HomeMy WebLinkAboutO - Fats, Oil and GreaseCity of South Burlington
Division of Water Pollution
Control
Fats, Oil and Grease
I. Introduction
Fats, oil and grease in the sewer system is the source ofmany sewer
line blockages and sewer overflows in South Burlington. Many man
and equipment hours are dedicated to unclogging these lines. Animal
and vegetable-based oil and grease most often enter the sewer system
in their melted form. In the sewer system these fats and oil cool and
solidify. This solidified grease collects on the walls ofthe sewer line
resulting in reduced capacity, line blockages and sanitary sewer
overflows.
Sewer overflow are a very serious matter. These overflow events
discharge raw untreated sewage onto public and private properties and
into our local streams and rivers. Nation wide, 30 to 35 % of all sewer
overflows is caused by fats, oil and grease blockages. In an effort to
resolve this problem, the City of South Burlington has developed a
grease control program.
The program will combat the grease problem through regulation,
education,inspections and enforcement.In April of200 1 the south
Burlington city council adopted an ordinance amendment regarding
the use of grease, oil, and sand separators by city businesses.
During the last year, the city has experienced multiple back-ups of
sanitary sewage into private homes caused by a build-up of grease in
the sewer mains. While the existing ordinance required your business
to have a grease trap, the amendment establishes permitting and
enforcement procedures to go into effect December 1, 2001.
II. Grease Interceptor Requirements:
Permitting
• The application should be sent to Ray Belair, Code Enforcement
Officer, 575 Dorset Street, South Burlington, Vermont 05403
• There is no permit fee.
• You may include multiple grease traps on one permit provided all
appropriate plans are supplied.
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• The permit issued by the city will not expire. However, if you
make changes to an existing grease trap or install a new one, a new
permit will be required.
Proper Sizing
In order to perform correctly, grease interceptors must be adequately
sized. The City of South Burlington 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
Fixture Unit Peak flow Rate (Gallons/Minute)
Hand Sink 7.5
Restaurant Kitchen sink 15
Single Compartment Scullery Sink 20
Double Compartment Sink 25
Triple Compartment Sink 30
Two single Compartment Sinks 25
Two Double Compartment Sinks 30
Floor Drain 5
Dishwasher Manufacturer's Peak Discharge Rate
Exceptions to minimum sizing requirements
Some facilities may be granted exemption from minimum sizing
requirements ifthey can demonstrate that space restrictions preclude the
installation ofa properly sized interceptor. In extreme situations,
financial hardship nlay be considered as a course for exemption. In
evaluation offinancial hardship situations, the Division ofWater
Pollution control will consider the installation costs verses the grease
removal benefit and weather or not other suitable options are available.
The final decision will be made by the city.
Design Requirements
Grease interceptors shall be constructed of constructed of impervious
material capable ofwithstanding extreme changes in temperature, shall
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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 parking lots should be traffic rated.
Maintenance
Grease interceptors should be cleaned on a regular basis to ensure
efficient operation. The necessary frequencies of cleaning will vary
depending on the nature of the facility. Factors that may affect cleaning
frequency types of food, cooking methods, cleaning techniques, cany-out
verses dine-in, and all will determine the volume of grease discharged.
Facilities with high grease loadings may need to clean their interceptors
as often as monthly. Facilities with undersized interceptors, especially
under-the-counter units, should clean their interceptors weekly or even
daily.
To properly clean a grease interceptor, the entire contents (liquid and
solid) need to be pumped out. Leaving accumulated solids in the bottom
of grease interceptors can lead to short-circuiting and reduce retention
times, as well as, producing unpleasant odors.
Maintenance of extemallarge grease interceptors should be performed by
qualified grease or septic haulers. These services will empty the entire
contents with a pumper truck and haul the grease to an approved site. The
following is a list ofhaulers with an agreement with the Division of
Water Pollution Control, South Burlington.
Haulers listed in alphabetical order Phone
Bundy's sewer & Drain Service Inc. 862-2245
Hartigan Co. 800-696-0761
P & H Senesac, Inc. 863-6322
P & P Septic Service, Inc. 658-6243
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Record Keeping
Maintenance and cleaning records may be kept in any form you wish and
kept on file on site. Receipts or manifests from private pumping septic
and grease haulers should indicate destination ofhauled material. The
records shall be made available to South Burlington inspectors upon
request. Maintenance records should contain the following information.
• Date ofMaintenance
• Item Removed
• Approximate amount removed
• Disposal Location
• Authorized Signature or initials for verification
A copy ofthe grease interceptor permit issued by the City of South
Burlington shall be kept on file at the facility the permit has been issued to.
Proper placement ofInternal Grease Traps
The placement of internal grease traps is the key solution to grease removal.
The largest point source of grease to the sewer system is through the dish
cleaning area, especially the pre-rinse cycle before the dishwasher. If a
facility uses a three compartment sink for dish and cookware cleaning, then
the three compartment sink would be the best place for the grease trap. Some
facilities with multiple sources of grease may need to install more than one
grease trap. Food disposals should not be connected to the grease trap or
interceptor.
III. How does a Grease Interceptor Or Trap Work
A grease interceptor or trap is a device designed to slow the flow of grease
laden waters to allow for gravity separation. The unit contains a baffle
system, which redirects and slows the flow of water. Good separation
requires a minimum of 12 minutes detention time, based on the peak flow
rate. Water entering the unit takes 12 minutes to exit the unit. This is enough
time to allow for the majority of grease to float and be trapped in the baffle
system, and for the solids to settle to the bottom of the unit.
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Sample Grease Interceptor
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IV. Best Management Practices
Fats, oil and grease can be managed effectively in the food service industry
to minimize the discharge of grease to the sewer system and decrease the
required maintenance of grease interceptors. By preventing them from
entering the waste system you reduce the burden on the grease interceptor
and then reducing maintenance time, costs and disposal fees.
Train Kitchen Staff:
Train Kitchen staff in management practices and methods to reduce the
volume of grease discharged to the sanitary sewer system. Train personal to
be aware ofproblems created by grease in the sewer system, possible
violations, fines and cost of cleaning clogged pipes. Even the smallest
amount of grease on each pot, pan, or plate can be substantial when you
serve hundreds of meals per day.
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• Post" NO GREASE" Signs
• Dry Wipe Pots Pans and Dishware Prior to Dishwashing
• Do Not Dispose of Waste Food Through a Garbage Disposal
• Clean Grease Interceptor Routinely and Keep Records
• Witness Cleaning and Maintenance Procedures
• Inspect the Grease Interceptor During Maintenance
Enforcement
The amendment (Section 4) establishes enforcement procedures. The city
code enforcement officer, and other designated city officials, will be able to
write citations for the penalties indicated ifyour business is found to be in
violation ofthe ordinance.
Attached is a sample maintenance log and also a copy of
the ordnance.
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