NC0003298_AUTHORIZATION TO CONSTRUCT_20031003

NPDES DOCUMENT SCANNING COVER SHEET I
NPDES Permit:
NC0003298
Riegelwood Paper Mill
Document Type:
Permit Issuance
Wasteload Allocation
"
Authorization to Construct -;
(AtQ
Permit Modification
Correspondence
Monitoring Report
Instream Assessment (67B)
Environmental Assessment (EA)
Permit
History
Document Date:
October 3, 2003
Ulm ac oum.eat to rizxtea on reuse a r - ore a:a.
P P Pe i� Y
content ou the reYerse side I

Engineer's 'Certification
I, &re sor)( C. MJ1 S , as a duly registered Pro sional Engineer in the State of
North Carolina, ha*g-tfeen authorized to observe (periodically, eeld full time) the construction of
the project, =hlCrv% i o r #I.. i> uihbuf �U�r1��/ for the
Project Name ll'rC ,yam �o p A7 Location
319-$c
Permittee hereby state that, to the best of my abilities, due care and diligence was used in the
observation of the following installations:
Construction of an earthen berm that will reduce the size of the North Bay settling basin from 50
acres to 32.5 acres
for the above referenced project such that the construction was observed to be built within substantial
compliance and intent of the approved plarliv fid ; s.
CAPO
Signature FF.SS�O��-s� 'registration No. b2 i
e
Date OG.Aaber 3. ZUG3 024935 "
ti
w
r
In addition, please check one of the following:
9 There are still some major components that require completion. Another Engineer's
/'Certificate will be submitted once all substantial construction has been completed.
q/ All substantial construction has been completed.
Mail this Certification to the
NPDES Unit
DENR/DWO
1617 Mail Service Center
Raleigh, NC 27699-1617
W17 t7 0° Iw it

I
o�o� wA
r�Rp�
>_
4 'C
Mr. J. Scott Grimes, Mill Manager
International Paper Company
865 John L. Riegel Road
Riegelwood, North Carolina 28456
Michael F. Easley, Governor
William G. Ross Jr., Secretary
North Carolina Department of Environment and Natural Resources
July 18, 2002
Alan W. Klimek, P.E. Director
Division of Water Quality
Subject: Authorization to Construct
Permit No. NCO003298
ATC No 0003298AC
International Paper Company Riegelwood Mill
Columbus County
Dear Mr. Grimes:
The Division received a letter of request for an Authorization to Construct (ATC) June 20, 2002
and final plans and specifications for this project have been reviewed and found to be satisfactory.
Authorization is hereby granted for the modification of the existing 50 MGD wastewater treatment facility,
which discharges to the Cape Fear River. Specifically, this ATC allows the following:
Construction of an earthen berm that will reduce the size of the North Bay final settling pond, from 50
acres to 32.5 acres to allow expansion of the solid waste landfill. This will reduce the volume of the North
Bay from 156 MG to 128 MG. This will not change any conditions or limitations contained in the permit.
This Authorization to Construct is issued contingent upon the following conditions being met:
-Controls are to be utilized during construction to contain sediment in order to maintain compliance
with effluent limitations
-If the modified wastewater treatment unit does not function in a manner that allows the system to
consistently achieve compliance with effluent limitations, effective actions must be taken to achieve
compliance.
This Authorization to Construct is issued in accordance with Part III, Paragraph A of NPDES
Permit No. NC0003298, and shall be subject to revocation unless the wastewater treatment facilities are
constructed in accordance with the conditions and limitations specified in the permit.
In the event that the facilities fail to perform satisfactorily, including the creation of nuisance
conditions, the Permittee shall take immediate corrective action, including those as may be required by
this Division, such as the construction of additional or replacement wastewater treatment or disposal
facilities.
The Wilmington Regional Office, telephone number [phone], shall be notified at least
forty-eight (48) hours in advance of operation of the installed facilities so that an in -place inspection can
be made. Such notification to the regional supervisor shall be made during the normal office hours from
8:00 a.m. until 5:00 p.m. on Monday through Friday, excluding State Holidays.
N. C. Division of Water Quality 127 Cardinal Drive Extension [phone] Customer Service
Wilmington Regional Office Wilmington, NC 28405 [phone] Fax [phone]

