NC0023965_Instream Assessment_19881228

NPDES DOCUNENT'SCAMMIMO COVER SHEET
NPDES Permit:
NCO023965
Wilmington - Northside WWTP
Document Type:
Permit Issuance
Wasteload Allocation
Authorization to Construct (AtC)
Permit Modification
Engineering Alternatives Analysis
201 Facilities Plan
Instream Assessment (67B)
Staff Report
Permit History
Date Range:
Document Date:
December 28, 1988
THIS DOCUMENT IS PRINTED ON REUSE PAPER - IGNORE ANY CONTENT ON THE
REVERSE SIDE

Request Form for In -stream Assessment for 67B
NAME OF FACILITY W) �nni�L�. _-14 Z115iDs_-_ SUBBASIN-®3'o�' /�-
COUNTY REGION DESIGN --- DESIGN FLOW
RECEIVING STREAM
BACKGROUND DATA :
A. Why is SOC needed? (Facility is out of compliance with which
effluent limits?)
B. History of SOC requests:
1. Monthly Average waste flow. /
prior to any SOC 36(iG mgd
Time period averaged /14 ket thru ,but
2. Previously approved SOC's:
Date: flow: Q mgd
Date: flow: mgd
total of previously approved SOC flow: (Q mgd
3. Flows lost from plant
(facilities that have gone
off line)
4. Current SOC request
5. Total plant flow post-SOC
(sum of original flow and
SOC flow minus losses)
flow: C2 mgd
flow: "ae -mgd
flow: g, -4 d-" mgd
-- 6. Is this an accurate flow balance for plant? Why/why not?

C. Please attach DMR summary for past year for all permitted parame-
ters. If possible, include reports from previous years if
facility has been under SOC for more than a year.
CURRENT-SOC-REQUEST :
A. Request is for domestic or industrial waste? If it is a combin-
ation, please specify percentages.
C�Omesi-C. W434t�JA7"%­-.
B. What type of industry? Please attach any pertinent data.
C. The region proposes the following SOC limits:
B OD 5 J� D mg/ 1 ��4Pa%C SetP� a/�I
DO— mg/1
TSS— mg/1
fecal coliform #/100ml
PH SU
other parameters
D. what is the basis for these limits?
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CITY of WILM NGTON
_ North Caro i na
1739
P.O. BOX 1810
28402
Mr. Paul Wilms
Director of Environmental Management
P. 0. Box 27687
Raleigh, NC 27611
Dear Mr. Wilms:
PUBLIC UTILITIES DEPARTMENT
November 22. 1998
AOV 28 1988
I�88 DIV;OFENVIROMWATALALAMAGE H
RNaiBh, MC
The purpose of this letter is to request a Special Order `by
Consent to be issued by you, pursuant to G.S. 143-215.673. The
City of Wilmington desires to enter into an Administrative
Special Order By Consent for the Northside "James A. Loughlin"
Wastewater Treatment Plant. Under this consent agreement, new
additional wastewater flows to this plant would be limited.
Since December 1995 until and including October 1988, the
Northside Plant has been experiencing difficulties in meeting its
monthly average 30 mg/1 BODS limits. From December 1985 until
October 19g8, a 35 month period, the plant had exceeded its
limits in 13 months (37% of the months)and has been at 28 mg/l
BODS or above in 9 months (26V. of the months). In addition, the
City of Wilmington has spent a total of.%623,588.78 on chemical
costs alone which have been used to reduce BOD and suspended
solids in order to assist the Northside Plant in meetinq
compliance for the period beginning March 1986 thru September l4,
1908.
A study conducted by the firm of Black & Veatch, Inc., and
entitled "Northside Wastewater Plant Non -Compliance Study" dated
October 1986 determined that the existing trickling filters could
not provide effective treatment for 8 MGD (hydraulic desiqn flow)
and further that the Plant was currently on the border line of
meeting its monthly BODS limits during specific periods of the
year under certain BOD influent loading conditions. Further, the
City authorized and has completed under contract with the firm of
Black & Veatch, Inc. a study entitled "James A. Loughlin
Wastewater Treatment Plant Upgrade/Expansion Evaluation" dated
July 1988. This report examined various alternatives for

