Title 124 - Rules And Regulations For The Design, Operation And Maintenance of Onsite Wastewater Treatment Systems
Chapter 9 - Grease Trap Tank

001 A restaurant or non-dwelling facility involved in food preparation shall have a separate wastewater line to a grease trap tank for the food preparation and dishwashing wastes. Any wastewater line for graywater and non-kitchen blackwater including restroom and toilet wastes shall not be connected to the grease trap tank. The grease trap tank shall be located ahead of the septic tank. An existing restaurant or non-dwelling facility involved in food preparation that is replacing or modifying its onsite wastewater treatment system may install an additional septic tank in the waste line in lieu of a grease trap tank provided the following conditions are met:

001.01 The restaurant or non-dwelling facility was constructed before the effective date of these regulations;

001.02 The current kitchen and blackwater waste streams are not separated;

001.03 The additional septic tank is sized following Section 004 below; and

001.04 The additional tank is placed in series with other tanks and all tanks comply with all other requirements of this Title.

002 Materials and Specifications

002.01 An external grease trap tank shall be watertight, durable, and constructed of the same materials as septic tanks.

002.02 The inlet invert shall be at least three inches above the outlet invert.

002.03 The inlet baffle or sanitary tee shall extend at least 24 inches below the liquid level.

002.04 The outlet baffle or sanitary tee shall extend to within eight inches of the tank bottom.

002.05 The grease trap tank shall be provided with an inspection or clean out cover over the inlet and outlet.

002.06 Blackwater other than kitchen waste shall not be connected to a grease trap tank.

002.07 All wastewater from the kitchen operation shall be connected to the external grease trap tank. The effluent from the grease trap tank shall connect to the inlet line of the septic tank.

003 Operation and Maintenance

003.01 The grease trap tank shall be operated properly and maintained, inspected, and cleaned regularly for proper functioning of the grease trap tank to prevent the escape of appreciable quantities of grease.

003.02 Accumulated fats, oils, grease, and solids shall be removed when these exceed 50 percent or more of the wetted height of the grease trap, as measured from the bottom of the grease trap to the invert of the outlet pipe.

004 Sizing a Grease Trap Tank

004.01 A grease trap tank shall provide twenty four hours of detention time for the average daily flow.

004.02 The minimum capacity of any grease trap tank shall be 750 gallons.

Enabling Legislation: Neb. Rev. Stat. ยง81-1505(8).
Legal Citation: Title 124, Ch. 9, Nebraska Department of Environmental Quality.