Grease Is The Word
Julius Ballanco, P.E.
If you hang around the plumbing code arena, assuming you are crazy enough to do so, the word on the street is grease. Everyone is talking about grease. If it is not grease, it is FOG, and I don’t mean the cloud that hangs close to the ground. FOG is the abbreviation for fats, oil and grease.
Within the past year, the plumbing codes have been making all sorts of changes to the grease requirements. Names have changed, sizes have changed, even the approach to capturing grease has changed. It is getting to be very confusing.
You may be asking, “What’s up?” This month I’ll try to explain these changes in simple terms.
It all starts with the federal government. The U.S. EPA established requirements for the maximum discharge of FOG many years ago. Many areas of the country have ignored the enforcement of these requirements. This, of course, doesn’t make the feds all that happy, so the feds started clamping down on the publicly owned treatment works (POTW).
The way the feds clamp down is by imposing large fines - in the millions of dollars. This sort of gets everyone’s attention.
Of course, the POTWs want to prevent any more fines, and they want to collect money to pay those fines. The POTWs start to enforce the FOG requirements, going after any building that may discharge grease. The other approach they take is to add requirements for intercepting grease.
Many POTWs have a philosophy of bigger is better. Their view of the world is to require every facility that could possibly produce grease to install a large concrete vault on the outside of the building for capturing grease. Large, as in a 500-gallon vault being considered small. Basically what you are looking at is a concrete septic tank that is designed to work as an oversized grease interceptor.
For many years, the philosophy of the plumbing codes has been to have small grease interceptors located as close to the source of the grease as possible. These interceptors are identified by flow rate or pounds of grease retained. Typically, the pounds of grease are double the flow-through rate in gpm.
These grease interceptors come in smaller sizes, such as 15 gpm (30-pound grease retention) or 25 gpm. Until recently, the size of these interceptors stopped at 50 gpm. The revised standard now includes 75- and 100-gpm sizes.
This difference in philosophy has resulted in some jurisdictions requiring a large concrete vault on the outside (by the POTW) and a smaller, localized grease interceptor inside (by the plumbing code). This, of course, is stupid. It is like requiring belts and suspenders to hold up your pants.
The manufacturers of the large vaults and normal-size grease interceptors do not necessarily get along with each other. Again, they have different philosophies for the same problem.
One of the reasons the large vaults started to make inroads is because we were not capturing all of the grease on the inside of the building. For years we thought the grease went down the three compartment sinks and the floor drains. We prohibited the drain lines from dishwashers and food waste grinders from discharging through a grease interceptor. Well, a lot of the grease escaped through the food waste grinders and the dishwashers.
The codes had to rethink their philosophy regarding dishwashers and food waste grinders. Today, those drain lines are permitted to discharge through a grease interceptor. However, they are not required to discharge through the interceptor.
Maintenance Concerns: Another problem with the smaller grease interceptors is that they were not being maintained. The big vault guys say that they can go for a long time without maintenance, because they are so huge.
To solve the maintenance problem, there has been a large influx of automatic grease removal devices or GRDs. A GRD solves the problem of maintenance by doing it automatically for the establishment. All that is required is for the grease containers to be emptied into the large grease collection barrel. The interceptor does not have to be opened up to clean out the grease.
Another line of interceptors is one that eats the grease. That, simply, is what the interceptor does. The grease is biologically remediated. You could say that bugs “eat” the grease and “belch” carbon dioxide.
The plumbing codes have been tinkering with the sizing of grease interceptors. The goal is to make sure that, whichever approach is taken, the interceptors are properly sized for the installation. The other concern is capturing all of the grease and preventing it from reaching the POTW.
If you haven’t noticed, I am a fan of point-of-use grease interceptors. The grease is captured and addressed right where it is discharged. Why risk having blocked drains from grease as it tries to make its way to a large outside vault?
I believe that the future also is GRDs and grease remediation systems. Again, why take the chance and rely on the building owner to maintain the interceptor? There are large franchises that do a good job of maintaining grease interceptors. But even these large franchises are considering GRDs and grease remediation systems. It only makes sense to simplify the life for the employees.
GRDs and grease remediation systems are a higher price, but in the long run they are cheaper to operate. They remove the grease without having to clean a grease interceptor every few days. They also assure that the grease interception process works correctly.
From your perspective, GRDs and grease remediation systems should be an easy sell to the building owner. Furthermore, the manufacturers will provide you with the documentation that proves in the long run that this is the future of grease interception.