NC0023981_Fact Sheet_20240528

Fact Sheet
NPDES Permit No. NCO023736
Permit Writer/Email Contact: Gary Perlmutter, [e-mail]
Date Initiated: May 28, 2024
Division/Branch: NC Division of Water Resources / NPDES Municipal Permitting Unit
Fact Sheet Template: Version 09Jan2017
Permitting Action:
❑ Renewal
❑ Renewal with Expansion
❑ New Discharge
N Modification (Fact Sheet should be tailored to mod request)
Note: A complete application should include the following:
• For New Dischargers, EPA Form 2A or 2D requirements, Engineering Alternatives Analysis, Fee
• For Existing Dischargers (POTW), EPA Form 2A, 3 effluent pollutant scans, 4 2nd species WET
tests.
• For Existing Dischargers (Non-POTW), EPA Form 2C with correct analytical requirements based
on industry category.
Complete applicable sections below. If not applicable, enter NA.
1. Basic Facility Information
Facility Information
Applicant — Facility Name:
City of Lenoir — Lower Creek WWTP
Applicant Address:
P.O. Box 958, Lenoir, NC 28645
Facility Address:
1905 Broadland Rd, Lenoir, NC 28645
Permitted Flow:
6.0 MGD
Facility Type/Waste:
MAJOR Municipal; 87% domestic, 13% industrial 1
Facility Class:
Grade IV
Treatment Units:
Bar Screen, Grit Removal, Activated (aerobic/anaerobic/anoxic)
Sludge, Clarifiers, Sludge Digestion, Chlorination, Dechlorination
Pretreatment Program (Y/N)
Yes
County:
Caldwell
Region
Asheville
From permitted industrial flow of 0.767 MGD.
Briefly describe the proposed permitting action and facility background: The City of Lenoir had requested
a modification to the NPDES permit for its Lower Creek WWTP, submitting an application on March 4,
2024. The permit renewal was issued in June 2021 and included Total Silver limits of 0.14 µg/L monthly
average and 0.93 µg/L daily maximum. The permit also included a three-year compliance schedule with a
Water Effects Ratio (WER) study option to meet the Total Silver limits by August 1, 2024. With the
Page 1 of 5

modification request, the City submitted a WER study report, dated February 2024 and a WER Checklist.
Review of the draft report found errors requiring return to the City for corrections. An amended WER report
was received on May 20, 2023, review of which found it acceptable.
This 6.0 MGD facility serves the communities of Lenoir and Gamewell. The WWTP treats a combination
of domestic and industrial wastewater with a pretreatment program involving three Categorical Industrial
User (CIUs): Stallergenes Greer and two facilities of Exela Pharma Sciences: Augusta and Michelle. All
three CIUs are under 40 CFR 439 — pharmaceutical category.
2. Receiving Waterbody Information
Receiving Waterbody Information
Outfalls/Receiving Stream(s):
Outfall 001/Lower Cr
Stream Segment:
11-39-(0.5)b
Stream Classification:
C
Drainage Area (mi):
47.9
Summer 7Q 10 (cfs)
A 11.75
Winter 7Q10 (cfs):
16.77 Nr
30Q2 (cfs):
-
Average Flow (cfs):
68
IWC (% effluent):
44%
303(d) listed/parameter:
Benthos
Subject to TMDL/parameter:
State-wide Mercury TMDL, Lower Creek Turbidity TMDL
Basin/HUC:
Catawba / 03050101
USGS Topo Quad:
Lenoir, NC
3. Effluent Data Summary and WER study review
Effluent data for Outfall 001 is summarized in Table 1 for the period of August 2021 (effective date of the
current permit) April 2024.
Table 1. Effluent Data Summary Outfall 001.
Parameter
Units
Average
Max
Min
Permit Limit'
Total Silver
µg/L
3.1
< 5
< 0.5
MA = = 0.14
DM 0.93
1 MA = Monthly Average, DM = Daily Maximum.
From the data review, all results were nondetects at < 0.5 and < 5 µg/L except one detection at 0.7 µg/L on
9/6/2022.
Review of the amended WER study report and accompanying checklist found them to be complete and
properly conducted. Four rounds of WER studies were conducted, three using Ceriodaphnia dubia and one
Page 2 of 5

using the Fathead Minnow (Pimephales promelas) as a second species. Study species used are consistent
with the permit toxicity testing requirements [see permit conditions A. (3.) Chronic Toxicity Permit Limit
and A. (4.) Effluent Pollutant Scan: subsection "Additional Toxicity Testing Requirements for Municipal
Permit Renewal."]. No issues were found in the review and the recommended WER-based silver limits
were found to be appropriately derived.
4. Water Quality -Based Effluent Limitations (WQBELs)
Reasonable Potential Analysis (RPA) for Toxicants
If applicable, conduct RPA analysis and complete information below.
The need for toxicant limits is based upon a demonstration of reasonable potential to exceed water quality
standards, a statistical evaluation that is conducted during every permit renewal utilizing the most recent
effluent data for each outfall. The RPA is conducted in accordance with 40 CFR 122.44 (d) (i). The NC
RPA procedure utilizes the following: 1) 95% Confidence Level/95% Probability; 2) assumption of zero
background; 3) use of '/2 detection limit for "less than" values; and 4) streamflows used for dilution
consideration based on 15A NCAC 2B.0206. Effective April 6, 2016, NC began implementation of
dissolved metals criteria in the RPA process in accordance with guidance titled NPDES Implementation of
Instream Dissolved Metals Standards, dated June 10, 2016.
An RPA was run on effluent silver data sampled from August 2021 February 2024, yielding a reasonable
potential to exceed the current permit silver limits of 0.19 µg/L monthly average and 0.93 µg/L daily
maximum, based on several nondetects at < 5 µg/L and one detect at 0.7 µg/L. The WER study
recommended 7.7 µg/L chronic and 7.7 µg/L acute limits were then compared against the effluent data; an
amended RPA was run using the lowest WER of 6.6413 as a multiplier to the instream Total Silver chronic
and acute standards, yielding allowable concentrations of 0.9 µg/L chronic and 6.0 µg/L acute. The
maximum predicted value of 2.8 µg/L was greater than the chronic allowable concentration, resulting in
the finding of a reasonable potential to exceed the chronic WER-based Total Silver stream standard. The
above WER-based chronic and acute allowable concentrations has been placed in the permit as monthly
average and daily maximum limits, respectively. For continued consideration of WER-based silver limits
during the next permit cycle, a special condition has been added requiring the Permittee to run a
confirmation WER study for submittal with the permit renewal application.
Other WQBEL Considerations
If applicable, describe any compliance schedules proposed for this permit renewal in accordance with 15A
NCAC 2K0107(c)(2)(B), 40CFR 122.47, and EPA May 2007 Memo: The current permit has a 3-year
compliance schedule with a WER study option (available for any/all metals) for Silver and Zinc. Based on
the potential issuance of the draft permit modification in July 2024 with an effective date of August 1, 2024,
that being the compliance date for Total Silver and Total Zinc limits, the compliance schedule has been
removed from the permit.
5. Antibacksliding Review
Sections 402(o)(2) and 303(d)(4) of the CWA and federal regulations at 40 CFR 122.44(1) prohibit
backsliding of effluent limitations in NPDES permits. These provisions require effluent limitations in a
reissued permit to be as stringent as those in the previous permit, with some exceptions where limitations
may be relaxed (e.g., based on new information, increases in production may warrant less stringent TBEL
limits, or WQBELs may be less stringent based on updated RPA or dilution).
Are any effluent limitations less stringent than previous permit (YES/NO): Yes.
Page 3 of 5

If YES, confirm that antibacksliding provisions are not violated: Total Silver limits were modified as less
stringent based on results of WER study, using the lowest resulting WER of four rounds as a multiplier to
the current Total Silver standards as site -specific limits.
6. Summary of Proposed Permitting Actions
Table 2. Current Permit Conditions and Proposed Changes.
Parameter
Current Permit'
Proposed Change
Basis for Condition/Change
Flow
MA 6.0 MGD
No change
15A NCAC 213.0505
MA = 0.14 µg/L
WQBEL. Reasonable potential to
DM = 0.93 µg/L
MA = 0.9 µg/L
exceed allowable WER-based
Total Silver
Monitor monthly
DM = 6.0 µg/L
discharge concentration found after
3-yr compliance
Monitor monthly
evaluation of WER study report and
schedule
submitted effluent data.
Compliance
Remove from
Permit modification expected to be
Schedule for Total
Special Condition
permit modification
issued and in effect by the compliance
Silver and Toal Zinc
date of 8/1/2024.
WER confirmation
No requirement
Add special
To verify continued use of WER
condition
consideration in next permit renewal
'MGD = Million gallons per day, MA = Monthly Average, WA = Weekly Average, DM = Daily Maximum.
13. Public Notice Schedule:
Permit to Public Notice: xx/xx/2024.
Per 15A NCAC 2H .0109 & .0111, The Division will receive comments for a period of 30 days following
the publication date of the public notice. Any request for a public hearing shall be submitted to the Director
within the 30 days comment period indicating the interest of the party filing such request and the reasons
why a hearing is warranted.
14. NPDES Division Contact:
If you have questions regarding any of the above information or on the attached permit, please contact Gary
Perlmutter at [phone] or via email at gary.perlmutter(a-bdeq.nc.gov.
15. Fact Sheet Addendum (if applicable):
Were there any changes made since the Draft Permit was public noticed (Yes/No):
If Yes, list changes and their basis below:
Page 4 of 5

16. Fact Sheet Attachments (if applicable):
• WER study report, amended
• WER checklist
• Request to modify permit with application
• Effluent silver data, Aug 2021 — Feb 2024
• Modified RPA
Page 5 of 5

ROY COOPER
Governor
ELIZABETH S. BISER
Secretary
RICHARD E. ROGERS, JR.
Director
City of Lenoir
Attn: Jeff Church, Utilities Dir.
PO Box 958
Lenoir, NC 28645
Subject: Permit Modification
Application No. NCO023981
Lower Creek WWTP
Caldwell County
Dear Applicant:
NORTH CAROLINA
Environmental Quality
March 07, 2024
The Water Quality Permitting Section acknowledges the March 7, 2024, receipt of your permit modification application
and supporting documentation. Your application will be assigned to a permit writer within the Section's NPDES WW
permitting branch. Per G.S. 150B-3 your current permit does not expire until permit decision on the application is made.
Continuation of the current permit is contingent on timely and sufficient application for renewal of the current permit. The
permit writer will contact you if additional information is required to complete your permit renewal. Please respond in a
timely manner to requests for additional information necessary to allow a complete review of the application and renewal
of the permit.
Information regarding the status of your renewal application can be found online using the Department of Environmental
Quality's Environmental Application Tracker at:
https://decl.nc.gov/permits-regulations/permit-quidance/environmental-application-tracker
If you have any additional questions about the permit, please contact the primary reviewer of the application using the
links available within the Application Tracker.
Sinc rely
Wren Th dford
Administrative Assistant
Water Quality Permitting Section
cc: Elisa Triplett-ORC
ec: WQPS Laserfiche File w/application
�D-F North Carolina Department of Envirnnmernal Quality I DWision of Water Resources
AsheW9e Regional Office 1 2090 U5. Hkfiwr y 70 1 5—nanoa. North Carolina 28778
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ff RECEIVED
F LEMAR 0 7 2024
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Lower Creek Wastewater Treatment
Public Utilities
PO Box 958
Lenoir, NC 28645
March 4, 2024
Gary Perlmutter, NC DENR/Division of Water Quality
NPDES Permitting Unit
1617 Mail Service Center
Raleigh, NC 27699-1617
SUBJECT: Major Permit Modification Request for the City of Lenoir Lower Creek WWTP NCO023981
Dear Mr. Perlmutter,
The City of Lenoir would like to request a major permit modification of the NPDES
NCO023981 wastewater treatment discharge for the City of Lenoir Lower Creek
Wastewater Treatment plant. The current permit expires 212812026. 1 am
requesting a less stringent Silver limit in accordance to favorable data results that
have been submitted from a WER study conducted by ETT Environmental, Inc.
I have included the NPDES Form 2A Application for a major modification.
Thank you for your assistance.
Sincerely,
Elisa Triplett, WWTP Superintendent
[e-mail]
[phone]

FACILITY NAME AND PERMIT NUMBER:
PERMIT ACTION REQUESTED:
Lower Creek WWTP, NCO023981
Major Modification
Catawba
BASIC APPLICATION INFORMATION
PART A. BASIC APPLICATION INFORMATION FOR ALL APPLICANTS:
All treatment works must complete questions A.1 through A.8 of this Basic Application Information Packet.
A.I. Facility Information.
Facility Name Lower Creek WWTP Poll on
RECEIVED
Mailing Address PO Box 958
Lenoir, NC 28645 MAR 0 7 2024
Contact Person Elisa Triplett
Title Plant Superintendent
Telephone Number [phone]
Facility Address 1905 Broadland Road
(not P.O. Box) Lenoir, NC 28645
A.2. Applicant Information. If the applicant is different from the above, provide the following:
Applicant Name City of Lenoir
Mailing Address PO Box 958
Lenoir, NC 28645
Contact Person Mr. Jeff Church
Title Public Utilities Operations Manager
Telephone Number [phone]
Is the applicant the owner or operator (or both) of the treatment works?
X❑ owner ❑ operator
Indicate whether correspondence regarding this permit should be directed to the facility or the applicant.
X❑ facility ❑ applicant
A.3. Existing Environmental Permits. Provide the permit number of any existing environmental permits that have been issued to the treatment works
(include state -issued permits).
NPDES NCO023981 PSD
UIC Other
RCRA Other
A.4. Collection System Information. Provide information on municipalities and areas served by the facility. Provide the name and population of each
entity and, if known, provide information on the type of collection system (combined vs. separate) and its ownership (municipal, private, etc.).
Name Population Served Type of Collection System Ownership
Lenoir 18,219 separate municipal
Gamewell 4,028 separate municipal
Total population served 22,245
EPA Form 3510-2A (Rev. 1-99). Replaces EPA forms 7550-6 & 7550-22. Page 2 of 22

FACILITY NAME AND PERMIT NUMBER: PE�Major
TION REQUESTED: RIVER BASIN:
Lower Creek WWTP, NCO023981 Modification Catawba
A.S. Indian Country.
a. Is the treatment works located in Indian Country?
Yes X❑ No
b. Does the treatment works discharge to a receiving water that is either in Indian Country or that is upstream from (and eventually flows
through) Indian Country?
❑ Yes X❑ No
A.S. Flow. Indicate the design flow rate of the treatment plant (i.e., the wastewater flow rate that the plant was built to handle). Also provide the
average daily flow rate and maximum daily flow rate for each of the last three years. Each year's data must be based on a 12-month time period
with the 1211 month of "this year" occurring no more than three months prior to this application submittal.
a. Design flow rate 6.0 mgd
Two Years Ago(2017) Last Year(2018) This Year(1/2 2019)
b. Annual average daily flow rate 2.678 3.055 2.848
C. Maximum daily flow rate 7.25 7.636 5.269
A.7. Collection System. Indicate the type(s) of collection system(s) used by the treatment plant. Check all that apply. Also estimate the percent
contribution (by miles) of each.
X❑ Separate sanitary sewer 100
Combined storm and sanitary sewer %
A.8. Discharges and Other Disposal Methods.
a. Does the treatment works discharge effluent to waters of the U.S.? X❑ Yes ❑ No
If yes, list how many of each of the following types of discharge points the treatment works uses:
i. Discharges of treated effluent
ii. Discharges of untreated or partially treated effluent
iii. Combined sewer overflow points
iv. Constructed emergency overflows (prior to the headworks) 0
V. Other 0
b. Does the treatment works discharge effluent to basins, ponds. or other surface impoundments
that do not have outlets for discharge to waters of the U.S.? ❑ Yes X❑ No
If yes, provide the following for each surface impoundment:
Location:
Annual average daily volume discharge to surface impoundment(s) mgd
Is discharge ❑ continuous or ❑ intermittent?
C. Does the treatment works land -apply treated wastewater? ❑ Yes X❑ No
If yes, provide the following for each land application site:
Location.
Number of acres:
Annual average daily volume applied to site: mgd
Is land application ❑ continuous or ❑ intermittent?
d. Does the treatment works discharge or transport treated or untreated wastewater to another
treatment works? ❑ Yes X❑ No
EPA Form 3510-2A (Rev. 1-99). Replaces EPA forms 7550-6 & 7550-22. Page 3 of 22

FACILITY NAME AND PERMIT NUMBER:
PERMIT ACTION REQUESTED:
RIVER BASIN:
Lower Creek WWTP, NCO023981
Major Modification
Catawba
If yes, describe the mean(s) by which the wastewater from the treatment works is discharged or transported to the other treatment works
(e.g., tank truck, pipe).
If transport is by a party other than the applicant, provide:
Transporter Name
Mailing Address
Contact Person
Title
Telephone Number ( )
For each treatment works that receives this discharge, provide the following:
Name
Mailing Address
Contact Person
Title
Telephone Number )
If known, provide the NPDES permit number of the treatment works that receives this discharge
Provide the average daily flow rate from the treatment works into the receiving facility.
mgd
e. Does the treatment works discharge or dispose of its wastewater in a manner not included
in A.8. through A.8.d above (e.g., underground percolation, well injection): ❑ Yes
X❑ No
If yes, provide the following for each disposal method:
Description of method (including location and size of site(s) if applicable):
Annual daily volume disposed by this method:
Is disposal through this method ❑ continuous or ❑ intermittent?
EPA Form 3510-2A (Rev. 1-99). Replaces EPA forms 7550-6 & 7550-22. Page 4 of 22

FACILITY NAME AND PERMIT NUMBER: PERMIT ACTION REQUESTED: RIVER BASIN:
Lower Creek WWTP, NCO023981 Major Modification Catawba
WASTEWATER DISCHARGES:
If you answered "Yes" to question A.8.a, complete questions A.9 through A.12 once for each outfall (including bypass points) through
which effluent is discharged. Do not include information on combined sewer overflows in this section. If you answered "No" to question
A.8.a, go to Part B, "Additional Application Information for Applicants with a Design Flow Greater than or Equal to 0.1 mgd."
A.9. Description of Outfall.
a.
Outfall number 001
b.
Location Lenoir
28645
(City or town, if applicable)
(Zip Code)
Caldwell
NC
(County)
(State)
35 52'55"
-81 34'35"
(Latitude)
(Longitude)
C.
Distance from shore (if applicable) N/A
ft
d.
Depth below surface (if applicable) N/A
ft
e.
Average daily flow rate 2.771
mgd
f.
Does this ouffall have either an intermittent or a periodic discharge? ❑ Yes
X❑ No (go to A.9.g.)
If yes, provide the following information:
Number f times per year discharge occurs:
Average duration of each discharge:
Average flow per discharge:
mgd
Months in which discharge occurs:
g.
Is ouffall equipped with a diffuser? ❑ Yes
X❑ No
A.10. Description of Receiving Waters.
a. Name of receiving water Lower Creek
b. Name of watershed (if known)
United States Soil Conservation Service 14-digit watershed code (if known):
C. Name of State Management/River Basin (if known): Catawba River Basin
United States Geological Survey 8-digit hydrologic cataloging unit code (if known):
d. Critical low flow of receiving stream (if applicable)
acute cfs chronic cfs
e. Total hardness of receiving stream at critical low flow (if applicable). mg/l of CaCO3
EPA Form 3510-2A (Rev. 1-99). Replaces EPA forms 7550-6 & 7550-22. Page 5 of 22

FACILITY NAME AND PERMIT NUMBER:
PERMIT ACTION REQUESTED:
RIVER BASIN:
Lower Creek WWTP, NCO023981
Major Modification
Catawba
A.11. Description of Treatment
a. What level of treatment are provided? Check all that apply.
Primary X ❑ Secondary
X❑ Advanced ❑ Other. Describe:
b. Indicate the following removal rates (as applicable):
Design BOD5 removal or Design CBOD5 removal 95 %
Design SS removal 95
Design P removal N/A
Design N removal 85
Other
C. What type of disinfection is used for the effluent from this outfall? If disinfection varies by season, please describe:
Chlorination using chlorine gas
If disinfection is by chlorination is dechlorination used for this outfall? X❑ Yes ❑ No
Does the treatment plant have post aeration? ❑ Yes X C No
A.12. Effluent Testing Information. All Applicants that discharge to waters of the US must provide effluent testing data for the following
parameters. Provide the indicated effluent testing required by the permitting authority for each outfall through which effluent is
discharged. Do not include information on combined sewer overflows in this section. All information reported must be based on data
collected through analysis conducted using 40 CFR Part 136 methods. In addition, this data must comply with QA/QC requirements of
40 CFR Part 136 and other appropriate QA/QC requirements for standard methods for analytes not addressed by 40 CFR Part 136. At a
minimum, effluent testing data must be based on at least three samples and must be no more than four and one-half years apart.
Outfall number: 00'
MAXIMUM DAILY VALUE
AVERAGE DAILY VALUE
PARAMETER
Value
Units
Value
Units
Number of Samples
pH (Minimum)
6.0
S.U.
pH (Maximum)
8.8
S.U.
Flow Rate
7.77
MGD
2.771
MGD
1642
Temperature (Winter)
22.6
°C
11.3
°C
458
Temperature (Summer)
28.4
°C
21.1
°C
660
For pH please report a minimum and a maximum daily value
MAXIMUM DAILY
AVERAGE DAILY DISCHARGE
POLLUTANT
DISCHARGE
ANALYTICAL
ML/MDL
Conc.
Units
Conc.
Units
Number of
METHOD
Samples
CONVENTIONAL AND NON CONVENTIONAL COMPOUNDS
BIOCHEMICAL OXYGEN
BOD5
22.0
mg/1
4.1
mg/l
1118
SM 521OB-2001
2.0
DEMAND
(Hach LDO)
(Report one)
CBOD5
FECAL COLIFORM
11,000
/100m1
11
/100ml
1118
SM 9222D-1997
1
TOTAL SUSPENDED SOLIDS (TSS)
280
1 m /I
8.6
m /I
1118
SM 254OD-1997
2.5
END OF PART A.
REFER TO THE APPLICATION OVERVIEW (PAGE 1) TO DETERMINE WHICH OTHER PARTS
OF FORM 2A YOU MUST COMPLETE
EPA Form 3510-2A (Rev. 1-99). Replaces EPA forms 7550-6 & 7550-22. Page 6 of 22

FACILITY NAME AND PERMIT NUMBER:
PERMIT ACTION REQUESTED:
RIVER BASIN:
Lower Creek WWTP, NCO023981
Major Modification
Catawba
BASIC APPLICATION INFORMATION
PART B. ADDITIONAL APPLICATION INFORMATION FOR APPLICANTS WITH A DESIGN FLOW GREATER THAN OR
EQUAL TO 0.1 MGD (100,000 gallons per day).
All applicants with a design flow rate >_ 0.1 mgd must answer questions BA through B.6. All others go to Part C (Certification).
B.1. Inflow and Infiltration. Estimate the average number of gallons per day that flow into the treatment works from inflow and/or infiltration.
105,000 gpd
Briefly explain any steps underway or planned to minimize inflow and infiltration.
Active inspection and repair program utilized by the City of Lenoir wastewater collections division
B.2. Topographic Map. Attach to this application a topographic map of the area extending at least one mile beyond facility property boundaries. This
map must show the outline of the facility and the following information. (You may submit more than one map if one map does not show the entire
area.)
a. The area surrounding the treatment plant, including all unit processes.
b. The major pipes or other structures through which wastewater enters the treatment works and the pipes or other structures through
which
treated wastewater is discharged from the treatment plant. Include outfalls from bypass piping, if applicable.
c. Each well where wastewater from the treatment plant is injected underground.
d. Wells, springs, other surface water bodies, and drinking water wells that are: 1) within '/4 mile of the property boundaries of the treatment
works, and 2) listed in public record or otherwise known to the applicant.
e. Any areas where the sewage sludge produced by the treatment works is stored, treated, or disposed.
f. If the treatment works receives waste that is classified as hazardous under the Resource Conservation and Recovery Act (RCRA) by truck, rail,
or special pipe, show on the map where the hazardous waste enters the treatment works and where it is treated, stored, and/or disposed.
B.3. Process Flow Diagram or Schematic. Provide a diagram showing the processes of the treatment plant, including all bypass and all
piping
backup power sources or redunancy in the system. Also provide a water balance showing all treatment units, including disinfection (e.g.,
chlorination and dechlorination). The water balance must show daily average flow rates at influent and discharge points and approximate daily flow
rates between treatment units. Include a brief narrative description of the diagram.
B.4. Operation/Maintenance Performed by Contractor(s).
Are any operational or maintenance aspects (related to wastewater treatment and effluent quality) of the treatment works the responsibility of a
contractor? ❑ Yes X❑ No
If yes, list the name, address, telephone number, and status of each contractor and describe the contractor's responsibilities (attach additional
pages if necessary).
Name:
Mailing Address:
Telephone Number: f a
Responsibilities of Contractor:
B.5. Scheduled improvements and Schedules of Implementation. Provide information on any uncompleted implementation schedule or
uncompleted plans for improvements that will affect the wastewater treatment, effluent quality, or design capacity of the treatment works. If the
treatment works has several different implementation schedules or is planning several improvements, submit separate responses to question B.5
for each. (If none, go to question B.6.)
a. List the outfall number (assigned in question A.9) for each outfall that is covered by this implementation schedule.
N/A
b. Indicate whether the planned improvements or implementation schedule are required by local, State, or Federal agencies.
❑ Yes X❑ No
EPA Form 3510-2A (Rev. 1-99). Replaces EPA forms 7550-6 & 7550-22. Page 7 of 22

