NC0044962_Compliance Evaluation Inspection_20190212

ROY COOPER - ,,4„,_ 1� i�-
Governor „ 3i L' YAr ; 1
MICHAEL S.REGAN
Secretary * +�°'+ r.
LINDA CULPEPPER NORTH CAROLINA
Director Environmental Quality
February 12, 2019
Mr. Ricky D. Goins
Stokes County Schools RCGlVI/��
P.O. Box 50 NR/DWR
Danbury,NC 27016 FEB 19 2019
Subject: Compliance Evaluation Inspection Water,R:saui ces
North Stokes High School WWTP P rmitting Section
NPDES Permit#NC0044962
Stokes County
Dear Mr. Goins:
A Compliance Evaluation Inspection was performed by Division of Water Resources, Winston
Salem Regional Office staff person, Justin Henderson on February 11, 2019. Mr. Clifford Cain,
Operator in Responsible Charge (ORC) was present at this inspection. This type of inspection
consists of two basic parts: an in-office review of the facility files and self-monitoring data and an
on-site inspection of the facility. While the facility was found to be mostly compliant with the
subject permit, the following concerns warrant your attention and action:
1) To protect against unauthorized operation and/or manipulation of the wastewater system
components, locks should be installed on the time dosing control panel, and at the fence
entrances to the surface sand filters,and the septic and dosing tanks to restrict public access.
2) Post-calibration of the field meter, utilized to perform effluent Total Residual Chlorine
(TRC) analyses shall be performed, documented, and records available upon request.
Please see the enclosed Approved Procedure for Total Chlorine Analysis requirements. All
calibration records must be maintained for a period of at least three years per Permit
Condition Part II. Section D. (6.).
ODE „- North Carolina Department of Environmental Quality I Division of Water Resources
'�'1J� Winston-Salem Regional Office 1450 Hanes Mill Road,Suite 300 I Winston-Salem,North Carolina 27103
NDDM CAROLINA
u+�r\ r�/ 336 776.9800

•
Please refer to the enclosed compliance inspection report form for additional observations and
comments. If you have any question regarding this correspondence, please contact Justin
Henderson or me at(336) 776-9800.
Sin erel,
J,
Sherri V. Knight, P.E.
Regional Supervisor
Water Quality Regional Operations
Division of Water Resources
enc: Approved Procedure for TRC analysis
BIMS Inspection Report
cc: Clifford Cain, ORC- [e-mail]
WSRO
Central Files
NPIDESIIMit7

United States Environmental Protection'Agency Form Approved.
EPA Washington,D C 20460 OMB No.2040-0057
Water Compliance Inspection Report Approval expires 8-31-98
Section A National Data System Coding(i.e.,PCS)
Transaction Code .NPDES yr/mo/day Inspection Type Inspector Fac Type
2 IS I 3 Nc0044962 111 12 I 19/02/11 117 18[ ] 19 1 G I 2011
21111111 1111111 .111111111111111111 11111111111 166
Inspection Work Days Facility Self-Monitoring Evaluation Rating B1 QA Reserved l
67I I 70 I I 711
I 72 I N I 731
I 174
751 1 1 1 1 1 1 [80
Section B•Facility Data
Name and Location of Facility Inspected(For Industrial Users discharging to POTW,also include Entry Time/Date Permit Effective Date
POTW name and NPDES permit Number) 09 OOAM 19/02/11 17/03/01
North Stokes High School
Exit Time/Date Permit Expiration Date
PO Box 50
10 10AM 19/02/11 22/02/28
Danbury NC 270160050
Name(s)of Qnsite Representative(s)/Titles(s)/Phone and Fax Number(s) Other Facility Data
///
Clifford Curtis Cain/ORC/336-996-2841/
Name,Address of Responsible Official/Title/Phone and Fax Number
Contacted
David Burge,PO Box 50 Danbury NC 270160050//336-591-4960/
No