Mr. Paul Wilms
November 22, 19ee
Page 2
upgrading and/or expanding of the plant. Subsequent to this
study, the City entered into a design contract with Black &
Veatch, Inc. on September 26, 19BB in order to upgrade the plant
so,that it will be able to effectively treat 8 MGD at an influent
strength of 200 mg/l BOD and 150 mg/1 total suspended solids.
The total cost of the design contract with Black & Veatch is
approximately $588,000. The total estimated cost of the upgrade
of the Northside Wastewater Treatment Plant is approximately
$3,000,000.
Since the City of Wilmington faces the prospect of totally
funding the upgrade of the Northside Wastewater Treatment Plant
with the use of local funds, it is necessary for the City to
reduce as much as possible our existing and future operating
costs. At the current rates chemical feed is being used to
reduce BOD loadings, it is projected that expenditures could
approximate $937,500 over the next 2-1/2 years in chemical feed
costs alone. This budget estimate is based on using chemical
feed for 10 months during a 12 month fiscal year. These costs
' could be higher if more chemicals are used during each 12 month
period, or if the price of chemicals increases. Also, the
additional costs for wastewater sludge generated (as a result of
chemical feed) has also increased operational costs.
The completion date for the construction of the Northside
Wastewater Treatment Plant is scheduled for March 31. 1991. As I
have stated, the City has made a sincere commitment for meeting
this target date by entering into the design contract with Black
& Veatch. Inc. The City continues to try to meet,its effluent
limits through the use of chemical feed. However, the use of
chemicals has proven to be a "hit" and "miss" proposition as
indicated by the fact that 63% of the months (from 12/85 - 10/88)
the plant was at 28 mg/1 BODS or greater.
I fully recognize that you need not necessarily be concerned
with the cost of treatment which any entity may need to absorb.
Nonetheless, if we were granted your permission to have revised,
temporary limits, which we could operationally meet, and if we
were permitted to decrease the use of chemical feed, then the
financing of the improvements to the Northside Wastewater
Treatment Plant would be less burdensome on our customers.

Mr.. Paul Wilms
November 22, 1908
Page 3
The City of Wilmington respectfully requests monthly limits
of: 1.) for the period April, May, June, July, August and
Sep,tember - 40 mg/1 BOD5: 2.) for the months of October,
November, December, January, February, and March - 45 mg/l BOD5.
These limits would be in effect during the time frame
specified under the SOC issuedpursuant to your authority.
Further, the City of Wilmington agrees to limit additional
wastewater flows under the time frame of the Special Order to no
more than a total of 400,000 gpd contributed during this time
frame up until March 31, 1991.
I am enclosing for your review and consideration a
resolution passed by the Wilmington City Council which agrees to
the stipulations contained in this letter. Also enclosed is a
copy of the design contract with Black & Veatch, a copy of their
most recent report to us, as well as a copy of the Northside
Upgrade/Expansion report which was completed in July 1988. 1
respectfully await your favorable decision in this regard.
Respectfully submitted,
�L, 6�
John Bauer
Director of Public Utilities
JB:bm
howardem
Enclosures
cc: Mr. Preston Howard
Mr. William B. Farris
Mr. W. T. Anderson
Mr. Pete Shelly

