NC0063096_Engineering Alternatives Analysis_20110812

IV600( 30t
Town of Holly Springs
Wastewater Discharge Alternatives
Evaluation & Expansion
Engineering Alternatives Analysis
dMP
Tru: TOwn OF
Holly
Springs
CAROI.INA
Richard G. "Dick" Sears, Mayor
James Cobb
Tim Sack
Chet VanFossen
Linda Hunt Williams
Parrish "Ham" Womble
August,2011
DAVIS -MARTIN -POWELL & ASSOCIATES
ENGINEERING • LAND PLANNING -SURVEYING
6415 Old Plank Road, High Point, NC 27265
[phone] 1 Fax [phone] w .drop-inc.com
CAROUNA 3040 NC 42 West, Clayton, NC 27520
ECOSYSTEMs_ Imc [phone] 1 Fax[phone]

Town of Holly Springs
Wastewater Discharge Alternatives
Evaluation & Expansion
Engineering Alternatives Analysis
Responsible Agency: Department of Environment & Natural Resources
Division of Water Quality — Planning Section
1617 Mail Service Center
Raleigh, NC 27699
Consultants
Hannah Stallings, SEPA Coordinator
[phone]
han nah.stallings(o) ncden r.0 ov
Davis -Martin -Powell & Associates, Inc.
6415 Old Plank Road
High Point, NC 27265
NC Firm F-0245
Michael L. Slusher, PE
[phone]
MSIu sher(&dm p-inc.com
Carolina Ecosystems, Inc.
3040 NC 42 West
Clayton, NC 27520
Phil May
[phone]
Phil. May(cDcarolinaeco. com
Owner: Town of Holly Springs
128 South Main Street
PO Box 8
Holly Springs, NC 27540
Stephanie L. Sudano, PE
[phone]
stephanie.sudano(a)hollvspringsnc. us

TABLE OF CONTENTS
Section Page
Contents
Table of Contents
Abbreviations and Acronyms......................................................................................................
iv
i. Project Summary .............................................................................................................1
i.1 Introduction..........................................................................................................1
i.2 Background..........................................................................................................2
0 Western Wake Regional Wastewater Management Facilities ..............................3
i.4 Purpose and Need...............................................................................................5
Section 1.0 - Population Projections, Design Flows and Wastewater Characteristics ..................7
1.1 Population Projections.........................................................................................7
1.2 Current Population...............................................................................................7
1.3 Existing Land Uses............................................................................................14
1.4 Flow Projections................................................................................................17
1.6 Influent Wastewater Characteristics...................................................................19
1.7 Existing Wastewater Treatment Facility.............................................................19
1.7.1 Treatment Process Overview.................................................................19
1.7.2 Biosolids Management...........................................................................21
1.7.3 Reclaimed Water Production..................................................................22
1.7.4 Treatment Performance..........................................................................23
Section 2.0 - Evaluation of Alternatives.....................................................................................31
2.1 General..............................................................................................................31
2.1.1
Management Option A: "No Action..........................................................31
2.1.2
Management Option B: Optimum Operation of Existing Facilities ..........
32
2.1.3
Management Option C: Harnett County Regional Interconnection .........
32
2.1.4
Management Option D: Treatment at the Western Wake Regional WRF33
2.1.5
Management Option E: UCWRF Expansion and Discharge Relocation..34
2.2 Treatment Process Upgrades............................................................................34
2.2.1
Disc Filters Upgrade...............................................................................35
2.2.2
Deep Bed Denitrification Filters..............................................................36
2.2.3
Supplemental Carbon Feed System.......................................................36
2.2.4
Coagulant Feed System.........................................................................37
Town of Holly Springs
Wastewater Discharge Alternatives Evaluation & Expansion
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4
2.2.5 Biosolids Handling Upgrades..................................................................38
2.2.6 Present Worth Cost Estimate.................................................................39
2.3 Alternative 1: Cape Fear River Discharge.........................................................41
2.3.1 Background............................................................................................41
2.3.2 New Infrastructure..................................................................................42
2.4 Alternative 2: Harris Lake Watershed Discharge...............................................53
2.4.1 Background............................................................................................53
2.4.2 Holly Springs Speculative Limits.............................................................54
2.4.3 New Infrastructure..................................................................................56
2.5 Alternative E-3: Land Application.......................................................................63
2.6 Alternative E-4: Wastewater Reuse....................................................................69
2.7 Alternatives Evaluation & Summary ...................................................................73
Section3.0 - References...........................................................................................................75
APPENDICES
Appendix A.....................................................................................NPDES Permit
Appendix B................................... Correspondence with Division of Water Quality
Appendix C...................................................................... Supplemental Cost Data
Appendix D................................................................... Water Quality Information
LIST OF TABLES
Table..........................................................................................................Page
1-1
Population Trends.................................................................................... 7
1-2
Wastewater Flow Projections.................................................................18
1-3
Influent Wastewater Characteristics.......................................................19
1-4
2008-2010 Average Effluent Data..........................................................27
1-5
Effluent from Expanded UCWRF...........................................................
27
2-1
Chemical Phosphorus Precipitation.......................................................
38
2-2
Cape Fear Discharge Limits...................................................................
42
2-3
Cape Fear River, Present Worth Cost Estimates ...................................
44
2-4
Potential Environmental Impact.............................................................
45
2-5
Harris Lake Watershed Discharge Limits ...............................................
56
2-6
Potential Environmental Impact.............................................................
58
Town of Holly Springs
Wastewater Discharge Alternatives Evaluation & Expansion
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2-7 Lower Utley Creek, Present Worth Cost Estimates ................................ 58
2-8 Land Application, Present Worth Cost Estimates ................................... 65
2-9 Present Worth Cost Summary ................................................................ 73
2-10 Alternatives Summary ............................................................................ 74
LIST OF FIGURES
Figure........................................................................................................
Page*
i-1
Location Map...........................................................................................1
1-1
Planning and Service Area.......................................................................
9
1-2
Capital Improvement Projects................................................................11
1-3
Population Projections...........................................................................13
1-4
Land Use Plan.......................................................................................15
1-5
Flow Projections....................................................................................18
1-6
..............
UCWRF Existing Facilities Site Plan ......................................................
25
1-7
Effluent Flow Trends..............................................................................
28
1-8
Effluent TN & TP Trends........................................................................
29
1-9
Effluent BOD & TSS Trends...................................................................
30
2-1
Alternative E-1: Cape Fear Discharge, Proposed Forcemain Route.......
47
2-2
Alternative E-1: Cape Fear Discharge, Overall Layout ...........................
49
2-3
Alternative E-1: Utley Creek WRF Upgraded Site Plan ..........................
51
2-4
Alternative E-2: Lower Utley Discharge, Proposed Outfall Route ...........
59
2-5
Alternative E-2: Utley Creek WRF Upgraded Site Plan ..........................
61
2-6
Alternative E-3: Land Application, Potential Sites ...................................
67
2-7
Alternative E-4: Reclaimed Water Service Area ....................................
71
*Figures are on or following the designated page.
Town of Holly Springs
Wastewater Discharge Alternatives Evaluation & Expansion
8111520118:12:00 AM Holly Springs EAA _Final 08 10 2011.docx

4
ABBREVIATIONS AND ACRONYMS
201 Plan
201 Facilities Plan Amendment, specifically the Holly Springs
Plan Amendment, prepared in 2006 by Davis -Martin -Powell and
Green Engineering
CG&L
NCDENR DWQ Construction Grants & Loans Section
DWQ
NCDENR Division of Water Quality
EA
Environmental Assessment
EAA
Engineering Alternatives Analysis
EIS, FEIS
Environmental Impact Statement, specifically for the Western
Wake Regional Wastewater Management Facilities
ER, PER
Preliminary Engineering Report
NCDENR
North Carolina Department of Environment and Natural
Resources
NEPA National Environmental Policy Act
NPDES National Pollutant Discharge Elimination System permit program,
specifically permits issued to Holly Springs and Western Wake
Partners
ROD Record of Decision, specifically for the Western Wake Regional
Wastewater Management Facilities
SEPA State Environmental Policy Act
Town
Town of Holly Springs
UCWRF
Utley Creek Water Reclamation Facility
USACE
US Army Corps of Engineers
WRF, WWTP
Water Reclamation Facility (Wastewater Treatment Plant)
Western Wake Partners,
Western Wake Regional Wastewater Management Facilities
Partners
Project Partners, an organization comprised of the Towns of
Cary, Apex, Morrisville, and Holly Springs
WWRWRF
Western Wake Regional Water Reclamation Facility, specifically
referring to the treatment plant and/or site
Town of Holly Springs iv
Wastewater Discharge Alternatives Evaluation & Expansion
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I. PROJECT SUMMARY
i.1 Introduction
Davis -Martin -Powell and Associates was retained by the Town of Holly Springs, NC to prepare an
Engineering Alternatives Analysis (EAA) addressing wastewater treatment system improvements
at the Utley Creek Water Reclamation Facility (UCWRF) to determine the most practicable
discharge system. Preparation of this document was recommended in a February 2010
Speculative Limits letter from the Division of Water Quality in response to the Town's request for
speculative limits for discharge into Harris Lake.
The Town of Holly Springs is a growing community located just south of the Research Triangle
Park (18 miles) and Raleigh -Durham International Airport (23 miles) in western Wake County
(Figure i-1). Holly Springs is bordered on the north by the Extra Territorial Jurisdiction (ETJ) area
of Apex; on the east by the Cary ETJ; on the south by the Fuquay-Varina ETJ; and on the west
by property owned by Progress Energy. There is a large amount of land both southwest and
northwest of Holly Springs' town limits that does not currently lie within any corporate limits.
Figure i-1
Town of Holly Springs
Wastewater Discharge Alternatives Evaluation 8 Expansion
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1.2 Background
The UCWRF serves the Town of Holly Springs and surrounding areas, and is located in Wake
County, North Carolina. The UCWRF is currently permitted to discharge a monthly average
wastewater flow rate of up to 2.4 million gallons per day (mgd) into Utley Creek, a tributary to
Harris Lake, in the Cape Fear River Basin.
The UCWRF was first constructed in the late 1980's with a capacity of 0.25 mgd, and quickly
expanded to 0.5 mgd in 1994. With rapid growth occurring, the Town initiated a 201 Amendment
in 1997 which led to the UCWRF expansion to 1.5 mgd in 1999. During this process DWQ
expressed concerns about impacts on Utley Creek especially Thomas Mill Pond and Harris Lake.
In March 2003 Holly Springs was issued an Utley Creek NPDES permit for 2.4 mgd, with the
condition that the Town would investigate a regional solution for increased flows.
The Town of Holly Springs then contracted with Davis -Martin -Powell and Green Engineering in
2004 to prepare another 201 Facilities Plan Amendment (hereafter referred to as "201 Plan") to
evaluate wastewater treatment options to meet the Town's growing needs. Based on the flow
projections, the Town would need 6.0 mgd (monthly average) treatment capacity for the 2030
planning period. The 201 Plan analyzed the following alternatives to provide wastewater
treatment capacity:
• Land Application
• Expansion of the UCWRF to 2.4 mgd and transfer of 3.6 mgd to Harnett County North
Regional VWIITP at Lillington
• Expansion of the UCWRF to 2.4 mgd and transfer of 3.6 mgd to the Western Wake Regional
WRF for treatment
• Wastewater Reuse System
• Expansion of the UCWRF to 6.0 mgd & convey treated effluent to Cape Fear River with
Western Wake Partners
The 201 Plan was approved in fall 2006 and recommended the expansion of the UCWRF to meet
the Town's wastewater needs through 2025. NCDWQ issued a FONSI for this treatment facility
expansion in February 2007 with language stating that future permits for, or authorizations to
construct, the UCWRF would contain a condition that the Town would convey treated effluent to
Town of Holly Springs 2
Wastewater Discharge Alternatives Evaluation & Expansion
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9
the Cape Fear River with the Western Wake Partners, when that system was available. A copy
of this FONSI is included in Appendix B.
The Town's UCWRF Upgrade and Expansion project proceeded into final design, which was
approved and construction contracts awarded in fall 2007. Construction started in January 2008
and much of the new biological treatment process was placed into service in August 2009. The
overall project was substantially completed in summer 2010.
1.3 Western Wake Regional Wastewater Management Facilities
As early as 2002, six Wake County local governments (including Holly Springs) began working
together to evaluate options for providing long-term wastewater management services for
western Wake County. The Western Wake Partners, comprised of four local governments
(including Apex, Cary, Morrisville and Holly Springs) proceeded with planning for regional
wastewater treatment facilities to serve wastewater needs of western Wake County through the
year 2030. The Western Wake Partners and US Army Corps of Engineers (USACE) developed
an Environmental Impact Statement, which was finalized in 2009, with a Record of Decision
(ROD) issued in July 2010 supporting the implementation of the project.
The Town of Holly Springs has participated in the Western Wake Project as a result of DWQ's
preference for regional cooperation, as stated in the 2007 FONSI for the UCWRF expansion that
"any Authorization to Construct or other necessary permits (orders, etc.) for expansion of the
Utley Creek WWTP will include a condition stating that the treated effluent must be removed from
Utley Creek by the date established in the Certificate authorizing the Towns of Cary, Apex, and
Morrisville and Wake County to Increase Their Transfer of Water from the Haw River basin to the
Neuse River basin under the Provisions of G.S. 143-215.221." As stated in the USACE ROD,
NCDWQ has indicated that as long as the Western Wake Partners are complying with the
requirements of the IBT certificate, the Town of Holly Springs will be deemed to be meeting the
requirements in the FONSI and that no modification is required. (USACE ROD, 2010).
Jointly, the Partners plan to build interceptors, force mains, and pump stations to convey raw
wastewater to a new water reclamation facility, along with discharge facilities to convey the
treated effluent to the Cape Fear River below Buckhorn Dam. Various alternatives and sites were
considered which have included Holly Springs as a participant in only effluent discharge facilities.
Town of Holly Springs
Wastewater Discharge Alternatives Evaluation & Expansion
8115@0118:12:00 AM Holly Springs EAA Final 08 10 2011.docx
3