Upon classification of the facility by the Certification Commission, the Permittee shall employ a
certified wastewater treatment plant operator to be in responsible charge (ORC) of the wastewater
treatment facilities. The operator must hold a certificate of the type and grade at least equivalent to or
greater than the classification assigned to the wastewater treatment facilities by the Certification
Commission. The Permittee must also employ a certified back-up operator of the appropriate type and
grade to comply with the conditions of Title 15A, Chapter 8A, .0202. The ORC of the facility must visit
each Class I facility at least weekly and each Class ll, III, and IV facility at least daily, excluding weekends
and holidays, and must properly manage and document daily operation and maintenance of the facility
and must comply with all other conditions of Title 15A, Chapter 8A, .0202. Once the facility is classified,
the Permittee must submit a letter to the Certification Commission, which designates the operator in
responsible charge within thirty days after the wastewater treatment facilities are 50% complete.
A copy of the approved plans and specifications shall be maintained on fife by the Permittee for
the life of the facility.
The Operational Agreement between the Permittee and the Environmental Management
Commission is incorporated herein by reference and is a condition of this Permit. Noncompliance with
the terms of the Operational Agreement shall subject the Permittee to all sanctions provided by G. S. 143-
215.E for violation of or failure to act in accordance with the terms and conditions of this Permit.
Failure to abide by the requirements contained in this Authorization to Construct may subject the
Permittee to an enforcement action by the Division of Water Quality in accordance with North Carolina
General Statute 143-215.6A to 143-215.6C.
The issuance of this Authorization to Construct does not preclude the Permittee from complying
with any and all statutes, rules, regulations, or ordinances which may be imposed by other government
agencies (local, state, and federal) which have jurisdiction.
Upon completion of construction and prior to operation of this permitted facility, a certification
must be received from a professional engineer certifying that the permitted facility has been installed in
accordance with the NPDES Permit, this Authorization to Construct and the approved plans and
specifications. Mail the Certification to the NPDES Unit, P.O. Box 29535, Raleigh, NC 27626-0535.
One (1) set of approved plans and specifications is being forwarded to you. If you have any
questions or need additional information, please contact Mr. Ed Beck, telephone number [phone].
Sincerely,
r
Rick Shiver
Water Quality Regional Supervisor
cc: Central Files
NPDES Permits Unit .
Technical Assistance and Certification Unit
Wilmington Regional Files

INTERNATIONAL PAPER
RIEGELWOOD MILL
JOHN L. RIEGEL ROAD
RIEGELWOOD, NC 284S6
PHONE 91 D-655-221 1
July 12, 2002
Attn: Ed Beck, Environmental Engineer
Division of Water Quality
127 Cardinal Drive Extension
Wilmington, NC 27889
Subject: NPDES Permit No. NCO003298
Authorization to Construct - North Bay Berm
I have enclosed the cross section of the proposed berm that you have requested. This is the main
berm (aligned north 1 south) that will be used to divide the North Bay of the wastewater treatment
system.
If you have questions or need additional information, please call me at [phone].
Sincerely,
Paul T. Sysio
Sr. Environmental Engineer
Encl. Pond Divider Berm drawing
cc: E.J. Kreul, EHS Manager, IP Riegelwood
Greg Richardson, PE "F
G. N. Richardson and Associates
425 North Boylan Avenue
Raleigh, NC 27603
file
JUL Z�O�
1 B-i

INTERNATIONAL PAPERkECEYVFM
t $ RI
EGELWOOD MILL
)OHN L. RIEGEL ROAD
- RIEGELWOOD, NC 28456
PHONE [phone]
June 20, 2002
Attn: Ed Beck, Environmental Engineer
Division of Water Quality
127 Cardinal Drive Extension
Wilmington, NC 27889
Subject: NPDES Permit No. NCO003298
Authorization to Construct - North Bay Berm
I have enclosed an Authorization To Construct (ATC) application for your review. The project
entails a lateral expansion of the existing landfill into a portion of the North Bay. The application
contains a review of the wastewater data as well as the location and volume that will be affected.
If you have questions or need additional information, please call me at [phone].
Sincerely,
Paul T. Syslo
Sr. Environmental Engineer
Encl. Authorization to Construct, CH2MHILL June 18, 2002
cc: E.J. Kreul, EHS Manager, IP Riegelwood
Greg Richardson, PE
G. N. Richardson and Associates
425 North Boylan Avenue
Raleigh, NC 27603
file

