#196_2022_0901_TS_FINAL

NC Department of Environmental Quality | Division of Water Resources | Laboratory Certification Branch
4405 Reedy Creek Road | 1623 Mail Service Center | Raleigh, North Carolina 27699-1623
919-733-3908

December 5, 2022

196
Mr. Chris Brigman
Town of Benson WWTP
770 Hannah Creek Road
Four Oaks, NC 27524-

Subject: North Carolina Wastewater/Groundwater Laboratory Certification Branch (NC
WW/GW LCB) Maintenance Inspection

Dear Mr. Brigman:

Enclosed is a report for the inspection performed on September 1, 2022 by Tonja Springer. I
apologize for the delay in getting this report to you. Where Finding(s) are cited in this report, a
response is required. Within thirty days, please supply this office with a written item for item
description of how these Finding(s) were corrected. Please describe the steps taken to prevent
recurrence and include an implementation date for each corrective action. If the Finding(s) cited
in the enclosed report are not corrected, enforcement actions may be recommended. For
Certification maintenance, your laboratory must continue to carry out the requirements set forth
in 15A NCAC 02H .0800.

A copy of the laboratory’s Certified Parameter List at the time of the audit is attached. This list will
not reflect any changes made during the audit. Copies of the checklists completed during the
inspection may be requested from this office. Thank you for your cooperation during the
inspection. If you have questions or need additional information, please contact me at (919) 733-
3908 Ext. 259.

Sincerely,

Beth Swanson
Technical Assistance & Compliance Specialist
Division of Water Resources

Attachment
cc: Tonja Springer, Todd Crawford, #196

On-Site Inspection Report

LABORATORY NAME: Town of Benson WWTP
NPDES PERMIT #: NC0020389
ADDRESS: 770 Hannah Creek Road
Four Oaks, NC 27524
CERTIFICATE #: 196
DATE OF INSPECTION: September 1, 2022
TYPE OF INSPECTION: Municipal Maintenance
AUDITOR: Tonja Springer

LOCAL PERSON(S) CONTACTED:

Brian Leavitt and Chris Brigman

I. INTRODUCTION:

This laboratory was inspected by a representative of the North Carolina Wastewater/Groundwater Laboratory
Certification Branch (NC WW/GW LCB) to verify its compliance with the requirements of 15A NCAC 02H
.0800 for the analysis of compliance monitoring samples.

II. GENERAL COMMENTS:

The facility is neat and well organized and has all the equipment necessary to perform the analyses. Staff
were forthcoming and responded well to suggestions from the auditor.

All required Proficiency Testing (PT) for the 2022 PT Calendar Year have been analyzed, but remedial PT
Samples and Corrective Action Reports (CARs) are pending for Unacceptable PT Sample Results.

Any time changes are made to laboratory procedures, QA/SOP document(s) must be updated and
relevant staff retrained. Staff must acknowledge that they have read and understand the changes as part
of the documented training program. The same requirements apply when changes are made in response
to Findings, Recommendations or Comments listed in this report, to ensure the methods are being
performed as stated, references to methods are accurate, and the QA and/or SOP document(s) is in
agreement with each approved practice, test, analysis, measurement, monitoring procedure or regulatory
requirement being used in the laboratory. In some instances, the laboratory may need to create an SOP
to document how new functions or policies will be implemented. Revisions to the SOPs, based on the
Findings, Comments and Recommendations within this report must be submitted to this office by
June 1, 2023.

The laboratory is reminded that SOPs are required to be reviewed at least every two years and are intended
to describe procedures exactly as they are to be performed. Use of the word “should” is not appropriate when
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describing requirements (e.g., Quality Control (QC) frequency, acceptance criteria, etc.). Evaluate all SOPs
for the proper use of the word “should”.

Contracted analyses are performed by Environment 1, Inc. (Certification # 10).

Approved Procedure documents for the analysis of the facility’s currently certified Field Parameters were
provided at the time of the inspection.

III. FINDINGS, REQUIREMENTS, COMMENTS AND RECOMMENDATIONS:

Documentation

A. Finding: Error corrections are not properly performed.

Requirement: All documentation errors shall be corrected by drawing a single line through
the error so that the original entry remains legible. Entries shall not be obliterated by erasures
or markings. Wite-Out®, correction tape, or similar products designed to obliterate
documentation shall not to be used; instead, the correction shall be written adjacent to the
error. The correction shall be initialed by the responsible individual and the date of change
documented. Ref: 15A NCAC 02H .0805 (a) (7) (E).