A
The Holly Springs 201 Plan (2006) recommendations included subsequent construction of an
effluent conveyance system to the Western Wake Regional WRF (WWRWRF). Effluents from
the WWWRF and UCWRF would be combined and then conveyed and discharged into the Cape
Fear River. Speculative limits for this discharge point were issued for both facilities in December
2004, up to 30 mgd from WWRWRF and up to 8 mgd from Holly Springs (maximum month flows).
The WWRWRF project experienced several delays, including the required preparation of an EIS
which began in 2007 and culminated with the USACE ROD. As a result, the original 2011
completion date has been pushed back until at least December 2013. The estimated cost to
Holly Springs increased significantly due to additional work, inflation, and other delays, with the
next phase of construction (effluent pumping, forcemain, and the Partner's effluent conveyance)
now estimated at $39 million. This option would bring the Town's total wastewater infrastructure
improvement costs to $67 million. The overall economic turndown that began in 2008 and is
continuing at this time has forced the Town to further evaluate expenditures on all capital and
infrastructure projects.
Holly Springs was a participant in only the effluent conveyance components of the Western Wake
Partners project, and the design and capacity of the WWRWRF treatment facilities are
independent of Holly Springs' effluent. When Holly Springs withdrew from the partnership, there
was minimal impact to the overall schedule for the remaining partners, as the wastewater
treatment plant site is the first contract to be let and the effluent conveyance construction
beginning approximately 6 months later. Based on preliminary evaluations the effluent pumping
station capacity would be reduced, and the effluent forcemain diameter might be reduced from
60" to 54" which would reduce the construction cost.
There have also been several developments in the planning area and during the planning
process which have opened new potential discharge alternatives for Holly Springs such as:
• Progress Energy Carolinas announced plans to construct additional nuclear power reactors at its
Shearon Harris Facility. To supply adequate cooling water for the new reactors, Harris Lake level
will be expanded, and water must be pumped from the Cape Fear River to supplement the natural
drainage areas. Holly Springs and/or Western Wake Partners effluent discharge into Harris Lake
could in part replace water needed from the Cape Fear River.
• The Western Wake Partners began an evaluation of a discharge into Harris Lake as an alternative
to the costly Cape Fear effluent conveyance system. The Western Wake Partners commissioned
Town of Holly Springs 4
Wastewater Discharge Alternatives Evaluation & Expansion
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0-
water quality monitoring and water quality modeling to determine if both the WWRWRF and
UCWRF effluents could be discharged into Harris Lake without impairing water quality. While this
investigation may have shown Harris Lake was a practicable alternative discharge location; the
additional regulatory approvals required for Cary and Apex IBT certificate could further delay the
project by at least three years and more likely 5 years. The Partners, faced with a June 2014
deadline, determined they could not continue to delay the project, and Harris Lake was determined
to not meet the purpose and need for the Western Wake WRF discharge.
• Since Western Wake Partners evaluation demonstrated that Harris Lake could support the
wastewater discharges, the Town of Holly Springs continued to pursue this option independently.
Additional modeling was conducted to analyze a Holly Springs discharge into the White Oak Arm of
Harris Lake, and presented to NCDENR-DWQ in December 2009 for review. In February2010,
the Town of Holly Springs received speculative limits for a Harris Lake discharge of 6 and 8 mgd.
• The Western Wake Partners' final Cape Fear River NPDES limits were more stringent than the
2005 speculative limits. These more restrictive limits include seasonal (April to October) mass
limits based on permitted flow and a value of 3.5 mg/L for TN and 0.5 mg/L for TP. In addition,
there is a monthly average concentration limit of 5.0 mg/L for TN and 0.75 mg/L for TP, also
applicable from April to October. These changes will significantly affect the level of treatment
required at the UCWRF.
L4 Purpose and Need
The purpose of this Engineering Alternatives Analysis (EAA) is to evaluate the various discharge
alternatives available for the wastewater effluent generated from the Town's expanded treatment
facilities. This is required with any NPDES application in accordance with 15A NCAC
21-1.0105(c)(2) as noted in the speculative limits letters. The 2007 FONSI has justified the project
growth and wastewater flows for Holly Springs and the Western Wake FEIS and ROD were
subsequently justified the 8 mgd.
This EAA is limited to review of viable alternatives to a Cape Fear River discharge, and including
management options of Optimum Operation, Land Application, and Wastewater Reuse.
Connections to other systems (Regional Solutions) were evaluated in the 201 Plan and FEIS and
since the UCWRF plant has been expanded, are revisited in this report. This report was
prepared using the guidelines established in the "Engineering Alternatives Analysis (EAA)
Guidance Document, North Carolina Division of Water Quality/ NPDES (June 23, 2005)" and the
Construction Grants & Loans Division's "Guidance for the Preparation of Engineering Reports"
(April 2005).
Town of Holly Springs
Wastewater Discharge Alternatives Evaluation & Expansion
8115R011 8:12:00 AM Holly Springs EAA Final 08 10 2011.dacn
5

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Town of Holly Springs
Wastewater Discharge Alternatives Evaluation & Expansion
8/15/2011 8:12:00 AM Holly Springs EAA Final OS 10 2011.docx

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Town of Holly Springs 10
Wastewater Discharge Alternatives Evaluation & Expansion
811520118:12.00 AM Holly Springs EAA FlnaIj08 1d 2011.doCX

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Town of Holly Springs 12
Wastewater Discharge Alternatives Evaluation & Expansion
8115)20118:12:00 AM Flolly Sprfngs EAA Final 08 10 2011.docx

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Town of Holly Springs 13
Wastewater Discharge Alternatives Evaluation & Expansion
WlSn011 8:12M M Hdlysptlngs EM_FireW102011.O

1
The Town of Holly Springs has undergone growth rates that are unlike those of the surrounding
Wake County. While Wake County has experienced an annual population growth rate of about
4.3%, Holly Springs experienced a growth rate of 16.8% from 2000 to 2010 (US Census Bureau).
Population projections were developed in 2006 and growth rates were estimated using the higher
Town rate (10.4%, 2004 data) for the first ten years. This growth rate was projected to decline
gradually from 2015 to 2020, then remain equal to the Wake County rate (2.7%, 2004) for the
remainder of the planning period. These higher rate growth projections for the first 10 years are
supported by preliminary development plans already approved by the Town and construction
schedules anticipated by the developers. The growth rate was substantiated by the preliminary
2010 population numbers. The population projections for the Town of Holly Springs are
presented in Figure 1-3.
Town of Holly Springs 8
Wastewater Discharge Alternatives Evaluation & Expansion
8/15/2011 8:12:00 AM Holly Springs EAA Final 08102011.docc

SECTION 1.0 - POPULATION PROJECTIONS, DESIGN FLOWS AND WASTEWATER
CHARACTERISTICS
1.1 Population Projections
In order to evaluate wastewater facilities needs for a 20-year planning period, projections of population
and wastewater flows were prepared. Historical population trends and projections from North Carolina
State Demographics were reviewed. These projections included herein were developed jointly with
Western Wake Partners during 2006 and have been approved in Holly Springs 201 Plan, Western
Wake Partner's FEIS and Engineering Report, and the USACE ROD.
1.2 Current Population
Census data indicates that the Town of Holly Springs was one of North Carolina's most rapidly
growing municipalities between 1990 and 2000. Based on preliminary 2010 Census data,
development continues at a greater rate than Wake County's overall average growth rate, as
shown in Table 1-1.
Table 1-1
Population Trends
908 9,192 912 % 24,661 1
Notes: ` Preliminary Census Data
Based on these population figures, the population of Holly Springs increased approximately
tenfold in a decade, due primarily to new home construction. According to 2000 Census data,
there were 3,316 housing units in Holly Springs, yielding an average household consisting of 2.77
persons. The 2010 Census data has not been fully released at this time.
The Town's existing sewer collection system is shown in Figure 1-1 and their proposed
wastewater service area is depicted in Figure 1-2. Figure 1-2 also identifies major capital
improvement projects (CIP). The other CIP projects shown on this figure are outside the scope of
analysis of this report.
Town of Holly Springs 7
Wastewater Discharge Alternatives Evaluation & Expansion
8115W 1 8.12:00 AM Holly Springs EAA _Final 08_10_2011 Eoc

