NC0086550_Bioassay Inspection_20030218

Michael F. Easley, Governor
William G. Ross Jr., Secretary
North Carolina Department of Environment and Natural Resources
Alan W. Klimek, P.E. Director
Division of Water Quality
February 18, 2003
Jeffrey Lewis
Town of Fairmont
421 South Main St
Fairmont NC 28340
SUBJECT: November 18, 2002 Bioassay Compliance Inspection
Town of Fairmont
Fairmont Regional WWTP
Permit No: NC0086550
Robeson County
Dear Lewis:
Enclosed please find a copy of the Bioassay Compliance Inspection form from the inspection
conducted by Dale Lopez, Environmental Specialist, on November 18, 2002. The facility was
found to be in Compliance with permit NC0086550.
During the week of November 18 to November 22, bioassay samples were split with your facility.
The DWQ samples were sent to the DWQ Aquatic Toxicity Unit, and these aquatic toxicity
samples resulted in a "Pass" of >90%, and would not be predicted to have receiving stream
impacts. The analytical results of the 24-hour composite sample that was collected from October
18 to October 19 are as follows: BOD = 2.3 mg/L, TSS = 4 mg/L, ammonia as N = 0.03 mg/L,
TKN = 0.89 mg/L, Nitrate plus Nitrite as N = 7.2 mg/L, and Total Phosphorus = 0.77 mg/L.
During the inspection, it was noticed that the effluent weir was positioned in a way that may affect
the flow measurement accuracy: the flow took a 90-degree turn immediately before it went over
the weir. Please note that as the chlorinated wastewater flowed across the weir, the downstream
flow contacted the wall that held the weir. However, the upstream flow did not contact the weir's
supporting wall. This might indicate an uneven flow going across the weir due to the direction of
the flow. Enclosed with this report are pages 26 — 31, copied from Isco Open Channel Flow
Measurement Handbook, Fifth Edition, Chapter Three. On page 29, please review numbers 2 and
7. In part, the enclosure addresses this concern: "To ensure accurate discharge measurement,
there are certain general weir design requirements that apply to all types..."of weirs: "the upstream
face of the weir should be ... perpendicular to the axis of the channel...". "The approach section
should be straight upstream from the weir for a distance of at least 20 times the maximum expected
head of liquid...". The head depth could possibly be affected by the sudden change of flow
direction and by the dead-end section immediately prior to the weir. In order to determine if there
is an issue with this, please do the following: during maximum flow periods and during periods
when only one chlorine contact unit is on-line, please investigate the head depths across the entire
length of the weir crest by taking several measurements along its length.
1617 Mail Service Center
Raleigh, NC 27699-1617 [phone]
Customer Service 1 800 623-7748
:NCOENR.

Mr. Lewis
Page 2
February 18, 2003
Please refer to the enclosed inspection report Section D: Summary of Finding/Comments, for
additional observations and comments. Corrected copies of the 001 Effluent August 2002 DMR
must be sent as according to numbers 9 and 10 of the NPDES COMPLIANCE REMINDERS list
enclosed with this inspection report. Please be aware that the facility's laboratory must
immediately become certified for testing of laboratory field parameters.
" Please respond in writing to this office concerning all items in Section D of this report by March
31, 2003. If you or your staff have any questions, please call me at 910-468-1541.
Sincerely,
Dale Lopez
Environmental Specialist
/dl
Enclosures: Regional Field Inspectors Check List for Field Parameters
Facility Site Review
NPDES Compliance Reminders
Isco Open Channel Flow Measurement Handbook, 5th Ed., Chap. 3, pp. 26-31
cc: Johnny J. Britt, ORC
Kevin Bowden, DWQ, ESB, ATU
Central Files
Fayetteville Files