Comment: The laboratory does not write the date of change on the correction and there were
some instances of write-overs.

B. Finding: The laboratory is not documenting all traceability information for purchased
materials.

Requirement: 15A NCAC 02H .0805 (a) (7) (K) and (g) (7) requires laboratories to have a
documented system of traceability for the purchase, preparation, and use of all chemicals,
reagents, standards, and consumables. That system must include documentation of the
following information: Date received, Date Opened (in use), Vendor, Lot Number, and
Expiration Date (where specified). A system (e.g., traceable identifiers) must be in place that
links standard/reagent preparation information to analytical batches in which the solutions are
used. Documentation of solution preparation must include the analyst’s initials, date of
preparation, the volume or weight of standard(s) used, the solvent and final volume of the
solution. This information as well as the vendor and/or manufacturer, lot number, and
expiration date must be retained for primary standards, chemicals, reagents, and materials
used for a period of five years. Consumable materials such as pH buffers, lots of pre-made
standards and/or media, solids and bacteria filters, etc. are included in this requirement. Ref:
NC WW/GW LCB Traceability Documentation Requirements for Chemicals, Reagents,
Standards and Consumables Policy.

Comment: Buffer lot numbers and expiration dates are documented on the pH benchsheet.

Comment: Dates received and opened were written on pH buffer bottles and Total Residual
Chlorine (TRC) DPD liquid reagents boxes, as required. While this can provide a traceability
link to analyses when the chemicals are in use, that link is lost once the bottles and boxes are
discarded.

Comment: An example reagent/standard receipt log was given to the laboratory at the time
of the inspection.

C. Finding: The laboratory is not documenting the QC acceptance assessment of QC standards
on laboratory benchsheets.
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Requirement: All laboratories shall use printable laboratory benchsheets. Certified Data shall
be traceable to the associated sample analyses and shall consist of: all quality control
assessments. Each item shall be recorded each time that samples are analyzed. Ref: 15A
NCAC 02H .0805 (a) (7) (F) (xv).

Comment: This Finding applies to TRC and pH. The acceptance range for the Daily Check
Standard is documented on the benchsheet, but there is no documentation showing that the
analyst assesses the value obtained against the range. A check box indicating that the
acceptance criterion has been met would satisfy this requirement.

D. Finding: The laboratory is not documenting the barometric pressure and salinity values used
to calibrate the Dissolved Oxygen (DO) meter.

Requirement: The State Laboratory may develop Approved Procedures for Field Parameters
based upon the methods in any of the sources referenced in Parts(a)(1)(A) through (F) of this
Rule. Ref: 15A NCAC 02H .0805 (a) (1) (F).

Requirement: The following must be documented in indelible ink whenever sample analysis
is performed: Calibration variables (temperature, elevation or barometric pressure [in mmHg],
and salinity). Ref: NC WW/GW LCB Approved Procedure for the Analysis of Dissolved
Oxygen (DO).

Comment: The Hach HQ30D multimeter has an internal barometer that automatically
senses the barometric pressure.

Comment: At the time of the inspection, there was no Salinity value included in the
calibration screen. According to the instrument manual, the HQ30D meter has salinity
correction turned off by default, thus it is not used in the calibration. The laboratory would
need to verify that the salinity correction is turned off and include this information in the
SOP.
Comment: Temperature is the only calibration variable documented.

E. Finding: The laboratory does not document chemical preservation of Fecal Coliform samples.

Requirement: A record of sample collection data, sample collection time, sample collector,
and the use of proper preservatives and preservation techniques shall be maintained. Ref:
15A NCAC 02H .0805 (a) (7) (L).

Requirement: Basic documentation requirements for the sample collector include: Chemical
and/or physical preservation/treatment(s) used where required (e.g., name of preservative,
pH<2, pH>9, field filtration, TRC neutralization, etc.). Ref: NC WW/GW LCB Sample
Collection, Preservation and Receipt Requirements Policy.

Comment: Immediately after collection of samples in sterile 250 mL bottles, the laboratory
transfers the sample to commercially prepared sterile vessels that contain sodium thiosulfate
preservative.

F. Finding: The laboratory does not document the date that Fecal Coliform samples are placed
into and removed from the water bath.

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Requirement: The date and time that samples are placed into and removed from ovens,
water baths, incubators and other equipment shall be documented if a time limit is required by
the method. Ref: 15A NCAC 02H .0805 (a) (7) (F).