1.3 Existing Land Uses
The Town currently has zoning ordinances in place which include the following main categories
and corresponding districts.
o Residential: Single Family; Multifamily; High -Density Multifamily
o Commercial/Mixed Use: Neighborhood Village; Local Business; Town Village; Office,
Research, and Development Park; Community Business; General Business
v Industrial: Warehouse/Distribution; Light Industrial; General Industrial
Areas south and west of Holly Springs are experiencing more rapid residential growth.
Commercial and industrial development is expected to dominate the north and west areas of
Town. The proposed Wake County Outer Loop will intersect with the Holly Springs Bypass
immediately north of Town and will likely support more commercial and industrial growth. The
potential growth area west of Town extends to the property owned by Progress Energy. This
area is logical for industrial development.
Figure 1-4 on the following page shows the current Land Use Plan for the Town of Holly Springs
and surrounding areas.
Town of Holly Springs
Wastewater Discharge Alternatives Evaluation & Expansion
8115=11 8.1 ZOO AM Holly Springs EAA Jinal 0810 2011.docx
14

Future
Land Use
Plan
Figure 1-4
F IE 175HIp RD
.�1
11
Torn of Holy Springs 7.!�� �« "il���r���
J�

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Town of Holly Springs 16
Wastewater Discharge Alternatives Evaluation & Expansion
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1.4 Flow Projections
Wastewater flow projections used the Holly Springs' service area to develop the capacity in the
201 Plan Upgrade & Expansion and are presented in the EAA document. These projections were
developed cooperatively for the 201 Plan (2006) and the Western Wake SEPA EIS (CDM, Hazen
and Sawyer, and CH2MHILL, 2005). They were closely coordinated with DWQ NPDES and
CG&L staff to comply with program guidelines in effect at that time. The Town's 2006 FNSI ad
Western Wake ROD were issued based on these projections.
Wastewater flow projections were developed using information and data from water and sewer
billing records, daily monitoring report (DMR) data, and future land use plans. After review and
analysis of water and sewer billing records, DMR data, and future land use plans, the 2030
wastewater flow projection for the Town of Holly Springs was developed using the following
methodology.
o Year 2004 was used as the baseline for flow projections
o The 2004 average daily flow was broken down using billing records into 0.851 mgd
residential, 0.063 mgd Commercial, and 0.007 mgd Industrial
o Population Projections from Section 1.2 were applied
o Maximum month peak factor was determined from DMR data
o Hydraulic peaking factor of 3.1 for effluent conveyance was used based on Western Wake
agreements
The results of the flow projection are presented in Table 1-2 and graphically in Figure 1-5.
Town of Holly Springs 17
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Table 1-2: Wastewater Flow (mgd)
Population
2005
15,090
2010
24,740
20152020
40,570
53,980
2025
62,290
2030
71,870
Residential
0.95
1.63
2.73
3.67
4.25
4.92
Commercial
0.08
0.23
0.47
0.67
0.79
0.94
Industrial
0.11
0.32
0.45
0.57
0.64
0.72
Net Average Daily Flow
1.15
2.17
3.65
4.91
5.68
6.58
Estimated 1/1141
0.32
0.32
0.32
0.32
0.32
0.32
Total Average Daily Flow
1.46
2.49
3.97
5.22
6.00
6.90
Maximum Month Flow
1.76
2.99
4.76
6.27
7.20
8.28
Peak Flow
4.54
7.72
12.31
16.20
18.60
21.38
9,000,
8,000,
7,coo,
6,000,
a
� 5,000,
3
0
u 4,000,
3,000,
2,000,
1,000,
Notes:
(1) 2004 flow plus 70 gpcd for growth population
(2) 2004 flow plus 15 gpcd for growth population
(3) Estimated at 10% of Residenfial & Commercial plus a committed flow of 0.125 mgd
(4) Estimated at 0.32 mgd based on an 1/1 evaluation conducted for Holly Springs's service area and plans
for 1/1 reduction
(5) Average daily flow times 1.2 (Based on DMR data for fiscal year 2002-2003)
(6) Average daily flow times 3.1 (Based on wastewater flow analysis for a portion of Western Wake
service area. This peaking factor is included in the wastewater services interlocal agreement executed
by the Project Partners).
Figure 1-6: Flow Projections
D00
D00
Do0
300
■ Average Annual Flow
• Maximum Month Flow
300
300
)00
)00
)00
0
2000 2005 2010 2015 2020 2025 2030
Town of Holly Springs 18
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1.6 Influent Wastewater Characteristics
UCWRF influent data for the period from January 2008 through December 2010 was reviewed in
order to develop projected wastewater characteristics. This data, summarized in Table 1-4, was
initially presented in the 201 Plan (2006) and served as the basis of design for the facility
Upgrade and Expansion.
Table 1-3
Influent Wastewater Characteristics
Parameter
Flow, mgd
AverageAnnual
1.19
Maximum
Month
1.66
BODE, mg/L
356
508
Total Suspended Solids, mg/L
412
659
Ammonia Nitrogen, mg/L
36
44
Nitrogen (TKN), mg/L
43
53
Total Phosphorus, mg/L
8
8.6
Note: TN & TP limited raw data
1.7 Existing Wastewater Treatment Facility
The UCWRF is located on a 35 acre site just west of the Highway 55 Bypass. The current design
capacity of the plant is 6.0 mgd average flow with a 15.0 mgd process peak flow.
The 6.0 mgd Expansion and Upgrade project was substantially completed during summer 2010
and provides state of the art treatment, multiple process trains, and biological nutrient removal.
An overview of plant processes follows and Figure 1-6 shows a site plan of the UCWRF as
currently configured.
1.7.1 Treatment Process Overview
Preliminary treatment includes an influent flow measurement; dual automatic self cleaning
mechanical bar screens; manually cleaned bypass screen; dual vortex/gravity grit separators; and
Town of Holly Springs 19
Wastewater Discharge Alternatives Evaluation & Expansion
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a grit concentrator. These components are capable of passing a peak flow of 20 mgd. An influent
pump station consisting of six (6) variable speed submersible pumps is capable of delivering peak
influent flows of 20.0 mgd and a maximum RAS flow of 10 mgd. The influent pump station is
designed so that return sludge and the majority of the treatment basins can drain into it by gravity.
Biological treatment is provided using the EIMCO Carrousel"m oxidation ditch process. The Town
installed a single train oxidation ditch with an anoxic zone in 2000 during the 1.5 mgd upgrade
and it had performed well even at high loading conditions. New modifications to the existing train
include the construction of an anaerobic zone, and rating for 1.2 mgd through that train.
In order to obtain the desired capacity, two (2) parallel 2.4 mgd activated sludge oxidation ditches
were constructed including anaerobic and anoxic zones. These units will operate in parallel with
the existing basin, with a new primary flow splitting structure dividing influent flow proportionally
between the three trains.
Dual train second anoxic zone and reaeration zone receive the combined aeration basin effluents
and provide a complete five -stage BNR process to achieve maximum biological nitrogen and
phosphorus reduction. Flow is evenly split between three 90 foot diameter, 16-foot deep,
secondary clarifiers.
A chemical feed system is provided to feed a coagulant to the clarifier inlet to provide for
additional phosphorus removal. This chemical system is designed to use ferric chloride and alum
based coagulants, and the UCWRF Staff has been using sodium aluminate with good results..
Return activated sludge (RAS) flows by gravity to a new RAS/WAS structure and sludge
withdrawal rates are controlled by telescoping valves from each clarifier, metered, and then flows
by gravity to the RAS Screening Building and then to the Influent Pump Station.
Secondary Clarifier effluent is then treated by cloth media disc filters. Four parallel filter units are
provided to handle peak flows with one unit out of service.
Effluent is disinfected with a low pressure -high intensity ultraviolet system. The UV system is
designed with two banks in a single channel, and was designed to meet the NPDES fecal
coliform limits of 200/100ml- with one bank out of service. The channel length can accommodate
Town of Holly Springs 20
Wastewater Discharge Alternatives Evaluation & Expansion
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a third bank to meet the reclaimed water standard of 14/100mL at peak flow rates up to 15 mgd.
The current two bank configuration can meet the reclaimed standard at up to 7 mgd peak flows.
The existing cascade aerator has been utilized for aeration of the effluent during the initial period
when the effluent continues to discharge into Utley Creek. This component will be abandoned
when the ultimate discharge system is constructed.
The facility has two standby diesel generators to provide emergency power and a distributed
SCADA control system.
1.7.2 Biosolids Management
Historically, the UCWRF has relied upon aerobic digestion and land application of liquid sludge
for ultimate disposal (a contracted service with Synagro). In recent years, timely disposal has
become a concern, due to changes in permitted land and weather patterns which limit access to
the fields. Plant Operators have been supplementing the aerobic digestion process with lime
addition to meet Class B requirements, increasing disposal costs about 40%. Private composting
facilities are also utilized to dispose of solids during wet conditions. The Town had been
concerned about the long term viability of the land application program, as finding suitable land is
increasingly difficult due to development and community concerns about land application of
biosolids. Some recently acquired farmland has been up to 50 miles from the plant. Holly
Springs, like many municipalities is developing a comprehensive biosolids management program
with multiple disposal options.
The Expansion & Upgrade project included the Siemens Cannibal® Solids Reduction Process.
This is a relatively new process which utilizes physical and biological treatments to significantly
reduce the volume of sludge which must be disposed.
The Solids Reduction Process operates by continuously screening a portion of the RAS flow to
remove non -biological material. This inert material is estimated to be 25-30% of typical waste
sludge production. The screenings then are compacted and can be disposed of in a municipal
solid waste landfill, similar to headworks screenings and grit. A cyclone separator is also used
remove other inert materials from the RAS. This concentrated material is high in phosphorus and
will be wasted directly to the digester.
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The process also biologically conditions a portion of the RAS using Interchange Tanks equipped
with mixers and diffused aeration. The Interchange Tank has an anoxic environment to further
biologically consume the microorganisms which are normally wasted on a daily basis. Normal
operation of the Interchange Tank is to return conditioned RAS to the aeration basin once each
day, then be refilled with fresh RAS. Construction of the second interchange tank would be
delayed until construction of the effluent conveyance project when the existing cascade aerator is
abandoned. The single 900,000 gallon interchange tank will be adequate until average flow
exceeds 3 mgd.
The process does require periodic solids wasting (or purges), which would be equivalent to a 0.30
sludge yield (pounds of sludge produced per pound of BOD removed). This is much less than the
typical 0.7-1.0 yield anticipated from BNR sludge processes. Purging does not have to occur
daily, but can be scheduled at various frequencies as needed to facilitate sludge disposal
operations. Some plants using this process only purge quarterly or even annually. Decanters will
be provided in all tanks to thicken the sludge.
The existing clarifier was converted into an aerobic digester for treatment of the purged sludge.
Based on the reduced sludge yield, this 0.46 MG basin provides adequate volume for aerobic
digestion to produce a sludge meeting 503 regulations for vector and pathogen reduction. When
needed, lime can also be added to accelerate the stabilization process. At full design capacity,
the digester provides about 20 days holding capacity.
The reduction in sludge volume will result in an immediate savings and extend the useful life of
currently permitted land. McGill Environmental, a private composting facility, has also agreed to
receive waste sludge from the Town when weather conditions prohibit timely land application.
The Town also continues to pursue other sludge disposal alternatives. Potential options include
sending digested liquid sludge to area facilities for thermal drying, dewatering sludge for offsite
composting, and municipal landfill co -disposal.
1.7.3 Reclaimed Water Production
Holly Springs' long-range water supply and wastewater management plans includes a
commitment to promote utilization of reclaimed water. This was initiated in 2000 with the
Town of Holly Springs 22
Wastewater Discharge Alternatives Evaluation & Expansion
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"Wastewater Reuse Master Plan" and since 2007 the Town has completed a reclaimed pumping
system, elevated storage tank, and a significant network of reclaimed distribution mains serving
the western side of Town. Committed reclaimed usage is expected to average over 0.25 mgd
(annual average) with season demands in excess of 0.75 mgd. Reclaimed water came online in
June 2010 and demand from the initial customers has averaged 0.125 mgd.
The reclaimed water quality relies on the effluent filters and UV, and also includes a hypochlorite
system to maintain chlorine residuals in the distribution system to prevent formation of slimes and
possible regrowth of bacteria. The reclaimed water pumps are located downstream of the UV
disinfection and have a firm 1.5 mgd capacity. A 30" diameter pipe segment on the UCWRF site
provides 30 minutes chlorine contact detention prior to reclaimed water utilization. The UCWRF
will utilize reclaimed water for non -potable process water, onsite irrigation, and a bulk water
distribution facility is also located on the site.
See section 2.9 for further discussion of the Reclaimed Water System.
1.7.4 Treatment Performance
Since the 2000 capacity expansion the UCWRF has consistently performed well. The Upgrade &
Expansion project has improved effluent filtration and UV disinfection with new technologies for
more reliable performance and redundancy.
Most components of the expanded process train were placed into initial operation in August 2009
and results are excellent. There was short period during fall 2009 as the new biological process
facilities were being started up and construction of ancillary components were not yet complete,
when nutrient reduction was not being optimized. The Operators immediately begin to review the
situation and optimize the treatment process, and effluent data from 2010 indicates the UCWRF
is achieving the intended results. A summary of effluent data is provided in the following tables
and graphs (Figures 1-7, 1-8, 1-9).
Town of Holly Springs 23
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Town of Holly Springs 24
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NN
ANOXIC/
CLARIFIER 1 REAIR
CLARIFIER CLARIFIER
#2 #3
LIV FILT-ERS
CHEM
SCREEN
BLDG.
SHT
1
E-1
AB 3
AB 2
A13 I
SLUDGE
E
ADMIN.
BLDG.
MAINT.
BLDG.
PS
SLUDGE& RECLAIMED
TRUCK LOADING
IT
il I IPS
n
\-_PROPERTY
LINE
IT BLOWERS -
TOWN OF HOLLY SPRINGS
ENGINEERING ALTERNATIVES ANALYSIS
DISCHARGE ALTERNATIVES EVALUATION
GRAPHIC SCALE
80 40 0 80
FIGURE 1-6
UTLEY CREEK WRIF
EXISTING SITE PLAN

