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Grease Interceptor Program - Requirements
Approval of Grease Interceptors
All grease interceptors must be approved by the LFUCG Division of Engineering prior to installation.
This is to ensure that the interceptor meets sizing requirements, construction standards and conforms
to plumbing codes. The following information must be submitted to Division of Engineering - New
Development Section, Commercial Projects Coordinator, to obtain approval and be issued a grease
interceptor permit.
- Proposed interceptor location
- Proposed size of grease interceptor
- Detailed drawing of interceptor and piping
- Number and type of fixtures proposed to be attached
After approval, the facility will be issued a grease interceptor permit and the grease interceptor
can be installed. The Division of Engineering will inspect the grease interceptor after installation
is complete. The grease interceptor permit must be kept on file at the facility.
Proper Sizing
In order to perform correctly, grease interceptors must be adequately sized. The Division of Sanitary
Sewers requires that all grease interceptors provide a minimum of 12 minutes retention time at
theoretical peak flow rate. The following chart can be used to calculate the theoretical peak flow
rate based on fixtures connected to the interceptor.
Peak flow rate values by fixture
type
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Fixture Unit
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Peak Flow Rate (Gallons/Minute)
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Hand Sink
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7.5
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Restaurant Kitchen Sink
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15
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Single Compartment Scullery sink
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20
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Double Compartment Scullery Sink
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25
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Triple Compartment Sink
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30
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Two Single Compartment Sinks
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25
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Two Double Compartment Sinks
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30
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Floor Drain
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5
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Dishwasher
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Manufacturer’s Peak Discharge Rate
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Design Requirements
As per LFUCG ordinance requirements, grease interceptors shall be constructed of impervious materials
capable of withstanding abrupt and extreme changes in temperatures, shall be of substantial
construction, watertight and equipped with easily removable covers. The interceptor shall contain a
baffle system, which adequately diverts and slows the flow to avoid short-circuiting. Interceptors located
in roadways or parking lots should be traffic rated.
Maintenance
Grease interceptors should be cleaned on a regular basis to ensure efficient operation. The Division of
Sanitary Sewers requires that they be cleaned no less than twice per year. The necessary frequency of
cleaning will vary greatly depending on the nature of the establishment. Factors such as types of food,
cooking methods, cleaning techniques, carry-out verses dine-in, all will determine volume of grease
discharged. Facilities with high grease loadings may have to clean their interceptors as often as monthly.
Facilities with under-sized interceptors, especially under-the-counter units, may have to clean weekly or
even daily. Many of the techniques found in the
Best Management Practices Section of this manual should be
helpful in the reduction of grease discharges, and thus reduced the frequency of grease interceptors
cleanings.
To properly clean a grease interceptor, the entire contents (liquids and solids) must be pumped out.
Leaving accumulated solids in the bottom of grease interceptors can lead to short circuiting and reduced
retention times, as well as, very unpleasant odors.
Maintenance of external large capacity grease interceptors should be performed by qualified grease or
septic haulers. These services typically will empty the entire contents with a pumper truck and haul
the grease and sludge to an approved disposal site. A list of local
septic/grease haulers is available
on our website. Smaller under counter grease interceptors can be cleaned by in-house staff. Refer to
manufacturers cleaning procedure as cleaning methods may vary with type of unit.
The Division of Sanitary Sewers requires that cleaning events be recorded and kept on file. See
Appendix A, for an example maintenance log.
Record Keeping
Maintenance and cleaning events must be recorded in written form and kept on file on site. Receipts or
manifests from private pumping septic and grease haulers should indicate destination of hauled waste,
i.e. Town Branch WWTP, Lexington KY. The records shall be made available to LFUCG Division of Sanitary
Sewer inspectors upon request. Maintenance records shall contain the following information:
- Date of Maintenance
- Person performing maintenance
- Estimated volume of grease removed
- Disposal location, Example: Grease recycle bin, Town Branch WWTP, etc.
- Manager’s signature or initials for verification
A copy of the Grease Interceptor permit issued by the Division of Engineering shall be kept on file
at the facility the permit has been issued to.
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