G. Finding: The laboratory benchsheet is lacking required documentation: the sample collector.

Requirement: All laboratories shall use printable laboratory benchsheets. Certified Data shall
be traceable to the associated sample analyses and shall consist of: the sample collector.
Each item shall be recorded each time that samples are analyzed. Ref: 15A NCAC 02H .0805
(a) (7) (F) (iv).

Comment: This Finding applies to the Fecal Coliform benchsheet.

H. Finding: The laboratory benchsheet is lacking required documentation: the method or
Standard Operating Procedure reference.

Requirement: All laboratories shall use printable laboratory benchsheets. Certified Data shall
be traceable to the associated sample analyses and shall consist of: the method or Standard
Operating Procedure. Each item shall be recorded each time samples are analyzed. Ref: 15A
NCAC 02H .0805 (a) (7) (F) (i).

Comment: The TRC method reference is documented as SM 4500 Cl G-2001 instead of SM
4500 Cl G-2011. The DO method reference is documented as SM 4500 O G-2016 and Hach
10360. The laboratory’s Certified Parameter Listing (CPL) includes both methods, however,
the laboratory only uses the LDO technology (i.e., Hach 10360). SM 4500 O G-2016 specifies
use of a membrane probe which is not being utilized. An amendment form was left with the
laboratory at the time of the inspection if they wish to delete the unused method from their
CPL.

I. Finding: All required information is not being documented when performing temperature-
measuring device verifications.

Requirement: The State Laboratory may develop Approved Procedures for Field Parameters
based upon the methods in any of the sources referenced in Parts(a)(1)(A) through (F) of this
Rule. Ref: 15A NCAC 02H .0805 (a) (1) (F).

Requirement: To verify a temperature-measuring device, read the temperature of the
temperature-measuring device against a Reference Temperature-Measuring Device and
record the two temperatures, the serial number (or other unique identifier) of each device, the
date the calibration was verified and the signature/initials of the analyst. The verification must
be performed at the temperature of use. When used to measure temperature readings for
multiple applications, the device must be verified at each temperature of use and the
appropriate correction applied at each of those temperatures. Ref: NC WW/GW LCB
Temperature Measuring-Devices used for Laboratory Operations Policy.

Requirement: All compliance temperature-measuring devices without an NIST traceable
certificate, or with an expired NIST traceable certificate, must be verified against a Reference
Temperature-Measuring Device and the process documented initially and every 12 months.
Verification documentation must include the serial number of the device being checked. The
serial number stated accuracy and expiration date of the Reference Temperature-Measuring
Device used in the comparison must also be documented. Verification data must be kept on
file and be available for inspection for 5 years. (Note: International Organization for
Standardization (ISO) 17025 compliant vendors or other Certified laboratories may provide
assistance in meeting this requirement. When an ISO compliant vendor provides this
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assistance, they must provide the serial number, accuracy and calibration date for the
Reference Temperature-Measuring Device used for the verification. When a Certified
laboratory provides this service, they must provide a copy of the NIST traceable certificate of
the Reference Temperature-Measuring Device used for the verification). Ref: NC WW/GW
LCB Approved Procedure for the Analysis of Temperature.

Comment: The serial number (or other unique identifier) of each device is not documented.

Bacteria - Coliform Fecal – IDEXX Colilert ® 18 (MPN) (Aqueous)

Comment: The laboratory is using a tiered acceptance criterion to evaluate sample duplicates. When
≤20 MPN, results must agree within 5 MPN/100mL. When >20 MPN, RPD within 25%.

Recommendation: IDEXX recommends basing acceptance on the 95% confidence range. Looking
at the sample and duplicate ranges, they are acceptable as long as those 2 ranges overlap. Go to the
following website to download a program where you can enter results and it will calculate the MPN
and 95% confidence range- https://www.idexx.com/en/water/resources/mpn-generator/. Alternately,
a chart that contains all possible MPN results with the corresponding 95% confidence levels can be
found on the technical assistance portion of the NC WW/GW LCB website.

J. Finding: The laboratory is not performing duplicates at the required frequency.

Requirement: Except where otherwise specified in an analytical method, laboratories shall
analyze five percent of all samples in duplicate to document precision. Laboratories analyzing
fewer than 20 samples per month shall analyze one duplicate during each month that samples
are analyzed. Ref: 15A NCAC 02H .0805 (a) (7) (C).

Comment: The permit requires monitoring twice per week and the laboratory analyses fewer
than 20 samples per month. A sample duplicate was not analyzed in the months of January,
March or May 2022.

Comment: The laboratory is analyzing a duplicate every other month since fewer than 20
samples are analyzed in one month.

