Figure 7 shows a portable pit privy suitable for places of the character
of that shown in figure 1, where land is abundant and cheap, and in such
localities has proved practical. It provides, at minimum cost and with
least attention, a fixed place for depositing excretions where the filth
can not be tracked by man, spread by animals, reached by flies, nor washed
by rain.
[Illustration: Fig. 7.--Portable pit privy. For use where land is abundant
and cheap, but unless handled with judgment can not be regarded as
safe. The privy is mounted on runners for convenience in moving to new
locations.]
The privy is light and inexpensive and is placed over a pit in the ground.
When the pit becomes one-half or two-thirds full the privy is drawn or
carried to a new location. The pit should be shallow, preferably not over
2-1/2 feet in depth, and never should be located in wet ground or rock
formation or where the surface or the strata slope toward a well, spring,
or other source of domestic water supply. Besides standing on lower ground
the pit should never be within 200 feet of a well or spring. Since dryness
in the pit is essential, the ground should be raised slightly and 10 or
12 inches of earth should be banked and compacted against all sides to
shed rain water. The banking also serves to exclude flies. If the soil is
sandy or gravelly, the pit should be lined with boards or pales to prevent
caving. The privy should be boarded closely and should be provided with
screened openings for ventilation and light. The screens may consist of
standard galvanized or black enameled wire cloth having 14 squares to the
inch. The whole seat should be easily removable for cleaning. A little
loose absorbent soil should be added daily to the accumulation in the pit,
and when a pit is abandoned it should be filled immediately with dry earth
mounded to shed water.
A pit privy for use in field work, consisting of a framework of 1/2-inch
iron pipe for corner posts connected at the top with 1/4-inch iron rods
bent at the ends to right angles and hung with curtains of unbleached
muslin, is described in Public Health Report of the United States Public
Health Service, July 26, 1918.
A pit privy, even if moved often, can not be regarded as safe. The danger
is that accumulations of waste may overtax the purifying capacity of the
soil and the leachings reach wells or springs. Sloping ground is not a
guaranty of safety; the great safeguard lies in locating the privy a long
distance from the water supply and as far below it as possible.