FACILITY NAME AND PERMIT NUMBER:
PERMIT ACTION REQUESTED:
RIVER BASIN:
Major Modification
Catawba
Lower Creek WWTP, NCO023981
C. If the answer to B.5.b is "Yes," briefly describe, including new maximum daily inflow rate (if applicable).
d. Provide dates imposed by any compliance schedule or any actual dates of completion for the implementation steps listed below, as
applicable. For improvements planned independently of local, State, or Federal agencies, indicate planned or actual completion dates, as
applicable. Indicate dates as accurately as possible.
Schedule Actual Completion
Implementation Stage MM/DD/YYYY MM/DD/YYYY
Begin Construction
End Construction
Begin Discharge
Attain Operational Level
e. Have appropriate permits/clearances concerning other Federal/State requirements been obtained? ❑ Yes ❑ No
Describe briefly:
B.6. EFFLUENT TESTING DATA (GREATER THAN 0.1 MGD ONLY).
Applicants that discharge to waters of the US must provide effluent testing data for the following parameters. Provide the indicated
effluent testing required by the permitting authority for each outfall through which effluent is discharged. Do not include information
on combine sewer overflows in this section. All information reported must be based on data collected through analysis conducted
using 40 CFR Part 136 methods. In addition, this data must comply with QA/QC requirements of 40 CFR Part 136 and other appropriate
QA/QC requirements for standard methods for analytes not addressed by 40 CFR Part 136. At a minimum effluent testing data must be
based on at least three pollutant scans and must be no more than four and on -half years old.
Outfall Number: 001
MAXIMUM DAILY
AVERAGE DAILY DISCHARGE
POLLUTANT
DISCHARGE
ANALYTICAL
MUMDL
Conc.
Units
Con
Units
Number of
METHODc.
Samples
CONVENTIONAL AND NON CONVENTIONAL COMPOUNDS
AMMONIA (as N)
10.2
mg/I
0.68
mg/I
1118
SM 4500NH3 D-
0.25
1997
CHLORINE (TOTAL
50
Ngll
13 (<20)
Ng/I
1118
SM 4500CI G
20
RESIDUAL, TRC)
2000
DISSOLVED OXYGEN
11.0
mgll
8.5
mg/I
1118
SM 4500 O G2001
0.1
(Hach LDO)
TOTAL HL
SM 4500 Norg B
NITROGEENN (TKTKN)
12.6
mg/I
4.98
mg/I
125
1997 (NH3 D-
0.25
1997)
NITRATE PLUS NITRITE
8.17
mg/l
4.5
mg/1
125
SM 450ONO3 D-
0.10
NITROGEN
1997
OIL and GREASE
1.6
mg/1
<1.0
mg/I
3
SM 191h 5520B
1.0
PHOSPHORUS (Total)
9.05
mg/1
2.47
mgll
125
SM 4500 P E
0.05
1999
TOTAL DISSOLVED SOLIDS
185
mg/1
86
mg/I
3
SM 19th 2540C
1
(TDS)
OTHER
END OF PART B.
REFER TO THE APPLICATION OVERVIEW (PAGE 1) TO DETERMINE WHICH OTHER PARTS
OF FORM 2A YOU MUST COMPLETE
EPA Form 3510-2A (Rev. 1-99). Replaces EPA forms 7550-6 & 7550-22. Page 8 of 22

FACILITY NAME AND PERMIT NUMBER:
PERMIT ACTION REQUESTED:
RIVER BASIN:
Lower Creek WWTP, NCO023981
Major Modification
Catawba
BASIC APPLICATION INFORMATION
PART C. CERTIFICATION
All applicants must complete the Certification Section. Refer to instructions to determine who is an officer for the purposes of this
certification. All applicants must complete all applicable sections of Form 2A, as explained in the Application Overview. Indicate below which
parts of Form 2A you have completed and are submitting. By signing this certification statement, applicants confirm that they have reviewed
Form 2A and have completed all sections that apply to the facility for which this application is submitted.
Indicate which parts of Form 2A you have completed and are submitting:
x❑ Basic Application Information packet Supplemental Application Information packet:
X❑ Part D (Expanded Effluent Testing Data)
X❑ Part E (Toxicity Testing: Biomonitoring Data)
X❑ Part F (Industrial User Discharges and RCRA/CERCLA Wastes)
❑ Part G (Combined Sewer Systems)
ALL APPLICANTS MUST COMPLETE THE FOLLOWING CERTIFICATION.
I certify under penalty of law that this document and all attachments were prepared under my direction or supervision in accordance with a system
designed to assure that qualified personnel properly gather and evaluate the information submitted. Based on my inquiry of the person or persons who
manage the system or those persons directly responsible for gathering the information, the information is, to the best of my knowledge and belief, true,
accurate, and complete. I am aware that there are significant penalties for submitting false information, including the possibility of fine and imprisonment
for knowing violations.
Name and official title Jeff Church , Public Utilities Operations Manager
Signaturure J�'11 Cch'
Telephone number [phone]
Date signed 31112024
Upon request of the permitting authority, you must submit any other information necessary to assure wastewater treatment practices at the treatment
works or identify appropriate permitting requirements.
SEND COMPLETED FORMS TO:
NCDENR/ DWQ
Attn: NPDES Unit
1617 Mail Service Center
Raleigh, North Carolina 27699-1617
EPA Form 3510-2A (Rev. 1-99). Replaces EPA forms 7550-6 & 7550-22. Page 9 of 22

FACILITY NAME AND PERMIT NUMBER:
Lower Creek WWTP, NCO023981
PERMIT ACTION REQUESTED:
Major Modification
RIVER BASIN:
Catawba
SUPPLEMENTAL APPLICATION INFORMATION
PART D. EXPANDED EFFLUENT TESTING DATA
Refer to the directions on the cover page to determine whether this section applies to the treatment works.
Effluent Testing: 1.0 mgd and Pretreatment Works. If the treatment works has a design flow greater than or equal to 1.0 mgd or it has (or is required
to have) a pretreatment program, or is otherwise required by the permitting authority to provide the data, then provide effluent testing data for the following
pollutants. Provide the indicated effluent testing information and any other information required by the permitting authority for each outfall through which
effluent is discharged. Do not include information on combined sewer overflows in this section. All information reported must be based on data collected
through analyses conducted using 40 CFR Part 136 methods. In addition, these data must comply with QA/QC requirements of 40 CFR Part 136 and
other appropriate QA/QC requirements for standard methods for analytes not addressed by 40 CFR Part 136. Indicate in the blank rows provided below
any data you may have on pollutants not specifically listed in this form. At a minimum, effluent testing data must be based on at least three pollutant
scans and must be no more than four and one-half years old.
Outfall number: 001 (Complete once for each outfall discharging effluent to waters of the United States.)
POLLUTANT
MAXIMUM DAILY DISCHARGE
AVERAGE DAILY DISCHARGE
ANALYTICAL
METHOD
MUMDL
Conc.
Units
Mass
Units
Conc.
Units
Mass
Units
Number
of
Samples
METALS (TOTAL RECOVERABLE), CYANIDE, PHENOLS, AND HARDNESS.
ANTIMONY
<10
pg/I
<10
N9/1
3
EPA 200.7
10
ARSENIC
<10
Ng/I
<10
Ng/I
15
EPA 200.7
EPA 200.8
10: 1.0
BERYLLIUM
<1
pg/l
<1
Ng/I
3
EPA 200.7
1
CADMIUM
5
pg/I
<0.2
g/1
FP
F
55
EPA 200.7
0.2
CHROMIUM
4
pg/I
<1
ug/I
18
EPA 200.7
1
COPPER
25
Pg/I
5.5
Ng/I
35
EPA 200.7
1
LEAD
1.9
p9 /I
<0.5
Vg/l
15
EPA 200.7
EPA 200.8
0.5 ; 1.0
MERCURY
9.4
pg/I
2.14
pg/I
17
EPA 1631
0.0010
NICKEL
0.5
pg/I
5
pg/I
35
EPA 200.7
1
SELENIUM
<2
pg/1
<1
pg/I
34
EPA 200.7
EPA 200.8
2: 1
SILVER
5
ug/I
0.24
Ng/I
33
EPA 200.7
1
THALLIUM
<20
pg/I
<7
Ng/I
3
EPA 200.7
1 ; 20
ZINC
161
pg/I
12
Ng/I
17
EPA 200.7
1
CYANIDE
8
pg/I
1.5
pg/I
35
SM 191" 4500-
C
5
TOTAL PHENOLIC
COMPOUNDS
<10
Ng/l
<10
pg/I
3
EPA 625
5
HARDNESS (as CaCO3)
98.7
mg/l
45.0
mg/t
15
SM 191" 2340-
B
0.03
Use this space (or a separate sheet) to provide information on other metals requested by the permit writer
EPA Form 3510-2A (Rev. 1-99). Replaces EPA forms 7550-6 & 7550-22. Page 10 of 22

FACILITY NAME AND PERMIT NUMBER:
PERMIT ACTION REQUESTED:
RIVER BASIN:
Lower Creek WWTP, NCO023981
Major Modification
Catawba
Outfall number: 001 (Complete once for each outfall discharging effluent to waters of the United States.)
MAXIMUM DAILY DISCHARGE
AVERAGE DAILY DISCHARGE
Number
POLLUTANT
ANALYTICAL
Conc.
Units
Mass
Units
Conc.
Units
Mass
Units
of
METHOD
MUMDL
Samples
VOLATILE ORGANIC COMPOUNDS
ACROLEIN
<50
Ng/I
<50
Ng/1
3
EPA 624
50
ACRYLONITRILE
<50
pg/I
<50
Ng/I
3
EPA 624
50
BENZENE
<5
Ng/I
<5
Ng/1
3
EPA 624
5
BROMOFORM
<5
Ng/I
<5
vg/I
3
EPA 624
5
CARBON
TETRACHLORIDE
<5
Yg/I
<5
Ng/I
3
EPA 624
5
CHLOROBENZENE
<5
pg/1
<5
Ng/I
3
EPA 624
5
CHLORODIBROMO-
METHANE
<5
Ng/I
<5
pg/I
3
EPA 624
5
CHLOROETHANE
<5
Ng/I
<5
Ng/1
3
EPA 624
5
2-CHLOROETHYLVINYL
ETHER
<10
pg/I
<10
pg/I
3
EPA 624
10
CHLOROFORM
<5
Ng/I
<5
Ng/1
3
EPA 624
5
DICHLOROBROMO-
METHANE
<5
Ng/I
<5
Ng/1
3
EPA 624
5
1,1-DICHLOROETHANE
<5
Ng/I
<5
ug/I
3
EPA 624
5
1,2-DICHLOROETHANE
<5
Ng/I
<5
Ngll
3
EPA 624
5
TRANS-I,2-DICHLORO-
ETHYLENE
<5
Ng/I
<5
pgll
3
EPA 624
5
1,1-DICHLORO-
ETHYLENE
<5
pg/I
<5
Ngll
3
EPA 624
5
1,2-DICHLOROPROPANE
<5
ug/I
<5
Pg/l
3
EPA 624
5
1,3-DICHLORO-
PROPYLENE
<5
Pg/I
<5
Ng/I
3
EPA 624
5
ETHYLBENZENE
<5
Ng/I
<5
Ng/I
3
EPA 624
5
METHYL BROMIDE
6.28
Ng/I
<5
pg/I
3
EPA 624
5
METHYL CHLORIDE
<5
pg/1
<5
Ng/l
3
EPA 624
5
METHYLENE CHLORIDE
<5
Ng/I
<5
pgll
3
EPA 624
5
1,1, 2, 2-TETRA-
CHLOROETHANE
<5
pg/I
<5
pg/I
3
EPA 624
5
TETRACHLORO-
ETHYLENE
<5
Ng/I
<5
Ng/I
3
EPA 624
5
TOLUENE
<5
ug/I
<5
Ng/I
3
EPA 624
5
EPA Form 3510-2A (Rev. 1-99). Replaces EPA forms 7550-6 & 7550-22. Page 11 of 22

FACILITY NAME AND PERMIT NUMBER:
Lower Creek WWTP, NCO023981
PERMIT ACTION REQUESTED:
Major Modification
RIVER BASIN:
Catawba
Outfall number: 001 (Complete once for each outfall discharging effluent to waters of the United States.)
POLLUTANT
MAXIMUM DAILY DISCHARGE
AVERAGE DAILY DISCHARGE
ANALYTICAL
METHOD
ML/MDL
Conc.
Units
Mass
Units
Conc.
Units
Mass
Units
Number
of
Samples
TRICHLOROETHANE
<5
Ng/I
<5
Ng/I
3
EPA 624
5
TRICHLOROETHANE
<5
Ng/I
<5
Ng/I
3
EPA 624
5
TRICHLOROETHYLENE
<5
Ng/1
<5
Ng/I
3
EPA 624
5
VINYL CHLORIDE
<5
Ng/I
<5
pg/I
3
EPA 624
5
Use this space (or a separate sheet) to provide information on other volatile organic compounds requested by the permit writer
_F_T__F_7_T___7_
—
I
I __
�
ACID -EXTRACTABLE COMPOUNDS
P-CHLORO-M-CRESOL
<5
Ng/I
<5
Ng/I
3
EPA 625
5
2-CHLOROPHENOL
<5
Ng/I
<5
Ng/I
3
EPA 625
5
2.4-DICHLOROPHENOL
<5
Pg/I
<5
pg/l
3
EPA 625
5
2,4-DIMETHYLPHENOL
<5
Ng/I
<5
pg/I
3
EPA 625
5
4,6-DINITRO-0-CRESOL
<74
Ng/I
<5
pg/I
3
EPA 625
5: 74
2,4-DINITROPHENOL
<84
Ng/I
<26
Pg/I
3
EPA 625
26: 27; 84
2-NITROPHENOL
<5
Ng/I
<5
Ng/I
3
EPA 625
5
4-NITROPHENOL
<42
Ng/I
<17
Ng/I
3
EPA 625
5 : 42
PENTACHLOROPHENOL
<29
pg/I
<26
pg/I
3
EPA 625
25 : 26; 29
PHENOL
<5
Ng/I
<5
Ng/I
3
EPA 625
5
2 4 6
TRICHLOROPHENOL
<5
N9/I
<5
N9/I
3
EPA 625
5
Use this space (or a separate sheet) to provide information on other acid -extractable compounds requested by the permit writer
T_
BASE -NEUTRAL COMPOUNDS
ACENAPHTHENE
<5
pg/I
<5
pg/1
3
EPA 625
5
ACENAPHTHYLENE
<5
Ng/I
<5
Ng/I
3
EPA 625
5
ANTHRACENE
<5
Ng/I
<5
Ng/I
3
EPA 625
5
BENZIDINE
<89
Ng/I
<33
Ng/I
3
EPA 625
5 ; 89
BENZO(A)ANTHRACENE
<5
Ng/I
<5
pg/I
3
EPA 625
5
BENZO(A)PYRENE
<5
Ng/I
<5
Ng/I
3
EPA 625
5
EPA Form 3510-2A (Rev. 1-99). Replaces EPA forms 7550-6 & 7550-22. Page 12 of 22

FACILITY NAME AND PERMIT NUMBER:
PERMIT ACTION REQUESTED:
RIVER BASIN:
Lower Creek WWTP, NCO023981
Major Modification
Catawba
Outfall number: 001 (Complete once for each outfall discharging effluent to waters of the United States.)
MAXIMUM DAILY DISCHARGE
AVERAGE DAILY DISCHARGE
Number
POLLUTANT
ANALYTICAL
Conc.
Units
Mass
Units
Conc.
Units
Mass
Units
of
METHOD
ML/MDL
Samples
3,4 BENZO-
FLUORANTHENE
<10
Ng/I
<7
Ng/I
3
EPA 625
5: 5.4 ;10
BENZO(GHI)PERYLENE
<16
Pg/1
8.8
pg/I
3
EPA 625
5 ; 16
BENZO(K)
FLUORANTHENE
<5
Ng/I
<5
Ng/I
3
EPA 625
5
BIS OROETHOXY)
METHANE
<5
vgll
<5
pg/I
3
EPA 625
5
BIS (2- HLOROETHYL)-
ETHER
<5
Ng/I
<5
pg/I
3
EPA 625
5
BIS (2-CHLOROISO-
PROPYL) ETHER
<5
Ng/I
<5
N9/1
3
EPA 625
5
BIS (2-ETHYLHEXYL)
PHTHALATE
<32
Ng/I
<32
Ng/I
3
EPA 625
5; 10; 84
4-BROMOPHENYL
PHENYL ETHER
<5
Ng/I
<5
N9/I
3
EPA 625
5
BUTYL BENZYL
PHTHALATE
<10
Ng/1
<7
Ng/I
3
EPA 625
5: 10
2-CHLORO-
NAPHTHALENE
<5
Ngll
<5
Ng/I
3
EPA 625
5
4-CHLORPHENYL
PHENYL ETHER
<5
pg/1
<5
Pg/I
3
EPA 625
5
CHRYSENE
<5
Ng/I
<5
pg/I
3
EPA 625
5
DI-N-BUTYL PHTHALATE
<5
Ng/I
<5
Ng/I
3
EPA 625
5
DI-N-OCTYL PHTHALATE
<32
pgll
<4
Ng/I
3
EPA 625
5: 32
DIBENZO(A,H)
ANTHRACENE
<53
Ng/I
<21
Ng/I
3
EPA 625
5; 53
1,2-DICHLOROBENZENE
<5
Ng/I
<5
Ng/I
3
EPA 625
5
1,3-DICHLOROBENZENE
<5
Ng/I
<5
Ng/I
3
EPA 625
5
1,4-DICHLOROBENZENE
<5
Ng/1
<5
Ng/I
3
EPA 625
5
3,3-DICHLORO-
BENZIDINE
<63
Ng/I
<5
ug/I
3
EPA 625
5 : 63
DIETHYL PHTHALATE
<5
Ng/I
<5
ug/I
3
EPA 625
5
DIMETHYL PHTHALATE
<5
Vg/I
<5
Ng/I
3
EPA 625
5
2,4-DINITROTOLUENE
<5
Ng/l
<5
Ng/I
3
EPA 625
5
2,6-DINITROTOLUENE
<5
Ng/I
<5
Ngll
3
EPA 625
5
1,2-DIPHENYL-
HYDRAZINE
<21
Ng/1
<21
Ng/I
3
EPA 625
21
EPA Form 3510-2A (Rev. 1-99). Replaces EPA forms 7550-6 & 7550-22. Page 13 of 22

FACILITY NAME AND PERMIT NUMBER: PERMIT ACTION REQUESTED: RIVER BASIN:
Lower Creek WWTP, NCO023981 Major Modification Catawba
Outfall number: 001
(Complete once for each outfall discharging effluent to waters of the United States.)
MAXIMUM DAILY DISCHARGE
AVERAGE DAILY DISCHARGE
POLLUTANT
Number
ANALYTICAL
Conic.
Units
7MassUnits
Conic.
Units
Mass
Units
of
METHOD
MUMDL
Samples
FLUORANTHENE
<5
pg/I
<5
pg/I
3
EPA 625
5
FLUORENE
<5
Ng/I
<5
pg/I
3
EPA 625
5
HEXACHLOROBENZENE
<5
Ng/l
<5
Ng/I
3
EPA 625
5
HEXACHLORO-
BUTADIENE
<5
Ng/I
<5
Ngll
3
EPA 625
5
HEXACHLOROCYCLO-
PENTADIENE
<5
Ng/I
<35
Ng/I
3
EPA 625
5: 60
HEXACHLOROETHANE
<5
pg/I
<5
pg/I
3
EPA 625
5
INDENO(1,2,3-CD)
PYRENE
<5
Ng/I
<8
Ngll
3
EPA 625
5: 15
ISOPHORONE
<5
pg/I
<5
Ngll
3
EPA 625
5
NAPHTHALENE
<5
pg/1
<5
pgll
3
EPA 625
5
NITROBENZENE
<5
Ngll
<5
Ngll
3
EPA 625
5
N-NITROSODI-N-
PROPYLAMINE
<5
vg/I
<5
pgll
3
EPA 625
5
N-NITROSODI-
METHYLAMINE
<5
ug/l
<5
pgll
3
EPA 625
5
N-NITROSODI-
PHENYLAMINE
<5
Ng/I
<5
Ng/I
3
EPA 625
5
PHENANTHRENE
<5
Ng/l
<5.3
Ng/I
3
EPA 625
5.1: 5* 3;
5.4
PYRENE
<5
Ng/I
<5.3
Ng/I
3
EPA 625
5.1; 5.3;
5.4
1,2.4-
TRICHLOROBENZENE
<5
Ng/1
<5
Ng/I
3
EPA 625
5
Use this space (or a separate sheet) to provide information on other base -neutral compounds requested by the permit writer
- J
I
�
Use this space (or a separate sheet) to provide information on other pollutants (e.g., pesticides) requested by the permit writer
END OF PART D.
REFER TO THE APPLICATION OVERVIEW (PAGE 1) TO DETERMINE WHICH OTHER PARTS
OF FORM 2A YOU MUST COMPLETE
EPA Form 3510-2A (Rev. 1-99). Replaces EPA forms 7550-6 & 7550-22_ Page 14 of 22

FACILITY NAME AND PERMIT NUMBER:
PERMIT ACTION REQUESTED:
RIVER BASIN:
Lower Creek WWTP, NCO023981
Major Modification
Catawba
SUPPLEMENTAL APPLICATION INFORMATION
PART E. TOXICITY TESTING DATA
POTWs meeting one or more of the following criteria must provide the results of whole effluent toxicity tests for acute or chronic toxicity for each of the
facility's discharge points: 1) POTWs with a design flow rate greater than or equal to 1.0 mgd' 2) POTWs with a pretreatment program (or those that are
required to have one under 40 CFR Part 403), or 3) POTWs required by the permitting authority to submit data for these parameters.
• At a minimum, these results must include quarterly testing for a 12-month period within the past 1 year using multiple species (minimum of two
species), or the results from four tests performed at least annually in the four and one-half years prior to the application, provided the results
show no appreciable toxicity, and testing for acute and/or chronic toxicity, depending on the range of receiving water dilution. Do not include
information on combined sewer overflows in this section. All information reported must be based on data collected through analysis conducted
using 40 CFR Part 136 methods. In addition, this data must comply with QA/QC requirements of 40 CFR Part 136 and other appropriate QA/QC
requirements for standard methods for analytes not addressed by 40 CFR Part 136.
• In addition, submit the results of any other whole effluent toxicity tests from the past four and one-half years. If a whole effluent toxicity test
conducted during the past four and one-half years revealed toxicity, provide any information on the cause of the toxicity or any results of a
toxicity reduction evaluation, if one was conducted.
• If you have already submitted any of the information requested in Part E, you need not submit it again. Rather, provide the information
requested in question EA for previously submitted information. If EPA methods were not used, report the reasons for using alternate methods.
If test summaries are available that contain all of the information requested below, they may be submitted in place of Part E.
If no biomonitoring data is required, do not complete Part E. Refer to the Application Overview for directions on which other sections of the form to
complete.
E.1. Required Tests.
Indicate the number of whole effluent toxicity tests conducted in the past four and one-half years.
220 chronic ❑ acute
E.2. Individual Test Data. Complete the following chart for each whole effluent toxicity test conducted in the last four and one-half years. Allow one
column per test (where each species constitutes a test). Copy this page if more than three tests are being reported.
Test number: 001 Test number: 002 Test number: 003
a. Test information.
Test Species & test method number
Ceriodaphnia dubia/1002
Ceriodaphnia dubia/1002
Ceriodaphnia dubia/1002
Age at initiation of test
<24
<24
<24
Outfall number
001
001
001
Dates sample collected
11/12, 14/2018
2111 13 /2019
5/13,14/2019
Date test started
11/14/2018
2/13/2019
5/14/2019
Duration
7 days
7 days
7 days
b. Give toxicity test methods followed.
Manual title
EPA 821-R-02-013
EPA 821-R-02-013
EPA 821-R-02-013
Edition number and year of publication
41h Ed. 2002
41h Ed. 2002
41h Ed. 2002
Page number(s)
141-189
141-189
141-189
c. Give the sample collection method(s) used. For multiple grab samples, indicate the number of grab samples used.
24-Hour composite
X
X
X
Grab
d. Indicate where the sample was taken in relation to disinfection. (Check all that apply for each.
Before disinfection
After disinfection
After dechlorination
X
X
X
EPA Form 3510-2A (Rev. 1-99). Replaces EPA forms 7550-6 & 7550-22. Page 15 of 22

FACILITY NAME AND PERMIT NUMBER:
Lower Creek WWTP, NCO023981
PERMIT ACTION REQUESTED:
Major Modification
RIVER BASIN:
Catawba
Test number: 001 Test number: 002 Test number: 003
e. Describe the point in the treatment process at which the sample was collected.
Sample was collected:
Final effluent
Final effluent
Final effluent
f. For each test, include whether the test was intended to assess chronic toxicity, acute toxicity, or both
Chronic toxicity
X
X
X
Acute toxicity
g. Provide the type of test performed.
Static
Static -renewal
X
X
X
Flow -through
h. Source of dilution water. If laboratory water, specify type; if receiving water, specify source.
Laboratory water
Surface Water 48 hardness
Surface Water 48 hardness
Surface Water 48
hardness
Receiving water
i. Type of dilution water. If salt water, specify "natural' or type of artificial sea salts or brine used.
Fresh water
X
X
X
Salt water
j. Give the percentage effluent used for all concentrations in the test series.
44
44
44
k. Parameters measured during the test. (State whether parameter meets test method specifications)
pH
7.6 (yes)
7.6 (yes)
7.7 (yes)
Salinity
Temperature
25.0 (yes)
24.8 (yes)
24.9 (yes)
Ammonia
Dissolved oxygen
8.2 (yes)
7.9 (yes)
8.5 (yes)
I. Test Results.
Acute:
Percent survival in 100%
effluent
%
%
%
LC5o
95% C.I.
%
%
o/
0
Control percent survival
%
%
EPA Form 3510-2A (Rev. 1-99). Replaces EPA forms 7550-6 & 7550-22. Page 16 of 22

FACILITY NAME AND PERMIT NUMBER:
PERMIT ACTION REQUESTED:
RIVER BASIN:
Lower Creek WWTP, NCO023981
Major Modification
Catawba
Chronic: Test number: 001 Test number: 002
Test number: 003
NOEC
%
%
%
IC25
%
%
%
Control percent survival
100 %
100 %
100 %
Other (describe)
Pass
Pass
Pass
m. Quality Control/Quality Assurance.
Is reference toxicant data available?
Yes
Yes
Yes
Was reference toxicant test within
Yes
Yes
Yes
acceptable bounds?
What date was reference toxicant test
run (MM/DD/YYYY)?
11 /05l2018
02/08/2019
05/03l2019
Other (describe)
E.3. Toxicity Reduction Evaluation. Is the treatment works involved in a Toxicity Reduction Evaluation?
❑ Yes X❑ No If yes, describe:
EA. Summary of Submitted Biomonitoring Test Information. If you have submitted biomonitoring test information, or information regarding the
cause of toxicity, within the past four and one-half years, provide the dates the information was submitted to the permitting authority and a summary
of the results.
Date submitted: / / (MM/DD/YYYY)
Summary of results: (see instructions)
END OF PART E.
REFER TO THE APPLICATION OVERVIEW (PAGE 1) TO DETERMINE WHICH OTHER PARTS
OF FORM 2A YOU MUST COMPLETE.
EPA Form 3510-2A (Rev. 1-99). Replaces EPA forms 7550-6 & 7550-22. Page 17 of 22

