FOG Control Program

Program Overview

In 2016, Manatee County formally implemented a Fats, Oils, and Grease (FOG) Control Program as a means of reducing the levels of these substances in the sanitary sewer, and thereby reducing the number of sanitary sewer overflows (SSO) initiated by the presence of FOG.

FOG Control Program

The Utilities' Wastewater Compliance section is responsible for administering and enforcing the requirements of the FOG Control Program and its authority to do so is established by Manatee County's most current Sewer Use Ordinance (Division 3, Article II, Chapter 2-31 of the Manatee County Code of Ordinances - see link in box to the left).  Although predominantly focused on commercial food service facilities, the primary objective of the FOG Control Program is to educate the public on the easiest, most economical ways to prevent FOG from entering the sanitary sewer.

Why FOG is a Problem

When fats, oil and grease (FOG) are washed down the drain, they tend to coagulate and coalesce, and subsequently stick and build up on many surfaces within the sanitary sewer collection system.  Examples of FOG from animal or vegetable origin include, but are not limited to:  milk, cream, butter, lard, margarine, cheese, salad dressings, vegetable fats and oils, and fats in meats, cereals, seeds, nuts, and certain fruits.  When discharged into the sanitary sewer, FOG can cause sewer pipes to become partially or completely blocked, sewer pumping stations to fail, rancid odors to aggregate at pumping stations and sewer manholes, and sanitary sewer overflows (SSO) to occur, with their potential health hazards.  When FOG reaches the local water reclamation facility, their presence also hinders effective wastewater treatment.  Because Manatee County Utilities Department (MCUD) staff expend a significant amount of time to remove excess FOG from the sanitary sewer, the cost for that extra time is currently being passed on to MCUD customers in the form of elevated utility bills.

Where FOG Originates

The primary source for fats, oil and grease in the County's sanitary sewer is any place that food is prepared and/or cooked, and the wares to do so are subsequently washed.  While private residences fall into this category, their individual impact upon the sanitary sewer is relatively low; however, food service facilities, which prepare and/or cook food for a larger number of people, have the potential to generate significant amounts of FOG in a relatively short time, thereby creating a large individual impact upon the sanitary sewer.  A detailed definition for a food service facility is provided in the Manatee County Sewer Use Ordinance (see link to Sewer Use Ordinance in box to the left) and includes, but is not limited to, restaurants, lounges, bars, food courts, convenience stores, caterers, bakeries, ice cream and/or smoothie stores, coffee shops, hospitals, hotels, motels, nursing homes, churches, schools, detention centers, prisons, and mobile food vendors.

Preventing FOG Accumulation - Best Management Practices

The best way to prevent FOG from impacting the sanitary sewer is to prevent it from reaching the sanitary sewer in the first place.  Best Management Practices (BMPs) are defined as procedures and/or practices found to be the most effective and practical means of achieving an objective, while optimizing resources to do so.  The following BMPs may be implemented by any food service facility operator, or anyone who cooks or prepares food, to minimize the amount of FOG they discharge into the sanitary sewer.

  1. Implement a training program to educate kitchen staff and other employees about how they can help ensure BMPs are followed. People are more willing to support an effort if they understand the basis for it. Section 2-31-42(e)(6) of the Manatee County Sewer Use Ordinance (Division 3, Article II, Chapter 2-31 of the Manatee Code of Ordinances) requires all food service facilities to implement BMPs to minimize the discharge of FOG to the sanitary sewer system and to train employees on BMPs. 
  2. Post “NO GREASE” signs above sinks and on the front of dishwashers.  The signs will serve as a constant reminder for the staff working in the kitchen.
  3. Always use sink basket strainers to collect food wastes.  Solid waste disposal of food waste will reduce the frequency and cost of grease trap or interceptor cleaning.
  4. Always dry wipe pots and pans and dishware prior to dishwashing. This will reduce the amount of material going to the grease traps or Interceptors, which in turn will require less frequent cleaning, thereby reducing overall facility maintenance costs.
  5. Capture accumulated oil during the cleaning of stoves and ventilation exhaust hoods.  Dispose of this oil through solid waste disposal procedures after absorbing all free liquid.
  6. Use water temperatures less than 140º F in all the sinks.  Temperatures above 140º F will dissolve grease, but the grease can congeal or solidify in the wastewater collection system as the water cools. Reducing water temperature provides an added benefit for the food service facility by reducing energy costs used to heat the water.
  7. Eliminate the use of garbage disposals and/or food grinders. These devices put large quantities of solids into the collection and treatment systems, often causing blockages that result in wastewater back-ups.  If these devices must be utilized, Florida Plumbing Code requires that a solids interceptor be installed between the garbage disposal or grinder, and the grease interceptor or trap.
  8. Recycle waste cooking oil through an established, reputable recycling facility. The food service establishment may be paid for the waste material and will reduce the amount of garbage it must pay to have hauled away.
  9. Do not discharge caustics, acids, or solvents to the wastewater collection system. Caustics, acids and solvents can have other harmful effects on the wastewater treatment system and can be hazardous to employees working in the wastewater collection system.
  10. Do not use biological or emulsifying agents without written approval from the Director.  These products rarely solve a local grease problem, but instead pass it downstream in the sanitary sewer collection system.