K. Finding: The sterility of the laboratory prepared collection bottles is not being verified.

Requirement: Minimally test for sterility one sample bottle per batch sterilized in the
laboratory, or at a set percentage such as 1 to 4%. This is performed by adding sterile
dilution/rinse water to the bottle after sterilization and then subsequently analyzing it as a
sample. Document results. If sample bottles or bags are purchased pre-sterilized, verification
of sterilization is not required if the laboratory maintains copies of the Certificate of Analysis
from the vendor. Ref: NC WW/GW LCB Bacteriological Sample Bottle Sterility Test Policy.

Comment: The laboratory collects Fecal Coliform samples in a 250-mL reusable bottle before
transferring to a 120-mL commercially purchased disposable sterile vessel. The 250-mL
sample bottles are sterilized in-house and must be verified for sterility.

L. Finding: The Certificate of Analysis of the commercially prepared sterilized sample bottles is
not maintained.

Requirement: If sample bottles or bags are purchased pre-sterilized, verification of
sterilization is not required if the laboratory maintains copies of the Certificate of Analysis from
the vendor. Ref: NC WW/GW LCB Bacteriological Sample Bottle Sterility Test Policy.

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M. Finding: The laboratory does not verify the chemical preservation of Fecal Coliform samples.

Requirement: Sample preservation shall be verified and documented. Ref: 15A NCAC 02H
.0805 (a) (7) (M).

Requirement: Each chemically preserved sample must be checked for effectiveness and the
results documented. Dechlorinating agents used at the time of sampling must be documented
to have been effective (either by the sample collector or the receiving laboratory) by verifying
a chlorine residual <0.5 mg/L at a neutral pH. Ref: NC WW/GW LCB Sample Collection,
Preservation and Receipt Requirements Policy.

Comment: The effectiveness of the preservative may be verified using visual assessment of
DPD or TRC test strips.

Chlorine, Total Residual – Standard Methods, 4500 Cl G-2011 (Aqueous)

Recommendation: The laboratory currently verifies the calibration curve using 16, 40, 50, 80 and
200 µg/L standards. It is recommended that instead of the 80 µg/L standard, a 400 µg/L standard
be used to bracket possible PT values and also the Daily Check standard which has a currently
assigned value of 199 µg/L.

N. Finding: The laboratory is not analyzing a Method Blank.

Requirement: The State Laboratory may develop Approved Procedures for Field Parameters
based upon the methods in any of the sources referenced in Parts(a)(1)(A) through (F) of this
Rule. Ref: 15A NCAC 02H .0805 (a) (1) (F).

Requirement: Method Blanks would be required when using laboratory-prepared standards
[including Proficiency Testing (PT) Samples] and anytime sample dilutions are performed.
Ref: NC WW/GW LCB Approved Procedure for the Analysis of Total Residual Chlorine (DPD
Colorimetric by SM 4500 Cl G-2011).

O. Finding: Values less than the established reporting limit are being reported on the
Discharge Monitoring Report (DMR).

Requirement: The State Laboratory may develop Approved Procedures for Field
Parameters based upon the methods in any of the sources referenced in Parts(a)(1)(A)
through (F) of this Rule. Ref: 15A NCAC 02H .0805 (a) (1) (F).

Requirement: For all calibration options, the range of standard concentrations must
bracket the permitted discharge limit concentration, the range of sample concentrations to
be analyzed and anticipated PT Sample concentrations. One of the standards must have
a concentration less than the permitted Daily Maximum Limit. The lower reporting limit
concentration is equal to the lowest standard concentration. Sample concentrations that
are less than the lower reporting limit must be reported as a less-than value. Ref: NC
WW/GW LCB Approved Procedure for the Analysis of Total Residual Chlorine (DPD
Colorimetric by SM 4500 Cl G-2011).

Comment: The laboratory is reporting <10 µg/L on the DMR. The lowest standard
concentration analyzed in the most recent calibration curve verification was 16 µg/L.
Samples with concentrations less than that must be reported as <16 µg/L on the DMR.

Dissolved Oxygen – Hach 10360-2011, Rev. 1.2 (Aqueous)

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P. Finding: The meter is not calibrated using moist air for the air calibration.

