WQCS00002_NOV-2023-DV-0317_20230908

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Raleigh Water
September 8", 2023
Mr. Scott Vinson
Regional Supervisor
Water Quality Regional Operations Section
Raleigh Regional Office
Division of Water Resources NCDEQ
1628 Mail Service Center
Raleigh, NC 27699-1628
Re: Response to NOV-2023-DV-0317
Sanitary Sewer Overflows —July 2023
Permit No. WQCS00002
Dear Mr. Vinson:
NC Dept of Environmental Quality
SE. ;
Raleigh Regional Office
Please allow this letter to respond to the Notice of Violation document (NOV-2023-DV-0317) received on
August 21, 2023. This document contains the narrative regarding the pending Notice of Violation action of (1)
Sanitary Sewer Overflow (SSO) event, reported on the month of July 2023, within the City of Raleigh Collections
System Ill This document also provides exhibits as proof of our efforts to mitigate the sewer events. The noticed
events occurred while the City operated its collection system, according to WQCS00002, dated June 6, 2017. The
permit includes the language outlined in footnote 1 and applies to the SSOs upon which NOVs with the notice of
intent (NOV-N01) were based. This document will establish a reasonable explanation of the actions taken to stop
the spills, contain the released untreated wastewater, collect the wastewater and reintroduce it to the
collection system; and finally, restore the possible environmental impacts brought by the release of the SSO
events, listed with the intended NOV-NOI action. Please find below the additional information requested for the
SSO events.
1. "The Director may take enforcement action against the Permittee for SSOs that must be reported to the Division as
stipulated in Condition IV92). This includes SSOs that were caused by severe natural conditions or exceptional events
unless the Permittee demonstrates through properly signed, contemporaneous operating logs or other relevant
evidence that:
[a.] The s50 was caused by severe natural conditions; there were no feasible alternatives to the g50, such as the use of auxiliary treatment facilities, retention of
untreated wastewater, reduction of inflow and infiltration, use of adequate backup equipment, or an increase in the capacity of the system. This provision is not
satisfied if, in the exercise of reasonable engineering judgment, the Permittee should have installed auxiliary or additional collections system components, wastewater
retention or treatment facilities, adequate backup equipment, or should have reduced inflow and infiltration or
[b.j The SSO was exceptional, unintentional, temporary, and caused by factors beyond the reasonable control of the Permittee; the 550 could not have been prevented
by the exercise of reasonable control, such as proper management, operation, and maintenance;. adequate treatment or collection facilities or components (e.g.,
adequately enlarging treatment of collection facilities to accommodate growth or adequately controlling and preventing Infiltration and inflow[; preventative
maintenance; or installation of adequate backup equ 1pment;"

Incident Number # 202301127 - 7/31/2023 — 7900 Twin Oak Ct, Raleigh, NC, 27615
This spill was neither willful nor intentional. It resulted from a grease build-up, restricting the sewer flow within
a section of the 8-inch gravity sewer main. This build-up led to a sewer spill of approximately 940 gallons of
untreated wastewater, reaching an unnamed tributary within the Mine Basin. (See Exhibit 1—Area of
Operation)
On 7/31/23, at approximately 3:11 PM, Raleigh Water staff responded to a sanitary sewer overflow emanating
from a sanitary sewer manhole (SMH153031) near 7900 Twin Oak Ct, Raleigh, NC. The responding staff took all
reasonable steps to stop and mitigate the impact of the discharge, gaining control of the spill event by 4:45 PM
on the same day. Crews utilized hydraulic jetting to remove the source of the blockage within the affecting
asset, thus restoring sewer flow.
Containment and collection of this spill event consisted of employing a temporary containment site downstream
of the affected asset. This approach was intended to contain wastewater flow and minimize the environmental
impact on the surrounding land. Crews successfully contained a large amount of untreated wastewater before it
reached the state's surface waters, preventing further environmental pollution. Responding crews employed
pumps at the temporary containment site to recover flushed wastewater and any evidence of sewer completing
the operation by reintroducing the wastewater to the collection system. This spill was contained without a
significant environmental impact on the adjacent area and its natural resources. Visual inspection of the affected
area and downstream waters confirmed no fish kill or unnecessary vegetative damage.
During the restoration phase of the operation, crews utilized ample potable water to flush the affected area and
remove sewer traces from the surrounding area. The area around the manhole and containment area was
cleared of debris, treated with an application of lime, and restored with grass seed and straw.
A follow-up CCTV assessment was conducted on 08/7/2023 to identify the root cause of the SSO (See Exhibit 2 —
CCTV Assessment). Additional flushing of sewer gravity mains upstream and downstream of the affected asset
was completed on 8/9/2023. This hydraulic flushing did not identify any other major issues with the main.