b}^ William B. Farris, City Manager
�8 v1.y wuil�ll
City of Wilmington
North Camlina
November 22 �Q gg
RESOLUTION REQUESTING THE
DIRECTOR OF THE ENVIRONMENTAL
MANAGEMENT COMMISSION TO GRANT
THE CITY OF WILMINGTON A SPECIAL
ORDER BY CONSENT FOR THE
NORTHSIDE WASTEWATER TREATMENT PLANT
WHEREAS, the James A. Loughlin Wastewater Treatment Plant
(the "Northside Plant") has been in violation of its NPDES Permit
No. NC0023965 for thirteen (13) months during a thirty-five (35)
month reporting period (December 1985 thru October, 1988) with
respect to exceeding the monthly average permit limit of 30 mg/1
for effluent BODS; and
WHEREAS, under G.S. 143-215.67B, the Director of the
Environmental Management Commission has the authority to grant
the City of Wilmington a Special Order by Consent;
WHEREAS, the Mayor and Members of City Council agree to
abide by the stipulations contained in the requested Special
Order by Consent;
WHEREAS, the City has entered into a contract with Black &
Veatch, Inc. on September 26, 1988 in the total amount of
$5B8,000 in order to design the upgrade of the Northside Plant so
that it can meet its monthly average permit limit of 30 mg/1 for
effluent BODS at an influent strength of 200 mg/1 HOD and 150
mg/1 total suspended solids at average flows of 8 MGD.
NOW, THEREFORE, BE IT
RESOLVED, that the City of Wilmington hereby requests the
Director of the Environmental Management Commission to grant a
Special Order by Consent and the City of Wilmington agrees to
enter into and abide by this Special Order by Consent as
stipulated as follows:
1. That the Special Order by Consent shall expire on March
31, 1991;
2. That until the expiration of the Special Order by
Consent, the permitted GODS effluent limitations of the
Northside Plant shall be 45 mg/1 as a monthly average
for the months of October, November, December, January,
- February, andMarchand 40 mg/l as a monthly average
forthe months of April, May, June, July, August, and
September;

3. That the City holds North Carolina NPDES Permit No.
NC0O23965 for operation of an existing wastewater
treatment works (the Northside Plant) and making an
outlet therefrom for treated wastewater to the Cape
Fear River, but is unable to comply with the effluent
limitati.ons for BODS, as set forth in the City's 201
plan to protect water quality standards. Compliance
will require preparation of plans and specifications
for and construction and operation of additional
treatment works;
4. That non-compliance with final effluent limitations
constitutes causing and contributing to pollution of
the waters of this State named above, and the City is
within the ,jurisdiction of the Environmental Management
Commission as set forth in Chapter 143, Article 21 of
the North Carolina General Statutes;
5. That the City desires to cause or allow the discharge
of 400,000 gpd of additional wastewater to the
treatment works, and that the discharge of such
additional wastewater from the treatment works of the
waters of this State will not result in any significant
degradation in their quality or in the quality of any
water ultimately receiving such discharge;
6. That the City has secur.ed financing for planning '.or
treatment works which, when constructed and operated,
will be sufficient to adequately treat the wastewater
presently being discharged and the additional
wastewater desired to be discharged, to the extent that
the City will be able to comply with final permit
effluent limitations;
7. That John Bauer, Director of Public Utilities, and
successors so titled shall be authorized to act on and
behalf of the City of Wilmington in all matters related
to this Special Order of Consent;
B. Any violation of terms of the Special Order of Consent
subjects the City to enforcement authority of the
Commission and the Director.
Mayor
Adopted at a regular meeting
on November 22 198 8 .
ATTEST:
L.�
City Clerk
CERTIFIED TO BE A TRUE COPY