United States Environmental Protection Agency 1
EPA Washington, D.C. 20460
Water Compliance Inspection Report
Form Approved.
OMB No. 2040-0057
Approval expires 8-31-98
Section A: National Data System Coding (i.e., PCS)
Transaction Code NPDES yr/mo/day Inspection
ILJ1 2 I 1 11 12 I 117
NC00e6550 02/11/18
Type Inspector FacType
18u' 19'su 20 u'I
I I I I I I I I I I I I I I I 166
LRemarks
211 I I I I I I I I I I I I 1 I 1 I I I I I I I I I I I I I I I
Inspection Work Days Facility Self -Monitoring Evaluation Rating B1 QA Reserved
67 I 5. 0 1 69 70 I,LJ 1 I 71 1„ 72 1,,,1 73 11 174 751
IJ
1 1 1 1 1 1 11"Section
B: Facility Data
Name and Location of Facility Inspected (For Industrial Users discharging to POTW, also include
POTW name and NPDES permit Number)
Fairmont Regional WWTP
off U.S: Highway 74
Fairmont NC 28340
Entry Time/Date
10:00 AM 02/11/18
Permit Effective Date
99/07/01
Exit Time/Date
03:00 PM 02/11/18
Permit Expiration Date
04/07/31
Name(s) of Onsite Representative(s)/Titles(s)/Phone and Fax Number(s)
Johnny J. Britt/ORC/910-628-8732/
Johnny Britt//910-277-0833/
Other Facility Data
Name, Address of Responsible Official/Title/Phone and Fax Number
Contacted
Jeffrey Lewis,421 South Main St Fairmont NC 28340//910-628-9766/ No
Section C: Areas Evaluated During Inspection (Check only those areas evaluated)
Other
Section D: Summary of Finding/Comments (Attach additional sheets of narrative and checklists as necessary)
Laboratory was not certified for field parameters. For chlorine, an annual standard curve of five
standards was not analyzed and a daily standard was not analyzed. The grit chamber pump was not in
service, repairs were in progress as warranty work. The Discharge 001 effluent was not flow
proportional; Jim Haven will probably
(cont.)
Name(s) and Signature(s) of Inspector(s) Agency/Office/Phone and Fax Numbers Date
7
e opez FRO WQ/;910-469-1541/910-486-0707 /1/ � 0
Signature of•Mariagement 9 A Reviewer Agency/Office/Phone and Fax Numbers • Date
.—
f/
EPA Form 3560-3 (Rev 9-94) Previous editions are obsolete.

NPDES yr/mo/day Inspection Type
3 NC0086550 1 11 121 02/11/18 17 18
(cont.)
Section D: Summary of Finding/Comments (Attach additional sheets of narrative and checklists as necessary)
replace it. The extra sulfur dioxide dechlorination cylinders were not chained for proper storage.
HACH CL17 chlorine analyzer (after dechlorination) was not working and may have been out of service
because of an electricity surge. Two pH values on the 001 Discharge DMR for August 2002 did not agree
with the pH laboratory bench sheet: August 5 (should be 8.0 instead of 6.8) and August 7 (should be 7.9
instead of 7.0). The corrected DMR for August 2002 must be sent as according to numbers 9 and 10 of the
NPDES COMPLIANCE REMINDERS list enclosed with this inspection report. The effluent flow meter
calibration report could not be located--- PLEASE SEND THIS OFFICE A COPY OF THE FLOW METER CALIBRATION
REPORT.

Regional Field Inspectors Check List for Field Parameters
Name of site to be Inspected: Fairmont .Date: 11/18/02
Field certification # (if applicable):
NPDES #: NC0086550
Inspector: Dale Lopez
Region: FRO
I. Circle the parameter or parameters performed at this site.
Residual Chlorine
, Settleable Solids,
II. Instrumentation:
pH
DO
Conductivity,
Temperature
A. Does the facility have the equipment necessary to analyze field parameters as circled above?
1. A pH meter
2. A Residual Chlorine meter
3. DOmeter
Spectra Chor + Plus
fYSI 550 DO Meter
4. A Cone for settleable solids
Yes
Yes
Yes
Yes
No
No
No
No
5. A thermometer or meter that measures temperature. Yes No
Digital Thermometer
6. Conductivity meter
III. Calibration/Analysis:
1. Is the pH meter calibrated with 2 buffers and
checked with a third buffer each day of use?
3 buffers (4, 7, & 10 are used to slope pH meter)
2: For Total Residual Chlorine, is a check standard
analyzed each day of use?
3. Is the air calibration of the DO meter performed
each day of use?
4. For Settleable Solids, is.1. liter of sample
settled for 1 hour?
5. Is the temperature measuring device calibrated
annually against a certified thermometer?
6. For Conductivity, is a calibration standard
analyzed each day of use?
Yes
Yes
Yes
fres
Yes
Yes
Yes
No
No
No
No
No
No
???

IV. Documentation:
1. Is the date and time that the sample was collected documented?
2. Is the sample site documented?
3. Is the sample collector documented?
4. Is the analysis date and time documented?
5. Did the analyst sign the documentation?
6. Is record of calibration documented?
7. For Settleable Solids, is sample volume and
1 hour time settling time documented?
8. For Temperature, is the annual calibration of
the measuring device documented?
Comments:
fYes
Yes
h{es
Yes
Yes
'Yes
Yes
Yes
No
No
No
No
No
No
No
No
Please submit a copy of this completed form to the Laboratory Certification Program.
DWQ Lab Certification
Chemistry Lab
Courier# 52-01-01
FIELD INSPECTOR CHECKLIST REV. 04/23/2002

