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What's In a Fixture

This week I attended the Region 8 Pretreatment Association conference in Bismarck, North Dakota. The week before the conference, temperatures were in the 70’s and low 80’s (Fahrenheit for my Canadian and European friends). But just my luck, temperatures had dropped to a North Dakota friendly 45 degrees when I arrived.

Well, I wasn’t there for the weather anyway. I was there to teach two of my Grease Interceptor Training Courses: 1) The history and evolution of grease interceptors, and 2) How all grease interceptors actually work, with an emulsification demonstration. This was the first time I have attended this event and I was excited to meet so many new pretreatment professionals. Many people commented that they had never heard how we got where we are today with grease interceptors and were surprised by what they learned, in a good way. I also did an emulsification demonstration that always, and this was no exception, illuminates the minds of audience members. A lot of robust discussion surrounded both presentations.

One of the people I met was Dean Woehl, from the city of Bismarck’s pretreatment program, who took me into the kitchen of the facility where the conference was being held to illustrate one of the points I made during one of my presentations. Let’s see if you can guess what the point might have been.

Picture #1

In this picture, we have a three-compartment sink and if you look carefully you will see an Endura hydromechanical grease interceptor (HGI) on the floor under the left end of the sink. Do you see what’s neatly stacked in front of the sink? If your answer is “dishes”, you are correct. But what you may not realize is that they are all CLEAN and the sinks are empty. Where oh where did they come from?

Picture #2

Let’s look at picture #2. I turned around and took this picture of what was behind me on the other side of the room. Notice all of the dirty plates, glassware, pots, pans, etc? I wonder why they are all stacked up there? What is that fixture to the right? That’s a pre-rinse sink.

Picture #3

Notice picture #3, which helps us understand the clean-up operation. They put the dishwasher tray to the right of the sink, rinse all of the plates into the sink and then stack into the tray to run through the dishwasher.

Picture #4

Take a close look at picture #4. Would you say that they may not care what goes into that sink? Would you be surprised to find out that the sink used to have a food waste disposer (FWD) underneath it?

Where does that pre-rinse sink discharge? You saw in picture #1 where the HGI is sitting and what is connected to it. The pre-rinse sink is connected directly to sanitary. Why would that be? Would it help if I mentioned that North Dakota adopts the Uniform Plumbing Code (UPC)? Would it further help if I mentioned that section 1014.1.3 of the UPC states the following: “No food waste disposer or dishwasher shall be connected to or discharge into a grease interceptor. Commercial food waste disposers shall be permitted to discharge directly into the building’s drainage system.”

Therefore, is this a code compliant installation? Yes. Is the grease interceptor capturing the grease being produced by the facility during clean-up operations? No. Can you begin to understand why cities/utilities/pretreatment programs are FRUSTRATED with “code compliant” installations for grease interceptors?

This is why I advocate for pretreatment programs to NOT rely on plumbing codes to support pretreatment outcomes. The code is not reliable to ensure proper wastewater pretreatment has occurred at food service establishments. If you are relying on the plumbing code for your pretreatment programs’ fats, oils, and grease (FOG) control efforts, please take notice of what is actually happening in the field. If you’re not happy with what you find, it’s time to take control. I can help.

For more information about the Region 8 Pretreatment Association (R8PA), visit their website at

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