CEi2lVIHILL
June 18, 2002
Mr. Paul Syslo
International Paper — Riegelwood Mill
865 John L. Riegel Road
Riegelwood, NC 28456
Subject: Authorization to Construct Application
lnternational Paper Riegelwood Mill
NPDES Permit Number NCO003298
Columbus County
Dear Paul:
CH2M HILL
4824 Parkway Plaza Blvd.
Suite 200
Charlotte, NC
28217.1988
Tel[phone]
Fax 704,329.0141
Proud Sponsor of
National Engineers Week 2000
As requested, CH2M HILL has prepared this Authorization to Construct (ATC) application
for International Paper's (lP) modification of the North Bay final treatment basin at the
Riegelwood, North Carolina, mill. This letter and attachments can be forwarded to DWQ as
IP's request for authorization to construct.
Background
International Paper operates a pulp and paper mill in Riegelwood, NC, which is located on
a tidally influenced section of the Cape Fear River. The mill's wastewater treatment system
includes two primary clarifiers, aerated stabilization basins (ASBs), sludge settling basins,
and a final polishing pond. lP plans to close part of the North Bay to allow expansion of the
mill's landfill.
Solid waste regulations are requiring the closure of the 52 acre unlined landfill at the
Riegelwood mill. In reviewing potential alternate locations, the most feasible location is a
"lateral expansion" of the existing landfill northward into the North Bay of the wastewater
treatment facility. Tk e new landfill will be "piggybacked" onto the existing facility. The
new landfill will be lined as is required by Subtitle D regulations. All leachate from the new
facility will be pumped to the head of the treatment system which currently treats leachate
from the existing landfill. An earthen construction berm will be needed to build the landfill
which will result in a loss of area in the west side of the North Bay. There will not be any
other changes to the North Bay besides the berm. The solid waste permit application for the
landfill expansion was submitted to NC DENR on February 28, 2002, and the permit for the
new landfill is expected in July 2002.

Mr. Paul Syslo
Page 2
June 18, 2002
WWTP Description and Proposed Modifications
The IP wastewater treatment system provides aeration in the front-end of the treatment
system, followed by settling in the back -end. Solids settling is also provided in the South
Bay treatment zone before the wastewater enters the North Bay. The North Bay has a
surface area of approximately 50 acres, with a volume of approximately 156 million gallons.
This corresponds to an average hydraulic retention time of 4.2 days at average mill flows.
The North Bay is not aerated and provides final solids settling before discharge to the Cape
Fear River.
~ Approximately 17.5 acres of the North Bay will be.removed from service to construct the
landfill, which represents a volume of about 28 million gallons. This volume reduction will
change the average retention time of the North Bay settling basin from 4.2 days to 3.5 days.
Attachment 1 presents a review of the historical treatment in the North Bay and the
expected future performance with a reduced volume. The future 3.5 day retention time is
not expected to significantly change the solids removal, and the associated BODs removal, in
the North Bay compared to current performance.
Plans and.Specifications
The berm across the North Bay was designed as part of the landfill expansion project.
Attachment 2 provides the proposed site plan (Drawing S2) and underdrain layout
(Drawing S3) from the landfill design prepared by G.N. Richardson and Associates. The
solid waste permit application package contains the complete site and construction plans
and specifications for the landfill, including the isolation and closure of the western portion
of the North Bay.
The existing treatment system operates under an NPDES permit and will remain in
operation during the landfill construction. The primary treatment zones in the ASB system
(New Bay, Settling Pond, and South Bay) will continue to operate without modifications,
and the North Bay will continue to provide solids settling before discharge. Because the
treatment process is not being changed and no WWTP equipment will be added, the landfill
design drawings are used to show the change in the North Bay area and were used to
determine the future North Bay area and volume.
Design Calculations and Hydraulic Profile
Attachment 1 discusses the change in hydraulic retention time in the basin and the expected
future performance of the North Bay with a reduced volume. Design calculations are not
applicable. The North Bay modifications will not change the WWTP hydraulic profile.
Flow Schematic
Figure 1 presents a block flow diagram for the IP wastewater treatment system.