QIA114-1-0-1
Section D: Summary of Findings/Comments
Brief Facility Description:
FACILITY SITE REVIEW
No N/A 1. Treatment units properly operated and maintained.
N/A 2. Standby power or other equivalent provision provided.
r)es No N/A 3. Adequate alarm system for power or equipment failure available.
4. Sludge disposal procedures appropriate:
Yes No N/A a. Disposal of sludge according to regulations
Yes No N/A b. State approval for sludge disposal received.
Yes No N/A 5. Suffigien sl .:e d, spos d of to maintain treatment process equilibrium.
/t.e Ceti• ,/1t!....
No N/A 6. The ORC and Backup Operator are officially designated with
NCDENR/DWQ Training and Certification Unit.
Yes! No N/A 7. Adequate spare parts and supplies inventory maintained. - Q 44•41d
070 No N/A 8. Plant has general safety structures such as rails around or covers over
tanks, pits, or wells.
es ) No • N/A 9. Plant is generally clean, free from open trash areas.
10. Screening:
a. Manual
b. Mechanical .
N/A c. Buildup of debris
N/A d. Screenings properly disposed of
11. Grit Removal:
Yes No N/A a. Excessive organic content in the grit chamber
N/A b. Excessive odors
Yes , o N/A c. Grit properly disposed of.

Page 2
Yes No
Yes No
Yes . No
Yes No
Yes No
Yes No
Yes No
Yes No
Yes No
Yes No
Yes No
Yes No
Yes No
Yes No
Yes No
Yes No
Yes No
Yes No
Yes
Yes
Yes
Yes
Yes
Yes
Yes
N/A
NoN/A
N/A
N/A
N/A
N/A
N/A
Yes N
Yes No
Yes No
Yes No
N/A�
N/A
N/A
N/A
Primary clarifier:
a. Excessive gas bubbles
b. Black and odorous wastewater
c. Poor suspended solids removed
d. Excessive buildup of solids in center well of circular clarifier
e. Weirs level
f. Weir blockage
g. Evidence of short circuiting
h. Lack of adequate scum removal
i. Excessive floating sludge
j. Broken sludge scraper.
13. Trickling Filter:
a. Trickling filter ponding(indicating clogged media)
b. Leak at center column of trickling filter's distribution arms
c. Uneven distribution of flow on trickling filter surface
d. Uneven or discolored growth
e. Excessive sloughing of growth
f. Odor
g. Clogging of trickling filter's distribution arm orifices
h. Filter flies, worms, or snails.
14. Activated Sludge Basins/Oxidation Ditches:
a. Dead spots
b. Failure of surface aerators
c. Air rising in clumps
d. Dark foam or bad color
e. Thick billows of white, sudsy foam
f. Air rising unevenly
g. Excessive air leaks in compressed air piping.
15. Stabilization Ponds/Lagoons:
a. Excessive weeds including duckweed in stabilization ponds
b. Dead fish or aquatic organisms
c. Buildup of solids around influent pipe
d. Excessive scum on surface.

Page 3
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes No
Yes No
Yes No
Yes No
Yes No
Yes No
Yes
Yes
Yes
Yes
es
Yes No
No
No N/A
No N/A
16. Secondary Clarifier:
N/A a. Excessive gas bubbles on surface
N/A b. Level overflow weirs
;N/A c. Weir blockage
N/A d: Evidence of short circuiting
N/A e. Excessive buildup of solids iri center well of circular clarifier
N/A f. Pin floc in overflow
N/A g. Effective scum rake
N/A h. Floating sludge on surface
N/A i. Excessive high sludge blanket
N/A j. Clogged sludge withdrawal ports on secondary clarifier.
17. Filtration:
a. Filter surface clogging
b. Short filter run
c. Gravel displacement of filter media
d. Loss of filter media during backwashing
e. Recycled filter backwash water in excess of 5 percent
f. Formation of mudballs in filter media.
18. Chlorination Unit:
a. Sludge buildup in contact chamber
b. Gas bubbles
c. Floating scum and/or solids
d. Adequate ventilation of chlorine feeding room and storage area
e. NIOSH-approved 30 minute air pack
f. All standing chlorine cylinders chained in place
g. All personnel trained in the use of chlorine
h. Proper chlorine feed, storage, and reserve supply.
/A 19. Ultraviolet radiation di i fgc4on present and in use.
nt,
gr
20. Dechlorinat on: !�' � Utlet41..0
Yet 4) N/A a. Proper storage of sulfur dioxide cylinders
No . N/A b. Adequate ventilation of sulfur dioxide feeding room
Yes No N/A c. Automatic sulfur dioxide feed or feedback control operating
properly.
Yes rNQ N/A
Yes/Noj N/A
Yes i Ng N/A
Yes i No N/A
21. Aerobic Digester:
a. Excessive foaming in tank
b. Noxious odor
c. Mechanical aeration failure
d. Clogging of diffusers.