Section C Areas Evaluated Dunng Inspection(Check only those areas evaluated)
II Permit II Flow Measurement II Operations&Maintenance II Records/Reports
NI Self-Monitoring Program II Sludge Handling Disposal III Facility Site Review Effluent/Receiving Waters
III Laboratory
Section D-Summary of Finding/Comments(Attach additional sheets of narrative and checklists as necessary)
(See attachment summary)
Name(s)and Signature(s)of Inspector(s) Agency/Office/Phone and Fax Numbers Date
Justin,L Henderson WSRO WQ//336-776-9701/
L.9:10.Adei/ *Z//,
Signature o anage ai Q A Reviewer Agency/Office/Phone and Fax Numbers Date
/1r 9//n4
EPA Form 3560-3(Rev 9-94)Previous editions are obsolete
Page# 1

NPDES yr/mo/day Inspection Type (Cont) 1
31 NC0044962 Ill 121 1 s/oa11 117 18 i c i
Section D Summary of Finding/Comments(Attach additional sheets of narrative and checklists as necessary)
While the facility was found to be mostly compliant with the subject permit, the following concerns
warrant your attention and action
1)To protect against unauthorized operation and/or manipulation of the wastewater system
components, locks should be installed on the time dosing control panel, and at the fence entrances to
the surface sand filters, and the septic and dosing tanks to restrict public access.
2) Post-calibration of the field meter, utilized to perform effluent Total Residual Chlorine (TRC)
analyses shall be performed, documented, and records available upon request. Please see the
enclosed Approved Procedure for Total Chlorine Analysis requirements.All calibration records must be
maintained for a period of at least three years per Permit Condition Part II. Section D. (6.).
Page# 2

Permit: NC0044962 Owner-Facility: North Stokes High School
Inspection Date: 02/11/2019 Inspection Type: Compliance Evaluation
Operations & Maintenance Yes No NA NE
Is the plant generally clean with acceptable housekeeping? • ❑ El El
Does the facility analyze process control parameters, for ex MLSS, MCRT, Settleable ❑ ❑ • ❑
Solids, pH, DO, Sludge Judge, and other that are applicable?
Comment
Permit Yes No NA NE
(If the present permit expires in 6 months or less) Has the permittee submitted a new ❑ ❑ II ❑
application?
Is the facility as described in the permit? * • El ❑ ❑
#Are there any special conditions for the permit? ❑ ❑ • ❑
Is access to the plant site restricted to the general public? ❑ • ❑ ❑
Is the inspector granted access to all areas for inspection? • ❑ ❑ ❑
Comment. Access entrances are not restricted to the septic tank/dosing tank area, surface sand filters,
nor to the recirculation pump control panel. Locks should be provided at these locations to
restrict access and prevent unauthorized opeartion and/manipulation of wastewater system
components.
De-chlorination Yes No NA NE
Type of system? Tablet
Is the feed ratio proportional to chlorine amount(1 to 1)? • ❑ El ❑
Is storage appropriate for cylinders? IN ❑ ❑ ❑
#Is de-chlorination substance stored away from chlorine containers? U ❑ El ❑
Comment:
•
Are the tablets the proper size and type? • ❑ El El
Are tablet de-chlorinators operational? III ❑ El ❑
Number of tubes in use? 2
Comment:
Septic Tank Yes No NA NE
(If pumps are used) Is an audible and visual alarm operational? 0 El • ❑
Is septic tank pumped on a schedule? -II ❑ El ❑
Are pumps or syphons operating properly? • ❑ ❑ ❑
Are high and low water alarms operating properly? 0 ❑ • ❑
Comment. The septic tank is typically pumped 2/year according to residual removal records reviewed
durinq this inspection.
