Determining the correct size of Grease Traps

Restaurants and other food service businesses generate literally tons of cooking oil, grease and food wastes every day. If this waste is not managed properly, it can cause major environmental problems. Much of the waste is in solid form and can be safely put in packages and placed in the trash. Liquid waste containing oil and grease dumped directly into the sewer, however, can block the system and cause wastewater to flow back-up .To avoid this you have to install and properly maintain a grease trap.

Grease traps capture the oil and grease from the flow of wastewater by slowing down the flow of hot greasy water through the grease trap (actually a tank) and allowing it to cool. As it cools, the grease and oil separate out of the water and float to the top of the trap. The cooler water continues to flow down the drain pipe to the sewer while baffles prevent the accumulated grease and oil from flowing out of the grease trap. The size of the grease trap depends largely on how much waste your business produces and how often you perform trap maintenance. Grease traps may be located inside or outside of the building. Traps that are located inside the building tend to be smaller and require more frequent maintenance. Traps that are located outside the building tend to be larger and may be less disruptive to maintain. Outside grease traps will operate differently in winter versus summer and are more prone to clogging during cold weather. As a business owner/manager, you should know where the grease trap, drain lines, and clean-outs are located at your restaurant.

Proper cleaning and maintenance of the grease trap and drain line reduces the amount of solids and grease going into the public sewer system and minimizes the likelihood of back-ups or blockages. Some sanitation districts and/or municipalities require grease traps and periodic maintenance and inspections for specified businesses. This is because untrapped oil and grease in the wastewater decreases pipe capacity over time and eventually will cause the pipe to clog. Piping systems without grease traps need to be cleaned more often and some piping may have to be replaced sooner than otherwise expected. Excessive grease sent to the wastewater treatment plant can also overload their system and cause the facility to exceed its allowable discharge limits. Running extremely hot water down the drain only moves the problem down stream, and may only make it worse. Fixing a sewer line blockage can be expensive, both in terms of potentially lost customers and repair cost. If the pipe clog is within your building sewer line, you will be responsible for fixing the problem and paying all costs. If the clog is in the public sewer line, but can be traced to your restaurant, you will be liable for paying all or a portion of the repair costs. Accumulating the oil and grease close to the source in a properly maintained grease trap is the most cost-effective way.

There are several ways to maintain a grease trap and dispose of the wastes. Your decision will likely be based on cost, availability of services, and disposal/ recycling opportunities in your area. Most restaurants hire a professional pumping service to remove the waste from the grease trap and dispose of it properly. Some areas have service companies that specialize in grease trap wastes, while other areas may have pumping contractors that service grease traps, sand traps, and septic tanks. Pumping service contractors can usually be found in the yellow pages of the telephone book under the listings for “Grease Traps and Service”, “Septic Tanks”.