Quality
Internet: ncwaterquality.org
Joe Pearce, Utilities Division Manager
Durham County Engineering Department
102 East Parish Street
Durham, N.C. 27701
Glenn Vance, United Water
Mack Wiggins, RRO
Jerry Rimmer T.A.C.
William G. Ross Jr., Secretary
North Carolina Department of Environment and Natural Resources
Coleen H. Sulims, Director
Division of Water Quality'
Subject: Technical Assistance Evaluation Report
NPDES Number NC0026051
Durham County
NotihCarolina____ Naturally
Customer Service
I-877-623-6748
Sincerely,
Don Register
Wastewater Treatment Plant Consultant
If you have questions concerning this report or if this office can be of additional assistance, please
contact me at 910-433-3309.
A technical assistance request was received and a visit of your facility was conducted on October 1,
2008. I enjoyed meeting with you, Boyd McKenzie, Project Coordinator and Glenn Vance, the facility
ORC. I enjoyed the tour and the discussion regarding your biological nutrient removal system.
Please review the attached report for my comments. The fix is not always straight forward, but take
the suggestions made and continue your conscientious efforts. This office appreciates the
opportunity to meet with you and is available at any time to assist with any compliance issue.
/dujgg
O OCT 2 4 20BL-
IDENR RALEIGH f...
225 Green Street - Suite 714 Fayetteville, NC 28301-5043 Phone [phone]
FAX [phone]
EPA
NPDES
3I 12lNC0026051
21| | I I I I I Illi66I I I I I I I I I I I I I
Entry Time/Date Permit Effective Date
06/11/0101:30 PM 08/10/01
Triangle WWTP
Exit Time/Date Permit Expiration Date5926 NC Hwy 55 E
Durham NC 27701 11/04/3004:00 PM 08/10/01
Other Facility Data
Ralph G Vance/ORC/919-544-8823/
Name. Address of Responsible Official/Title/Phone and Fax Number
Section C: Areas Evaluated During Inspection (Check only those areas evaluated)
Other
Section D: Summary of Finding/Comments (Attach additional sheets of narrative and checklists as necessary)
(See attachment summary)
Name(s) and Signature(s) of Inspector(s)Agency/Office/Phone and Fax Numbers Date
RegisterDon Point Source Compliance Unit//910-433-3300 E
Signatun >f Manai Reviewer Agency/Office/Phone and Fax Numbers:ment
EPA Form 3560-3 (Rev 9-94) Previous editions are obsolete.
Page #1
United States Environmental Protection Agency
Washington, D C. 20460
yr/mo/day
08/10/01
QA
72IJ
Inspection Type
18u
Form Approved.
OMB No. 2040-0057
Approval expires 8-31-98
Name(s) of Onsite Representative(s)/Titles(s)/Phone and Fax Number(s)
///
Facility Self-Monitoring Evaluation Rating
ropj
Date
I11
Section B: Facility Data
Name and Location of Facility Inspected (For Industrial Users discharging to POTW, also include
POTW name and NPDES permit Number)
Fac Type
201 JI17
Inspector
19lll
Inspection Work Days
67| 4.o |69 73| I I74
Remarks
I I I I I I I I I I I I I I I I I I I I I I I
Transaction Code
1 N 2 H
■—Reserved
75l I I I I I I 180
Bl
71U
Marvin Bernard Carter,120 E Parrish St Law Bldg Durham NC 27701/lS9°ntaCted
Back up ORC/919-560-0735/9195600740 L-
Water Compliance Inspection Report
Section A: National Data System Coding (i.e., PCS)
(cont.)1NPDES
I1711
NC0026051
2Page #
yr/mo/day
08/10/01
A contract operations firm (United Water) is operating the WWTP for the owner who is Durham County. The
owners representative (Utility Manager Joe Pearce) requested the technical assistance visit for a third party
opinion of the proper operation of the WWTP. The compliance record for this facility has been outstanding,
(one violation in the past three years). A tour of the facility hosted by Joe Pearce and United Water ORC,
Glenn Vance was very beneficial. The questions asked, replies given, the visual appearance of the
biomass and the effluent gave the appearance of a well operated wastewater facility. Continued
conversation revealed differences of opinion between the contract ORC and the Owner on several
operational strategies. It appeared that one of the main concerns was the over expendature of the chemical
budget line-item. Was the additinal expense due to feeding more chemical or because the cost of the
chemical had increased? The WWTP is a "biological" nutrient removal system with chemical assist and it
may appear that the system is more dependant on the chemicals instead of the biological part of the
process starting up. Although you may be doing all process controls correctly, the process appears to have
a mind of it's own and operates biologically when it chooses. To my knowledge I know of no one that
completely understands this biological process and how it works, so continue to use the chemical addition to
meet compliance. Three things that you may consider is to look at other chemicals that may be more cost
effective than what you are currenly using and secondly I would remove the digester supernant and the filter
backwash from the influent of the plant ASAP. This reduction in loading may help the nutrient removal
biological process restart easier if it is not overloaded. Thirdly are you looking at the VFA(volitle fatty acids)
ratio where the target COD:phosphorus ratio is 40:1? This must be met for the biological process to operate
properly.
