What is a Grease Trap?
A grease trap or grease interceptor is a receptacle located between the restaurant drain lines and the sanitary sewer lines that allows for the separation and collection of fats, oils and greases (FOG) from the used water, preventing such materials from entering the municipal sewer system.
The grease trap can either be located inside of the establishment or on the outside. Typically large restaurants or school kitchens will have their grease trap/ grease interceptor located outside of the facility, usually in the ground, while facilities with smaller traps can usually house theirs indoors.
How does a grease trap work?
Grease traps slow down the flow of water coming from drains, allowing the water/ grease time to cool. This cooling causes the grease to coagulate and float to the top, while other, heavier solids, fall to the bottom of the trap. The remaining water is free to pass through on to the city sewer lines
A grease trap works with hydraulic pressure and gravity. When you empty your three compartment sink, the water flows into the grease trap.
It then hits a baffle which slows down the water. This allows the solids to sink to the bottom of the trap and the fats and oils to float to the top.
The water pressure from the incoming side then pushes the water that has had time to settle out of the trap and into the sanitary sewer line or the septic system.
The Do's:
Schedule regular grease cleanings.
Make sure that food prep and wash sinks are tied into a trap.
Ensure that your trap is properly sized.
Train your staff to remove as much waste and food solids as possible from plates and pots before washing.
Maintain a cleaning log for code compliance.
The Don'ts
Don't pour boiling water into a trap connected sink as it forces FOG's down the sewer pipe.
Don't connect garbage disposals to a trap.
Don't connect high temperature dishwashers to a trap.
Don't put chemicals, bleach, additives, or drain cleaners into a trap - they destroy naturally beneficial bacteria and risk harm to the environment