Requirement: The laboratory must use moist air for the air calibration. This is accomplished
by calibrating the electrode in an environment with a high relative humidity. Using dry air for
the calibration can result in errant readings. Ref: NC WW/GW LCB Approved Procedure for
the Analysis of Dissolved Oxygen (DO).

pH – Standard Methods, 4500 H+B-2011

Q. Finding: Values were reported that exceed the method specified accuracy of 0.1 units.

Requirement: By careful use of a laboratory pH meter with good electrodes, a precision of
±0.02 unit and an accuracy of ±0.05 unit can be achieved. However, ± 0.1 pH unit represents
the limit of accuracy under normal conditions, especially for measurement of water and poorly
buffered solutions. For this reason, report pH values to the nearest 0.1 pH unit. Ref: Standard
Methods, 4500 H+ B-2011. (6).

Comment: Per PT Vendor instructions, the PT Sample results should be reported to two
decimals places, which is an exception to the requirement for Compliance Samples.

Recommendation: The laboratory currently reports pH sample results to two decimal places.
It is recommended that the laboratory continue to measure and document sample results on
the benchsheet to two decimal places, and to round to the nearest 0.1 S.U. when reporting
results on the DMR.

Proficiency Testing

R. Finding: The laboratory is not documenting PT Sample analyses in the same manner as
routine Compliance Samples.

Requirement: All PT Sample analyses must be recorded in the daily analysis records as for
any Compliance Sample. This serves as the permanent laboratory record. Ref: Proficiency
Testing Requirements, February 19, 2020, Revision 5, Section 3.6.

Requirement: The laboratory shall retain all records necessary to facilitate historical
reconstruction of the analysis and reporting of analytical results for PT Samples. This means
the laboratory must have available and retain for five years [pursuant to 15A NCAC 02H .0805
(a) (7) (E) and (g) (1)] all of the raw data, including benchsheets, instrument printouts and
calibration data, for all PT Sample analyses and the associated QC analyses conducted by
all parameter methods. Ref: Proficiency Testing Requirements, February 19, 2020, Revision
5, Section 4.0.

Requirement: The analysis of Proficiency Testing (PT) Samples is designed to evaluate the
entire process used to routinely analyze and report Compliance Sample results. PT Samples
must be analyzed the same as Compliance Samples. Also, documentation must be made on
the same benchsheets used for Compliance Samples. Ref: NC WW/GW LCB Proficiency
Testing Samples Analyzed and Documented Same as Compliance Samples Policy.

Comment: The laboratory is documenting the pH, TRC and Fecal Coliform PT Sample
analyses on a benchsheet but it is not the same benchsheet as is used for Compliance
Samples.

S. Finding: PT Samples are not being analyzed in the same manner as routine Compliance
Samples.
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Requirement: Laboratories are required to analyze an appropriate PT Sample by each
parameter method on the laboratory’s CPL. The same PT Sample may be analyzed by one
or more methods. Laboratories shall conduct the analyses in accordance with their routine
testing, calibration and reporting procedures, unless otherwise specified in the instructions
supplied by the Accredited PT Sample Provider. This means that they are to be logged in and
analyzed using the same staff, sample tracking systems, standard operating procedures
including the same equipment, reagents, calibration techniques, analytical methods,
preparatory techniques (e.g., digestions, distillations and extractions) and the same quality
control acceptance criteria. PT Samples shall not be analyzed with additional quality control.
They are not to be replicated beyond what is routine for Compliance Sample analysis.
Although, it may be routine to spike Compliance Samples, it is neither required, nor
recommended, for PT Samples. PT sample results from multiple analyses (when this is the
routine procedure) must be calculated in the same manner as routine Compliance Samples.
Ref: Proficiency Testing Requirements, February 19, 2020, Revision 5, Section 3.6.

Comment: The laboratory is currently analyzing PT Samples (i.e., TRC, Fecal, pH) in
duplicate and averaging the results. Compliance Sample are not analyzed in duplicate and
the values of the pH cannot be arithmetically averaged. Sample duplicates are not a required
QC element for Field Parameters.

T. Finding: The laboratory is not documenting the preparation of PT Samples.

Requirement: PT Samples received as ampules are diluted according to the Accredited PT
Sample Provider’s instructions. It is important to remember to document the preparation of PT
Samples in a traceable log or other traceable format. The diluted PT Sample then becomes a
routine Compliance Sample and is added to a routine sample batch for analysis. No
documentation is needed for whole volume PT Samples which require no preparation,
however the instructions must be maintained. Ref: Proficiency Testing Requirements,
February 19, 2020, Revision 5, Section 3.6.

Comment: The laboratory is retaining preparation instructions from the vendor but is not
dating and initialing them to indicate the instructions were followed. Dating and initialing the
instruction sheet for each prepared PT Sample would satisfy the documentation requirement.

