Grease interceptors take in the flow of water from the parts of your restaurant that produces grease, and filters it out, before the waste water passes into the city’s drains. Since a large flow of water – such as ones from many kitchen and production sinks that could potentially be turned on all at once – could compromise a smaller grease trap, the largest factor on the right size for a restaurant’s interceptor is the volume flowing through it, and not the actual contents of flow. While this works (the flow will never overwhelm the unit when clean), depending on the amount of grease the restaurant produces that makes it into the interceptor can become overfull with grease, which also compromises the trap and requires additional cleaning.
Calculating the Grease
This handy chart made by Ken Loucks (aka the Interceptor Whisperer), breaks down the amount of grease a restaurant (in general) produces.
Following the chart above, you can calculate the amount of grease a restaurant produces. This, together with the flow, allows you to figure out the base size the trap needs to be, and how much larger the capacity of the interceptor needs to be to be services within a certain time frame (such as every month, every two month, etc).
Type of Grease Trap
Much like the layout and volume of a restaurant kitchen can vary wildly, so to can the type of grease trap. These vary from small units mounted underneath the sink and serviced daily, to medium units hiding out with the utilities, to massive in-ground units. The name (grease trap or grease interceptor) tends to be technical in nature, but is interchangeable in regular conversation. When you’re deciding on the size and type of your trap, it’s important not to only think about the grease produced by washing kitchen tools or customer dishes and flatware, but also:
- Mop water is going to be filled with grease. Do you need a separate drain for it?
- Barista sinks see a lot of milkfat, is that hooked into the interceptor?
- Floor drains around your wash sinks and deep fryer are grease magnets, are they hooked in?
When you’re thinking about the size and type of trap, it’s important not to think about only the volume, but where it’s coming from. Not only could an unconnected source cause buildup (which can haunt you with backwash or unhappy city ordinance officers), but it might be more that you planned for. Nothing ruins your day like a grease trap seized solid with grease.
Grease Trap Servicing
As a grease trap servicing company, we’re a little biased when it comes to regularly servicing your grease traps, we’ll admit it. However, we know the horrors of a grease trap that is days, weeks, or even months over service (we’ve got the photos to prove it, though you may not want to look at them). Remember, these grease traps are required by law, and if they aren’t working, that’s a problem.
Ideally traps should be emptied when a quarter of the total liquid volume is filled with solids or oil. This is known as the rule of 25%. After this point, more and more grease is going to flow into the interceptor… and right out again. It’s important to set up a regular servicing schedule, and if you’ve got a small unit you’re emptying (or supposed to) each day, maybe it’s time to upgrade to a larger trap and a monthly service cycle. Whatever your situation, give Food Grease Trappers a call: we do servicing of all types of traps and interceptors, and have 20 years of experience to deal with your unique needs.
