NC0026000_Plan of Action_20170522

TECHNICAL MEMORANDUM
FOR THE
Town of Tabor City Wastewater Treatment Plant
Facility Assessment and Corrective Action Plan
WKD Project No.: 20150187.00.CL
Issued: March 31, 2017
FOR
Town of Tabor City
PO Box 655
Tabor City, NC 28463-0655
Copyright ©, WK Dickson & Co., Inc. All rights reserved. Reproduction or use of the contents of this document;
additions or deletions to this document, in whole or in part without written consent of WK Dickson & Co., Inc., is
protubited. Only copies from the original of this document, marked with an original signature and seal shall be
considered to be valid, true copies.
WK Dickson & Co., Inc.
616 Colonnade Drive
Charlotte, North Carolina 28205
(t) 704- 334- 5348
www.wkd!dmn.com
NC License No. F-0374

Table of Contents
Section Page
Section 1-Introduction 1-1
Section 2-Facility Assessment 2-1
Section 3-Corrective Action Plan 3-1
Appendix A — Anticipated Schedule A-1
Appendix B — W WTP Drawing and Hydraulic Profile B-1
Appendix C — W WTP Proposed Schematic C-1
Appendix D — Mercury Minimization Plan D-1
W I� Town of Tabor City
D I C I<SO N Facility Assessment and Corrective Action Plan
commuNW intwsb tuts consuitcnK 20150187.00.CL
Issue Date: March 31, 2017
Page

TaborClty
6MMMIM—,.
Section 1- Introduction
Section 1 - Introduction
The Town of Tabor City is located in Columbus County, North Carolina. Columbus County is
located in the southeastern part of the state along the South Carolina border and separated from
the Atlantic Ocean by Brunswick County. The Town population is approximately 4,300 according
to the most recent statistics. The Town is accessed by US Highway 701, NC Highway 904 and
NC Highway 410. The Carolina Southern Railroad passes north to south through the center of
Town. Neighboring municipalities include Fair Bluff, Chadboum, Whiteville, and Loris, South
Carolina.
The Town of Tabor City owns and operates the town of Tabor City Wastewater Treatment Plant
(W WTP), located at 244 US Hwy 701 Bypass N. Initial construction of the Tabor City W WTP was
completed in 1973, making the plant more than 42 years old. Pressure filters were added in 1999
to assist with solids removal from the plant effluent; however the filters were never operated
consistently and were abandoned years ago. In 2007, a major plant upgrade was undertaken,
which saw replacement of the two existing aeration basins with new concrete aeration basins,
construction of a lined equalization basin, and upgrades to the headworks including a new auto
screening system, upgraded grit removal, and a new flow sputter box. Currently, the plant has a
permitted capacity of 1.1 MGD and consists of the following components: a triplex influent
pumping station, mechanical screening, grit removal, equalization basin, two aeration basins
(upper and lower), two secondary clarifiers (upper and lower), influent and effluent samplers,
gaseous chlorine/sulfur-dioxide feed system, influent and effluent ultrasonic flow meters, a back-
up power generator, aerated sludge holding basin, and chlorine contact basin. W.K. Dickson was
retained to perform a Facility Assessment and Corrective Action Plan of the wastewater treatment
plant as defined by the permit (NC0026000). Overall objectives of the Plan are as follows:
1. Evaluate the physical and operational condition and performance of the entire treatment
facility. The assessment shall identify deficiencies and operational difficulties in the
treatment facility which affect performance or permit compliance, and identify potential
improvements to correct those shortcomings. Included in the facility Assessment the
Permittee shall:
a. Evaluate the adequacy of the entire headworks at average and peak flows.
b. Evaluate the cause of the hydraulic issue at the upper secondary clarifier (#1).
2. Develop a Corrective Action Plan (CAP) which includes a strategy for the repair,
modification, and/or replacement of deficiencies in the treatment facility in order that
P%wI< Town of Tabor City
D I C I<SO N Facility Assessment and Corrective Action Plan
cmnmunlly inaosswcNre ccnwHwft 20wch 3 , 2017
Issue Date: March 31, 2017
Page 1-1