QA/QC

U. Finding: The Quanti-Tray® sealer is not always checked monthly for leaks.

Requirement: If the Quanti-Tray® or Quanti-Tray®/2000 test is used, the sealer must be
checked monthly by adding a dye (e.g., bromocresol purple) to a water blank. If dye is
observed outside the wells, either perform maintenance or use another sealer. Ref: NC
WW/GW LCB Quanti-Tray® Sealer Check Policy.

Comment: The laboratory performs the Sealer check approximately every other month.

V. Finding: The thermometer used in the Fecal water bath is not verified quarterly.

Requirement: Digital temperature-measuring devices and temperature-measuring devices
used in incubators must be verified at least quarterly (i.e., every 3 months) (or sooner if the
temperature-measuring device has been exposed to temperatures beyond the manufacturer’s
recommended range of use or other stresses) against a Reference Temperature-Measuring
Device with the appropriate accuracy and the process documented. Ref: NC WW/GW LCB
Temperature Measuring-Devices used for Laboratory Operations Policy.
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Comment: The thermometer is verified annually.

W. Finding: The laboratory is not calibrating the mechanical volumetric liquid-dispensing devices
used for critical measurements at least once every six months.

Requirement: Mechanical volumetric liquid-dispensing devices (e.g., fixed and adjustable
auto-pipettors and bottle-top dispensers) used for critical volume measurements shall be
calibrated once every six months. Ref: 15A NCAC 02H .0805 (a) (7) (O).

Comment: An adjustable pipettor is used to prepare the annual TRC PT Sample and the
annual TRC calibration curve verification standards. Alternatively, the laboratory could use
Class A volumetric pipettes and forgo the use of the adjustable pipettors when preparing the
annual TRC PT Sample and annual TRC calibration curve verification standards.

X. Finding: The calibration for the Reference Temperature-Measuring Device used to check
other thermometers and/or temperature sensors has expired.

Requirement: Reference Temperature-Measuring Devices shall meet National Institute of
Standards and Technology (NIST) specifications for accuracy and shall be recalibrated in
accordance with the manufacturer's recalibration date. If no recalibration date is given, the
Reference Temperature-Measuring Device shall be recalibrated every five years. Ref: 15A
NCAC 02H .0805 (a) (7) (N) (i).

Comment: The certificate states the thermometer was due for calibration September 25,
2019.

Y. Finding: The Reference Temperature-Measuring Device is not able to distinguish
temperature changes of 0.1 °C.

Requirement: The State Laboratory may develop Approved Procedures for Field Parameters
based upon the methods in any of the sources referenced in Parts(a)(1)(A) through (F) of this
Rule. Ref: 15A NCAC 02H .0805 (a) (1) (F).

Requirement: A Reference Temperature-Measuring Device is an NIST traceable
temperature-measuring device used only to verify the calibration of other temperature-
measuring devices. It must have a stated accuracy of ± 0.5 °C, be able to distinguish
temperature changes of 0.1 °C and equilibrate rapidly. Ref: NC WW/GW LCB Approved
Procedure for the Analysis of Temperature.

Requirement: A Reference Temperature-Measuring Device is an NIST traceable
temperature-measuring device used only to verify the calibration of other temperature-
measuring devices (i.e., limited use only). This device must be able to distinguish temperature
changes of 0.1°C and equilibrate rapidly. Ref: NC WW/GW LCB Temperature-Measuring
Devices used for Laboratory Operations Policy.

Comment: The Reference Temperature-Measuring Device has divisions of 0.2 °C.

Reporting

Comment: The laboratory reports Compliance Temperature results on their DMR to one decimal
place.

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Recommendation: Unless greater precision is required by the permit or data receiving agency, it is
recommended that all temperatures reported for compliance monitoring, be reported in whole
numbers as recommended by the Precision in Discharge Monitoring Report document.

Z. Finding: Data qualifiers from the contract laboratory reports are not being transferred to the
DMR.

Requirement: Reported data associated with quality control failures, improper sample
collection, holding time exceedances, or improper preservation shall be qualified as such. Ref:
15A NCAC 02H .0805 (e) (5).

Comment: See table below for details.