FACILITY NAME AND PERMIT NUMBER:
PERMIT ACTION REQUESTED:
RIVER BASIN:
Lower Creek WWTP. NCO023981
Major Modification
Catawba
SUPPLEMENTAL APPLICATION INFORMATION
PART F.INDUSTRIAL USER DISCHARGES AND RCRA/CERCLA WASTES
All treatment works receiving discharges from significant industrial users or which receive RCRA,CERCLA, or other remedial wastes must
complete part F.
GENERAL INFORMATION:
F.1. Pretreatment program. Does the treatment works have, or is subject ot, an approved pretreatment program?
X❑ Yes ❑ No
F.2. Number of Significant Industrial Users (SIUs) and Categorical Industrial Users (CIUs). Provide the number of each of the following types of
industrial users that discharge to the treatment works.
a. Number of non -categorical SIUs. 1
b. Number of CIUs.
SIGNIFICANT INDUSTRIAL USER INFORMATION:
Supply the following information for each SIU. If more than one SIU discharges to the treatment works, copy questions F.3 through F.8 and
provide the information requested for each SIU.
F.3. Significant Industrial User Information. Provide the name and address of each SIU discharging to the treatment works. Submit additional pages
as necessary.
Name: Stallergenes Greer Laboratories
Mailing Address: PO Box 800
Lenoir, NC 28645
F.4. Industrial Processes. Describe all the industrial processes that affect or contribute to the SIU's discharge.
Biotechnology pharmaceutical facility* manufacture and distribute protein extracts: vials
F.5. Principal Product(s) and Raw Material(s). Describe all of the principal processes and raw materials that affect or contribute to the SIU's
discharge.
Principal product(s): Allergenic extracts and associated intermediator dilution vials empty vials
Raw material(s): Acetone (closed loop system) ether allergen source materials (e.g. pollens)
F.6. Flow Rate.
a. Process wastewater flow rate. Indicate the average daily volume of process wastewater discharge into the collection system in gallons per
day (gpd) and whether the discharge is continuous or intermittent.
5,300 gpd X continuous or intermittent)
b. Non -process wastewater flow rate. Indicate the average daily volume of non -process wastewater flow discharged into the collection system
in gallons per day (gpd) and whether the discharge is continuous or intermittent.
4,900 gpd (X continuous or intermittent)
F.7. Pretreatment Standards. Indicate whether the SIU is subject to the following:
a. Local limits X❑ Yes ❑ No
b. Categorical pretreatment standards X❑ Yes ❑ No
If subject to categorical pretreatment standards, which category and subcategory?
40CFR439.27 B (pharmaceutical manufacturing extraction products)
EPA Form 3510-2A (Rev. 1-99). Replaces EPA forms 7550-6 & 7550-22. Page 18 of 22

FACILITY NAME AND PERMIT NUMBER:
PERMIT ACTION REQUESTED:
RIVER BASIN:
Lower Creek WWTP, NCO023981
Major Modification
Catawba
F.8. Problems at the Treatment Works Attributed to Waste Discharge by the SIU. Has the SIU caused or contributed to any problems (e.g.,
upsets, interference) at the treatment works in the past three years?
❑ Yes X❑ No If yes, describe each episode.
RCRA HAZARDOUS WASTE RECEIVED BY TRUCK, RAIL, OR DEDICATED PIPELINE:
F.9. RCRA Waste. Does the treatment works receive or has it in the past three years received RCRA hazardous waste by truck, rail or dedicated pipe?
❑ Yes X ❑ No (go to F.12)
F.10. Waste transport Method by which RCRA waste is received (check all that apply):
❑ Truck ❑ Rail ❑ Dedicated Pipe
FA 1. Waste Description. Give EPA hazardous waste number and amount (volume or mass, specify units).
EPA Hazardous Waste Number Amount Units
CERCLA (SUPERFUND) WASTEWATER, RCRA REMEDIATION/CORRECTIVE ACTION
WASTEWATER, AND OTHER REMEDIAL ACTIVITY WASTEWATER:
F.12. Remediation Waste. Does the treatment works currently (or has it been notified that it will) receive waste from remedial activities?
❑ Yes (complete F.13 through F.15.) X ❑ No
F.13. Waste Origin. Describe the site and type of facility at which the CERCLA/RCRA/or other remedial waste originates (or is excepted to origniate in
the next five years).
F.14. Pollutants. List the hazardous constituents that are received (or are expected to be received). Include data on volume and concentration, if
known. (Attach additional sheets if necessary.)
F.15. Waste Treatment
a. Is this waste treated (or will be treated) prior to entering the treatment works?
❑ Yes ❑ No
If yes, describe the treatment (provide information about the removal efficiency):
b. Is the discharge (or will the discharge be) continuous or intermittent?
❑ Continuous ❑ Intermittent If intermittent, describe discharge schedule.
END OF PART F.
REFER TO THE APPLICATION OVERVIEW (PAGE 1) TO DETERMINE WHICH OTHER PARTS
OF FORM 2A YOU MUST COMPLETE
EPA Form 3510-2A (Rev. 1-99). Replaces EPA forms 7550-6 & 7550-22. Page 19 of 22

FACILITY NAME AND PERMIT NUMBER:
PERMIT ACTION REQUESTED:
RIVER BASIN:
Lower Creek WWTP, NCO023981
Major Modification
Catawba
SUPPLEMENTAL APPLICATION INFORMATION
PART G. COMBINED SEWER SYSTEMS
If the treatment works has a combined sewer system, complete Part G.
G.1. System Map. Provide a map indicating the following: (may be included with Basic Application Information)
a. All CSO discharge points.
b. Sensitive use areas potentially affected by CSOs (e.g., beaches, drinking water supplies, shellfish beds, sensitive aquatic ecosystems, and
outstanding natural resource waters).
C. Waters that support threatened and endangered species potentially affected by CSOs.
G.2. System Diagram. Provide a diagram, either in the map provided in G.1 or on a separate drawing, of the combined sewer collection system that
includes the following information.
a. Location of major sewer trunk lines, both combined and separate sanitary.
b. Locations of points where separate sanitary sewers feed into the combined sewer system.
C. Locations of in -line and off-line storage structures.
d. Locations of flow -regulating devices.
e. Locations of pump stations.
CSO OUTFALLS:
Complete questions G.3 through GA once for each CSO discharge point.
G.3. Description of Outfall.
a. Outfall number
b. Location
(City or town, if applicable) (Zip Code)
(County) (State)
(Latitude) (Longitude)
C. Distance from shore (if applicable) ff
d. Depth below surface (if applicable) ft
e. Which of the following were monitored during the last year for this CSO?
❑ Rainfall ❑ CSO pollutant concentrations ❑ CSO frequency
❑ CSO flow volume ❑ Receiving water quality
f. How many storm events were monitored during the last year?
GA. CSO Events.
a. Give the number of CSO events in the last year.
events (❑ actual or ❑ approx.)
b. Give the average duration per CSO event.
hours (❑ actual or ❑ approx.)
EPA Form 3510-2A (Rev. 1-99). Replaces EPA forms 7550-6 & 7550-22. Page 20 of 22

F
LITY NAME AND PERMIT NUMBER: PERMIT ACTION REQUESTED: RIVER BASIN:
Lower Creek WWTP, NCO02398 Major Modification Catawba
C. Give the average volume per CSO event.
million gallons (❑ actual or ❑ approx.)
d. Give the minimum rainfall that caused a CSO event in the last year
Inches of rainfall
G.5. Description of Receiving Waters.
a. Name of receiving water:
b. Name of watershed/river/stream system:
United State Soil Conservation Service 14-digit watershed code (if known):
C. Name of State Management/River Basin:
United States Geological Survey 8-digit hydrologic cataloging unit code (if known):
G.6. CSO Operations.
Describe any known water quality impacts on the receiving water caused by this CSO (e.g., permanent or intermittent beach closings, permanent or
intermittent shell fish bed closings, fish kills, fish advisories, other recreational loss, or violation of any applicable State water quality standard).
END OF PART G.
REFER TO THE APPLICATION OVERVIEW (PAGE 1) TO DETERMINE WHICH OTHER PARTS
OF FORM 2A YOU MUST COMPLETE.
EPA Form 3510-2A (Rev. 1-99). Replaces EPA forms 7550-6 & 7550-22. Page 21 of 22

FACILITY NAME AND PERMIT NUMBER:
PERMIT ACTION REQUESTED:
RIVER BASIN:
Lower Creek WWTP, NCO023981
Major Modification
Catawba
PART E. TOXICITY TESTING DATA
POTWs meeting one or more of the following criteria must provide the results of whole effluent toxicity tests for acute or chronic toxicity for each of the
facility's discharge points: 1) POTWs with a design flow rate greater than or equal to 1.0 mgd; 2) POTWs with a pretreatment program (or those that are
required to have one under 40 CFR Part 403); or 3) POTWs required by the permitting authority to submit data for these parameters.
• At a minimum, these results must include quarterly testing for a 12-month period within the past 1 year using multiple species (minimum of two
species), or the results from four tests performed at least annually in the four and one-half years prior to the application, provided the results
show no appreciable toxicity, and testing for acute and/or chronic toxicity, depending on the range of receiving water dilution. Do not include
information on combined sewer overflows in this section. All information reported must be based on data collected through analysis conducted
using 40 CFR Part 136 methods. In addition, this data must comply with QA/QC requirements of 40 CFR Part 136 and other appropriate QA/QC
requirements for standard methods for analytes not addressed by 40 CFR Part 136.
• In addition, submit the results of any other whole effluent toxicity tests from the past four and one-half years. If a whole effluent toxicity test
conducted during the past four and one-half years revealed toxicity, provide any information on the cause of the toxicity or any results of a
toxicity reduction evaluation, if one was conducted.
• If you have already submitted any of the information requested in Part E, you need not submit it again. Rather, provide the information
requested in question EA for previously submitted information. If EPA methods were not used, report the reasons for using alternate methods.
If test summaries are available that contain all of the information requested below, they may be submitted in place of Part E.
If no biomonitoring data is required, do not complete Part E. Refer to the Application Overview for directions on which other sections of the form to
complete.
E.I. Required Tests.
Indicate the number of whole effluent toxicity tests conducted in the past four and one-half years.
22E] chronic ❑ acute
E.2. Individual Test Data. Complete the following chart for each whole effluent toxicity test conducted in the last four and one-half years. Allow one
column per test (where each species constitutes a test). Copy this page if more than three tests are being reported.
2"d species testing for permit renewal Test number: 004 Test number: 005 Test number: 006
a. Test information.
Test Species & test method number
Fathead Minnow/1000 (2nd
Fathead Minnow/1000 (2nd
Fathead Minnow/1000
species testing)
species testing)
(2nd species testing)
Age at initiation of test
<24
<24
<24
Outfall number
001
001
001
Dates sample collected
8/13,16,17/2018
11/12,14,15/2018
2/11,13,14/2019
Date test started
8/17//2018
11/15/2018
2/14/2019
Duration
7 days
7 days
7 days
b. Give toxicity test methods followed.
Manual title
EPA 821-R-02-013
EPA 821-R-02-013
EPA 821-R-02-013
Edition number and year of publication
4th Ed. 2002
41h Ed. 2002
4th Ed. 2002
Page number(s)
141-189
141-189
141-189
c. Give the sample collection method(s) used. For multiple grab samples, indicate the number of grab samples used.
24-Hour composite
X
X
X
Grab
d. Indicate where the sample was taken in relation to disinfection. (Check all that apply for each.
Before disinfection
After disinfection
After dechlorination
X
X
X
NPDES FORM 2A Additional Information

FACILITY NAME AND PERMIT NUMBER:
Lower Creek WWTP, NCO023981
PERMIT ACTION REQUESTED:
Renewal
RIVER BASIN:
Catawba
2"d species testing for permit renewal Test number: 004 Test number: 005 Test number: 006
e. Describe the point in the treatment process at which the sample was collected.
Sample was collected:
Final effluent
Final effluent
Final effluent
f. For each test, include whether the test was intended to assess chronic toxicity, acute toxicity, or both
Chronic toxicity
X
X
X
Acute toxicity
g. Provide the type of test performed.
Static
Static -renewal
X
X
X
Flow -through
h. Source of dilution water. If laboratory water, specify type; if receiving water, specify source.
Laboratory water
Surface Water 48 hardness
Surface Water 48 hardness
Surface Water 48
hardness
Receiving water
i. Type of dilution water. If salt water, specify "natural' or type of artificial sea salts or brine used.
Fresh water
X
X
X
Salt water
j. Give the percentage effluent used for all concentrations in the test series.
11,22,44,88,100
11,22,44,88,100 �11�,22,44,�88,100
k. Parameters measured during the test. (State whether parameter meets test method specifications)
pH
6.4 (yes)
7.0 (yes)
7.2 (yes)
Salinity
Temperature
25.0 (yes)
25.1 (yes)
25.1 (yes)
Ammonia
Dissolved oxygen
6.9 (yes)
6.8 (yes)
7.1 (yes)
I. Test Results.
Acute:
Percent survival in 100%
effluent
%
%
%
LC50
95% C.I.
%
%
%
Control percent survival
%
Other (describe)
NPDES FORM 2A Additional Information

FACILITY NAME AND PERMIT NUMBER:
Lower Creek WWTP, NCO023981
PERMIT ACTION REQUESTED:
Major Modification
RIVER BASIN:
Catawba
Chronic: 2"d Species for permit renewal
NOEC
100 %
100 %
100 %
IC25
>100 %
>100 %
>100 %
Control percent survival
97.5 %
97.5 %
97.5 %
Other (describe) Chv
>100 %
>100 %
>100 %
m. Quality Control/Quality Assurance.
Is reference toxicant data available?
Yes
Yes
Yes
Was reference toxicant test within
acceptable bounds?
Yes
Yes
Yes
What date was reference toxicant test
run (MM/DD/YYW)?
08/14/2018
11/06,11/13/2018
02/06 , 02/13/2019
Other (describe)
E.3. Toxicity Reduction Evaluation. Is the treatment works involved in a Toxicity Reduction Evaluation?
❑ Yes X0 No If yes, describe:
EA. Summary of Submitted Biomonitoring Test Information. If you have submitted biomonitoring test information, or information regarding the
cause of toxicity, within the past four and one-half years, provide the dates the information was submitted to the permitting authority and a summary
of the results.
Date submitted: / / (MM/DD/YYYY)
Summary of results: (see instructions)
NPDES FORM 2A Additional Information

E T
environmental, Inc.
P.O. Box 16414, Greenville, SC 29606
[phone] . FAX [phone]
Craftsman Court, Greer, SC 29650
WATER EFFECT RATIO STUDY
City of Lenoir Lower Creek WWTP
NPDES Permit #NC0023981
Metal: Silver
Issued: February 2024
Amended 5/20/24
Lenoir Lower WER Study -Ag
Page 1 of 112
ETT Environmental, Inc.; 2/24

SUMMARY OF RESULTS
The results of the Water Effect Ratio modify the silver limits as follows;
Average Silver Limit
Revised Limit Using WER: 7.7 ug/L
Maximum Silver Limit
Revised Limit Using WER: 7.7 ug/L
EPA or state regulators may adjust the limits based on "what is needed", derived from
historical reported values for silver in site effluent.
Lenoir Lower WER Study -Ag
Page 2 of 112
ETT Environmental, Inc.; 2/24

1.0 INTRODUCTION
The City of Lenoir Lower Creek Wastewater Treatment Plant (WWTP) discharges effluent to Lower
Creek southwest of the town. ETT Environmental has been retained to conduct a Water Effect Ratio for
the facility to determine if proposed silver limits for the effluent discharge are unnecessarily
overprotective of aquatic life. This is to be accomplished through the calculation of a water effect ratio
(WER), comparing the acute effects of silver upon surrogate aquatic test organisms (the water flea
Ceriodaphnia dubia and the Fathead Minnow) living in laboratory dilution water to the acute effects of
silver to the same test species in simulated downstream receiving water.
The Lower Creek WWTP discharges effluent to Lower Creek under NPDES permit # NC 0023981.
At sites with very low metal limits, a permittee may conduct a site -specific study to determine if the
permit limit for silver should be modified to account for the unique characteristics of the receiving stream.
This is done by determining a Water Effect Ratio (WER), which is multiplied against the national water
quality criterion to calculate a site -specific criterion. Methodology for determining a WER is provided in
the Interim Guidance on Determination and Use of Water -Effect Ratios for Metals (EPA-823-B-94-001).
This report presents the results of three rounds of WER primary test determinations using acute tests with
the invertebrate Ceriodaphnia dubia and a single round of WER secondary test determinations using
acute tests with the vertebrate Pimephales promelas (Fathead Minnow). Using the Interim Guidance, a
Final WER is determined and the site specific criterion is calculated.
Lenoir Lower WER Study -Ag ETT Environmental, Inc.; 2/24
Page 3 of 112

2.0 METHODS
2.1 Overview
As delineated in the EPA Interim Guidance, a minimum of three rounds of side -by -side tests with the
primary test organism (Ceriodaphnia dubia) are required. Each round includes a 48 Hour acute definitive
test in which silver is spiked into laboratory dilution water (13% DMW - 50 mg/L hardness) alongside a
test where silver is spiked into simulated downstream water. A 48 Hour LCso is calculated for each test,
and a WER is determined based upon the ratio of the LCso in simulated downstream water divided by the
LCso in laboratory dilution water. A final WER (fWER) is determined based upon all three individual
WER values. A WER is also determined for a secondary species, which in this case is the Fathead
Minnow - Pimephales promelas. Acute definitive tests (48 Hour) with the secondary species also are
conducted as acute tests, with the endpoint being an LCso.
2.2 Simulated Downstream Water
Simulated downstream water was prepared using proportional flow at the time of sampling.
2.3 Measured Concentrations
All calculations were based upon measured concentrations of silver in the laboratory water and
downstream water. In acute tests with Ceriodaphnia dubia and Pimephales promelas measured
concentrations of total silver were conducted for each test concentration at test initiation and at test
termination. Dissolved silver also was measured at test initiation and test termination.
2.4 Laboratory Water
Due to the relatively low hardness of the receiving stream and effluent, 13% DMW (diluted mineral water
at —50 mg/L hardness) was used as the laboratory water into which silver was spiked.
Lenoir Lower WER Study -Ag ETT Environmental, Inc.; 2/24
Page 4 of 112

2.5 Determination of Final Water Effect Ratio
Type I WERs most accurately simulate design -flow conditions, so these values are used directly in
determination of the EWER.
Type II WERs are not representative of the design flow conditions, but can be used in two ways. First, a
Type II WER can be considered a conservative estimate of the WER at design flow conditions, since the
WER will typically be lower for higher stream flows. Type II WERs are also used to calculate the highest
WER (hWER) that would provide adequate protection under design flow conditions. The hWER
incorporates the highest concentration of metal in the effluent (HOME) which will not cause the site
specific criterion to be exceeded downstream. The HCME is then used to predict the hWER at design
flow conditions. The HCME is calculated as follows;
HCME= [CCC x WER x (eFLOW+uFLOW)] - [(uCONC)(uFLOW)]
eFLOW
where; CCC= criterion continuous concentration
WER= the Type II WER which is experimentally determined
eFLOW= effluent flow at time of sampling
uFLOW= upstream flow at time of sampling
uCONC= silver concentration upstream at time of sampling
The hWER is calculated as follows;
hWER= (HCME) x (eFLOWdf) + (uCONCdf) x (uFLOWdf)
(CCC) x (eFLOWdf+ uFLOWdf)
where df indicates the value under design flow conditions.
In this study two of the primary WERs were Type I WERs and the third was a Type II WER. According
to the Interim Guidance, with this combination, the final water effect ratio (EWER) is the lowest of a) the
geometric mean of the Type I WERs, or b) the lowest hWER. Method 1 (determining WERs for areas in
or near plumes), was used.
Lenoir Lower WER Study -Ag
Page 5 of 112
ETT Environmental, Inc.; 2/24

3.0 RESULTS
3.1 Determination of Type 1 vs. Type 2 Conditions
Type I tests are tests conducted when downstream flow is <2 times the design flow. Type II tests
are tests conducted when downstream flow is >2 times the design flow.
The flows for this study are summarized as follows;
Upstream flow
Effluent Flow
Design 11.75 mgd
9.23 mgd
Round 1 47.70 mgd
2.248 mgd
Round 2 36.37 mgd
1.985 mgd
Round 3 9.93 mgd
2.074 mgd
3.2 Water Effect Ratios for Each Round of Tests
Downstream Flow
21.0 mgd
49.95 mgd Type 2
3 8.3 6 mgd Type 1
12.00 mgd Type 1
The experimentally derived (hardness adjusted) WERs for total recoverable silver for acute
testing with Ceriodaphnia dubia and Pimephales promelas are summarized as follows;
Total Ag Dis. Ag
Date Species WER WER
Round 1.
3/22/23
primary
6.8920
NA
Round 2
5/24/23
primary
6.8693
7.1290
Round 3
10/25/23
primary
6.4613
NA
Round 4
6/28/23
secondary
4.8931
NA
Because the WER for the secondary test was within a factor of three of the low Type I value in the
primary test, the secondary test is considered to confirm the primary test results.
Lenoir Lower WER Study -Ag
Page 6 of 112
ETT Environmental, Inc.; 2/24

3.3 Calculation of Highest Concentration of Metal in Effluent (HOME) Values
Calculations of HCME values are provided in Table 1. HCME (total recoverable) values ranged
from 30.7000 ug/L in Round 3 to 90.1215 ug/L in Round 1.
3.4 Calculation of hWER Values
Calculations of hWER values are provided in Table 1. hWER (total recoverable) values ranged
from 16.4536 ug/L in Round 3 to 67.3738 ug/L in Round 1.
3.5 Calculation of Final Water Effect Ratio (fWER)
As noted above, when two rounds of testing are Type I, and a single round is Type II, the Interim
Guidance requires that the fWER be calculated as the lowest of either 1) the geometric mean of
the Type I WERs or 2) the lowest WER. The results are summarized as follows;
Geometric Mean Lowest
Tyne 1 WER fWER
Total Rec. Cu 6.5155 16.4536
The WER values for acute tests with fathead minnows were not used in the calculations.
Lenoir Lower WER Study -Ag
Page 7 of 112
ETT Environmental, Inc.; 2/24

3.6 Calculation of Site Specific Average Limit for Silver
The site specific criterion (S) is adjusted by multiplying the hardness adjusted CCC times the
f WER.
Site Specific CCC = S = [(ccc) x (fWER)]
[0.6129A x 6.5155B ] = 3.9930 ug/L
A: recalculated CCC (ug/L) at site hardness (34.7 mg/L)
B: geometric mean of Type I WERs
The site specific CCC (S) is then adjusted using EPA procedures and incorporating the
effluent IWC as follows;
Proposed effluent average limit = 7.7 µg/L (using Total Recoverable Silver MER)
Lenoir Lower WER Study -Ag
Page 8 of 112
ETT Environmental, Inc.; 2/24

3.7 Calculation of Site Specific Maximum Limit for Silver
The site specific criterion (S) is adjusted by multiplying the hardness adjusted CMC times the
fWER.
Site Specific CMC = S = [(cmc) x (fWER)]
[0.6129A x 6.5155B ] = 3.9930 ug/L
A: recalculated CMC (ug/L) at site hardness (34.7 mg/L)
B: geometric mean of Type I WERs
The site specific CMC (S) is then adjusted using EPA procedures and incorporating the
effluent IWC as follows;
Proposed effluent average limit = 7.7 µg/L (using Total Recoverable Silver fWER)
Lenoir Lower WER Study -Ag
Page 9 of 112
ETT Environmental, Inc.; 2/24

TABLE 1.
DERIVATION OF TOTAL SILVER fWERS WITH HARDNESS ADJUSTMENT
Facility: Lenoir Lower Creek T-Ag
WER #
1: 3/22123
2: 05/24/23
3: 10/25/23
3: 6/28123
nCMC= e(1.72[ln(hardness)]-6.59) Upstream Design Flow: 11.75 mgd 56.00%
adj EC50=e(1.72[In(site water hard-In(lab water hard)]) Effluent Design Flow: 9.231 mgd 44.00%
Upstream Design Conc.: 0 ppb
WER
Type
Lab Water
Hardness EC50 Ad' EC50
Site Water
Hardness EC50 Ad' EC50
Original Hard. Adj.
WER WER
CMC @ CCC @
site hard site hard
Upstream Effluent
Flow Flow
Upstream Effluent
Hardness Hardness
HCME hWER
2
48.0000
0.57021
0.2922
32.5401
2.0137
NA
3.5316
6.8920
0.58851
0.5885
47.7000
2.2480
32.0000
44.0000
90.1215
67.3738
1
50.0000
1.12201
0.4633
29.8965
3.1823
NA
2.8363
6.8693
0.5087
0.5087
36.3700
1.9850
30.0000
28.0000
67.5209
58.3974
1
50.0000
0.80541
0.5366
39.4869
3.4674
NA
4.3052
6.4613
0.82091
0.8209
9.9300
2.0740
37.5000
49.0000
30.7000
16.4536
fish
48.0000
4.93171
3.1291
36.8440
15.3109
NA
3.1046
4.8931
0.72871
0.7287
93.3800
2.2210
36.7000
42.9000
153.4804
92.6667
Final WER fWER = geometricmean ofT e1 WERs = =
Water Quality Criteria - A - Adjusted for WER
Assigned Effluent Hardness: 34.7 m /L
CCC(total)= Sccc= 3.993 = [e (1.72[ln(hardness)]-6.59)]*fWER
CMC = Seme 3.993 = e 1.72 In hardness -6.59 *EWER
Geometric Mean Calculation for Type 1 WERs - Total Silver
Date
WER nat log (In-mean)2
Type 1 #1
6.8693 1.9271 0.0009
Type 1 #2
6.4613 1.8658 0.0009
mean 1.8964
sum 0.0019
s= 0.0433
SE= 0.0306
A= 1.8742
Adjusted Geometric Mean: 6.5155
Calculation of Total Recoverable Effluent Limits
Formulas
Ct (acute) = ScMc * CF * [1+(Kp * (TSSA(1+�)) * 1000000)]
Ct (chronic) = Sccc CF * [1+(Kp * (TSSA(1+�)) * 1000000)]
Sccc/cmc CF I Cd
Effluent Limit
Ct
Effluent Limit
Ad'. for IWC
Chronic mo. average)
3.993
0.85
1 3.3942
3.4
7.7
Acute(daily max
3.993
0.85
1 3.3942
3.4
7.7
u /L
u /L
Page 10 of 112