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Town of Holly Springs 26
Wastewater Discharge Alternatives Evaluation & Expansion
8/15/28118:12:Ob AM Holly Springs EAA _Final 08102011.docx

Table 1-4
2008 - 2010 Average Effluent Data
Flow, mgd
2008Parameter
1.00
rr
1.23
r
1.35
BODS, mg/L
1.9
7.2
1.0
TSS, mg/L
3.0
8.4
0.4
Ammonia, mg/I
0.21
1.24
0.38
Fecal Coliform, #/100mL
5
65
< 2
TN, mg/L
11.3
8.9
4.1
TKN, mg/L
6.9
1.9
0.8
NO2-NO3, mg/L
6.0
6.7
3.4
TP, mg/L
3.3
2.8
0.8
2009 during Upgrade & Expansion Construction
. During Jan to April 2009 previous Effluent Filter system experienced mechanical problems
2010 data, also during plant startup
Table 1-5
Effluent from Expanded UCWRF
Flow, mgd
May
rr
1.44
June
2010
1.24
July
2010
1.38
Aug
2010
1.43
Sept
2010
1.31
OctParameter
2010
1.39
2010
1.33
Dec
2010
1.34
BODE, mg/L
2.8
<2
0.1
0.1
<2
<2
<2
2.8
TSS, mg/L
<1
<1
0.2
0.2
<1
1.0
<1
1.0
Ammonia, mgll
<0.5
<0.5
0.0
0.6
<0.5
2.0
<0.5
<0.5
Fecal Coliform, #1100 mL
1
1
1.86
1
<1
<1
<1
<1
TN, mg/L
3.26
2.65
4.06
4.76
3.68
1.98
2.01
2.18
TKN, mg/L
0.67
0.69
0.74
1.13
0.59
0.82
0.67
0.63
NO2-NO3, mg/L
2.65
2.36
3.32
3.70
3.18
1.16
1.34
1.54
TP, mg/L
0.30
1.75
1.51
0.19
0.20
<0.1
<0.1
0.10
Data from UCWRF DMR's
Town of Holly Springs 27
Wastewater Discharge Alternatives Evaluation & Expansion
Wl W0118:12A0 AM Hdly Springs EAA _Fir 08_10_2011.dm

Figure 1-7
Effluent Flow Trends
Flow
3.50
—90 per. Mov. Avg.
I{10N)
3.00
ISO
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2.00
LL
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Town of Holly Springs 28
Wastewater Discharge Alternatives Evaluation & Expansion
8H520118:12:o0AM Holly Springs EAA_riml 08_10_2011. o

Figure 1.8
Effluent TN & TP Trends
20.00
- --
• TP
■ TN
16.00
----- 90 per. Mov. Avg. (TP)
■
---- 90 per. Mov. Avg. (TN)
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Town of Holly Springs 29
Wastewater Discharge Alternatives Evaluation & Expansion
W15f20116:12:00AM HdlyspingsE Fire108_10_2011. a

Figure 1-9
Effluent BOD & TSS trends
10.0
# Boos
• TSS
BA ® -
----•Poty.(BODS)
'.,
____• Poly. (TSSI
0 ooa -
♦
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a
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Town of Holly Springs 30
Wastewater Discharge Alternatives Evaluation & Expansion
B/1620118: 12:00 AM Holly Songs EAA FIne108_10_.2011.d=

