Section 2. WATER TREATMENT

inadvertent discharge under pressure from a chamber

had a rather violent reversal of water flow

in toilets on adjacent sanitary lines. This

must be prevented.

b. Storm Drain. Discharge into a storm drain may overload the lines.

The authority responsible for operating the storm sewer system should be

contacted.

Section 2.

WATER TREATMENT

1.

WATER TREATMENT. The large volume of fresh water must be treated

initially and repeatedly during the mission to reduce turbidity and control

bacteria-algae growth.

2.

TURBIDITY. When water is collected in large volumes as required in wet

pots, the actual turbidity usually exceeds the level that can be tolerated

for

the mission. Experience has shown that the only practical method of reducing

turbidity is filtration which will also remove contaminants that get into the

water when the system is in use. Filtration must be a continuing process on

the large volume of water so the filters must have very generous capacities

and be easily serviced.

It is possible to arrange the chamber system so that a low-cost low-pressure

filter will be used only when the chamber is not pressurized. However, the

limitations that this arrangement places on the chamber will usually outweigh

the one-time benefit of low initial cost. To reduce the initial cost,

filters have been installed inside the wet pot, below the floor, but they

were discarded because they were difficult and inconvenient to service. A

satisfactory filtration system, shown in Figure 7-1, has a pump, filter,

valves, and piping suitable for the operating pressures in the wet pot.

NAVFAC DM-5, Civil Engineering (Reference (1)), provides information for the

selection of filtration equipment.

3.

CHEMICAL CONTENT. Virtually all local water supplies contain chlorine

and salts of fluorine. There is no need for the designer to consider special

equipment or procedures to protect the wet pot occupants and equipment from

the effects of these chemicals. Experience has shown that by the time the

water has reached an acceptable level of clarity, the undesirable chemical

content has been reduced to an acceptable level.