DEQp00022081

DIVISION OF ENVIRONMENTAL MANAGEMENT
December 4, 1989
MEMORANDUM
TO: Don Safrit, Supervisor
Permits & Engineering do • _
�"� x '.• :. is
FROM: M. J. Noland, RegionaI-,�upervi_gr
Fayetteville Regional Office,
SUBJECT: NPDES Permit No. NCQO03573 �-
AC0003573
Authorization to Construct
E. I. du Pont de Nemours & Company
Fayetteville Plant
Bladen County
The subject Authorization is being requested so that Biopond sludge can
be properly prepared for shipment at an approved landfill site in Pinewood,
South Carolina.
The proposed facility consists of the following:
Thickening:
Excess waste sludge is taken from the waste treatment clarifiers recycle
stream and fed to a Dissolved Air Floatation Thickener (DAF), where the solids
are concentrated to a nominal 3% from 0.5%. The DAF effluent is pumped to the
Digester, where it is held until it is pumped to sludge dewatering. The
Digester is an existing concrete lined basin that was previously used as the
biological treatment aeration basin prior to 1989.
Dewatering:
The thickened sludge is mixed with a commercial coagulant aid, and is
then pumped to a Pre -Thickener, followed by a Screw Press where the solids are
concentrated to a nominal 8%. The dewatering system filtrate is returned to
�. «.
the waste treatment equalization tank. _ ._.•-•
A standard belt conveyor is used t
y o transport the dewater
intermediate 2,200 -gallon sludge holdup vessel and then con
system. ✓� _
19�
j
T?�?- copy'
s,

Mr. Don Safrit
Page 2
December 4, 1989
Drying:
Sludge drying is accomplished by using a steam heated dryer to boil off
about 707 of the water in the waste sludge. A blower is used to pull water
vapor from the dryer to the direct water spray type scrubber. The scrubber
collected water effluent is returned to the waste treatment equalization tank.
The dry sludge, nominal 267 solids, is conveyed to the landfill con-
tainer.
0 Landf i 11
When a landfill container is full, about 22,000 lbs., it is then shipped
to the approved landfill, which is currently the GSX landfill in Pinewood,
South Carolina.
The proposed facility will consist of three major commercially available
sludge handling units connected in a series. This sequential treatment will
generate a suitably landfillable sludge. The equipment will be centrally
housed in one building and all filtrates and water streams discharge back to
the headwaters of the company's wastewater treatment plant. The proposed
sludge handling facility will not affect existing outfalls and no changes are
requested for discharge parameters.
It is the recommendation of this office that the Authorization to
Construct for the proposed sludge handling facilities be processed and the
appropriate nAuthorization issued.
MJN/GD/tf'J
7
c (gat'_ 1
DEC 12 1$$9
..;CfiNTRAL FiLE.COFY