time will recomputed by calculating the volume of the separation zone
within the separator and dividing this volume by the design flow rate. For
computing detention time, total volume shall be reduced by 20% for the
space occupied by settled solids (sediment) and accumulated oil at the
surface.
2.4.2
Parallel Plates
Provide parallel plates at an angle from 0.70 to 1.05 rad 40 to 60 degrees
with respect to longitudinal axis of the plate corrugations and space not
less than 19 mm 3/4 inch apart for removal of free oil and settleable
solids. Configuration used shall not promote solids buildup on plates
which would increase velocities to point of discharging an effluent of
unacceptable quality. Maintain laminar flow at maximum design flow rate
throughout plate packs including entrance and exit so as to prevent
re-entrainment of oil(s) with water. Flow through plate packs shall be in
a downflow mode parallel to plate corrugations or cross-flow perpendicular
to plate corrugations, so that the oil collects and coalesces at high point
of corrugations and rises to top of pack without clogging from oil or
settleable solids. Make minimum effective projected surface area [
]square feet ([ ]square meters).
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NOTE: Vertical tube coalescers shall not be used on
Army projects
**************************************************************************
[2.4.3
Vertical Tubes
If vertical tubes are provided, install tubes perpendicular to bottom of
tank and align in a pattern to maintain laminar flow at maximum design flow
rate through tube packs including entrance and exit to prevent emulsifying
the oil(s) with water. Inlet to tube packs shall prevent hydraulic
short-circuiting of oil-in-water mixture across the top of the tubes.
]2.4.4
Supports
Brace and support individual plates [and tubes] or plate packs [and tube
packs] to withstand loads associated with transportation and operation of
units, including inplace cleaning. Equip each plate [or tube] pack with
lifting lugs or other attachments for handling and installation. Each lug
shall carry total weight of plate pack [or tube pack]. Provide adequate
structural supports to facilitate inplace cleaning of plate pack [or tube]
bundles.
2.4.5
Baffles
Provide oil retention baffle, adjustable surface oil overflow weir with
trough, and stationary underflow baffle. Position underflow baffle to
prevent resuspension of solids that have accumulated in secondary solids
hopper.
2.5
OUTLET COMPARTMENT
Provide outlet compartment of [_____] cubic feet cubic meter, an adjustable
overflow effluent weir, a sampling port, and nozzles.
SECTION 11311
Page 15
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