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BUILDING DIVISION Bulletin No. 01-01

July 2001

Grease Traps And Interceptors

The City of Surrey, like most municipalities, continues to experience sewer blockages caused by the accumulation of grease on the surfaces of sewer lines. Greasy wastewater can be discharged to the sewer system from several sources, including food service operations. In order to reduce sewer blockages, food service operations in the City of Surrey that discharge wastewater containing grease must install a grease trap or interceptor. These operations include any businesses that have deep fryers or grills, prepare or cook products containing meat or grease from other sources, or require a grease extracting hood. Sub-section 4.4.3.(1) of the B.C. Plumbing Code states Where a fixture discharging sewage that includes grease is located in a public kitchen or restaurant or in an institution a grease interceptor shall be installed when required. Greater Vancouver Sewerage & Drainage District has introduced a Code of Practice for wastewater management at food sector establishments under Sewer Use By-law No. 164 Schedule D which was adopted on July 28, 2000. Section 4.3.11 of Sewer By-law No. 164 states that: The operator of a Food Sector Establishment must keep and maintain at the Food Sector Establishment a record of all Grease Interceptor inspections and maintenance carried out, recording the date of inspection, the date of cleaning or maintenance, the type and quantity of material removed from the Grease Interceptor and the disposal location. The inspection and maintenance record must be retained for a period of two years and must be available for inspection by an Officer. Exemptions Food service operations that do not generate grease or solids will not require a grease trap or interceptor. These operations include, but are not limited to, the following: Bakeries (no deep frying) Canteens Coffee Shops Juice Bars Delicatessens (extracting hood not required) Fish Shops Meat Sales Fruit and Vegetable Markets Sandwich Bars Muffin Shops Pretzel Shops Bagel Shops

City of Surrey Planning & Development Department, 14245 - 56 Avenue, Surrey, B.C. V3X 3A2 Telephone: 591-4441

City of Surrey Planning & Development Department

Any other operations in Surrey not listed that believe they do not generate wastewater containing grease or solids, may request an exemption by contacting the Plumbing Section at 604-591-4245.


Design All grease traps and interceptors must be designed using standard engineering principles for sedimentation and floatation in gravity separators. Baffles and good inlet design are required to deflect the flow across the surface areas of the units and sufficient grease and solids storage capacity is required. Grease traps and interceptors shall be rated for the designed flow-through rate of the unit in gallons/minute or litres/minute. All grease traps and interceptors shall be installed indicating the flow rates of the units. The label must be permanent and must be visible after installation. Sizing Grease traps and interceptors shall be sized according to the sum of the surge flow rates from all the plumbing fixtures connected to the grease trap or interceptor. The following fixtures in the kitchens, food preparation areas or clean-up areas must be connected to the grease trap(s) or interceptor: All sinks (hand basins optional) Wash down hoods Floor drains Chinese cookers Floor drains under garbage compactors (food waste only) Any other fixture that accepts wastewater that contains grease or solids · Dishwashers and garbage grinders shall not be connected to the interceptor.

The size of the interceptor or trap shall be determined form the sum of the surge flow rates from the fixture units connected to the grease trap or interceptor but no smaller than 50 gpm. Use the following tables for surge flow rates: FIXTURE UNIT Litres/Minute Hand Sink Restaurant Kitchen Sink Single Compartment Scullery Sink Double Compartment Scullery Sink Triple compartment Sink Two Single Compartment Sink Two Double Compartment Sink Floor Drain

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SURGE FLOW RATE U.S. Gallons/Minute 7.5 15 20 25 30 25 30 5 Imp Gallons/Minute 6.2 12.5 16.7 20.9 25.1 20.9 25.1 4.2

28 57 76 95 114 95 114 19

City of Surrey Planning & Development Department

For all other fixture units, the surge flow rates will be rated according to the fixture outlet or trap size. OUTLET OR TRAP SIZE Inches 1.25 1.5 2.0 2.5 3.0 4.0 · · · · · · · Millimetres 32 38 51 64 76 102 Litres/Minute 28 57 83 114 142 170 SURGE FLOW RATE U.S. Gallons/Minute 7.5 15 22 30 37.5 45 Imp. Gallons/Minute 6.2 12.5 18.3 25.1 31.2 37.4

Calculate the sum of the surge flow rates from all fixtures connected to a grease trap or interceptor using the tables above. Design or select a pre-manufactured trap or interceptor rated to handle the total surge flow. The sum of the surge flow rates of fixtures discharging to a grease trap or interceptor shall not exceed the designed flow rate of the unit. More than one grease trap or interceptor may be used in any operation to accommodate the flows. Grease traps and interceptors rated at less than 50 gallons per minute will not be permitted. Outside concrete grease interceptors shall have a liquid capacity of not less than 500 litres (150 U.S. Gallons). Grease traps and interceptors should be located outside whenever possible. If there is not space available outside, then the units should be located as close to the service door as possible. Outside units shall be situated so that storm water run-off cannot enter the grease interceptor.

SERVICING Servicing and maintenance is essential for the efficient operation of grease traps and interceptors. Servicing frequency is site-specific and is dependent on the amount of oil and grease and suspended solids generated at each operation and the size of the grease trap or interceptor. The volumes of greases and solids in grease traps and interceptors must not exceed the designed grease and solids storage capacity of the unit. Grease traps and interceptors should be inspected weekly and cleaned out on a minimum frequency of once every three months or more frequently as required. It is recommended that larger traps and interceptors than those required should be considered by the food service operator to increase the grease and solids storage capacities in the units. The initial costs for the installation of larger units are greater, however, the frequency of cleaning and disposal will be reduced. The cost savings for cleaning and disposal can pay for the increased size of the trap or interceptor, particularly in high-volume restaurants.

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City of Surrey Planning & Development Department


Existing food sector establishments will be exempt unless the grease traps or interceptors are clearly undersized, the operation creates maintenance problems in local sewers, or there are major renovations to the cooking areas or major upgrades to kitchen equipment. Grease interceptors that do not meet the minimum capacity requirements will have a period of 3 years from July 28, 2000, to install and connect grease interceptors having the minimum capacity requirements as required by the sizing section of this Bulletin. This Bulletin is provided as a guide only. For complete details see G.V.R.D. Sewer Use By-law No. 164 ScheduleD. Code of Practice for Wastewater Management at Food Sector Establishments.

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City of Surrey Planning & Development Department

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