Grease Traps-How Cleaning and Pumping is Done by Cleaners and the Design and Installation of Big Dipper for Restaurants

Commercial Grease Trap
Stainless Commercial Grease Trap

Grease Traps-The First Line of Defense

Grease traps also known as grease interceptors are plumbing systems that serve as our first line of defense when it comes to preventing fats, oil and grease (FOG) from entering the water waste management system and eventually the ocean. A grease trap, which is usually made of hard plastic, fiberglass or concrete and placed inside the kitchen or buried underground, is therefore very important when it comes to reducing the impact of our existence to the environment. When grease from foodchains, restaurants and even from residential kitchens get into the ocean unmitigated, it would have the effect similar to an oil spill and that is why water waste management system is enacted to control this effect. But without grease traps, water waste management will have a hard time controlling the influx of FOG thus, this technology is indeed our first line of defense and without it, the price that we will have to pay will be great. If you want to check out some polyurethane grease traps check out the Schier Trapper II series.

So how does a grease trap or interceptor work? Grease traps generally work by slowing down the flow of water and grease down the drain which allows the grease to coagulate and float while the solid wastes settle down at the bottom of the trap. Through this simple separation process, the water that remains can now enter into the sewer system and into the wastewater management facility. In most cases, when the trap is small enough, it is usually installed inside the kitchen but for larger kitchens that need larger traps, it is usually installed outside the outfit.

In order for the trap to work well, it has to be maintained. Failure to maintain it will cause the FOG to enter into the sewer system and consequently you will be liable to pay huge amount of fines. Other problems include foul odor, blockages on the the drain line and back flow of water. For the sale of quality grease traps, try to check out the products of Rockford Separator Company.

Grease Trap Cleaners–The Men in Black

Grease trapAs already mentioned above, grease traps need maintenance and its a very unpleasant business. If you are not apt to the task, you can always hire the services of professional grease trap cleaners. The advantage of just hiring the pros is that they already know what they are doing and thus, they know what to expect. Added to that, they also know how to dispose of the non-hazardous materials that they have taken from your septic tank in ways that would have gotten you fined had you taken the matter in your own hands. JR Grease Services has over 30 years experience when it comes to grease trap cleaning.
When picking a grease trap cleaner make sure that you pick one that will do everything for you. This means that you get the whole package and all you need to do is pay them. I mean, do you really have to concern yourself with the ins and outs of grease trap cleaning when somebody else can do it for you? There are grease trap manufacturers or suppliers who would also offer to do maintenance, so if you are using a pre-fabricated grease trap like those from Ashland Polytrap, ask the manufacturer if they can maintain it for you.

Grease Trap Cleaning–How to Maintain a Grease Trap

According to experts, a grease trap should at least be cleaned once every three to six months. This would of course defend on its size and the traffic. If you are operating a big restaurant in the famous side of town, then you should adjust accordingly. Now hiring a grease trap cleaner might be the easiest way to maintain a trap but the caveat here is that it is also costly. This will greatly add up to the cost of maintenance overhead of your restaurant or whatever you are running.

There is a better and less costly way to maintain a grease trap and that is to use bacteria to digest the FOG. The bacteria will eat up the FOG leaving just carbon and water as byproduct. Eventually the bacteria will be washed out into the sewer system which will benefit it further because there, it will continue to eat up the FOG that escaped the grease trap. Wade International Ltd. has a grease converter which converts grease into biodegradable byproducts.

The bacteria comes in several types. There is the liquid form wherein you just pour it down the drains or directly down the trap and there is the block type where you just hang it by a rope and into the trap because it dissolves slowly and could last about four weeks. You can also install an automatic pump to your grease trap that will pump in the bacteria into the trap at set interval. This will make your grease trap virtually maintenance free.
Avoid the use of enzymes as treatment because this is prohibited in some areas and the FOG that is melted in the grease trap through this method will coagulate again in the sewer system because they are not actually eliminated.

In order to maintain a grease trap in good operating condition, you have to keep records of when procedures such as pumping out, cleaning out and adding of bacteria were done so that you will know when to do them again. Encourage your staff to throw solid waste into the trash instead of rinsing everything into the drain. If you fail to do this, expect that your grease trap will eventually be clogged out and bad odor will come out of it. Avoid hot flushing the drain, that is, pouring hot water into it because this will kill the bacteria in the trap and will prevent the grease from coagulating. If the bacteria are killed, they can no longer eat up the FOG and when grease does not coagulate, it will just flow into the sewer lines causing you to get fined as a result. For grease traps and other plumbing supplies check out Jay R. Smith Mfg. Co.

Grease Trap Pumping–Yet Another Way to Clean a Grease Trap

The other method of cleaning a grease trap is to pump out its content. This is perhaps the most common method and the costliest of all. In most cases, you would have to hire a grease trap pumping service to do it for you and perhaps you should, considering that doing it yourself is a very unpleasant business. But if you are really apt to it, here are the steps.
1. Open the cover of the trap but make sure you don’t damage the gasket. If you’ve damaged the gasket, make sure to replace it because if you don’t odor and some of its nasty contents will come out of the trap.
2. Shovel the FOG and put it in a garbage can. This will clog the pump if you will not remove it first.
3. Pump the wastewater out of the tank and make it dry. If there are some stubborn dirt, pressure wash the wall of the tank to remove it. If after pressure washing some stubborn dirt still cling to it, then it’s time to scrape it out.