Page# 3

Permit NC0044962 Owner-Facility: North Stokes High School
Inspection Date: 02/11/2019 Inspection Type: Compliance Evaluation
Septic Tank Yes No NA NE
Sand Filters (Low rate) Yes No NA NE
(If pumps are used)Is an audible and visible alarm Present and operational? ❑ ❑ I ❑
Is the distribution box level and watertight? • 0 0 ❑
Is sand filter free of ponding? • ❑ ❑ ❑
Is the sand filter effluent re-circulated at a valid ratio? • ❑ ❑ ❑
#Is the sand filter surface free of algae or excessive vegetation? • 0 ❑ ❑
#Is the sand filter effluent re-circulated at a valid ratio?(Approximately 3 to 1) • ❑ ❑ 0
Comment Periodic leveling and raking of the filter bed shall be performed to prevent clogging.
Disinfection-Tablet Yes No NA NE
Are tablet chlorinators operational? • 0 ❑ ❑
Are the tablets the proper size and type? • ❑ ❑ ❑
Number of tubes in use? 2
Is the level of chlorine residual acceptable? • ❑ ❑ ❑
Is the contact chamber free of growth, or sludge buildup? • 0 ❑ 0
Is there chlorine residual prior to de-chlorination? • ❑ ❑ ❑
Comment'
Effluent Sampling Yes No NA NE
Is composite sampling flow proportional? ❑ ❑ • ❑
Is sample collected below all treatment units? • ❑ ❑ ❑
Is proper volume collected? • ❑ ❑ ❑
Is the tubing clean? ❑ ❑ • ❑
#Is proper temperature set for sample storage(kept at less than or equal to 6.0 degrees ❑ 0 IN ❑
Celsius)?
Is the facility sampling performed as required by the permit(frequency,sampling type • ❑ ❑ ❑
representative)?
Comment:
•
Page# 4

i,‘
NORTH CAROLINA WASTEWATER/GROUNDWATER LABORATORY CERTIFICATION APPROVED
PROCEDURE FOR THE ANALYSIS OF TOTAL RESIDUAL CHLORINE
(DPD COLORIMETRIC)
This document provides an approved procedure for the calorimetric analysis of Total Residual Chlorine(TRC)for compliance
monitoring per 15A NCAC 2H .0805(a)(6)(F)and(g)(3).
Holding Time:
• Samples must be analyzed within 15 minutes of collection (40 CFR Part 136 Table II). Sample analysis begins when
the reagents are added to the sample.
General Information:
' • If there is a compliance limit required by the facility permit, you must have an instrument capable of detecting
concentrations at that level, such as a spectrophotometer or filter photometer. Facilities must report actual results
down to or below the permitted limit on monthly Discharge Monitoring Report (DMR) submittals; however, the North
Carolina Division of Water Resources will treat all TRC values below 50 ug/L as zero. For example, if the facility has a
TRC permit limit of 17 pg/L and reports a TRC value of 40 pg/L on the DMR, this value will be considered compliant.
Ref: "Total Residual Chlorine 50 pg/L Compliance Level" NC Division of Water Quality, Point Source Branch
memorandum dated May 1,2008.
• If a facility has no compliance limit for TRC (just a monitoring requirement), then use of a hand-held meter,
sometimes described as a pocket colorimeter, is acceptable (see the note below regarding stormwater monitoring
requirements). For facilities using these hand-held meters, the North Carolina Division of Water Resources [formerly
the Division of Water Quality] has established the minimum reporting level at 100 pg/L.Any values obtained less than.
that concentration must be reported as "<100 pg/L". Ref: Division of Water Quality, Point Source
Compliance/Enforcement Unit letter dated August 14;2001.
o NOTE: Even though permits for stormwater monitoring do not have compliance limits, stormwater
permittees must use an instrument and analytical method capable of detecting concentrations down
to or below the specified stormwater benchmark concentration of 28 pg/L to properly assess
pollutants and the effectiveness of best management practices(BMPs).
• When using a Hach Pocket Colorimeter,follow these instructions to prepare samples for analysis:
10 mL Powder Pillows are to be used with the 10-mL glass vial under the Low Range (LR) setting on the
Pocket Colorimeter. LR range is 0.02 to 2.00 mg/L C12.
25 mL Powder Pillows are to be used with the 10-mL glass vial under the Mid Range (MR) setting on the
Pocket Colorimeter. MR range is 0.05 to 4.00 mg/L Cl2.