Page 4
22. Anaerobic Digester:
Yes No N/A ) a. Floating cover tilting
Yes No N/A / b. Gas burner operative
`\ 23. Sludge Drying and/or disposal: 4,
Yes No 'NtA. a. Poor sludge distribution on drying beds
Yes No N/A\ b. Vegetation in drying beds
Yes No N/A `, c. Dry sludge remaining in drying beds
Yes No N/A f d. Dry sludge stored on site
Yes No \N/A e. Filtrate from sludge drying beds returned to front of plant
Yes No N/ f. Sludge disposal through county landfill.
No 'N A g. Sludge land applied.
Yes No N/A `.
Yes No N/A
Yes No N/A /
Yes No \N/A/
Yes No
Yes No 'IN/
Yes No , N/
es \No N/A
Yes No N/A
Yes No N/A
24. Filter Press:
a. High level of solids in filtrate from filter presses or vacuum filters
b. Thin filter cake caused by poor dewatering
c. Sludge buildup on belts and/or rollers of filter press
d. Excessive moisture in belt filter press sludge cake.
25. Polishing Ponds or Tanks:
a. Objectionable odor, excessive foam, floating solids, or oil sheens on
water surface
b. Solids or scum accumulations in tank or at side of pond
c. Evidence of bypassed polishing ponds or tanks because of low
capacity.
26. Plant Effluent:
a. Excessive suspended solids, turbidity, foam, grease, scum, color, and
other macroscopic particulate matter present
b. Potential toxicity (dead fish, dead plant at discharge)
c. Outfall discharge line easily accessible.
27. Flow Measurement:
e N/A a. Proper placement of me surement device
e N/A b. Flow meter calibrate t % tv > tt \hic-e-ez--p-g-i,
Yes / N/A c. Buildup of solids in flume or weir
Yes d. Broken or cracked flume or weir
Yes /A, e. Clogged or broken stilling wells
Yes o 1 A f. Weir plate edge corroded or damaged
Yes o *A g. Flow measurement error less than 10%.

Page 5
28. Sampling:
No N/A a. Sampling and analysis completed on parameters specified by perniit
No N/A b. Composite sample temperatures maintained at 4 degrees Celsius or
less (but above freezing) during sampling
No N/A c. Contract laboratory used for sample analysis.
es ( N/A d. Effluent composite samples obtained are flow proportional. Wd/ D,-P
RECORDKEEPING AND REPORTING.
6s) No N/A 1. Records and reports maintained as required by permit.
Yes to N/A 2. All required information available, complete,and current.. apy-ez,
.{.�e�
Yes No /N/A) 3. Records mAa� tained for 3 years and all sludge records maifitained_for 5
years. /LiiU" /6' i IL)
Yes
Yes
Yes
Yes
N/A
No N/A
No N/A
No N/A
No N/A
No N/A
Yes No N/A
Yes ec23 N/A
4. Analytical results consistent with data reported on DMRs.
5. Sampling and analyses data adequate and include:
a. Dates, times, and location of sampling
b. Name of individual performing sampling
c. Results of analyses and calibration
d. Dates of analyses
e. Name of person performing analyses.
6. Monitoring records adequate and include:
a. Monitoring charts kept for 3 years
b: Flowmeter calibration records kept for 3 years.
,4ua Ova
No N/A 7. The pH meter is calibrated daily with two buffers and checked with a
third buffer and properly documented.
No N/A 8. Expiration dates of pH buffers adequate.
s N/A 9. All thermometers used in NPDES permit reporting is calibrated
annually with an NIST certified thermometer or a traceable
thermometer annually and documented.
211,1i? (id()
61.2)No N/A 10. ,follo i DES ermit_required para ers.are_analyzed on site:
-TT -- issolved Oxygen a hlorine Residua

Page 6
Yes No N/
Yes No
Yes No
Yes No N/A
No N/A
es No N/A
Yes No N/A
Yes No
No N/A
Yes N/A
The NPDES permit required parameter Total Chlorine Residual is
analyzed by approved method.
12. BOD incubator temperature maintained at 20 +/- 1 Degrees Celsius
and the temperature maintained in a log for every day of operation.
13. Fecal coliform incubator maintained at 44.5 +/- 0.2 Degree Celsius and
the temperature maintained in a log for every day of operation.
14. Plant records adequate and include:
a. O & M Manual
b. "As -built" engineering drawings
c. Schedules and dates of equipment maintenance repairs
d. Equipment data cards.
15. Permittee is meeting compliance schedule.
16. DMRs complete and include all NPDES permit required parameters.
17. The facility has a permitted flow greater than 5 MGD and is required
to operate seven days per week 24 hours a day.
Yes No N/A 18. ORC visitation logs available and current.
Yes No N/A 19. ORC certified at a level equal to or greater than the classification of
the wastewater facility.
No N/A 20. Backup Operator certified at one level less than the classification of
the wastewater facility or greater.
No N/A 21. Current copy of the complete NPDES permit on site.
Yes No N/A 22. Facility description verified as contained in NPDES pen -nit.
J
Yes No N/A ' 23. Facility analyzes process control parameters for example: MLSS,
MCRT, Settleable Solids and others that are applicable.
No N/A 24. Industrial Waste Surveys (IWS) sent to all possible Significant
Industrial Users (SIUs) within the last five years (especially new
industries).
Revised 7/16/01
by Belinda Henson