4. Next, you need to put clean water into the trap. Make sure that the water level is as indicated in the specs of the grease trap.

5. Make sure that the FOG that you have removed is properly disposed or recycled.
In most areas, it is required that you keep a chart of your grease trap maintenance. This is not exactly a bad thing because this will also serve as a reminder for you. In some cases, enzymes are used to dissolve the FOG but, if you decide to use it, make sure that it is not prohibited in your area. Consult Canplas Plumbing for more information.

Grease Trap Design–The Minimum Requirements for a Grease Trap

The most common design for a grease trap is to have two chambered tank arranged in such a way that it is lined along the wastewater drain pipe. The purpose behind this design is to slow down the flow of water so the FOG will have time to coagulate. This way, the liquid as well as the solid grease and some light solid waste will be trapped while the wastewater passes below and into the sewer system. You can select a useful diagram online if you are interested. Here are the minimum requirements if you want to build a grease trap:

1. A good grease trap must slow down the passing of wastewater so that the greasy waste has time to separate out. This means that it should be able to hold all the wastewater of the kitchen at the time that it is heavily used for as long as 20 minutes ( an example of this is the Watts WD-20 grease trap which has a flow rate of 20 GPM). The capacity of your grease trap should not be smaller than 55 gallons and if there are lots of fixtures that you want to attach, you should opt for a bigger one.

2. The length of the trap should be twice its depth. You have to remember that the content of the trap usually occupies 2/3 of its total depth and the remaining 1/3 is head space. When making this measurement, the thickness of the wall should not be included.

3. The total surface area of the trap should be between 1000 to 2000 times its total depth measured in millimeters. Again wall and cover thickness should not be included in measuring this.

4. So that the wastewater and the greasy top layer will not mix, there has to be a baffle at the inlet of the trap which will slow down the flow of water coming in. The inlet pipe should be bent 90 degrees downwards so that incoming water will terminate below the trap.

5. You should provide proper access to your grease trap. This means that covers should be easy to lift up during maintenance. You should provide proper signs especially if your grease trap is an under-floor type so that people will know of its locations. You should also provide indicators for liquid depth and maximum allowable grease layer. When maintenance time comes, you should put barrier around the grease trap when it is opened.

These are just the minimum requirements of a grease trap. If you are planning to put up your own, make sure to consult the guidelines of your locality. Check the GT-500 and GT-1000 series from Oldcastle Precast which can contain 500 to 100 gallons of liquid respectively and try some of the products of Mifab as well.

Big Dipper Grease Trap–For Automatic Removal of Free-Floating (Non-emulsified) Grease and Oils

Commercial Stainless Steel Grease Trap
A picture of a new commercial stainless steel grease trap

Created by Thermaco Inc., this grease trap removes free-floating (non-emulsified) grease and oils from your kitchen drain and when properly installed, it guarantees the elimination of blockages. You see, drain blockades can be a major overhead if you are operating a foodchain because all sorts of sanitary problems will occur if they are not remedied. Before long, the government will be on your tail. Now if you have a busy kitchen, the last thing that you want would be the government writing citations and that is why you need the Big Dipper Grease Trap. Here is what sets it apart from the rest of the pre-fabricated grease traps in the market:

1. Elimination of costly sewer surcharges through the separation of water and free-floating (non-emulsified) grease and oils. If you have operated a kitchen long enough, you would be aware of the costly surcharges that you have to pay when the amount FOG that comes out in your grease trap outlet exceeds the tolerable limits. This problem will be totally eliminated because the Big Dipper grease trap is so effective in eliminating the free-floating (non-emulsified) grease and oils so that virtually nothing escapes to your outlet. The wastewater that goes to the sewer system is even pre-treated.

2. The Big Dipper eliminates cleaning and disposal costs associated with conventional grease traps because it recovers FOG on the spot. All you need to do is regularly recover the FOG deposit and dispose it properly. But wait, you don’t want to throw the FOG away because there is still something that you can do with it so read on.

3. The recovered grease and oil are suitable for recycling because it is virtually water free. This will be used as biofuel, in fact, a lot of restaurants are even gaining a steady flow of residual revenue from it. It may not be much, but you have to remember that in the past, you have to pay somebody just to collect and dispose of your FOG.

4. The performance of the Big Dipper makes it suitable for high traffic kitchens like fastfood restaurants where on the spot removal of grease is very important. Since it requires little maintenance, you can devote more time with more important things.

5. Incidental solid waste are filtered with the IS (internal strainer), adding to the low intervention and low maintenance capability. Compared to conventional grease traps wherein you would need to manually remove settle solids, Big Dipper automatically filters solids for you.