Grease Interceptors

A grease interceptor is a multi-compartment grease control device constructed in different sizes, generally located outside of the building and underground between a food service facility and its connection to the County's sanitary sewer collection system, and primarily uses gravity to move wastewater as it segregates FOG (which float to the top) and food solids (which sink to the bottom) before discharging the remaining gray water to the sanitary sewer.  Each interceptor is equipped with (at a minimum) an access hatch and accompanying manhole over both the inlet and the outlet, to allow access at all times for inspection, sampling, monitoring, cleaning, and maintenance.  The capacity and sizing for grease interceptors must be compliant with the applicable requirements of both the Florida Plumbing Code and the Sewer Use Ordinance.  In all cases, however, the size of the grease interceptor must be sufficient to reduce the flow-through temperature of the gray water to less than 104° F (40° C).  Grease interceptors must be installed at all food service facilities, except where physical space is limited and a variance (see Related Forms above) has been granted to install a grease trap (see below).

Grease Interceptor Maintenance

Grease interceptors must be pumped, cleaned, and maintained by a waste hauler permitted by the County at least once every four (4) months.  During such maintenance, the hauler must ensure that all contents of the interceptor have been removed including floating materials, wastewater, bottom sludge, and solids.  Cleaning services must also include scraping excess solids from the walls, floors, baffles, and all pipework of the grease interceptor.  The practices known as "skimming" or "pump and return" are prohibited from being employed when pumping out any grease interceptor.  Each food service facility owner or operator is responsible for inspecting their facility grease interceptor during the pumping procedure, to ensure that it is properly cleaned, and that all fittings and fixtures inside of it are functioning properly.  Each food service facility is also responsible for all costs associated with installing, inspecting, pumping, cleaning, and maintaining its grease interceptor.

Each food service facility shall have its grease interceptor pumped, cleaned, and maintained when the following criteria are met:

  1. The floatable grease layer exceeds six inches (6”) in depth as measured by an approved dipping method;
  2. The settleable solids layer exceeds eight (8”) in depth as measured by an approved dipping method;
  3. The interceptor is not retaining/capturing FOG;
  4. The removal efficiency of the device, as determined through sampling and analysis, is less than eighty percent (80%).
  5. The discharge of FOG from the grease interceptor exceeds the County's local limits;
  6. The sum of the thickness of the floating grease layer plus the settleable solids layer, divided by the sum of the thickness of the floating grease layer plus the settleable solids layer plus the gray water layer, exceeds thirty percent (30%).

All wastes removed from each grease interceptor must be disposed of at a facility designed to receive such wastes or at a location designated by Manatee County for such purposes (see Hauled Waste Program).

Grease Traps

A grease trap is a grease control device which serves individual fixtures (such as a 3-compartment sink), has only a limited effect, and is used in locations where a variance (see Related Forms above) has been granted because installation of a grease interceptor is determined to be impossible or impractical; however, a grease trap may also be used in conjunction with a grease interceptor.   A grease trap primarily uses gravity to move wastewater through it, and includes a series of baffles which serve to slow the wastewater as it segregates FOG (which float to the top) and food solids (which sink to the bottom) before discharging the remaining gray water to the sanitary sewer. The capacity and sizing for grease traps must be compliant with the applicable requirements of the Florida Plumbing Code and the Sewer Use Ordinance.  Every grease trap is vented and equipped with: a removable lid or cover on the top surface for inspection, sampling, cleaning, and maintenance; a mechanism for secure closing of the lid or cover; and a device to control the rate of flow through the unit. No water or wastewater with a temperature in excess of 140° F (60° C) may be discharged into any grease trap.

Grease Trap Maintenance

Cleaning and maintenance of grease traps must be performed when the total volume of captured grease and solid material displaces more than 30% of the total volume of the unit. Although cleaning and maintenance may be completed by either a waste hauler permitted by the County, or a designated representative of the food service facility, each grease trap must be opened, inspected, cleaned, and maintained at least once every week in accordance with written BMPs developed by the food service facility for their grease trap.  The original design of the grease trap may not be modified unless the manufacturer of the grease trap recommends the modification in writing. Grease and solid materials removed from a grease trap must be disposed of in the solid waste disposal system of the food service facility, or at a grease recycling or disposal facility.


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