Figure 3-12. Baffle grease traps.
Filter grease trap (barrel).
(a) Construction. The filter grease trap (see Figure 3-13) may be
made from a 30- to 50-galIon barrel or drum which has had its top removed and a
number of large holes bored into the bottom. The trap is placed directly over and in the
center of the soakage pit with the bottom of the barrel about 2 inches below the surface
of the pit. As an alternative, the barrel may be placed on a platform with a trough or
pipe leading to the pit. In such a case, holes would not be made on the bottom of the
barrel. Instead, one hole would be made 3/4 of the way up the barrel on the area
closest to the pit and an outlet pipe placed in the hole. Regardless of the method, the
bottom 2/3 of the barrel would be filled with large crushed rock or gravel, followed by
smaller sized rock. Above the smaller rock, there should be 6 inches of filtering material
such as sand, charcoal, ashes, or straw. A piece of burlap or other fabric is fastened to
the top of the barrel to serve as a coarse strainer.
(b) Sanitation. Every day, the burlap is removed, then burned or
buried and replaced with a clean one. Once or twice weekly, the 6-inch layer of filtering
material is removed, buried, and replaced.