Mr. Paul Syslo
Page 3
June 18, 2002
Construction Sequence Plan
The mill's wastewater treatment system will continue to operate during the landfill
construction project. A turbidity curtain will be installed across the North Bay to isolate the
berm construction area and the western portion of the North Bay. An equalizing channel
will be constructed on the point of land behind the turbidity curtain to maintain the same
water level of both sides of the curtain during the storage and discharge cycle from the
North Bay. An earthen berm will then be constructed on the west side of the turbidity
curtain -to define the landfill expansion footprint. After the berm is completed, water from
the isolated,•western portion of -the North Bay (landfill footprint) will be pumped -the
headworks of the wastewater treatment system. -Water from construction dewatering
activities and the future landfill underdrain system also will be pumped to the headworks.
North Bay effluent solids will be monitored during the construction activities to maintain
permit compliance. Construction activities will be stopped or methods changed if the berm
construction causes the effluent solids levels to approach the permit limits.
Sincerely,
uu+rii,,.
M,q k,'�.
CH2M HILL
ASS
RFo
L d
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Na. t7666
PROFESSIONAL
Hal A. Davis, P.E.
Project Manager
;
'.,y.� �NGINEE� ��.�•'�
,�,lq• DA�1S`1���
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Attachments NC Temporary Permit No. T-2563
Expiration Date of Permit: Aug 30, 2002
cc: Bill Kreutzberger/CH2M HILL Date of Signing:

e
Mill Wastewater Outf all to
10 Cape Fear River'
Solids to
dewatering
New Bay Settling Pond South Bay North Bay
Primary Clarifiers Aeration Basin (4.5 acres, 29 MG) Aeration & Settling Settling Basin
(43.5 acres, 283 MG) (51.8 acres, 338 MG) (32 acres, 128 MG)
(1 @ 200 It diam, ;
1 @ 320 it diam)
Figure 1
WWTP Flow Diagram
IP Riegelwood
u

Attachment 1
North Bay Treatment Evaluation

TECHNIC'KL-'-MEM0AANDUM - CH2MHiLL
North Bay Treatment Evaluation
PREPARED FOR: International Paper - Riegelwood Mill
PREPARED BY: Hal Davis/CH2M HILL
DATE: June 1, 2002
International Paper (IP) operates a pulp and paper mill in Riegelwood, NC, which is located
on a tidally influenced section of the Cape Fear River. The mill's wastewater treatment
system includes two primary clarifiers, aerated stabilization basins (ASBs), sludge settling
basins, 'and a final polishing pond (North Bay): IP plans to close part of the North Bay to
allow expansion of the izii1l's-landfill, arid regiie§feel assistdnce'witli a review of existing
North Bay data to assess potential treatment impacts associated with a reduced volume in
the North Bay. This memorandum describes the North Bay, and discusses historical
treatment in the North Bay and expected future performance with a reduced volume.
Background
The IP wastewater treatment system provides aeration in the front-end of the treatment
system, followed by settling in the back -end. Solids settling is also provided in the South
Bay treatment zone before the wastewater enters the North Bay. Figure 1 presents a site
plan of the mill's wastewater treatment system. The North Bay has a surface area of
approximately 50 acres, with a volume of approximately 156 million gallons. This
corresponds to an average hydraulic retention time of 4.2 days at average mill flows. The
mill discharges to the Cape Fear River with the falling tide, and the North Bay provides
effluent storage between the tidal discharge periods. IP staff indicated that the North Bay
water level varies by approximately 8 inches during the storage and discharge cycle.
The North Bay is not aerated and provides final polishing for solids settling before
discharge to the Cape Fear River. The majority of the solids settling occurs in the South Bay.
The North Bay is an irregular shaped impoundment, with several isolated cove areas in the
western third of the pond. The North Bay inlet is located near the south corner of the pond,
and the discharge pipe is located on the north side of the pond, about 1800 feet directly
across from the inlet. Based on the basin geometry, the western portion of the North Bay
appears to be outside the primary flow path through the basin. The normal flow path is a
relatively straight route from the pond inlet to the pond outlet. The flow must make a 90
degree turn to enter the western portion of the North Bay, which is also moving away from
the pond outlet. A curtain wall was installed in the North Bay in late 1998 to provide a
barrier for sediments in site runoff entering from the landfill and areas along the western
side of the North Bay. The curtain is approximately 400 feet long, and extends from the
north bank across about 80 percent of the entrance to the west portion of the North Bay. The
curtain partitions off about 17 acres in the western end of the North Bay. Because the
western section of the North Bay is isolated from the main flow path through the pond,
most solids settling occurs in the eastern two tlurds of the North Bay.
CLTAP NORTH BAY TM_R2,DOC 1 158825.TA.01

