First Stage of Filtration-Multimedia 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.
Second Stage of Filtration-Cartridge Filter. The cartridge filter takes out finer suspended solids that pass
through the multimedia filter.
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.
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 semipermeable
membrane, and purified water diffuses through the membrane to the freshwater side. The 600 GPH ROWPU is arranged
so that pre-filtered water is pumped under pressure across the semi-permeable 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