NC0025054_Compliance Evalution Inspection_20230531

DocuSign Envelope ID: 054E4EE6-B9C6-438D-9591-8DEA5395210E
ROY COOPER
Governor
ELIZABETH S. BISER
Secretary
RICHARD E. ROGERS, JR.
Director
Ms. Amy Ratliff, City Engineer
City of Oxford
PO Box 506
Oxford, NC 27565
NORTH CAROLINA
Environmental Quality
May 30, 2023
Subject: Compliance Evaluation Inspection
Oxford WWTP
NPDES Permit No. NCO025054
Granville County
Dear Ms. Ratliff:
On March 21, 2023, Cheng Zhang of the Raleigh Regional Office (RRO) conducted a compliance
evaluation inspection of the subject facility. The assistance provided by Mr. Antoine Lewis, the
operator in responsible charge (ORC), was greatly appreciated as it facilitated the inspection process.
The inspection report is attached. The following observations were made:
Oxford WWTP is permitted to discharge at a rate of 3.5 MGD and consists of manual and automatic
bar screens; mechanical aerated grit collector; influent Parshall flume; influent flow meter; influent
pump station with three (3)submersible pumps; equalization pump station; one (1) one million gallon
equalization tank; two (2) — oxidation ditches featuring anaerobic, anoxic, and aerobic zones with
each oxidation ditch equipped with two surface aerators and two submersible mixers providing
nutrient reduction using BioDenipho process; three (3) — secondary clarifiers; three traveling bridge
type sand filters; dual ultra violet disinfection; post aeration; effluent Parshall flume; effluent flow
meter; two (2) — Return Activated Sludge (RAS) pump stations; three (3) — aerated digesters two at
400,000 gallons each and one at 280,00 gallons; two (2) — thickened sludge storage lagoons at 2 MG
each; 800 KW on -site generator for power generation. The facility discharges into Fishing Creek,
which is classified C, NSW waters in the Tar -Pamlico River Basin.
1. The current permit became effective April 1, 2021 and will expire September 30, 2025.
2. At the time of inspection, the automatic bar screens and grit collector were operating normally.
All three influent pump stations were online. Both aerators were in operation in two oxidation
ditches. Solids content in the ditches are kept at approximately 2900 mg/1 and DO is around 2.4
mg/l. Foam covered approximately 30% of the surface area. Color of the influent was medium
chocolate brown. All three secondary clarifiers were in operation; sludge blanket in the number
one clarifier was 2.1 feet; number two was 2.6 foot; and number three was 0.3 feet. All
secondary clarifiers have 14-feet side wall depth. Effluent flowing off the weirs appeared clear.
The 1 MG EQ tank was empty. All digesters were about half full. One thickened sludge lagoon
was approximately half full. The other sludge lagoon was empty. The traveling bridge sand
D � � North Carolina Department of Environmental Quality I Division of Water Resources
Raleigh Regional Office I 3800 BarrettDrive I Raleigh, North Carolina 27609
NORTH CAROLINA ^ 919.791.4200
0�, ,mo E,Amnme lU-IR,

DocuSign Envelope ID: 054E4EE6-B9C6-438D-9591-8DEA5395210E
filters were operating normally. Effluent in the clear well appeared clear. Both banks of UV were
operational. Effluent at the outfall was mixing in with the creek with no negative effects.
3. The ORC maintains a daily logbook. Lab results, chain -of -custody forms, and DMRs were
complete and current, kept in good order and ready for review. July and December 2022 DMR
data were compared to lab bench sheets; no data transcription errors were noted. Influent and
effluent flow meters were calibrated annually.
4. The right of way to the outfall was well maintained. No visible impacts were noted immediately
downstream of the effluent pipe.
5. Field lab parameter (Certificate No. 5696) calibration and analysis records were reviewed during
the inspection. Please add field lab to the Certified Laboratory list on the DMR.
If you have any questions regarding the attached reports or any of the findings, please contact Cheng
Zhang at: [phone] (or email: cheng zhang&ncdenr.gov).
Sincerely,
DocuSigned by:
E
aun Sa. f.
9C4F04ECDE594A1...
Vanessa E. Manuel, Assistant Regional Supervisor
Water Quality Regional Operations Section
Raleigh Regional Office
Division of Water Resources, NCDEQ
Attachment(s): EPA Water Compliance Inspection Report
Cc: Laserfiche
Antoine Lewis, City of Oxford (Electronic copy only)
D � ��� North Carolina Department of Environmental Quality I Division of Water Resources
512 North Salisbury Street 1 1611 Mail Service Center I Raleigh, North Carolina 27699-1611
NORTH CAROLINA ��` 919.707.9000
enpn .mo EnWromm�nfal nual