Section 1 - Introduction
equipment functions as designed and in order to consistently comply with the effluent
limitations of this permit. The CAP shall:
a. Identify corrective actions needed in the headworks structures and establish an
effective and reliable diversion plan to the side -stream surge basin.
b. Identify actions needed to rehabilitate the upper secondary clarifier (#1) and its
connective piping to function as designed.
c. Identify operational changes or strategies needed to improve facility performance.
d. Provide specific dates for completion or implementation of each action.
The Facility Assessment was conducted on December 8-9, 2015. During the evaluation each unit
process was carefully inspected for functionality and efficiency with the overall goal to assess the
operational performance of the Town of Tabor City WWTP.
Figure 1-1 Aerial view of the Town of Tabor City Wastewater Treatment Plant.
End of Section
Town of Tabor City
DIIC i<SO N Facility Assessment and Corrective Action Plan
communtty rottosm Lure consunonts 20150187.00.CL
Issue Date: March 31, 2017
Page 1-2

Fmi
Section 2 — Process Evaluations
Section 2 — Facility Assessment
Each of the unit processes are required by regulatory requirements to have a sufficient number of units to ensure
that if the largest flow capacity unit was out of service, the remaining units will have a design flow capacity of
50% the total design average flow. The unit processes have each been evaluated on their condition and operation
which may include:
♦ Defects
♦ Properly operating unit processes and components
♦ Up to date maintenance
♦ Neat and orderly workspaces
A. Triplex Influent Pumping Station
The mechanical screen is designed to remove solids larger than 0.125 inches from the wastewater stream
flow. The mechanical screen automatically cleans itself and is designed to run routinely either based on
a timer or differential water level, but it is not designed to run constantly. During the evaluation it was
observed that the level transducers may not be in proper working order. The mechanical screen is
currently being operated on timers. Wastewater enters the WWTP through a 24-inch ductile iron pipe
(DIP). The plant influent comes into a pump station consisting of three large pumps. One 50 horsepower
(hp) pump, one 40 hp pump, and one 30 hp pump. The 50 hp and 40 hp pumps are the main pumps,
with the 30 hp pump only used as a backup as necessary. The flow enters through an initial wet well
with a coarse bar screen at the bottom of the approximately 20 feet deep well. The flow is then split to
two other wet wells just behind the first. Influent Pumps #1 & #2 (40 hp and 50 hp) pull from one well
while backup Influent Pump #3 pulls from the other.
During the facility assessment, it was noted that the bar screen in the initial wet well was full of large
rags and debris. An operator is required to manually scrape the screen numerous times daily to remove
the debris.
IICKSON
communRy nuoMtr Iurs CWsullonb
Town of Tabor City
Facility Assessment and Corrective Action Plan
20150187.00.CL
Issue Date: March 31, 2017
Page 2-1

Section 2 — Facility Assessment
Figure 2-1 Influent Triplex Pump Station
B. Flow Equalization Basin
An HDPE lined Equalization (EQ) Basin is used at the WWTP to divert flow from the influent pump
station during extreme high flow situations. The basin is capable of storing up to 1.7 MGD of water. The
EQ basin contains two floating aerators and a floating decanter. Currently, the operator is required to
WD IICKSON
communft InoosUucture consultants
Town of Tabor City
Facility Assessment and Corrective Action Plan
20150187.00.CL
Issue Date: March 31, 2017
Page 2-2

u
Section 2 — Facility Assessment
manually open or close the valves leading to and from the EQ basin as high flows enter and recede from
the plant.
Figure 2-2 Flow Equalization Basin
C. Headworks
The Headworks at the Tabor City WWTP consist of a mechanical bar screen and a grit removal system.
The mechanical bar screen is a Mellegard Cross Screen, a large step type screen, with self-cleaning
capabilities. The openings on the screen can range in size from 0.5 — 6 millimeters (mm). The mechanical
bar screen begins operation any time a pump at the influent pump station turns on. Observations of the
bar screen at both peak and average flow showed that the screens operate frequently, even if screening
is not necessary at the time. However, large quantities of grit were not removed during the self-cleaning
operation of the mechanical screen. Whatever grit and debris was removed during self-cleaning of the
screen was captured in a large garbage dumpster. Only a very small amount of debris was observed
coming off the screen during the plant assessment. The dumpster had been emptied 2 weeks before the
WK Dickson team visited the plant and during our assessment, the dumpster was less than 1/10th full.
WD IICKSON
community IMeoiftmwre cwtutionR
Town of Tabor City
Facility Assessment and Corrective Action Plan
20150187.00.CL
Issue Date: March 31, 2017
Page 2-3

