WQCS00005_NOV-2023-DV-0004 Rsp_20230131

WATER MANAGEMENT
CITY OF DURHAM
City of Durham
Department of Water Management
1100 Martin Luther King Jr Parkway
Durham, NC 27707
919-560-4344
January 31, 2023
Mr. Scott Vinson, Regional Supervisor
Water Quality Regional Operations Section
Raleigh Regional Office
NCDEQ, Division of Water Resources
3800 Barrett Drive
Raleigh, NC 27609
Subject: NOV-2023-DV-0004 Permit No. WQCS00005
Dated: January 9, 2023; Received: January 18, 2023
City of Durham Collection System, Durham County
Dear Mr. Vinson,
NC Dept of Environmental Quality
JAN 3 1 {!
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 overflow (SSO) which occurred in the City's sewer collection system between
December 1, 2022 and December 31, 2022.
For the purposes of supporting the City's position that these events were exceptional, unintentional, temporary,
and beyond its reasonable control, the Durham Department of Water Management (DWM) is providing
information about the requested incidents that occurred during this timeframe. All conditions of the City's
Collection System permit are met by the Department, including system cleaning, site visits, inspections, and
easement maintenance.
Incident#202201768 -1101 Hamlin Road — December 2, 2022
On December 2, 2022 at 9:02 AM, an overflow occurred near 1101 Hamlin Road releasing an estimated 14,400
gallons of wastewater into a tributary of Ellerbe Creek. It was found that a contractor working at the Wastewater
Treatment Plant isolated a headwork's valve causing increased line pressures that ultimately caused a failure in a
force main. Once notified, staff at the plant reverted valve positioning reestablishing flows to the treatment plant.
After assessing the extent of the spill, crews dammed the downstream creek with sandbags, set up a 4-inch pump
to pump the untreated wastewater back into the collection system, and flushed the area using a nearby hydrant
(dechlorinated water). The City had identified a area of the force main in need of replacement. (This area
included the section where the failure occurred.) We immediately hired an engineering consulting firm to
perform the replacement design. The City has an $8.3 Million construction contract underway replacing the force
main in this area, the contract was awarded in November 2022 and is approximately 25% complete.
Unfortunately, the failure occurred in a section not yet started.

The City's Stormwater Services Division responded and conducted ammonia testing to help determine 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.
A news release was issued within a 24-hour window. The cost to remediate this spill was $5,189.33.
Incidenttt202201788 - 3124 Medford Road - December 9.2022
On December 9, 2022 3:54 PM, an overflow occurred near 3124 Medford Road releasing an estimated 695 gallons
of wastewater into a body of water or tributary of Ellerbe Creek. Crews identified debris in line was 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 pump the untreated wastewater back into
the collection system, and flushed the area using a nearby hydrant (dechlorinated water). Crews used a JetVac
truck to clean the three upstream and three downstream pipe reaches to ensure the pipes in the area were clear
and followed up by CCTVing the lines. Staff also inspected the nearby manholes per MACP standards.
The City's Stormwater Services Division responded and conducted ammonia testing to help determine the spill's
extent and advise the Department 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 program staff responded to this event with an approximate 120
mailings and 250 non -woven door hanger packets, and visited one multi family home to educate the residents on
the effects of grease in the collection system and inform them of appropriate disposal options.
Staff will continue to monitor this reach of the collection system for issues on a periodic basis. Staff have identified
the main for remediation due to condition and age and it has been placed on the current slip -lining contract
managed by the Department's Utility Engineering team.
A news release was issued within a 24-hour window. The cost to remediate this spill was $10,464.38.
Oneoine 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
Collection System Management, Operations & Maintenance (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 on 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 2% to 5%each year.
The City measures the cleaning on a fiscal year basis starting July 1. As of December 31, 2022, 3.1% of the
City's collection system had 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
21 FTEs in the City's Collections Systems Maintenance (CSM) 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. In 2018, the department
established the Lift Station Maintenance Division (LSM) to focus on oversight and maintenance of the 63 lift
stations throughout the service area and the 136 air relief valves (ARVs) in the system. This workgroup of 21
FTEs conducts required daily, weekly, monthly, and annual 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 is conducted by
three FTEs (staff shared between the Industrial Pretreatment, Septage and FOG Programs). In addition to
working 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
participate in several community events, such as Earth Day, Center Fest and Bimbe, as well as neighborhood
meetings. Department staff deliver residential Fat Trappers to increase awareness of the proper disposal
methods for waste. FOG staff also conducts post-SSO follow-up education and enforcement as necessary. The
City invests over $50,000 per year in advertising the proper disposal of FOG on television. Staff post to the
City's quarterly newsletter, The Durham Digest, along with multiple mentions in the City Manager's Report
known as City Connect, to reach a broad range of Durham residents.
Summary:
Based upon the documented information provided above regarding these incidents, the City believes that these
SSO's were exceptional, unintentional, temporary, and caused by factors beyond the City and Department's
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 also 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
Don.GreeleyC)durhamnc.poy,
Sincerely,
Donald F. Greeley
Director
Attachments

Cc Jason Robinson, DEQ—Water Quality Regional Operations Section, Raleigh Regional Office
Junior Mobley, Superintendent, Water & Sewer Maintenance
Scott Smart, Assistant Director
Jerry Morrone, Utility Engineering Manager, Sr.