?Z,IW.S D 144 i'
A?P2oVA L — (00 D4 S Is'
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Black & Veatch UC,US %
CoV57 - 8 �_40"7-NS
PRELIMINARY BASIS OF DESIGN MEMORANDUM
Wilmington, North Carolina
Northside WWTP Upgrade
To: Distribution
From: P.C.R. Shelley, Project Manager
F.R. Stroud, Project Engineer
i
GENERAL
B&V Project 03408.100
B&V File
October 19, 1988
Revised 12/5/88
This project includes the preparation of drawings and specifications for
upgrading the City of Wilmington's James A. Loughlin (Northside) Wastewater
Treatment Plant to 8 mgd. The upgrade will be constructed at the existing
facilities.
BACKGROUND INFORMATION
The upgrade is based on the report "James A. Loughlin WWTP
Upgrade/Expansion Evaluation" dated July 1988 and prepared by Black & Veatch,
Inc. This study was conducted after Ae report "Northside Wastewater
Treatment Plant Non -Compliance Study" dated October 1986 and prepared by
Black & Veatch, Inc. determined the existing trickling filters could not
provide the necessary treatment for 8 mgd.
The recommendation of this report was to upgrade the plant with the
addition of an aeration basin to provide short term aeration and which can be
expanded to a 20 mgd complete mix activated sludge treatment facility. When
the plant is expanded, the trickling filters will be abandoned and the
facility will be an activated sludge plant that must be capable of treating
greater influent loadings and provide nitrification and biological phosphorus
removal.
CONTRACTS
Due to the North Carolina State Law, the project will be divided into
two sections to be bid separately as follows:
DATUM
Section 1 - General
Section 2 - Electrical
USGS datum
DRAFTING STANDARDS AND PROCEDURES
Use B&V drafting standards on 24x36 mylar
FF6 2 o
TF�HN/,-"C Sf,4/,Ic fs '9�9
ak�N�f,

Black & Veatch
PRELIMINARY BASIS OF DESIGN MEMORANDUM
Wilmington, North Carolina 2
Northside WWTP Upgrade
SOIL BORING
B&V Project 03408.100
October 19, 1988
Borings will be performed by Soils & Materials Engineering.
SURVEYS
A topographic survey of the project site will be performed. All invert,
weir, water level, etc. elevations for the existing facilities will be
verified. The survey will be performed by McKim & Creed Consulting
Engineers.
SOURCE OF UTILITIES
ULOCO - 1-800-632-4949
Power - Carolina Power and Light Co. (phone: [phone])
Natural Gas - North Carolina Natural Gas Corporation (phone: [phone])
Telephone - Southern Bell Telephone Co. (phone: [phone])
Water - City of Wilmington (phone: [phone])
Northside WWTP - 341-7891
EXISTING WWTP FACILITIES
The existing wastewater treatment facility consists of a preliminary
treatment unit, two trickling filters, two primary and two secondary
clarifiers, a chlorine contact basin, an effluent pump station, an anaerobic
digester complex and sludge drying beds.
Wastewater enters the plant through a metering station where the
influent flow is measured, then travels to the preliminary treatment unit.
Preliminary treatment consists of a comminutor or a handraked bar screen and
grit removal equipment.
After the preliminary treatment the wastewater is split in the
distribution box to the two treatment trains. Each treatment train consists
of a primary clarifier and a rock media trickling filter.
The effluent streams from the trickling filters are combined in a pump
station which includes the recirculation and secondary clarifier pumps. The
recirculation pumps pump wastewater to the primary clarifiers' effluent
boxes. The secondary clarifier pumps pump wastewater to the secondary
clarifiers.
Effluent from the secondary clarifiers are combined in a flash mix box
where chlorine is fed, then the wastewater flows through a chlorine contact
basin. The effluent from the chlorine contact is pumped to the confluence of
the Northeast Cape Fear River and Cape Fear River.

Black 6 Veatch
PRELIMINARY BASIS OF DESIGN MEMORANDUM
Wilmington, North Carolina 3
Northside WWTP Upgrade
BSV Project 03408.100
October 19, 1988
The facility was designed for 8 mgd and laid out to double the capacity
to 16 mgd with two additional primary clarifiers, two additional trickling
filters and two additional final clarifiers.
PROCESS DESIGN CRITERIA
A. WASTEWATER FLOW
1. Flow (mgd)
Present(1)
Design
Future
Annual Average
5.46
8.00
20.00
Maximum Month
7.32
12.00
30.00
Maximum Day
10.18
16.00
40.00
Maximum Peaking Factor
1.86:1
2.00:1
2.00:1
B. WASTEWATER CHARACTERISTICS
1. Biochemical Oxygen Demand (BOD), lb/day
Present(1)
Design
Future
7830(2)
13350(3)
41,700(4)
Annual Average
Maximum Month
8900
15350
50,000
Maximum Day
14150
24700
83,400
Maximum Peaking
Factor
1.81:1
1.85:1
2.00:1
2. Total Suspended
Solids (TSS),
lb/day
Annual Average
4750
10,000
33,350
Maximum Month
6200
13,500
66,700
3. Ammonia Nitrogen
(NH3), mg/l
Average Monthly
Average
15.6
20.0
28.0
4. Total Phosphorus (P), mg/1(5)
Average Monthly Average
(1) January 86 - August 88
(2) 172 mg/l
(3) 200 mg/l
(4) 250 mg/l
(5) January 88 - August 88
4.7
5.0 10.0

