WQCS00060_NOV-2019-DV-0392 Response_20191104

NC Dept of Environmental Quality
DEPARTMENT OF PUBLIC UTILITIES
POST OFFICE BOX 2263
SMITHFIELD, N.C. 27577
[phone]
November 4, 2019
Mr. Jay Zimmerman
Raleigh Regional Office
NCDEQ DWR
1628 Mail Service Center
Raleigh, NC 27699-1628
Re: Response to NOV-2019-DV-0392
Permit No. WQCS00060 - Johnston County Collection System
Dear Mr. Zimmerman:
V 12 2019
Raleigh Regional Office
In response to incident number 201901453 (1457 West Noble St, Selma), Johnston County offers the
following information:
• The facility located at 1457 West Noble Street is where the County receives wastewater from
the Town of Selma collection system and transmits flow to the County's system for treatment.
The spill was caused by excessive infiltration and inflow of rainwater into the Town of Selma's
wastewater collection system.
• The average daily flow for July 2018 through June 2019 received from the Town of Selma at this
site was 1.06 MGD. However, the County received more than 5.22 MGD over the 24-hour
period associated with Hurricane Dorian. The site has approximately 2.0 million gallons of flow
equalization for storage, and that storage capacity is not needed on a typical day. Based on our
records, the site received approximately 6.6 inches of rainfall from Hurricane Dorian.
• The County utilized all means necessary to equalize the flow received and pump to the
downstream facility in order to minimize the SSO.
• The spill occurred for approximately 440 minutes.
• All necessary material, personnel and equipment were available for clean-up. At the SSO site,
County staff vacuumed the sewer overflow from the spill area and lightly limed the area.
• The County has met with the Town of Selma to discuss the SSO and the volume of
inflow/infiltration into their collection system. The County has provided flow records to the
Town. Furthermore, County staff removed asphalt pieces from the influent screen at the site.
The volume of asphalt removed indicates that wastewater entered the system along streets that
may be or have been under construction and direct stormwater drain connections may be
contributing to the problem.
• The Town has taken multiple steps to identify and begin repairs to remediate the excessive
inflow and infiltration into their collection system. Please see the email from 1P McCann to Rick
Bolich dated October 25, 2019.
In response to incident number 201901478 (3146 Swift Creek Road, Smithfield), Johnston County offers
the following information:
• The spill was caused by a ductile iron pipe failure. The pipe failure appeared to be due to
internal corrosion from hydrogen sulfide in the force rain.
Printed on recycled papep TL4f

Page 2
Mr. Zimmerman
November 4, 2019
• The failed ductile iron pipe section connects the County's existing 12" and 20" force mains along
US 70. These force mains receive flow directly from eight wastewater pump stations. Pumper
trucks were used to pump and haul wastewater at several stations and the equalization basin at
Grifols was used to hold flow while the force main was shut -down to complete the repair. In
addition, some flow from Grifols and the County's Clayton K-5 wastewater pump station was
diverted into the Town of Clayton wastewater collection system while the force mains were
shut -down for repair. The County utilized all means necessary in order to minimize the initial
SSO and prevent additional potential SSOs while the force mains were shut -down for the repair.
• The repair required removal of the ductile iron section of pipe and replacement with PVC pipe.
In addition to County staff, the County had a licensed utility contractor on -site to assist with the
repair.
• All necessary material, personnel and equipment were available for clean-up and to complete
the pipe replacement. At the SSO site, County staff vacuumed the sewer overflow from the spill
area and lightly limed the area.
• The County has implemented a protocol to routinely monitor and inspect this force main route.
In response to incident number 201901485 (1457 Noble St, Selma), Johnston County offers the following
information:
• The spill was caused by a pipe failure on the site of the County's Selma WWPS and Equalization
Facility. This facility located at 1457 West Noble Street is where the County receives wastewater
from the Town of Selma collection system and transmits back to the County's system for
treatment.
• Please see the response to incident number 201901453 (above) for information related to the
excessive inflow and infiltration received at this site from the Town of Selma.
• The repair required removal and replacement of an approximate one foot section of cast iron
pipe.
• All necessary material, personnel and equipment were available for clean-up and to repair the
ARV. At the SSO site, County staff vacuumed the sewer overflow from the spill area and lightly
limed the area.
We have prepared our department to respond quickly to pipe and appurtenance failures by maintaining
an in-house supply of repair materials for all pipe sizes and implementing a detailed protocol for
emergency response. Furthermore, the County maintains a close working relationship with several local
contractors who provide emergency response repairs, as needed. Johnston County works aggressively
to prevent sanitary sewer overflows and help protect the waters of our area. Please contact meat
[phone] or [e-mail] if you have any questions or need additional
information regarding this issue.
Sincerely,
Cju,�� C.
Chandra C. Farmer, PE
Director of utilities
cc: Rick J. Hester, County Manager
Eric Narron
NC Dept of Environmental Quality
EOV 12 2619
Raleigh Regional Office
Mitchell Hayes, Raleigh Regional Office
Rick Bolich, Raleigh Regional Office