fastened at each end to the tank wall near the bottom in the flow stream of
the influent to the chlorine contact tank.
2.10.9
Housing
The chlorinator scale, piping, and controls shall be enclosed in a
weatherproof housing constructed of 0.9 mm 20 gage metal with minimum 25 mm
one inch insulation. Full access door shall be provided for easy access to
equipment. The housing shall be mounted on top of treatment plant or on a
concrete pad adjacent to the chlorine contact tank which shall project not
less than 150 mm 6 inches beyond outside face of housing. A
thermostatically controlled space heater shall be provided within the
housing to maintain a temperature of 21 degrees C 70 degrees F.
2.11
PIPING
2.11.1
Piping Systems
2.11.1.1
Air Piping
Air piping shall include all piping from the blowers to the diffusers and
air lift pumps. Air supply piping from blowers to header shall be black
steel piping. Primary air header shall be black steel or black steel
rectangular section. Drop piping shall be black steel. Feeder piping
shall be black steel or aluminum. Air lift pump air supply piping shall be
black steel. Gate valves shall be provided in air piping branches from air
main when serving two or more air diffuser drop pipes; gate valves shall be
provided as blow-off valves for air mains.
2.11.1.2
Sludge Return, Waste Sludge and Scum Return Piping
Piping shall be black steel. Gate valves shall be provided on air lift
discharge piping between the air lift discharge riser and the air
separator. Gate valves, globe valves, or plug valves shall be provided in
branch piping for return sludge and waste sludge lines when separate return
sludge and waste sludge pumps are not used. A hose bibb shall be provided
in waste sludge piping.
2.11.1.3
Froth Control System Piping
Piping shall be black steel. Gate valves shall be provided in suction and
discharge piping to froth control pump and in the froth control main line
piping immediately adjacent to the hose bibb branch on the downstream side.
2.11.1.4
Miscellaneous Piping
**************************************************************************
NOTE: Delete third sentence when steel plant only
is required. On the project drawings, show:
1. Type of plant: (Extended aeration, Step
Aeration, or Complete Mixing).
2.
Design flow.
3.
5-day BOD loading.
4.
Suspended solids loading.
SECTION 11375N
Page 59
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