NORTH BAY TREATMENT EVALUATION
IP proposes a lateral expansion of the existing landfill by taking a portion of the North Bay
polishing pond out of service. Approximately 17.5 acres of the North Bay will be removed
from service, which represents a volume of about 28 million gallons.
Data Review
Daily data for the North Bay inlet (South Bay effluent) and North Bay effluent from January
1998 to January 2002 were reviewed to assess BOD and TSS removal across the polishing
basin. Table 1 presents the averages of the inlet and effluent data for the entire 4 year
period, individual years, and the period of January 1999 to January 2002.
TABLE 1
Annual Average North Bay Inlet and Effluent
Period
FIDw
(mgd)
GODS
(mglL)
North Bay Inlet
SODS TSS
(Ibld) (mglL)
TSS
(Ibld)
BODs
(mglL)
North Bay Effluent
BOD5 TSS
(Ib/d) (mglL)
TSS
(Ibld)
Removal
BODr TSSr
(lb/d) (Ibld)
Average
36.9
22
6804
34
10300
16
5040
19
5833
1944
5185
1998
36.9
27
8310
54
15380
20
6072
26
7674
2594
7252
1999
37.9
22
7089
36
11529
17
5475
19
5932
1805
8957
2000
36.8
21
6541
32
9699
16
4795
19
5853
1855
3940
2001
36.2
18
5377
25
7522
13
3895
13
3817
1576
4240
1199-
36.9
20
6320
29
8863
15
4706
17
5183
1743
4582
1102
For the 4 year period reviewed, the average effluent flow rate was 36.9 mgd, and varied
little from year to year. The North Bay inlet BOD5 and TSS mass loads were highest in 1998
and decreased each year through 2001. The North Bay effluent BOD5 and TSS mass loads
also were highest in 1998 and decreased each year through 2001. The BOD5 removal across
the North Bay averaged 26 percent for the entire period, and annual BOD5 removal rates
ranged from 23 percent in 1999 to 29 percent in 2001. On a mass basis, the BODS and TSS
removal across the North Bay was highest in 1998. The BOD5 and TSS mass removal was
lower in 1999-2001, which corresponds to the lower BOD5 and TSS loads entering the North
Bay during these years.
BODS removal in the North Bay is primarily associated with solids settling in the unaerated
basin. Figures 2 and 3 present plots of BOD5 vs. TSS concentration for the North Bay inlet
and North Bay effluent, respectively. The data plot as a band with the Y intercept providing
an estimate of the soluble BOD5 concentration. Based on these plots, the estimated soluble
BOD5 for the North Bay inlet and effluent is similar at 6 to 7 mg/L. The similar inlet and
effluent soluble BOD5 concentrations indicate that little soluble BOD5 removal occurs in the
North Bay, and suggests that the total BOD5; reduction measured across the North Bay is
associated with solids settling. The majority of the biological solids settle in the South Bay
with further TSS reduction across the North Bay (typically a 10 to 20 mg/L reduction).
CLT4P NORTH BAY TM_R2,OOC