Exhibit 2 — CCTV Assessment
The cost associated with the mitigation of this event amounted to $6,543.09. The approximate cost to the Utility
to have treated 940 gallons of wastewater would have been approximately $1.41. The City saved no money
from this spill. Its costs for cleanup exceeded the cost of treating the volume of sewage had no spill occurred.
Furthermore, the City still had to pay for treating the greater volume of sewage created by the spill.
This section of the collection system is located downstream of a residential area. It provides sewer collection
services to approximately 121 properties upstream of the spill event (see Exhibit 3- Zone of Influence). This
specific portion of the collection system has not experienced a grease -related SSO event. This area has been
placed under routine maintenance for continued assessment.
Outreach information literature was requested to be sent to the immediate affected area. The requested
outreach literature explains the need for customers to use the sanitary sewer collection system properly. It also
allows citizens to partner with Public Utilities to protect the City's water quality and sewer collection
infrastructure. See Exhibit 4 —Outreach Information

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Exhibit 4—Outreach Information
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audkey Ib sewaaemthepgr.
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eygene psomcel.
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, tmbwhbmlerpwmnrrmtall, b, wwally ldas,,su➢6ydhawwasrohlt
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Before this event, maintenance records show that sections within the zone of influence of this collection system
were assessed as follows:
Flushing activities CCTV Activities
6/28/2017 3/6/2017
6/29/2017 3/15/2017
2/21/2018
12/6/2022
Repair Activities
0
Inspections Activities
High Priority Inspections
completed in the area
1/22/2018
4/25/2018
4/16/2019
12/5/2022
No additional issues have been associated with this section of the collection system since the last sewer event.
This site continues to remain an active maintenance spot pending the completion of further sewer main cleaning
and chemical root control application.
4

Summary
The Sewer Maintenance Division of Raleigh Water strives to develop initiatives that improve operational
reliability to meet customer expectations and meet or exceed the Water Quality Collection System permit
requirements. Our operations are focused on continual improvement, the prevention of pollution, and increased
environmental performance efficiency. This endeavor is noted as the Division operates an ISO Certified
Environmental Management System governed by the 14001-2015 Standards. As part of these initiatives, the
Division operates a comprehensive reactive and preventive maintenance program to maintain over 2,644 miles
of sanitary sewer pipe and minimize the accidental release of untreated wastewater.
Since July 2022 (Fiscal Year 2023), the Utility has maintained approximately 936.95 [1i miles of gravity sewer
mains by flushing with hydraulic jetting, conducting CCTV assessments, and performing repair operations,
easement maintenance, and inspections. The fiscal year-to-date cost of these operations amounts to $
2,054,254.45 [2[, approximately 14% of the Division's annual operating budget. The 940 gallons of untreated
wastewater, identified as notice of violations in this letter, cost the Utility approximately $6,543.09 to mitigate.
The City's cost of sewer treatment per gallon is $.0015 [3]. At this rate, treating the untreated wastewater spilled
would cost the City $1.41. The City saved no money from these spills. The costs of mitigation well exceeded the
cost of treating the volume of sewage had no spill occurred.
Furthermore, the City still had to pay for treating the greater sewage volume created by these spills. This fiscal
comparison shows the City's commitment to environmental protection, sparing no cost regardless of the spill
incident's severity and complexity. The City continues demonstrating due diligence in environmental
performance by allocating resources to a spill incident regardless of the associated cost. This effort is noted in
the City's SSO performance rate of 1.15 total SSO rate [4[ per 100 miles of pipe, compared to the Southeastern
Region of the U.S., of 7.0 spills per 100 miles of line.
(1[ 936.95 miles represents approximately 36%of the entire sanitary sewer collection system
[2[ Associated operational cost year to date for FY2023
OPERATION
LINEAR FEET
Linear Miles
COST
CCTV
413,21L20
78.25
366,545.26
Repair
1,310
0.25
932,093.69
Flushing
1,836,732.38
347.8
624,65L96
Easement
459,360.00
87
130,963.54
Easement Inspections
2,236,890.12
426.65
N/A
The total cost of Business to
Total- 4,947,503.70
Ft/ 939.95 MILES
Date Is $2,054,254.45
(3) F.Y. 2023 annual DWisional budget - $24,657,701
[4[ $.0015 is based on the annual water treatment operating cost compounded by the total treated effluent.
[51 The current SSO Rate for F.Y. 23 is 1.15
Additionally, the City of Raleigh Assistant Public Utility Directors and Collections System staff have become
involved in challenging the nonwoven fabrics industry standards to better inform consumers of these products
and their detrimental effects on the collections systems. PUD staff has personally met with officers of INDA, the
leading association of the nonwoven fabrics industry based in Cary, NC, to communicate our concerns about
these fabrics, the current industry standards, and better education for the consumer. PUD has also joined forces
with other utilities nationwide through the National Association of Clean Waters Agencies (NACWA), the Water
Environment Foundation (WEF), and the American Public Works Association (APWA) to challenge INDA and
current industry standards, recognizing that they do not support compatibility in sanitary sewer collections
systems nationally. These agencies work collectively to challenge the testing protocols, assessment guidelines,
and consumer education and labeling of these non -dispersible.

