Figure 5-10. Cross-section of the erdlator assembly.
b. Ferric chloride, calcium hypochlorite, pulverized Iimestone, and (when
necessary) activated carbon are introduced directly into the mixing zone by the
chemical feeding equipment (see figure 5-7). As the raw water descends through the
mixing zone, it is mixed with the chemicals by the circular disks (see figure 5-10,
circle E) that impart a rotary motion to the Iiquid. This turbulence also helps in the
formation of floc.
c. As the water reaches the bottom of the down comer tube and flows into the
clarification zone (see figure 5-10, circle F), a series of shallow baffles (see figure 5-10,
circle G) deflect the flow and impart a counter rotary movement. The velocity is thus
reduced, but it is stiII sufficient to maintain a slight rotary movement.