Collection
Date Sample Location Parameter Missing Qualifier
1/18/2022 Effluent & Influent BOD Dilution water blank was >0.2 mg/L
1/19/2022 Effluent & Influent BOD Dilution water blank was >0.2 mg/L
1/20/2022 Effluent & Influent BOD Dilution water blank was >0.2 mg/L
1/21/2022 Effluent & Influent BOD Dilution water blank was >0.2 mg/L
1/26/2022 Effluent & Influent BOD Dilution water blank was >0.2 mg/L
2/1/2022 Effluent & Influent BOD Dilution water blank was >0.2 mg/L
2/2/2022 Effluent & Influent BOD Dilution water blank was >0.2 mg/L
2/3/2022 Effluent & Influent BOD Dilution water blank was >0.2 mg/L
2/4/2022 Effluent & Influent BOD Dilution water blank was >0.2 mg/L
2/7/2022 Effluent & Influent BOD Dilution water blank was >0.2 mg/L
2/8/2022 Effluent & Influent BOD Dilution water blank was >0.2 mg/L
2/9/2022 Effluent & Influent BOD Dilution water blank was >0.2 mg/L
2/10/2022 Effluent & Influent BOD Dilution water blank was >0.2 mg/L
2/11/2022 Effluent & Influent BOD Dilution water blank was >0.2 mg/L
2/15/2022 Effluent & Influent BOD Dilution water blank was >0.2 mg/L
2/15/2022 Effluent & Influent BOD GGA check standard was not 198 ± 30.5 mg/L
2/16/2022 Effluent & Influent BOD Dilution water blank was >0.2 mg/L
2/16/2022 Effluent & Influent BOD GGA check standard was not 198 ± 30.5 mg/L
2/17/2022 Effluent & Influent BOD Dilution water blank was >0.2 mg/L
2/21/2022 Effluent & Influent BOD GGA check standard was not 198 ± 30.5 mg/L
2/21/2022 Effluent BOD Replicate varied by more than 30%
3/1/2022 Effluent & Influent BOD GGA check standard was not 198 ± 30.5 mg/L
3/2/2022 Effluent & Influent BOD GGA check standard was not 198 ± 30.5 mg/L
3/3/2022 Effluent & Influent BOD Replicate varied by more than 30%
3/7/2022 Effluent & Influent BOD GGA check standard was not 198 ± 30.5 mg/L
3/8/2022 Effluent BOD GGA check standard was not 198 ± 30.5 mg/L
3/10/2022 Effluent & Influent BOD GGA check standard was not 198 ± 30.5 mg/L
3/10/2022 Effluent BOD Replicate varied by more than 30%
3/11/2022 Effluent BOD Replicate varied by more than 30%
3/11/2022 Effluent & Influent BOD GGA check standard was not 198 ± 30.5 mg/L
3/14/2022 Effluent & Influent BOD GGA check standard was not 198 ± 30.5 mg/L
3/15/2022 Effluent & Influent BOD GGA check standard was not 198 ± 30.5 mg/L
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3/17/2022 Effluent & Influent BOD GGA check standard was not 198 ± 30.5 mg/L
3/18/2022 Effluent & Influent BOD GGA check standard was not 198 ± 30.5 mg/L
3/21/2022 Effluent & Influent BOD GGA check standard was not 198 ± 30.5 mg/L
3/22/2022 Effluent & Influent BOD GGA check standard was not 198 ± 30.5 mg/L
3/23/2022 Effluent & Influent BOD GGA check standard was not 198 ± 30.5 mg/L
3/24/2022 Effluent & Influent BOD GGA check standard was not 198 ± 30.5 mg/L
3/25/2022 Effluent & Influent BOD GGA check standard was not 198 ± 30.5 mg/L
3/28/2022 Effluent & Influent BOD Replicate varied by more than 30%
3/29/2022 Effluent & Influent BOD Replicate varied by more than 30%
3/31/2022 Effluent & Influent BOD GGA check standard was not 198 ± 30.5 mg/L
4/1/2022 Effluent & Influent BOD GGA check standard was not 198 ± 30.5 mg/L
4/4/2022 Effluent & Influent BOD GGA check standard was not 198 ± 30.5 mg/L
4/7/2022 Effluent & Influent BOD GGA check standard was not 198 ± 30.5 mg/L
4/8/2022 Effluent & Influent BOD GGA check standard was not 198 ± 30.5 mg/L
4/11/2022 Effluent BOD Replicate varied by more than 30%
4/14/2022 Effluent BOD Replicate varied by more than 30%
5/10/2022 Influent BOD Replicate varied by more than 30%
5/16/2022 Effluent BOD Replicate varied by more than 30%
5/20/2022 Effluent BOD Replicate varied by more than 30%
5/26/2022 Effluent & Influent BOD Replicate varied by more than 30%
5/26/2022 Effluent & Influent BOD Dilution water blank was >0.2 mg/L
5/27/2022 Effluent & Influent BOD Replicate varied by more than 30%
5/27/2022 Effluent & Influent BOD Dilution water blank was >0.2 mg/L
5/31/2022 Effluent BOD Replicate varied by more than 30%
5/31/2022 Effluent & Influent BOD Dilution water blank was >0.2 mg/L
6/1/2022 Effluent BOD Replicate varied by more than 30%
6/1/2022 Effluent & Influent BOD Dilution water blank was >0.2 mg/L

