AUTOMATION POTENTIAL
Water flows automatically through the limestone contactors
in automated water treatment plants. Typically, the flow of
water to the contactors is the same as the plant throughput
(Spencer, 2002). The most important design parameter in a limestone
contactor is the contact time, but trying to independently control
the flow of the influent and effluent water of the contactor
is problematic. Doing so may cause a reduction in the treated
water production. Even if sufficient storage of treated water
is available, it may also complicate the monitoring process
and cause the monitoring to be costly (Stauder, 2003). Therefore,
it is important to design a limestone contactor so that it will
stabilize water at the worst conditions so that control of flow
of water to the contactor is not necessary.
Limestone contactors are cleaned periodically by backwashing
the media but backwash is generally manually initiated. Media
replacement is not automated but is done manually and is discussed
further in the operation and maintenance section.
Limestone contactor performance can be observed by monitoring
the pH. The pH can be monitored either manually or by a sensor
which feeds the data into a computer data management system.
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