12l3I
Inspection Type
18i i
Section D: Summary of Finding/Comments (Attach additional sheets of narrative and checklists as necessary)
t
DENR RALEIGH RECK.
November 21, 2008
Re:
Dear Ms. Garrett:
On the morning of November 21, 2008, an overflow of a sludge dewatering equalization
tank used occurred. This dewatering operation was being performed by Bionomics Inc. as
pail of a sludge removal contract with Durham County. As a result of a mechanical
failure of the tank level indicator, an estimated 500 gallons overflowed onto the ground.
The spill lasted from approximately 6:30 a.m. until 6:45 a.m. A written summary of the
spill event, as provided by Bio-Nomic Services, Inc., is enclosed. After directing initial
clean-up efforts, Joe Pearce and Glenn Vance contacted the Division of Water Quality (at
approximately 8:30 a.m.) concerning the spill and provided initial information to Autumn
Hoban.
To mitigate the spill, the sludge was contained and vacuumed off the ground. Soil below
the spill was excavated to a depth of approximately 2 inches. Lime was applied at this
interface, and topsoil placed where the soil had been removed. Seed and straw were
placed on the topsoil to stabilize the area from erosion. .
RETURN RECEIPT REQUESTED
CERTIFIED MAIL # 7002 0860 0008 6301 3569
120 E. Parrish Street, Law Bldg., 1st Floor, Durham, N.C. 27701 [phone] Fax [phone]
Equal Employment/Affirmative Action Employer
Ms. Judy Garrett
NC DENR
Raleigh Regional Office
1628 Mail Service Center
Raleigh, North Carolina 27699-1628
Triangle Wastewater Treatment Plant Sludge Spill
Durham County
NPDES#NC0026051
BIMS #2000803146
COUNTY OF DURHAM
ENGINEERING DEPARTMENT
roV a
* B
I
w
I
cc:
JRP/ds
Glenn Vance, ORC
Glen Whisler, P.E., County Engineer
Richard Simms, Project Manager
To minimize the risk of recurrence, the failed system is being repaired, a redundant
system is being installed, and secondary containment is being placed around the
equalization tank area. If you have any questions please feel free to contact me at
[phone].
Sincerely,
yoseph Pearce, P.E.
Utility Division Manager
g]002/002
November 22, 2008
Dear Mr. Simms,
Sincerely,
A Carylon Company
Joel L. Coert
Bio-Nomic Services, Inc.
Upon investigating events leading to the incident, it was found that the tank level indicator light
malfunctioned. Therefore, the dredge operator did not realize the tank had over ran prior to disengaging the
pump soon enough.
On November 21, 2008 at approximately 6:30 am some residuals overflowed from the equalization tank
when being filled by the hydraulic dredge. While the majority of the material returned to the lagoon, however
a limited amount migrated away from the lagoon area. The material was immediately contained. As you are
aware the area was then cleaned up the same day as directed without further incident.
This letter is intended to provide a summary of events occurring at the residuals dredging and dewatering
project.
Attn: Richard Simms Fax: [phone]
RE: Residuals Removal Project
Durham County
Engineering Department
120 E. Parrish Street, 1sl Floor
Durham, NC 27701
BIO-NOMIC SERVICES, INC.
Specializing in today's needs for environmental protection.
516 Roundtree Road • Charlotte, North Carolina 28217-2133 • (704)-529-0000 • Fax [phone]
In order to prevent this situation from occurring again, the following measures will be employed. A new
indicator light as well as a back up light system will be installed. Secondary containment will also be placed
around the equalization tank area for additional protection, in case of such an incident, to direct all residuals
back to the lagoon. These measures are scheduled to be put in place on Monday November 24, 2008.
7
, zi/22/2008 SAT 10: 39
/FAX [phone] BIO-NOMIC SERVICES, INC
919-560-0740 COUNTY ENGINEERING
November 21, 2008
Re:
Dear Ms. Garrett:
To mitigate the spill, the sludge was contained and vacuumed off the ground. Soil below
the spill was excavated to a depth of approximately 2 inches. Lime was applied at this
interface, and topsoil placed where the soil had been removed. Seed and straw were
placed on the topsoil to stabilize the area from erosion.
