Environmental Engineering Reference
In-Depth Information
Table 2.2 PuMP aPPliCaTions
in WaTer/WasTeWaTer sysTeMs
application
function
Pump Type
Low service
To lift water from the source to treatment
processes or from storage to the filter-
backwashing system
Centrifugal
High service
To discharge water under pressure to the
distribution system; to pump collected or
intercepted wastewater to the treatment
facility
Centrifugal
Booster
To increase pressure in the distribution/
collection system or to supply elevated
storage tanks
Centrifugal
Well
To lift water from shallow or deep wells and
discharge it to the treatment plant, storage
facility, or distribution system
Centrifugal
or jet
Chemical feed
To add chemical solutions at the desired
dosages for treatment processes
Positive-
displacement
Sampling
To pump water/wastewater from sampling
points to the laboratory or automatic
analyzers
Positive-
displacement
or centrifugal
Sludge/
biosolids
To pump sludge or biosolids from
sedimentation facilities to further treatment
or disposal
Positive-
displacement
or centrifugal
Source:
Adapted from AWWA,
Water Transmission and distribution
, 2nd ed.,
American Water Works Association, Denver, CO, 1996, p. 358.
To understand pump operation, or pumping hydraulics, we need to
be familiar with certain basic terms and then relate these terms to how
water is pumped from one point to another (see Figure 2.13):
Static head
—The distance between the suction and discharge water
levels when the pump is shut off. Static head conditions are repre-
sented by the letter
z
(see Figure 2.13).
Suction lift
—The distance between the suction water level and the
center of the pump impeller. This term is used only when the pump
is in a suction lift condition; the pump must have the energy to
provide this lift. A pump is said to be in a suction lift condition
any time the center (eye) of the impeller is above the water being
pumped (see Figure 2.13).
Suction head
—A pump is said to be in a suction head condition any
time the center (eye) of the impeller is below the water level being
pumped. Specifically, suction head is the distance between the suc-
tion water level and the center of the pump impeller when the pump
is in a suction head condition (see Figure 2.13).
Total dynamic head
—The total energy needed to move water from the
centerline of a pump (eye of the first impeller of a lineshaft turbine)
to some given elevation or to develop some given pressure. This
includes the static head, velocity head, and the head loss due to
friction (see Figure 2.13).