Section 2 — Facility Assessment
Figure 2-3 Mechanical Bar Screen
During the plant assessment a peak flow of approximately 2 MGD was observed twice while assessing
the mechanical bar screen. The rubber lining the sides of the mechanical step bar screen was not flush to
the screen, but instead curled up in certain locations. It was noted that, especially during peak flow, a
steady flow of wastewater was moving through the openings left by the warped rubber and was not
being properly screened. Also, there was grit and debris built up in the overflow chamber of the bar
screen, which is used in high flow situations when the 3rd influent pump turns on.
Figure 2-4 Overflow Chamber
WDIICKSON
commuolN InM1atleuCtute cMsullOnK
Town of Tabor City
Facility Assessment and Corrective Action Plan
20150187.00.CL
Issue Date: March 31, 2017
Page 2-4

Section 2 — Facility Assessment
Figure 2-5 Backside of Mechanical Screen
After passing through the bar screens, the wastewater flow moves to a grit removal system. The system
is a rolling grit removal system manufactured by Walker Process Equipment. As the wastewater enters
the grit removal tank, it is pre -aerated to assist with separation of the grit from the wastewater flow. As
the grit settles in the tank, it is pumped to an inclined screw grit washer located on the end of the grit
removal tank. The accumulated grit is conveyed through grit washer to a hopper where it is collected in
a large dumpster. Though a large amount of grit was observed in the bottom of the grit removal tank,
large quantities were not being collected in the dumpster. The on -site operator stated that the collector
dumpster is cleared of grit very infrequently, maybe once a month.
IDIICKSON
communrry wicstruclure cO sullcnh
Town of Tabor City
Facility Assessment and Corrective Action Plan
20150187.00.CL
Issue Date: March 31, 2017
Page 2-5

TaborCity
Figure 2-6 Grit Removal System
Section 2 — Facility Assessment
After the grit removal system, the flow is sent to a flow splitter box which separates the flow for the
upper and lower extended aeration clarifiers. During the plant assessment, the wastewater entering the
flow splitter box was observed to be a dull blue-green color. According to the operators, this coloring of
the water happens often, at least 50% of the time. The coloring is believed to be due to upstream industrial
user located near the W WTP.
Figure 2-7 Flow Splitter Box
WDIICKSON
co munHy MM1a3huclure co Mamf
Town of Tabor City
Facility Assessment and Corrective Action Plan
20150187.00.CL
Issue Date: March 31, 2017
Page 2-6

Section 2 — Fqcih!3, Assessment
D. Upper Aeration Basin & Clarifier #1
The WWTP employs an activated sludge treatment process, which is designed to be split between two
(2) aeration basins and 2 clarifiers. Biological treatment begins in the Aeration Basins, which receive flow
from the flow sputter box after the grit collection system. Upper Aeration Basin #1 is a large rectangular
concrete basin, 160ft x 117ft. The sides are sloped. Three (3) floating mechanical surface aerators provide
mixing of the aeration basin and aeration of the wastewater. During the plant assessment, only 2 of the
surface aerators in the upper basin were operational, so it was difficult to gauge how efficient the mixing
in the basin was. There were no Variable Flow Drives (VFD's) on the aerators for the upper aeration
basin, although there are VFD's on the lower aeration basin #2 surface aerators.
Figure 2-8 Upper Aeration Basin #1
Aeration Basin #1 was not treating any wastewater during the WK Dickson site visit. Because the upper
clarifier #1 was not operational, the upper aeration basin was being used as a holding tank for water
diverted during heavy rains. During observation of the aeration basin, it was noted that the return
activated sludge (RAS) line, which returns sludge from the Upper Clarifier #1 back to the aeration basin
to maintain the activated sludge process, enters the aeration basin almost directly adjacent to the one of
the effluent weirs from the aeration basin to Clarifier #1. There is approximately 2 feet of spacing in
between the RAS line and effluent weir. This indicates that RAS flow from the clarifiers is not getting
sufficient aeration or detention time before returning to clarification.
WDIICKSON
commumiy mnosvucmre consmtonts
Town of Tabor City
Facility Assessment and Corrective Action Plan
20150187.00.CL
Issue Date: March 31, 2017
Page 2-7