Recommendation: It is recommended that you contact the appropriate Regional Office for
guidance as to whether amended DMRs will be required. A copy of this report will be made
available to the Regional Office.

AA. Finding: The laboratory does not report results of all tests on the characteristics of the effluent
when duplicate sample analyses are performed.

Requirement: The results of all tests on the characteristics of the effluent, including but not
limited to NPDES Permit Monitoring Requirements, shall be reported on monthly report forms.
Ref: 15A NCAC 02B .0506 (b) (3) (J).

Comment: If any of the results are non-compliant, the most out of control value will be
recorded in the daily cell and the rest in the comment section. If all results are compliant, the
highest value would be in the daily cell with the rest in the comment section, or the geometric
mean could be calculated and reported.

Comment: This Finding applies to Fecal Coliform.

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# 196 Town of Benson WWTP

Temperature – Standard Methods, 2550 B-2010 (Aqueous)

BB. Finding: The compliance temperature-measuring device is not checked at two temperatures
that bracket the range of observed sample temperatures.

Requirement: The State Laboratory may develop Approved Procedures for Field Parameters
based upon the methods in any of the sources referenced in Parts(a)(1)(A) through (F) of this
Rule. Ref: 15A NCAC 02H .0805 (a) (1) (F).

Requirement: To check a compliance temperature-measuring device, compare readings at
two temperatures that bracket the range of compliance samples routinely analyzed against a
National Institute of Standards and Technology (NIST) traceable temperature-measuring
device and record all four readings. The readings from both devices must agree within 0.5 ºC.
If they do not, the device may not be used for temperature compliance monitoring. Ref: NC
WW/GW LCB Approved Procedure for the Analysis of Temperature.

Comment: The compliance temperature-measuring device is checked at only one
temperature.

IV. PAPER TRAIL INVESTIGATION:

The paper trail consisted of comparing original records (e.g., laboratory benchsheets, logbooks, etc.) and
contract laboratory reports to DMRs submitted to the North Carolina Division of Water Resources. Data
were reviewed for Town of Benson WWTP (NPDES permit # NC0020389) for January, February, March,
April, May and June 2022. The facility appears to be accurately transcribing numerical data. See Finding
Z for additional details.

V. CONCLUSIONS:

Correcting the above-cited Findings and implementing the Recommendations will help this laboratory to
produce quality data and meet Certification requirements. The inspector would like to thank the staff for
their assistance during the inspection and data review process. Please respond to all Findings and
include supporting documentation, implementation dates and steps taken to prevent recurrence
for each corrective action.

Report prepared by: Tonja Springer Date: September 22, 2022
Report reviewed by: Michael Cumbus Date: September 26, 2022

Certificate Number:196
Effective Date:1/1/2022
Expiration Date:12/31/2022
Lab Name:Town of Benson WWTP
Address:770 Hannah Creek Road
Four Oaks, NC 27524-
North Carolina Wastewater/Groundwater Laboratory Certification
Certified Parameters Listing
Date of Last Amendment:8/29/2022
The above named laboratory, having duly met the requirements of 15A NCAC 2H.0800, is hereby certified for the measurement of the parameters listed below.
CERTIFIED PARAMETERS
INORGANIC
BACTERIA - COLIFORM FECAL
IDEXX Colilert ®18 (MPN) (Aqueous)
CHLORINE, TOTAL RESIDUAL
SM 4500 Cl G-2011 (Aqueous)
DISSOLVED OXYGEN
Hach 10360-2011, Rev. 1.2 (Aqueous)
SM 4500 O G-2016 (Aqueous)
pH
SM 4500 H+B-2011 (Aqueous)
TEMPERATURE
SM 2550 B-2010 (Aqueous)
This certification requires maintance of an acceptable quality assurance program, use of approved methodology, and satisfactory performance on evaluation samples. Laboratories are subject to civil penalties and/or decertification for infractions
as set forth in 15A NCAC 2H.0807.