solution. The mixer shaft shall be plastic covered. The mixer impeller
shall be plastic. A liquid level switch shall be provided to prevent the
metering pump from operating without adequate liquid in the tank.
2.10.2
Metering Pump
The metering pump shall be a [single] [dual] head, diaphragm type metering
pump and shall have a capacity of [_____] L per day gpd of calcium
hypochlorite solution. All parts in contact with the calcium hypochlorite
solution shall be resistant to the corrosive attack of the solution. The
metering pump shall have an electric stroke length positioner to proportion
solution flow in response to a signal received from a wastewater flow
measuring device specified in paragraph FLOW METERING AND CONTROL. Control
devices shall conform to NEMA ICS 1. Motor frame shall be [_____] [totally
enclosed] [explosionproof] conforming to NEMA MG 1. The pump motor shall
be [_____] volts ac [_____] phase, 60 Hz.
2.10.3
Diffuser
A diffuser shall be provided to effectively disperse the chlorine solution
into the wastewater flow. The diffuser shall be constructed of PVC plastic
or other material resistant to the highly corrosive wet chlorine
atmosphere. The diffuser shall be installed at a point of local
turbulence, such as the outfall from a weir, to achieve rapid and thorough
mixing with the plant effluent.
2.10.4
Chlorinator Enclosure
An insulated weatherproof enclosure with a thermostatically controlled
heater shall be provided to house the chlorinator. The enclosure shall
have lockable access doors and shall be louvered for ventilation. The
enclosure shall be aluminum, galvanized steel, or mild steel with a
factory-applied finish.
2.10.5
Piping in the chlorination system shall be Schedule 80 PVC with solvent
weld joints. Gas valves shall be bronze or plastic construction. Valves
in contact with chlorine solution shall be PVC or rubber-lined steel.
2.11
SEWAGE PUMPS
Sewage pumps shall be provided for pumping [raw sewage to] [final effluent
from] the treatment plant.
2.11.1
Pumps
Duplex pumps shall be provided in compliance with Section 11310 PUMPS;
SEWAGE AND SLUDGE. Motor frame shall be [_____] [totally enclosed]
[explosionproof] type and shall conform to NEMA MG 1.
2.11.2
Controls
Pumps shall be automatically controlled by float-type level switches. The
controls shall automatically alternate the pumps upon completion of each
operation. All switches, relays, and auxiliary equipment required for pump
operation shall be provided. A magnetic starter and a combination manual
on-off control and circuit breaker shall be provided for each pump. All
controls shall be in conformance with NEMA ICS 1. All parts in contact
SECTION 11390
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