25 mL Powder Pillows are to be used with the 5-mL plastic vial under the High Range (HR) setting on the
Pocket Colorimeter. HR range is 0.1 to 10.0 mg/L C12.
• Since Hach Method 10014 ULR is approved by EPA as an Alternate Test Procedure (ATP), all steps in the method
must be followed. This means that the sample must be filtered, liquid reagents must be used and the Pour-Thru Cell
must be used. The Reagent Blank value must be determined each analysis day and must be<5 pg/L. The Reagent
Blank value must be subtracted from the sample result.
• When citing Standard Methods 4500-CI G-2011,the laboratory may opt to use liquid reagents and the Pour-Thru Cell,
but this is not required. Filtering samples is an allowable modification under Code of Federal Regulations, Title 40,
Part 136; Federal Register Vol. 82, No. 165,August 28,2017; 136.6. (b). '
• All standard materials used must be ACS grade or higher purity.
• Sample duplicates are not a required quality cor trol element for Field parameters.
Definitions
• Laboratory-generated Calibration Curve: A linear regression equation generated from the analysis of a series of
laboratory-prepared liquid standards. Sample results are obtained by plugging sample absorbance values into the
linear regression formula. This is usually performed automatically by direct read-out meters.
Rev.06/2018

• Factory-set Calibration Curve: An internal calibration curve, generated and stored as meter programs by the
instrument manufacturer.
• Calibration Blank Deionized or Distilled water,without chlorine and without DPD/buffer, that is used to zero the meter
when a laboratory-prepared standard is used.A sealed standard (e.g., gel) blank may also be used for this purpose
when sealed standards are used for the daily calibration verification.
• Reagent Blank Deionized or Distilled water, from the same source used to make calibration and calibration '
verification standards, that is analyzed like a sample (i.e., with DPD/buffer added). The concentration of the reagent
blank must not exceed 50% of the reporting limit (i.e., the lowest calibration or calibration verification standard
• concentration), unless otherwise specified by the reference method, or corrective action must be taken. Reagent
blanks would be required when using laboratory-prepared standards[including Proficiency Testing(PT)Samples]and
anytime sample dilutions are performed.
• Second-source Standard. A standard prepared from a source independent(e.g., different vendor, different lot#, etc.)
from that used to prepare the calibration standards.
NOTE: When using a factory-set calibration curve, all other standards are considered to be Second-source.
• Daily Check Standard:A sealed standard (e.g., gel) or a laboratory-prepared standard of known concentration of the
analyte of interest. A Daily Check Standard is used to evaluate laboratory performance and analyte recovery in a
blank matrix.
• Post-Analysis Calibration Verification Standard:A Daily Check Standard that is analyzed after all sample analyses.
Instrument Calibration or Calibration Curve Verification:
Depending upon the meter, you may either construct a Laboratory-generated Calibration Curve or verify the Factory-set
Calibration Curve initially, at least every 12 months and any time the instrument optics are serviced. Most field photometric
instruments have factory-set calibration programs, which when selected in combination with the optimum wavelength for a
particular analysis, give a direct readout in concentration. These factory-set calibration programs are acceptable for
quantitation, but due to possible analyst error,variation in sample or standard preparation, variation in reagents or malfunction
of the instrument,the Factory-set Calibration Curve must be verified as described below.
Calibration curve verification checks must be performed with the calibration curve and/or program used for sample analysis.
All compliance monitoring and PT samples must be analyzed on the prepared or verified calibration curve.
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 equal to or less than the permitted discharge 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.
For all calibration options, if routine compliance samples are filtered,the calibration/calibration verification standards must also
be filtered using a 3-micron membrane filter.This is to demonstrate that the filtration process does not remove any chlorine.
Example:
If a facility has a Total Residual Chlorine compliance limit of 28 pg/L, they must demonstrate they can accurately
quantify TRC at the compliance limit.To do this, a standard concentration of 28 pg/L or less must be analyzed. Since
a 28 pg/L standard is difficult to prepare, most laboratories choose a standard concentration that is easier to prepare,
such as 20 pg/L. This will be their lower reporting limit.Anytime a compliance sample measures less than this value
(e.g., 18 pg/L), it is reported on the eDMR as<20 pg/L.
