Researchers estimate that U.S. restaurants alone produce about 25 billion gallons of used cooking oil every week. Residential customers also add to this total. Much of these fats, oil and grease (FOG) end up in sewer systems causing expensive blockages and backups, as well as overflows that damage the environment. It also creates problems at the wastewater treatment facility which increase operational budgets, only to pass the extra cost to the consumer. With proper grease management, YOU can minimize pollution and your expenses.
FOG is a by-product that food service establishments and residents must constantly manage. In general, FOG enters a facility's plumbing system from dish washing, floor cleaning and equipment sanitation. Sanitary sewer systems are not designed nor equipped to handle the FOG that accumulates on the interior of the municipal sewer collection system pipes. Sanitary Sewer Overflows (SSOs) are the result of pipe blockages from FOG accumulation from residential, institutional and commercial sources. The best way to manage FOG is to keep the material out of the plumbing systems. The following are suggestions for commercial and residential customers to properly manage FOG.
Residential Do's and Don'ts when disposing FOG...
- Recycle used cooking oil or properly dispose of it by pouring it into a sealable container and placing the sealed container in the trash. If you have a lot of oil to dispose of, use cat litter. Just mix the litter, a little at a time, into the oil. When all the oil has been absorbed, pour the cat litter into a trash bag, seal the bag and then dispose of it in your regular trash.
- Scrape food scraps into the trash, not the sink
- Wipe pots, pans and dishes with dry paper towels before rinsing or washing them, and then throw away the paper towels.
- Place a catch basket or screen over the sink drain when rinsing dishware, or when peeling or trimming food to catch small scraps that would otherwise be washed down the drain. Throw the scraps in the trash.
- Rinse dishes and pans with cold water before putting them in the dishwasher. Hot water melts the FOG off the dishes and into the sewer pipes. Later on in the sewer, the hot water will cool and the FOG will clog the pipes.
- Don't use a garbage disposal or food grinder. Grinding food up before rinsing it down the drain does not remove FOG; it just makes the pieces smaller. Even non-greasy food scraps can plug your home's sewer lines. So, don't put food of any kind down the drain.
- Don't pour cooking oil, pan drippings, bacon grease, salad dressings or sauces down the sink or toilet or into street gutters or storm drains.
- Don't use cloth towels or rags to scrape plates or clean greasy or oily dishware. When you wash them, the grease will end up in the sewer.
- Don't run water over dishes, pans, fryers and griddles to wash oil and grease down the drain.
Commercial Disposal of FOG
Practice dry cleanup. Remove food waste with "dry" methods such as scraping, wiping or sweeping before using "wet" methods that use water. Wet methods typically wash the water and waste materials into the drains where it eventually collects on the interior walls of the drainage pipes. Do not pour grease, fats or oils from cooking down the drain and do not use the sinks to dispose of food scraps. Likewise it is important to educate kitchen staff not to remove drain screens as this may allow paper or plastic cups, straws and other utensils to enter the plumbing system during clean up. The success of dry clean up is dependent upon the behavior of employees and the availability of the tools for removal of food waste before washing. To practice dry clean up:
- Use rubber scrapers to remove fats, oils and grease from cookware, utensils, chafing dishes and serving ware.
- Use food grade paper to soak up oil and grease under fryer baskets.
- Use paper towels to wipe down work areas. Cloth towels will accumulate grease that will eventually end up in your drains from towel washing/rinsing.
Preventing spills reduces the amounts of waste in food preparation and serving areas that will require clean up. A dry workplace is safer for employees and can help prevent slips, trips and falls. For spill prevention:
- Empty containers before they are full to avoid spills
- Use a cover to transport interceptor contents to rendering barrel.
- Provide employees with the proper tools to transport materials without spilling.
Minimize Production of FOG
- Prevent oil spills - Remind kitchen workers to be careful when handling oil and fats.
- Bake food instead of frying - Baked foods are healthier and produce less oil waste. Baking is also more energy-efficient than frying. With a convection oven, baked foods can acquire the crispiness of fried foods.
- Reuse clean oil - Do not throw out oil from skillets, pans and/or woks if it is still clear and can be used for cooking.
Maintenance is key to avoiding FOG blockages. Whatever method or technology is used to collect, filter and store FOG ensure that equipment is maintained regularly. All staff should be aware of and properly trained to perform correct cleaning procedures, particularly for under-sink interceptors that are prone to break down due to improper maintenance. A daily and weekly maintenance schedule is highly recommended.
- Contract with a management company to professionally clean large hood filters.
- Small hoods can be hand-cleaned with spray detergents and wiped down with cloths for cleaning.
- Hood filters can be effectively cleaned by routinely spraying with hot water with little or no detergents over the mop sink that should be connected to a grease trap. After a hot water rinse (separately trapped), filter panels can go into the dishwasher.
- For hoods to operate properly in the removal of grease-laden vapors, the ventilation system will also need to be balanced with sufficient make-up air.
- Make sure all drain screens are installed.
- Prior to washing and rinsing use a hot water ONLY (no detergent) pre-rinse that is separately trapped to remove non-emulsified oils and greases from dish washing. Wash and rinse steps should also be trapped.
- Empty grill top scrap baskets or scrap boxes and hoods into the rendering barrel.
- Easy does it! Instruct staff to be conservative about their use of fats, oils and grease in food preparation and serving.
- Ensure that edible food is not flushed down your drains. Edible food waste may be donated to a local food bank. Food donation is a WIN-WIN situation. It helps restaurants reduce disposal costs and it puts the food in the hands of those who can use it.
For grease traps to be effective, the units must be properly sized, constructed and installed in a location to provide an adequate retention time for settling and accumulation of the FOG. If the units are too close to the FOG discharge and do not have enough volume to allow the build -up of FOG, the emulsified oils will pass through the unit without being captured. For information on properly locating, constructing and sizing grease traps, contact your local county and city representatives.
- Ensure all grease-bearing drains discharge to the grease trap. These include mop sinks, woks, wash sinks, prep sinks, utility sinks, dishwashers, pre-rinse sinks, can washes and floor drains in food preparation areas such as those near a fryer or tilt/steam kettle.
- No toilet wastes should be plumbed to the grease trap.
- If these suggested best management practices do not adequately reduce FOG levels, the operator may consider installing a second grease trap with flow-through venting. This system should help reduce grease effluent substantially.