DocuSign Envelope ID: 054E4EE6-B9C6-438D-9591-8DEA5395210E
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
1 IN 1 2 u 3 I NC0025054 111 121 23/03/21 I17 18 I C I 19 Ls_] 201 I
211111 I I I I I I II I I I I I I I I I I I I I I I I I I I I I I I II I I I I I r6
Inspection
Work Days Facility Self -Monitoring Evaluation Rating B1 QA ---------------------- Reserved -------------------
67
I 72 I ni I 71 I 74 79 I I I I I I I80
701 I 71 I LL J I I
LJ
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 Dermit Number)
01:OOPM 23/03/21
21/04/01
Oxford WWTP
325 New Commerce Dr
Exit Time/Date
Permit Expiration Date
Oxford NC 27565
03:OOPM 23/03/21
25/09/30
Name(s) of Onsite Representative(s)/Titles(s)/Phone and Fax Number(s)
Other Facility Data
Antoine L Lewis/Superintendent/919-693-8783 /
Antoine Lamont Lewis/ORC/919-693-8783/
Name, Address of Responsible Official/Title/Phone and Fax Number
Contacted
Amy Ratliff, ///
No
Section C: Areas Evaluated During Inspection (Check only those areas evaluated)
Permit 0 Flow Measurement Operations & Maintenar Records/Reports
Self -Monitoring Progran 0 Sludge Handling Dispo: Facility Site Review Effluent/Receiving Wate
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
cusignedby: DWR/RRO WQ/919-791-4200/
5/30/2023
Cheng Zhang E,1,71508E1EC41F
...
Signature of Management Q A Reviewer Agency/Office/Phone and Fax Numbers Date
DocuSigned by:
5/30/2023
Vaun t,SSa f, hci t VALL
"--9c4F04 E 9 1.
EPA Form 398$-� (ftev 9-94) Previous editions are obsolete.
Page#

DocuSign Envelope ID: 054E4EE6-B9C6-438D-9591-8DEA5395210E
NPDES yr/mo/day Inspection Type (Cont.)
NCO025054 I11 12I 23/03/21 117 18 i c i
Section D: Summary of Finding/Comments (Attach additional sheets of narrative and checklists as necessary)
The current permit became effective April 1, 2021 and will expire September 30, 2025.
The 3.5 MGD facility consists of the following units: manual and automatic bar screens; mechanical
aerated grit collector; influent Parshall flume; influent flow meter; influent pump station with three
(3)submersible pumps; equalization pump station; one (1) one million gallon equalization tank; two (2)
— oxidation ditches featuring anaerobic, anoxic, and aerobic zones with each oxidation ditch equipped
with two surface aerators and two submersible mixers providing nutrient reduction using BioDenipho
process; three (3) — secondary clarifiers; three traveling bridge type sand filters; dual ultra violet
disinfection; post aeration; effluent Parshall flume; effluent flow meter; two (2) — Return Activated
Sludge (RAS) pump stations; three (3) — aerated digesters two at 400,000 gallons
each and one at 280,00 gallons; two (2) — thickened sludge storage lagoons at 2 MG each; 800 KW
on -site generator for power generation.
At the time of inspection, the automatic bar screens and grit collector were operating normally. All
three influent pump stations were on line. Both aerators were in operation in two oxidation ditches.
Solids content in the ditches are kept at approximately 2900 mg/I and DO is around 2.4 mg/I. Foam
covered approximately 30% of the surface area. Color of the influent was medium chocolate brown.
All three secondary clarifiers were in operation; sludge blanket in the number one clarifier was 2.1
feet; number two was 2.6 foot; and number three was 0.3 feet. All secondary clarifiers have 14-feet
side wall depth. Effluent flowing off the weirs appeared clear. The 1 MG EQ tank was empty. All
digester were about half full. One thickened sludge lagoon was approximately'/2 full. The other sludge
lagoon was empty. The traveling bridge sandfilter was operating normally. Effluent in the clearwell
appeared clear. Both banks of UV were operational. Effluent at the outfall was mixing in with the creek
with no negative effects.
Discharge Monitoring Reports for the review period August 2019 through February 2023 were
reviewed
for compliance for permit limits and monitoring requirements. No violations were noted.
Commercial lab results, chain of custody records, and bench sheets were compared with data
submitted on the DMR for July and December 2022. No discrepancies were noted. Oxford WWTP
laboratory
analyses fecal coliform, pH, total suspended solids, and dissolved oxygen. All other permit
parameters are analyzed by Meritech Environmental Laboratories Inc.
The laboratory was checked in a cursory manner. All instruments, meters, probes, photometric cells
are maintained in good condition. Temperatures on all equipment are checked against an NIST
thermometer. All standards, reagents and consumables used are within expiration dates.
Page#