If the laboratory chooses 400 pg/L as the highest concentration in the calibration curve or calibration curve
verification, all samples above this concentration must be diluted and reanalyzed to fall within the range of the chosen
lower reporting limit and 400 µg/L.
Calibration and Calibration Curve Verification Options: Option 1 is the most widely used calibration curve verification
option. Another certified laboratory may be able to provide assistance with the meter calibration curve and calibration curve
verification options listed below.All documentation must be maintained by the meter user.
Rev 06/2018

•
If the factory-set readings (Options 1 and 2 below) vary by more than the stated acceptance criteria, the stored calibration
program must not be used for compliance monitoring until troubleshooting is carried out to determine and correct the source
of error.
NOTE: Possible corrective actions include: re-zeroing the meter; ensuring glassware is clean and not scratched;preparing
fresh calibration standards;having the meter serviced, etc.
NOTE: General Absorbance Standards (i.e., standards with specific absorbance values plus a tolerance range that are used
to check absorbances at specific wavelengths) sometimes referred to as a "HACH DR/Check Absorbance Standard Kif,
cannot be used for the Daily Check Standard or as a calibration standard.
Option 1 —Annual Factory-set Calibration Curve Verification: This type of calibration curve verification must be
performed initially, at least every 12 months and any time the instrument optics are serviced. Zero the
instrument with a Calibration Blank and then analyze a Reagent Blank and a series of five standards (do not use gel
or sealed liquid standards for this purpose). The calibration standard values obtained must not vary by more than
10% from the known value for standard concentrations greater than or equal to 50 µg/L and must not vary by more
than 25%from the known value for standard concentrations less than 50 µg/L.
Each day compliance samples are analyzed, perform the following:
• When an annual five-standard Factory-set Calibration Curve verification is used, the laboratory must check
the calibration curve each analysis day.To do this, the laboratory must zero the instrument with a Calibration
Blank and analyze a Daily Check Standard (gel-type standards are most widely used for these purposes).
The value obtained for the Daily Check Standard must read within 10% of the true value of the Daily Check
Standard. If the obtained value is outside of the±10% range,corrective action must be taken.
• If preparing standards, analyzing a PT Sample or analyzing diluted samples, a Reagent Blank is required.
• When performing analyses at multiple sample sites in a single day, a Post-analysis Calibration Verification
Standard must be analyzed after the last sample. It is recommended that a mid-day calibration verification be
performed when samples are analyzed over an extended period of time. The value obtained for the Post-
analysis Calibration Verification Standard must read within 10% of the true value of the Post-analysis
Calibration Verification Standard. If the obtained value is outside of the ±10% range, corrective action must
be taken.
Option 2 — Daily Factory-set Calibration Curve Verification: This type of calibration curve verification must be
performed each day compliance samples are analyzed. Zero the instrument with the Calibration Blank and then
analyze a Reagent Blank and a series of three standards(do not use gel or sealed liquid standards for this purpose).
The values obtained must not vary by more than 10%of the known value for standard concentrations greater than or
equal to 50 µg/L and must not vary by more than 25% of the known value for standard concentrations less than 50
µg/L.
• When performing analyses at multiple sample sites in a single day, a Post-analysis Calibration Verification
Standard must be analyzed after the last sample. It is recommended that a mid-day calibration verification be
performed when samples are analyzed over an extended period of time. The value obtained for the Post-
analysis Calibration Verification Standard must read within 10% of the true value of the Post-analysis
Calibration Verification Standard. If the obtained value is outside of the ±10% range, corrective action must
be taken.
