c. Grease Traps. The grease trap is a necessary addition to the kitchen
soakage pit or trench. A grease trap should be of sufficient capacity so that hot, greasy
water being added will not heat the cool water already present in the trap. Otherwise,
the grease will remain uncongealed and pass through the trap instead of congealing
and rising to the top of the water. A grease trap is provided for each soakage pit and
trench, except those under showers. All kitchen liquid waste must pass through the
grease trap to remove as much grease and food particles as possible in order to
prevent the soakage pits from clogging. The Army uses two types of grease traps -- the
baffle and the filter.
(1) Baffle grease trap. A baffle grease trap (see Figure 3-12) is the most
effective way to remove grease.
(a) Construction. Before the liquid waste enters the entrance chamber
of the baffle, it passes through a strainer that removes debris or solids and grease. The
strainer is 2/3 full of loose straw, grass, or hay. The baffle is often a watertight barrel
container; however, other objects may be used. The baffle may be a box or barrel that
is divided vertically into unequal chambers by a wooden baffle. There are two
chambers -- an entrance chamber and an exit chamber. The entrance chamber is twice
as large as the exit chamber. The baffle should extend to within one inch of the bottom.
The outlet consists of a 2-inch pipe placed 3 to 6 inches below the upper edge of the
exit chamber. The container is placed on the ground along the soakage pit and the
outlet pipe is extended 1 foot beneath the surface of the ground at the center of the pit
(see Figure 3-12B). Before the baffle grease trap is used, the chambers are filled with
cool water. When the warm liquid waste strikes the cool water in the entrance chamber,
the grease rises to the surface and is prevented by the baffle from reaching the outlet to
the soakage pit. The cool water keeps the grease buoyant and causes it to float to the
top as a thick substance rather than as a thin or more Iiqidity form.
(b) Sanitation. The strainer material should be cleaned, changed, or
replaced daily. The removable strainer may be cleaned by scrubbing it with soap and
water as often as needed. Grease, sediment, and straining material should be either
burned or buried. Grease collected in the entrance chamber should be skimmed from
the surface of the water daily (or more frequently, if needed) to prevent clogging and
then burned. Once grease is removed, the trap should be drained and the sediment in
the bottom removed.