ET
environmental, Inc.
P.O. Box 16414, Greenville, SC 29606
APPENDIX A
[phone] . FAX [phone]
Craftsman Court, Greer, SC 29650
WATER EFFECT RATIO STUDY
City of Lenoir, N.C.
Lower Creek WWTP
Primary Species - Round 1
Metal: Silver
March 2023
Lower Creek WWTP - WER 1 Ag ETT Environmental; 3/23
Page 11 of 112

TABLE OF CONTENTS
1.0 INTRODUCTION
2.0 METHODS
2.1 Experimental Design
2.2 Laboratory Dilution Water
2.3 Upstream and Effluent Sample Collection
2.4 Chemical Analyses
2.5 Preparation of Test Solutions
2.6 Test Organisms
kjll� oI.Y�1 rlI1F.y
3.1 Laboratory Water
3.2 Simulated Downstream Water
3.3 Upstream Waters
4.0 CALCULATION OF WATER EFFECT RATIO
5.0 DISCUSSION
LIST OF APPENDICES
Appendix Al. Reference Toxicant Quality Control Chart for Ceriodaphnia dubia
Appendix A2. Survival Data for Acute Definitive Tests
Appendix A3. Measured Concentrations of Total Recoverable Silver in Test Solutions
Appendix A4. Water Chemistry Measurements for Acute Definitive Tests
Appendix A5. Chain of Custody Records
Appendix A6. Statistical Analysis Results
Lower Creek WWTP - WER 1 Ag
Page 12 of 112
ETT Environmental; 3/23

1.0 INTRODUCTION
The City of Lenoir, N.C. Lower Creek wastewater treatment plant (WWTP) discharges effluent into
LowerCreek under NPDES Permit NC0023981. ETT Environmental has been retained to conduct a "site
specific study" to determine if permitted silver limits for each effluent discharge are unnecessarily
overprotective of aquatic life. This is to be accomplished through the calculation of a water effect ratio
(WER), comparing the acute effects of silver upon the surrogate aquatic test organism Ceriodaphnia
dubia living in laboratory dilution water to the acute effects of silver to the same test species in simulated
downstream receiving water. The study used the methodology provided in the Interim Guidance on
Determination and Use of Water -Effect Ratios for Metals (EPA-823-B-94-001).
On March 21, 2023, Lower Creek WWTP personnel collected a grab effluent water sample. Acute
toxicity tests for the Water Effect Ratio study were initiated on March 22, 2023.
Laboratory Location:
NCDNR Certification #
Study Director:
Study Scientist:
Study Technicians:
Study Dates:
ETT Environmental, Inc.
4 Craftsman Court
Greer, SC 29650
;1767►.1
Robert W. Kelley, Ph.D.
Amy McMahon
Jennifer Christian
March 22-24, 2023
Lower Creek WWTP - WER 1 Ag
Page 13 of 112
ETT Environmental; 3/23

2.0 METHODS
2.1
2.2
Experimental Design
The design of the study involved spiking silver into test solutions and assessing the acute
toxicity of the test solutions with 48 Hour Acute Definitive tests using the surrogate test
organism Ceriodaphnia dubia. The two test solutions assessed were 1) laboratory dilution
water, and 2) simulated downstream water at measured conditions on the day of sampling
(4.5% effluent). Acute toxicity tests were set according to U.S. EPA protocols (EPA
821-R-02-012 Method 2002), modified according to the following parameters;
Test type:
Temperature:
Light:
Test Chambers:
Test Solution Volume:
Renewal of Test Solutions:
Test Organism Age:
# Neonates/Cup:
# Replicates/Concentration:
Feeding Regime:
Aeration:
Dilution Factor:
Test Duration:
Endpoints:
Laboratory Dilution Water
Acute Static
250C fl
100 ft.-candles; 16 hr light/8 hr dark
30 mL plastic cups
25 mL
None
< 24 hr
5
4
None
None
0.7
48 Hours
Survival
The laboratory dilution water used in all tests was diluted mineral water (DMW). In this
first round of tests the DMW was prepared at a hardness of 48.0 mg/L. This dilution
water was prepared by adding Perrier water to ultra -pure water to obtain the desired final
hardness. The procedure for the preparation of this water may be found in the EPA
manual Short Term Methods for Estimating the Chronic Toxicity of Effluents and
Receiving Waters to Freshwater Organisms (EPA 82 1 -R-02-013).
* Dilution water during the period of testing was prepared as follows;
Amount Hardness Conductivity Alkalini pH
20 L 48.0 mg/L 114 µmhos/cm 48.1 mg/L 8.0
Lower Creek WWTP - WER 1 Ag ETT Environmental; 3/23
Page 14 of 112

2.3 Sample Collection
Sampling Locations
The effluent discharges into Lower Creek. The effluent samples were collected as
composite samples. As received the effluent had no measureable residual chlorine (<0.05
mg/L). Effluent flow in the 24 hour period preceding sample collection was 2.248 mgd.
Upstream water samples were collected as grab samples upstream from the effluent
discharge point. Upstream flow was estimated based on flow at the USGS station located
at Johns River at Arney's Store (the closest USGS station to the WWTP). This estimate
was calculated as follows. On the day of sample collection the flow at the USGS
monitoring station was 312 cfs. The 25th percentile flow at the USGS station (50 cfs) was
assumed to be the 7Q10 flow. Thus, on the day of sample collection, the Johns River
flow was 6.24 times the 7Q10 flow (312 cfs / 50 cfs). The 7Q10 upstream flow at the
discharge point of the WWTP on Lower Creek is 11.75 cfs. When the factor of 6.24 is
applied to the Lower Creek 7Q10 flow, it is thereby estimated that the upstream flow on
Gunpowder Creek on the day of sample collection was 6.24 x 11.75 cfs = 73.76 cfs (47.7
mgd)
All samples were collected in half gallon plastic jugs and preserved in coolers at 0-6°C.
Samples were transferred to an ETT courier by WWTP personnel.
2.4 Chemical Analyses
Dissolved oxygen and pH were measured in one surrogate of each test concentration at
the beginning and end of the test. Temperature was monitored in three surrogate test cups
in the incubator daily. Dissolved Oxygen and pH were measured with the use of a Orion
4 Star meter. The meter is calibrated daily.
Alkalinity, hardness, total suspended solids (TSS), total organic carbon (TOC), and
specific conductance were measured on each laboratory water and effluent sample
collected.
Lower Creek WWTP - WER 1 Ag
Page 15 of 112
ETT Environmental; 3/23

Total recoverable silver was measured on each test solution at the beginning and end of
the test. Dissolved silver also was measured for each test concentration at the beginning
and end of the test. Silver analyses were conducted by ETT Environmental of Greer, SC
using Standard Methods 181h Edition Method 3111B (flame atomic absorption), and
concentrated to achieve a detection limit of 10 ug/L (or lower with concentration).
2.5 Preparation of Test Solutions
2.5.1 Simulated Downstream Water
Based upon the measured effluent flow (2.248 mgd) and the estimated upstream flow
(47.7 mgd) , a simulated downstream sample was prepared using 4.5% effluent and 95.5%
upstream water.
2.5.2 Silver Spiking
Silver was spiked as silver nitrate (Ag NO3) into laboratory water and the simulated
downstream water. Prior to spiking the total recoverable silver in each effluent sample
was measured. Each day a batch of simulated downstream water was prepared. A
microliter syringe was used to add the correct volumes of the stock solution to each
simulated effluent or control concentration to achieve the desired nominal concentration
of silver.
2.6 Test Organisms
The test organism used for this study was the daphnid Ceriodaphnia dubia. Test
organisms were neonates of less than 24 hours in age which were obtained from
individual cultures at ETT Environmental, Inc. These cultures are set weekly with
reproduction of the first three broods tracked for all culture organisms. Only neonates
from broods of eight or larger, produced by culture trays demonstrating less than 10%
mortality and greater than a mean of 15 young per female (3 broods) are used for testing.
Culture sensitivity is monitored through the use of semi-monthly reference toxicant
testing. Voucher specimens from the culture are set aside on a monthly basis and
taxonomically verified by a staff macroinvertebrate taxonomist. Culture organisms are
subject to the same light, temperature, and feeding regimes as used for testing.
Lower Creek WWTP - WER 1 Ag
Page 16 of 112
ETT Environmental; 3/23

3.0 RESULTS
3.1 Laboratory Water
3.1.1 Acute Toxicity Testing Results
The acute definitive test with Ceriodaphnia dubia in laboratory water spiked with silver
showed a 48 Hour LCso of 0.5702 ug/L Total Recoverable Silver. A 48 Hour LCso of
Dissolved Silver could not be determined because concentrations were too low for
accurate measurement. Due to the pattern of the data, the values were calculated using the
logistic method. The survival data at each concentration are summarized as follows;
Nominal Concentration
of Total Recoverable Ag
Measured Concentration
of Total Recoverable Ag
and (Dissolved Ag)
48 Hour
Mortality
0 ug/L
<1.0 ug/L (<1.0)
0%
0.25 ug/L
6.9 ug/L
0%
0.35 ug/L
0.38 ug/L
0%
0.50 ug/L
0.69 ug/L
100%
0.71 ug/L
0.95 ug/L
100%
1.02 ug/L
1.60 ug/L
100%
Survival data for the test may be found in Appendix A2. Results of measured
concentrations of total recoverable and dissolved silver are provided in Appendix A3.
Statistical analysis results are found in Appendix A6.
3.1.2 Chemical Anal
The pH in the spiked dilution water test ranged from a minimum of 8.0 to a maximum of
8.5. Dissolved oxygen was generally at the saturation point in all treatments throughout
the test.
Lower Creek WWTP - WER 1 Ag
Page 17 of 112
ETT Environmental; 3/23

3.2 Simulated Downstream Water
3.2.1 Acute Toxicity Testing Results
The acute definitive test with Ceriodaphnia dubia in downstream water spiked with silver
showed a 48 Hour LCso of 2.0137 ug/L Total Recoverable Silver and a 48 Hour LCso
of 1.7783 ug/L of Dissolved Silver. Due to the pattern of the data, the value was
calculated using the logistic method. The survival data at each concentration are
summarized as follows;
Nominal Concentration
of Total Recoverable
Ag
Measured Concentration
of Total Recoverable
Ag and (Dissolved Ag)
48 Hour
Mortality
0 ug/L
<5.0 ug/L (<5.0)
0%
1.02 ug/L
0.7 ug/L (0.45)
0%
1.02 ug/L
1.13 ug/L (0.8)
5%
1.43 ug/L
1.4 ug/L (1.4)
20%
2.04 ug/L
3.15 ug/L (2.40)
85%
2.92 ug/L
3.24 ug/L (3.20)
100%
Measured concentrations were generally higher than nominal concentrations. A
significant suppression in survival was noted at a nominal concentration of 2.04 ug/L of
total silver.
Survival data for the test may be found in Appendix A2. Results of measured
concentrations of total recoverable and dissolved silver are provided in Appendix A3.
Statistical analysis results are found in Appendix A6.
Lower Creek WWTP - WER 1 Ag
Page 18 of 112
ETT Environmental; 3/23

3.2.2 Chemical Anal
The pH in the simulated downstream water ranged from a minimum of 7.3 to a maximum
of 8.3. Dissolved oxygen was generally near the saturation point in all treatments
throughout the test. Other water chemistry parameters are summarized as follows;
Parameter
Effluent
Total Recoverable Silver (ug/L)
<5.0
Dissolved Silver (ug/L)
<5.0
Alkalinity (mg/L)
21.9
Conductivity (umhos/cm)
315
Hardness (mg/L)
44.0
Total Organic Carbon (mg/L)
5.2
Total Suspended Solids (mg/L)
6.8
It may be seen that the effluent water was characterized by low alkalinity, hardness, TOC
and TSS.
3.3 Upstream Waters
Water quality parameters measured on upstream waters are provided in the following table;
Parameter
Result
Total Recoverable Silver (µg/L)
<5.0
Dissolved Silver (µg/L)
<5.0
Total Organic Carbon (mg/L)
<1.0
Alkalinity (mg/L)
29.8
Hardness (mg/L)
32
Conductivity (µmhos/cm)
87
Total Suspended Solids (mg/L)
3.0
Lower Creek WWTP - WER 1 Ag
Page 19 of 112
ETT Environmental; 3/23

4.0 CALCULATION OF WATER EFFECT RATIO
As noted in the results section, acute testing indicated an LCso of 0.5702 ug/L of total recoverable
silver in laboratory dilution water and an LCso of 2.01372 ug/L of total recoverable silver in 4.5%
Lower Creek WWTP downstream water. The laboratory dilution water LCso values must be
adjusted to downstream water hardness in order to calculate the Water Effect Ratio, using the
EPA formula, as follows;
LCso x (downstream hardness/laboratory water hardness)1.72
T-Cu: 0.5702 ug/L x (32.54/48)0.9422 = 0.2922 ug/L
Dis-Cu: NA (values too low to obtain measured concentrations)
The Water Effect Ratio can thus be calculated as follows;
Water Effect Ratio (WER) = LCso in Effluent = 2.0137 ug/L = 6.8920
(Total Recoverable Silver) LCso in Lab Water 0.2922 ug/L
A final water effect ratio (FWER) will be calculated using the individual WERs from three
rounds of testing.
Lower Creek WWTP - WER 1 Ag
Page 20 of 112
ETT Environmental; 3/23

ROUND 1 -APPENDIX Al
Reference Toxicant Quality Control Chart
Ceriodaphnia dubia
See Round 3 Appendix C.
Lower Creek WWTP - WER 1 Ag
Page 21 of 112
ETT Environmental; 3/23

Lower Creek WWTP - WER 1 Ag
ROUND 1 -APPENDIX A2
Survival Data for Acute Definitive Tests
ETT Environmental; 3/23
Page 22 of 112

Nominal
ea®®
®aa
ea®a
WER 48 Hour Acute Toxici Test
Facility: DMW
Metal: Ag
Sample ID:
Start Date: 03/22/23 Time: 3:30 By: AM
End Date: 03/24/23 Time: 2:30 By: AM
Eff. Log #: EEFU stream Loa #:
TEST ORGANISMS
Test Organism: Cerioda hnia dubia
for Ceriodaphnia dubia Source: l-L 3-16-23, M-R 3-
S-X 3-10; A-F 3-10 corr. by
Date Removed: 03/26/23 5/10/24
Between 1700 hrs 2200 hrs
for fathead minnows or mysids
I 3/21/23 corr by RWK 4/10/24 I
Source:
Tem erature 24-26 C. Light 16 hr It / 8 hr dk; 50-100 ft-candles
Laboratory Water DMW / SSF A 50 m hardness
Downstream Water Preoaration
effluent
volume
volume
Date:
Test Solution Preparation:
Date: 03/22/23
Prep By
W
RK
Metal Salt: A NO3
Stock. Soln:
Nominal Conc,
mL Stock Soln.
Volume Prepared
0 u
0.00 mL
500 mL
0.17 u
3 uL mL
500 mL
0.25 u
4 uL mL
500 mL
0.35 u
6 uL mL
500 mL
u
mL
mL
u
mL
mL
u
mL
mL
u
mL
mL
Water Chemistry Time: Analyst.
D.O.(m )
H
DMW Start
Final
m
S.U.
m L
S.U.
Downstream Start
Final
m
S.U.
m
S.U.
eam Start
m
s.u.
rs!
uent Start
m
S.U.
Test solution volume: 25 mt.. Test vessels 1 oz, plastic cups. Transfer volume 0.05 mL.
Page 23 of 112
Test Method: per EPA Interim Guidance

Nominal I I Initial #
Conc.
I Rep.
organ)
0.0
u(B
A
5
5
c
5
D
5
fl c,"
A
5
24 hr
Mortality
48 hr
0
0
0
0
i
TEST ORGANISMS
5
5
Test Organism: Cerioda hnia dubia
kD
5
5
for Ceriodaphnia dubia Source: S-X 3-10; A-F 3-10
Date Removed: 03/21/23
Between 1700 hrs 2200 hrs
5
5
5
5
0.70
u
A
B
5
5
for fathead minnows or mysids
Source:
C
5
5
� TS 15 I I s I Tamner t—')d_'JFi r I.iaht 1.S hr It I R hr dk, SO —MO ft_enndles
1.02
A
5
5
DMW / SSF50 m hardness
u
B
5
5
stream Water Pre aration
C
5
5
ELaboratoryWater
uent
ream
volume
Prep. Date:
D
5
5
volume
Prep. By:
o©tea
ea�a
ea�a
.
®ate®
ear®
N_n=
�■®
nm�®
®®tea
e®tea
®®tea
e®tea
Test Solution Preparation:
Date: 02/04/22
Prep By
AM
Metal Salt: 1�1 ��
Stock. Solm I2.72 m
Nominal Conc.
mL Stock Soln.
Volume Prepared
0
ugfL
0.000
mL
500 mL
0.50
ug/L
0.039
mL
500 mL
0.70
ug/L
0.055
mL
500 mL
1.02
It L
0.080
mL
5CO mL
1.43
u
0.113
mL
500 mL
2.02
u
0.161
tnL
500 mL
2.92
u
0.230
mL
500 mL
4.17
u L
0.328
mL
500 mL
Water Chemist
Time:
02:30 PM
Analyst: ,z
D.O.(m )
pH
DMW
Start
Final
7.9
m
9.0 S.U.
8.6 mgiL
3.5 S.U.
Downstream
Start
Final
9.0
m
7.5 S.U.
m
S. U.
U stream
Start
9.8
m
7.4 S.U.
Effluent
Start
9.4
m
7.n S.U.
Test solution volume: 25 mL. Test vessels t oz. plastic cups. Transfer volume 0.05 mL.
Page 24 of 112
Test Method: per EPA Interim Guidance

Mortality
24 hr 48 hr
ear®
ear®
e®tea
®®tea
-- �e®tea
e®tea
ea�a
e©tea
.
e©tea
,e®tea
e®tea
saw®
WER 48 Hour Acute Toxicity
Test
Facility:
Lenoir Lower
Metal: Ag
Sample ID:
Start Date:
03/22/23 Time: 02:30 PM
By: JZ
End Date:
03/24/23 Time: 2:30
By: JC
Eff. Log #:
64422 711111FU stream Log
#: 64423
TEST ORGANISMS
Test Or anism: Cerioda hnia dubia
for Ceriodaphnia dubia Source: S-X 3-10;A-F 3-10
Date Removed: 03/21/23
Between 1700 hrs 2200 hrs
for fathead minnows or mysids
Source:
Temperature 24-26 C. Uaht 16 hr It 18 hr dk; 50-100 ft-candles
DMW / SSF 50 m hardness
nstream Water Pre aration
[LaboratoryWater
%fluent
stream
4.5%
volume 180 mL
Pre . Date: 3-22-23
95.5%
volume 3820 mL
Prep. By:
Test Solution Preparation:
Date: 03/22/23
Prep By
RWK
Metal Salt:
A NO3
Stock. Soln:
6.35 TWL
Nominal Conc.
mL Stock Soln.
Volume Prepared
0
u
0.000
mL
500 mL
0.70
u
0.055
mL
500 mL
1.02
u
0.080
mL
500 mL
1.43
u
0.113
mL
500 mL
2.02
u
0.161
mL
500 mL
2.92
u
0.230
mL
500 mL
4.17
u
0.328
mL
500 mL
5.96
u
0.469
mL
500 mL
Water Chemistry
Time:
2:30
Analyst: 1Z
D.O.(m )
PH
DMW
Start
Final
7.9
m L
8.0 S.U.
8.6 m L
8.5 S.U.
Downstream
Start
Final
9.0
m
7,5 S.U.
8.5 m
8.3 S.u.
U stream
Start
9.8
MWL
La S.U.
Effluent
Start
9.4
ma/L
7.0 s.u.
Page 25 of 112

ROUND 1 - APPENDIX A3
Measured Concentrations of Total Recoverable Silver in Test Solutions
Lower Creek WWTP - WER 1 Ag
ETT Environmental; 3/23
Page 26 of 112

Measured Total Recoverable and Dissolved Silver
Lenoir Lower Creek - Primary Species Site Specific Study
March 2023
Samole: Spiked Dilution Water (Diluted DMWInitial Date: 3/22/23
Nominal
Total Ag
Measured Total Recoverable Silver (µg/L)
Initial Day 1 Day 2 Day 3 Day 4 Day 5 Day 6 Day 7 Mean
% of
Nominal
0
<5.0
<5.0
<5.0
<5.0
0.35
0.38
0.38
109%
0.501
0.69
0.69
138%
0.71
0.95
0.95
134%
1.02
1.60
1.60
157%
1.43
2.04
1.60
1.90
1.75
86%
Samole: Simulated Downstream Initial Date: 3/22/23
Nominal
Total Ag
Measured Total Recoverable Silver (µg/L)
Initial Day 1 Day 2 Day 3 Day 4 Day 5 Day 6 Day 7 Mean
% of
Nominal
0.00
0.60
0.50
6.00
0.70
0.70
0.70
100%
1.02
0.85
1.40
1.13
lll%
1.431
1.80
1.00
1.40
98%
2.04
3.15
3.15
154%
2.92
3.24
3.24
111 %
Dissolve values for DMW were too low to obtain measured concentrations
11 _ _
Measured Dis. Ag (µg/L)
Initial Day 2 Mean
Measured Dis. Ag (µg/L)
Initial Day 2 Mean
%
Dissolved
0.60
0.80
0.70
0.20
0.70
0.45
64%
0.80
0.80
71%
2.40
0.40
1.40
100%
2.40
2.40
76%
4.601
1.80
3.20
99%
Page 27 of 112

ROUND 1 - APPENDIX A4
Water Chemistry Measurements for Acute Definitive Tests
Lower Creek WWTP - WER 1 Ag
See Appendix A2
ETT Environmental; 3/23
Page 28 of 112

Lower Creek WWTP - WER 1 Ag
ROUND 1 - APPENDIX A5
Chain of Custody Documentation
ETT Environmental; 3/23
Page 29 of 112

ETT
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PO Box 16414, Greenville, SC 29606-7414
[phone], [phone]
Shipping Address: 4 Craftsman Ct, Greer, SC 29650
www.ettla6.arg
CHAIN OF CUSTODY RECORD
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1 Gd
.2
COMPOSITE SAMPLING PROCEDURES TEAIPERATURE MONITORING PROCEDURES HOLD TIME PROCEDURES
Composite samples must be collected over a 24 hour period. Sample temperature during collection and transport must be between For toxicity testing the sample must first be used within 36 hours
Time Proportional: 1 sample each flour for 24 hours. Equal volui 0.0 and 6.0 *C. Samples must not be frozen. Use water ice in sealed bags. of sample collection (completion of composite sample).
or at minimum 1 sample every 4 hours over 24 hours. Sample may not be used after 72 hours from sample collection.
Flow Proportional: As per instructions in NPDES permit.
Page 30 of 112

Lower Creek WWTP - WER 1 Ag
ROUND I - APPENDIX A6
Statistical Analysis Results
ETT Environmental; 3/23
Page 31 of 112

LOGISTIC MODEL
Survival
Test: DMW
Date: 3l22/2023
T A9
gamma 0
1 E-05
alpha
-0.244
beta
-75 sury
0
100
test conc
0.25
100
0.38
100
0.69
0
0.95
0
1.6
0
LC50
0.57016427
a
0
predicted
num denominator y
100 1 100
0.25 1 100
denom 0.38 1.00000182 99.99982
0.69 500.537068 0.199785
0.95 16672487.4 6E-06
1.6 3.9464E+14 2.5E-13
IC25 2 50 actual mean
predicted reproduction
10011 _
90
Page 32 of 112

LOGISTIC MODEL
Survival
Test Lenoir Lower
Date: 3/22/2023
T Ag
gamma 0
1E-05
alpha
0.304
beta
-8.8
sury
0
100
test cone
0.7
100
1.13
95
1.4
80
3.15
15
3.24
0
LC50
2.01372425
0
0
predicted
num denominator y
100 1 100
0.7 1.017626757 98.26786
denom 1.13 1.109908212 90.09754
1.4 1.249256377 80.04762
3.15 6.528590349 15.31724
3.24 7.157039675 13.97226
IC25 2 50
90 `
80
70
60
50
40
101
�0 0.5 1 1.5 2
a actual mean
actual mean
predicted reproduction
2.5 3
predicted
reproduction
3.5 1
Page 33 of 112

LOGISTIC MODEL
Survival
Test: Lenoir Lower
Date: 31=023
Dis Ag
gamma 0
1 E-05
alpha
0.25
beta
-13.3
sury
0
100
testconc
0.45
100
0.8
95
1.4
80
2.4
15
3.2
0
LC50
1.77827941
0
predicted
num denominator y
100 1 100
0.45 1.000357179 99.96429
denom 0.8 1.00991305 99.01843
1.4 1.25120219 79.92313
2.4 6.650869995 15.03563
3.2 30.76980759 3.249939
IC25 2 50
"0 0.5 1 1.5 2 2.5 3
® predicted
reproduction
actual mean
predicted reproduction
.E actual mean
i
3.5
Page 34 of 112

ET
environmental, Inc.
P.O. Box 16414, Greenville, SC 29606
APPENDIX B
[phone] . FAX [phone]
Craftsman Court, Greer, SC 29650
WATER EFFECT RATIO STUDY
City of Lenoir, N.C.
Lower Creek WWTP
Primary Species - Round 2
Metal: Silver
May 2023
Lower Creek WWTP - WER 2 Ag ETT Environmental; 5/23
Page 35 of 112

TABLE OF CONTENTS
1.0 INTRODUCTION
2.0 METHODS
2.1 Experimental Design
2.2 Laboratory Dilution Water
2.3 Upstream and Effluent Sample Collection
2.4 Chemical Analyses
2.5 Preparation of Test Solutions
2.6 Test Organisms
kjll� oI.Y�1 rlI1F.y
3.1 Laboratory Water
3.2 Simulated Downstream Water
3.3 Upstream Waters
4.0 CALCULATION OF WATER EFFECT RATIO
5.0 DISCUSSION
LIST OF APPENDICES
Appendix B 1. Reference Toxicant Quality Control Chart for Ceriodaphnia dubia
Appendix B2. Survival Data for Acute Definitive Tests
Appendix B3. Measured Concentrations of Total Recoverable Silver in Test Solutions
Appendix B4. Water Chemistry Measurements for Acute Definitive Tests
Appendix B5. Chain of Custody Records
Appendix B6. Statistical Analysis Results
Lower Creek WWTP - WER 2 Ag
Page 36 of 112
ETT Environmental; 5/23