The Big Dipper Grease Trap is suitable for busy kitchens because of the features that it has. These features will greatly reduce the time spent on maintenance and repair associated with the garden variety grease traps.

Grease Trap Installation

Since having a grease trap is required by law, every restaurant, cafeteria and other catering operation should have it. When installing a unit, you have to place it at an area accessible enough for regular maintenance and large enough to house it. Here is how you can install a grease trap:

1. Determine a suitable area to install the grease trap. Remember that it should be large enough and accessible enough. In most cases, it is usually placed under the sink.

2. The next thing that you have to do after you have determined the location of the grease trap is to connect it. There are usually three connectors. The one at the upper right hand should be connected to the holding tank vent.

3. The left connection should be connected to the sink pipe. This is the pipe that comes down from the sink and loops to the straight pipe.

4. Lastly, attach the bottom opening located at the right to the sewer pipe. This will send the wastewater to the sewer system.

If you are using bacteria for your grease trap, do not pour hot water to it. This will kill the bacteria and defeat its purpose. But if you are not using bacteria, pouring hot water down the grease trap will ensure that it will work better and last longer between cleanings.

Grease Traps for Restaurants–How to Choose the Right Size

If you are running a commercial kitchen, the first thing that you have to consider is the size of the grease trap that you are going to install. You have to remember that having a grease trap is part of government regulations and there is no getting away with it. Here is how sizing grease trap is done:

1. Take the total area of the sink. In most commercial restaurants, the sink is usually composed of three basins so you have to take the total area of these basins.

2. The formula to find the area is to multiply the length, the width and height of the sink (L x W x H). If it is composed of three basins, get the area of each basin and add them up.

3. Multiply the total area with .003. The product is the amount of liquid in gallon or gallons per minute (GPM) that your sink can hold together. This is the size that your grease trap should be.

If the GPM is an odd number, it is best to round that up. There is no harm in getting a grease trap that is a bit larger than what your sink can hold. Nevertheless, do not get a grease trap that is smaller than the GPM. If you want to shop for grease traps online, check Zurn (

This is everything you need to know about how cleaning and pumping are done by cleaners and the design and installation of grease traps like Big Dipper for restaurants.


  1. Believe me, unless you are absolutely sure about what you are doing and you have the right tools and the stomach for it, it is best to hire professional grease trap cleaners. This is not a simple job and it can get very unpleasant if you make a mistake. In my opinion, cleaning a grease trap is something that is best left to someone who is experienced. You’re right too about choosing someone who will do it all – the regular maintenance and cleaning so you do not have to deal with it. While DIY is ok for minor plumbing jobs, this does not fall into that category.

  2. My question is simple. I have to
    prove a point, is the gasket on a
    grease intercepter mainly to keep
    odor contained in the trap or, to
    keep water from overflowing the
    trap. There are some techs where
    I work that seal the lid with silicone, or wax to help keep it
    from overflowing, if the exit line is
    cleaned properly and if the GPM is
    a match to the tank in use, then it
    should’nt overflow correct?

    1. The gasket is to seal the trap from emitting odors and gasses not to keep water from leaking out of the trap. If you have a properly sized trap and you maintain that properly sized trap you should never have an issue. Your point is proven correct.


      1. I have an Ashland 4820 and the gaskets on the lid and baffles have dissolved basically and I am wondering how would a person put new gaskets/silicone on and expect it to stick. Is the gasket central to the effectiveness?

        1. OK first of all thanks for asking the question. It’s because of you that the site works. Now to you your question. Ashland grease traps. The gasket fits in the slot on the backside of the lid so you shouldn’t need any adhesive to make it stay put. Yes it is essential to it’s effectiveness as it blocks offensive odors from leaving the trap. Which can be pretty offensive if you want my .02. I have contacted Ashland and they will send you a new gasket. Here is their number 419-836-2300 or 800-541-8004 and ask for David or Paul. They will take care of you.


  3. We installed Big Dipper 4000 automatic in November 2015. In September 2016, less that in a year, it stopped skimming. Termico suppose to give one year warranty, but it’s one year since the unit left their factory. And in my case, for about 6 month it set in the warehouse. So, we did not get warranty service. Now the problem even worst – water coming out from the inlet! So, we can’t use the sinks. It’s a nightmare.
    A manual said that it needs to be cleaned ones in 3 months – actually, if it not cleaned ones a week, all problem starting. $3000 for a metal box, a strainer, plastic P-Trap and a small electric motor that works less than a year. It’s a worst price of equipment I ever had. Beware – Termico!

    1. First of all it’s Thermaco. If we’re gonna complain lets complain right. Let me preface this by saying Thermaco is a very reputable automatic grease trap manufacturer. How did you buy this product? On-line, from a local plumbing supply company, a contractor? Most manufacturers give you a one year warranty from date of manufacture however when a distributor buys it and stocks it they usually give you a one year as well. So will a contractor, in fact in cases such as yours I would give a 24 month and just build it into the cost of the project. Find your local Thermaco rep and let them know about the problem.

      Sean K

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