Black & Veatch
PRELIMINARY BASIS OF DESIGN MEMORANDUM
Wilmington, North Carolina
Northside WWTP Upgrade
4 B&V Project 03408.100
October 19, 1988
5. Temperature, C
Present Design
Minimum Monthly Average 14 12
Maximum Monthly Average 28 30
C. EXISTING EFFLUENT LIMITS
Parameters Weekly Average Monthly Average
Flow 8.0 mgd
BOD 45 mg/1 30 mg/l
TSS 45 mg/l 30 mg/l
Fecal Coliform 2000/100 ml 1000/100 ml
The following parameters must be monitored but no limits have been set.
Der mo for
Ammonia nitrogen
Total nitrogen
Total phosphorus
Dissolved oxygen
Temperature
Chlorine residual
pH
WASTEWATER TREATMENT PLANT UPGRADE
Effluent from the trickling filters will continue to be combined in the
existing secondary clarifier pump station. The existing pumps will be
replaced or modified to lift the wastewater to the new aeration basin.
Effluent from the aeration basin will flow to a new distribution box to
divide the flow to two new 4 mgd final clarifiers ,and two future 6 mgd final
clarifiers.
Sludge from the new final clarifiers will be recycled to the aeration
basin or wasted to a new sludge thickening facility by pumps in a new sludge
pump station. Scum from the final clarifiers will either be pumped back to
the aeration basin or pumped directly to the existing digester complex by new
scum pumps.
0

Black & Veatch
PRELIMINARY BASIS OF DESIGN MEMORANDUM
Wilmington, North Carolina 5 B&V Project 03408.100
Northside WWTP Upgrade October 19, 1988
The existing final clarifiers will be taken out of service.
The effluent from the new final clarifiers will be combined in a new
junction box then flow to the existing flash mix and chlorine contact basin.
Sludge from the final clarifiers will be thickened in a new facility
that will be designed to expand to treat 20 mgd.
The aeration basin will be designed to be expanded to provide a complete
mix activated sludge 20 mgd treatment plant. The blower building will be
designed to be expandable too.
A. SECONDARY CLARIFIER PUMP STATION
The existing pump station has three - 3 speed vertical turbine pumps
rated at 3500, 2800, 2100 gpn each at 12 TDH. The pumps will be replaced
to provide the following system:
Number of pumps 3
Type vertical turbine
Rated capacity 5600 gpm
Rated head
Motor horsepower
Normal operation
B. AERATION BASIN (Details of configuration will be provided after
preliminary design letter report is completed and
accepted.)
Number of Basins
1
Sidewater Depth, ft.
18
Organic Loading, mg/l
BOD average
81
TSS average
60
VSS average
45
Ma average
49
Hydraulic Loading, mgd
Q average 8
Q maximum 16

