wqcs00005_NOV-2020-DV-0502 Response_20201218

WATER MANAGEMENT
CITY OF DURHAM
December 11, 2020
Mr. Scott Vinson, Regional Supervisor
Water Quality Regional Operations Section
Raleigh Regional Office
NCDEQ, Division of Water Resources
3800 Barrett Drive
Raleigh, N.C. 27609
DEC It 2020
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NG DOR PakAgh Regions] OMOS
Subject: NOV-2020-DV-0502, Permit No. WQCS00005
City of Durham Collection System, Durham County
Dear Mr. Vinson,
This letter is in response to your notice dated November 16, 2020 which was received by the City of Durham on
November 25, 2020. The November 16, 2020 letter states that the City of Durham is provided an opportunity to
present evidence and justification to demonstrate that the proposed civil penalties for the Notice of Violation
(NOV) should not be assessed for the sanitary sewer overflows (SSOs) which occurred in the City's sewer collection
system between October 1, 2020 and October 31, 2020.
As requested, the City of Durham, Department of Water Management (DWM) is providing information about the
one incident which occurred during this timeframe which will support the City's position that despite meeting all
the conditions of the City's Collection System permit including site visits, inspections and easement maintenance,
these events were exceptional, unintentional, temporary and beyond the City's exercise of reasonable control.
DWM staff consider it is especially important to note that the attached map shows that the SSOs are dispersed
throughout Durham's service area.
Incident # 202002805 —1500 Ridgeway Avenue — October 18 2020
On October 181h, a manhole (#11146) at 1500 Ridgeway Avenue overflowed, with an estimated 410 gallons of
wastewater discharging into an unnamed tributary of Third Fork Creek. This overflow occurred due to a blockage
in the sewer main caused by grease from businesses and homes in the area. Water and Sewer Maintenance staff
used a high-pressure jet and vacuum to remove the blockage from the manhole, cleaning the lines above and
below with a jet truck. The creek was dammed and then flushed using a nearby hydrant (dechlorinated) and the
untreated wastewater was pumped back into the collection system.
The City's Stormwater Services Division responded and conducted ammonia testing to help determine the extent
of the spill and to advise when the site returned to normal conditions. No immediately visible adverse
environmental impacts or hazards to persons or property occurred.
City of Durham crews have followed up by cleaning the lines above and below the incident location and using CCTV
trucks. The City's FOG Program staff distributed notices to the neighborhood regarding proper grease, fats and oils
disposal options. This section of sewer line has been added to the Hot Spot program.
As required, a news release was issued within the 24-hour window. The cost to remediate this spill was $5,517.79.

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Ongoing City Wide Measures to Reduce the Occurrence of SSOs
The City has several programs in place to reduce and/or prevent the occurrence of SSOs. The City has
implemented a CMOM plan that expands and enhances its existing programs.
System Flushing and Inspection: The City routinely contracts flushing, CCTV inspection, smoke testing and
manhole inspections of portions of the sewer collection system. The City is completing the inspection of the
collection system systematically through City defined basins.
Additionally, the City ensures the requirements of the collection system permit are met by deploying City
crews to flush at least 10% of the collection system annually with a goal of exceeding the requirement by at
least 2 to 5% each year. The City measures the flushing on a fiscal year basis. For the FY 2021 year to date, the
City has cleaned 6.46% of the system. As operations normalize post-Covid-19, staff will dedicate more time to
this program.
Sewer Rehabilitation Program: The City has an active Sewer Rehabilitation Program. The program includes
flow monitoring (25 permanent monitors), CCTV inspection, manhole inspection, easement mowing, field
inspections and investigations, point repairs, line replacement, root and grease abatement and cured -in -place
manhole and line rehabilitation. There are 4 employee positions dedicated to the City's system rehabilitation
programs in the Utility Engineering Division of DWM. This workgroup handles flow monitoring and system
data management and contract preparation, administration and inspections. There are 21 employee positions
in our Collections Systems Maintenance workgroup in the Water & Sewer Maintenance (WSM) Division of
DWM. This group performs CCTV inspections, hydraulic cleaning activities, mowing and manhole inspection
and repair. They respond to blockages and overflows. WSM does contract inspections as well. In addition,
crews from the Main Line workgroup of WSM perform point repairs, line replacements and some cured -in -
place lining. The department established the Lift Station Maintenance Division in 2018 to focus oversight and
maintenance of the 65 lift stations throughout the service area and the 136 ARVs in the system. This 14-
member work group conducts the required daily/weekly inspections and associated preventive maintenance
activities. The City spends more than $5,000,000 on Sewer Rehabilitation projects annually as a part of its
Capital Improvements Programs.
Fat Oils and Grease Program (FOG): The department's FOG education and outreach effort is conducted by 3.0
FTEs (staff shared 50/50 with the Industrial Waste Control Program). In addition to working closely with the
Durham County Health Department, staff routinely inspect over 800 food service establishments (FSEs)
annually to ensure appropriate cleaning and maintenance of grease interceptors. Staff participates in a
number of community events —virtual and in -person when appropriate - to increase awareness of what is
appropriate to put in the sewer system. FOG staff conducts post-SSOs follow-up education and enforcement
as necessary. The City also invests more than $35,000 per year in advertising (TV commercials, social media,
etc.) regarding the proper disposal of FOG and nonwovens.
Summary:
Based upon the documented information provided above regarding these incidents, the City believes that
overflows were exceptional, unintentional, temporary and caused by factors beyond the City's/department's
reasonable control. The City actively manages, operates and maintains its system in such a manner as to meet all
the requirements of the Collection System permit. As detailed above, the City systematically inspects, flushes and
rehabilitates its wastewater collection system. The department works actively to educate the community
regarding what should and should not be discharged into the City's sewer collection system.

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Department staff welcomes the opportunity to meet with you and your staff to review our program and discuss
constructive ways to improve what we are already doing in the City of Durham. If you have any questions or need
any additional information please do not hesitate to contact me at [phone] or via email at
[e-mail].
Sincerely,
Donald F. Greeley, Director, PE,
Attachments
c: Jason Robinson, DEQ—Water Quality Regional Operations Section, Raleigh Regional Office
Junior Mobley, Superintendent, Water & Sewer Maintenance
Vicki Westbrook, Assistant Director
Jerry Morrone, Utility Engineering Manager, Sr.