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Water Treatment
Water Treatment > Quality
Water Solutions > Coagulation Control
> Pilot Filters
Pilot filters inform operators about the quality of the
water emerging from the plant's full-scale filters by defining how a coagulant
program affects filtered water turbidity. They are placed on-line just after
coagulation, if the source water is relatively clean, or after clarification, if
the water has a heavy load of contaminants. Pilot filters see the same water as
the rest of the plant and give early warning of coagulant demand shifts.
A pilot filter may replicate full-size filters or may
simply be a small column of anthracite or other filter media. The turbidity of
its effluent can be monitored periodically or continuously. These readings guide
operators in changing coagulant based on past experience.
Filter backwashing in full-size filter simulations is often based on headloss
or turbidity breakthrough. Smaller pilot filters usually backwash automatically
with a timer or in response to turbidity breakthrough. They are relatively inexpensive
to build, operate, and maintain.
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