DocuSign Envelope ID: 054E4EE6-B9C6-438D-9591-8DEA5395210E
Permit: NCO025054 Owner -Facility: Oxford WWTP
Inspection Date: 03/21/2023 Inspection Type: Compliance Evaluation
Operations & Maintenance Yes No NA NE
Is the plant generally clean with acceptable housekeeping? 0 ❑ ❑ ❑
Does the facility analyze process control parameters, for ex: MLSS, MCRT, Settleable ❑ ❑ ❑
Solids, pH, DO, Sludge Judge, and other that are applicable?
Comment: Facility analyzes MLSS, settleable solids, nitrate, ammonia, sludge blankets, and
others for process control
Permit
Yes No NA NE
(If the present permit expires in 6 months or less). Has the permittee submitted a new
❑
❑
■
❑
application?
Is the facility as described in the permit?
■
❑
❑
❑
# Are there any special conditions for the permit?
0
❑
❑
❑
Is access to the plant site restricted to the general public?
0
❑
❑
❑
Is the inspector granted access to all areas for inspection?
■
❑
❑
❑
Comment: The current permit became effective April 1, 2021 and will expire September 30, 2025
Flow Measurement - Influent
# Is flow meter used for reporting?
Is flow meter calibrated annually?
Is the flow meter operational?
(If units are separated) Does the chart recorder match the flow meter?
Comment: Last calibrated on 2/21/2023
Pump Station - Influent
Is the pump wet well free of bypass lines or structures?
Is the wet well free of excessive grease?
Are all pumps present?
Are all pumps operable?
Are float controls operable?
Is SCADA telemetry available and operational?
Is audible and visual alarm available and operational?
Yes No NA NE
❑ ■ ❑ ❑
• ❑ ❑ ❑
• ❑ ❑ ❑
❑ ❑ ■ ❑
Yes No NA NE
• ❑ ❑ ❑
• ❑ ❑ ❑
• ❑ ❑ ❑
• ❑ ❑ ❑
• ❑ ❑ ❑
• ❑ ❑ ❑
• ❑ ❑ ❑
Comment: Three influent pumps to pump influent to oxidition ditches; two pumps for pumping
influent to EQ basin
Q c,.. ---
Type of bar screen
Yes No NA NE
Page# 3

