What can businesses do to keep Greensboro's sewers fat-free?
Local food preparation establishments can keep grease out of their plumbing system and the City's sewer system by following the Best Management Practices listed below.
Practice Dry Cleanup
Workers should be strongly encouraged to use dry cleanup methods to remove fats, oils, and grease from surfaces before washing with water. Remove food waste from cooking surfaces and utensils by scraping, wiping, or sweeping rather than washing with water. Use rubber scrapers to remove fats, oils, and grease from cookware and serving surfaces. Use food grade paper to soak up oil and grease under fryer baskets. Use paper towels to wipe down work areas. Disposal and recycling containers should be placed in easy reach of kitchen employees.
Install a Grease Interceptor or Grease Trap
New food preparation establishments are required to install an appropriately sized "grease retention unit," as required by the International Plumbing Code. However, existing facilities that do not have a grease retention unit and that have frequent problems with grease backups and blockages may want to consider installing such a unit.
A grease retention unit is a chamber designed for wastewater to pass through and allow free or emulsified oil to float to the top for retention as the remainder of the effluent passes through. There are two types of grease retention units: grease interceptors and grease traps.
A grease interceptor is a vault, located on the exterior of the building, with a minimum capacity of between 750 and 1,000 gallons. The vault includes at least two compartments with the flow between each compartment through a 90° fitting designed for grease retention. The capacity of the interceptor provides adequate residence time so that the wastewater has time to cool, thus allowing time for any remaining grease not collected by the traps to congeal and rise to the surface where it accumulates until the interceptor is cleaned.
Grease traps are typically "under the counter" grease retention units which are normally less than 100 gallon capacity. Grease traps are usually limited to handle discharge from a maximum of four fixtures, not to exceed 50 gallons per minute combined discharge rate.
Maintain your grease retention unit
It is important to establish a regular maintenance schedule to ensure that grease accumulation does not hinder the operation of the device. The Water Resources Department advocates the use of the "25 percent rule" when determining grease retention unit maintenance intervals. A grease retention unit will not meet performance standards once the accumulation of floatable FOG material and settled solids have reached a depth equal to or greater than 25 percent of the total operating depth of the grease retention unit.
In fact, a grease interceptor's performance severely declines once these accumulations exceed 15 percent of the total liquid depth. As a guideline, food preparation establishment owners/operators should conservatively set their cleaning frequency such that accumulations do not exceed 20 percent of the total liquid depth of the grease interceptor.
Dispose of Grease Renderings Responsibly
Dispose of grease renderings collected from fryers and other cookware in a designated outdoor container. Waste haulers or grease disposal companies will often provide a waste container for this purpose. Safeguard your rendering container from the possibility of leaks or spills. These containers should be located away from storm drain catch basins and covered to prevent contact with nearby storm waters during a rain event or spill. Immediately clean up any grease spills or leaks to prevent discharge into the storm drain and minimize the presence of vermin. Never dump grease renderings in the street, wet retention ponds, or into storm drains. These actions are against the law and could result in fines or discontinuance of sewer service.
Want to Know More?
For more information about implementing BMPs in your establishment or to request a Fats, Oils, and Grease information packet, call the Fats, Oils, and Grease hotline at 336-412-6321.
The City's Fats, Oils, and Grease coordinator is available for educational presentations and training workshops for food preparation establishments.