Option 3 — Annual Laboratory-generated Calibration Curve: This type of calibration curve must be generated
initially,at least every 12 months and any time the instrument optics are serviced.Zero the instrument with the
Calibration Blank and then analyze a Reagent Blank and a series of five standards (do not use gel or sealed liquid
standards for this purpose). The obtained values are programmed into the instrument, computer spreadsheet,
scientific calculator, or plotted manually. The correlation coefficient of the calibration curve must be n_0.995. The
calibration curve must then be verified by analyzing a Second-source Standard (gel-type standards may not be used).
The Second-source Standard must read within ±10% of its true value. Sample results are obtained from the linear
regression equation of the calibration curve.
Each day compliance samples are analyzed, perform the following:
• When an annual five-standard Laboratory-generated Calibration Curve is used, the laboratory must check
the calibration curve each analysis day.To do this,zero the instrument with a Calibration Blank and analyze a
Daily Check Standard (gel-type standards are most widely used for this purpose).The value obtained for the
Rev 06/2018

y .
Daily Check Standard must read within 10% of the true value of the Daily Check Standard. If the obtained
value is outside of the±10%range, corrective action must be taken.
• If preparing standards, analyzing a PT Sample or analyzing diluted samples, a Reagent Blank is required.
• When performing analyses at multiple sample sites in a single day, a Post-analysis Calibration Verification
Standard must be analyzed after the last sample. It is recommended that a mid-day calibration verification be
performed when samples are analyzed over an extended period of time. The value obtained for the Post-
' analysis Calibration Verification Standard must read within 10% of the true value of the Post-analysis
Calibration Verification Standard. If the obtained value is outside of the ±10% range, corrective action must
be taken.
•
Option 4—Daily Laboratory.generated Calibration Curve: This type of calibration curve must be generated each
day compliance samples are analyzed. Zero the,instrument with the Calibration Blank and then analyze a Reagent
Blank and a series of three standards (do not use gel or sealed liquid standards for this purpose). The obtained
values are programmed into the instrument, computer spreadsheet, scientific calculator, or plotted manually. The
correlation coefficient of the calibration curve must be n_0.995. Sample results are obtained from the linear regression
equation of the calibration curve.
Each day compliance samples are analyzed, perform the following:
• When a daily three-standard Laboratory-generated Calibration Curve is used, the laboratory must verify the
calibration curve each analysis day with a Daily Check Standard prepared from a second source. The
calibration check is performed immediately after calibration.The value obtained for the Daily Check Standard
must read within 10% of the true value of the Daily Check Standard. If the obtained value is outside of the
±10%range,corrective action must be taken.
• When performing analyses at multiple sites, a Post-analysis Calibration Verification Standard must be
analyzed at the end of the run. It is recommended that a mid-day calibration verification be performed when
samples are analyzed over an extended period of time. The value obtained for the Post-analysis Calibration
Verification Standard must read within 10% of the true value of the Post-analysis Calibration Verification
Standard. If the obtained value is outside of the±10% range,corrective action must be taken.
Standard Solutions:
You may prepare a stock standard solution of potassium permanganate or chlorine and subsequent standard solutions as
described in Standard Methods 4500-CI G—2011, DPD Colorimetric Method, Sections 4(a)(1)and (2), page 4-69.
If liquid chlorine standard solutions with a stated range and average value are used, the average value must be used for the
true value of the standard. These standards may only be used for the Daily Check Standard and may not be used for
generating or verifying a calibration curve.
Purchased "gel-type" or sealed liquid standards may be used only for daily calibration curve verifications. These standards
must have a true value assigned initially and with each subsequent calibration curve generation/verification thereafter. When
this is done, these standards may be used afterthe manufacturer's expiration date. It is only necessary to assign a true value
to the gel-type or sealed liquid standard which falls within the concentration range of the calibration curve used to measure
sample concentrations. For example, if you are measuring samples against a low-range calibration curve, a 200 µg/L
standard would be verified, and not the 800 µg/L standard since the 800 µg/L standard would be measured using a high-range
calibration curve.
To assign a true value to the gel-type or sealed liquid standard:
1. Zero the instrument with the calibration blank.
2. Read and record gel standard values.
3. Repeat steps 1 and 2 at least two more times.
4. Assign the average value as the true value.
The assigned true value will be used until a new calibration curve verification is performed and the true value is reassigned.
