NC0090247_More Information (Received)_20240415

Smith
April 151h, 2024
Mr. John Hennessy
North Carolina Department of Environmental Quality (NC DEQ)
Division of Water Resources
NPDES Permitting Program
512 N. Salisbury Street
Raleigh, NC 27604
Subject: Request for Additional Information
Draft NPDES Permit NC0090247
Clear Creek Wastewater Treatment Plant
Henderson County
Dear Mr. Hennessy:
This letter is being provided in response to the letter issued by the Division on March 19th, 2024 to
request additional information for the subject Draft NPDES Permit NC0090247 — Clear Creek
Wastewater Treatment Plant (WWTP). Henderson County has reviewed the request and elected to
provide a revised Present Value Cost Analysis from the Engineering Alternatives Analysis for the Direct
Discharge option to base effluent limits of BODS = 10.0 mg/L and NH3 as N = 2.0 mg/L. It should be
noted that the Clear Creek WWTP was already being designed for full nitrification as presented in the
subject permit's Engineering Alternatives Analysis due to the initially prescribed NH3 as N speculative
limit for the future flow conditions of 0.5 MGD. In order to meet the effluent limits noted in the above -
mentioned letter, the only unit process that would need to be added to the Clear Creek WWTP would be
tertiary filtration. No other unit process presented in the Engineering Alternatives Analysis would need
to be altered.
Attached to this letter is an updated Net Present Value Cost Analysis for the Connection to the City of
Hendersonville WWTP alternative and the Direct Surface Discharge alternative. Also attached, is the
capital cost buildup for both alternatives for reference. Below are the key assumptions that were made
in developing the updated Capital Costs and Net Present Value Cost Analyses. It should be noted that
the Capital Costs and Net Present Value Cost Analyses presented in the Engineering Alternatives Analysis
dated April 2023 were developed in 2022, for which reason the updated estimates are escalated over
two years in order to provide estimates in current 2024 dollars.
Connection to the City of Hendersonville WWTP Capital Cost Estimate Assumptions
1) All unit prices that were presented to the Division in the document titled EAA Capital Costs
Estimates (CDM Smith, 2022) in August 2023 were escalated 4% annually over two years.
Direct Surface Discharge Capital Cost Estimate Assumptions
1) Steel Tank Package WWTP item cost estimate was revised based on the updated cost proposals
provided by the package WWTP vendors in April 2024.
4600 Park Road Suite 240, Charlotte, NC 28209 1 tel: [phone]

Smith
Mr. Hennessy
April 151h, 2024
Page 2
2) Tertiary Disc Filter item cost estimate was developed based on cost proposals provided by disc
filter vendors in April 2024. Two disc filters units with associated backwashing pumping
equipment and instrumentation are being proposed to be operated in a duty/standby
configuration. Each disc filter unit is sized to treat the average day max month flow and
hydraulically pass the peak hourly flow.
3) Influent Pump Station item cost estimate that was presented to the Division in the document
titled EAA Capital Cost Estimates (CDM Smith, 2022) in August 2023 was escalated 4% annually
over two years.
4) Unit prices for Site Grading, Excavation and handling of spoils, Backfill, stone, compaction, and
Package Plant Concrete Slab that were presented to the Division in the document titled EAA
Capital Cost Estimates (CDM Smith, 2022) in August 2023 were escalated 4% annually over two
years. Quantities for these unit prices were increased to add the tertiary disc filter units.
Connection to the City of Hendersonville WWTP Net Present Value Cost Analysis Assumptions
1) Capital cost based on revised capital cost buildup for this alternative as described above. As
presented in the Engineering Alternatives Analysis, no capital cost assumed for infrastructure
improvements at the City of Hendersonville WWTP.
2) Recurring costs for 3rd Party O&M Contract and Maintenance and Repairs escalated two years at
4% annually. Recurring costs for Rate Surcharge remain unchanged.
3) Discount rate updated to 2.75% based on latest guidance from the Federal Register for discount
rates for water resource planning projects.
Direct Surface Water Discharge Net Present Value Cost Analysis Assumptions
1) Capital cost based on revised capital cost buildup for this alternative.
2) Recurring costs for 3rd Party O&M Contract and Chemicals and Utilities escalated two years at
4% annually. Recurring costs for Maintenance and Repair updated based on updated equipment
costs for the package WWTP and disc filter units.
3) Discount rate updated to 2.75% based on latest guidance from the Federal Register for discount
rates for water resource planning projects.
In conclusion, the updated Net Present Value Cost Analysis for the Connection to the City of
Hendersonville WWTP results in a 20-year lifecycle cost of $13.11M. The updated Net Present Value Cost
Analysis for the Direct Surface Water Discharge results in a 20-year lifecycle cost of $11.81M. Based on
these results, the recommendation of the Engineering Alternatives Analysis remains unchanged and
suggests that the Direct Surface Water Discharge alternative is the most financially viable option for
Henderson County.
4600 Park Road Suite 240, Charlotte, NC 28209 1 tel: [phone]

Smith
Mr. Hennessy
April 151h, 2024
Page 3
If you have any questions or require anything further, please do not hesitate to contact me at (704) 342-
4546 or at [e-mail].
Sincerely,
Jonat"I han Lapsley, P.E., P
Vice President
CDM Smith Inc.
cc: Marcus Jones, P.E., Henderson County
William Buie, P.E., WGLA Engineering, PLLC
Anish Luthra, P.E., PIMP, CDM Smith Inc.
Siying Chen, NC DEQ Division of Water Resources
Julie Gryzb, NC DEQ Division of Water Resources
Mike Montebello, NC DEQ Division of Water Resources
4600 Park Road Suite 240, Charlotte, NC 28209 1 tel: [phone]

