Figure 2-3. Urinal soakage pit with pipes.
(c) In addition to fire prevention, maintaining a clean field kitchen
presents additional environmental risks. Pits or reservoirs serving as a drain or
receptacle for liquids (sump holes) may be dug to dispose of kitchen water. However,
draining particles, soapy water, or chlorinated water into lakes or rivers is prohibited.
AR 40-5 and FM 21-10 specify a thorough police of the area must be accomplished.
(2) Soakage trenches. If the groundwater level or a rock formation exists
close to the surface, soakage trenches should be used instead of pits. A soakage
trench consists of a pit 2 feet square and 1 foot deep with a trench extending outward
from each of its sides for a distance of 6 or more feet (see figure 2-4). The trenches are
1 foot wide and vary in depth from 1 foot at the central pit to 18 inches at the outer ends.
The pit and trenches are filled with the same types of material as used in a soakage pit.
Two such units should be built to dispose of liquid kitchen waste for every 200 persons;
each unit being used on alternate days. The waste should first pass through a filter
grease trap. One unit should be built for each washing device provided. A soakage
trench is closed by covering it with 1 foot of compacted earth and marked in the same
manner as a soakage pit.