What is FROG, and why is it a problem?
FROG stands for fats, rags, oils, and greases. Sewer overflows and backups, odor, and many other issues to the environment are a few of the reasons why FROG is a problem.
Most wastewater collection system blockages can be traced back to FROG as the cause. Blockages in the wastewater collection system are serious, causing sewage spills, manhole overflows, and sewage backups in homes and businesses.
Large amounts of FROG in the wastewater causes decreased pipe capacity in the collection system, resulting in increased maintenance costs and premature pipe replacement.
FROG also can cause treatment issues at the wastewater treatment plant. In a liquid form, it does not appear harmful. As the liquid cools and the grease congeals, it creates thick grease mats on tanks, piping, and equipment, which causes treatment problems and higher maintenance costs. In addition to fats, oils, and grease, rags and flushable wipes also cause blockages in pipes and equipment.
Frequently Asked Questions
There is a 25% standard rule for determining acceptable levels of waste that accumulate in your grease trap or interceptor. This means when the trap or interceptor has accumulated waste accounting for 25% of its wetted depth, the device needs to be cleaned.
Businesses may find that preventing FROG from entering their plumbing systems and City sewers will save money by reducing plumbing related problems.
Establishments that fail to comply with the Columbus City Utilities FROG management policy by discharging FROG to the City sewers could be required to install additional grease removal equipment or may be fined for non-compliance.
If you operate a non-residential facility that prepares and serves food, you need a grease removal system. Do not wait until you experience problems with block lines or sewer backups at your facility. You can contact the Columbus City Utilities to learn how to become compliant.
There may already be a grease trap or interceptor installed at your facility of which you are not aware. There are also some simple steps that can be done that will significantly reduce or eliminate FROG from entering your plumbing system.
YES! Facilities that prepare and serve food produce fats, oils, and grease need a grease removal device. Grease interceptors are the preferred grease removal device of the Columbus City Utilities for a number of reasons:
- They are larger, providing more retention time for the grease to congeal and separate from the wastewater.
- Some of these devices can accept discharge from dishwashing machines and food grinders.
- Grease interceptors are located outside and are less likely to create offensive odors inside the restaurant.
- They are cleaned by outside contractors every 30 to 90 days, eliminating the need to depend on staff to maintain the device.
Indoor grease traps can be effective in certain applications, but must be maintained frequently and can’t be connected to some commons kitchen fixtures and equipment. For example, grease traps cannot be connected to food grinders or dishwashing machines. Grease traps are appropriate for small, low volume restaurants with limited dishwashing and kitchen equipment.
A grease interceptor is typically a concrete vault with a minimum capacity of 750 gallons. It is connected to the restaurant plumbing and is located below the ground and outside the building. The interceptor capacity allows for enough retention time for the suspended fats, oils and grease to congeal and rise to the top. Periodically, a service contractor will pump the accumulated grease and other food waste out of the receptor to maintain its efficiency.
A grease trap is a small reservoir built into the wastewater piping, a short distance from the grease producing area. Baffles in the reservoir retain the wastewater long enough for the grease to congeal and rise to the surface. These small devices need to be cleaned often, from daily to weekly, and this is normally done by restaurant staff. Some plumbing and septic hauling companies also offer grease trap cleaning services.
Does your facility cook meat, serve soups, or salad dressing? Do you use butter, margarine, or oil in food preparation? Do you dispose of rags during food prep or clean up? Fats, rags, oils, and grease (FROG) are abundant around, in, and on the foods we eat.
When foods are prepared, oils and greases are cooked out of the food or added as ingredients or non-stick remedies. The FROG ends up on cookware, dishwater, kitchen equipment, and floors. During the cleaning of the equipment and floors, the FROG can enter the plumbing system. Shortly after this occurs, the FOG begins to cool and separate from the dishwater. After separation, the FROG will begin to accumulate in the building piping system and the public sewers. It is no coincidence that plumbers are called frequently to restaurants to unclog blocked lines.
Grease Traps and Interceptors Information
There is a 25% standard rule for determining acceptable levels of waste that accumulate in your grease trap or interceptor. This means when the trap or interceptor has accumulated waste accounting for 25% of its wetted depth, the device needs to be cleaned.
Businesses may find that preventing FROG from entering their plumbing systems and City sewers will save money by reducing plumbing related problems.
Establishments that fail to comply with the Columbus City Utilities FROG management policy by discharging FROG to the City sewers could be required to install additional grease removal equipment or may be fined for non-compliance.
If you operate a non-residential facility that prepares and serves food, you need a grease removal system. Do not wait until you experience problems with block lines or sewer backups at your facility. You can contact the Columbus City Utilities to learn how to become compliant.
There may already be a grease trap or interceptor installed at your facility of which you are not aware. There are also some simple steps that can be done that will significantly reduce or eliminate FROG from entering your plumbing system.