1.0 INTRODUCTION
The City of Lenoir, N.C. Lower Creek wastewater treatment plant (WWTP) discharges effluent into
LowerCreek under NPDES Permit NC0023981. ETT Environmental has been retained to conduct a "site
specific study" to determine if permitted silver limits for each effluent discharge are unnecessarily
overprotective of aquatic life. This is to be accomplished through the calculation of a water effect ratio
(WER), comparing the acute effects of silver upon the surrogate aquatic test organism Ceriodaphnia
dubia living in laboratory dilution water to the acute effects of silver to the same test species in simulated
downstream receiving water. The study used the methodology provided in the Interim Guidance on
Determination and Use of Water -Effect Ratios for Metals (EPA-823-B-94-001).
On May 23, 2023, Lower Creek WWTP personnel collected a grab effluent water sample. Acute toxicity
tests for the Water Effect Ratio study were initiated on May 24, 2023.
Laboratory Location:
NCDNR Certification #
Study Director:
Study Scientist:
Study Technicians:
Study Dates:
ETT Environmental, Inc.
4 Craftsman Court
Greer, SC 29650
;1767►.1
Robert W. Kelley, Ph.D.
Amy McMahon
Jennifer Christian
May 24-26, 2023
Lower Creek WWTP - WER 2 Ag
Page 37 of 112
ETT Environmental; 5/23

2.0 METHODS
2.1
2.2
Experimental Design
The design of the study involved spiking silver into test solutions and assessing the acute
toxicity of the test solutions with 48 Hour Acute Definitive tests using the surrogate test
organism Ceriodaphnia dubia. The two test solutions assessed were 1) laboratory dilution
water, and 2) simulated downstream water at measured conditions on the day of sampling
(5.2% effluent). Acute toxicity tests were set according to U.S. EPA protocols (EPA
821-R-02-012 Method 2002), modified according to the following parameters;
Test type:
Temperature:
Light:
Test Chambers:
Test Solution Volume:
Renewal of Test Solutions:
Test Organism Age:
# Neonates/Cup:
# Replicates/Concentration:
Feeding Regime:
Aeration:
Dilution Factor:
Test Duration:
Endpoints:
Laboratory Dilution Water
Acute Static
250C fl
100 ft.-candles; 16 hr light/8 hr dark
30 mL plastic cups
25 mL
None
< 24 hr
5
4
None
None
0.7
48 Hours
Survival
The laboratory dilution water used in all tests was diluted mineral water (DMW). In this
first round of tests the DMW was prepared at a hardness of 50.0 mg/L. This dilution
water was prepared by adding Perrier water to ultra -pure water to obtain the desired final
hardness. The procedure for the preparation of this water may be found in the EPA
manual Short Term Methods for Estimating the Chronic Toxicity of Effluents and
Receiving Waters to Freshwater Organisms (EPA 82 1 -R-02-013).
* Dilution water during the period of testing was prepared as follows;
Amount Hardness Conductivity Alkalini pH
20 L 50.0 mg/L 116 µmhos/cm 49.4 mg/L 7.9
Lower Creek WWTP - WER 2 Ag ETT Environmental; 5/23
Page 38 of 112

2.3 Sample Collection
Sampling Locations
The effluent discharges into Lower Creek. The effluent samples were collected as
composite samples. As received the effluent had no measureable residual chlorine (<0.05
mg/L). Effluent flow in the 24 hour period preceding sample collection was 1.985 mgd.
Upstream water samples were collected as grab samples upstream from the effluent
discharge point. Upstream flow was estimated based on flow at the USGS station located
at Johns River at Arney's Store (the closest USGS station to the WWTP). This estimate
was calculated as follows. On the day of sample collection the flow at the USGS
monitoring station was 238 cfs. The 25th percentile flow at the USGS station (50 cfs) was
assumed to be the 7Q10 flow. Thus, on the day of sample collection, the Johns River
flow was 4.76 times the 7Q10 flow (238 cfs / 50 cfs). The 7Q10 upstream flow at the
discharge point of the WWTP on Lower Creek is 11.75 cfs. When the factor of 4.76 is
applied to the Lower Creek 7Q10 flow, it is thereby estimated that the upstream flow on
Gunpowder Creek on the day of sample collection was 4.76 x 11.75 cfs = 56.26 cfs
(36.37 mgd)
All samples were collected in half gallon plastic jugs and preserved in coolers at 0-6°C.
Samples were transferred to an ETT courier by WWTP personnel.
2.4 Chemical Analyses
Dissolved oxygen and pH were measured in one surrogate of each test concentration at
the beginning and end of the test. Temperature was monitored in three surrogate test cups
in the incubator daily. Dissolved Oxygen and pH were measured with the use of a Orion
4 Star meter. The meter is calibrated daily.
Alkalinity, hardness, total suspended solids (TSS), total organic carbon (TOC), and
specific conductance were measured on each laboratory water and effluent sample
collected.
Lower Creek WWTP - WER 2 Ag
Page 39 of 112
ETT Environmental; 5/23

Total recoverable silver was measured on each test solution at the beginning and end of
the test. Dissolved silver also was measured for each test concentration at the beginning
and end of the test. Silver analyses were conducted by ETT Environmental of Greer, SC
using Standard Methods 181h Edition Method 3111B (flame atomic absorption), and
concentrated to achieve a detection limit of 10 ug/L (or lower with concentration).
2.5 Preparation of Test Solutions
2.5.1 Simulated Downstream Water
Based upon the measured effluent flow (1.985 mgd) and the estimated upstream flow
(36.37 mgd) , a simulated downstream sample was prepared using 5.2% effluent and
94.8% upstream water.
2.5.2 Silver Spiking
Silver was spiked as silver nitrate (Ag NO3) into laboratory water and the simulated
downstream water. Prior to spiking the total recoverable silver in each effluent sample
was measured. Each day a batch of simulated downstream water was prepared. A
microliter syringe was used to add the correct volumes of the stock solution to each
simulated effluent or control concentration to achieve the desired nominal concentration
of silver.
2.6 Test Organisms
The test organism used for this study was the daphnid Ceriodaphnia dubia. Test
organisms were neonates of less than 24 hours in age which were obtained from
individual cultures at ETT Environmental, Inc. These cultures are set weekly with
reproduction of the first three broods tracked for all culture organisms. Only neonates
from broods of eight or larger, produced by culture trays demonstrating less than 10%
mortality and greater than a mean of 15 young per female (3 broods) are used for testing.
Culture sensitivity is monitored through the use of semi-monthly reference toxicant
testing. Voucher specimens from the culture are set aside on a monthly basis and
taxonomically verified by a staff macroinvertebrate taxonomist. Culture organisms are
subject to the same light, temperature, and feeding regimes as used for testing.
Lower Creek WWTP - WER 2 Ag
Page 40 of 112
ETT Environmental; 5/23

3.0 RESULTS
3.1 Laboratory Water
3.1.1 Acute Toxicity Testing Results
The acute definitive test with Ceriodaphnia dubia in laboratory water spiked with silver
showed a 48 Hour LC5o of 1.1220 ug/L Total Recoverable Silver and 1.0233 ug/L
Dissolved SIlver. Due to the pattern of the data, the values were calculated using the
logistic method. The survival data at each concentration are summarized as follows;
Nominal Concentration
of Total Recoverable Ag
Measured Concentration
of Total Recoverable Ag
and (Dissolved Ag)
48 Hour
Mortality
0 ug/L
<1.0 ug/L (<1.0)
0%
0.35 ug/L
0.30 ug/L
0%
0.50 ug/L
0%
0.71 ug/L
0.60 ug/L
0%
1.02 ug/L
1.05 ug/L
80%
1.43 ug/L
1.50 ug/L
100%
Survival data for the test may be found in Appendix B2. Results of measured
concentrations of total recoverable and dissolved silver are provided in Appendix B3.
Statistical analysis results are found in Appendix B6.
3.1.2 Chemical Analyses
The pH in the spiked dilution water test ranged from a minimum of 7.9 to a maximum of
8.3. Dissolved oxygen was generally at the saturation point in all treatments throughout
the test.
Lower Creek WWTP - WER 2 Ag
Page 41 of 112
ETT Environmental; 5/23

3.2 Simulated Downstream Water
3.2.1 Acute Toxicity Testing Results
The acute definitive test with Ceriodaphnia dubia in downstream water spiked with silver
showed a 48 Hour LC50 of 3.1823 ug/L Total Recoverable Silver and a 48 Hour LC50
of 3.0120 ug/L of Dissolved Silver. Due to the pattern of the data, the value was
calculated using the logistic method. The survival data at each concentration are
summarized as follows;
Nominal Concentration
of Total Recoverable
Ag
Measured Concentration
of Total Recoverable
Ag and (Dissolved Ag)
48 Hour
Mortality
0 ug/L
<1.0 ug/L (<1.0)
0%
1.4 ug/L
1.55 ug/L (1.2)
0%
2.0 ug/L
2.4 ug/L (2.05)
0%
2.9 ug/L
2.75 ug/L (2.2)
15%
4.2 ug/L
2.9 ug/L (2.8)
25%
6.0 ug/L
5.2 ug/L (4.8)
100%
Measured concentrations were generally higher than nominal concentrations. A
significant suppression in survival was noted at a nominal concentration of 4.2 ug/L of
total silver.
Survival data for the test may be found in Appendix B2. Results of measured
concentrations of total recoverable and dissolved silver are provided in Appendix B3.
Statistical analysis results are found in Appendix B6.
Lower Creek WWTP - WER 2 Ag
Page 42 of 112
ETT Environmental; 5/23

3.2.2 Chemical Anal
The pH in the simulated downstream water ranged from a minimum of 7.3 to a maximum
of 8.2. Dissolved oxygen was generally near the saturation point in all treatments
throughout the test. Other water chemistry parameters are summarized as follows;
Parameter
Effluent
Total Recoverable Silver (ug/L)
<5.0
Dissolved Silver (ug/L)
<5.0
Alkalinity (mg/L)
52.6
Conductivity (umhos/cm)
307
Hardness (mg/L)
28.0
Total Organic Carbon (mg/L)
<5.0
Total Suspended Solids (mg/L)
<5.0
It may be seen that the effluent water was characterized by low alkalinity, hardness, TOC
and TSS.
3.3 Upstream Waters
Water quality parameters measured on upstream waters are provided in the following table;
Parameter
Result
Total Recoverable Silver (µg/L)
<5.0
Dissolved Silver (µg/L)
<5.0
Total Organic Carbon (mg/L)
<5.0
Alkalinity (mg/L)
31.9
Hardness (mg/L)
30
Conductivity (µmhos/cm)
91
Total Suspended Solids (mg/L)
<5.0
Lower Creek WWTP - WER 2 Ag
Page 43 of 112
ETT Environmental; 5/23

4.0 CALCULATION OF WATER EFFECT RATIO
As noted in the results section, acute testing indicated an LC50 of 1.1220 ug/L of total
recoverable silver in laboratory dilution water and an LC50 of 3.1823 ug/L of total recoverable
silver in 4.5% Lower Creek WWTP downstream water. The laboratory dilution water LC50
values must be adjusted to downstream water hardness in order to calculate the Water Effect
Ratio, using the EPA formula, as follows;
LC50 x (downstream hardness/laboratory water hardness)1.71
T-Cu: 1.1220 ug/L x (29.90/50)0.122 = 0.4633 ug/L
Dis-Cu: 1.0233 ug/L x (29.90/50)0.122 = 0.4225 ug/L
The Water Effect Ratio can thus be calculated as follows;
Water Effect Ratio (WER)
(Total Recoverable Silver)
Water Effect Ratio (WER)
(Dissolved Silver)
= LC50 in Effluent
LC50 in Lab Water
3.1823 ug/L = 6.8693
0.4633 ug/L
LC50 in Effluent = 3.0120 ug/L = 7.1290
50 in Lab Water 5 ug/L
A final water effect ratio (FWER) will be calculated using the individual WERs from three
rounds of testing.
Lower Creek WWTP - WER 2 Ag
Page 44 of 112
ETT Environmental; 5/23

ROUND 2 -APPENDIX B1
Reference Toxicant Quality Control Chart
Ceriodaphnia dubia
See Round 3 Appendix C.
Lower Creek WWTP - WER 2 Ag
Page 45 of 112
ETT Environmental; 5/23

Lower Creek WWTP - WER 2 Ag
ROUND 2 -APPENDIX B2
Survival Data for Acute Definitive Tests
ETT Environmental; 5/23
Page 46 of 112

Notni"al
Mortality
®tea
e®tea
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o_--
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WER 48 Hour Acute Toxicity Test
Facility: DMW
Metal: Ag
Sample ID:
Start Date: 05/24/23 Time: 11:30 By: AM
End Date: 05/26/23 Time: 11:45 By: JC
Eff. Log #: U stream Log#:
TEST ORGANISMS
st Organism: Cerioda hnia dubia
Ceriodaphnia dubia Source: G-L 5-I I, M-R 5-11
Date Removed: 05/23/22 05/23/23 corr. by RWK 5/10/24
Between 1700 hrs. 2200 hrs
fathead minnows or mysids
Source:
nperature 24-26 C. Light 16 hr It / 8 hr dk; 50-100 ft-candles
iboratory Water DMW / SSF @ 50 mgfL hardness
€wnstream Water Preparation
effluent volume Prep. Date:
upstream volume Prep. By:
Test Solution Preparation:
Date: 05/23/23
Prep By
AM
Metal Salt: A NO3
Stock. Soln; 6.35 m L
Nominai Conc.
mL Stock Soln.
Volume Prepared
0.17 U
0.01 mL
500 mL
0.25 u
0.02 mL
500 mL
0.35 u
0.03 mL
500 mL
0.5 u
0.04 mL
500 mL
0.7 u
0.06 ML
500 mL
1.02 U
0.08 mL
500 mL
1.43 u
0.11 mL
500 mL
u
mL
mL
Water Chemistry Time: Analyst:
D.O.(m
H
DMW Start
Final
7.9 m L
7.9 S.U.
8.0 m
8.3 S.U.
Downstream Start
Final
m
S.U.
m
S.U.
U stream Start
m
S.U.
Effluent Start
m
S.u.
Test solution volume: 25 mL. Test vessels 1 oz. plastic cups. Transfer volume 0.05 mL.
Page 47 of 112
Test Method: per EPA Interim Guidance

24 hr Mortality 48 hr
■NEE
TEST ORGANISMS
Test Organism: Cerioda hnia dubi77
for Ceriodaphnia dubia Source: G-L 5-I 1, M-R 5- ,,
Date Removed: 05/23/23
Between 1700 hrs 2200 hrs
for fathead minnows or mysids
Source:
Temperature 24-26 C. Light 16 hr It 18 hr dk; 50-100 fit -candles
Laborato Water DMW / SSF 50 m hardness
Downstream Water Preparation
% effluent
% u stream
5.2%
volume 208
Prep. Dater 05/24/23
94.8%
voltune 3792
1 Pre . By: AM
Test Solution Preparation:
Date: 05/23/23
Prep By
AM
Meta' salt: A NO3
[=St.k.n: 6.35 m
Nominal Conc.
mL Stock Soln,
Volume Prepared
0.7 U
0.06 ML
500 mL
1.02 u
0.08 mL
500 mL
1.43 u
0.11 JUL
500 mL
2.04 u
0.16 mL
500 mL
2.92 u
0.23 mL
500 mL
4.17 u
0.33 mL
500 mL
5.96 ugil,
0.47 mL
500 mL
u
mL
mL
Water Chemistry Time: Aonlv.w
D.O.(m )
PH
DMW Start
Final
7.9 m L
7.9 S.U.
8.0 m L
8.3 SAL
Downstream Start
Final
8.2 m L
7.3 S.U.
8.3 m L
9.2 SAL
Upstream Start
9.2 m
7.3 S.U.
Effluent Start
7.9 MWL
7.3 S.u.
Test solution volume: 25 mL Test vessels 7 oz. plastic cups. Transfer volume 0.05 mL. Test Method: per EPA Interim Guidance
Page 48 of 112

ROUND 2 - APPENDIX B3
Measured Concentrations of Total Recoverable Silver in Test Solutions
Lower Creek WWTP - WER 2 Ag
ETT Environmental; 5/23
Page 49 of 112

Measured Total Recoverable and Dissolved Silver
Lenoir Lower Creek - Primary Species Site Specific Study
May 2023
Samole: Spiked Dilution Water (Diluted DMWInitial Date: 5/24/23
Nominal
Total Ag
Measured Total Recoverable Silver (µg/L)
Initial Day 1 Day 2 Day 3 Day 4 Day 5 Day 6 Day 7 Mean
% of
Nominal
0
<1.0
<1.0
0.25
0.40
0.20
0.30
120%
0.351
0.50
0.71
0.60
1
1
1
1 0.60
8500
1.02
1.60
0.50
1.05
103%
1.40
1.90
1.10
1.50
1070YO
Samole: Simulated Downstream Initial Date: 5/24/23
Nominal
Total Ag
Measured Total Recoverable Silver (µg/L)
Initial Day 1 Day 2 Day 3 Day 4 Day 5 Day 6 Day 7 Mean
% of
Nominal
0.00
<1.0
<1.0
<1.0
1.40
1.90
1.20
1.55
111%
2.00
2.60
2.20
2.40
120%
2.901
3.40
2.10
2.7U59
4.20
2.90
2.90
2.96.00
5.30
5.10
5.2
Measured Dis. Ag (µg/L)
Initial Day 2 Mean
%
Dissolved
<2
<2
0.90
0.90
l.so
1.80
Measured Dis. Ag (µg/L)
Initial Day 2 Mean
%
Dissolved
<l.o
<1.0
0.70
1.10
1.30
1.20
77%
2.20
1.90
2.05
85%
2.40
2.00
2.20
80%
2.90
2.70
2.80
97%
5.30
4.30
4.80
92%
Page 50 of 112

ROUND 2 - APPENDIX B4
Water Chemistry Measurements for Acute Definitive Tests
Lower Creek WWTP - WER 2 Ag
See Appendix B2
ETT Environmental; 5/23
Page 51 of 112

Lower Creek WWTP - WER 2 Ag
ROUND 2 - APPENDIX B5
Chain of Custody Documentation
ETT Environmental; 5/23
Page 52 of 112

ETT
PO Box 16414, Greenville, SC 29606-7414
[phone], (B00) 891-2325
Shipping Address: 4 Craftsman Ct, Greer, SC 29650
www.ettlah.arg
CHAIN OF CUSTODY RECORD
F6&v , /. q f(5
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Facility: Gd,,U, er--e f
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'OMPOSITE SAhlPLIArG PROCEDURES TEMPERATURE MONITORING PROCEDURES HOLD TIME PROCEDURES
,omposite samples must be collected over a 24 hour period. Sample temperature during collection and transport must be between For toxicity testing the sample must first be used within 36 hours
'ime Proportional: I sample each hour for 24 hours. Equal volu 0.0 and 6.0'C. Samples must not be frozen. Use water ice in sealed bags. of sample collection (completion of composite sample).
it at minimum I sample every 4 hours over 24 hours. Sample may not be used after 72 hours from sample collection.
:low Proportional: As per instructions in NPDES permit.
Page 53 of 112

Lower Creek WWTP - WER 2 Ag
ROUND 2 -APPENDIX B6
Statistical Analysis Results
ETT Environmental; 5/23
Page 54 of 112

LOGISTIC MODEL
Survival
Test: DMW
Date: 5/2-4 �
T Ag
gamma
0
1E-05
alpha
0.05
beta
-49
SUN
0
100
test conc
0.35
100
0.5
100
0.6
100
1.05
80
1.5
0
LC50
1.12201845
0
predicted
num denominator y
100 1 100
0.35 1 100
denom 0.5 1.000000034 100
0.6 1.00000164 99.99984
1.05 1.243722659 80.40378
1.5 483.2543605 0.20693
IC25 2 50 actual mean
Page 55 of 112

LOGISTIC MODEL
Survival
Test: DMW
Date: 5/24/2023
Dis Ag
gamma 0
1 E-05
alpha
0.01
beta
-25
sury
0
100
test conc
0.35
100
0.5
100
0.7
100
0.9
80
1.8
0
LC50
1.02329299
0
predicted
num denominator y
100 1 100
0.35 1.000008734 99.99913
denom 0.5 1.000419793 99.95804
0.7 1.01620316 98,40552
0.9 1.248096557 80.12201
1.8 461.2697026 0.216793
IC25 2 50 actual mean
predicted reproduction
1001.
90.:------------ -- . __.._......-.............. ........... ..... ..... ... ........ .___...----------- _._... ---
80 ........ _....
-
70
60-
50 _
40
30 - ---- - ..._._...._.._._..---------------- ---- - ..........
20.........__..........__._......_.._
10.. _
00 0.4 0.8 1.2 1.6 2
actual mean ® predicted
reproduction
Page 56 of 112

LOGISTIC MODEL
Survival
Test: Lenoir Lower
Date: 5/2412023
T A9
gamma 0
1 E-05
alpha
0.5
beta
-29 SUN
0
100
test cone
1.55
100
2.2
100
2.76
85
2.9
75
5.2
0
LC50
3.16227766
0
0
predicted
num denominator y
100 1 100
1.56 1.000125855 99.98742
denom 2.2 1.01036063 98.97456
2.75 1.172156406 85.31285
2.9 1.336062521 74.8468
5.2 526,3669472 0.189982
IC25 2 50
actual mean
predicted reproduction
100,
90
70
60 -_
50
40
101
00 1
3
iw actual mean
4 5
® predicted
reproduction
Ctl
Page 57 of 112

LOGISTIC MODEL
Survival
Test: Lenoir Lower
Date: 5/24/2023
Dis Ag
gamma 0
1 E-05
alpha
0.48
beta
-34
sury
0
100
test cons
1.3
100
1.9
100
2.2
85
2.8
75
4.8
0
LC50
3.01995172
0
predicted
num denominator y
100 1 100
1.3 1.000003934 99.99961
denom 1.9 1.001067562 99.89336
2.2 1.009301042 99.07847
2.8 1.327382216 75.33625
4.8 937.5492133 0.1 C6661
IC25 2 50 actual mean
predicted reproduction
m-actual mean
® predicted
reproduction
Page 58 of 112

ET
environmental, Inc.
P.O. Box 16414, Greenville, SC 29606
APPENDIX C
[phone] . FAX [phone]
Craftsman Court, Greer, SC 29650
WATER EFFECT RATIO STUDY
City of Lenoir, N.C.
Lower Creek WWTP
Primary Species - Round 3
Metal: Silver
October 2023
Lower Creek WWTP - WER 3 Ag ETT Environmental; 10/23
Page 59 of 112

TABLE OF CONTENTS
1.0 INTRODUCTION
2.0 METHODS
2.1 Experimental Design
2.2 Laboratory Dilution Water
2.3 Upstream and Effluent Sample Collection
2.4 Chemical Analyses
2.5 Preparation of Test Solutions
2.6 Test Organisms
kjll� oI.Y�1 rlI1F.y
3.1 Laboratory Water
3.2 Simulated Downstream Water
3.3 Upstream Waters
4.0 CALCULATION OF WATER EFFECT RATIO
5.0 DISCUSSION
LIST OF APPENDICES
Appendix C1. Reference Toxicant Quality Control Chart for Ceriodaphnia dubia
Appendix C2. Survival Data for Acute Definitive Tests
Appendix C3. Measured Concentrations of Total Recoverable Silver in Test Solutions
Appendix C4. Water Chemistry Measurements for Acute Definitive Tests
Appendix C5. Chain of Custody Records
Appendix C6. Statistical Analysis Results
Lower Creek WWTP - WER 3 Ag
Page 60 of 112
ETT Environmental; 10/23

1.0 INTRODUCTION
The City of Lenoir, N.C. Lower Creek wastewater treatment plant (WWTP) discharges effluent into
LowerCreek under NPDES Permit NC0023981. ETT Environmental has been retained to conduct a "site
specific study" to determine if permitted silver limits for each effluent discharge are unnecessarily
overprotective of aquatic life. This is to be accomplished through the calculation of a water effect ratio
(WER), comparing the acute effects of silver upon the surrogate aquatic test organism Ceriodaphnia
dubia living in laboratory dilution water to the acute effects of silver to the same test species in simulated
downstream receiving water. The study used the methodology provided in the Interim Guidance on
Determination and Use of Water -Effect Ratios for Metals (EPA-823-B-94-001).
On October 24, 2023, Lower Creek WWTP personnel collected a grab effluent water sample. Acute
toxicity tests for the Water Effect Ratio study were initiated on October 25, 2023.
Laboratory Location:
NCDNR Certification #
Study Director:
Study Scientist:
Study Technicians:
Study Dates:
ETT Environmental, Inc.
4 Craftsman Court
Greer, SC 29650
;1767►.1
Robert W. Kelley, Ph.D.
Amy McMahon
Jennifer Christian
October 25-27, 2023
Lower Creek WWTP - WER 3 Ag
Page 61 of 112
ETT Environmental; 10/23

2.0 METHODS
2.1
2.2
Experimental Design
The design of the study involved spiking silver into test solutions and assessing the acute
toxicity of the test solutions with 48 Hour Acute Definitive tests using the surrogate test
organism Ceriodaphnia dubia. The two test solutions assessed were 1) laboratory dilution
water, and 2) simulated downstream water at measured conditions on the day of sampling
(17.3% effluent). Acute toxicity tests were set according to U.S. EPA protocols (EPA
821-R-02-012 Method 2002), modified according to the following parameters;
Test type:
Temperature:
Light:
Test Chambers:
Test Solution Volume:
Renewal of Test Solutions:
Test Organism Age:
# Neonates/Cup:
# Replicates/Concentration:
Feeding Regime:
Aeration:
Dilution Factor:
Test Duration:
Endpoints:
Laboratory Dilution Water
Acute Static
250C fl
100 ft.-candles; 16 hr light/8 hr dark
30 mL plastic cups
25 mL
None
< 24 hr
5
4
None
None
0.7
48 Hours
Survival
The laboratory dilution water used in all tests was diluted mineral water (DMW). In this
first round of tests the DMW was prepared at a hardness of 50.0 mg/L. This dilution
water was prepared by adding Perrier water to ultra -pure water to obtain the desired final
hardness. The procedure for the preparation of this water may be found in the EPA
manual Short Term Methods for Estimating the Chronic Toxicity of Effluents and
Receiving Waters to Freshwater Organisms (EPA 82 1 -R-02-013).
* Dilution water during the period of testing was prepared as follows;
Amount Hardness Conductivity Alkalini pH
20 L 50.0 mg/L 114 µmhos/cm 48.7 mg/L 8.1
Lower Creek WWTP - WER 3 Ag ETT Environmental; 10/23
Page 62 of 112

