GREASE TRAP TECHNOLOGY has remained virtually unchanged since the first patent was issued to Nathaniel Whiting in 1884. It wouldn’t be until many years later that standards would be adopted to regulate grease traps’ performance by the Drainage Manufacturers Association, an organization now known as the Plumbing and Drainage Institute.
Its literature includes several methods for properly sizing grease traps and clearly spells out how these devices must be sized, installed and maintained. The standards call for cleaning on a regular basis in order to have this separator of fat, oil and grease (FOG) remain effective. In most cases, that time period is one week or less!
The chances you or I will see a restaurant owner initiate a weekly or daily cleaning? When pigs fly! By the time he calls to have his grease trap cleaned, an evacuation of a 10-mile perimeter is warranted. If not, the neighbors will be calling the local coroner’s office to report the stench.
Cleaning stagnant or poorly maintained grease traps separates the men from the boys and is a rite of passage no apprentice can escape.
I can take you back to the first grease trap I was ever assigned to clean. It was in an Asian restaurant and the trap was roughly the size of a large loaf of bread. The trap was undersized, and the effluent had long since carried all FOGs through; the drains were completely clogged too. Prying off the lid revealed a cockroach condominium, and an odor escaped that was so foul it twisted my stomach in knots.
Many others have been worthy of mention. If you could package their contents with odor intact, there wouldn’t be a need for any other form of chemical warfare!
A synagogue had served a vat of uneaten onion soup to its grease trap and then called several weeks later to report an odor that couldn’t be traced to its origin. I swear the vapors were green as they wafted out of that sealed pit once I pried off the lid. The office personnel left the building within minutes as the odors found their way into the corridor, through several closed doors and into their office area.
A local mall had a parking lot grease tank of several thousand-gallon capacity designed so poorly that all the FOGs were separated and then directed to the outlet! The mall had several hundred feet of clogged drainage lines and a food court dumping copious amounts of water while the lower level stores lost thousands of dollars from merchandise damaged by the backed-up drains.
In one instance, a hunk of solidified grease temporarily blocked the tank’s outlet. The upper 5 ft. of this concrete bunker proceeded to fill until it overflowed at the manhole. Before we could respond, that chunk of grease slipped down the tank’s outlet, raced to the lower level and stopped again after it passed the bathroom connection of a toy store. The resulting grease and food particle-laden wastewater vomited from the toilet with enough force to hit the bathroom ceiling.
Naturally this was during the Christmas season when the toy store had the adjoining stock room packed floor-to-ceiling with merchandise.
Grease traps were then installed in every food court store. The mall was finally convinced that regular maintenance was required on the outdoor grease trap and the interior drainage lines. In addition, the mall added an enzyme treatment system downstream of the grease tank.
A downtown Chinese restaurant flunked its health department inspection because its 25-lb. grease trap serving a large, three-compartment scullery sink had sprung a leak at the seams. Never mind that it was below the sanitary sewer level and was being safe-wasted into an open sump pit! When I requested the sizing information the plumbing inspector would require, I gave the restaurant’s only English-speaking employee the estimate. The commotion and excited language that ensued was a sight to behold. The restaurant ended up with a sewage ejector in a sealed basin coupled to a 150-lb. grease trap. I doubt it has been cleaned since the day it was installed.
I can’t use the Plumbing and Drainage Institute or model code sizing charts in my area because each municipality has put its thumbprint on sizing requirements. The restaurant owners almost always scream bloody murder when given the pricing, and I’ve seen a number of jobs where the inspectors have backed down and allowed a reduction in capacity. Most don’t allow dishwashers to be discharged into the grease traps, even though doing so would enhance the grease trap’s performance slightly.
Perhaps it’s time all codes were beefed up to incorporate PDI sizing requirements and the use of automatic sensor-operated grease traps. After all, you and I know it’s no secret that the existing styles are virtually guaranteed to be useless from poor maintenance.
FOGs collected from automatic models are often desirable byproducts used in manufacturing. FOGs that pass through grease traps are too contaminated for reuse, increase municipal maintenance costs and create tremendous difficulties for treatment at sewage plants.
Dave Yates owns F.W. Behler, a contracting company in York, Pa. He can be reached by phone at 717/843-4920 or by e-mail at [email protected]