A commercial grease trap is a separation chamber that slows kitchen wastewater so fats, oils, grease and food solids can be retained before the water reaches the drainage system.
What happens inside a commercial grease trap?
Wastewater from pot-washing, sinks and food preparation enters the unit. Its flow is slowed inside the trap, allowing lighter grease to rise and heavier particles to settle. Water leaves through the outlet from the clearer middle layer.
Internal baffles and chambers vary by model, but the principle is the same: the trap needs enough time and free capacity for separation to take place.
Why grease and food solids stay behind
Retained material does not disappear between visits. Grease can build at the surface, solids can collect at the bottom and residue can remain on accessible internal surfaces. Over time that reduces the volume available for the trap to do its job.
How quickly this happens depends on the kitchen. A busy takeaway, restaurant or production kitchen can load a unit very differently from a quieter site, even where the traps appear similar.
What changes when a trap reaches capacity?
As retained waste occupies more of the chamber, there is less space for the incoming flow to slow and separate. This is when kitchens can begin to notice drainage problems, odours or a trap that needs attention sooner than expected.
A grease trap helps manage what enters the drainage system; it does not make the retained material vanish. Timely service restores working capacity before the system is allowed to become heavily loaded.
Internal and external traps need different planning
Smaller units may sit beneath a sink or within the kitchen, while larger interceptors are often outside beside a service yard or access route. The location changes how a contractor reaches the unit, how equipment is positioned and what information is useful before a visit.
For example, an internal or basement installation may need more advance planning than a readily accessible external interceptor. Sharing access details early helps the right service be arranged.
Emptying, cleaning and maintenance are related but different
Grease trap emptying removes the retained contents and restores capacity. Grease trap cleaning can go further where accessible residue needs attention. Planned maintenance uses the condition found at each visit to help keep the interval suitable for the site.
There is no useful one-size-fits-all interval. Service history, kitchen output and the condition of the trap provide a better basis for deciding what the next visit should involve.
It can only separate effectively while there is enough working capacity inside the unit.