NCDENR/DIVISION OF WATER QUALITY
FAYETTEVILLE REGIONAL OFFICE
TELEPHONE:[phone]
FAX: [phone].
NPDES COMPLIANCE REMINDERS
1. The following NCDENR/DWQ units can be contacted for assistance:
Fayetteville Regional Office-910-486-1541 (NPDES and other information)
NCDENR 24 Hour Emergency-1-800-858-0368
Technical Assistance& Training-919 733 :3908 (free technical assistance and support)
Laboratory Certification-919733-3908(parameter'analyses_information)
Construction Grants & Loans-919 715-6212 (financial asistance)
Clean Water Management.Trust Fund-252-830-32
2. For Internet access the..NCDENR/,,Division o
uality webstte is as follows:
//h2d enr state nc us/ .
3. Permittees are required to request renewal -of a NPDES :permit at least 1
expirahori.
days prior to
4. The "Operator`in Responsible Charge(ORC)"'of a was tewater=treatinent facility must
have a valid certification with a grade equivalent to or greater than the classification
assigned to the wastewater treatment facility.
5. The "Backup Operator" of a wastewater treatment facility must have a valid
certification with no more than one grade less than the classification assigned to the
wastewater treatment facility.
6. All wastewater treatment operators with a valid certification must provide documentation
of a minimum of six (6) contact hours of Commission approved training each year.
7. The owner of the wastewater system must notify the Technical Assistance &
Certification Unit with a designation form for the ORC and Backup Operator for the
facility and also co -copy the regional office.
8. Flow meter devices which are used for reporting effluent discharges should be calibrated
annually with a maximum deviation of less than 10% from true discharge volumes.
The % error before and after calibration should be documented to calculate the maximum
deviation. All calibration records should be kept on site at the facility for at least three (3)
years. Stickers on flow meters do not satisfy necessary record keeping.

Page 2 of 5
9. All Discharge Monitoring Reports (DMRs) should be completed for each month and
received by Central Files no later than the 30th day following the completed reporting
period. The Original and One Copy of the DMR should be mailed to the following
address:
NC DENR
Division of Water Quality
Attn: Central Files
1617 Mail Service Center
;aleigh, NC 27699T,716.
10. In the event that you oiriit or erroneouslyreportt'data on a DMR, the information should
be updated with :the submittal ,of an amended report '
a) Regenerate or make a .copy from your files of theDMR previously submitted to
ou
DWQ .
b) Make changes.: to the individual data points on the form; including' updated
suinmary,inormation •:._
c) Initial and4highlight changes to the original submittal
d) At. the topfof the -reporting pages, write very conspicuously "Amended Copy" or
orrected Report".
e) Provide a short .cover {page descrbing the changes, to the DMR or note changes in
the comment area on''the backof the MR-1: form:,
11. As of October 1, 2001, facilities ormanagement. companies analyzing on -site field tests
for wastewater reporting purposes.of a classified facihtymust apply for certification status
as a Field Parameter Laboratory. Contact NCDENR/Laboratory Certification Section.at
919-733-3908 concerning applying for certification of field parameters. For Internet
access the website for the Laboratory Unit is www.dwglab.org.
12. Effective September 1, 2003 all facilities with mercury reporting requirements must
implement Method 1631( or subsequent low-level mercury methods approved by
EPA in 40 CFR 136) for mercury analysis for NPDES facilities. Facilities are subject to
this new requirement because either 1) your facility has a current total mercury limit in its
NPDES permit that is <0.20ug/1; or 2) your facility has limited instream dilution (i.e., the
instream waste concentration (IWC) is >6%).
13. All pollutants must be analyzed by, approved methods in labs certified by the
NCDENR/Laboratory Certification Section. The permit requirements must be reported
on the Discharge Monitoring Reports (DMRs). If an NPDES permit required parameter
is not reported on the DMR due to laboratory errors, exceeding holding time, and etc.
provide a written explanation on the back of the DMR or on an attachment.

