WQCS00005_RSP_NOV-2022-DV-0177_20220720

WATER MANAGEMENT
CITY OF DURHAM
July 19, 2022
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
Subject: NOV-2022-DV-0177; Permit No. WQCS00005
Dated: June 22, 2022; Received: July 6, 2022
City of Durham Collection System, Durham County
Dear Mr. Vinson,
NC Dept of Environmental Quality
JUL 20 2022
Raleigh Regional Office
The above referenced 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 (SSO) which occurred in the City's sewer collection system between May
1, 2022 and May 31, 2022.
As requested, the City of Durham, Department of Water Management (DWM) is providing information about the
two requested incidents that occurred during this timeframe to support the City's position that these events were
exceptional, unintentional, temporary, and beyond the City's exercise of reasonable control despite meeting all the
conditions of the City's Collection System permit including system cleaning, site visits, inspections, and easement
maintenance.
Incident #202200695 —1107 Lancaster Drive - May 2. 2022
On May 2, 2022 at 6:25 pm, an overflow occurred near 1107 Lancaster Drive releasing an estimated 2,500 gallons
of wastewater into South Ellerbe Creek. Crews discovered that grease and roots were the cause of the blockage
and used a JetVac truck to successfully clear the line. After assessing the extent of the spill, crews dammed the
downstream creek with sandbags, set up a 4-inch pump to re-route the untreated wastewater back into the
collection system, and flushed the area using a nearby hydrant (dechlorinated water). Crews then used a JetVac
truck to clean the three upstream and three downstream pipe reaches to ensure the pipes were clear.
The City's Stormwater Services Division responded and conducted ammonia testing to confirm the spill's extent
and advise when the site returned to normal conditions. No immediately visible adverse environmental impacts or
hazards to persons or property were observed.
This section of gravity main has been scheduled for replacement in July 2022 to remediate the existing root
intrusion. To address the grease accumulation within the sewer lines, the department's Industrial Waste
Control/FOG staff distributed educational material on the proper disposal of fats, oils, and grease to customers in
the area. In addition, the indicated series of reaches were added to the City's Hot Spot program and will be
checked by CCTV truck on periodic basis.
As required, a news release was issued within the 24-hour window. The cost to date to remediate this spill was
$5,464.87.

Page 2 of 3
Incident #202200727 - 633 Eastway Avenue - May 6 2022
On May 6, 2022 at 4:43 pm, an overflow occurred near 633 Eastway Avenue releasing an estimated 1,270 gallons
of wastewater into a tributary of Goose Creek. Crews discovered that grease was the cause of the blockage and
used a 1etVac truck to successfully clear the line. After assessing the extent of the spill, crews dammed the
downstream creek with sandbags, set up a 4-inch pump to re-route the untreated wastewater back into the
collection system, and flushed the area using a nearby hydrant (dechlorinated water). Crews then used a JetVac
truck to clean the three upstream and three downstream pipe reaches to ensure the pipes were clear.
The City's Stormwater Services Division responded and conducted ammonia testing to confirm the spill's extent
and advise when the site returned to normal conditions. No immediately visible adverse environmental impacts or
hazards to persons or property were observed.
The department's Industrial Waste Control/FOG staff distributed educational material on the proper disposal of
fats, oils, and grease to customers in the area. The indicated series of reaches were added to the City's Hot Spot
program and will be checked by CCTV truck on periodic basis. During the remediation efforts, a sag in the main
segment was observed and the segment of main has been sent to the City's point repair contract for replacement.
WSM crews have scheduled additional follow up cleaning activities for the three upstream and three downstream
pipe reaches at the incident location to ensure the pipes remain clear. As required, a news release was issued
within the 24-hour window. The cost to remediate this spill was $6,582.14.
Ongoing City -Wide Measures to Reduce the Occurrence of SSOs
The City has several programs in place to prevent and reduce 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 cleaning, CCTV inspection, smoke testing, and
manhole inspections of portions of the sewer collection system. The City completes the inspection of the
collection system systematically based City defined geographical basins.
The City ensures the requirements of the collection system permit are met by deploying City crews to clean 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 cleaning on a fiscal year basis starting July 1. As of May 31, 2022, 12.5% of the
City's collection system has been cleaned by City staff and contractors.
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 four full-time equivalents (FTEs) employees 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
20 FTEs in the City's Collections Systems Maintenance workgroup in the Water and Sewer Maintenance (WSM)
Division of DWM. This group performs CCTV inspections, hydraulic cleaning activities, mowing, manhole
inspections, and manhole repairs. They respond to all reported concerns including blockages and overflows. In
addition, the CSM crews are supported by the Excavation Services workgroup of WSM who perform identified
point repairs, line replacements, and cured -in -place lining.

Page 3 of 3
In 2018, the department established the Lift Station Maintenance Division to focus on oversight and
maintenance of the 65 lift stations throughout the service area and the 136 ARVs in the system. This 18 FTE
workgroup conducts required daily and 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.
Fats, Oils, and Grease Program_(FOG): The department's FOG education and outreach effort are
conducted by three 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 several community events, such as Earth Day, Center Fest, and
Landlord Workshops, as well as neighborhood meetings to increase awareness of the proper disposal
of waste and the impact on the wastewater system. FOG staff conducts post-SSO follow-up education
and enforcement as necessary. The City also invests more than $35,000 per year in advertising the
proper disposal of FOG on television, social media, and other media avenues.
Summary:
Based upon the documented information provided above regarding these incidents, the City believes that these
SSOs were exceptional, unintentional, temporary, and caused by factors beyond the City and Department's
reasonable control. The City actively manages, operates, and maintains its system in such a manner as to meet or
exceed all the requirements of the Collection System permit. As detailed above, the City systematically inspects,
flushes, and rehabilitates its wastewater collection system. The Department actively works to educate the
community regarding what should and should not be discharged into the City's sewer collection system.
The 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, PLS
Attachments
c: Jason Robinson, DEQ— Water Quality Regional Operations Section, Raleigh Regional Office
Junior Mobley, Superintendent, Water & Sewer Maintenance
Vicki Westbrook, Assistant Director
Scott Smart, Assistant Director
Jerry Morrone, Utility Engineering Manager, Sr.

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