- It’s equally important to train kitchen staff to minimize the amount of FOG going down drains in the first place. Make sure employees:
- Scrape food waste into a trash container, not the garbage disposal. Use a rubber spatula and, if necessary, paper wipes.
- Instead of just using a hot-water spray, wipe pots, pans and work areas prior to washing, using disposable towels. (Cloth wipes will eventually be laundered, sending the grease down the drain anyway.)
- Collect waste grease and oil in containers for eventual disposal. Never pour it directly down the drain.
- Clean floor mats with soap over a utility sink (not outdoors where grease will flow into storm drains).
- Use screens or solid food separators in sink drains.
The National Restaurant Association offered many of these tips.
Types Of Grease Control Devices
Gravity Grease Interceptors (GGIs) use physics alone to slowly separate out grease and solids from the wastewater destined for the municipal sewer system—the grease floats to the top, the solids sink to the bottom, the water eventually flows through. The interceptor consists of two or more large tanks, with a volume of 300 gal. or more, usually placed outdoors. (A too-small system will push the wastewater through too quickly.) Crews must manually remove the grease layer and solids layer on an appropriate schedule to prevent clogging. Other than that, these grease-trap devices require little maintenance. GGIs are expensive, costing $15,000 to $25,000 for a new-build restaurant and $25,000 to $75,000 for a retrofit. However, unlike the more mechanically complex types of grease interceptors, they may not require health department approval for installation (though it’s a good idea to check).
Hydromechanical Grease Interceptors (HGIs) are usually what’s meant by the term “grease trap.” Standard-size HGI systems are single fiberglass or polyethylene tanks that fit under a kitchen’s three-compartment sink. HGI grease traps work using the gravity method described under GGIs, aided by interior baffles as well as vented flow control of the waste- water further up the pipes. HGIs are smaller than GGIs and thus require more frequent removal of accumulated grease and solid debris. HGIs have the advantage of being inexpensive, as little as $2,500 to $5,000 for installation and a $150 to $250 fee for each cleanout.
Large HGIs function in much the same way as under-sink HGIs, but crews install them outdoors, either above or below ground. The baffles that slow water flow are within the unit, not elsewhere in the pipe system. Although they’re larger than
the standard HGI units installed in kitchens, these HGIs installed outdoors are still smaller than GGIs and also less expensive: a belowground unit should cost $5,000 to $15,000 for new construction or $10,000 to $25,000 for a retrofit.
Automatic Grease Removal Devices (AGRDs) are indoor units connected to kitchen sinks. Like HGIs, they use gravity plus vented flow control. But they also have additional automatic grease removal components like baffles, screens and external FOG waste collector containers. Some also feature heaters, skimmers, pumps or pressure chambers. These more complex units require little space for installation, but do require additional venting. They have self-cleaning features, and well-trained employees can usually maintain them. AGRDs may cost $5,000 to $10,000 for installation or $10,000 to $15,000 for a retrofit. Each regular servicing typically costs $100 to $150.
Source: National Restaurant Association