NORTH BAY TREATMENT EVALUATION
w
Future North Bay -Operations
The North Bay operating conditions before and after the landfill expansion are presented in
Table 2.
TABLE 2
Norlh Bay Operating Cases
Case Area (acres) Volume (MG) HRT (days),
Existing North Bay 50 156 4.2
Future North Bay 32.5 128 3.5
1. Calculated retention time at average flow of 36.9 mgd
,j
-Closing the western third of.the.North-Bay will.reduce the.theoretical retention -time _to _._. _
approximately 3.5 days in the final settling pond. However, given the geometry of the
North Bay and the fact that the western portion is already isolated by the curtain, little
impact on the TSS removal efficiency is anticipated with the removal of 17.5 acres in the
west side of the North Bay.
Because the BOD5 reduction in the North Bay appears to be related to solids removal, future
effluent BODs concentrations are also expected to be similar to current levels provided that
current solids removal performance is maintained. The projected retention time after the
modification is sufficient to maintain the level of TSS removal currently obtained in the
North Bay based on experience with ASB systems at other pulp and paper mills. The North
Bay water level will vary by approximately 12 inches during the storage and discharge cycle
in the future compared to the current 8 inch level change. Mill staff indicate that the pond
has the ability to handle the future variability in the North Bay water level.
Conclusions
Based on a review of North Bay data for 1998 to 2001 and the configuration of the North
Bay, the following conclusions are provided:
• The North Bay provides final polishing treatment for solids settling before discharge to
i
the Cape Fear River.
• The western portion of the North Bay is isolated from the main body of the North Bay
by the pond's geometry and a curtain wall extending across a narrow section of the
pond. The western portion of the North Bay is also outside the normal flog path of
influent from the South Bay.
i
• The majority of the settleable suspended solids entering the North Bay are expected to
removed with a retention time of one day or more. Suspended solids removal in the
North Bay is not expected to change significantly with the future 3.5 day retention time.
• BODS reduction in the North Bay is associated with solids removal. Future effluent
BODS concentrations are expected to remain similar to current levels provided that
'
current solids removal performance is maintained.
CLTAP NORTH BAY TM_R2.DOC 3

SPILLWAY
ELECTRICAL CONTROL STATIONS
❑ 5011P AERATORS x 9 R 450 TOTAL HP
0 20W AERATORS x 7 w 140
31 �� ® 75HP AERATORS x 80 s 6000 _
6590 SU1310TAL F1P
Bay
32 aT acres RECIRCULATION PUMPS 60.5 MCD x 4 = 242 MCD
32 a,w
(428 MG) -- •,y
OrL �- 42 ACRES
PLANT NORT Qe40 �eitr � �9P1 .
yea i a.� 0...
SANITARY. LANDFILL50 ACRES ir 0.
yl=' •u w / E ;
Landf[H Expansion DEWATERED • 7
SLUDGE STORAGE �• ` •,r r
Of
SLUDCE PONOs ;
35 ACRES
(Y LIME MUD 'i• �.� rj A
POND �• 1 '
Q f213
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pw
0� LEGEND '
p f INTERNATIONAL PAPER
>y RIEGELWOOD MILL
DRAWN. JDC
r CHECKED JLz FIGURE z
APPROVED JLZ WASTEWA i'ER TREATMENT
S()ALt 1- Q 600'--0• REV 09OCT91 11„ 2CAUC96 SYSTEM
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BO
0
(m
gA) 60
40
20
0
120
100
8o
BD
0
(m
gn) 60
40
20
0
0
NORTH BAY TREATMENT EVALUATION
Figure 2: South Bay Effluent BOD vs TSS
_i
y e 0.4306x . 5.7957
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i
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:.�•�.f f�• • f• +� f•f ifI f�i•f • s ••
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f
I i
20 40 60 60
TSS (mgA)
Figure 3: North Bay Effluent BOD vs TSS
0 20 40 60
T85 (mgI11
100 120
60 100 120
CLTAP NORTH BAY TM- R2.DOC 4

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PERMIT APPLICATI

INTERNATIONALO PAPER
RIEGELWOOD MILL
JOHN L. RIEGEL ROAD
RIEGELWOOD, NC 28456
PHONE [phone]
April 22, 2002
Certified Mail
Attn: Ed Beek
Division of Water Quality
127 Cardinal Drive Extension
Wilmington, NC 28405
Subject: NPDES Permit No. NCO003298
Lateral Expansion of Landfill
I have enclosed CH2MHill's assessment of the North Bay landfill project on the mill wastewater
treatment system. The report reviews the historical performance of the system and predicts the effects
of removing approximately 17 acres from the North Bay.
If you have questions or need additional information, please call me at [phone]
Sincerely,
Paul T. Syslo
Sr. Environmental Engineer
Encl. CI-12MHill Proposal
cc: J.D. Dew — IP Riegelwood
E.J. Kreul —IP Riegelwood
MAY - 9 2002
D£NR - WATER QUALITY
POINT SOURCE BRANCH

