NC0025321_NOVNOI2020PC0171_RESP_20200427

Gavin Brown, Mayor
Gary Caldwell, Mayor Pro Tem
Jon Feichter, Alderman
Julia Freeman, Alderman
LeRoy Roberson, Alderman
4/27/2020
Mr. Landon Davidson, P.E., Regional Supervisor
Water Quality Regional Operations Section
Asheville Regional Office
Division of Water Resources, NCDEQ
2090 US Highway 70
Swannanoa, NC 28778
Robert W. Hites, Jr. Town Manager
William Cannon, Town Attorney
Water Quality Regional Operations
Asheville Regional Office
Re: Response to Notice of Violation & Intent to issue Civil Penalty
NOV-2020-PC-0171
Dear Mr. Davidson:
Thank you for providing the Town with an opportunity to respond to the Division's NOV
regarding the "Unauthorized Bypass" of 35,000 gallons of waste that occurred at our plant on
February 11, 2020 and 70,000 gallons on February 13, 2020. 1 will outline the event, our
immediate response and our plan to mitigate future overflows.
BYPASS OF BASIN BETWEEN PRIMARY CLARIFIERS AND EFFLUENT PUMP BLDG.
On February 10 and 11th, 2020 the water shed received 1.75 inches of rain. On the 13th it
received another 1.38 inches. The inflow entering the plant from these rain events exceeded the
plant's capacity to handle the flows. The overflows occurred at a "splitter basin" that resides
between the primary clarifiers and the effluent pump basin. The effluent pump basin contains
three pumps, each having a rated capacity of 3.0 gpd. During the rain events the pumps ran at
maximum capacity but could not keep up with the flow entering the plant. The increased flows
resulted in an overflow occurring in the splitter basin. McGill Engineering discovered that the
splitter basin has an elevation that is several inches below that of the effluent pump basin.
REMEDIATION OF BYPASS
The staff responded to the spill by raking and spreading lime in the area where the bypass
occurred. Some of the flows entered Richland Creek though no fish were killed as a result of
the overflow. The staff contacted McGill and Associates and requested that they determine if a
short- term solution could be determined. Keith Webb studied the "as built" construction
documents and determined that the elevation of the splitter basin located between the primary
clarifiers and the effluent pump basin was several inches below the rim of the effluent pump
basin. As flow increased due to inflow from the rain event it overflowed at that low point in the
plant. McGill recommended that the Town have a riser of 18 inches be added to the rim of the
splitter basin to bring it in line with the rim of the effluent pump basin. The riser was fabricated
and installed.
16 South Main Street • P.O. Box 100 • Waynesville, NC 28786 Phone [phone] Fax [phone]
Web Address: www.waynesvillenc.gov

Page 3.
NOV 2020-PC-0197
We hope that this explanation has provided you with the information you requested. Please let
us know if we can provide you with further information. We recognize that the overflow
constitutes a violation however we ask that you consider our immediate notification of the spill
and our efforts to mitigate the overflow.
Please do not hesitate to contact me at my cell number 828-550-5238 should you have any
questions:
Sincerely,
Robert W. Hites Jr. Town Manager
16 South Main Street • P.O. Box 100 • Waynesville, NC 28786 Phone [phone] Fox [phone]
Web Address: www.waynesvillenc.gov

IShaping Communities Together
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February 14, 2020
Jeff Stines, Interim Public Works Director
Town of Waynesville
Post Office Box 100
Waynesville, North Carolina 28786
RE: Sewer Overflow
Primary Clarifier Effluent Line
Dear Jeff:
Following our meeting on Wednesday with Mark, Jeff and Eric at the plant I took the information
I could obtain from the old drawings, discussions during the meeting and have reviewed the spill
instance at the plant. I understand that the plant experienced a spill out of the flow splitter box
downstream of the primary clarifiers. My review centers around how to possibly correct this
situation to reduce or eliminate the possibility of sewer overflows in this area.
There is an 18" effluent outlet pipe from each of the two primary clarifier throughs. These two
pipes join at a concrete splitter box. There are no record drawings of this box which show the
elevations (top or invert), and no indication of the invert of the pipe. A 30" DIP pipe conveys flow
from this splitter box to the wetwell for the intermediate pump station. Record drawings show the
invert of the 30" pipe into the wetwell at 2508.00. The top of wetwell is elevation 2515.00. 1
understand from Mark that during these high flow events the water level in the wetwell was 12" to
18" below the top of the wetwell. This of course resulted in overflow of the splitter box.
The immediate alternative to reduce the potential for the overflow is to raise the walls of the splitter
box. This can be accomplished by adding plate steel walls with support angles and attach to the
top of the box. These proposed walls should have a top elevation of 2519.5. This will match the
top wall of the primary clarifiers. The 30" pipe is properly sized to convey the 6.0 MGD average
daily flow as well as a peak flow of 12 MGD. However, when the water level in the intermediate
pump station reaches the 2514 elevation this results in the overflow at the subject splitter box. In
the next week or so we will field verify the top elevation of this box. In the mean -time the installation
steel walls to raise the elevation is recommended.
Please let me know if there are any questions.
Sincerely,
MCGIL ASSOCIATES, P.A.
M�Keith Webb, PE
Vice President
Cc: Rob Hites, Town of Waynesville
Mark Jones, Town of Waynesville
P:\2019\19.00330-VVaynesvilleNC-WWTP Upgrade Design & Cons\Correspondence\sewer overflow\Is 14feb20 primary darifier
MCGILL ASSOCIATES 55 BROAD STREET, ASHEVILLE, NC 28801 ' 828.252.0575 MGGILLASSOCIATES.COM