Fats, Oils and Grease (FOG) cause problems with sewer systems, including the City of Columbia’s. When food particles, cleaning products and FOG flow to a sewer system, they can cause clogs that lead to sanitary sewer overflows, which can create environmental and public health concerns.

Columbia Water’s Commercial FOG Management Program enforces standards set under the City’s Sewer Use Ordinance for FOG-related discharges into the City’s sanitary sewers. Detailed requirements can be found in the City’s Engineering Regulations Part 29 and Part 30.

Any business that regularly prepares food, whether for on-site consumption like restaurants and schools, or for late consumption, like grocery stores, has the potential to add FOG to our sewer system. Under Sewer Use Ordinance Sec. 23-114, these businesses need to make sure they have proper structures and procedures in place to prevent FOG from entering our sewers.

Food Service Establishments may want to consider using a responsible grease renderer to turn nuisance FOG into a usable, recycled product. Renderer’s service fees are often low, and in some cases, they may be willing to pay for restaurant oil and grease.

Structures and Procedures

Grease Traps

About Grease Traps

A grease trap is typically small and located under or near a sink. it should be cleaned regularly based on your establishment’s needs. Cleaning the trap is a simple procedure that can take little time. Traps can be cleaned by in-house staff or by a licensed grease hauler or recycler. The interval between cleaning depends on the individual establishment. A good rule of thumb is to clean the trap weekly. If the trap is more than 50% full of solids when cleaned weekly, increase the frequency of cleaning. Management should witness or inspect the cleaning to ensure it is done properly.

Cleaning Grease Traps

Always follow the cleaning requirements outlined in Part 29: Section 29.3.5. Generally, this includes:

  • Stopping all flow to the trap
  • Removing the trap cover
  • Scooping out any FOGS on the top
  • Bailing out any water in the trap
  • Removing baffles
  • Scraping the sides, lid and baffles. Putting FOG into a FOG waste container.
  • Recording the volume of FOG removed and date on the Maintenance Log For Cleaning XLS document. Keep this log on-site for 2 years. Keep the maintenance log up to date and readily accessible. This serves as a record of the cleaning frequency and can help the establishment manager optimize cleaning frequency to reduce costs.

Grease Interceptors

About Grease Interceptors

A grease interceptor is much larger than a grease trap and is usually located outside. The minimum size is 1,000 gallons.

It should be cleaned regularly (at least every six months) by a licensed grease hauler or recycler. The actual schedule should be based on your establishment’s needs and can range from weekly to every six months.

Cleaning the interceptor vaults requires special training and equipment. It is very important that a restaurant representative be present during any cleaning, pumping, or skimming performed by a contractor to ensure that no shortcuts are taken. They should always follow the cleaning requirements outlined in Part 29: Section 29.3.6 .

Servicing Grease Interceptors

The minimum services should include:

  • Complete pumping and cleaning of the interceptor and sample box (not just skimming the grease layer)
  • Deodorizing and thorough cleaning of affected areas, as necessary
  • Reclaiming FOG or disposing of it at an approved location
  • Refilling the vault with clean water (not water already pumped out)
  • Record the volume of grease removed on a Maintenance Log For Cleaning

The cleaning frequency depends on the individual establishment. Interceptors require cleaning at least every six months. However, frequency depends on the capacity of the device, the amount of grease in the wastewater, and the degree to which the facility has contributed to blockages in the past. Thus, the frequency can range from weekly to every six months.

Regulations and Ordinances

Regulations and Inspection

The City of Columbia has a FOG program to address and prevent FOG from entering the sewer system. Standards and limitations on materials that may be discharged into the City’s sanitary sewers are established in the City Code of Ordinances, Chapter 23, Article IV, Sections 23-101 through 23-115. This helps protect the equipment in the treatment process and is required by the United States Environmental Protection Agency. You can also call +1 (803) 545-3400 to request this information by mail.

Frequently Asked Questions

What is FOG?

FOG stands for Fats, Oils and Grease. FOG includes cooking oil, butter, margarine, bacon grease, dairy cream, and other fats typically used in cooking. They can be liquid or solid.

