NC0025984_NOV-2018-PC-0418 Response_20190211

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February 11, 2019
Town of Forest City
PO Box 728
Forest City, NC 28043
Attn: Landon Davidson, P.G., Regional Supervisor
Water Quality Regional Operations Section
Asheville Regional Office
Division of Water Resources, NCDEQ
SUBJECT: NOV-2018-PC-0418
Unauthorized Bypass
Permit No. NCO025984
County: Rutherford
Mr. Davidson,
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The Town of Forest City WWTP experienced Inflow and Infiltration issues associated with 4.8 inches of
rain recorded at the sewer plant from Hurricane Michael. As stated in the 5 day report the spill/bypass
occurred at the splitter box located behind the aerator grit/grease chamber. Flow backed up in the
headworks and spillage would occur as the RAS pump, which discharges upstream of this box, cycled on.
No MLSS reached surface waters. The aeration basin aerators were off and sludge was not in the
clarifiers at this time. During heavy I&I this is a standard practice to not "sludge" the river. Once we
realized how this was occurring the RAS was diverted to a downstream splitter box closer to the large
aeration basin. The spillage was over estimated to account for what the flow chart demonstrated and the
potential for an operator to miss a pump run cycle.
Corrective actions are to more closely monitor this location in our plant when heavy rain occurs. Myself
and Jeff Dotson are now on the Bracket Creek call out list for high level situations, and we are working
closer with our pump maintenance department during storm events. When the emergency Godwin pump
is pumping and if other stations are at high level stage during such storms we are now notified. During
high level events either myself or a backup operator will monitor the box in question for the duration of
the peak flow event and manually open the slide gate to send flow into an unused aeration tank (aeration
tank #1) as necessary to not spill at this location. Our plan is to budget (2019-2020) for core drilling and
run a ductile iron pipe to the unused basin directly so this can occur automatically and be monitored as
necessary by plant operators. This pipe will be open at all times inside the splitter box at an elevated level
so only peak flow from storm events will flow into the basin. The unused basin was a primary clarifier in
the 1980s' before being converted to an aeration basin (# 1).. This basin sits adjacent to a 2-cell
rectangular aeration tank (Aeration Basin #2 and #3) also not in service. We also plan to request in
budget year 2019-2020 for the 2-cell aeration tanks to operate in series with the unused aeration #1 as
flow equalization basins while not in service for increased capacity. They will then be pumped out at a
more convenient time when flow returns to normal. Our Pump Maintenance and Sewer Departments
have placed portable ISCO flow meters (provided by McGill & Associates) in locations to try and track
down some of the heavy I&I locations.
The graphs on page 2 of this letter are from the USGS Second Broad River monitoring station near
Logan, NC. The graphs depict precipitation, discharge, and gage height for the period of October 7, 2018
through October 21, 2018 and confirm the plants rain gage reading for the storm period.
PO Box 728 Forest City, NC 28043 Telephone [phone] Fax [phone]
Email address: [e-mail]
Visit our website
www.townofforesteity.com

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USGS 02150495
SECOND
BROAD RIVER MR LOGAN, MC
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07
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2018 2018
2018
201O 2818 2818 2818
— Precipitation
® Period of approved data
Graph c ..... eF the U.S. Geeieg Leal S—
USGS 02150495 SECOND
BROAD RIVER MR LOGOM, MC
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m
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Oct
Oct Oct
Oct
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2818
2818 2818
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---- Provisional Data
Subject to Revision ----
Median daily statistic
C28 years)
— Discharge
Graph a urte3r eF the U.S. G..2..jc.L S_
USGS 82150495
SECOND
BROAD RIVER MR LOGAN, NC
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Oct
Oct Oct Oct Oct
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09 11
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2018 2018
2018
2018 2818 2818 2B1$
---- Provisional Data
Subject to Revision ----
— Gage height
Operational linit Cnlnlnun)
Graph c —+.esa of the U.S. Geological S_V
PO Box 728 Forest City, NC 28043 Telephone [phone] Fax [phone]
Email address: [e-mail]
Visit our website
www.townofforesteity.com

Town of Forest City
PO Box 728 +
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as
PVC line was for dryer condenser water discharge and Dryer exhaust
gas from sludge chamber to draw into odor scrubber. This line will
be removed and a ductile pipe installed with a 90-degree bend to
extend up and with a pipe addition. The level will be set so discharge
can gravity over to the unused aeration tank only during period of
high level. In the case of overflow this appears to be when the RAS
pump runs which discharges into the splitter box above this location.
This is the normal operating level of the splitter under normal
conditions.
Circular basin (Aeration #1) location from splitter box. Slide gate in
shot is the gate to manually bypass to this location. The core drill
will allow for automatic gravity bypass as needed for the flow in
excess only allowing for increased capacity during storm events. We
are confident this budget request has merit for approval.
Aeration # 1 was originally designed as a primary clarifier. We are
going to request for budget to repair the discharge box and run a
gravity line to the splitter for the square basins (aeration #2 and #3)
which can be seen in the background of this image.
PO Box 728 Forest City, NC 28043 Telephone [phone] Fax [phone]
Email address: Son nyPenson�`tow nofforestcitv.com
Visit our website
www.townofforestcity.com

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Town of Forest City o�
PO Box 728 ;+'I� +
Forest City, NC 28043 yogT'`.�P
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Larger images of the above referenced will be included with this mailing along with an image of
the flow chart for that week and a map downloaded from WRAL weather found on Facebook
depicting rainfall totals from Michael for North Carolina sourced by the National Weather
Service.
If you or any of your staff have additional questions, comments, or requests for information
please let me know.
Sincerely,
Sonny enson
Chief Operator
Cc: Jeff Dotson, Superintendent
John Condrey, City Manager
Enclosures
PO Box 728 Forest City, NC 28043 Telephone [phone] Fax [phone]
Email address: SonnyPensonCtownofforestcity.com
Visit our website
www.townofforesteity.com

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28 Forest City, NC 28043 Telephone [phone] Fax [phone]
Email address: SonnyPenson(altownofforestcit}.com
Visit our website
www.townoffurestcity.com

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PO Box 728 Forest City, NC 28043 Telephone [phone] Fax [phone]
Email address: [e-mail]
Visit our website
www.townofforesteity.com

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PO Box 728 Forest City, NC 28043 Telephone [phone] Fax [phone]
Email address; SonnyPensonOtow nofforestcity.com
Visit our website
www.townofforesteity.com

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