Black & Veatch
PRELIMINARY BASIS OF DESIGN MEMORANDUM
Wilmington, North Carolina 6
Northside WWTP Upgrade
Average
1. Retention Time, hours 3.5
Surface Area, sq. ft. 8665
Air Required, scfm
Mixing 3120
Maximum day 5750
Average Annual day 4120
Average
2. Retention Time, hours 5
Surface Area, sq. ft. 12,380
Air Required, scfm
Mixing 4,460
Maximum day 5,900
Average Annual day 4,780
Air Diffusers - Sanitaire coarse bubble or equal
Blowers
Number 2
Capacity, scfm 10750
Type Centrifugal
Horsepower 450
Controls Local manual
C. FINAL CLARIFIER DISTRIBUTION BOX
B&V Project 03408.100
October 19, 1988
Maximum
1.75
Maximum
2.5
A concrete flow distribution box shall be constructed to hydraulically
split the flow to the two new final clarifiers and two future final
clarifiers. Horizontal sharp crested weirs will split the flows. Stainless
steel fixed weir plates will be used for this purpose. Aluminum slide gates
will be used for bypassing a final clarifier.
0

Black & Veatch
PRELIMINARY BASIS OF DESIGN MEMORANDUM
Wilmington, North Carolina
Northside WWTP Upgrade
D. FINAL CLARIFIER
Number
Type
Diameter, ft.
Sidewater depth, ft.
Bottom slope
Flocculation well diameter,ft
depth, ft.
Collecting mechanism
horsepower
Flocculation drive
horsepower
Hydraulic Loading
Flow, mgd
Surface loading rate,
gpd/sf sq.ft.
Weir overflow rate,
gpd/ft.
Detention time, hours
Flocculation well
Total basin
Controls
Local manual
Overload device
Local light
Remote annunciation
Limit switch and
timers for skimming
device
Appurtenances and piping
Rotating weir skimming
device for scum removal
Inboard effluent weir and
baffle
Activated sludge piped
from hopper in bottom
of basin to secondary
sludge pump station
Scum piped to scum pump
station
7 B&V Project 03408.100
October 19, 1988
2
Centerfeed w/flocculating zone
90
14
1 in 12
35
10
1/2
5
Average
Maximum
4
8
705
1410
14981
29962
.43 .22
4.53 2.27

Black & Veatch
PRELIMINARY BASIS OF DESIGN MEMORANDUM
Wilmington, North Carolina
Northside WWTP Upgrade
E. SECONDARY SLUDGE PUMP STATION
Waste Activated Sludge:
Number of pumps
Type
Capacity, gpm
Pumping head, TDH
Motor Horsepower
Controls
Operation Period
Return Activated Sludge:
Number of pumps
Type
Capacity, gpm
Drive
Pumping head, TDH
Motor Horsepower
Controls
F. SCUM PUMP STATION
Number of pumps
Type
Capacity, gpm
Pumping head, TDH
Motor horsepower
Controls
BOA switch .
G. SLUDGE THICKENING FACILITY
8 B&V Project 03408.100
October 19, 1988
3
Non clog centrifugal
370
8 hrs/day
3
Non clog centrifugal
2300
2
Positive displacement piston
50
Details will be provided after preliminary design letter report is
completed and accepted.
H. SAMPLING SYSTEM
Sampling and Monitoring Facilities. The existing sampling system shall
be expanded to provide for sampling.of the new facilities. Sampling pumps
will be added for the aeration basin and final clarifier effluent. This will
provide total sampling for the following:

Black & Veatch
PRELIMINARY BASIS OF DESIGN MEMORANDUM -
Wilmington, North Carolina
Northside WWTP Upgrade
9 B&V Project 03408.100
October 19, 1988
Raw influent, continuous and discrete
Each primary clarifier effluent
Each trickling filter effluent
Each secondary clarifier effluent
I. EXISTING FACILITIES TO REMAIN IN SERVICE
1. PRIMARY CLARIFIER:
Number 2
Diameter, ft. 85
Sidewater depth, ft. 12
Flocculation well diameter, ft. 35
2. TRICKLING FILTER:
Number 2
Diameter, ft. 160
Media rock
Media depth, ft. 5.25
3. SECONDARY CLARIFIER:
The existing clarifiers will be examined for possible use as
chlorine contact basins.
Number 2
Diameter ft. 80
Sidewater depth, ft. 10

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