What is the Commercial FOG Program?

Columbia Water has a Commercial FOG Program. The program requires Food Service Establishments (FSEs) discharging into the City’s sewer system to use properly sized grease traps or interceptors to limit the levels of FOG in their sewer discharge.

Why does Columbia Water have a FOG program? How does Columbia Water benefit?

The Commercial FOG Program helps protect the City’s sewer system and equipment in the wastewater treatment process. This program is also required by the United States Environmental Protection Agency (40 CFR 403).

FOG that enters the City’s sewer system can clog gravity sewer lines and air release valves. These clogs can cause pump station failures that lead to Sanitary Sewer Overflows (SSOs). By reducing the levels of FOG discharged into our sewer lines, FSE’s can aid in preventing clogged sewer lines and equipment failures, ultimately reducing the number of SSOs.

How do sewer customers benefit from a FOG program?

Limiting the amount of FOG levels entering the City’s sewer system helps reduce costs related to maintaining the sewer system. The City spends a significant amount of money and man-hours unclogging and cleaning waste water collection lines. Because these costs are passed on to City customers through our sewer rates, the less the City has to spend on FOG related-issues, the less these costs are passed on to the customer.

Where does Columbia Water get its authority to limit what goes into Sanitary Sewers?

Standards and limitations on materials that may be discharged into the City’s sanitary sewers are established in the City Code of Ordinances, Chapter 23, Article IV, Sections 23-101 through 23-115.

How long has Columbia Water had a FOG program?

The City has done periodic inspections of grease traps for many years under the authority granted in the City Code of Ordinances, Chapter 23, Article IV, Sections 23-101 through 23-115. In 2009, these periodic inspections were expanded into the Commercial FOG Program. The first full-time FOG inspector was hired and began inspecting in the spring of 2009.

Has there been any improvement in the number of sanitary sewer overflows caused by grease?

line graph showing the reduction in sanitary sewer overflows from 2010 to the presentYes. Through the commercial FOG program and the residential Trash the Grease campaign, Columbia Water has seen a drastic reduction in sewer overflows. In FY17-18 there were only three sanitary sewer overflows directly related to grease clogs.

Who is affected by the FOG program?

Any food service establishment that regularly prepares food, whether for on-site consumption like restaurants and schools, or for late consumption, like grocery stores, has the potential to add FOG to our sewer system. Under Sewer Use Ordinance Sec. 23-114, these businesses need to have proper structures and procedures in place to prevent FOG from entering our sewers.

Doesn't DHEC already inspect grease traps for the food service industry? Why does Columbia Water also inspect grease traps?

SC Department of Health and Environmental Control (DHEC) and Columbia Water both inspect grease traps for different reasons. Columbia Water inspects grease traps to determine if they are functioning and/or being used properly to reduce the levels of FOG entering the sewer system and to ensure maintenance is being performed. This inspection does not cover food handling practices. Food handling inspections fall under the jurisdiction of SCDHEC.

What is required of regulated businesses?

Under Sewer Use Ordinance Sec. 23-114, food service establishments (FSE) need to have proper structures and procedures in place to prevent FOG from entering our sewers.

Structure Sizing: The sizing requirements are based on the type of FSE and the amount of food prepared in addition to the degree of customer traffic. FSEs can use the Grease Trap Sizing Guide to determine how large the structure should be. The structure should be sized to prevent any water or waste containing more than 100 mg/L of FOG from entering the City’s system.

Maintenance: FSEs need to develop proper operation and maintenance procedures for maintaining their grease traps and grease interceptors.

What do FOG inspectors look for?

Inspectors will need to look inside the grease trap or interceptor. They will inspect the level of grease in the structure and determine if proper maintenance is being performed. They will also look at the outlet tee to determine if there is any grease being discharged into the sanitary sewer.

If the inspector finds any visual issues with the system, they will ask to look at the maintenance logs to determine the last time the system was serviced in order to ensure maintenance activities are being performed. The records review will determine if Columbia Water requests that a FSE increase its maintenance schedule or develop a routine schedule if needed.

Maintenance Log for Cleaning XLS document template is available for download.