SECTION 2.0 - EVALUATION OF ALTERNATIVES
2.1 General
Several Wastewater Management Options were evaluated in preparation of this EAA and the
accompanying EA. These include No Action, Optimum Operation, Regional Solutions, UCWRF
Discharge Relocation and Expansion. These alternatives were evaluated in the 2006 201/EA
and WWRWRF FEIS. Feasible alternatives will be evaluated in the following sections.
2.1.1 Management Option A: "No Action"
The "no action" alternative is not considered feasible because it would not meet immediate and
projected needs for wastewater treatment capacity. The Town has invested nearly $29 million in
the upgrade and expansion of its wastewater treatment facilities over the past 5 years to expand
the treatment capacity to 6 mgd. With no further improvements, the usable capacity would be
limited to the current NPDES discharge of 2.4 mgd, plus any reclaimed water usage.
"No Action" would require future development to be served by private wastewater treatment
facilities or septic tanks. Use of private wastewater treatment facilities is not considered
acceptable because such facilities historically have resulted in poor quality effluent being
discharged to receiving streams. Streams with sufficient assimilative capacity for new wastewater
discharges are also unlikely to be available in the Town's service area. Septic tanks are also not
acceptable on an extensive scale because many of the soils in Wake County have moderate to
severe restrictions for septic tanks due to low soil permeability. In addition, projected
development is expected to be at or near urban densities throughout the portion of the service
area within the Town's growth areas and the adjoining county residential and commercial service
areas.
The lack of available wastewater capacity will also limit industrial development potential which in
turn could have a negative economic impact on the Town's growth and development. Economic
development has recently slowed, but is beginning to rebound. Competition for industry and the
jobs industries provide is likely to be high as municipalities and the State of North Carolina try to
recover from the current economic downturn. A lack of sufficient wastewater capacity could
certainly result in lost economic development opportunities.
Town of Holly Springs 31
Wastewater Discharge Alternatives Evaluation & Expansion
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This alternative will not be considered any further, as it does not meet the purpose and need of
additional wastewater capacity for future growth, nor NCDWQ's desire to remove the discharge
from the headwaters of Utley Creek.
2.1.2 Management Option B: Optimum Operation of Existing Facilities
The existing UCWRF is currently permitted to discharge 2.4 mgd at the current location and was
issued an ATC for 6.0 mgd. This facility is being operated to meet the current 2.4 mgd NPDES
limits. The review of recent plant records (Section 1.7.4) indicates that the UCWRF is currently
operating quite efficiently.
DWQ has indicated it would not allow an expansion in the permitted capacity above 2.4 mgd at
the current discharge location. While the existing facility could treat more wastewater and has
received an ATC for 6 mgd, improvements are needed onsite to meet the speculative limits for
nutrients provided by DWQ for 6 and 8 mgd. Optimal operation would not meet the growth needs
of the town at the current discharge location since higher flow cannot be permitted there. Optimal
operation would not meet the NPDES permit limits at an alternative discharge location. Thus,
optimal operation does not meet the project purpose and need and is not considered further in
this document.
2.1.3 Management Option C: Harnett County Regional Interconnection
Under this Option, the Holly Springs would convey up to 8 mgd of wastewater to the North
Harnett Regional WWTP at Lillington. Continuing to treat and discharge 2.4 mgd at the UCWRF
and transferring 5.6 mgd to Harnett County was considered, however, this does not meet
NCDWQ's desire to remove the discharge from the headwaters of Utley Creek.
The WWRWRF FEIS and ROD evaluated this alternative for Holly Springs. The analysis
completed for that document indicated that Harnett County would need to expand one of its
treatment facilities to accommodate the flow from Holly Springs. In addition, this alternative
would result in extensive impacts from a raw wastewater conveyance facility including stream
crossing and wetland impacts and other risks from increased conveyance of raw wastewater.
Based on the lack of capacity which does not meet the project purpose and need and the higher
Town of Holly Springs 32
Wastewater Discharge Alternatives Evaluation & Expansion
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environmental impacts associated with this alternative, it has been eliminated from further
consideration.
2.1.4 Management Option D: Treatment at the Western Wake Regional WRF
Under this Alternative, Holly Springs would construct a raw wastewater transmission system to
convey 8 mgd to the WWRWRF site. The first phase of the WWRWRF has been designed and
will begin construction in the Fall of 2011.
This alternative was reviewed in the Western Wake FEIS as part of the various regional systems
evaluated and was eliminated based on cost. To achieve the capacity needed, Holly Springs
would have to purchase 8 MGD of capacity in the WWRWRF and a corresponding share in the
WWRWRF effluent conveyance to the Cape Fear River. In 2006 the estimated capital cost of
raw wastewater conveyance and treatment facilities for 3.6 mgd capacity exceeded $63m and the
present worth exceeded $72m (all in 2006 dollars). The WWRWRF, which is about to go to
construction, would likely need to be expanded or components redesigned to accommodate the
additional flow from Holly Springs, resulting in additional expenses. The Western Wake Partners
cannot delay their schedule due to interbasin transfer certificate requirements to return
wastewater to the Cape Fear River and conveying raw wastewater to the proposed WWRWRF
would not meet the purpose and need of that facility. The FEIS and ROD resulted in Holly Springs
continuing to operate its own treatment facilities for flows of 6 and 8 mgd.
Transferring raw wastewater would require the installation of major wastewater pumping station
at Utley Creek, and a flow diversion system. The wastewater pump station and forcemain length
and routing would be similar in scope to the Cape Fear River effluent conveyance alternatives
(Alternative E-1), but would have the additional potential impacts of conveying raw wastewater
rather than treated effluent. Continuing to treat and discharge 2.4 mgd at the UCWRF and
transferring 5.6 mgd to the WWRWRF was considered, however, does not meet NCDWQ's
desire to remove the discharge from the headwaters of Utley Creek.
This option has higher impacts from conveying raw wastewater than treating at the current plant
site, does not meet the WWRWRF purpose and need, and has a higher cost. Thus, it is
eliminated from further detailed study.
Town of Holly Springs 33
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2.1.6 Management Option E: UCWRF Expansion and Discharge Relocation
The UCWRF has a current treatment capacity of 6.0 mgd and is permitted to discharge up to 2.4
mgd of wastewater into Utley Creek. In order to meet the projected wastewater flows of 8.0 mgd
for the 2030 planning period, the Town would upgrade and expand the existing facility as needed
to meet more stringent nutrient limits and relocate the discharge from the current location in the
headwaters of Utley Creek.
Potential alternatives for the discharge of the effluent from the UCWRF evaluated herein include:
• Alternative E-1: Cape Fear River Discharge: This alternative assumes the effluent is
conveyed to the WWRWRF and ultimately discharged into the Cape Fear River. This
alternative was preferred in the 2006 201 Plan to comply with the NCDWQ desire to
remove the discharge from Utley Creek.
• Alternative E-2: Lower Utley Creek Discharge: This alternative assumes the effluent is
conveyed downstream below Greentree Reservoir and is discharged into Utley Creek
upstream of Harris Lake.
• Alternative E-3: Land Application - This alternative assumes the effluent is land applied.
• Alternative E-4: Wastewater Reuse - This alternative assumes the effluent is disposed
of via combinations of landscape irrigation, industrial usage, and bulk reclaimed water.
Details of each of the alternatives are discussed in more detail in the following sections, including
a discussion of the UCWRF process improvements required to upgrade the facility to meet more
stringent nutrient limit requirements now proposed for the Cape Fear River and the Lower Utley
Creek alternatives.
2.2 Treatment Process Upgrades
As previously noted, the UCWRF expansion was designed to meet NPDES effluent limits based
on the Cape Fear River speculative limits, which were proposed at 2 mg/L TP and 6 mg/L TN. To
achieve these goals the facility design included the following process components as described
previously in Section 1.7:
• A 5-stage biological nutrient removal (BNR) process
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e Secondary clarifiers with low surface loading rates
e Cloth media tertiary filters (Kruger DiscFilters)
e Supplemental coagulant chemical feed equipment
The current 5-stage BNR process is capable of achieving effluent total nitrogen levels between
4.0 and 5.0 mg/L. The biological phosphorus uptake process is also generally able to achieve TP
of 1.0 to 2.0 mg/L without any chemical precipitation. Generally accepted practice is to provide
additional treatment processes when lower effluent levels are required by NPDES permit.
During startup the UCWRF has been able to exceed these goals, however current hydraulic
loading is only at 60% of the online units' rated capacity. This high level of performance is based
upon the following operating criteria:
e Suitable ratios of influent BOD5, COD, to nitrogen and phosphorus
e Maintenance of proper levels of activated sludge (MLVSS) in the aeration basins
e Proper management of biosolids wasting
To ensure compliance with the potential effluent limits less than 2 mg/L TP and/or 6 mg/L TN, a
variety of process upgrades could be incorporated into the existing wastewater treatment
process, as discussed in this section. Identification of the needed upgrades will be addressed in
the discussion of each individual discharge alternative (Sections 2.3 to 2.7)
2.2.1 Disc Filters Upgrade
The existing cloth media disc filters are excellent for normal solids reduction, because they are
relatively economical, have a compact foot print, and are easy to maintain. Disc filters also
require a very small volume of backwash water compared to deep bed filters.
Disadvantages with disc filters are the inability to operate in denitrification mode and a limited
ability to chemically remove phosphorus. Consultations with the filter manufacturers have shown
success in meeting a 0.5 mg/L TP limit with the current filter technology and the addition of a
coagulant mixing system immediately upstream of the filter units. This would improve the
efficiency of the chemical dosing system and the ability of the disc filters to remove effluent
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phosphorus. A fifth disc filter unit is also recommended to lower the solids loading rate and
provide capacity for the 8 mgd flow with one unit out of service.
2.2.2 Deep Bed Denitrification Filters
An alternative filter system utilizes deep bed filters for both normal solids reduction and
denitrification of nitrates (NO3-N) to nitrogen gas, which is released to atmosphere. Denitrifying
microorganisms attach to the filter media, which provides the support system for their growth. A
carbon source such as methanol, acetic acid, molasses, etc. is added upstream of the packed -
bed filter and a nitrified influent is filtered through the media. The deep bed filter system is well
suited for denitrification because it provides the necessary hydraulic detention time for the
biological reaction to take place. The filter media is composed of a coarse, hard, predominately
siliceous material (sand). Configuration and operation is very similar to a conventional water
plant filter system.
The additional detention time and media also enhance chemical phosphorus removal, as
compared to the existing disc filter, and some of the coagulant feed upgrades would not be
necessary to meet the lower phosphorus limits.
Preliminary sizing criteria for denitrification filters are based on a loading rate of 2 gpm/SF of filter
area. A total filter area of approximately 2,780 square feet is needed to treat the 8 mgd design
flow. Four filter cells, are recommended so that one cell can be backwashed without excessive
loading on the remaining cells.
Disadvantages to deep bed filters are higher capital cost, larger footprint, relatively high
backwash rate of 6 gpm/SF, plus air scour, large capacity backwash pumps, backwash supply
and waste storage, and filter scour blowers. An upgrade to denitrification filters will require the
removal of the existing cloth media filters.
2.2.3 Supplemental Carbon Feed System
As noted above, a supplemental carbon source is required for the denitrification filters to remove
additional nitrogen. Supplemental carbon can also be feed into the second anoxic zone to
enhance biological denitrification. Methanol is the most common carbon source used at
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wastewater facilities; however cost and availability of alternate source chemicals would be
evaluated during design.
Depending on the biological nitrogen performance and seasonal effluent limits, the amount of
carbon added can be minimized to trim 1-2 mg/L of nitrates, or increased to remove up to 5 mg/L
nitrates. A typical methanol feed system would include an 8,000 gallon storage tank, metering
pumps, and ancillary equipment. An average feed rate would be a 100 gpd design capacity. The
alternative carbon sources have varying chemical and physical properties, so it may become
significantly more expensive to design storage and feed equipment to accommodate all possible
compounds.
2.2.4 Coagulant Feed System
UCWRF currently includes a coagulant feed system as a backup and enhancement for biological
phosphorus removal. The current chemical feed system was designed as polishing step to
remove about 1 mg/L TP to ensure compliance with the anticipated 2 mg/L effluent standard. It is
common practice to provide chemical backup to BNR processes to assist during process upsets,
seasonal changes, etc. Operating initially under the Town's current Utley Creek NPDES permit
(2.4 mgd, equivalent 0.5 mg/L TP), the UCWRF has been able to successfully reduce TP to less
than 0.20 mg/L with aid of chemical precipitation, albeit at high dosages and high chemical cost.
The design was based on using ferric chloride as the coagulant because it is one of the more
aggressive metal salt compounds, however the feed equipment can also be used with several
aluminum compounds, and has initially been operated with sodium aluminate. As illustrated in
Table 2-1 chemical usage could increase 3 to 7 fold to meet lower effluent phosphorus standards.
As described in Disc Filter Upgrades, the filter supplier has recommended a new coagulant
system to enhance effectiveness of the coagulant, additional of a polymer to enhance
phosphorus removal. This would include a concrete mixing basin, vertical mixers; polymer feed
system, additional bulk storage, and a new building to house the chemical feed equipment.
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Table 2-1
Chemical Phosphorus Precipitation
If denitrification filters are determined to be necessary for compliance with lower nitrogen levels,
the disc filters would be removed. A separate coagulation mixing basin would not be needed but
would be incorporated in the deep bed filter inlet channel. Additional coagulant bulk storage and
a new building to house the chemical feed equipment would be needed.
Common to either type of filter technology, compliance with lower phosphorus limits would require
several associated improvements including additional chemical feed lines, an additional
coagulant bulk storage tank and secondary containment structure, and metering pumps .
2.2.5 Biosolids Handling Upgrades
The timely and efficient disposal of biosolids is critical to the overall operation of the treatment
process, and especially so when achieving low nutrient levels. While nitrogen is ultimately
converted to nitrogen gas, phosphorus is only removed from the waste treatment process via
effluent, sludge wasting, or sludge screening/grit.
The UCWRF Cannibal® Biosolids system includes a cyclone separator component to remove
grit from the RAS and research has shown is effective in ultimate phosphorus removal. This grit
stream can be disposed of in a municipal solid waste landfill.
A second 0.95 MG Cannibal® Interchange Tank will need to be constructed. This component
was not included in the initial construct because of conflicts with the current cascade aeration
structure. The Interchange will be needed before the UCWRF reaches 3 mgd of waste flow, and
lower nutrient limits justify its construction to provide operational flexibility.
Town of Holly Springs 38
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Research has also shown the Interchange Tank decant is high in phosphorus, and a Decant
Clarifier can be added to maximize phosphorus removal. The sludge collected will be wasted
directly to the aerobic digester. This component was initially included in the Upgrade and
Expansion design, but construction was delayed to coincide with the second Interchange Tank.
Finally, a Sludge Dewatering Facility is proposed to ensure biosolids can be wasted and disposed
of without the seasonal and wet weather impediments associated with liquid land application. The
Class B sludge cake can be stored onsite, then hauled away for agricultural land application, or
converted into a Class A product by composting or drying. The proposed dewatering facility
would likely include sludge pumps, polymer feed, a single belt filter press, and conveying system
for truck loading. The entire system will be enclosed in a building to minimize odors and protect
equipment.
2.2.6 Present Worth Cost Estimate
A preliminary engineering level cost estimate shows the construction costs and contingencies for
the improvements required for each effluent discharge alternative. The compound amount (F) in
2010 dollars was unchanged from recent (2008) cost estimates. Recent year construction costs
are depressed, however, the conservative approach to account for variable construction market
conditions is to neither inflate nor discount the previous cost estimate methodology. This also
maintains consistency between the Town and Partners previous planning documents.
A construction contingency of 10% and a professional services allowance of 15% has been used
to calculate the total project costs. The Town's anticipated contribution to the Western Wake
Partners is included, and is based on the Western Wake Partners' Engineering Report (Brown &
Caldwell, June 2010) and subsequent data provided by the Town.
The net present value cost estimate was calculated over a 20-year period using a discount rate of
4.875%.
Town of Holly Springs 39
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2.3 Alternative 1: Cape Fear River Discharge
2.3.1 Background
As previously discussed, the Holly Springs 201 Plan (2006) recommended an effluent
conveyance system to the WWRWRF and a Cape Fear River discharge as the most viable
alternative evaluated. The 201 Plan presented the infrastructure upgrades necessary to meet
anticipated permit limits in the Cape Fear River at the current design capacity of 6.0 mgd and
maximum month of 8.0 mgd. This document was referenced in the preparation of the Western
Wake Partners' Environmental Impact Statement (FEIS) & Engineering Report (ER).
The 201 Plan developed a routing for the Utley Creek Effluent forcemain to the Western Wake
Partners proposed WWRWRF, located just north of Highway 1 and west of New Hill - Holleman
Road. This location has been commonly identified as "Site 14" in the Western Wake Partners
planning documents. During the Western Wake Partners EIS process, Site 14, along with
several other possible sites, were evaluated for location of the Partners wastewater treatment
facilities. Issuance of the USCAE ROD has confirmed the selection of Site 14 as the WWRWRF
location. Figure 2-1 shows an overall layout of the proposed Holly Springs effluent conveyance
system from UCWRF to the WWRWRF site. Effluents from the two WRF's would be combined
and then conveyed and discharged into the Cape Fear River near Buckhorn Dam (Figure 2-2).
The current UCWRF treatment process design was based upon the speculative limits issued by
DWQ (December 2005). The final NPDES permit limits issued to the Western Wake Partners
were more stringent than the speculative limits to reduce nutrient loading in the Cape Fear River,
and this section's discussion is based on the final permit limits. Table 2-2 compares the 2004
Cape Fear speculative limits with the final Cape Fear River permit limits issued in January 2011.
This alternative was included in the planning and design documents of the Western Wake
Partners, including the FEIS and USACE ROD (July 2010). Holly Springs has completed
preliminary design of the pipeline and pump station. The issuance of the USACE ROD satisfies
the environmental review requirements for this alternative, and if implemented, USACE/DWQ
404/401 permit application can be submitted, along with an NPDES discharge permit application
for the Cape Fear River.
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Table 2-2
Cape Fear River Discharge Limits
Parameter
Flow, mgd
Cape Fear River
rr• Spec Limits)
Up to 8.0
Cape Fear River
(Final 2011)
Up to 8.0
BODS, mg/L'
5.0 (10.0)
5.0 (10.0)
Total Suspended Solids, mg/L
30.0
30.0
Ammonia Nitrogen, mg/L
1.0 (2.0)
1.0 (2.0)
Total Nitrogen, Ibs/day
4002
Mass basedon
3.5 mg/L
Total Nitrogen, mg/L
----
5.0
Total Phosphorus, lb/day
133 3
Mass basedon
0.5 mg/L
Total Phosphorus, mg/L
----
0.75
Fecal Coliform, #1100 mL
200
200
Dissolved Oxygen, mg/L
6.0
6.0
pH, units
6-9
6-9
'Season limits, summer April -October (winter November -March)
2 Mass limits based on 6 mg/L TN and the permitted flow
3 Mass limits based on 2 mg/L TP and the permitted flow
° Monthly maximum concentrations (April to October)
5 Mass based TN and TP limits (April to October)
2.3.2 New Infrastructure
Currently, the plant discharges treated effluent from the UV disinfection process through a gravity
ouffall and cascade aerator into Utley Creek. To convey flow to the WWRWRF, an effluent pump
station and forcemain are required.
The new effluent pumping structure will be constructed west of the UV facilities. The effluent
structure will include four vertical turbine pumps for effluent transfer and three vertical turbine
reclaimed water supply pumps. The wetwell will be divided to allow the reclaimed water to be
shut down during periods of non-compliance with reclaimed standards. The reclaimed water
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chlorination facilities will also be relocated to the effluent pump station area, and chlorine contact
time will be provided to comply with reclaimed water standards.
All pumps will be provided with variable frequency drives to match flow rates and minimize
electrical operating costs. To meet reliability standards, a new standby diesel generator is
proposed for the effluent pumping system. A new building will be provided adjacent to the new
pump station to house chemical feed equipment, controls, and electrical switchgear.
The effluent forcemain will be a 36" diameter pipeline, with an overall length of 35,400 LF. As
shown in Figure 2-1, the majority of the forcemain route parallels existing public roads; however
temporary and permanent easements will be required in several locations due to stream
crossings, utility conflicts and topographic features.
Compliance with the more stringent phosphorus limits (0.5 to 0.75 mg/L TP) could be achieved by
chemical precipitation; however the lower summer nitrogen limits (less than 3.5 mg/L TN) will
require more extensive process modifications. To ensure compliance with the more restrictive
nutrient limits the following process modifications are recommended, as shown on Figure 2-3 and
described in more detail in Section 2.2:
• Replacement of existing Disc Filters with deep bed Denitrification Filters
• Supplemental Carbon Feed System
• Upgraded Coagulant Feed System
• Biosolids Handling Upgrades including the Decant Clarifier, additional Interchange Tank, and
Sludge Dewatering Facilities
The Western Wake Partners construction contracts would include the forcemain piping on Site 14
(north of Highway 1) and structures to receive the Holly Springs effluent. An effluent pump
station will be constructed by the Western Wake Partners to convey the combined effluents to the
Cape Fear River via about 11.75 miles of 60" diameter forcemain.
Town of Holly Springs 43
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Table 2-3
Alternative E-1: Cape Fear Discharge
Present Worth Cost Estimate
Estimated Costs
Pipe Material
$4,263,695
Valve Costs
$113,400
Air Release Valves
$72,000
Fitting Cost
$135,200
Equipment/Labor Cost
$1,188,000
Erosion Control
$177,000
Seed/Restoration
$122,000
Rock Excavation
$1,770,000
Trenchless Cost
$625,000
Denitrification Filter Upgrades
$4,900,000
Supplemental Carbon & Coagulant Systems
$425,000
Biosolids Facility Upgrades
$2,339,000
Effluent Pump Station
$2,250,000
Subtotal
$189380,300
Contractor OH&P, Bonds, Insurance
$3,037,200 16.5%
Total Construction Estimate
$219417,500
Professional Services
$3,212,600 16.0%
Contingencies
$2,141,800 10.0%
Western Wake Expenses
$12,967,400
Total Capital Cost
$399739,300
Present Worth Pipeline O&M
$675,600
Present Worth Effluent Pumping O&M
$2,069,300
Present Worth Advanced Treatment O&M
$4.602,700
Total Present Worth
$47,086,900
Town of Holly Springs 44
Wastewater Discharge Altematives Evaluation & Expansion
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The proposed work on the existing UCWRF site has no wetlands or stream impacts, however
construction of the effluent forcemain has associated impacts, as summarized in Table 2-4.
Table 2-4
Potential Environmental Impacts
Pipeline Construction to WWRWRF Site
Temporary
Permanent
Perennial Stream Crossings
3 each
None
Intermittent Stream Crossings
3 each
None
Wetland Impacts, acres
0.13
0.03
Town of Holly Springs 45
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Town of Holly Springs 46
Wastewater Discharge Alternatives Evaluation & Expansion
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r
5y �� ®" 5� Legend
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w E Engineering Alternatives Analysis Cape Fear Discharge Alternative E-1
dmp Discharge Alternatives Evaluation Proposed Forcemain Route
S �

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Town of Holly Springs 48
Wastewater Discharge Alternatives Evaluation & Expansion
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iat
W-�A'
Poplar
uckhorn,e
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r�
55
UC RF ife
e
DI
�-- Legend
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55
1 WWRWRF Site
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WWRWRF Effluent
Ha nett � _ _ _
Cnty Bnds (detailed, named)
N 1 inch = 7,500 feet Town of Holly Springs Figure 2-2
w E Engineering Alternatives Analysis Alternative E-1 : Cape Fear Discharge
S �P Discharge Alternatives Evaluation Overall Layout of Effluent System

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Town of Holly Springs 50
Wastewater Discharge Alternatives Evaluation & Expansion
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RECLAIMED
PUMP STA
z
CLARIFIER 1
CLARIFIER
#2
JLATION
FILTERS
f
UV FILTERS
DECANT
CLARIFIER
AB 3
ANOXIC/
REAIR
l_
AD 2
ADMIN.
IrARIFIER BLDG.
#3 AB 1
SLUDGE
PS
I P S SLUDGE I
DEWATERING
L"`-- PROPERTY
LINE
IT BLOWERS_�T_
- - - -SLUDGE& RECLAIMED
TRUCK LOADING
TOWN OF HOLLY SPRINGS
ENGINEERING ALTERNATIVES ANALYSIS
DISCHARGE ALTERNATIVES EVALUATION
GRAPHIC SCALE
80 40 0 80
FIGURE 2-3
UTLEY CREEK WRF
UPGRADED SITE - ALTERNATIVE E-I