2.3 Sample Collection
Sampling Locations
The effluent discharges into Lower Creek. The effluent samples were collected as
composite samples. As received the effluent had no measureable residual chlorine (<0.05
mg/L). Effluent flow in the 24 hour period preceding sample collection was 2.074 mgd.
Upstream water samples were collected as grab samples upstream from the effluent
discharge point. Upstream flow was estimated based on flow at the USGS station located
at Johns River at Arney's Store (the closest USGS station to the WWTP). This estimate
was calculated as follows. On the day of sample collection the flow at the USGS
monitoring station was 104 cfs. The 25th percentile flow at the USGS station (80 cfs) was
assumed to be the 7Q10 flow. Thus, on the day of sample collection, the Johns River
flow was 1.3 times the 7Q10 flow (104 cfs / 80 cfs). The 7Q10 upstream flow at the
discharge point of the WWTP on Lower Creek is 11.75 cfs. When the factor of 1.3 is
applied to the Lower Creek 7Q10 flow, it is thereby estimated that the upstream flow on
Lower Creek on the day of sample collection was 1.3 x 11.75 cfs = 15.37 cfs (9.93 mgd)
All samples were collected in half gallon plastic jugs and preserved in coolers at 0-6°C.
Samples were transferred to an ETT courier by WWTP personnel.
2.4 Chemical Analyses
Dissolved oxygen and pH were measured in one surrogate of each test concentration at
the beginning and end of the test. Temperature was monitored in three surrogate test cups
in the incubator daily. Dissolved Oxygen and pH were measured with the use of a Orion
4 Star meter. The meter is calibrated daily.
Alkalinity, hardness, total suspended solids (TSS), total organic carbon (TOC), and
specific conductance were measured on each laboratory water and effluent sample
collected.
Lower Creek WWTP - WER 3 Ag
Page 63 of 112
ETT Environmental; 10/23

Total recoverable silver was measured on each test solution at the beginning and end of
the test. Dissolved silver also was measured for each test concentration at the beginning
and end of the test. Silver analyses were conducted by ETT Environmental of Greer, SC
using Standard Methods 18th Edition Method 3111B (flame atomic absorption), and
concentrated to achieve a detection limit of 10 ug/L (or lower with concentration).
2.5 Preparation of Test Solutions
2.5.1 Simulated Downstream Water
Based upon the measured effluent flow (2.074 mgd) and the estimated upstream flow
(9.93 mgd) , a simulated downstream sample was prepared using 17.3% effluent and
82.7% upstream water.
2.5.2 Silver Spiking
Silver was spiked as silver nitrate (Ag NO3) into laboratory water and the simulated
downstream water. Prior to spiking the total recoverable silver in each effluent sample
was measured. Each day a batch of simulated downstream water was prepared. A
microliter syringe was used to add the correct volumes of the stock solution to each
simulated effluent or control concentration to achieve the desired nominal concentration
of silver.
2.6 Test Organisms
The test organism used for this study was the daphnid Ceriodaphnia dubia. Test
organisms were neonates of less than 24 hours in age which were obtained from
individual cultures at ETT Environmental, Inc. These cultures are set weekly with
reproduction of the first three broods tracked for all culture organisms. Only neonates
from broods of eight or larger, produced by culture trays demonstrating less than 10%
mortality and greater than a mean of 15 young per female (3 broods) are used for testing.
Culture sensitivity is monitored through the use of semi-monthly reference toxicant
testing. Voucher specimens from the culture are set aside on a monthly basis and
taxonomically verified by a staff macroinvertebrate taxonomist. Culture organisms are
subject to the same light, temperature, and feeding regimes as used for testing.
Lower Creek WWTP - WER 3 Ag
Page 64 of 112
ETT Environmental; 10/23

3.0 RESULTS
3.1 Laboratory Water
3.1.1 Acute Toxicity Testing Results
The acute definitive test with Ceriodaphnia dubia in laboratory water spiked with silver
showed a 48 Hour LC5o of 0.8054 ug/L Total Recoverable Silver and 0.5754 ug/L
Dissolved Silver. Due to the pattern of the data, the values were calculated using the
logistic method. The survival data at each concentration are summarized as follows;
Nominal Concentration
of Total Recoverable Ag
Measured Concentration
of Total Recoverable Ag
and (Dissolved Ag)
48 Hour
Mortality
0 ug/L
<1.0 ug/L (<1.0)
0%
1.0 ug/L
0.40 ug/L
0%
1.4 ug/L
0.65 ug/L
30%
2.0 ug/L
1.05 ug/L
85%
2.9 ug/L
1.65 ug/L
100%
4.2 ug/L
2.45 ug/L
100%
Survival data for the test may be found in Appendix C2. Results of measured
concentrations of total recoverable and dissolved silver are provided in Appendix C3.
Statistical analysis results are found in Appendix C6.
3.1.2 Chemical Analyses
The pH in the spiked dilution water test ranged from a minimum of 8.1 to a maximum of
8.3. Dissolved oxygen was generally at the saturation point in all treatments throughout
the test.
Lower Creek WWTP - WER 3 Ag
Page 65 of 112
ETT Environmental; 10/23

3.2 Simulated Downstream Water
3.2.1 Acute Toxicity Testing Results
The acute definitive test with Ceriodaphnia dubia in downstream water spiked with silver
showed a 48 Hour LC50 of 3.4674 ug/L Total Recoverable Silver. An 48 Hour LCso of
for Dissolved Silver could not be determined because the spiked silver did not stay
in solution. Due to the pattern of the data, the value was calculated using the logistic
method. The survival data at each concentration are summarized as follows;
Nominal Concentration
of Total Recoverable
Ag
Measured Concentration
of Total Recoverable
Ag and (Dissolved Ag)
48 Hour
Mortality
0 ug/L
<1.0 ug/L
0%
4.2 ug/L
2.5 ug/L
0%
6.0 ug/L
3.15 ug/L
0%
12.2 ug/L
3.7 ug/L
95%
17.4 ug/L
4.25 ug/L
100%
24.8 ug/L
4.75 ug/L
100%
Measured concentrations were generally higher than nominal concentrations. A
significant suppression in survival was noted at a measured concentration of 3.7 ug/L of
total silver.
Survival data for the test may be found in Appendix C2. Results of measured
concentrations of total recoverable and dissolved silver are provided in Appendix C3.
Statistical analysis results are found in Appendix C6.
Lower Creek WWTP - WER 3 Ag
Page 66 of 112
ETT Environmental; 10/23

3.2.2 Chemical Anal
The pH in the simulated downstream water ranged from a minimum of 7.3 to a maximum
of 8.1. Dissolved oxygen was generally near the saturation point in all treatments
throughout the test. Other water chemistry parameters are summarized as follows;
Parameter
Effluent
Total Recoverable Silver (ug/L)
<0.5
Dissolved Silver (ug/L)
<0.5
Alkalinity (mg/L)
24.4
Conductivity (umhos/cm)
39.6
Hardness (mg/L)
49.0
Total Organic Carbon (mg/L)
4.2
Total Suspended Solids (mg/L)
4.6
Typographical error. The conductivity was
396 umhos/cm; verifieed by checking the
conductivity benchsheet records.
Corr. by RWK 5/10/24
It may be seen that the effluent water was characterized by low alkalinity, hardness, TOC
and TSS.
3.3 Upstream Waters
Water quality parameters measured on upstream waters are provided in the following table;
Parameter
Result
Total Recoverable Silver (µg/L)
<0.5
Dissolved Silver (µg/L)
<0.5
Total Organic Carbon (mg/L)
<1.0
Alkalinity (mg/L)
32.1
Hardness (mg/L)
37.5
Conductivity (µmhos/cm)
90
Total Suspended Solids (mg/L)
10.7
Lower Creek WWTP - WER 3 Ag
Page 67 of 112
ETT Environmental; 10/23

4.0 CALCULATION OF WATER EFFECT RATIO
As noted in the results section, acute testing indicated an LCso of 0.8054 ug/L of total recoverable
silver in laboratory dilution water and an LCso of 3.4674 ug/L of total recoverable silver in 17.3%
Lower Creek WWTP downstream water. The laboratory dilution water LCso values must be
adjusted to downstream water hardness in order to calculate the Water Effect Ratio, using the
EPA formula, as follows;
LCso x (downstream hardness/laboratory water hardness)1.71
T-Cu: 0.8054 ug/L x (39.49/50)" = 0.5366 ug/L
Dis-Cu: 0.5754 ug/L x (39.49/50)1 72 = 0.4225 ug/L
The Water Effect Ratio can thus be calculated as follows;
Water Effect Ratio (WER)
(Total Recoverable Silver)
= LCso in Effluent
LCso in Lab Water
= 3.4674 ug/L = 6.4613
0.5366 ug/L
A final water effect ratio (FWER) will be calculated using the individual WERs from three
rounds of testing.
Lower Creek WWTP - WER 3 Ag
Page 68 of 112
ETT Environmental; 10/23

ROUND 3 -APPENDIX C1
Reference Toxicant Quality Control Chart
Ceriodaphnia dubia
Note: Original report mistakenly inserted reference toxicant data for Pimephales
promelas in this section. It has now been replaced by the correct Ceriodaphnia dubia
reference toxicant data. Corr. by RWK 5/10/24
Lower Creek WWTP - WER 3 Ag
Page 69 of 112
ETT Environmental; 10/23

ACUTE FEFTC - 2022 -23 dubia; Toxicant NaCl,. Fight to Left
2,84--------------------
2.5 --------------------
2K Za 2M 2M
243 20 1 242 242 2A2 242 241 2A2 242 21H
----------
233
a ��
226 2M 222 222 222 Am,227 229
J
22 ---- ---- — -- x
2� 2�fi
- 2m 2M 2@ 202 2� 2 2� 202 2 2oe 2m 2W 2M 2M 2W 2M 21k'
cc -
1 — — — — — — — — — — — — — — — — — — — -
co N
N
Date
N N
❑
MEAN
❑
LC56
❑
UPPER
❑
LOWER
LIGL S LGL ARE +1- 2 STD D FROM MEAN
Page 70 of 112

48 Hour Acute Toxicity Test Benchsheet
Test Method: EPA 821 R-02-012 Method 2002 Ceriodaphnia dubia
Client:
11-1-23 AD C DUBIA REF TOX
Sample ID:
NaCI Lab ID# 11-1-23 AD C DUBIA R
Start Date:
11/01/23 Time:
01:40 PM
Set By:
Ended By:
JC
JG
End Date: 11/03/23 Time: 02:15 PM
Test Vessel
Test Solution Volume
Incubator
Transfer Volume
Dilution Water
Ceriodaphnia dubia
30 mL plastic cup
25 mL
#1
0.05 mL
MHSF
Randomization pattern per SOP lNeonates from common holding vessel
Light: 50 -100 ft-c. 16 hr light / 8 hr dark
TEST ORGANISMS
for Ceriodaphnia dubia
Date Removed: 31-Oct Between: 1700 and: 2200
Pime hales promelas Source: Days old:
M sido sis Bahia Source: a s old:
Test Organisms Pre Fed by: AM Time: 11:10
MORTALITY DATA
®�Cum
lative Mortality
21 0 k 72 96
Comments:
Initial
Final
Temp
ID.O. JpH
I
I By:
Temp
D.O.
I
I By:
24.41
8.31
7.71
JJC
24.71
8.21
8.111
JG
24.4
8.31
7.71
JJC
24.71
8.41
8.411
JG
24.4
8.31
7.71
JJC
24.71
8.41
8.311
JG
24.41
8.31
7.71
JJC
24.71
8.21
8.4
JG
24.41
8.31
7.811
JC
24.71
8.41
8.411
JG
24.41
8.31
7.811
JC
24.71
8.61
8.41
JG
°C
Im /L
°C
m
48 Hour Acute Toxicity Test Statistics
Statistical Method: Spearman Karber
48 Hour LC50 = 2.28 g/L NaCl Lower Confidence Limit 2.22
Upper Confidence Limit 2.35
Page 71 of 112

Lower Creek WWTP - WER 3 Ag
ROUND 3 -APPENDIX C2
Survival Data for Acute Definitive Tests
ETT Environmental; 10/23
Page 72 of 112

Nominal
Conc.
Rep.
Initial ii
organisms
Mortality
24 hr 48 hr
0.0
ugfL
A
5
0
B
5
0
C
5
0
n}`
D
5
0
0.2
ug/L
A
5
0
B
5
0
Wo. -
C
D
5
5
0
0
0.3
u L
A
5
0
B
5
0
,L;
C
5
0
D
5
0
0.4
A
5
0
ug/L _
B
5
0
a ' -'."
C
5
0
D
5
0
0.5
u
A
5
0
B
5
0
C
5
0
D
5
0
0.7
A
5
0
u
B
5
0
C
5
0
D
5
0
1.0
A
5
0
u L
B
5
0
C
5
0
D
5
0
1.4
ug/L
A
5
2
B
5
0
C
5
3
D
5
1
A
u
B
C
D
WER 48 Hour Acute Toxicity Test
Facility:
DMW
Metal:
j
Sample ID:
Batch 10-22-23
Start Date:
10/25/23 Time: 11:00 By: AM
End Date:
10/27/23 Time: 10:43 By: JC
Eff. Log #:
65991 'C,°� {-:
Upstream Log #: 65992
TEST ORGANISMS
Test Organism: Cerioda hnia dubia
for Ceriodaphnia dubia Source: i-L 10-19, M-R 10-1
Date Removed: 10/24/23
Between 1700 hrs 2200 hrs
for fathead minnows or mysids
Source:
Temperature 24-26 C. Light 16 hr It / 8 hr dk; 50-100 ft-candles
Laboratory Water DMW / SSF @ 50 m L hardness
Downstream Water Preparation
% effluent
volume
Prep. Date:
% upstream!
volume
Prep. By:
Test Solution Preparation:
Date: 10/24/23
Prep By
AM
Metal Salt:
A NO3
I Stock. Soln:
6.35 m¢ L
Nominal Conc.
mL Stock Soln,
Volume Prepared
0.17
ug/L
0.01
mL
500 mL
0.25
ug/L
0.02
mL
500 mL
0.35
ug/L
0.03
mL
500 mL
0.5
ug/L
0.04
mL
500 mL
0,7
ug/L
0.06
mL
500 mL
1.02
ug/L
0.08
mL
500 mL
1.43
ug/L
0.11
mL
500 mL
ug/L
mL
mL
Water Chemistry
Time:
Analyst:
D.O. (mg/L)
pH
DMW
Start
Final
8.0
m L
8 t S.U.
8.6 m L
83 S.U.
Downstream
Start
Final
m L
S.U.
m L
S.U.
Upstream
Start
m /L
S.U.
Effluent
Start
m L
S.U.
Test solution volume: 25 mL. Test vessels 1 oz. plastic cups. Transfer volume 0.05 mL, Test Method: per EPA Interim Guidance
Page 73 of 112

Conc.
so
MortalityNominal
24 hr 48 hr
MINE
NEE
eINENEE'En'
0
e©EENa
MIEN
EM
nm�a
nin=
tea
®®tea
Mea�a
E=
LIE
e®E■®
e�NEE®
NINE
MINE
MINE
r
©m
'
e_--
MINE
MENNEN
M_.E=
mm
��
MEN
NEE
MINE
mm
MENNEN�
MEN
NINE
M-EIIE
n_--
MEN
MINE
MEN
:e110
MEN
WER 48 Hour Acute Toxicity Test
Facility:
DMW
Metal: A
Sample ID: Batch 10-22-23
Start Date:
10/30/23 Time:
1:40 By: AM
End Date:
11/01/23 Time:
1:05 B : AM
Eff. Log #:
65991 � " �
Upstream Log #: 65992
TEST ORGANISMS
Test Organism: Cerioda hnia dubia
for Ceriodaphnia dubia Source: i-L 10-19, M-R 10-1
Date Removed: 10/24/23
Between 1700 hrs 2200 hrs
for fathead minnows or mysids
Source:
Temnrrnture'd-NF f' 1 .iuht 1 h hr It / R hr dk• 50-i no ft-candles
Laboratory Water DMW / SSF @ 50 m L hardness
Downstream Water Preparation
Luent
tream
volume
Prep. Date:
volume
Prep. Hvy
Test Solution Preparation:
Date: 10/24/23
Prep By
AM
etal Salt:
A NO3
Esmwck.Soln:
6.35 mtr L
Nominal Cone.
mL Stock Soln.
Volume Prepared
2.04
u L
0.16
mL
500 mL
2.92
u
0.23
mL
500 mL
4.17
U
0.33
mL
500 mL
UQ L
mL
mL
U L
mL
mL
U L
mL
mL
U L
mL
mL
ugLL
mL
mL
Water Chemistry
Analyst:
-Time:
D.O. (mg/L)
H
DMW
Start
Final
8.0
m L
s.t S.U.
8.6 m L
83 s.u.
Downstream
Start
Final
m L
S.U.
m
S.U.
Upstream
Start
m L
S.U.
Effluent
Start
mg/L
S.U.
Test solution volume: 25 mL. Test vessels I oz. plastic cups. Transfer volume 0.05 mL
Page 74 of 112
Test Method: per EPA Interim Guidance

24 hr
nm�Mortality
a
®tea
EM
ee■s■��s
®®ors
e®�■rs
ea�a
®tea
®®-�
ee®
■ie E
mm
ea�a
eia�a
e©tea
OEM
e©
a
ea�a
m
e®tea
eaNEWa
reINENEE�
In=
eINEN■�
I
WE48 Hour Acute Toxicity Test
Facility: LENOIR Metal: Ag
Sample ID: LOWER CREEK
Start Date: 10/25/23 Time: l 1:00 By: AM
End Date: 10/27/23 Time: 11:03 By: is
Eff. Log #: 65991 =U stream Log #: 65992
TEST ORGANISMS
Test Organism: Cerioda hnia dubia
for Ceriodaphnia duhia Source: i-L 10-19, M-R 10-1
Date Removed: 10/24/23
Between 1700 hrs 2200 hrs
for fathead minnows or mysids
Source:
Temperature 24-26 C. Light 16 hr It / 8 hr dk; 50-100 ft-candles
Laboratory Water
DMW / SSF R 50 m hardness
Downstream Water Preparation
% effluent
17.3%
volume 692
Prep. Date: 10/25/23
upstream
82.7%
volume 3308
Prep. By AM
Test Solution Preparation:
Date: 10/24/23
Prep By
AM
Metal Salt:
AgNO13
Stock. So1n:
635 m_
Nominal Cone.
mL Stock Soln.
Volume Prepared
0.7
u
0.06
mL
500 mL
1.02
u
0.09
mL
500 MI.,
1.43
u L
0.11
mL
500 mL
2.04
u
0.16
mL
500 mL
2.92
U L
0.23
mL
500 mL
4.17
u
0.33
mL
500 mL
5.96
u /L
0.47
mL
500 mL
u&,/L
mL
mL
Water Chemistry
Time:
Analyst:
D.O.(m L)
pH
DMW
Start
Final
8.0
m L
aA S.U.
8.6 m
83 S.U.
Downstream
Start
Final
8.5
m
7.3 S.U.
8.5 ma L
8.1 S.U.
U stream
Start
8.4
m L
7.2 S.U.
Effluent
Start
8.3
mQ L
7.0 s.u.
Test solution volume: 25 mL. Test vessels 1 oz. plastic cups. Transfer volume 0.05 mL. Test Method: per EPA Interim Guidance
Page 75 of 112

•24
Mortality
hr s8 hr
ee■��
e®tea
e®tea
Eem.ee■■�a
®tea
®ee�a
e®tea
e®tea
em
em��
e=��
■
m�■ee
TEST ORGANISMS
Ceriodaphnia dubia
Date Removed:
Between
fathead minnows or mysids
Source:
r • /I///L r I i�
Source: i-L 10-19, M-R 10-1
10/24/23
1700 hrs 2200 hrs
Temperature 24-26 C. Light 16 hr It / 8 hr dk; 50-100 fl-candles
Laboratory Water
DMW / SSF 250 m4 hardness
Downstream Water Preparation
17.3%
volume 259.5
1'rep Date: l0/30/23
Lfluent
stream
82.7%
volume 1240.5
Prep. 3`. AM
Test Solution Preparation:
Date: 10/24/23
Prep By
AM
Metal Salt:
A NO3
Stock. Soin:
6.35 m
Nominal Conc.
mL Stock Soln.
Volume Prepared
12.16
u
0.96
mL
500 mL
17.37
u
1.37
mL
500 mL
24.81
U
1.95
mL
500 mL
U
mL
nil.
U
mL
m1.
u
mL
m 1-
ugIL
mL
mL
u
mL
mL
Water Chemist
Time:
D.O.(m L)
PH
DMW
Start
Final
8.0
m
s.: S.U.
8.6 ma
8.3 S.U.
Downstream
Start
Final
8.5
m
7.3 S-u.
8.5 m
B I S.U.
Upstream
Start
8.4
m L
7.2 S.U.
Effluent
Start
8.3
m
7.0 S.U.
Test solution volume: 25 mL. Test vessels 1 oz. plastic cups. Transfer volume 0.05 mL.
Page 76 of 112
Test Method: per EPA Interim Guidance

ROUND 3 -APPENDIX C3
Measured Concentrations of Total Recoverable Silver in Test Solutions
Lower Creek WWTP - WER 3 Ag
ETT Environmental; 10/23
Page 77 of 112

Measured Total Recoverable and Dissolved Silver
Lenoir Lower Creek - Primary Species Site Specific Study
October 2023
Sample: Spiked Dilution Water (Diluted DMWInitial Date: 10/25/23
Nominal
Total Ag
Measured Total Recoverable Silver (µg/L)
Initial Day 1 Day 2 Day 3 Day 4 Day 5 Day 6 Day 7 Mean
% of
Nominal
0
<1.0
<1.0
0.70
0.30
0.30
43%
1.001
0.50
0.30
0.40
40%
1.40
0.50
0.80
0.65
46%
2.00
0.80
1.30
1.05
53%
2.90
1.30
2.00
1.65
57%
4.20
2.30
2.60
2.45
58%
Sample: Simulated Downstream Initial Date: 10/25/23
Nominal
Total Ag
Measured Total Recoverable Silver (µg/L)
Initial Day 1 Day 2 Day 3 Day 4 Day 5 Day 6 Day 7 Mean
% of
Nominal
0.00
<1.0
<1.0
<1.0
4.20
1.90
3.10
2.50
60%
6.00
3.70
2.60
3.15
53%
12.201
4.20
3.20
3.70
30%
17.40
3.80
4.70
4.25
24%
24.80
4.60
4.90
4.75
19%
+
+
Measured Dis. Ag (µg/L)
Initial Day 2 Mean
%
Dissolved
<1.0
<1
0.20
0.60
0.40
133%
0.20
0.80
0.50
125%
0.30
0.80
0.55
85%
0.40
0.80
0.60
57%
1.30
1.40
1.35
82%
1.70
2.50
1 2.10
1 86%
Measured Dis. Ag (µg/L)
Initial Day 2 Mean
%
Dissolved
<1.0
<1.0
<1.0
0.80
0.60
0.70
28%
0.80
0.70
0.75
24%
1.70
1.90
1.80
49%
1.30
1.60
1.45
34%
1.80
1.90
1.85
39%
Page 78 of 112

ROUND 3 - APPENDIX C4
Water Chemistry Measurements for Acute Definitive Tests
Lower Creek WWTP - WER 3 Ag
See Appendix C2
ETT Environmental; 10/23
Page 79 of 112

Lower Creek WWTP - WER 3 Ag
ROUND 3 -APPENDIX C5
Chain of Custody Documentation
ETT Environmental; 10/23
Page 80 of 112

ETT
M �-
r+w WIN
shrc 'eta'
PO Box 16414, Greenville, SC 29806-7414
[phone], [phone]
Shipping Address: 4 Craftsman Ct, Greer, SC 29650
www.ettlah.org
CHAIN OF CUSTODY RECORD
flow LC eFF- a 011t 000
Page of
Client: fit.
Program
V
Containers
Preservative
Parameters
Facility: �0
Whole Effluent rac;e;h•
a
State: C NPDES #:
Acute
Chronic
I Test Organisms
is
Q
U(Composite
only)
(Grab or Composite)
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c=
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Sign, and Print below
°:
3
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3= HCL
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the dotted line
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L'
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m
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SAMPLE ID
U
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Composite Stnrt Date Time
Sample Collection DNc Time
Collected by
a
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1-otrercreE k
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LowerGrcek-
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-------------
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Special Instructions:
Sample Custody Transfer Record
Secure
Receipt
Sample
Date Time Relinquished B / Organization Received ayj Or anization
Area
Temp °C
Preserved?
/ 0-J,1-.ol3
�--
L3JAL
0yr,
0.9
COMPOSITE SAMPLING PROCEDURES
TEMPERATURE MONITORING PROCEDURES
HOLD TIME PROCEDURES
Composite samples must be collected over a 24 hour period.
Sample temperature during collection and transport must be between
For toxicity testing the sample must first be used within 36 hours
Time Proportional: 1 sample each hour for 24 hours. Equal volui
0.0 and 6.0'C. Samples must not be frozen. Use water ice in sealed bags.
of sample collection (completion ofcomposite sample).
or at minimum 1 sample every 4 hours over 24 hours.
Sample may not be used after 72 hours from sample collection.
Plow Proportional: As per instructions in NPDES permit.
Page 81 of 112

Lower Creek WWTP - WER 3 Ag
ROUND 3 - APPENDIX C6
Statistical Analysis Results
ETT Environmental; 10/23
Page 82 of 112

