(d) After moving the belt to desired pulley groove, adjust and align the belt (1, fig. 2-21).
The slurry blanket, sometimes called floc, is the jelly-like curd formed following the addition of
limestone slurry and ferric chloride solution to the raw water as the water is agitated. The jellylike floc
first appears as small particles which grow by adherence with other particles. As the water swirls, the
small particles join with others to enmesh most of the suspended bacteria, dirt, and organic mattes to
form a visible slurry blanket.
Slurry level control and sludge removal.
(a) After several hours of continuous operation, the amount of slurry in the erdlator tank will increase,
until the slurry blanket reaches the slurry drawoff port to the slurry weir box (8, fig. 2-27). The slurry flows through the
slurry weir box into the sludge concentrator tank (6). Under normal operation the plug control valves CV-16 and CV-17
(1 and 2, fig. 2-22) on the false bottom of the sludge concentrator tank will be kept open. The concentrator tank drain
valve DV-21 (3, fig. 2-16) is also kept partially open. As the slurry flows into the concentrator tank, the clear water
overflows into the inner tank and wet well. A portion of the slurry is drained to waste. The amount of slurry flow from the
erdlator to the sludge concentrator tank equals the flow through plug control valve CV-17 (2) into the wet well and the
gate drain valve DV-21 (3, fig. 2-16).
If the flow of water drawn through the plug control valve CV-17 (2, fig. 2-22) into the wet well tank (4)
or the amount of sludge drained to waste through the gate drain valve DV-21 (3, fig. 2-16) is too
great, it will cause turbulence in the sludge concentrator tank and cause slurry carryover to the wet
(b) Do not permit the slurry blanket in the sludge concentrator tank to rise above or fall below the rim
of the inner tank. Adjust the drain valve DV-21 (3, fig. 2-16) at the bottom of the sludge concentrator tank (6, fig. 2-27)
so that the amount of slurry draining to waste allows an even overflow into the inner tank.
(c) In heavy turbid water the sludge concentrator tank must be drained rapidly. Close the plug
control valve CV-16 (1, fig. 2-22) to prevent compacting heavy slurries in the circular portion and increase the opening
of the drain valve DV-21 (3, fig. 2-16) to the waste tank (7).
(d) Maintain the slurry blanket in the erdlator tank at a level to keep the slurry drawoff port in the side
of the erdlator