Page 3 of 5
14. The permittee shall report by phone to our office within 24 hours of acknowledgment any
NPDES permit violations (daily, weekly or monthly).
15. The permittee shall report by phone to our office ASAP or no later than 24 hours of the
next working day when a process unit fails which will render the facility incapable of
adequate wastewater treatment such as mechanical or electrical failures of pumps,
aerators, etc. Persons reporting such occurrences by telephone shall also file a written
report in letter form within 5 (five) days following the first knowledge of the occurrence.
16. Composite samples s,houkt be rnautamed;at0 4`Degirees. Celsius during collection and
maintained for the entire sample period at"ttus tempe>ature urtil;they are analyzed. The
refrigerated sampler temperature should be documented when in use and checked with a
certified NISTithermometer annuall
17. All composite samplers should be:maintained by cleaning and replacing tubing as needed
to assure;the best quality samples to ensure NPDES compliance. -Tubing with algae or
slime growth can lead,;to NPDES permit lunit violations
18. The chlorine contact basin should be monitored and documented at least monthly (more
fre uentl �5if necessa for slud e de th b'' a slug e ud e I£the dep th is twelve 12
q Y rX) g P Y g J g ,p ( )
inches or More -it should be: cleaned immediately and the: sludge properly disposed of
Please note that some WWTP can=fail NPDES limits''due to accumulation of less than
twelve (12) inches. This is a upper recommended level (lower levels may need to be
maintained based on individual designs).
R K .
19. Process control analyses such as MLSKSludge Age„Settleability and etc. should be
performed and documented to assist in wasting solids from the system to develop
efficiency of the treatment of the wastewater which leads to NPDES permit compliance.
20. All Toxicity Reports should be mailed to the following address:
NC DENR
Division of Water Quality
Attn: Environmental Sciences Branch
1621 Mail Service Center
Raleigh, NC 27699

Page 4 of 5
21. The cleaning procedure for toxicity effluent composite sample containers is as follows:
- Step 1: Soap & water wash/Soak with a nonphosphate soap
((***soap should be laboratory grade soap (ex. Alconox), never use antibacterial
or other soaps not approved for laboratory use***))
- Step 2: Flush/Rinse twice with distilled water
-Step 3: Flush/Rinse with 10% nitric acid solution
- Step 4: FluslVRinse twice with distilled water
-Step 5: Flush/Rinse with dilute acetone
- Step 6: Flush/Rinse three times with.distilled water:,
- Step 7: Allow to dry .y.
- Step 8: Record in sample cleaning logboo
22. The Performance Annual Report must beaubrr fitted within 60 days.of the end of the
applicable 12 month review period It can be based on ac'alendar yeas or.:a fiscal year.
The report shouldbe submitted to the following address
ysterr ''Performance Annual Repor
orth'_Carolina D vision:;`of. Water Qualit
1617Mail Service -Center
Raleigh, NC27699-16
23. The Pretreatment Annual Reports are due March 1 (if required) for the period
January through December of,the;previous_.year. _ Al1,reports should be mailed to the
following address:
NC DENR
Division of Water Quality
Attn: Pretreatment Unit
1617 Mail Service Center
Raleigh, NC 27699-1617
24. The Pretreatment Program requires that a Public Notice be completed a minimum of
once per year in January or February for all Significant Noncompliant Industries
(SIUs) for the previous year and then include it in the PAR due March 1. An Industrial
Waste Survey (IWS) should be sent to industries every five years before the NPDES
permit renewals and also to assist with tracking SIUs both old and new.

Page 5 of 5
25. The State Annual Sludge Report is due March 1 for the period January through
December of the previous year. All reports should be mailed to the following address:
NC DENR
Division of Water Quality
Attn: Nondischarge Compliance Unit
1617 Mail Service Center
Raleigh, NC 27699-1617
26. The EPA Annual Sludge Report is_ due. February 19 for_the period January through
December of the previous year. All reports should be mailed'to the following address:
ector Danois;'Water Division
l5Courtland St. NE
tlanta, Georgia 30365
}x:
27. Any sewer spill regardless oft he volume that is -discharged into Waters of=State'and/or
any volume over 1,000 gallons must'be` reported to DWQ regional office All
wastewater/collection system owners or operator's, must issue a press release after a
discharge to surface waters of 1,000 gallons or more within 48 hours of first knowledge
of the spill,. If a"discharge of 15,000;gallons ormore reach''surface water, a public notice
is required in addition to the press release. If a discharge of 1,000,000'gallons of
wastewater or more reaches,surfacew.ers, the DWQ regional office must be contacted
to determine in what additional counties, ifany, a public notice must be published.
28. All records should be maintained for three (3) years and all sludge records maintained
for five (5) years.
29. As a suggestion facilities should periodically review the security measures implemented
at the plant site to prevent public access to hazardous chemicals or theft of these
materials.
Revised 9/3/02
by Belinda Henson

