17.
Diatomite slurry for precoating the fiIter elements is introduced through the:
a. Precoat funnel.
b. Wet well tank.
c.
Erdlator tank.
d. Chemical slurry feeder.
18.
Under which of the following circumstances is it appropriate to recirculate fiItered
water?
a. WhiIe precoating the fiIter elements.
b. When the warning Iight and buzzer indicate a low water level in the wet well
tank.
c.
When the effluent pressure gage reading drops to about 5 psi.
d. When there is no demand for water, but it is desired to maintain the coating on
the filter elements.
e. When the flow of water from the fiIter is greatly diminished, indicating clogged
filter elements.
19.
When finished water does not have sufficient chlorine residual, the water wiII
require ____________ chlorination before it may be consumed.
20.
What initial scale reading should be set on the calcium hypochlorite feeder control
of a 1,500 gph WPU if a raw water has a chlorine demand of 5 ppm and the
required chlorine residual is 2 ppm? _____ (gal/hr).
21.
What is the chlorine demand if 1 ml of a 5,000 ppm chlorine stock solution is
added to 1,000 ml of raw water, and after a 30-minute contact period the chlorine
residual is 3 ppm? ____ ppm.
22.
What is indicated if the coagulated water has a reddish color to it?
__________________________.
MD0160
5-48