DocuSign Envelope ID: 054E4EE6-B9C6-438D-9591-8DEA5395210E
Permit: NCO025054 Owner -Facility: Oxford WWTP
Inspection Date: 03/21/2023 Inspection Type: Compliance Evaluation
Bar Screens Yes No NA NE
a.Manual
❑
b.Mechanical
Are the bars adequately screening debris?
0
❑
❑
❑
Is the screen free of excessive debris?
0
❑
❑
❑
Is disposal of screening in compliance?
0
❑
❑
❑
Is the unit in good condition?
0
❑
❑
❑
Comment:
Grit Removal
Yes
No
NA
NE
Type of grit removal
a.Manual
❑
b.Mechanical
Is the grit free of excessive organic matter?
0
❑
❑
❑
Is the grit free of excessive odor?
■
❑
❑
❑
# Is disposal of grit in compliance?
■
❑
❑
❑
Comment:
Equalization Basins
Yes
No
NA NE
Is the basin aerated?
❑
0
❑
❑
Is the basin free of bypass lines or structures to the natural environment?
M
❑
❑
❑
Is the basin free of excessive grease?
0
❑
❑
❑
Are all pumps present?
■
❑
❑
❑
Are all pumps operable?
■
❑
❑
❑
Are float controls operable?
0
❑
❑
❑
Are audible and visual alarms operable?
❑
❑
❑
# Is basin size/volume adequate?
0
❑
❑
❑
Comment: The EQ basin is mainly used to hold leachate from a land fill, and during high flow
events. It was empty at the day of inspection
Oxidation Ditches
Are the aerators operational?
Are the aerators free of excessive solids build up?
# Is the foam the proper color for the treatment process?
Yes
No
NA NE
■
❑
❑
❑
•
❑
❑
❑
•
❑
❑
❑
Page# 4

DocuSign Envelope ID: 054E4EE6-B9C6-438D-9591-8DEA5395210E
Permit: NCO025054 Owner -Facility:
Oxford WWTP
Inspection Date: 03/21/2023 Inspection Type:
Compliance Evaluation
Oxidation Ditches
Yes
No
NA
NE
Does the foam cover less than 25% of the basin's surface?
0
❑
❑
❑
Is the DO level acceptable?
0
❑
❑
❑
Are settleometer results acceptable (> 30 minutes)?
0
❑
❑
❑
Is the DO level acceptable?(1.0 to 3.0 mg/I)
0
❑
❑
❑
Are settelometer results acceptable?(400 to 800 ml/I in 30 minutes)
M
❑
❑
❑
Comment: two (2) — oxidation ditches with each oxidation ditch equipped
with two surface aerators
and two submersible mixers providing nutrient reduction using BioDenipho process
(with anaerobic, anoxic, and aerobic zones)
Nutrient Removal
# Is total nitrogen removal required?
# Is total phosphorous removal required?
Type
# Is chemical feed required to sustain process?
Is nutrient removal process operating properly?
Comment: Chemical feed is not needed to sustain nutrient removal
Secondary Clarifier
Is the clarifier free of black and odorous wastewater?
Is the site free of excessive buildup of solids in center well of circular clarifier?
Are weirs level?
Is the site free of weir blockage?
Is the site free of evidence of short-circuiting?
Is scum removal adequate?
Is the site free of excessive floating sludge?
Is the drive unit operational?
Is the return rate acceptable (low turbulence)?
Is the overflow clear of excessive solids/pin floc?
Is the sludge blanket level acceptable? (Approximately'/4 of the sidewall depth)
Comment: sludge blankets were 0.3, 2.1, and 2.6 feet at three clarifiers (14 feet deep)
Pumps-RAS-WAS
Are pumps in place?
Are pumps operational?
Yes No NA NE
•
❑
❑
❑
•
❑
❑
❑
Biological
❑
■
❑
❑
■
❑
❑
❑
Yes No NA NE
• ❑ ❑ ❑
• ❑ ❑ ❑
• ❑ ❑ ❑
• ❑ ❑ ❑
• ❑ ❑ ❑
• ❑ ❑ ❑
• ❑ ❑ ❑
• ❑ ❑ ❑
■ ❑ ❑ ❑
■ ❑ ❑ ❑
■ ❑ ❑ ❑
Yes
No
NA NE
■
■
❑
❑
❑
❑
❑
❑
Page# 5

