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Frequently Asked Questions on Fats, Oil and Grease

1. Why is my oil and grease discharge high?

There are generally three reasons for high oil and grease levels discharged from food preparation facilities. First, kitchen personnel may be disposing of used oil down the drain. This is rarely the case, however. Second, some older buildings do not have grease interceptors, or outside grease traps, to capture grease normally generated from kitchen activities. Third, poor maintenance, or no maintenance at all, of grease retention devices is the major contributor to oil and grease problems


2. What can I do to lower the levels of oil and grease being discharged to the public sanitary sewer?

Oil and grease levels can be lowered in several ways. First, your employees should be carefully instructed in the procedures to properly dispose of oil and grease. As an example, oil from deep fryers should be put in a rendering barrel. Second, you should consider the installation of an outside grease trap of adequate size and proper design to capture the oil and grease from your wash water. Inside grease interceptors are generally not as effective as an outside grease trap because they do not provide sufficient detention time for the water to cool and release the grease. This is particularly true where automatic dishwashers are used.Third, and probably most important, proper maintenance of inside grease interceptors and outside grease traps can lower the oil and grease levels discharged to the public sanitary sewer. Grease interceptors should be cleaned out in accordance with the manufacturer’s recommendations, generally once a week, depending on the size of the interceptor and the volume of water discharged through it. Outside grease traps should be cleaned out about once every month or two. Greater the grease accumulation, in either device, greater is the frequency of maintenance. Grease traps and interceptors sometimes, unfortunately, are not maintained for years, or until they begin to back up into buildings.

Should you have further questions pertaining to oil and grease problems, contact the Water Quality Compliance Supervisor at telephone number (804) 501-7609.

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