Grease Traps 101

Without a grease trap, grease and food scraps go directly into the private sewer line, which then connects to the public sanitary sewer system. Over time, grease coats the inside of these pipes and forms a clog. When a sewer line becomes clogged, it's an expensive cleanout for a restaurant and the City of Abilene!

In order for a grease trap to function properly, it must be cleaned regularly. When the grease layer inside the trap gets too thick, grease will start to leave the trap with the water since there's no more room for it to remain in the trap. When the grease leaves the trap, it coats the pipes and eventually forms a clog, which will lead to a backup or overflow of sewage. 

Hydrogen Sulfide

Likewise, if the solids are not cleaned out regularly, they will also contribute to potential problems. Food scraps and other solids will eventually begin to decompose and give off a gas called hydrogen sulfide or H2S. The H2S forms sulfuric acid when it mixes with the water. Eventually, the acid will eat a hole in the pipes or even the grease trap itself. Keeping the trap clean can prevent overflow and costly repairs.

Cool It. Can It. Trash It! applies to businesses as well as residents. One way to keep pump out frequencies to a minimum is to reduce the amount of grease and food scraps going into the trap in the first place.

• Make sure your employees are not pouring oil or grease down the drain (including floor drains).
• Scrape food scraps into the trash.
• Wipe greasy pans and dishes with a paper towel before putting them in the sink or dishwasher.
• Use a sink strainer in the drain to catch smaller bits of food.

By following good kitchen practices and maintaining your grease trap, you can avoid costly repairs and clean up from a backup or overflow.

Small grease traps are often favored because they have little upfront cost and take up less room than the large grease traps. In some situations, this may be the only option. However, many facilities are simply looking at the initial cost and don’t realize that a smaller grease trap is going to require more time and maintenance in order for it to function efficiently. Small grease traps are usually less effective than large traps for one or more of the following reasons:

• The flow control device is not present.  This device restricts the flow of water leaving the trap so that the grease has time to cool and separate. However, by restricting the flow, the drain time from the sink is also slowed down, which is inconvenient in a busy restaurant. Without a flow control device, the grease is simply flushed through the trap along with the water.
• It is not cleaned often enough. A smaller grease trap fills up faster than a larger one and will, therefore, need to be cleaned more frequently. Odor also becomes a problem since most small grease traps are located indoors.
• It is too small to remove the grease generated by the facility. While a small grease trap may work well for a small, quiet coffee shop, it may be completely overloaded by a busy greasy food place. The greasy food place would have to spend quite a bit of time and effort to keep a small grease trap working efficiently.

Because of these issues, many cities are phasing out small grease traps.