a. First Stage of FiltrationMultimedia Filter. Before raw (untreated) water reaches the multimedia
filter, polymer solution is added to it. Polymer collects suspended solids into groups large enough to be removed
by the multimedia filter. This process is called coagulation. Water is then filtered through the multimedia filter.
b. Second Stage of Filtration-Cartridge Filter. The cartridge filter takes out finer suspended solids
that pass through the multimedia filter.
c. Reverse Osmosis (R.O.) Elements. The first two stages of filtering do not remove dissolved solids
from the water. The R.O. elements, through the R.O. process, remove dissolved minerals and any suspended
solids that may have passed through the filters.
d. Chlorine Disinfection. As the water leaves the ROWPU, chlorine is added to kill any bacteria
present in the product water. At this point, the product water is stored for human consumption.
REVERSE OSMOSIS (R. O.) PROCESS. Reverse osmosis is the process by which purified water is
separated from the available seawater or brackish water source. Pressure is applied to the salt water side of a
semi permeable membrane, and purified water diffuses through the membrane to the freshwater side. The 600
GPH ROWPU is arranged so that prefiltered water is pumped under pressure across the semipermeable
membranes, called R.O. membranes. The R.O. membranes separate this water stream into a product water
stream and a brine concentrate stream, both of which continuously flow away from the membranes.
Figure 1-15. Water Processing Block Diagram