DocuSign Envelope ID: 054E4EE6-B9C6-438D-9591-8DEA5395210E
Permit: NCO025054 Owner -Facility: Oxford WWTP
Inspection Date: 03/21/2023 Inspection Type: Compliance Evaluation
Pumps-RAS-WAS Yes No NA NE
Are there adequate spare parts and supplies on site? ■ ❑ ❑ ❑
Comment:
Filtration (High Rate Tertiary)
Yes
No
NA
NE
Type of operation:
Down flow
Is the filter media present?
■
❑
❑
❑
Is the filter surface free of clogging?
■
❑
❑
❑
Is the filter free of growth?
■
❑
❑
❑
Is the air scour operational?
■
❑
❑
❑
Is the scouring acceptable?
■
❑
❑
❑
Is the clear well free of excessive solids and filter media?
■
❑
❑
❑
Comment:
Disinfection - UV
Yes
No
NA
NE
Are extra UV bulbs available on site?
■
❑
❑
❑
Are UV bulbs clean?
■
❑
❑
❑
Is UV intensity adequate?
■
❑
❑
❑
Is transmittance at or above designed level?
■
❑
❑
❑
Is there a backup system on site?
■
❑
❑
❑
Is effluent clear and free of solids?
■
❑
❑
❑
Comment: Two UV banks in series
Influent Sampling
Yes
No
NA
NE
# Is composite sampling flow proportional?
■
❑
❑
❑
Is sample collected above side streams?
■
❑
❑
❑
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 Celsius)?
Is sampling performed according to the permit?
■
❑
❑
❑
Comment:
Effluent Sampling Yes No NA NE
Page# 6

DocuSign Envelope ID: 054E4EE6-B9C6-438D-9591-8DEA5395210E
Permit: NCO025054 Owner -Facility: Oxford WWTP
Inspection Date: 03/21/2023 Inspection Type: Compliance Evaluation
Effluent Sampling
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 Celsius)?
Is the facility sampling performed as required by the permit (frequency, sampling type
representative)?
Comment:
Flow Measurement - Effluent
# Is flow meter used for reporting?
Is flow meter calibrated annually?
Is the flow meter operational?
(If units are separated) Does the chart recorder match the flow meter?
Comment: Last calibrated on 2/21/2023
Effluent Pipe
Is right of way to the outfall properly maintained?
Are the receiving water free of foam other than trace amounts and other debris?
If effluent (diffuser pipes are required) are they operating properly?
Comment:
Yes
No
NA
NE
❑
❑
❑
❑
❑
❑
❑
❑
❑
❑
❑
❑
❑
❑
❑
❑
❑
❑
Yes No NA NE
❑ ❑ ❑
❑ ❑ ❑
❑ ❑ ❑
❑ ❑ ■ ❑
Yes No NA NE
❑ ❑ ❑
❑ ❑ ❑
❑ ❑ ❑
Upstream / Downstream Sampling Yes No NA NE
Is the facility sampling performed as required by the permit (frequency, sampling type, 0 ❑ ❑ ❑
and sampling location)?
Comment: Member of Tar Pamlico Basin Association
Laboratory
Yes
No
NA
NE
Are field parameters performed by certified personnel or laboratory?
0
❑
❑
❑
Are all other parameters(excluding field parameters) performed by a certified lab?
0
❑
❑
❑
# Is the facility using a contract lab?
0
❑
❑
❑
# Is proper temperature set for sample storage (kept at less than or equal to 6.0
0
❑
❑
❑
degrees Celsius)?
Incubator (Fecal Coliform) set to 44.5 degrees Celsius+/- 0.2 degrees?
❑
❑
0
❑
Page# 7

