How Your Grease Trap or Grease Interceptor System Works
Grease traps and interceptors are regarded as plumbing fixtures, and are required by any business or establishment serving food and drink, in compliance with the Grease Ordinance (regulated by your local EPA).
Grease traps and interceptors are essentially reservoirs that trap greases, oils, fats and food solids from dish wash water, preventing them from draining into the sewer or septic systems and causing blockages. At the intake end there is a flow control valve, and an air intake valve to counteract siphonage and back-pressure issues. The reservoir is divided into two compartments by a baffle, an internal containment wall that extends from the top until just above the bottom of the reservoir.
At the outtake end, there may be a sample point to allow for the checking the effluent, and a cleanout point to allow for the removal of any blockages from the outlet pipe. An air relief pipe maintains air circulation within the trap or interceptor.
Grease traps are installed indoors, above the ground and are usually made from plastic, PVC, fibreglass or steel and required, by law. Grease interceptors are larger and installed outside and in the ground. They are usually made from cement, PVC or fibreglass.
As fats, oils and grease are less dense than water, they naturally float to the top of the first compartment, and the baffle serves to retain the FOG as the waste water drains into the second compartment which leads to the outflow pipe. The denser food solids sink to the bottom of the trap or interceptor. As the waste water cools and drains off, it is displaced by the FOG which slowly hardens, forming a layer over the food solid sludge that remains on the bottom of the tank.
As you can imagine the amount of FOG and food solids trapped builds up daily and need to be cleaned regularly to continue working effectively. Regulations dictate they need to be emptied or pumped out when the trapped FOG and solid waste are at 25 percent volume. As these levels are difficult for a lay person to measure, it is advisable to call in a professional service provider that specializes in cleaning grease traps and interceptors.[A grease trap or interceptor cleaning company will have a truck equipped with a tank into which the FOG and solid waste is pumped, and so removed. When choosing a service provider, make sure they are reputable and licensed, and be sure to check the trap or interceptor post pumping to ensure the job has been completed properly.] [From time to time the flow control valve and/or baffle also need to be cleaned or repaired. It’s important to keep these in good working order otherwise the water flows too quickly forcing the FOG and solid waste into the outlet pipe.]
Another important factor to consider when installing a grease trap or interceptor system is size. Yes, in this case size counts, as you need to be certain the system you choose is able to handle the volume of dish wash water from the various sinks and automatic dishwasher in your restaurant or food facility. Again it is advised you consult a professional who can help you calculate the size of trap or interceptor required.
Putting a routine maintenance schedule in place can save you in the long term and prevent the stress and extra costs that comes with an emergency call out situation. So save your establishment an embarrassing fine or citation; the potential damage to your restaurant or food facility’s reputation is simply not worth it.