diameter. The channel shall be fabricated of steel plate of not less than
6 mm 1/4 inch thickness. The channel shall be fabricated of steel plate of
not less than 6 mm 1/4 inch thickness. The channel shall have [adjustable
weirs or stop gates, not less than three in number, spaced the full length
of the channel] [multiple discharge openings] for uniform distribution to
the aeration tank. The weir or stop gates shall be of stainless steel or
aluminum. The gates shall have 40 durometer chloroprene gaskets on the
bottom, with wedges or other means to insure a close fit. Guides for the
gates shall be of the same material as the gates. The channel shall be of
such size as to accommodate the peak flow to the plant.
2.14.7
Sludge Division Box
Sludge division box shall be provided to divide return sludge and waste
sludge when this method of sludge transfer is used, as specified in
paragraph entitled "Sludge Transfer System." The box shall be fabricated of
6 mm 1/4 inch steel plate and shall have a suitably sized connection for
incoming sludge and outlets for return sludge and waste sludge. The box
shall have a hinged plate or adjustable gate that will permit adjustment of
flow from zero to 100 percent to either outlet. Plate or gate shall have
locking nut and handle. A weir shall be provided on each outlet. Box
shall be adequately covered and/or baffled to prevent splashing of the
sludge. All joints between walls, bottom, and partitions shall be welded
continuously inside and out. After welding, all weld spatter and extreme
roughness shall be removed.
2.14.8
Settling Tank Effluent Weir and Scum Baffle
Weir and scum baffles shall be stainless steel, ASTM A 176 or ASTM A 167
steel, ASTM A 36/A 36M, or aluminum ASTM B 209M ASTM B 209 or ASTM B 221M
ASTM B 221, alloy 6061, temper T6. Weirs shall be U- or V-notched 1.57 rad
90 degreestriangular-type and of a size and section for structural
stability to handle peak flows through the plant. The upstream face of
the weir plate shall be flat and smooth. Weir plates and baffle supports
shall have slotted or oversized holes and plate washers to permit
horizontal and vertical adjustment of the weir and baffle. Weir plates
shall be mounted against a double bead of two-component
polysulfide-rubber-base sealant of sufficient thickness to fill any voids
between the concrete tank and the weir plate.
2.14.9
Mixer for Return Sludge Mixing
**************************************************************************
NOTE: Delete this paragraph and subparagraphs
thereto except for complete mixing type.
**************************************************************************
2.14.9.1
General
Mixer shall be vertical type and shall include drive assembly, impeller
shaft and impellar, and support. The mixer shall be designed to
continuously mix raw sewage with return sludge continuously so that the
mixture will be homogeneous. The mixer shall be designed for the average
design flow through the plant.
2.14.9.2
Drive Assembly
**************************************************************************
NOTE: Insert electrical power characteristics.
SECTION 11375N
Page 79
Previous Page