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2.4 Alternative E-2: Harris Lake Watershed Discharge
2.4.1 Background
When Holly Springs received their 2.4 mgd discharge permit to discharge in the headwaters of
Utley Creek, DWQ indicated that they would not permit any additional flow at this location and
advised the Town to explore other options. Holly Springs commissioned Tetra Tech to conduct
an analysis of Utley Creek in 2004 as part of the planning for the UCWRF Expansion. The most
significant, potential water quality impairment was identified at that time in Thomas Mill Pond
where chlorophyll -a levels have exceeded the 40 ug1L water quality standard and algal blooms
have been observed. Significant effects in the vicinity of the Greentree Reservoir were not
observed because this impoundment is quite small and several of the flashboards had been
removed. Tetra Tech's report concluded that in general Utley Creek's water quality could
improve with improved level of treatment and increasing flow from the UCWRF but exceedance of
the chlorophyll -a standard might continue in Thomas Mill Pond. While these findings were
positive, the Town did not pursue this option at the time because of DWQ's position on moving
the discharge. Also, at that time, the Town could not afford lengthy delays in the UCWRF
expansion project because of the urgent need for additional capacity in the rapidly developing
service area.
The option of a discharge into Harris Lake was first evaluated in 2008 by the Western Wake
Partners. Preliminary modeling conducted by the Western Wake Partners indicated this was a
viable option, albeit with much lower effluent phosphorus limits than the 2005 Cape Fear River
speculative limits. The scenarios evaluated included both a combined and separated WWRWRF
and UCWRF outfalls into Harris Lake, various effluent flows, and elevated Harris Lake levels. All
indicated that the level of chlorophyll -a in Harris Lake could be maintained within current water
quality standards. The modeling also showed minimal differences in chlorophyll -a between the
combined and separate WWRWRF and UCWRF outfall scenarios. A Final Technical
Memorandum prepared by CH2M Hill (February 2010) summarizes the modeling process.
The Western Wake Partners were forced to abandon the Harris Lake discharge due to
requirements in Cary and Apex's interbasin transfer (IBT) certificate. Modifications to an IBT are
a lengthy process, which would have created excessive delays in the Partners project.
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2.4.2 Holly Springs Speculative Limits
When the Western Wake Partners elected not to pursue this option, the Town of Holly Springs
retained CH2M Hill to continue the monitoring modeling process to further evaluate the UCWRF
discharge into Harris Lake. This analysis was continued through 2009 and summarized in a
Speculative Limits Request and Technical Memorandum (CH2M Hill, December 2009) which is
provided in Appendix B. The point of analysis used is representative of a discharge directly to the
White Oak Creek arm of the lake near New Hill -Holleman Road Bridge. Progress Energy also
indicated support of the UCWRF discharge remaining within the Harris Lake watershed.
After meeting with the DWQ NPDES Unit, this modeling and analysis led to the issuance of the
speculative limits for Harris Lake shown in Table 2-5. The speculative limits granted by DWQ are
more stringent than the original Cape Fear and comparable to the final Cape Fear discharge
limits included in the Final NPDES Permit for Western Wake WRF issued on January 7, 2011.
The limits for total nitrogen (TN) and total phosphorus (TP) are attainable using advanced
treatment technologies.
After receiving speculative limits for Harris Lake, the Town reopened investigations into a
continued discharge into Utley Creek due to the significant cost and potential wetland impacts
associated with a pipeline to the lake. A review of DWQ planning documents indicated that Utley
Creek is not listed as an impaired water body. During 2010 and 2011 the Town, its consultants,
and DWQ's Planning and Permitting Staff revisited the possibility of continuing to discharge
effluent into Utley Creek.
The Town initiated a monitoring program in 2009 to determine the current conditions in Utley
Creek and the two smaller impoundments. The monitoring results showed water quality
improvements since 2004, however there were still elevated chlorophyll -a levels detected in
Thomas Mill Pond. Continued discharge to the headwaters of Utley Creek upstream of Thomas
Mill Pond was eventually ruled out based on the potential for algal blooms and water quality
issues in Thomas Mill Pond.
Two additional discharge locations, Location "A", just below Thomas Mill Pond, and Location "B",
just below Greentree Reservoir, were subsequently evaluated. Results of this effort are
documented in Evaluation of Proposed Utley Creek Discharge which is included as Appendix D.
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This memorandum includes a description of the QUAL2E water quality model of Utley Creek from
Thomas Mill Pond to Harris Lake, results of the monitoring program, and the potential changes in
water quality from 6mgd and 8mgd discharges at Location "A" or location "B".
Greentree Reservoir is not presently impounded, as all flashboards have been removed from the
dam. However, Progress Energy has proposed a pilot wetlands project at Greentree to simulate
the Harris Lake expansion to 240' MSL, which would reinstall some of the flashboards. The
QUAL2E model simulated the Greentree Reservoir being operated in a partially submerged state
as planned by Progress Energy.
This evaluation confirmed that up to an 8 mgd discharge at either location would not adversely
impact water quality and may improve water quality in the lower sections of Utley Creek. A
discharge at Location A, above Greentree Reservoir was eliminated based on uncertainty about
Progress Energy's plans to operate Greentree Reservoir, and concerns about water quality in
Greentree Reservoir when impounded.
A speculative limits request was made for Location B, in the lower reach of Utley Creek,
approximately 0.7 miles above Harris Lake. Location B is preferred over discharge directly into
Harris Lake for the following reasons:
• An outfall into the lake body would require an additional 5,500 LF of effluent pipeline, with
increased capital cost.
• The majority of the pipeline below Greentree Reservoir would be submerged by the
proposed Harris Lake expansion. This is due to the relatively level topography along
Utley Creek approaching the White Oak arm of the lake.
• Additional stream and wetland impacts associated with the lake discharge.
DWQ issued speculative limits for Lower Utley Creek at Location "B" in June 2011 (Appendix B).
The numerical limits were the same as those previously issued for Harris Lake and are
summarized in Table 2-5.
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Table 2-5
Harris Lake Watershed Discharge Limits
Flow, mgd
2.4
6.0 & 8
BOD5, mg/L'
5.0 / 10.0
5.0
Total Suspended Solids, mg/L
30.0
30.0
Ammonia Nitrogen, mg/L'
1.012.0
1.0
Total Nitrogen, Ibs/day 2
120
-----
Total Nitrogen, mg/L
----
5.0
Total Phosphorus, lb/day 3
10.0
-----
Total Phosphorus, mg/L
0.5
0.50
Orthophosphate, mg/L
----
0.27
Fecal Coliform, #/100 mL
200
200
Dissolved Oxygen, mg/L
6.0
7.0
PH, units
6-9
6-9
' Dual limits are summer / winter season
2 Current permit limits are expressed in lb/year and based on 6 mg/L TN
Current permit limits are expressed in lb/year and based on 0.5 mg/L TP
2.4.3 New Infrastructure
This alternative assumes that the effluent from the UCWRF will be conveyed by gravity along
Utley Creek to a point below Greentree Reservoir. A layout of this alternative is presented in
Figure 2-4.
The proposed discharge location (referred to as Location "B") is just below Greentree Reservoir
and approximately 0.7 miles upstream of the current 220' MSL lake level. A discharge structure
could be constructed on the stream bank without extensive impacts within the Utley Creek or the
lake bed. Final design of the outfall pipeline will include several drop manholes to provide re -
aeration and a cascade structure will be designed near the discharge point to aerate the effluent
to meet the 7.0 mg/L DO requirement. The stream elevation at this point is approximately 234'
Town of Holly Springs 56
Wastewater Discharge Alternatives Evaluation & Expansion
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MSL, so if Harris Lake is expanded to the proposed 240' MSL a minimal amount of piping would
be submerged and no additional structures required.
Available GIS data was used to route the pipeline and supplemented with field reviews to
minimize the potential environmental impacts of this alternative. The pipeline has been routed
along existing cleared corridors to the extent possible in an effort to minimize potential wetland,
stream, and other impacts to the environment as well as impacts to individual property owners.
The anticipated nitrogen limits can be achieved with the current 5-stage BNR process, however
additional of supplemental carbon into the 2nd Anoxic stage is desirable to ensure complete
denitrification occurs in the process. Denitrification filters typically would not be needed to meet a
5 mg/L effluent TN. Upgrades to optimize phosphorus removal are needed, especially with the
low 0.25 mg/L orthophosphate limit, and an additional disc filter has been recommended.
The following UCWRF treatment process upgrades are recommended, as described in more
detail in Section 2.2:
• Supplemental Carbon Feed System into Second Anoxic Zone
• Coagulation Basin, upgraded Coagulant Feed System, additional disc filter
• Biosolids Handling Upgrades including the Decant Clarifier for phosphorus wasting, additional
Interchange Tanks, and Sludge Dewatering Facilities
Ancillary improvements at the UCWRF will be required since an effluent pump station will not be
constructed. These include an effluent flow metering structure and reclaimed water pumping
station to be constructed to the west of the current UV disinfection facility. Demolition of the
existing structures are necessary to allow room for the new decant clarifier and interchange tank.
These UCWRF improvements are shown on Figure 2-5. The proposed work on the existing
UCWRF site has no wetlands or stream impacts; however construction of the effluent ouffall has
associated impacts, as summarized in Table 2-6.
The estimated costs of this alternative are summarized in Table 2-7, as well as the net present
worth of this alternative. The Town's share of the Western Wake Partners expenses has been
reduced by eliminating participation in effluent conveyance construction.
Town of Holly Springs 57
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Table 2-6
Potential Environmental Impacts
Outfall Pipeline Construction
Temporary
Permanent
Pipeline Length, feet
11,700
11,700
Perennial Stream Crossings
4 each
None
Intermittent Stream crossings
3 each
None
Wetland Impacts
0.10
0.06
Table 2-7
Alternative E-2: Lower Utley Creek Discharge
Present Worth Cost Estimate
Estimated Costs
Pipe Material
$2,255,715
Manhole Materials
$276,000
Equipment/Labor Cost
$480,000
Erosion Control
$140,400
Seed/Restoration
$60,000
Rock Excavation
$1,170,000
Trenchless Cost
$375,000
Phosphorus Removal Upgrades
$409,000
Supplemental Carbon & Coagulant Systems
$425,000
DiscFilter Upgrades
$693,000
Cascade Aerator
$343,000
Relocated Reclaimed Water Pump Station
$468,000
Biosolids Facility Upgrades
$2,339,000
Subtotal
$9,434,000
Contractor OH&P, Bonds, Insurance
$1,558,000 16.5%
Total Construction Estimate
$10,992,000
Professional Services
$1,648.800 15.0%
Contingencies
$1,099,200 10.0%
Western Wake Expenses
$837,000
Total Capital Cost
$14,677,000
Present Worth Pipeline O&M
$223,300
Present Worth Effluent Pumping O&M
WA
Present Worth Advanced Treatment O&M
$5,001,100
Total Present Worth
$19,801,400
Western Wake Expenses, estimate from Town of Holly Springs.
Town of Holly Springs 58
Wastewater Discharge Alternatives Evaluation & Expansion
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11
s., 6
HARRIS LAKE
I
PROPOSED
48" "OUTFALL\
r
r f{l
7GRIEENTRE;ESERVOIR
PROP' DISCHARGE
LOCATION
1 l
i
MILL
w
K
O
-Y
OILY SPRINGS NEW HIL Legend
Lower Utley Creek Outfall
Harris Lake (Future 240')
w
WRF-structures o
x
S MILL UCWRF Site O
0
WWFWRF Site
w ; Wake_MajorRoads_2010_03
g TRAD ON
aWake_ Streets_2010_03 HILL
JLakes, Ponds RIDGE
Streams
Incorporated Areas
EXISTING
UCWRF \ PE_HAR_Wetlands
g
Ji.
Fff
a
14U
0
N 1inch =1,500feet Town of Holly Springs Figure 2-4
W E �;: Engineering Alternatives Analysis Alternative E-2: Lower Utley Creek Discharge
Discharge Alternatives Evaluation Proposed Outfall Route
S =

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0
N
N
CLARIFIER 1 ANOXIC/REAIR
JIL�
b- I _ ADMIN.
CLARIFIE CLARIFIER BLDG.
#2 #3
EFFLUENT & I NEW _ _
RECLAIMED I DENITE
PUMP STA I FILTER SH
1
BLIP S.
UV FILTERS'
DECANT
CLARIFIER IPS SLUDGE
DEWATERIN�
.ice s I
PROPERTY
f LINE
UTLEY CREEK - J
IT BLOWERS
-- _SLUDGE& RECLAIMED
TRUCK LOADING '
TOWN OF HOLLY SPRINGS
ENGINEERING ALTERNATIVES ANALYSIS
DISCHARGE ALTERNATIVES EVALUATION
GRAPHIC SCALE
80 40 0 80
FIGURE 2-5
UTLEY CREEK WRF
UPGRADED SITE - ALTERNATIVE E-2