DocuSign Envelope ID: 054E4EE6-B9C6-438D-9591-8DEA5395210E
Permit: NCO025054 Owner -Facility: Oxford WWTP
Inspection Date: 03/21/2023 Inspection Type: Compliance Evaluation
Laboratory Yes No NA NE
Incubator (BOD) set to 20.0 degrees Celsius +/- 1.0 degrees? ❑ ❑ ■ ❑
Comment: Facility has Field Lab Certification # 5696, is certified to analyze field parameters
(temperature, DO, and PH)
Record Keeping
Yes
No
NA
NE
Are records kept and maintained as required by the permit?
■
❑
❑
❑
Is all required information readily available, complete and current?
■
❑
❑
❑
Are all records maintained for 3 years (lab. reg. required 5 years)?
■
❑
❑
❑
Are analytical results consistent with data reported on DMRs?
■
❑
❑
❑
Is the chain -of -custody complete?
■
❑
❑
❑
Dates, times and location of sampling
■
Name of individual performing the sampling
■
Results of analysis and calibration
■
Dates of analysis
■
Name of person performing analyses
■
Transported COCs
■
Are DMRs complete: do they include all permit parameters?
■
❑
❑
❑
Has the facility submitted its annual compliance report to users and DWQ?
■
❑
❑
❑
(If the facility is = or > 5 MGD permitted flow) Do they operate 24/7 with a certified
❑
❑
■
❑
operator on each shift?
Is the ORC visitation log available and current?
■
❑
❑
❑
Is the ORC certified at grade equal to or higher than the facility classification?
■
❑
❑
❑
Is the backup operator certified at one grade less or greater than the facility
■
❑
❑
❑
classification?
Is a copy of the current NPDES permit available on site?
■
❑
❑
❑
Facility has copy of previous year's Annual Report on file for review?
■
❑
❑
❑
Comment:
Aerobic Digester
Yes
No
NA
NE
Is the capacity adequate?
■
❑
❑
❑
Is the mixing adequate?
■
❑
❑
❑
Is the site free of excessive foaming in the tank?
■
❑
❑
❑
# Is the odor acceptable?
■
❑
❑
❑
# Is tankage available for properly waste sludge?
■
❑
❑
❑
Page# 8

DocuSign Envelope ID: 054E4EE6-B9C6-438D-9591-8DEA5395210E
Permit: NC0025054 Owner -Facility: Oxford WWTP
Inspection Date: 03/21/2023 Inspection Type: Compliance Evaluation
Aerobic Digester Yes No NA NE
Comment: Three digesters with plenty of space for wasting sludge
Standby Power
Yes
No
NA
NE
Is automatically activated standby power available?
0
❑
❑
❑
Is the generator tested by interrupting primary power source?
0
❑
❑
❑
Is the generator tested under load?
■
❑
❑
❑
Was generator tested & operational during the inspection?
0
❑
❑
❑
Do the generator(s) have adequate capacity to operate the entire wastewater site?
0
❑
❑
❑
Is there an emergency agreement with a fuel vendor for extended run on back-up
0
❑
❑
❑
power?
Is the generator fuel level monitored?
■
❑
❑
❑
Comment: Generator is tested under load weekl
Lagoons
Yes
No
NA
NE
Type of lagoons?
Facultative
# Number of lagoons in operation at time of visit?
2
Are lagoons operated in?
Parallel
# Is a re -circulation line present?
❑
❑
0
❑
Is lagoon free of excessive floating materials?
0
❑
❑
❑
# Are baffles between ponds or effluent baffles adjustable?
❑
❑
■
❑
Are dike slopes clear of woody vegetation?
0
❑
❑
❑
Are weeds controlled around the edge of the lagoon?
0
❑
❑
❑
Are dikes free of seepage?
0
❑
❑
❑
Are dikes free of erosion?
■
❑
❑
❑
Are dikes free of burrowing animals?
0
❑
❑
❑
# Has the sludge blanket in the lagoon (s) been measured periodically in multiple
❑
❑
0
❑
locations?
# If excessive algae is present, has barley straw been used to help control the growth? ❑ ❑ 0 ❑
Is the lagoon surface free of weeds? ■ ❑ ❑ ❑
Is the lagoon free of short circuiting? 0 ❑ ❑ ❑
Comment: Two 2 million -gallon concrete sludge lagoon to hold final sludge before being hauled
away
Page# 9