r,
ZaborCjty
I�
Figure 2-9 Upper Aeration Basin #1 Effluent Weir
Section 2 — Facility Assessment
Upper Clarifier #1 was not in operation during the site visit and plant assessment. Tabor City has often
had issues with this clarifier. Wastewater from Upper Aeration Basin #1 flows through 8-inch D1P to
Upper Clarifier #1, which is approximately 60 feet in diameter. Solids are separated by gravity and the
clarifier effluent exits the clarifier across a v-notch weir. Solids that settle to the bottom of the clarifier are
removed by RAS/WAS pumps. The RAS is pumped via a 6-inch force main (FM) back to the Upper
Aeration Basin #1. The potential short circuiting issue that arises from the location of this RAS line is
discussed in the previous paragraph. Another issue is that the RAS control valve was not able to be
located. Although these RAS pumps and line have not been operational in more than a year, the plant
operators have no way of controlling the RAS flow rate, or adjusting to meet the operational needs of the
WWTP. The Waste Activated Sludge (WAS) is supposed to be pumped through a 6-inch FM to the
Aerobic Digester. However, a small plastic 4-inch PVC pipe from the upper pump station to the Aerobic
Digester appears to be the line used to convey the WAS. According to the operator, the WAS line for the
upper clarifier #1 has not been in operation in over a year.
WD IICKSON
COIIImUnllr IMOW.a WEB consultants
Town of Tabor City
Facility Assessment and Corrective Action Plan
20150187.00.CL
Issue Date: March 31, 2017
Page 2-8

Section 2 — Facility Assessment
Figure 2-10 #1 Clarifier Influent Box
In regards to the operation of the Upper Clarifier #1, a former operator indicated that when the clarifier
has been drained in the past, large rags and debris have been found in the 8" DIP line leading to the
clarifier. Some sand/grit and other solids were also seen. A jet flusher has been inserted into the piping
to clean it; however it would regularly become stuck. The pipe enters at the bottom of the clarifier and
enters after a sharp bend.
Figure 2-11 #1 Clarifier
�D IICKSON
community ineosiruclure consunan%
Town of Tabor City
Facility Assessment and Corrective Action Plan
20150187.00.CL
Issue Date: Marcie 31, 2017
Page 2-9

Section 2 — Facility Assessment
E. Lower Aeration Basin & Clarifier #2
The Lower Aeration Basin #2 is a rectangular concrete basin, 198ft x 96ft, with sloped sides. Three (3)
floating mechanical surface aerators provide mixing of the aeration basin and aeration of the wastewater.
Each of the aerators have a VFD, however the VFD's controls are not tied to the information gathered
from the DO probe in the basin. During the assessment, it was noted that the most efficient mixing in the
lower aeration basin took place in the middle of the basin. The observation was made that the sides of
the basin had low mixing and some sludge was settled along the sides.
Figure 2-12 Lower Aeration Basin
Because the upper activated sludge train was non -operational, all wastewater treatment was being
performed in the lower aeration basin and clarifier #2. Wastewater flow from the lower aeration basin is
conveyed through an 8-inch DIP to the approximately 48 feet diameter Lower Clarifier #2. Similar to the
process and setup in the upper clarifier, solids are separated by gravity and the clarifier effluent exits
through a v-notch weir. The solids that settle to the bottom of the clarifier are removed through
RAS/WAS pumps. The RAS/WAS process in the Lower Clarifier #2 is operational, unlike in the upper
clarifier. The RAS is pumped through a 4-inch FM to a manhole where it is mixed with influent flow
before entering the lower aeration basin through an influent weir. The WAS is pumped through a 4-inch
FM to the Aerobic Digester. The RASJWAS flow in the lower clarifier #2 is controlled by an on/off switch.
The flow can be increased or decreased through the valves.
WD IICKSON
commune InhOslrucWre Consullann
Town of Tabor City
Facility Assessment and Corrective Action Plan
20150187.00.CL
Issue Date: March 31, 2017
Page 2-10

Section 2 — Facility Assessment
Figure 2-13 Lower RAS
The Lower Clarifier #2 does cease operating correctly at times, according to plant operators. Heavy
amounts of duckweed were observed during the plant assessment visit. The duckweed can clog up the
clarifier so that it does not drain or pump properly.
Figure 2-14 #2 Clarifier
WDIICKSON
cammunlry Intia,iructure cww11an%
Town of Tabor City
Facility Assessment and Corrective Action Plan
20150187.00.CL
Issue Date: March 31, 2017
Page 2-11