YES! Facilities that prepare and serve food produce fats, oils, and grease need a grease removal device. Grease interceptors are the preferred grease removal device of the Columbus City Utilities for a number of reasons:
- They are larger, providing more retention time for the grease to congeal and separate from the wastewater.
- Some of these devices can accept discharge from dishwashing machines and food grinders.
- Grease interceptors are located outside and are less likely to create offensive odors inside the restaurant.
- They are cleaned by outside contractors every 30 to 90 days, eliminating the need to depend on staff to maintain the device.
Indoor grease traps can be effective in certain applications, but must be maintained frequently and can’t be connected to some commons kitchen fixtures and equipment. For example, grease traps cannot be connected to food grinders or dishwashing machines. Grease traps are appropriate for small, low volume restaurants with limited dishwashing and kitchen equipment.
A grease interceptor is typically a concrete vault with a minimum capacity of 750 gallons. It is connected to the restaurant plumbing and is located below the ground and outside the building. The interceptor capacity allows for enough retention time for the suspended fats, oils and grease to congeal and rise to the top. Periodically, a service contractor will pump the accumulated grease and other food waste out of the receptor to maintain its efficiency.
A grease trap is a small reservoir built into the wastewater piping, a short distance from the grease producing area. Baffles in the reservoir retain the wastewater long enough for the grease to congeal and rise to the surface. These small devices need to be cleaned often, from daily to weekly, and this is normally done by restaurant staff. Some plumbing and septic hauling companies also offer grease trap cleaning services.
Best Management Practices
Keep FROG out of the Plumbing System
| Best Management Practice (BMP) | Reason | Benefits to Restaurant |
|---|---|---|
| Train all employees about how they can ensure that BMPs are being implemented. | People are more willing to support an effort if they understand the reasons for it. | All the other benefits of BMPs will have a better chance of being implemented. |
| Post "NO GREASE" signs above sinks and on dishwashers. | Signs are a constant reminder for employees working in kitchens. | These signs should help minimize grease discharge to the grease removal devices. |
| Scrape and dry wipe pots and pans prior to washing. | This will keep materials out of the grease removal devices. | This will reduce the frequency of cleaning the grease removal devices and also reduce maintenance costs. |
| Dispose of food waste in trash, not down the sink. | Greasy food solids will not contribute to the grease removal device overload or plumbing blockages. | This will reduce the frequency of cleaning the grease removal devices and also reduce maintenance costs. |
| If possible, recycle waste cooking oil. | Look for waste oil recyclers new to the Columbus area. | This will reduce cost and also reduce the amount of waste hauled to the landfill. |
Properly Maintain Grease Interceptors and Traps
| Best Management Practice (BMP) | Reason | Benefits to Restaurant |
|---|---|---|
| Supervise grease interceptor or trap cleaning and maintenance activities and document the device is operating properly. | Supervision during cleaning and maintenance activities will ensure that staff or contractors have not taken shortcuts during the cleaning process. | Restaurant will be getting the best value for the cost of the cleaning the trap or interceptor. |
| Clean under-sink grease traps weekly. If grease traps are more than 25% full when cleaned weekly, the cleaning frequency needs to be increased. | If the establishment does not have a grease interceptor, the under-sink grease trap is the only means of preventing grease from entering the sewer system. | Proper maintenance of under-sink grease out of building plumbing lines and prevents potential sewer backups. |
| Clean grease interceptors when the unit is 25% full or accumulated waste, both floatable and settleable, as measured from the tank bottom to the static water level. Grease Interceptors must be cleaned at a minimum, every 90 days. | Grease Interceptors must be cleaned routinely to prevent interceptor failure. Cleaning frequency is determined by the size of the establishment, size of the interceptor and the amount of flow delivered to the Interceptor. | Routine cleaning will prevent plugging of the sewer line, causing many problems for the establishment and the City sewer department. |
| Keep a log of grease trap and interceptor cleaning events. | The log will serve as a maintenance record of a properly serviced grease traps or interceptor, which is a requirement by the City. | The maintenance record will hep the establishment optimize their grease trap - interceptor cleaning program. |
Prohibitions Related to the Discharge of FROG
| Best Management Practice (BMP) | Reason |
|---|---|
| Do not discharge fats, oils and grease in concentrations greater than 150 ppm (mg/l) to the City sewer | Grease can solidify and trap other solid particles to completely plug the wastewater collection system. |
| Do not discharge solid or viscous waste that could cause an obstruction to the flow in the wastewater collection system. | These materials, in combination or alone, can cause blockages and other maintenance problems to the sewer system. |
| Do not discharge wastewater with a temperature of over 140 degrees into any grease traps. This includes mechanical dishwashers that have a minimum required temperature of 160 degrees. | Temperatures in excess of 140 degrees will dissolve grease, but grease can re-congeal and cause blockages further down the sewer line as the wastewater cools. |
| Do not connect food grinders to grease traps. | The food waste will greatly reduce the capacity of the grease trap for retaining grease. |