LOGISTIC MODEL
Survival
Test: tenairCbtver y m W
Date: 10/25/2023
T Ag
gamma 0
1E-05
alpha
-0.094
beta
-15 sury
0
100
test conc
0.4
100
0.65
80
1.05
15
1.65
0
2.45
0
LC50
0.80537844
0
J
predicted
num denominator y
100 1 100
0.4 1.010471478 98.9637
denom 0.65 1.247511149 80.1596
1.05 6.628480352 15.08641
1.65 107.9390625 0.926449
2.45 1405.576714 0.071145
IC25 2 50
101
,off
�0 0.4 . 0.8 1.2 1
s- actual mean
actual mean
predicted reproduction
2 2.4 2.8
® predicted
reproduction
Page 83 of 112

LOGISTIC MODEL Surviv@I
Test: te#vaW+evffr
Date: 10125/2023 Dis Ag
gamma 0
1E-05
alpha
-0.24
beta
-851
sury
0
100
test conc
0.5
100
0.55
80
0.6
15
1.35
0
2.1
0
LC50 0.57543994
predicted
num denominator y
100 1 100
0.5 1.005585677 99.44463
denom 0.55 1.188403113 84.14653
0.6 5.677932705 17.61204
1.35 4.6869E+13 2.13E-12
2.1 5.6799E+20 1.76E-19
IC25 2 50
actual mean
predicted reproduction
20 -- - - - _ _.. _ --- ------ _ _ -- ----
10
00 0.4 0.8 1.2 1.6 2 2.4
*actual mean
® predicted
reproduction
Page t34 of 112

LOGISTIC MODEL
Survival
Test: Lenoir Lower
Date: 10/25/2023
T Ag
gamma 0
1 E-05
{
alpha
0.54
beta
-103 sury
0
100
test oonc
2.5
100
3.15
100
3.7
5
4.25
0
4.75
0
LC50
3,4673685
0
predicted
num denominator y
100 1 100
2.5 1.000000442 99.99996
denom 3.15 1.013650038 98.65338
3.7 19.26118153 5.191789
4.25 8992.723258 0.01112
4.75 1302039.656 7.68E-05
IC25 2 50 actual mean
predicted reproduction
Page 85 of 112

ET
environmental, Inc.
P.O. Box 16414, Greenville, SC 29606
APPENDIX D
[phone] . FAX [phone]
Craftsman Court, Greer, SC 29650
WATER EFFECT RATIO STUDY
City of Lenoir, N.C.
Lower Creek WWTP
Secondary Species - Round 4
Metal: Silver
June 2023
Lower Creek WWTP - WER 4 Ag ETT Environmental; 6/23
Page 86 of 112

TABLE OF CONTENTS
1.0 INTRODUCTION
2.0 METHODS
2.1 Experimental Design
2.2 Laboratory Dilution Water
2.3 Upstream and Effluent Sample Collection
2.4 Chemical Analyses
2.5 Preparation of Test Solutions
2.6 Test Organisms
kjll� oI.Y�1 rlI1F.y
3.1 Laboratory Water
3.2 Simulated Downstream Water
3.3 Upstream Waters
4.0 CALCULATION OF WATER EFFECT RATIO
5.0 DISCUSSION
LIST OF APPENDICES
Appendix D 1. Reference Toxicant Quality Control Chart for Pimephales promelas
Appendix D2. Survival Data for Acute Definitive Tests
Appendix D3. Measured Concentrations of Total Recoverable Silver in Test Solutions
Appendix D4. Water Chemistry Measurements for Acute Definitive Tests
Appendix D5. Chain of Custody Records
Appendix D6. Statistical Analysis Results
Lower Creek WWTP - WER 4 Ag
Page 87 of 112
ETT Environmental; 6/23

1.0 INTRODUCTION
The City of Lenoir, N.C. Lower Creek wastewater treatment plant (WWTP) discharges effluent into
LowerCreek under NPDES Permit NC0023981. ETT Environmental has been retained to conduct a "site
specific study" to determine if permitted silver limits for each effluent discharge are unnecessarily
overprotective of aquatic life. This is to be accomplished through the calculation of a water effect ratio
(WER), comparing the acute effects of silver upon the surrogate aquatic test organism Ceriodaphnia
dubia living in laboratory dilution water to the acute effects of silver to the same test species in simulated
downstream receiving water. The study used the methodology provided in the Interim Guidance on
Determination and Use of Water -Effect Ratios for Metals (EPA-823-B-94-001). In order to confirm the
results of the study it is required to conduct a round of testing with a second species, the vertebrate fish
Pimephales promelas. This report presents the results of water effect ratio testing with Pimephales
promelas.
On June 27, 2023, Lower Creek WWTP personnel collected a grab effluent water sample. Acute toxicity
tests for the Water Effect Ratio study were initiated on June28, 2023.
Laboratory Location:
NCDNR Certification #
Study Director:
Study Scientist:
Study Technicians:
Study Dates:
ETT Environmental, Inc.
4 Craftsman Court
Greer, SC 29650
022
Robert W. Kelley, Ph.D.
Amy McMahon
Jennifer Christian
June 28-30, 2023
Lower Creek WWTP - WER 4 Ag
Page 88 of 112
ETT Environmental; 6/23

2.0 METHODS
2.1
2.2
Experimental Design
The design of the study involved spiking silver into test solutions and assessing the acute
toxicity of the test solutions with 48 Hour Acute Definitive tests using the surrogate test
organism Piemphales promelas. The two test solutions assessed were 1) laboratory
dilution water, and 2) simulated downstream water at measured conditions on the day of
sampling (2.3% effluent). Acute toxicity tests were set according to U.S. EPA protocols
(EPA 821-R-02-012 Method 2000), modified according to the following parameters;
Test type:
Temperature:
Light:
Test Chambers:
Test Solution Volume:
Renewal of Test Solutions:
Test Organism Age:
# Larvae/Cup:
# Replicates/Concentration:
Feeding Regime:
Aeration:
Dilution Factor:
Test Duration:
Endpoints:
Laboratory Dilution Water
Acute Static
250C fl
100 ft.-candles; 16 hr light/8 hr dark
400 mL plastic cups
200 mL
None
< 24 hr
10
2
None
None
0.7
48 Hours
Survival
The laboratory dilution water used in all tests was diluted mineral water (DMW). In this
first round of tests the DMW was prepared at a hardness of 48.0 mg/L. This dilution
water was prepared by adding Perrier water to ultra -pure water to obtain the desired final
hardness. The procedure for the preparation of this water may be found in the EPA
manual Short Term Methods for Estimating the Chronic Toxicity of Effluents and
Receiving Waters to Freshwater Organisms (EPA 82 1 -R-02-013).
* Dilution water during the period of testing was prepared as follows;
Amount Hardness Conductivity Alkalini pH
20 L 48.0 mg/L 112 µmhos/cm 46.4 mg/L 7.9
Lower Creek WWTP - WER 4 Ag ETT Environmental; 6/23
Page 89 of 112

2.3 Sample Collection
Sampling Locations
The effluent discharges into Lower Creek. The effluent samples were collected as
composite samples. As received the effluent had no measureable residual chlorine (<0.05
mg/L). Effluent flow in the 24 hour period preceding sample collection was 2.221 mgd.
Upstream water samples were collected as grab samples upstream from the effluent
discharge point. Upstream flow was estimated based on flow at the USGS station located
at Johns River at Arney's Store (the closest USGS station to the WWTP). This estimate
was calculated as follows. On the day of sample collection the flow at the USGS
monitoring station was 395 cfs. The 25th percentile flow at the USGS station (50 cfs) was
assumed to be the 7Q10 flow. Thus, on the day of sample collection, the Johns River
flow was 7.9 times the 7Q10 flow (395 cfs / 50 cfs). The 7Q10 upstream flow at the
discharge point of the WWTP on Lower Creek is 11.82 mgd. When the factor of 7.9 is
applied to the Lower Creek 7Q10 flow, it is thereby estimated that the upstream flow on
Lower Creek on the day of sample collection was 7.9 x 11.82 mgd = 93.38 mgd
All samples were collected in half gallon plastic jugs and preserved in coolers at 0-6°C.
Samples were transferred to an ETT courier by WWTP personnel.
2.4 Chemical Analyses
Dissolved oxygen and pH were measured in one surrogate of each test concentration at
the beginning and end of the test. Temperature was monitored in three surrogate test cups
in the incubator daily. Dissolved Oxygen and pH were measured with the use of a Orion
4 Star meter. The meter is calibrated daily.
Alkalinity, hardness, total suspended solids (TSS), total organic carbon (TOC), and
specific conductance were measured on each laboratory water and effluent sample
collected.
Lower Creek WWTP - WER 4 Ag
Page 90 of 112
ETT Environmental; 6/23

Total recoverable silver was measured on each test solution at the beginning and end of the
test. Dissolved silver also was measured for each test concentration at the beginning and
end of the test. Silver analyses were conducted by ETT Environmental of Greer, SC using
Standard Methods 18t` Edition Method 3111B (flame atomic absorption), and
concentrated to achieve a detection limit of 10 ug/L (or lower with concentration).
2.5 Preparation of Test Solutions
2.5.1 Simulated Downstream Water
Based upon the measured effluent flow (2.221 mgd) and the estimated upstream flow
(93.38 mgd) , a simulated downstream sample was prepared using 2.3% effluent and
97.7% upstream water.
2.5.2 Silver Spiking
Silver was spiked as silver nitrate (Ag NO3) into laboratory water and the simulated
downstream water. Prior to spiking the total recoverable silver in each effluent sample
was measured. Each day a batch of simulated downstream water was prepared. A
microliter syringe was used to add the correct volumes of the stock solution to each
simulated effluent or control concentration to achieve the desired nominal concentration
of silver.
2.6 Test Organisms
The test organism used for this study was the fathead minnow Pimephales promelas.
Test organisms were fish larvae that were hatched on arrival in laboratory water prior to
use in the test. The fish larvae were purchased from Aquatic Biosystems of Fort Collins
Colorado and shipped overnight. Every batch of purchased test organisms is tested
using a reference toxicant to verify their health and sensitivity. Voucher specimens of
every purchased batch are preseved and set aside to be taxonomically verified by a staff
taxonomist. Only larvae from broods with <5% mortality during shipping are used.
Note: The initial revision of this report mistakenly provided a description of Ceriodaphnia
dubia test organisms. This section has been revised to correctly give information about the
fathead minnow test organisms.
Corr. by RWK 5/10/24
Lower Creek WWTP - WER 4 Ag
Page 91 of 112
ETT Environmental; 6/23

3.0 RESULTS
3.1 Laboratory Water
3.1.1 Acute Toxicity Testing Results
The acute definitive test with Pimephales promelas in laboratory water spiked with silver
showed a 48 Hour LCso of 4.9317 ug/L Total Recoverable Silver and 4.0272 ug/L
Dissolved Silver. Due to the pattern of the data, the values were calculated using the
logistic method. The survival data at each concentration are summarized as follows;
Nominal Concentration
of Total Recoverable Ag
Measured Concentration
of Total Recoverable Ag
and (Dissolved Ag)
48 Hour
Mortality
0 ug/L
<1.0 ug/L (<1.0)
0%
4.0 ug/L
3.05 ug/L (2.0)
0%
5.7 ug/L
4.35.2 ug/L (3.55)
10%
8.2 ug/L
- ug/L (-)
50%
11.7 ug/L
5.25 ug/L (4.3)
75%
16.7 ug/L
8.7 ug/L (10.7)
100%
Survival data for the test may be found in Appendix D2. Results of measured
concentrations of total recoverable and dissolved silver are provided in Appendix D3.
Statistical analysis results are found in Appendix D6.
3.1.2 Chemical Analyses
The pH in the spiked dilution water test ranged from a minimum of 7.8 to a maximum of
7.9. Dissolved oxygen was generally at the saturation point in all treatments throughout
the test.
Lower Creek WWTP - WER 4 Ag
Page 92 of 112
ETT Environmental; 6/23

3.2 Simulated Downstream Water
3.2.1 Acute Toxicity Testing Results
The acute definitive test with Pimephales promelas in downstream water spiked with
silver showed a 48 Hour LC50 of 15.3109 ug/L Total Recoverable Silver. An 48 Hour
LCso of for Dissolved Silver could not be determined because the spiked silver did
not stay in solution. Due to the pattern of the data, the value was calculated using the
logistic method. The survival data at each concentration are summarized as follows;
Nominal Concentration
of Total Recoverable
Ag
Measured Concentration
of Total Recoverable
Ag and (Dissolved Ag)
48 Hour
Mortality
0 ug/L
<1.0 ug/L
0%
5.7 ug/L
4.25 ug/L
0%
8.2 ug/L
5.2 ug/L
0%
11.7 ug/L
7.5 ug/L
20%
23.9 ug/L
17.0 ug/L
55%
34.1 ug/L
25.0 ug/L
100%
Measured concentrations were generally higher than nominal concentrations. A
significant suppression in survival was noted at a measured concentration of 17 ug/L of
total silver.
Survival data for the test may be found in Appendix D2. Results of measured
concentrations of total recoverable and dissolved silver are provided in Appendix D3.
Statistical analysis results are found in Appendix D6.
Lower Creek WWTP - WER 4 Ag
Page 93 of 112
ETT Environmental; 6/23

3.2.2 Chemical Anal
The pH in the simulated downstream water ranged from a minimum of 7.3 to a maximum
of 8.1. Dissolved oxygen was generally near the saturation point in all treatments
throughout the test. Other water chemistry parameters are summarized as follows;
Parameter
Effluent
Total Recoverable Silver (ug/L)
<0.5
Dissolved Silver (ug/L)
<0.5
Alkalinity (mg/L)
49.1
Conductivity (umhos/cm)
257
Hardness (mg/L)
42.9
Total Organic Carbon (mg/L)
4.1
Total Suspended Solids (mg/L)
4.6
It may be seen that the effluent water was characterized by low alkalinity, hardness, TOC
and TSS.
3.3 Upstream Waters
Water quality parameters measured on upstream waters are provided in the following table;
Parameter
Result
Total Recoverable Silver (µg/L)
<5
Dissolved Silver (µg/L)
<5
Total Organic Carbon (mg/L)
1.4
Alkalinity (mg/L)
30.0
Hardness (mg/L)
36.7
Conductivity (µmhos/cm)
86
Total Suspended Solids (mg/L)
21.6
Lower Creek WWTP - WER 4 Ag
Page 94 of 112
ETT Environmental; 6/23

4.0 CALCULATION OF WATER EFFECT RATIO
As noted in the results section, acute testing indicated an LCso of 4.9317 ug/L of total recoverable
silver in laboratory dilution water and an LCso of 15.3109 ug/L of total recoverable silver in 2.3%
Lower Creek WWTP downstream water. The laboratory dilution water LC50 values must be
adjusted to downstream water hardness in order to calculate the Water Effect Ratio, using the
EPA formula, as follows;
LCso x (downstream hardness/laboratory water hardness)1.72
T-Cu: 4.9317 ug/L x (36.8/48)1.72 = 3.1291 ug/L
The Water Effect Ratio can thus be calculated as follows;
Water Effect Ratio (WER)
(Total Recoverable Silver)
= LCso in Effluent
LCso in Lab Water
15.3109 ug/L = 4.8931
3.1291 ug/L
A final water effect ratio (FWER) will be calculated without use of the WER from the second
species testing.
Lower Creek WWTP - WER 4 Ag
Page 95 of 112
ETT Environmental; 6/23

ROUND 4 -APPENDIX D1
Reference Toxicant Quality Control Chart
Pimephales promelas
Lower Creek WWTP - WER 4 Ag
Page 96 of 112
ETT Environmental; 6/23

ACUTE F EFT X - 2022.23
Fathead Minnow, Toxicant Nab=-
M 8.48.48.5 8.48-4AA-
8.5 8.2 8.2 8.2 8. - 83838.
8.1
�* 7.97
$ 7.777.777.77 7.77
L0
7.5-
7. 3 7.26 27 7.28 29 7.22
-
24 7.24 .22 7.29
7. 1
7. .02
- 81
0
6.5 6.5 6.4 5.4 6.4 6 4 6 4 6.4 - - - - - -
6.5 -- r8---3-----
6.2 13.2 6.L 6.t
cc
6.0 6.1 6.1 6.1 6.1 ❑ 11
5.5
21-Jun 08-Jun 16-May 18-Apr 05-Apr 15-Mar 01-Mar 24-Jan 09-Feb 10-Jan 14-Dec
14^Jun 23-10ay 02-May 12-Apr 21-Mar 07-10ar 21-Feb 18-Jan 02-Feb 06-Jan
Date
❑
MEAN
❑
LC50
f
UPPER
❑
LOWER
UCL & LCL ARE +1- 2 STD E FROM MEAN
Page 97 of 112

48 Hour Acute Toxicity Test Benchsheet
Test Method: EPA 821 R-02-012 ; Method 2000 Pimephales promelas
Client:
ETT Reftox
Sample ID:
NaCI Lab ID# 6-21-23 AD REF TOX P
Start Date:
06/21/23
Time: 03:00 PM
Set By:
Ended By:
JG
JC
End Date: 06/23/23 Time: 02:33 PM
Test Vessel
Test Solution Volume
Incubator
Transfer Volume
Dilution Water
Fathead Minnows
500 mL plastic cup
200 mL
#1
0.5 mL
MHSF
Randomization pattern per SOP Neonates from common holding vessel
Light: 50 -100 ft-c. 16 hr light / 8 hr dark
TEST ORGANISMS
for Ceriodaphnia dubia
Date Removed: Between: and:
Pime hales promelas Source: ABS Days old: 6
M sido sis Bahia Source: a s old:
Test Organisms Pre Fed b JG Time: 1:00
MORTALITY DATA
Cumulative Mortality
- hr 48 hr 72 hr 96 hr
g/L NaCl
Comments:
Initial
Final
Temp
D.O. pH
By:
Temp
D.O. pH
By:
24.71
7.81
7.811
JG
25.21
7.71
8.31
JC
24.71
8.21
7.8
JG
25.21
7.81
8.211
JC
24.71
8.31
7.81
1 JG
25.21
7.81
8.211
JC
24.71
8.21
7.811
JG
25.21
7.71
8.211
JC
24.71
8.21
7.711
JG
25.2F--76T
8.211
JC
24.71
8.31
7.711
JG
25.21
7.51
8.211
JC
°C I
m /L
°C
I mJL
48 Hour Acute Toxicity Test Statistics
Statistical Method: Probit
48 Hour LC50 = 7.83 g/L NaCl Lower Confidence Limit NA
Upper Confidence Limit NA
Page 98 of 112

Lower Creek WWTP - WER 4 Ag
ROUND 4 -APPENDIX D2
Survival Data for Acute Definitive Tests
ETT Environmental; 6/23
Page 99 of 112

Initial revision of report did not show test end time and initial. Corr. by RWK 5/1024
Nominal
Conc.
I•:
I Mortality
!1
.um
mm-a
a
eMENNEEN
e®tea
e®tea
ME
ONE
®®tea
®tea
®E
NEE
NEE
e®tea
®_--
ae_-
NEE
Em
OEM��
MEN
©=tea
=
C
m_�
NINE
SEE
MEN
-NEW
em�a
®tea
®E
LIE
y
E---
MINE
eESEENNEW
MEN
WER 48 Hour Acute Toxicity
Test
Facility:
DMW
Metal:
Ag
Sample ID:
Start Date:
06/28/23 Time: 3:50 By:
AM
End Date:
06/30/23 Time: 2:55 By:
AM
Eff. La #:
65107 U stream Lo #:
65108
TEST ORGANISMS
Test Organism; Pime hales promelas
for Ceriodaphnia dubia Source:
Date Removed:
Between hrs hrs
for fathead minnows or mysids
Source: ABS arr as eggs 6/27/23
Temperature 24-26 C. Light 16 hr It / 8 hr dk; 50-100 ft-candles
DMW / SSF 50 m hardness
[Labo,ratoryWater
stream Water Pre
aration
%luent
stream
volume
Prep. Date:
volume
Prep. RV.
Test Solution Preparation:
Date: 06/28/23
Prep By
AM
Metal Salt:
A NO3
Stock. Sol.:
31.75 m2/L
Nominal Conc.
mL Stock Soln.
Volume Prepared
1
u
0.09
mL
600 mL
1.4
ll
0.13
mL
600 mL
2
U
0.19
mL
600 mL
2.8
ugfL
0.26
MI.
600 mL
4
U
0.38
mL
600 mL
5.7
u L
0.54
mL
600 mL
9.2
u
0.77
ML
600 mL
u
mL
mL
Water Chemist
Time:
Analyst:
D.O. m
H
DMW
Start
Final
7.7
ma
7.9 S.U.
7.8 ma
7.9 S.U.
Downstream
Start
Final
m
S.U.
m
S.U.
Upstream
Start
m L
s.U'
Effluent
Start
m
S.U.
Test solution volume: 25 mL. Test vessels 1 oz. plastic cups. Transfer volume 0.05 mL. Test Method: per EPA Interim Guidance
Page 100 of 112

an
Mortality
24 hr .;
®®e■�eee
®®tea
e��eeee■
WER 48 Hour Acute Toxicity Test
Facility: DMW
Metal. Ag
Sample ID:
Start Date: 06/30/23 Time: 3:00 By: AM
End Date: 07/02/23 Time: 3:15 By: AM
Eff. Lo #: 111FU stream Log #:
TEST ORGANISMS
Ceriodaphnia dubia Source:
Date Removed:
hrs
fathead minnows or mysids
Source:
Temperature 24-26 C. Liaht 16 hr It / 8 hr dk: 50-100 fl-candles
Water DMW / SSF na, 50 mPJL hardness
Water Preparation
effluent I volume Prep. Date:
unstream volume Pren. sv:
Test Solution Preparation:
Date: 06/28/23
Prep By
AM
Metal Salt: A NO3
Stock. Soln:
Nominal Conc,
mL Stock Soln.
Volume Prepared
11.7 UFZL
1.11 mL
600 mL
16.7 u L
1.58 mL
600 mL
u L
mr,
mL
u L
mL
mL
u L
mL
mL
u L
mL
mL
u
mL
mL
u L
mL
mL
Water Chemistry Time: Analyst:
D.O. m )
pH
DMW Start
Final
mg1L
S.u.
m
S.U.
Downstream Start
Final
m L
S.U.
m
S. U.
Upstream Start
mgZL
S.u.
Effluent Start
m
S.u.
Test solution volume: 25 mL. Test vessels 1 oz. plastic cups. Transfer volume 0.05 mL.
Page 101 of 112
Test Method: per EPA Interim Guidance

Original revision of report did not show ending date, time and initial. Corr. by RWK 5110
Nominal
Conc.
Mortalit3r
24 hr -: hr
®®tea
®®tea
®®tea
e®tee■
®®tea
®®tea
®®tea
®®tea
WER 48 Hour Acute Toxicity Test
Facility:
LENOIR
Metal: Ag
Sample ID:
LOWER CREEK
Start Date:
06/28/23 Time: 3:50 By: AM
End Date:
06/30/23 Time: 2:55 By: AM
Eff. Log #:
65107 Upstream Log #: 65108
TEST ORGANISMS
Test Organism: Pime hales promelas
for Ceriodaphnia dubia Source:
Date Removed:
Between hrs hrs
for fathead minnows or mysids
Source: ABS arr as eggs 6/27/23
Temperature 24-26 C. Light 16 hr It 18 hr dk; 50-100 ft-candles
Laboratory Water DMW / SSF a, 50 ma hardness
Downstream Water Preparation
Lfluent
stream
2.3%
volume 125.28
Prep. pate: 06/28/23
97.7%
volume 5274.72
Prep. By. AM
Test Solution Preparation:
Date: 06/28/23
Prep By
AM
tA
NO3
LSt,ck. Soln:
31.75 m L
Nominal Conc.
ml. Stock Soln.
Volume Prepared
1
u
0.09
mL
600 mL
1.4
u
O.I3
mL
600 mL
2
u L
0.19
mL
600 mL
2.8
u
0.26
mL
600 mL
4
u
0.38
mL
600 mL
5.7
u
0.54
mL
600 mL
8.2
u
0.77
mL
600 mL
11.7
u
1.11
mL
600 mL
Water Chemist
Time:
Analyst:
D.O. m )
Ptj
DMW
Start
Final
7.7
m L
7.9 s.u.
7.8 m
ae SA
Downstream
Start
Final
T1
m
75 S.U.
mg,
S.U.
U stream
Start
7.3
m L
7.3 s.u.
Effluent
Start
6.9
maL
— S.U.
Test solution volume: 25 mL, Test vessels 1 oz. plastic cups. Transfer volume 0.05 mL. Test Method: per EPA Interim Guidance
Page 102 of 112

on24
hr Mortality 48-hr
WER 48 Hour Acute Toxicity
Test
Facility:
LENOIR
Metal:
Ag
Sample ID: LOWER CREEK
Start Date:
06/30/23 Time: 3:00 By-
AM
,End Date:
07/02/23 Time: 3:20 By:
AM
Eff. Log #:
65107 JWUpstrearn Log #:
65108
TEST ORGANISMS
Test Organism:
for Ceriodaphnia duhia Source:
Date Removed:
Between hrs hrs
for fathead minnows or mysids
Source: ABS
Temperature 24-26 C. Light 16 hr It 18 hr dk; 50-100 ft-candles
Laboratory Water DMW / SSF @ 50 m L hardness
Downstream Water Preparation
Lent
ream
2.3%
volume 27.84
Prep. mete: 06/30/23
97.7%
volume 1172.16
Prep. By: AM
Test Solution Preparation:
Date: 06/28/23
Prep By
AM
Metal Salt: Ag NO3
I Stock. Soln:
Nominal Cone.
mL Stock Soln.
Volume Prepared
23.9 u L
2,26 mL
600 mL
34.1 u L
+. mL
600 mL
U L
mL
mL
U
mL
m l_
U
mL
mL
U
mL
mL
U
mL
mL
up...
mL
mL
Water Chemistr Time: \nulsst:
D.O. m L)
H
DMW Start
Final
8.2 m
8.2 S.U.
m
S.U.
Downstream Start
Final
m
S.U.
m
S.U.
Upstream Start
m
S.U.
Effluent Start
m
s.u.
Test solution volume: 25 ml.. Test vessels 1 oz. plastic cups. Transfer volume 0.05 mL. Test Method: per EPA Interim Guidance
Page 103 of 112

ROUND 4 -APPENDIX D3
Measured Concentrations of Total Recoverable Silver in Test Solutions
Lower Creek WWTP - WER 4 Ag
ETT Environmental; 6/23
Page 104 of 112

