a. Interceptors and Traps. Receptacles, which are preventive maintenance
interceptors and traps, in dwellings and buildings serve as waste disposal collectors for
other than ordinary household wastewater. These specially designed interceptors or
traps are frequently required for prompt removal of troublesome wastes before they
enter the wastewater collection system.
(1) Grease interceptors and traps. Removing grease from greasy wastes is
essential to proper functioning of wastewater systems. Grease is collected in two ways:
by ceramic or cast-iron grease interceptors (see Figure. 1-2) installed inside kitchens
and other facilities that generate waste grease in comparable or greater quantity, and by
concrete or brick grease traps outside the building. Inside grease interceptors are the
most common type unit and when properly maintained, they collect about 90 percent of
the grease from greasy wastes. Proper maintenance requires daily removal of all solids
and washing of all removable baffles, and a complete cleaning weekly.
Figure 1-2. A grease interceptor (or inside grease trap).