The gel/sealed liquid standard true value assignment must be performed for each instrument on which they are to be used. If
multiple instruments and/or standard sets are used, each must have assigned true values specific for the instrument and
standard set. Documentation must link the gel/sealed liquid standard identification to the meter with which the assigned value
was determined.
Rev 06/2018

J
Equipment Maintenance:
As cited in the Laboratory Certification rules, "Each facility must have glassware, chemicals, supplies, equipment, and a
source of distilled or deionized water that will meet the minimum criteria of the approved methodologies." Ref: 15A NCAC 2H
.0805 (g) (4). Meeting the minimum criteria means the equipment must also be properly maintained. Clean and maintain
equipment as indicated by the manufacturer's instructions. Sample lines and the Pour-Thru Cell can become discolored and
clogged due to a buildup of colored reaction products or algae growth.
Hach Method 10014 ULR offers the following instructions for cleaning the pour-thru cell:
Cleaning the Pour-Thru Cell
The Pour-Thru Cell may accumulate a buildup of colored reaction products, especially if the reacted solutions are allowed to
remain in the cell for long periods after measurement. Remove the buildup by rinsing the cell with 5.25 N sulfuric acid followed
by rinsing with deionized water.
If your facility does not have access to or is not comfortable using sulfuric acid cleaning solution, a contract laboratory or
vendor may perform this service. Please exercise proper safety precautions when handling acid solutions.
Check condition of sample cells prior to use. They must be clean, clear of fingerprints and free of scratches. Also note
orientation of cells in the instrument. Ensure proper placement of indexed cells. Note that there are two options for Pour-
Thru Cell placement. One gives a 1-inch cell path length and when rotated 90°, gives a%-inch cell path length. Ensure the
1-inch cell path length is used.
Daily Sample Analysis Procedure:
• Zero meter
• Analyze Daily Check Standard
• Analyze Reagent Blank, if applicable
• Collect sample(sample may be collected before or after calibration or calibration check)
• Add DPD/buffer within 15 minutes bf collection
• Wait 3-6 minutes
• Read sample result
• Document required information
Documentation:
The following must be documented in indelible ink whenever sample analysis is performed:
1. Date and time of sample collection
2. Date and time of sample analysis to verify the 15-minute holding time is met[Alternatively,one time
may be documented for collection and analysis with the notation that samples are measured in situ or immediately at
the sample site.]
3. Facility name, sample site(ID or location), and permit number
4. Collector's/analyst's name or initials
5. Daily Check Standard analysis time(s)
6. Preparation procedure and true values of laboratory-prepared standards,when applicable
• 7. True value of the Daily Check Standard(s)
8. Value obtained for the Daily Check Standard(s) (verification of±10% recovery)
9. Value obtained for the Reagent Blank, when prepared standards, PT Samples or diluted samples are analyzed
(verification of 5'/z the concentration of the lowest calibration standard)
10. All data must be documented and reported in units of measure as specified in the permit (e.g., mg/L for regular ,
level or pg/L for low level)
11. True value and value obtained for the Post-analysis Calibration Verification Standard(s),where applicable
12. Traceability for chemicals, reagents, standards and consumables
13. Instrument identification(serial number preferred)
14. Date of most recent calibration curve generation or calibration curve verification
15. Statement that samples were filtered,when applicable
16. Parameter analyzed
17. Method reference
18. Data qualifier(s),when applicable
19. Equipment maintenance(recommended)
Rev 06/2018

Refer to Quality Assurance Policies for Field Laboratories (at htto://dea.nc.gov/about/divisions/water-
resources/water-resources-data/water-sciences-home-paqe/laboratory-certification-branch/technical-
assistance-policies)for additional quality assurance and quality control requirements.
This document was prepared using Standard Methods 4500-CI G—2011 and Hach Methods 8167, 10250 and 10014
ULR as references. ,
•
•
•
Rev 06/2018