WQCS00060_NOV-2020-DV-0192 Response_20200512

i
POST OFFICE BOX 2263
SMITHFIELD, N.C. 27577
[phone]
May 12, 2020
Mr. Scott Vinson
Raleigh Regional Office
NCDENR Division of Water Resources
1628 Mail Service Center
Raleigh, NC 27699-1628
Re: Response to NOV-?_020-DV-0192
Incident No. 202000711
Permit No. WQC500060 -Johnston County Collection System
Dear Mr. Vinson:
In response to your letter dated April 30, 2020 (Incident number 202000711), we offer the following
information:
Incident and Response Information:
On February 18, 2020 at approximately 4:15 pm, County staff received an odor complaint on Cornwallis
Road. Staff immediately went to the area and located sewer leaking from an existing 12" force main
along Cornwallis Road. Staff shut-off the leak and diverted sewer into the existing 6" force main along
Cornwallis Road. In addition, the County contacted three private haulers to bring septic tank pumper
trucks to the upstream wastewater pump stations in the event the station could not maintain flow while
utilizing the smaller force main.
As excavation of the force main began, County staff secured a rental by-pass pump from Godwin Pumps.
A thorough investigation of the area, revealed that the wastewater was contained in a wooded naturally
low-lying area next to Swift Creek. County staff further "bermed" the area at the lowest points to
ensure any spilled wastewater would remain contained in this area and not flow to Swift Creek. This
allowed the wastewater to be fully contained within the low-lying area. The flow did not overtop the
area and enter Swift Creek.
County staff completed the force main repair with a repair band over the small hole that was evident in
the DIP. Then, staff put the rental by-pass pump into operation at approximately 10:00 pm, pumping
wastewater, rainwater and standing water from the low-lying area back into the County's collection
system for transmission and treatment. County staff operated the pump excavating all water from the
area. Staff recovered approximately 315,000 gallons and pumped the recovered water back into the
County's collection system. No wastewater entered directly into Swift Creek from this break, and staff
lightly limed the low-lying area that contained the sewer after the water was pumped back into the
collection system for treatment.
Printed on recycled paper

Page 2
May 12, 2020
Mr. Vinson
Cause of Pipe Failure,
The force main pipe failure was located on a section of ductile iron pipe. It appeared to be a result of
corrosion. The County requires Protecto 401 or Sewper Coat on the interior of ductile iron material
installed as part of the sewer system. This can be field verified during construction by identification of a
red band painted on the end of the joints of pipe that contain the interior coating.
After a similar pipe failure in this area in 2017, the County verified that the ductile iron pipe was coated
on the interior. Also, in 2017, Wes Sheffield from US Pipe (pipe manufacturer) inspected the failed pipe
and confirmed that the pipe did contain the interior coating. He believed that the corrosion started
from the outside. Further investigation revealed that Colonial Pipeline had a cathodic protection cable
in the vicinity of the pipe failure. Although the existing petroleum main is over 1,000 LF from the spill
site, this was the only explanation for exterior corrosion of the pipe. After the repair in 2017, the
County visually inspected the surrounding DIP, conducted high-pressure operation with inspection and
continued to monitor the area on a routine basis (sonic detection and visual inspection).
Additional Permanent Repair and Mitigation Measures:
This failure occurred on a section of ductile iron pipe installed as a transition from SDR-21 PVC to a HDPE
directional drill. The County prepared an emergency contract to replace all existing DIP on the existing
6" and existing 12" force mains in this vicinity along Cornwallis Road. County staff distributed the
contract to bidders on February 21, 2020, and received bids on February 27, 2020. The contract
included the following:
• Removal of 180 LF of 6" DIP and replacement with 6" C-900 PVC
• Removal of 180 LF of 12" DIP and replacement with 12" C-900 PVC
• Removal of 2-6" DIP to HDPE connections and replacement with 2-6" PVC to HDPE connections
• Removal of 2-12" DIP to HDPE connections and replacement with 242" PVC to HDPE
connections
• Connection between the 6" and 12" force mains for redundancy in the event of future
emergency or failure
• Replacement of a pump connection in the event of future emergency or failure.
The total removal and replacement contract cost was $54,715.25, and work was completed on April 3,
2020.
The County's estimated total cost for clean-up and repairs associated with this pipe failure and repair
are as follows:
• Immediate Repair and Clean-up:
o Tanker Costs = $14,950.00
o Pump Rental = $10,565939
o Materials = $720000
o Value of County Labor = $6,300.00
o Total Immediate Repair Costs= $32,353.39
• DIP Removal and Replacement with PVC - KBS Construction, Inc. _ $54,715.25
• Total Clean-up and Immediate/Long Term Repairs = $87,068.64

Page 3
May 12, 2020
Mr. Vinson
The County has updated our construction and design standards, and the updated standards eliminate
and/or minimize the use of DIP within the County's collection system.
The Johnston County Department of Utilities is prepared to respond quickly to pipe failures by
maintaining an in-house supply of repair materials for all pipe sizes and implementing a detailed
protocol for emergency response. In addition, employees are trained to fully understand the County's
system and interconnections with other utilities and utilize any potential redundancy within the system.
For example, in this case, staff temporarily diverted wastewater into a parallel force main, which is part
A the County's system and some flow regularly (as needed) pumps to the Town of Clayton for
treatment.
Johnston County works aggressively to prevent sanitary sewer overflows and help protect the waters of
our area. Unfortunately, pipe failures are very difficult to predict or prevent. Including this pipeline
removal and replacement, the County has replaced at least 5 problematic force mains in the last 13
years where failures were recurrent.
Please contact me at [phone] or [e-mail] if you have any questions or
need additional information regarding this issue.
Sincerely,
Chandra C. Farmer, PE
Director of Utilities
cc: Rick J. Hester, County Manager
Vanessa Manuel (via email only)
Mitch Hayes (via email only)
Eric Narron