Introduction
eus arc the simplest, least expensive, and probably the most
common type of primary measuring device used to measure
flow in open channels. A weir is essentially an obstruction or dam built
across. an open channel over which the liquid flows, often through a
specially shaped opening or notch. Weirs arc normally classified
according to the shape of the notch. The most common types of weirs,•
as shown in. Figure 3-1; arc the rectangular weir, the V-notch (or trian-
gular) weir, and the trapezoidal (or Cipolletti) weir. Each type of weir
has an associated equation for determining the flow rate through the
weir. The equation is based on the depth of the liquid in the pool
formed upstream from the weir.
The edge or surface over which the liquid passes is called the crest
of the weir, as shown in Figure 3-2. (Note, that the V notch weir comes
to a point at the bottom, so it has no actual crest length; the point may
bethought of as the "crest" of a V notch weir.) Generally, the top edge
of the weir is thin or beveled with a sharp upstream corner so that the
A. Rectangular weir without
end contractions
C. V-notch (or triangular) weir
B. Rectangular weir with end
contractions_
D. Trapezoidal (or Cipolletti)
. weir
Figure 3-1: Various Sharp -crested Weir Profiles
26 • Weirs
Head
Measurement
Point
Maximum,Head, H
Nappe
Ventilation
Weir plate
„ del
Figure 3-2: Sharp -crested Weir
.liquid does not contact any part of the weir structure downstream but,
rather, springs past it. Weirs of this type are called sharp -crested weirs,,
and are discussed in this section. Broad -crested weirs are briefly dis-
cussed on pages 51-52.
The stream of water leaving the weir crest is called the nappe.
When the water surface downstream from the. weir is far, enough
'below the weir crest so that air flows freely beneath the nappe, the
nappe is aerated and the flow is referred to as free or critical. When the
downstream waterlevel rises to the point where air does not flow freely
beneath the nappe, the nappe is not ventilated and the discharge rate
may be inaccurate because of the low pressure beneath the nappc.
• When the downstream water level rises above the crest, the flow is
referred to as submerged or subcritical. This can affect the discharge
rate to a measurable degree, so dependable measurements should not
be expected in this range. Flow rate under submerged conditions can
be determined by measuring both the upstream and downstream levels,
:and referring to submerged flow tables. Submerged and nonventilated
E. flows are undesirable for standard conditions and should usually be
avoided. In most cases, weirs should be sized and installed to obtain
...ventilated and free or criticaldischarge conditions..
• Weirs • 27

The discharge rate of a wcir is determined by measuring the verti-
cal distance from the crest of the weir to the liquid surface in the pool
upstream from. the crest. This liquid depth is called the head. As
shown. in Figure 3-2, a slight drop in the liquid surface begins
upstream from the weir. This drop occurs at a distance of at least twice
the head on the crest, and is called the. surface contraction or draw -
down of the weir. To avoid sensing the effects of drawdown, the head
measuring point of the weir should be located upstream of the weir
crest a -distance of at least three, and preferably four times the maxi-
mum head expected over the weir, as shown in' Figure 3-2. Once the
head is known, the flow rate or discharge can' be determined using the
known head -flow rate relationship of the weir.
Thus, for a weir of a given size and shape with free -flow, steady-
state conditions and proper weir -to -pool relationships, only one depth
of liquid can exist in the upstream pool for a given discharge. A weir
may be thought of as a device for shaping the flow of the liquid to
allow a single depth reading that is uniquely related to a discharge rate.
Although weirs are comparatively easy to construct and convenient
to use, they arc not always suitable. Accurate flow rate measurements
cannot be expected unless the proper conditions and dimensions arc
maintained. Weirs are not .suitable for flat -sloped channel installations
where head loss must be considered. Weirs are also not suitable for
water carrying excessive solid materials or silt, which will deposit in the
approach channel behind the weir and destroy the conditions required
for accurate discharge measurement. Some silt, sand, or other solid
material will inevitably collect in any open channel flow system. To
allow the periodic removal of these deposits, it is suggested that the
weir bulkhead be constructed with an opening beneath the notch,
through which accumulations can be sluiccd.as required. A metal plate
or plank placed across the upstream side of this opening and securely
fixcd in place will serve as a cover while the weir is in operation.
lb ensure accurate discharge measurement, there are certain general
weir design requirements that apply to all types:
1. The weir should consist of a thin plate.'/8 to 'A inch (3 to 6 mm)
thick with a straight edge or a thicker. plate with a downstream
chamfered edge. The upstream sharp edge prevents the nappe
from adhering to the crest. Knife edges should beavoided
because they are difficult to maintain. However, the upstream
edge of the weir must besharp with right angle corners, since
rounded edges will decrease the head for a given flow rate.
2. The upstreatn face of the weir should be smooth and perpendicu-
lar to the axis of the channel in both horizontal and vertical direc-
tions. The crest of the weir should also be exactly level to insure a
uniform depth of flow.
3. The connection of the weir to the channel should be waterproof.
Therefore, the joint between the weir plate and channel should
be packed with chemically inert cement or asphalt type roofing
compound.
4. The length of the weir crcst or the notch angle must be accurately
determined, because the percentage error in measured flow rate
will be proportional to the error in determining these dimensions.
5. The wcir should be ventilated, if necessary, to prevent a vacuum
from forming on the underside of the nappe.
6. The height of the weir from the bottom of the channel to the crest
should be at least 2 times the maximum expected head of liquid
above the crest. This is necessary to lower the velocity of approach.
The weir height should never be less than 1 foot (0.3 m).
7. The approach section should be straight upstream from the weir
for a distance of at least 20 times the maximum expected head of
liquid, and should have little or no slope.
8. The crest must be set higher than the maximum downstream
elevation of the water surface. Otherwise, a submerged flow con-
dition will occur instead of the free flow condition required for
reliable flow measurement.
9. The device for measuring the head .(flow meter) should be placed
upstream at a distance of at Least 3 times the maximum expected
head on the weir and should be located in a quiet section of the
channel away from all disturbances, preferably in a stilling well.
Also, the zero point of the head measuring device must be set
exactly level with the weir crest.
28 • Weirs
Weirs • 29