RETURN RECEIPT REQUESTED
CERTIFIED MAIL // 7002 0860 0008 6301 3569
120 E. Parrish Street, Law Bldg., 1st Floor. Durham, N.C. 27701 [phone] Fax [phone]
Equal Employment/Affirmattve Action Employer
Ms. Judy Garrett
NC DENR
Raleigh Regional Office
1628 Mail Service Center
Raleigh, North Carolina 27699-1628
Triangle Wastewater Treatment Plant Sludge Spill
Durham County
NPDES#NC0026051
BIMS #2000803146
COUNTY OF DURHAM
ENGINEERING DEPARTMENT
On the morning of November 21, 2008, an overflow of a sludge dewatering equalization
tank used occurred. This dewatering operation was being performed by Bionomics Inc. as
part of a sludge removal contract with Durham County. As a result of a mechanical
failure of the tank level indicator, an estimated 500 gallons overflowed onto the ground.
The spill lasted from approximately 6:30 a.m. until 6:45 a.m. A written summary of the
spill event, as provided by Bio-Nomic Services, Inc., is enclosed. After directing initial
clean-up efforts, Joe Pearce and Glenn Vance contacted the Division of Water Quality (at
approximately 8:30 a.m.) concerning the spill and provided initial information to Autumn
Hoban.
11/23/2008 13:59 PAGE 02
919-560-0740
Sincerely,
cc:
JRP/ds
Glenn Vance, ORC
Glen Whisler, P.E., County Engineer
Richard Simms. Project Manager
To minimize the risk of recurrence, the failed system is being repaired, a redundant
system is being installed, and secondary containment is being placed around the
equalization tank area. If you have any questions please feel free to contact me at
[phone].
JosOTjh Pearce, P.E.
Utility Division Manager
COUNTY ENGI^^RING PAGE 0311/23/2008 13:59
919-560-0740
' f
November 22,2008
Dear Mr. Simms,
intend6d t0 Pr0Vide a summary of events occurring at the residuals dredging and dewatering
A Carylon Company
Attn: Richard Simms Fax: [phone]
RE: Residuals Removal Project
Durham County
Engineering Department
120 E. Parrish Street, 151 Floor
Durham, NC 27701
BIO-NOMIC SERVICES, INC.
Specializing in today's needs for environmental protection.
516 Roundtree Road • Charlotte, North Carolina 28217-2133 • (704)-529-0000 • Fax [phone]
PAGE 04
waj v * ** • * v
Sincerely,
Joel L. Coett
Bio-Nomic Services, Inc.
—a,„„
^adjnV0 ±C mcident’il was found that tank ^vel indicator light
pump sXrou Jt ’ 86 nOt thC £ank had 0Ver ran prior t0 Engaging the
COUNTY ENGI^^RING11/23/2008 13:59
Michael F. Easley, Governor
November 20, 2008
w 2 A 2008
SUBJECT: Wastewater/Groundwater Laboratory Certification
Dear Mr. Jones:
Sincerely,
cc:
Laboratory Section
Do not hesitate to call on us if we can be of assistance in the future. Contact us immediately at 919-733-3908 if
this action is incorrect or if you have questions.
Per the written request of November 20, 2008, we are discontinuing the certification of your laboratory. We will
proceed with removing your laboratory from the certified list. You are reminded that it is not legal to analyze
environmental samples required by the N.C. Division of Water Quality without our certification.
1623 Mail Service Center; Raleigh, NC 27699-1623
Location: 4405 Reedy Creek Road; Raleigh, NC 27607
Pat Donnelly
Certification Branch Manager
Laboratory Section
William G. Ross Jr., Secretary
North Carolina Department of Environment and Natural Resources
Phone[phone]
FAX [phone]
Coleen II. Sullins, Director
Division of Water Quality
5407
Mr. Jeff Jones
TN & Associates
3100 Smoketree Court, Suite 210
Raleigh, NC 27604
T. Crawford
D. Satterwhite
RRO
Internet: www.dwqlab.orq/Customer Service 1-877-623-6748
An Equal Opportunity/Affirmative Action Employer - 50% Recycled/10% Post Consumer Paper
QE
* X
North CarolinaNaturally
, co i if Ty 9 i / \
11/23/2008 13:58 919-560-0740 COUNTY ENGINEERING PAGE 01
FAX TRANSMITTAL SHEET
November 24, 2008
TO: Judy Garrett
FAX: [phone] FAX: [phone]
Phone:[phone]Phone:
SUBJECT: Triangle Wastewater Treatment Plant Sludge Spill
NOTES/COMMENTS:
■ FOR REVIEW PLEASE COMMENT PLEASE REPLY
Joe Pearce asked me to fax the attached 5-day follow up letter regarding the spill
referenced above to your attention. The original was mailed to you today via
certified mail. If you have any questions, please call 919/560-7992.
120 E. Parrish Street, Law Bldg, First Floor
Durham, NO 27701
PHONE: [phone] FAX: [phone]
COUNTY OF DURHAM
ENGINEERING DEPARTMENT
—
FROM: Deb Stout for Joe Pearce
j URGENT
NUMBER OF PAGES INCLUDING COVER: _4
(If you do not receive all pages, please call 919-560-0735)