TECHNICAL MEMORANDUM CH2MHILL
North Bay Treatment Evaluation
PREPARED FOR: International Paper - Riegelwood Mill
PREPARED BY: Hal Davis/CH2M HILL
DATE: April 15, 2002
International Paper (IP) operates a pulp and paper mill in Riegelwood, NC, which is located
on a tidally influenced section of the Cape Fear River. The mill's wastewater treatment
system includes two primary clarifiers, aerated stabilization basins (ASBs), sludge settling
basins, and a final polishing pond (North Bay). IP plans to close part of the North Bay to
allow expansion of the mill's landfill, and requested assistance with a review of existing
North Bay data to assess potential treatment impacts associated with a reduced volume in
the North Bay. This memorandum describes the North Bay, and discusses historical
treatment in the North Bay and expected future performance with a reduced volume.
Background
The IP wastewater treatment system provides aeration in the front-end of the treatment
system, followed by settling in the back -end. Solids settling is also provided in the South
Bay treatment zone before the wastewater enters the North Bay. Figure 1 presents a site
plan of the mill's wastewater treatment system. The North Bay has a surface area of
approximately 50 acres, with a volume of approximately 156 million gallons. This
corresponds to an average hydraulic retention time of 4.2 days at average mill flows. The
mill discharges to the Cape Fear River with the falling tide, and the North Bay provides
effluent storage between the tidal discharge periods. IP staff indicated that the North Bay
water level varies by approximately 8 inches during the storage and discharge cycle.
The North Bay is not aerated and provides final polishing for solids settling before
discharge to the Cape Fear River. The majority of the solids settling occurs in the South Bay.
The North Bay is an irregular shaped impoundment, with several isolated cove areas in the
western third of the pond. The North Bay inlet is located near the south comer of the pond,
and the discharge pipe is located on the north side of the pond, about 1800 feet directly
across from the inlet. Based on the basingeometry, the western portion of .the North Bay
appears to be outside the primary flow path through the basin. The normal flow path is a
relatively straight route from the pond inlet to the pond outlet. The flow must make a 90
degree turn to enter the western portion of the North Bay, which is also, movingaway from
the pond outlet..A curtain wall was installed in the North Bay in late 1998 to provide a
barrier for sediments in site runoff entering from the landfill and areas along the western
side of the North Bay. The curtain is approximately 400 feet Iong, and extends from the
north bank across about 80 percent of the entrance to the west portion of the North Bay. The
curtain partitions off about 17 acres in the western end of the North Bay. Because the
western section of the North Bay is isolated from the main flow path through the pond,
most solids settling occurs in the eastern two thirds of the North Bay.
CLDIP NORTH BAY TM_R2.DOC 1 158825.TA.01

NORTH DAY TREATMENT EVALUATION
IP proposes a lateral expansion of the existing landfill by taking a portion of the North Bay
polishing pond out of service. Approximately 17.5 acres of the North Bay will be removed
from service, which represents a volume of about 28 million gallons.
Data Review
Daily data for the North Bay inlet (South Bay effluent) and North Bay effluent from January
1998 to January 2002 were reviewed to assess BOD and TSS removal across the polishing
basin. Table 1 presents the averages of the inlet and effluent data for the entire 4 year
period, individual years, and the period of January 1999 to January 2002.
TABLE 1
Annual Average North Bay Inlet and Effluent
Period
Flow
(mgd)
BODE
(mg1L)
North Bay Inlet
BODs TSS
(Ibld) (mg1L)
TSS
(Ibld)
BODE
(mg/L)
North Bay Effluent
BODE TSS
(Ibld) (mg/L)
TSS
(lbld)
Removal
BODr TSSr
(lbld) (lbld)
Average
36.9
22
6804
34
10300
16
5040
19
5833
1944
5185
1998
36.9
27
8310
54
15380
20
6072
26
7674
2594
7252
1999
37.9
22
7089
36
11529
17
5475
19
5932
1805
8957
2000
36.8
21
6541
32
9699
16
4795
19
5853
1855
3940
2001
36.2
18
5377
25
7522
13
3895
13
3817
1576
4240
1/99-
36.9
20
6320
29
8863
15
4706
17
5183
1743
4582
1 /02
For the 4 year period reviewed, the average effluent flow rate was 36.9 mgd, and varied
little from year to year. The North Bay inlet BOD5 and TSS mass loads were highest in 1998
and decreased each year through 2001. The North Bay effluent BOD5 and TSS mass loads
also were highest in 1998 and decreased each year through 2001. The BOD5 removal across
the North Bay averaged 26 percent for the entire period, and annual BOD5 removal rates
ranged from 23 percent in 1999 to 29 percent in 2001. On a mass basis, the .BOD5 and TSS
removal across the North Bay was highest in 1998. The BOD5 and TSS mass.removal was
lower -in 1999-2001, which corresponds to the'lower BOD5 and TSS loads entering the North
Bay during these years.
BODs removal in .the North Bay is primarily associated with solids settling in the unaerated
basin. Figures 2 and 3 present plots of BOD5 vs. TSS concentration for the.North Bay inlet
and North Bay effluent, respectively. The data plot as a band with the Y intercept providing
an estimate of the soluble BOD5 concentration. Based on these plots, the estimated soluble
BOD5 for the North Bay inlet and effluent is similar at 6 to 7 mg/ L. The similar inlet and
effluent soluble BOD5 concentrations indicate that little soluble BODS removal occurs in the
North Bay, and suggests that the total BOD5 reduction measured across the North Bay is
associated with solids settling. The majority of the biological solids settle in the South Bay
with further TSS reduction across the North Bay (typically a 10 to 20 mg/ L reduction).
CLTAP NORTH aAY TM-R2.000