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2.5 Alternative E-3: Land Application
The use of spray irrigation as an alternative to surface water discharge was analyzed as part of
the Town's long-range study in 1996 and the 201 Plan (2006). The quantity of well -drained soils
in the Holly Springs area is highly limited. Areas with Appling, Cecil, and Norfolk soils are most
desirable, but they are primarily found in areas of Town and the ETJ that are already developed,
or are now being developed. Mayoden and Pinkston soils are fairly desirable for irrigation, and
are present just west of Holly Springs, on Progress Energy's "Harris Gamelands" property.
The Harris Gamelands site has approximately 350 acres of suitable soil conditions. At
conservative loading rates of 0.5 inches per week, this site could only support about 0.69 mgd of
wastewater. Other large tracts of land that could be irrigated have poor drainage qualities and are
too steep for land irrigation systems. See Figure 2-6.
The land application alternative involves the construction of treated effluent storage and land
application (irrigation) facilities. These facilities would be located at a dedicated land application
site. The land application site would require a cover crop to take up the moisture and nutrients
from the wastewater effluent.
The land area required for land application of a wastewater volume equal to the 8.0 mgd capacity
is estimated at approximately 3,100 acres. This is based on a conservative land application rate
of 0.67 inches per week through a spray irrigation system. The spray fields would be cultivated
with suitable annual crops, timber, etc.
Additional land would be required for buffers from property lines, residences, water, and drainage
features as well as for 30 day effluent storage (240 million gallons) lagoons. The additional land
area required for ancillary facilities and buffers is estimated to be 500 acres (15%), for a total area
of approximately 3,600 acres. Table 2-8 presents a cost summary of the land application
alternative.
Since no specific sites have been identified, the costs of pumping and transmission infrastructure
required to convey the flow from the UCRWF to the land application site cannot be defined. The
preliminary cost estimates include an effluent pumping station similar to Alternative E-1, but does
not include a force main cost. For this same reason environmental impacts were not estimated.
Town of Holly Springs 63
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Purchasing the necessary land may also prove problematic as the potential areas are in Wake
County and NC GS 153A-15 would prohibit the Town from purchasing the land without the
consent of the Wake County Commissioners. The high cost of the land required, plus the
additional facilities for treatment and effluent transportation make this alternative more costly than
any other alternatives. The conclusions of previous studies are still valid. The high cost of land,
limited suitability of area soils, and cost of treatment and application facilities make this option
non -cost efficient. For these reasons, land application is not considered a feasible alternative.
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Table 2-8
Alternative E-3: Land Application
Present Worth Cost Estimate
Estimated Costs
30 day Holding Tanks/Lagoons
$7,345,000
Effluent Pump Station
$2,250,000
Electrical Work
$200,000
Spray Irrigation Piping
$16,938,347
Fence
$903,000
Access Roads
$350,000
Erosion Control and Seeding
$4,705,096
Spray Field Maintenance & Operations
Equipment
$85,000
Nutrient Removal Upgrades
$0
Cascade Aerator
$0
Biosolids Facility Upgrades
$2,339,000
Subtotal
$359115,000
Contractor OH&P, Bonds, Insurance
$5,801,000
Total Construction Estimate
$40,916,000
Professional Services
$6,137,400
Contingencies
$4,091,600
Land Acquisition
$36,100,000
Western Wake Expenses
$837,000
Total Capital Cost
$88,082,000
Present Worth Pipeline O&M
NIA
Present Worth Effluent Pumping O&M
$2,069,300
Present Worth Advanced Treatment O&M
NIA
Present Worth Land Application O&M
$3,148,800
Total Present Worth
$93,300,100
16.5% 1
15.0%
10.0%
Does not include force mains to convey effluent from the UCWRF to unknown land application sites.
Western Wake Expenses, estimate from Town of Holly Springs.
Town of Holly Springs 65
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OL SPRINaS�NI 1 N'4y
LLY SPRINGS g �' Legend
WRF- IWdures THOMAS MILL i� HarrlsG-1.,.ds
y`� ----- UCWRFS1W '
/ 0 WWFWRF SR.
W
Streams
/ K T�D/%/Oj� lakes, POMs
i
a
Harris lake (Future
Wake Streets 2010 03
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NTINE
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—1 de
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F
H 1 inch = 1,000 feet Town of Holly Springs Figure 2-6
WE dm Engineering Alternatives Analaysis Alternative E-3: Land Application
S EP Discharge Alternatives Evaluation Potential Sites

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2.6 Alternative E-4: Wastewater Reuse
The Town of Holly Springs has implemented a new Reclaimed Water System, which was just
placed into service in the summer 2010. Reuse of treated effluent is an option that could relieve
the quantity of wastewater discharged into the waters of the states via NPDES discharge. An
overview of the current service area is shown in Figure 2-7.
Water reuse systems in the central region of North Carolina are predominately landscape
irrigation -based systems that experience high demands during the hot, dry summer season, and
little to no demands during the cool, wet winter season. To effectively reduce the volume of
NPDES discharge capacity on a year-round basis, commercial and industrial users are a
necessity.
The Town of Holly Springs Reclaimed Water System has been planned as a component of larger
planning initiatives of the Town, including the Comprehensive Land Use Plan and the Secondary
& Cumulative Impacts Master Mitigation Plan (SCIMMP). Both of these documents comprise a
comprehensive planning program aimed at allowing the Town to develop in a manner that
minimizes adverse environmental impacts and preserves the valuable environmental resources in
the Holly Springs area. Wastewater reuse is only one part of the overall program, which also
encompasses transportation planning, erosion and sediment control, storm water management,
potable water and wastewater planning, and open space and recreation planning.
A Wastewater Reuse Master Plan was developed in 2000 to guide the Town in the phased
construction of its reuse system. The specific objectives of the Master Plan are to support the
overall objectives of the SCIMMP by minimizing actual wastewater discharges, conserving
potable water supplies, and protecting potable water quality. Holly Springs' approach to
wastewater reuse is a part of a broadly focused, balanced planning process intended to conserve
high quality water supply sources as well as to minimize the volume of wastewater discharged.
Holly Springs, while predominately residential, is building an industrial and commercial customer
base, and actively promotes reclaimed water for process and cooling needs as much as practical.
Industrial and cooling water users are less subject to seasonal peaks than irrigation, and
therefore allow for consistent year-round utilization of reclaimed water. These type users will
Town of Holly Springs 69
Wastewater Discharge Alternatives Evaluation & Expansion
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Y
accomplish two goals, the minimization of wastewater discharges and conservation of potable
water supply.
The initial Holly Springs Reclaimed Water System was constructed from 2006-2010. This initial
phase, including supply pumps, chlorination, distribution piping and an elevated tank, provides
reclaimed water to a service area north of the UCWRF which includes the Holly Springs Business
Park, Twelve Oaks golf course, and Twelve Oaks residential development. Bulk Water will also
be available at the UCWRF site for contractors, landscapers, and other approved users. Initial
estimates for reclaimed water use have ranged from 90,000 gpd during winter months to 750,000
gpd on peak summer time days.
The Town plans to implement additional phases of Reclaimed Water distribution as economic and
customer demands allow. All of the newer and proposed subdivisions within the Reclaimed
Water Service Area are planned to include "purple pipe" distribution systems for future use. Holly
Springs is committed to maximizing the reclaimed water usage to the extent possible.
Since the Holly Springs' primary reclaimed water customer base at this time consists of
residential seasonal users and irrigation systems, implementation of the Reclaimed Water
System will not significantly reduce the NPDES discharge volume. Discharge of the full treated
volume may be required during winter months; however, with the seasonal demand peaking in
summer, the effluent loading on the receiving waters will be significantly reduced during the more
sensitive warm weather months. Still, as a full alternative, wastewater reuse is not considered a
viable alternative at this time and no cost estimate can be provided.
Town of Holly Springs
Wastewater Discharge Alternatives Evaluation & Expansion
811520118:12:00 AM Holly Springs EAA Final 08102011.docx
70

44
0
l'I IE TOWN OF
Holly
Springs
NORTH C,AROLINA
Reclaimed Water Map
Base Man Data
ujJ a
T—Nea
•a¢ao�Mee wr.,
1[I
nem
ReuseP mO S,a'wn
•
ReW mN Tam
------
6n Reuse Wa�e�rc
���
1)n Reuu WAeRro
]M R¢uu Water ne
•••........
Unknown $¢¢Reuse
Figure 2-7
Reclaimed Water System

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Town of Holly Springs 72
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2.7 Alternatives Evaluation & Summary
Potential wastewater management alternatives were developed and evaluated in the preceding
pages. After initial review, Alternative E-4: Wastewater Reuse, and Alternative E-5: "No Action",
were determined not feasible as they are not capable of meeting the project purpose and need.
The present worth costs for the alternatives are summarized in Table 2-9 below.
A review of the present worth costs shows Alternative E-2: Lower Utley Creek Discharge, to be
the most economically and environmentally attractive and feasible alternative. .
Table 2-9
Present Worth Cost Summary
Notes:
1) Present worth analysis based on 20 year planning period with a discount rate of 4.875%
2) NTF -Not Technically Feasible for this Project
3) Western Wake Expenses are based upon Partners Cost Estimates provided by the Town, and are
included in the Capital Cost shown
4) Land costs for Alternative E-3 are assumed to be 50% salvage value
The preferred Alternative for the Town's wastewater discharge is Alternative E-2: Lower Utley
Creek Discharge. Table 2-10 summarizes the project elements and impacts of the feasible
alternatives evaluated in this report and the accompanying Environmental Assessment.
Town of Holly Springs 73
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Table 2-12
Alternatives Summary
Preferred
Alternative
Alt. E-1
Alt. E-3
Alt. E-2 Lower Utley
Cape Fear River
Discharge
Land Application
Creek Discharge
Net Present
$19.8 M
$ 47.1 M
$93.3 M
Worth
Phosphorus
0.50 TP
0.75 winter
N/A
Limits, mg/L
0.27 OrthoP
0.50 summer
Nitrogen
5.0
5.0 winter
N/A
Limits, mg/L
3.5 summer
Denitrification
No
Yes
No
Filters
Phosphorus
Removal
Yes
No
No
Upgrade
supplemental
Coagulation &
Yes
Yes
Yes
Carbon Feed
Biosolids
Yes
Yes
Yes
Upgrades
Effluent Pump
Station
No
Yes
Yes
Effluent Line
11,700
35,400
TBD
(LF)
Gravity
Forcemain
Wetland
0.10 temp
0.13 temp
TBD
Impacts (ac)
0.06 perm
0.03 perm
Stream Impacts
3 intermittent
3 intermittent
TBD
4 perennial
3 perennial
Town of Holly Springs 74
Wastewater Discharge Alternatives Evaluation & Expansion
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SECTION 3.0 - REFERENCES
1. Town of Holly Springs, Utley Creek Wastewater Treatment Plant. 201 Facilities Plan Amendment.
Davis -Martin -Powell & Associates & Green Engineering . August 2006.
2. Town of Holly Springs, Reclaimed Water System. Engineering Report. Davis -Martin -Powell &
Associates. April 2007.
Final Environmental Impact Statement for the Western Wake Regional Wastewater Management
Facilities. CDM and CH2M HILL. 2010. http://www.saw.usace.army.mil/Wetlands/Proiects/WW-
WTP/index.html
3. Record of Decision, Western Wake Regional Wastewater Management Facilities. U.S. Army
Corps of Engineers. July 2010. http://www.saw.usace.army.miUWetiands/Proiects/WW-
WTP/index.html
4. Town of Holly Springs, Secondary & Cumulative Impact Master Mitigation Plant. CH2M HILL.
Updated bi-annually by TOHS. http://www.hollvspdnosnc.us/dept/engineering/scimp/index.htm
5. Modeling Analysis of the Holly Springs WWTP Nutrient and BOD Discharge Impact on the Utley
Creek Watershed. Tetra Tech, Inc., July 2004.
6. Technical Memorandum, Evaluation of Potential Holly Springs Discharge Scenarios. CH2M HILL.
December 2009.
7. Harris Lake Discharge Evaluation Technical Memorandums (Final Compilation). CH2M HILL.
February 2010.
6. Western Wake Partners, Western Wake Regional Wastewater Management Facilities.
Engineering Report. Brown & Caldwell. June 2010.
http://www.westernwakepartners.com/documents.htmi
9. Technical Memorandum, Evaluation of Proposed Utley Creek Discharge. CH2M HILL. June
2011.
Town of Holly Springs 75
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