Raleigh Water has an aggressive educational outreach initiative to address illicit discharges such as wipes, fats,
oil, and grease to commercial and residential users. Raleigh Water has developed a complimentary property
managers resource kit that provides best practice resources for establishing a property -specific awareness
program. Each kit contains brochures and complimentary gadgets to help residents manage grease and fat
collection and disposal. The resource kit also features a multimedia flash drive with videos and reproducible
educational material that property managers can use to educate tenants to reduce the risk of sewer backups
caused by the introduction of solids through their residential piping. Each kit costs Raleigh Water approximately
$85.00 to produce and is provided free of charge to the property management. Raleigh Water continuously
develops initiatives to increase residential and commercial customer partnerships to address grease
accumulation and prevent illicit incident discharges. The educational material and videos can be accessed
through social media and the Raleigh Water website: https:Hraleighnc.gov/sewer-maintenance
The City continues its monetary reward or bounty program, which pays out fifty ($50) to any citizen who
observes and reports an SSO or conditions that may cause a spill incident. This program has been advertised via
printed material, a television advertisement campaign, and graphic design "wraps" on Sewer Maintenance
vehicles. These graphics on our vehicles function as mobile billboards, spreading our prevention message and
offering contact information throughout the service area daily. This program was developed hoping that citizens
and customers would become more aware of the signs of an emerging system problem causing the SSO
occurrence and become proactive in helping the City prevent these occurrences. Additionally, all customers are
notified via their water and sewer utility bills not to discharge materials that could block the flow of the sanitary
sewer mains. The City also circulates information regarding grease discharge into the sewer system and the
effects of such deposits. Whenever possible, and upon investigating the root cause of a spill incident, PUD Code
Enforcement officers develop and send registered informational letters about the spill incident to the customer
base serviced by the line where the SSO has occurred. This is done to educate our customers on the proper use
of sanitary sewers to prevent the disposal of non-flushable items and items harmful to the continuous operation
of the collections system.
On behalf of the City of Raleigh, I am requesting that the NOV-2023-DV-0270 issued for the month of June 2023
be fairly reviewed, considering the steps the Department has taken to protect the environment and meet or
exceed the requirements of the Collections System Permit. If additional information is required, don't hesitate
to contact Matthew Vessie, Sewer Maintenance Superintendent, at [phone] or Carlos M. Perez, ORC,
Assistance Superintendent, at 919-996-5929.
QS �ely,
arl M Perez, ORC
Assistance Superintendent, Sewer Maintenance Division
City of Raleigh, Public Utilities Department
P.O. Box 590
Raleigh, NC 27602-0590
919-996-5929 office
919-278-6020 cell
Carlos.oerezcamacho@rat?a raleighnc.Gov