NORTH BAY TREATMENT EVALUATION
Future North Bay Operations
The North Bay operating conditions before and after the landfill expansion are presented in
Table 2.
TABLE 2
North Bay Operating Cases
Case Area (acres) Volume (MG) HRT (days),
Existing North Bay 50 156 4.2
Future North Bay 32.5 128 3.5
1. Calculated retention time at average flow of 36.9 mgd
Closing the western third of the North Bay will reduce the theoretical retention time to
approximately 3.5 days in the final settling pond. However, given the geometry of the
North Bay and the fact that the western portion is already isolated by the curtain, little
impact on the TSS removal efficiency is anticipated with the removal of 17.5 acres in the
west side of the North Bay.
Because the BODs reduction in the North Bay appears to be related to solids removal, future
effluent BODs concentrations are also expected to be similar to current levels provided that
current solids removal performance is maintained. The projected retention time after the
modification is sufficient to maintain the level of TSS removal currently obtained in the
North Bay based on experience with ASB systems at other pulp and paper mills. The North
Bay water level will vary by approximately 12 inches during the storage and discharge cycle
in the future compared to the current 8 inch level change. Mill staff indicate that the pond
has the ability to handle the future variability in the North Bay water level.
Conclusions
Based on a review of North Bay data for 1998 to 2001 and the configuration of the North
Bay, the following conclusions are provided:
The North Bay provides final polishing treatment for solids settling before discharge to
the Cape Fear River.
• The western portion of the.North Bay is isolated from the main body of the North Bay
by the pond's geometry and a curtain wall extending across a narrow section of the
pond. The western portion of the North Bay is also outside the normal flow path of
influent from the South Bay.
• The majority of the settleable suspended solids entering the North Bay are expected to
removed with a retention time of one day or more. Suspended solids removal in the
North Bay is not expected to change significantly with the future 3.5 day retention time.
• BOD,s reduction in the North Bay is associated with solids removal. Future effluent
BOD5 concentrations are expected to remain similar to current levels provided that
current solids removal performance is maintained.
CLTAP NORTH BAY TM_R2.000

' f
NORTH BAY TREATMENT EVALUATION
120
100
80
BO
D
(m
911) 60
40
20
a
120
100
80
Bo
D
lm
gA) 60
40
20
0
Figure 2: South Bay Effluent BOD vs TSS
I I i
y r 0.4308x a 5,7957
I
i f
I
I
! '
I E I
" I
N a� •
i
0
20 40 60 80
TSS ImgM
Figure 3: North Bay Effluent BOD vs TSS
I !
• , • • ••
I
0 20 40 60
TSS (mgA)
100 120
80 100 120
CLTAP NORTH BAY TM_R2.DOC 4

K
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50 acres
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LEGEND
SPILLWAY
ELECTRICAL CONTROL STATIONS
50HP AERATORS x 9 — 450 TOTAL HP
0 2011P AERATORS x 7 - .140
® 75HP AERATORS x 80 a 6000
6590 SUBIOTAL W
RECIRCULATION PUMPS 60.5 MOD x 4 = 242 MGO
42 ACRES
eti.l T W. 0 42uC0
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