'jabo Section 2 — Facility Assessment
F. Aerobic Digester
The two WAS lines bring waste activated sludge to the concrete lined Aerobic Digester from the upper
and lower clarifiers. A 15 hp suspended mixer is used to mix the sludge. The mixer is run 2 to 3 times a
week, and continuously during wasting. The on -site operator indicated that there is a short or some kind
of malfunction in the electrical controls for the mixer that prevents it from running on a continuous basis
or on auto. It is clear from observation that sufficient mixing is not achieved in the digester. The layer of
sludge on the top is very thick and the color could indicate anaerobic conditions. Though there is a sludge
loading dock for sludge removal, it is not used. A truck comes periodically to draw sludge off the top of
the digester.
Figure 2-15 Aerobic Digester
G. Disinfection
Treated wastewater from the clarifiers flows to chlorine contact basin. Chlorine and sulfur from large
cylinders are used to disinfect the effluent prior to discharge. Calculations show that the chlorine contact
basin detention time is within the accepted limit at 1.1 MGD flow. Instantaneous peak flows of almost 2
MGD were observed during the plant assessment. At these flows, the contact time is only about half of
what is required. According to the operators on site, the concrete walls of the chlorine contact basin are
weak and crumbling. Leaks have developed as a result.
WDIlCKSON
community Initastrudare consultants
Town of Tabor City
Facility Assessment and Corrective Action Plan
20150187.00.CL
Lssue Date: March 31, 2017
Page 2-12

Figure 2-16 Disinfection
End of Section
W DIIC KSON
communal InM1wtrucsure consuncnts
Section 2 — Facility Assessment
Town of Tabor City
Facility Assessment and Corrective Action Plan
20150187.00.CL
Issue Date: March 31, 2017
Page 2-13

Section 3 Corrective Action Plan
Section 3 - Corrective Action Plan
Influent Pumping, Flow Equalization Basin, and Headworks
For the Tabor City W WTP to achieve at optimal treatment, changes and updates will be required.
In the influent pump station, flow equalization (EQ) basin, and headworks areas, the following
corrective actions are proposed:
• Install VFD's on the influent pumps and same size motors to allow a constant flow of
wastewater into the plant. Schedule: Completed in conjunction with CAP and permit
approvals, funding availability, and construction schedule as approved by DWI.
• Rotate use evenly between all three influent pumps to cut down on one pump becoming
more fatigued and having a potentially shorter useful life. Schedule: Completed in
conjunction with CAP and permit approvals, funding availability, and construction
schedule as approved by DWI.
• Install automated valves on the piping between the Influent Pump Station and EQ basin
to improve the reliability of diverting flow to the basin as needed so that influent flow to
the plant will stay at a constant level. Schedule: Completed in conjunction with CAP and
permit approvals, funding availability, and construction schedule as approved by DWI.
• Add a staff gauge to the EQ basin to regulate levels within the basin. Schedule:
Completed in conjunction with CAP and permit approvals, funding availability, and
construction schedule as approved by DWI.
• Evaluate the options for relocation of existing headworks during the design process of
the proposed upgrades to the facility to be located prior to the influent pump
station. This evaluation shall include relocation of headworks, or resizing within same
location of current configuration to be able to best accommodate design flows and to
meet the intent of the original design. This may include replacement of either bar screen
and grit removal or neither depending upon design evaluation and concurrence with
DEQ. Schedule: Completed in conjunction with CAP and permit approvals, funding
availability, and construction schedule as approved by DWI.
• Efforts are being made to identify and address I/I sources in the collection system.
Schedule: Completed in conjunction with CAP and permit approvals, funding
availability, and construction schedule as approved by DWI.
WD IICKSON
community
Town of Tabor City
Facility Assessment and Corrective Action Plan
20150187.00.CL
Issue Date: March 31, 2017
Page 3-1

C
Aeration Basins and Clarifiers
Section 3 Corrective Action Plan
Many hydraulic issues arise from the continued operational problems with the Upper Aeration
Basin and Clarifier #1. Proposed corrective actions for these areas include:
• Move RAS piping from location at end of Clarifier #1 directly adjacent to effluent weir to
area that is more conducive to proper mixing/aeration and detention times for RAS flow.
Suggested location is North side of Upper Aeration Basin #1 near the start of the tank,
directly across from the influent flow weir. Re-laying this pipe will remove the possibility
of short circuiting of the RAS flow. It is believed that this short circuiting may have caused
solids over -loading in Upper Clarifier #1. Schedule: Completed in conjunction with CAP
and permit approvals, funding availability, and construction schedule as approved by
DWI.
• Install valves on piping and flow meters to be able to control RASIWAS flow to/from
Upper Clarifier #1 (also if there is not a flow meter on RAS/WAS valves for Lower Clarifier
#2, install flow meter on that piping as well). Schedule: Completed in conjunction with
CAP and permit approvals, funding availability, and construction schedule as approved
by DWI.
• Dig and replace/reconfigure piping leading into Upper Clarifier #1. Use larger pipe sizes
and less severe bend angles to reduce possibility of pipes clogging. For all piping between
Upper Aeration Basin #1 and Upper Secondary Clarifier #1 with a complete clarifier
redesign and rehabilitation. Schedule: Completed in conjunction with CAP and permit
approvals, funding availability, and construction schedule as approved by DWI.
• A condition assessment will be made on all pipes with low flow or that are suspected of
clogging. Identified problems will be addressed to ensure proper flow rates are
maintained. WAS piping shall also be evaluated and addressed for redesign and
rehabilitation. Schedule: Completed in conjunction with CAP and permit approvals,
funding availability, and construction schedule as approved by DWI.
For Lower Aeration Basin #2:
• Tie DO level results from DO probe in Lower Aeration Basin #2 to existing VFD's on the
three floating aerators. This will allow for more efficient power usage so that aerators are
not operating continuously and will only turn on as needed to keep oxygen at required
levels. Schedule: Completed in conjunction with CAP and permit approvals, funding
availability, and construction schedule as approved by DWI.
PSWTown of Tabor City
I C I<SO N Facility Assessment and Corrective Action Plan
community mtroarualiw• c=uuann 20150187.00.CL
Issue Date: March 31, 2017
Page 3-2

