CEMP-E
EI 11C201
1 March 1997
CHAPTER 6
PUMPING STATION AND EQUIPMENT
6-1. TYPE OF CONSTRUCTION. A classification of pumping stations by capacity and the
method of construction normally utilized for that capacity is provided in Table 6-1. Factory
assembled pumping stations, commonly referred to as package type stations, are manufactured
in standard sizes and are shipped from the factory in modules with all equipment and
components mounted, installed, and ready for connection. These type stations will be suitable
for low flows, and where the need to protect pumps from clogging is minimal. Conventional field
erected pumping stations are designed for a particular location and to meet specific
requirements. Field constructed stations will be used where the quantity of flow or its variation,
or both, exceeds the capacity of available factory assembled stations, or where site conditions
require the use of special designs or construction methods.
Table 6-1. Classification of Pumping Stations.
Recommended Capacity Range
*
Class/Type
L/s(gpm)
*
*
Factory Assembled (Package Type)
*
Pneumatic Ejectors
* 2-13
(30-200)
Wet Pit Submersible Pumps
* 6-30
(100-500)
Dry Pit Pumps
* 6-125
(100-2,000)
Conventional Field Erected
*
Small
*18-95
(300-1,500)
Intermediate
*95-630
(1,500-10,000)
Large
*over 630
(over 10,000)
Note: Package type, dry pit pump stations in the capacities shown are generally available
off-the-shelf. However, station capacities up to 315 liters per second (5,000 gallons per minute)
can be obtained by special order.
6-2. PUMPS.
a. Centrifugal pumps. The centrifugal pump is the predominate type of wastewater pump
used. These pumps are available in three variations, radial flow, mixed flow, and axial flow.
Centrifugal pumps will not be used in capacities of less than 6 liters per second (100 gallons per
minute).
(1) Radial flow pumps. The radial flow centrifugal pump is the major type used for pumping
raw wastes. In a radial flow pump, the fluid enters the impeller axially and is discharged at right
angles to the shaft. Two types of radial flow pumps are available, single suction and double
suction. In a single-end suction pump, fluid enters the impeller from one side. The shaft does
not extend into the suction passage, and because of this, rags and trash do not clog the pump.
The single-end suction pump will be suitable for handling untreated wastewater. For a double
suction pump, fluid enters the impeller from both sides, however the shaft extends into the
6-1
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