RWK 5-10-24
Measured Total Recoverable and Dissolved Silver
Lenoir Lower Creek - Primary Species Site Specific Study
June 2023
Sample: Spiked Dilution Water (Diluted DMWInitial Date: 6/28/23
Nominal
Total Ag
Measured Total Recoverable Silver (µg/L)
Initial Day 1 Day 2 Day 3 Day 4 Day 5 Day 6 Day 7 Mean
% of
Nominal
0
<2.0
0.0
<2.0
2.80
2.80
1.00
1.90
68%
4.001
4.60
1.50
3.05
76%
5.70
6.70
2.00
4.35
%
8.20
11.70
5.00
5.50
5.25%
L52%'
16.70
7.00
10.40
8.70
Sample: Simulated Downstream Initial Date: 6/28/23
Nominal
Total Ag
Measured Total Recoverable Silver (µg/L)
Initial Day 1 Day 2 Day 3 Day 4 Day 5 Day 6 Day 7 Mean
% of
Nominal
0.00
3.60
<1.0
<1.0
5.70
5.10
3.40
4.25
75%
8.20
6.80
3.60
5.20
63%
11.701
9.00
6.00
7.50
22.00
12.00
17.0034.10
16.00
34.00
25.00
d640%/o23.90
Measured Dis. Ag (µg/L)
Initial Day 2 Mean
%
Dissolved
<1.0
1.00
<1.0
3.00
2.00
2.50
132%
4.00
0.00
2.00
66%
6.10
1.00
3.55
82%
2.60
6.00
4.30
82%
4.40
17.00
1 10.70
1 123%
Page 105 of 112

ROUND 4 - APPENDIX D4
Water Chemistry Measurements for Acute Definitive Tests
Lower Creek WWTP - WER 4 Ag
See Appendix D2
ETT Environmental; 6/23
Page 106 of 112

Lower Creek WWTP - WER 4 Ag
ROUND 4 - APPENDIX D5
Chain of Custody Documentation
ETT Environmental; 6/23
Page 107 of 112

environmental
PO Box 16414, Greenville, SC 29606-7414
[phone]. [phone]
Shipping Address: 4 Craftsman Ct, Greer, SC 29650
www.ettlab.arg
CHAIN OF CUSTODY RECORD
' D I`o,� � n3 , 2A Y� t i Pt Di -f�^o oscv 7
2��ZI
Page of
Client:
�y G� I-
Program Program
Containers
Presen'ative
Pararr
/'^
Q
«'bale Gm[sent'I'axicin' 1 �1
r�
State: C �f'
NPDES #: /% �j O j �'
Ac ite Chrnnic Test Organiss
m
ca
U
(Composite only)
(Grab or Composite)
4
o
Sign, and Print below
u
o
v
1=11Ct
L ? en
s
�_
the dotted line
r
sue..
•C
.-
.�
3-sr€o
4•Naoll
SAMPLE [D
t?
CampasiteSmn nme Time
Snmp€c C.11-6— n,[� Time
Callccted br
U
Cn
Clai
Z
a
U
9
0
8 O her
F 4 V CJ C 1 ❑ '- - • &Other
LO►�Cr LrCc E
�
�—� 7 j• 3
!Q3
G� i�.•to.0
------- ----
1
CfF•
�
(Qs ID�--
UPS�.r�r,
-------------
-------------
------------
kll
ffl
�L
Special instructions:
Sample Custody Transfer Record
Secure
Receipt
Sample
I)at, Time Relinquished By / Organization Received By / Organization
Area
Tem 'C
Preserved?
7- AI
IT
r
r�2v
d
COMPOSITE SAMPLING PROCEDURES TEMPER-4TURE MONITORING PROCEDURES HOLD TIME PROCEDURES
Composite samples must be collected over a 24 dour period. Sample temperature during collection and transport must be between For toxicity testing the sample must first be used i%idiin 36 hours
Time Proportional: 1 sample each hour for 24 hours. Equal volut 0.0 and 6.0 'C. Samples must not be frozen. Use water ice in sealed bags. of sample collection (completion of composite sample).
or at minim uni I sample event 4 hours over 24 hours. Sample may not be used afier 72 hours from sample collection.
Clow Proportional: As per instructions in NPDES permit.
Page 108 of 112

Lower Creek WWTP - WER 4 Ag
ROUND 4 - APPENDIX D6
Statistical Analysis Results
ETT Environmental; 6/23
Page 109 of 112

LOGISTIC MODEL
Survival
Test: DMW Fish
Date: 6/28/2023
T A9
gamma 0
1 E-05
alpha
0.693
beta
41 sury
0
100
test cons
1.9
100
3.05
100
4.35
90
5.25
25
8.7
0
LC50
4.93173804
0
predicted
num denominator y
100 1 100
1.9 1.000000042 100
denom 3.05 1.000192251 99.98078
4.35 1.1069985 90.33436
5.25 4.045092991 24.72131
8.7 24522.10262 0.004078
IC25 2 50 actual mean
predicted reproduction
Page 110 of 112

LOGISTIC MODEL
Survival
Test: DMW Fish
Date: 6/28/2023
Dis Ag
gamma 0
1 E-05
alpha
0.605
beta
-39 sury
0
100
test conc
1.3
100
2
100
3.55
90
4.3
25
10.7
0
LC50
4.02717034
0
�3
predicted
num denominator y
100 1 100
1.3 1.000000005 100
denom 2 1.000007104 99.99929
3.55 1.118115274 89.43622
4.3 4.035177076 24.78206
10.7 15416784.78 6.49E-06
IC25 2 50
-w actual mean
actual mean
predicted reproduction
10 12
predicted
reproduction
Page 111 of 112

LOGISTIC MODEL
Survival
Test: Lenoir Fish
Date: 6/28/2023
T Ag
gamma 0
1E-05
alpha
1.185
beta
4.5
sury
0
100
test conc
4.25
100
5.2
100
7.5
80
17
45
25
0
LC50
15.3108746
0
0
10(
70
60
50
40
10[
00
predicted
num denominator y
100 1 100
4.25 1.081696036 92.44741
denom 5.2 1.121179186 89.19181
7.5 1.24790137 80.13454
17 2.226936174 44.90474
25 3.607077961 27.72327
IC25 2 50
.--.... -.......... ........... --........_...._._.
4
8
12
-E actual mean
actual mean
predicted reproduction
16 20 24 28
® predicted
reproduction
Page 112 of 112

Ag WER: 2024
Water Effect Ratio (WER) Study Review Checklist
Permittee: City of Lenoir - Lower Creek Permit No.:
Date reviewed:
Reviewer:
NCO023981
This checklist is based upon the 1994 Interim Guidance on Determination and Use of Water -Effect Ratios for Metals and applies to Method 1
described therein. The purpose of this checklist is to serve as a useful tool in reviewing Method I WER studies. The checklist does not
supercede the 1994 Interim Guidance document. In reviewing a WER study, the acceptability of each toxicity test will be evaluated
individually based upon the procedures described in the 1994 Interim WER Guidance. Page 57 of the 1994 guidance states that, "If the
procedures used deviated from those specified in the guidance, particularly in terms of acclimation, randomization, temperature control,
measurement of metal, and/or disease or disease -treatment, the test should be rejected; if deviations were numerous and/or substantial, the
test must be rejected. " Guidance concerning the calculation of the results of each test and the derivation of the individual test WERs and the
FWER is also provided in the 1994 Interim WER Guidance. Review of these results will be in accordance with the guidance document.
General Information
#
Question
(If yes, place a "Y" in box; if no, place an "N" in box. If question cannot be
answered in yes/no format, then place answer in "Comments " section.)
Workplan
Comments
1994
Guidance
page #, part
1.
Is the name, location, and description of the discharger provided?
j
62, J(3)
2.
Is the name of the study investigator provided?
62, J(1)
3.
Is the purpose for conducting the study described?
—
4.
Are requirements that are in the existing permit concerning WET testing,
TIE, and/or THE being met?
9
5.
Is pretreatment, waste minimization, or source reduction an option?
9
6.
Are applicable technology -based limits being met?
9
7.
Is a description of each sampling station provided?
62, J(4)
Page 1

Permittee: City of Lenoir - Lower Creek Permit No.: NCO023981
Individual Studies
#
Question
(Ifyes, place a "Y" in box; if no, place an "N" in box. If question cannot be
answered in yes/no format, then place answer in "Comments" section.)
Study 1
Study 2
Study 3
Comments
1994
Guidance
page #, part
Selecting Primary and Secondary Tests
8.
Species used for primary toxicity test? Ceriodaphnia dubia
C dubia
C dubia
C dubia
45-47, C
9.
Species used for secondary toxicity test? Pimephales promelas
PproinelaS
___ ___
45-47, C
Acquiring and Acclimating Test Organisms
10.
Organism culture, hold, acclimation, feed, and handling protocols
summarized?
r(
47-48,
D(1-2)
1 1 .
Were the organisms acclimated to site water prior to initiating the test?
I(
47, D(l)
12.
Were randomization procedures utilized?
r(
47, D(1)
53, G(9)
Collecting and Handling Upstream Water and Effluent
13.
Was rainfall data or stream flow data included and was upstream water
unaffected by recent runoff events? Rainfall data should be included.
iI
fI
Provided by POTW
48, E(1)
14.
Is the effluent sample representative of normal operations?
48, E(2)
15.
Was the plant operating at "normal levels"? Flow data should be included.
49, E(5)
16.
Were samples stored at 0-4°C?
48, E(4)
17.
Are chains -of -custody for samples included, accurate, and filled out
completely?
49, E(6)
18.
Were toxicity tests initiated w/in a maximum of 36 hours from the time of
sample collection? Test initiation and termination times should be included.
49, E(7)
62, J(1)
19.
If predators in the site water are a concern, was the site water filtered
through a 37-60 µm sieve or screen?
V
IV
fI
No predators in site
water
49, E(8)
Page 2

Permittee: City of Lenoir Gunpowder Creek Permit No.: NC0023736
#
Question
(If yes, place a "Y" in box; if no, place an "N" in box. If question cannot be
answered in yes/no format, then place answer in "Comments" section.)
Study 1
Study 2
Study 3
Comments
1994
Guidance
page #, part
Laboratory Dilution Water
20.
Did the lab water have TOC and TSS <5 mg/L as required?
50, F(2)
21.*
Was the hardness of the lab water between the required 40 and 220 mg/L?I(
50, F(3)
22.*
Was the lab water hardness (w/in the above range) close to the site water?
From 1997 Guidance, page 3, next to lastparagraph
I(r
i
<<1997
Guidance
23.
Are the lab water pH and alkalinity appropriate for the hardness used?
50, F(4)
Conducting Tests
24.
Was the spiking stock solution made from an appropriate reagent?
50-51,
G(4)(a-b)
25.
Was the same stock solution used for lab water and site water tests?
�I
�(i
51, G(4)(c)
26.
Was a static test run?
51, G(5)
27.
If the test ran longer than 48 h, was it a renewal test?
48 hr test
51, G(5)
28.
If it was a renewal test, were side -by -side tests renewed at the same time
and were proper procedures for renewal followed?
i�ri
not a renewal test
51, G(5)
29.
Was a range finder test conducted?
II
51, G(7)
30.
Was the dilution factor used in the definitive tests of 0.65 or greater?
��I
�I
ICI
0.7 dilution factor
53, G(8)
31.
Was an unspiked dilution water control for each test used?
53, G(9)
32.
Were at least 20 test organisms per treatment used?
j l
V
fI
53, G(9)
33.
Were two or more replicates used per treatment?
53, G(9)
Page 3

Permittee: City of Lenoir Lower Creek
Permit N(Perm it No.: NCO023981
#
Question
Study 1
Study 2
Study 3
Comments
1994
(If yes, place a "Y" in box; if no, place an "N" in box. If question cannot be
Guidance
answered yes/no format, then place answer in "Comments " section.)
MMEL
=
page #, part
34.
Were the laboratory hard water and the site water prepared in accordance
53, G(10)
with appropriate guidelines?
54, G(11)
35.
Were the test organisms (already acclimated), added to the test chambers for
54, G(12)
the side -by -side tests at the same time?
Chemical and Other Measurements
36.
Were hardness (or salinity for marine water), pH, alkalinity, TSS, and TOCii
55, H(2)
measured at test initiation for both site water and lab water?
37.
If "yes" to the above question, did the dissolved oxygen level remain
�,
55, H(3)
acceptable throughout the entire test?
38.
Were dissolved oxygen, pH, and temperature measured for each treatment at
55, H(3)
the appropriate times during the test?
39.
Were both total recoverable and dissolved metal measured for all samples?
54, H(4)
40.
Were the metal concentrations measured at the appropriate frequency?
54, H(4)(d)
41.
Were QA/QC requirements summarized?
57,
H(4)(d)(5)
Calculating and Interpreting the Results
42.
To prevent roundoff error in subsequent calculations, were at least four
57,1(1)
significant digits retained in all endpoints and WERs?
43.
Were greater than 10% of control organisms adversely affected (for acute
57, I(2)(b)
tests)?
44.
The percent of organisms that were adversely affected must have been less
57,
than 50%, and should have been less than 37%, in at least one treatment
I(2)(c)(1)
other than the control. Did this occur?
Page 4

Permittee: City of Lenoir - Lower Creek Permit No.: NCO023981
#
Question
Study 1
Study 2
Study 3
Comments
1994
(If yes, place a "Y" in box; if no, place an "N" in box. If question cannot be
Guidance
answered in yes/no format, then place answer in "Comments " section.) _
MMEL
page #, part
45.
For lab water, at least one treatment showed at least 50% of the organisms
57,
to be adversely affected?
I(2)(c)(2)
46.
For site water, at least one treatment showed at least 63% of the organisms
ij�iiI
57,
to be adversely affected?
I(2)(c)(2)
47.
Did a lower concentration kill a higher % of organisms than a higher
57,
concentration?
1(2)(c)(3)
48.
If so, did this occur for more than two concentrations affecting between 20-
57,
80% of the organisms?
1(2)(c)(3)
49.
If a static test was run, did the dissolved metal concentration at the end of 48
58, I(2)(e)
hours decrease by more than 50% from test initiation?
50.
Did it increase by more than 10% from test initiation?I
�I
—
51.
Did each individual test meet all acceptability requirements, as specified in
57,1(2)
#43-49 above?
52.
Were the LC50 (or EC50) values calculated appropriately and with similar
{I
�I
58, I(4 & 6)
statistics?
53.*
Was the hardness of the laboratory dilution water normalized (to obtain an
I
�(i
�I
39-43
adjusted LC50) according to the guidance document?
54.
Do the results from the laboratory dilution water compare with results that
We do not have access to
data from other labs.
59,1(5)
were obtained using a comparable laboratory dilution water in one or more
Results were comparable to
other laboratories?
results of the many previous
WERs we have done.
55.
Is the WER larger than 5? If so, investigate results further as specified in the
61,
1994 Interim Guidance on page 61.
1(7)(c)(3)
56.
Were summary tables provided containing metal concentrations and
y�l
9
yV
64, J(3)
organism response for each concentration?
Page 5

Permittee: City of Lenoir - Lower Creek Permit No.: NCO023981
Final Report
#
Question
Final Report
Comments
1994
(Ifyes, place a "Y" in box; if no, place an "N" in box. If question cannot
Guidance
be answered in yes/no format, then place answer in "Comments " section.)
page #, part
57.
Were toxicity tests conducted at least three weeks apart?
(
48, E(3)
58.
Three WERs for primary test developed?
y�l(
45, C(1)
59.
At least one WER for secondary test developed?
yl�
45, C(1)
60.
Are the WERs obtained with the primary and secondary tests w/in a factor
61, I(7)(b)(1)
of 3? If yes, then results are further confirmed.
61.
Does the test with the higher endpoint give the higher WER? If yes, then
61, 1(7)(b)(2)
results are further confirmed.
62.
Were both total recoverable and dissolved WERs calculated?
60,1(6)
63.
Was the final WER calculated as the geometric mean of the three individual
There were two Type I WERs, the geometric
mean was used.
37-38
test WERs? Provide the final WER in the comments section.
64.
Were acute and chronic criteria calculated? If yes, provide the results in the
Y
Acute (maximum) limit: 7.7 ug/L
—
comments section.
Chronic (average) limit: 7.7 ug/L
65.
Were any individual studies eliminated from consideration in the final
—
WER calculation? If yes, provide an explanation.
66.
Was an explanation of "unusual' observations and/or any procedural
—
deviations provided if necessary?
* As an alternative to conducting testing with laboratory water with a hardness between 40 and 220 mg/1 total hardness and then mathematically adjusting the LC50 of the
laboratory water to the segment regulatory hardness, testing can be conducted using laboratory water with the total hardness chemically adjusted to be the same as the
segment regulatory hardness. If the laboratory water is adjusted, then no mathematical adjustment should be necessary.
Additional Comments:
Page 6

Freshwater RPA - 95% Probability/95% Confidence Using Metal Translators
MAXIMUM DATA POINTS = 58
REQUIRED DATA ENTRY
Table 1. Project Information Table 2. Parameters of Concern
❑ CHECK IF HQW OR ORW WQS Name WQS Type Chronic Modifier
Facility Name
WWTP/WTP Class
NPDES Permit
Outfal I
Flow, Qw (MGD)
Receiving Stream
HUC Number
Stream Class
City of Lenoir - Lower Creek WWTP
Grade IV
NCO023981
001
6.000
Lower Creek
03050101
C
❑ Apply WS Hardness WQC
7Q10s (cfs)
7Q10w (cfs)
30Q2 (cfs)
QA (cfs)
1 Q10s (cfs)
11.75
16.77
68.00
9.74
Effluent Hardness
- - - - - - - - - - - - -
Upstream Hardness
Combined Hardness Chronic
Combined Hardness Acute
39.34 mg/L (Avg)
- - - - - - - - - - - - - - - - - - - - - -
25 mg/L (Avg)
31.34 mg/L
32 m /L
Data Source(s)
— — — — — — — — — — — — — — — — — — — --
Silver data are from DMRs. Total Silver Chronic and
Acute criteria modified by multiplying the lowest
WER of four rounds.
❑ CHECK TO APPLY MODEL
Par01
Par02
Par03
Par04
Par05
Par06E
Par07
Par08
Par09
Par10
Par11
Par12
Par13
Par14
Par15
Par16
Par17
Par18
Par19
Par20
Par21
Par22
Par23
Par24
Acute PQL Units
Arsenic
Aquactic Life
C
150
FW
340
ug/L
Arsenic
Human Health
Water Supply
C
10
HH/WS
N/A
ug/L
Beryllium
Aquatic Life
NC
6.5
FW
65
ug/L
Cadmium
Aquatic Life
NC
0.6998
FW
4.0193
ug/L
Chlorides
Aquatic Life
NC
230
FW
mg/L
Chlorinated Phenolic Compounds
Water Supply
NC
1
A
ug/L
Total Phenolic Compounds
Aquatic Life
NC
300
A
ug/L
Chromium III
Aquatic Life
NC
141.6568
FW
1108.0023
ug/L
Chromium VI
Aquatic Life
NC
11
FW
16
pg/L
Chromium, Total
Aquatic Life
NC
N/A
FW
N/A
pg/L
Copper
Aquatic Life
NC
9.5584
FW
13.2159
ug/L
Cyanide
Aquatic Life
NC
5
FW
22
10
ug/L
Fluoride
Aquatic Life
NC
1,800
FW
ug/L
Lead
Aquatic Life
NC
3.7916
FW
99.6306
ug/L
Mercury
Aquatic Life
NC
12
FW
0.5
ng/L
Molybdenum
Human Health
NC
2000
HH
ug/L
Nickel
Aquatic Life
NC
45.0711
FW
413.1087
pg/L
Nickel
Water Supply
NC
25.0000
WS
N/A
pg/L
Selenium
Aquatic Life
NC
5
FW
56
ug/L
Silver
Aquatic Life
INC
0.387678
FW
2.9288
ug/L
Zinc
Aquatic Life
NC
153.4647
FW
154.9679
ug/L
NCO023981 RPA WER, input
5/28/2024

NCO023981 RPA WER, input
5/28/2024

REASONABLE POTENTIAL ANALYSIS
H1
Effluent Hardness I
Date
Data
BDL=1/2DL
Results
1
5/9/2017
89.3
89.3
Std Dev.
2
8/15/2017
32.7
32.7
Mean
3
11/14/2017
52.2
52.2
C.V.
4
2/13/2018
31.1
31.1
n
5
5/8/2018
29.7
29.7
10th Per value
6
8/14/2018
33.4
33.4
Average Value
7
11/13/2018
98.7
98.7
Max. Value
8
2/13/2019
22.1
22.1
9
5/14/2019
18.9
18.9
10
8/13/2019
28.9
28.9
11
11/12/2019
37.1
37.1
12
2/11 /2020
47
47
13
5/12/2020
24.2
24.2
14
8/11 /2020
23.4
23.4
15
11/10/2020
21.4
21.4
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
Use "PASTE SPECIAL-
IH2
Values" then "COPY".
Maximum data points
= 58
24.0803 1
39.3400 2
0.6121 3
15 4
21.68 mg/L 5
39.34 mg/L 6
98.70 mg/L 7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
Upstream Hardness
Date Data BDL=1/2DL Results
25 25 Std Dev.
Mean
C.V.
n
10th Per value
Average Value
Max. Value
Use "PASTE SPECIAL -
Values" then "COPY".
Maximum data points
= 58
N/A
25.0000
0.0000
1
25.00 mg/L
25.00 mg/L
25.00 mg/L
-3-
NCO023981 RPA WER, data
5/28/2024

REASONABLE POTENTIAL ANALYSIS
NC0023981 RPA WER, data
- 4 - 5/28/2024

REASONABLE POTENTIAL ANALYSIS
NC0023981 RPA WER, data
- 5 - 5/28/2024

REASONABLE POTENTIAL ANALYSIS
NC0023981 RPA WER, data
- 6 - 5/28/2024

REASONABLE POTENTIAL ANALYSIS
NC0023981 RPA WER, data
- 7 - 5/28/2024

REASONABLE POTENTIAL ANALYSIS
NC0023981 RPA WER, data
- 8 - 5/28/2024

REASONABLE POTENTIAL ANALYSIS
NC0023981 RPA WER, data
- 9 - 5/28/2024

REASONABLE POTENTIAL ANALYSIS
NC0023981 RPA WER, data
- 10 - 5/28/2024

REASONABLE POTENTIAL ANALYSIS
Par20
Use "PASTE SPECIAL -
Silver
Values" then "COPY".
Maximum data points
= 58
Date
Data
BDL=1/2DL
Results
1
8/9/2021
<
0.5
0.25
Std Dev.
1.1165
2
8/10/2021
<
0.5
0.25
Mean
1.5464
3
9/7/2021
<
0.5
0.25
C.V.
0.7220
4
10/14/2021
<
0.5
0.25
n
42
5
11/15/2021
<
0.5
0.25
6
11/16/2021
<
0.5
0.25
Mult Factor =
1.11
7
12/7/2021
<
0.5
0.25
Max. Value
2.500 ug/L
8
1/27/2022
<
0.5
0.25
Max. Pred Cw
2.775 ug/L
9
2/14/2022
<
5
2.5
10
2/15/2022
<
0.5
0.25
11
3/8/2022
<
5
2.5
12
4/5/2022
<
5
2.5
13
5/16/2022
<
5
2.5
14
5/17/2022
<
5
2.5
15
6/7/2022
<
5
2.5
16
7/12/2022
<
5
2.5
17
8/8/2022
<
5
2.5
18
8/9/2022
<
5
2.5
19
9/6/2022
0.7
0.7
20
10/10/2022
<
5
2.5
21
11/15/2022
<
5
2.5
22
11/15/2022
<
5
2.5
23
12/8/2022
<
0.5
0.25
24
1 /10/2023
<
5
2.5
25
2/12/2023
<
5
2.5
26
2/13/2023
<
5
2.5
27
3/14/2023
<
5
2.5
28
4/11 /2023
<
5
2.5
29
5/15/2023
<
5
2.5
30
5/16/2023
<
5
2.5
31
6/13/2023
<
5
2.5
32
7/25/2023
<
5
2.5
33
8/7/2023
<
5
2.5
34
8/8/2023
<
5
2.5
35
9/12/2023
<
5
2.5
36
10/17/2023
<
0.5
0.25
37
11/13/2023
<
0.5
0.25
38
11/14/2023
<
0.5
0.25
39
12/12/2023
<
0.5
0.25
40
1 /16/2024
<
0.5
0.25
41
2/12/2024
<
0.5
0.25
42
2/13/2024
<
0.5
0.25
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
NCO023981 RPA WER, data
- 11 - 5/28/2024

REASONABLE POTENTIAL ANALYSIS
NC0023981 RPA WER, data
- 12 - 5/28/2024

REASONABLE POTENTIAL ANALYSIS
NC0023981 RPA WER, data
- 13 - 5/28/2024

City of Lenoir - Lower Creek WWTP
NCO023981 Freshwater RPA - 95% Probability/95% Confidence Using Metal Translators
MAXIMUM DATA POINTS = 58
Qw (MGD) =
6.0000
1Ql0S (cfs) =
9.74
7Q10S (cfs) =
11.75
7Q10W (cfs) =
16.77
30Q2 (cfs) =
NO 30Q2 DATA
Avg. Stream Flow, QA (cfs) =
68.00
Receiving Stream: Lower Creek HUC 03050101
WWTP/WTP Class: Grade IV
IWC% @ 1Q10S = 48.84453782
IWC% @ 7Q10S = 44.18052257
IWC% @ 7Q10W = 35.67318757
IWC% @ 30Q2 = N/A
IW%C @ QA = 12.03104787
Stream Class: C
Outfall 001
Qw = 6 MGD
COMBINED HARDNESS (mg/L)
Acute = 32 mg/L
Chronic = 31.34 mg/L
PARAMETER
NC STANDARDS OR EPA CRITERIA
Cl)REASONABLE
POTENTIAL RESULTS
RECOMMENDED ACTION
TYPE
J
Applied
Chronic Acute0.
n # Det. Max Pred Cw Allowable Cw
Standard
NCO023981 RPA WER, rpa
Page 14 of 15 5/28/2024

City of Lenoir - Lower Creek WWTP
NCO023981 Freshwater RPA - 95% Probability/95% Confidence Using Metal Translators
Outfall 001
Qw = 6 MGD
Acute: 5.996
Silver
NC
0.387678 FW(7Q10s) 2.9288
ug/L
42 1
2.775
------------------------------------------------
Chronic: 0.877
RP shown - apply Monthly Monitoring with Limit
24 values > Allowable Cw
Page 15 of 15
NC0023981 RPA WER, rpa
5/28/2024