Section 3 Corrective Action Plan
Aerobic Digester and Chlorine Contact Basin
Rehabbing the digester and chlorine contact basin will help improve plant performance.
Corrective actions for these areas include the following:
• Replace the mixer in the Aerobic digester with a larger size mixer/aerator. This will result
in better mixing and aeration for the aerobic digester. Schedule: Completed in
conjunction with CAP and permit approvals, funding availability, and construction
schedule as approved by DWI.
• Coat the walls of the chlorine contact basin with a coal tar epoxy to help protect the basin
walls from the corrosive nature of chlorination. Schedule: Completed in conjunction with
CAP and permit approvals, funding availability, and construction schedule as approved
by DWI.
• Reconfigure the disinfection system to allow a portion of the system to be out of
commission for maintenance without affecting disinfection capabilities during ideal flow
conditions. Schedule: Completed in conjunction with CAP and permit approvals, funding
availability, and construction schedule as approved by DWI.
• Evaluation of disinfection system to include assessment of conversion of gaseous chlorine
to liquid sodium hypochlorite, with considerations and evaluation of flow paced dosing
for both options. Schedule: Completed in conjunction with CAP and permit approvals,
funding availability, and construction schedule as approved by DWI.
WD ICKSON
COmmVnNy M(IOfINChIfB COniultanif
End of Section
Town of Tabor City
Facility Assessment and Corrective Action Plan
20150187.00.CL
lssue Date: March 31, 2017
Page 3-3

IIICKSON
cammumly In11O3huclure canwtlann
Appendix - A
Appendix A - Anticipated Schedule
Town of Tabor City
Facility Assessment and Corrective Action Plan
20150187.00.CL
Issue Date: March 31, 2017
Page A-1

Appendix A - Anticipated Schedule
Town of Tabor City
W WTP Rehabilitation
Clean Water State Revolving Loan Fund
CS 370609-01
Below is the anticipated project schedule as provided by Municipal Engineering Services
Company, P.A.
Design Package Submittal, November 3, 2017
Design Package Approval, March 2, 2018
Award Construction Contract, August 6, 2018
Notice to Proceed, September 28, 2018
Finish Construction, November 29, 2019
IDIICKSON
cg unily Inhasirualure com0anb
Town of Tabor City
Facility Assessment and Corrective Action Plan
20150187.00.CL
Issue Date: Mardi 29, 2017
Page: 1

Appendix - B W WTP Drawing and Hydraulic Profile
WD IICKSON
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A}2l,en
Town of Tabor City
Facility Assessment and Corrective Action Plan
20150187.00.CL
Issue Date: March 31, 2017
Page B-1

RECORD DRAWINGS OCTOBER 2009
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G-11
17

WDIICKSON
communM Inf,owuclure cwsuuonb
Appendix - C
Appendix C — W WTP Proposed Schematic
Town of Tabor City
Facility Assessment and Corrective Action Plan
20150187.00.CL
Issue Date: Much 31, 2017
Page C-1

Grit
Influent Pump Station
Barscreen
Collector
Splitter
Box
Lower
Upper
Equalization
Aeration
Aeration
Basin
Basin #2
Basin #1
Relocate RAS line farther from effluent
locations to increase mixing, detention
time, and decrease short circuiting.
Install Valves and Flow
Monitors to better regulate flow.
i
Aerobic
Lower
Upper
Sludge
Secondary
Secondary
Digester
Clarifier #2
Clarifier #1
i
Chlorine
Sludge
Contact
Loading
Chamber
Legend
►— Existing Lines
—►— Proposed Lines
NOT TO SCALE
-_—
Tabor City
Iabo
WWTPProposedSchematic
/^DICKSON
March 2017
mint aehuchxe ca wnanro
--
WKD Project No.: 20150187.00.CL

