WQCSD0704_NOV-2020-DV-0462 Additional Response_20201116

11-12-2020
SANITARY SEWER
OVERFLOW
RESULTING FROM DEFICIENCIES IN
ROANOKE RAPIDS SANITARY DISTRICT
COLLECTION SYSTEM
Chris Williams
Environmental Engineer
November 16, 2020

RR MILL SANITARY
SEWER SYSTEM
OVERVIEW

RR MILL SANITARY SEWER SYSTEM OVERVIEW
■ Rain events of 4.5" on September 18, 2020 and 5.75" on November 12, 2020 resulted in backing up of the
RRSD sewer line due to inability to handle excess flows and created an overflow on WestRock mill property
that resulted in notifications to State agencies.
■ The Sanitary Sewer Collection System is separate from the Mill's Process Sewer and discharges to Roanoke
Rapids Sanitary District at MH 113.
■ Head pressure and Manhole elevations cause overflows on Mill property when levels in MH 113 rise due to
restrictions and/or excessive volume in the RRSD system.
■ Placement of plastic and sandbags on the Mill site only moves the overflow to other areas of WestRock's
property. Extensive covering of manholes causes bathrooms in the Security Guard shack and contractor lot
bathrooms to overflow, creating a need to close those facilities and relocate the Security Guard.
■ Volume from mill sanitary sewer into RRSD sewer has not increased to contribute to this issue.
■ WestRock inspected its entire sanitary sewer line in July 2020 using a robotic camera and found it to be in
good condition.
3
WestRock

RR MILL SANITARY SEWER SYSTEM OVERVIEW
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4 WestRock

OVERFLOW ACTION TAKEN M H 109 - M H 112
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WestRock

FURTHEST UPSTREAM OVERFLOW TO STORMWATER IN MILL'S SYSTEM — MH 106
yr 3$ . 'I,. %"
MH 106 during overflow event
MH 106 after plastic and
sandbag placement
WestRock

RR SANITARY DISTRICT
ROOT CAUSE OF
OVERFLOWS ON
WESTROCK PROPERTY

RRSD ROOT CAUSE FOR OUR OVERFLOWS
Approximate RRSD Service Area for Sewer Line on WestRock Property
WestRock

RRSD ROOT CAUSE FOR OUR OVERFLOWS
Water level in MH 113 during normal operating conditions. This photo was taken when we repaired
our tie-in to the RRSD sewer in February 2020.
WestRock

RRSD ROOT CAUSE FOR OUR OVERFLOWS
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Water level in
MH
113
at time of our overflows. This is where our sanitary sewer collection
system ties in
with
the
Roanoke Rapids Sanitary District system.
WestRock

WestRock