EAA Capital Cost Buildup (Updated April 2024)
Connection to Hendersonville WWTP
Proposed Clear Creek WWTP
Item
Quantity Unit
Unit Price
Price
Item
Quantity Unit
Unit Price
Price
Clearing & Grubbing
10 ac
$
11,816
$
118,165
Steel Tank Package WWTP
1 LS
$
3,555,240
$
3,555,240
Erosion Control
1 LS
$
162,240
$
162,240
Tertiary Disc Filters
1 LS
$
777,775
$
777,775
24" Gravity Sewer
11000 LF
$
359
$
3,950,003
Influent Pump Station
1 LS
$
600,288
$
600,288
Dewatering
1 LS
$
270,400
$
270,400
Site Grading
331 cu yd
$
55.70
$
18,426
48" Steel Encasement Bored
80 LF
$
3,245
$
259,584
Excavation and handling of spoils
2924 cu yd
$
10.82
$
31,622
5' Diameter Manholes
40 Ea
$
8,653
$
346,112
Backfill, stone, compaction
1711 cu yd
$
118.98
$
203,612
Washed Stone Bedding
25000 TN
$
38
$
946,400
Package Plant Concrete Slab
428 cu yd
$
1,315.23
$
563,111
Sewer Services
1 LS
$
54,080
$
54,080
Incidental Stone
4000 TN
$
38
$
151,424
Stream Crossings
2 Ea
$
21,632
$
43,264
Seeding and Stabilization
10 ac
$
5,408
$
54,080
Equipment, Labor, Taxes Subtotal
$
6,355, 752
$
5,750,074
Mobilization (3%)
$
190,673
$
172,502
General Conditions (7.5%)
$
476,681
$
431,256
Bonds, Insurance, and Permitting (5%)
$
317,788
$
287,504
Contractor's OH&P (10%)
$
635,575
$
575,007
Project Subtotal
$
7,976,469
$
7,216,343
Contingency (15%)
$
1,196,470
$
1,082,451
Engineering (18%)
$
1,435,764
$
1,298,942
Permitting Costs
$
150,000
$
40,000
Easement Acquisition Cost
$
190,000
$
75,000
Total
$
10,948,800
$
9,712,800

Henderson County Wastewater Treatment Facility
Engineering Alternatives Analysis - Appendix C (April 2024 Update)
Connect to a Sewer Collection System
1. Capital Costs
A. Gravity Connection to City of Hendersonville Sewer
See CDM Smith Gravity Sewer for breakdown of capital costs.
Capital Cost:j $ 10,948,800.00
B. Upgrades to Hendersonville Wastewater Treatment Plant
No anticipated cost for any upgrades to the Hendersonville Wastewater Treatment Plant are expected. See Appendix B.
Capital Cost: 1 $ -
C. Total Capital Cost
Total Capital Cost: 1 $ 10,948,800.00
2. Recurring Costs
A. Operations and Maintenance Costs
O&M Costs have been calculated on a yearly basis for maintenance of the gravity pipeline.
Cost per Year
$ 33,746
$ 21,632
$ 80,000
$ 135,378
$ 135,378
3rd Party O&M Contract:
Chemicals and Utilities:
Maintenance and Repairs:
Rate Surcharge:
Subtotal:
Contingency:
Yearly O&M Cost:
B. Treatment Costs
The City of Hendersonville charges sewer customers based on meter size, customer type, and other various factors. Due to uncertainty
regarding individual account meters and type of customer, these costs are not evaluated herein. The County users would be required to pay
the "Outside City Limits" rates, which can be set up to 60% above the "Inside City Limits" rate.
C. Total Recurring Cost
Total Recurring Cost: 1 $ 135,400.00
3. Present Value Cost Analysis (PVCA):
-
L
J
Life of facility, n:
20.00
Discount rate, r:
2.750%
Capital Cost, Co:
$10,948,800
Recurring cost, C:
$135,400
P/A = ((1+r)^n - 1)/(r(1+r)^n)
15.23
PV = $10948800 + $135400*((1+2.250%)20 - 1)/(2.250%(1+2.250%)20)
PV = $10948800'15.23
= $13,100,000
4. Notes
1. Discount Rate - https://www.federalregister.gov/documents/2023/11/16/2023-25310/change-in-discount-rate-for-water-resources-planning

Henderson County Wastewater Treatment Facility
Engineering Alternatives Analysis - Appendix F (April 2024 Update)
Surface Water Discharge
1. Capital Costs
A. New Wastewater Treatment Facility
Plant Site and Equipment':
200,000 GPD WWTF: $ 8,695,766
Influent Pump Station: $ 1,016,971
Total Capital Cost: $ 9,712,800
2. Recurring Costs
A. Yearly Recurring Costs for Treatment Facility
3rd Party O&M Contract:
$ 50,619
Chemicals and Utilities:
$
25,958
Maintenance and Repairl
$
58,248
Rate Surcharge:
$
-
Subtotal:
$ 134,826
Contingency:
$
Total Recurring Cost: $ 134,900
3. Present Value Cost Analysis (PVCA):
Life of facility, n:
20.00
Discount rate 2, r:
2.750%
Capital Cost, Co:
$9,712,800
Recurring cost, C:
$134,900
P/A = ((1+r)An - 1)/(r(1+r)An)
15.23
PV = $9712800 + $134900`((1+2.250%)20 - 1)/(2.250%(1+2.250%)20)
PV = $9712800 + $134900*15.96
$11,800,000
4. Notes
1. Discount Rate https://www.federalregister.gov/documents/2023/11/16/2023-25310/change-in-discount-rate-for-water-resources-planning