10. The crest of the weir must be kept clean. Fibers, stringy materials,
and• larger particles tend to cling to the crest and should be
removed periodically. The upstream side of the weir should also
be periodically purged of accumulated silt and solids.
11: The weir size should be selected only after preliminary studies
have determined .the expected flow rates in the channel in ques
Lion. The Manning formula, as described in Chapter 6, can
sometimes be used to estimate the flow rate in open channels.
12. The cross -sectional area. of the approach channel .should be at.
least 8 .times that of die nappe at the crest for a distance upstream
of 15 to 20 times the head on the crest. This is necessary to mini-
mize the velocity of approach. The approach channel should also
. permit the liquid to approach the weir in a smooth stream•free
from turbulence, and the velocity should be uniformly distrib-
uted over the channel; this may be accomplished through the use
of baffle plates if necessary.
13. If die weir pool is smaller than defined by the above criteria, the
velocity of approach inay be too high and the head reading too
low. Refer to reference [1] for velocity of approach corrections.
•
Weirs should be installed and maintained to make the velocity of .
approach negligible. Appropriate corrections should be made
where this is not possible .
Weirs are classified in accordance with the shape of the notch or
opening in the weir. The basic types—V-notch, rectangular, and trape-
zoidal —are discussed individually, along with certain other types of weirs.
V notch. (triangular) weirs
The V notch or triangular sharp -crested weir (Figure 3-3) consists
of an angular notch cut into a bulkhead in the flow channel. The
apex of the notch .is at the bottom and the sidcs are set equally on
either side of a vertical line from the apex. The angle of the notch (a)
most commonly used is 90°, although V notch weirs with angles of
221/2° 30°, 45°, 60° and 120° are also used.
Some problems exist with narrow -angled V notch weirs. The small
included angle of these weirs makes it difficult to accurately produce;
tlic geometry of the weir at the apex. Also, the capillary effect will
30 • Weirs
restrict flow at a surprisingly high head, causing the head/discharge
relationship to be unreliable..
When installing a V-notch weir, the minimum distance of the sides
of the weir from the channel banks should be at least twice the maxi-
mum expected head on the weir. The minimum distance from the
crest to the pool bottom should also be at least twice the maximum
expected head. •
The V notch weir is. an accurate flow measuring device particular-
ly suited for low flows. Because the V-notch weir has no crest length,
the head required for a small flow through it is greater than that
required with other types of weirs. This is an advantage. for small
discharges in that the nappe will spring free of the crest, whereas it
would cling to the crest of another type of weir and reduce the accu-
racy of the measurement..
The V-notch weir is the best weir profile for measuring discharges
less than 1 cfs (450 gpm - 0.65 mgd - 28 1/s - 100.m3/hr) and has rea-
sonable accuracy for flows up to,10. cfs (45(Xgpm = 6.5 'mgd -. 280 Us '-
1.000 m3/hr). It is generally recommended that the minimum head on a
V notch weir be at least 0.2 foot (0.06 m) to prevent the nappe from
clinging to the crest. It is also recommended that the maximum head
2Hmax
minimum
Figure 3-3: V-notch (triangular) Sharp -crested Weir
Weirs • 31