WDIICKSON
community Intros wute cO svlfants
Appendix - D
Appendix D -Mercury Minimization Plan
Town of Tabor City
Facility Assessment and Corrective Action Plan
20150187.00.CL
Issue Date: March 31, 2017
Page D-1

TOWN TABOR CITY WASTEWATER TREATMENT PLANT
MUNICIPAL MERCURY MINIMIZATION PLAN
June 29, 2016
SECTION I -PURPOSE
The purpose of this Mercury Minimization Plan ("MMP") is to describe best management practices through
which the Town of Tabor City Wastewater Treatment Plant will seek to reduce the amount of mercury
discharged into its system and, ultimately, to the environment. The MMP compiles mercury reduction -
related efforts to -date and potential future action items. It is designed to be a working document to help
guide Town of Tabor City (Town) in its efforts to control mercury loadings discharged into its Publicly -
Owned Treatment Works (POTW) by users of the sewer system. Such a reduction in loadings to the sewer
system should translate to a reduction in the amount of mercury which is discharged from the treatment
plant. The management practices summarized below may also help control some of the mercury reaching
our storm sewer system as well.
SECTION II — FACILITY DESCRIPTION
The Town operates a publicly owned treatment works (POTW), including a collection system and
wastewater treatment plant (W WTP), that serves the Town of Tabor City, North Carolina.
The Town W WTP operates under NPDES Permit NCO026000 with a design capacity 1.1 mgd and average
daily flows of approximately 0.3 to 0.4 mgd and an apparent peak flow of approximately 1.0 mgd. The
treatment process includes two (2) biological treatment trains with the following components:
• Triplex influent pump station
• Influent Parshall flume with ultrasonic flow meter
• Mechanical bar screen and by-pass manual bar screen
• Grit removal system
• Side -stream emergency surge basin (1.7 MG)
• One (1) extended -aeration activated sludge basin (AB 41 — 1.177 MG) with mechanical floating
aerators
• One (1) contact stabilization basin (AB 42 — 1.1665 MG) with mechanical aerators
• Two (2) clarifiers (Clarifier #1 — 60' diameter with 12' SWD, Clarifier 42 50' diameter x 9'
SWD)
• Gaseous chlorine and sulfur dioxide feed systems for chlorination and dechlorination
• Chlorine contact basin with ultrasonic flow meter
• Aerated sludge holding basin
• Back-up power generator
Most municipal treatment plants are not designed to remove mercury and it is exceedingly expensive to do
so to very low levels. Incidental mercury removal occurs through typical municipal treatment with trace
levels of mercury (and other metals) ending up in solids removed from the raw wastewater.
Mercury is not used in the treatment processes at the W WTP but may be introduced into the sewer system
through a variety of sources, such as discharges from industrial users, laboratories, dental clinics, medical
facilities (i.e. hospitals, clinics, nursing homes and veterinarians), schools, and hauled waste. Residual
deposits of mercury are also possible in the sewer system from historic practices. Finally, trace amounts

from household products and atmospheric deposition (both wet and dry) contribute to sewer system
mercury loadings.
While there is typically some mercury contributed to public sewer systems statewide, it is usually in minute
quantities and comprises a tiny portion of the already insignificant statewide loading for all point sources -
just two percent of the annual mercury loadings to all State waters.
Potential non -domestic sources of mercury within the Town sewer system typically include local industries,
medical facilities, dental offices and schools. The Town has a current population of approximately 4,000
people with an area of approximately 3.2 square miles. Local industrial employers within the Town include
the following:
Company Name
Tvoe of Business
Number of Employees
Atlantic Corporation
Paper Converters
210
Tabor City Lumber
Wood Processing
30
Filtec Precise, Inc.
Nylon Spinning
45
Atlantic Automotive Enterprises
Auto Parts
21
*Source— www.taborci .or indus /
The Town has three (3) schools consisting of Tabor City Elementary School, Tabor City Middle School
and South Columbus High School. Major medical facilities include South Columbus Medical Center.
Between January 2010 and May 2015, the mercury data was evaluated with the annual average found to be
above the Water Quality Based Effluent Limitation (WQBEL) of 0.12ng/L, 13 times. The data also was
found to be above the Technology Based Effluent Limitation (TBEL) of 47 ng/L, 2 times. Accordingly, the
effluent limit of 0.12 ng/L is maintained within the NPDES Permit at a sampling frequency of monthly.
Since the facility has shown significantly high concentrations within the effluent with 97% of samples
between January 2010 and May 2015 greater than 1 ng/L, a Mercury Minimization Plan (MMP) is required.
SECTION III — PROGRAM PLAN
A. EVALUATION OF POTENTIAL NON -DOMESTIC SOURCES CONTRIBUTING
MERCURY TO THE POTW
Within 24 months from the NPDES required 180-day period for development of an MMP (NPDES Permit
effective date), the Town will evaluate available information to assess the potential for non -domestic users
of the sewer system to contribute mercury to the system. The information to be reviewed may include: (1)
POTW influent and effluent mercury data and trends; (2) industrial user permits and associated mercury
monitoring data; (3) Toxics Release Inventory (TRI); (4) state hazardous site registry and the National
Priority List relating to mercury contamination; and (5) historical records of industrial sites which have
contributed mercury loadings to the sewer system.
The Town will also survey and evaluate the following common sources of mercury in its service area: (1)
dentist offices; (2) hospitals; (3) laboratories; (4) auto recyclers; and (5) other potential sources of mercury
based on existing information.
The Town will request that industrial related users review mercury concentrations in high -volume process
chemicals and demonstrate that the mercury concentrations are below industry average. The Town will
also request that alternative sources for chemicals be explored if the mercury levels are determined to be

significantly higher than would normally be expected. If the mercury levels continue to be elevated and
continue to create compliance issues with the permit, a pretreatment program will be implemented.
The evaluation of potential non -domestic sources of mercury to the sewer system will be updated every
five years, as warranted by prior sampling results and any additional new potentially significant sources to
the system.
B. ADDITIONAL CONTROL MEASURES
This MMP identifies reasonable and cost-effective control measures to minimize mercury being discharged
into the POTW. Below is a listing of initial BMPs for this POTW.
Pollution Prevention
Substances used at the WWTP will be evaluated to determine if they contain mercury or mercury -based
compounds. Any such chemicals will be evaluated for substitution with non -mercury -containing
substances.
Housekeeoine. Spill Control and Collection, and Education
The Town will develop procedures to minimize the possibility of any spill or release at the WWTP
involving mercury containing substances. The Town will add mercury identification and proper disposal
to ongoing and future operator training procedures.
Public Outreach
The Town will make available educational information regarding sources of household mercury and
appropriate use/disposal practices. This information may be posted on the Town's website and mercury
public education promoted through local news articles and flyer distribution within sewer bills. The
availability of this information will be highlighted within one (1) year as an outreach to the Town's
customers. The Town will also facilitate public awareness regarding community collection points for
mercury -containing products from residents/customers for proper disposal. Periodic reminders of such
collection programs will be provided as part of the Town's ongoing public outreach.
Laboratory Practice
The Town currently contracts laboratory operations for purposes of complying with state and federal
monitoring and sampling requirements through a private laboratory service. The laboratory is a potential
source of small quantities of mercury -containing compounds. The Town proposes to require the contract
laboratory employees be trained in the proper handling and disposal of these materials as part of their
contract service. The laboratories will also be requested to replace mercury thermometers with non -
mercury thermometers, whenever practical.
C. TRACKING AND MONITORING
In order to assess the implementation of the control measures, the Town proposes to undertake the following
evaluations beginning after the first full year that this MMP is implemented:
1. Survey annually at least ten percent (10%) of any non -domestic users identified as
possible significant sources of mercury to the POTW;
2. Track the implementation of the programs outlined above;

3. Monitor influent mercury at least annually. Require significant non -domestic sources of
mercury to monitor periodically, as warranted; and
4. Measure effluent mercury as required by the NPDES permit.
These efforts will allow the Town to establish a baseline of influent and effluent mercury levels to assist in
identifying any trends in mercury contributions from domestic and non -domestic users of the sewer system.
This baseline will be tracked annually.
Begin mercury sampling upstream and downstream of the Town's wastewater treatment plant outfall to
further evaluate the potential instream mercury contribution by the Town and identify the mercury reduction
potential.
SECTION IV — IMPLEMENTATION OF CONTROL MEASURES
The Town will implement the control measures summarized in Section III over the permit term and will
update this MMP as warranted. The Town has already evaluated an industrial site and reviewed disposal
management practices with entity and implemented new policies.
SECTION V - REPORTING
A summary of the MMP activities will be submitted as part of the NPDES permit renewal process.