(A) Grease, fats and oil interceptors shall be installed and maintained by users operating food cooking establishments. Grease interceptors may also be required in food non-cooking establishments and other industrial or non-domestic users when, in the opinion of the Building Inspector, they are necessary for the proper handling of wastewater containing excessive amounts of grease, fats, and oils; except that such interceptors shall not be required for residential users. Interceptors shall be installed and maintained at the user’s expense. If no grease is found through investigation by the City Inspector(s) at a food establishment, a grease trap may not be required.
(B) No user shall allow any wastewater discharge concentration from the interceptor to exceed 325 milligrams per liter (EPA Method 1664) or 275 milligrams per liter (EPA Method 413) in fats, oils, and greases. These limits shall be consistently maintained.
(C) All interception units shall be of type and capacity approved by the Building Inspector and shall be so located to be easily accessible for cleaning, inspection, and wastewater effluent sampling. Such interceptors shall be inspected, cleaned of grease, sludge, debris and the like and repaired as required in order to maintain minimum design capability of the grease interceptor, but not less often than every 30 days if grease problems are found. This maintenance shall be performed by the user at their expense. The Building Inspector will allow the use of an automatic grease separator system under the following conditions:
(1) A food establishment has physical limitations creating a hardship condition which prohibits installing a properly sized in-ground grease trap.
(2) The sizing of an automatic grease separator system will be according to the manufacturer’s specifications.
(3) The food establishment manager/staff signs a log certifying each daily, weekly, and quarterly maintenance of the automatic grease separator system has been done according to the manufacturer’s specifications.
(D) The POTW Director, in his or her discretion, may grant a variance to a user as it relates to the required grease trap/interceptor cleanout requirements based upon certified documentation that the requirements of this chapter impose an unnecessary or unreasonable burden on the user. The POTW Director may rescind or modify such variance if the quantity or concentration of the user’s discharge has changed or causes a detriment to the city’s sewer collection system.
(E) Access manholes, with a minimum diameter of 24 inches shall be provided over each interceptor chamber and sanitary tee. The access manholes shall extend at least to finished grade and be designed and maintained to prevent water inflow and infiltration. The manholes shall also have readily removable covers to facilitate inspection, grease removal, and wastewater sampling activities.
(F) Minimum design capability of the interceptor must be in accordance with the North Carolina edition of the International Plumbing Code and provide for a minimum hydraulic retention time of 24 minutes at actual peak flow or 12 minutes at the calculated theoretical peak flow rate as predicted by the Uniform Plumbing Code fixture criteria, between the influent and effluent baffle with 20% of the total volume of the grease interceptor being allowed for sludge to settle and accumulate.
(G) Grease interceptors that are 50 pounds or larger in size must be cleaned out commercially. The food establishments that clean their own small grease traps (less than 50 pounds) shall put the grease in a sealed container and dispose of it as set forth in state regulations. The grease, fats and oils removed from a grease interceptor must be put in an appropriate container and properly disposed of as solid waste or recycled commercially. The Building Inspection will evaluate and determine the cleaning frequency of under-the-sink traps. Care must be taken to prevent grease, fats, and oils from entering the stormwater system or sanitary sewer system. No non-grease laden sources are allowed to be connected to any sewer line intended for grease interceptor service.
(H) The user shall maintain a written record of interceptor maintenance for three years. All such records will be available for inspection by the city at all times. The user shall submit written reports of such maintenance when requested by the city. The user shall refer to the Grease Trap User Guidance Manual for information on permitting requirements, forms, non-compliance fines, and the like.
(I) Any user required to install or upgrade a grease interceptor by the Building Inspector must complete the installation/upgrade of the grease interceptor within six months after written notification from the Building Inspector. Adequately sized grease traps shall be required for any new grease trap installation at new food establishments no prohibited by space constraints. The size, type, and location of the grease interceptor shall be approved by the Building Inspector. If an obstruction of a city sewer main(s) occurs that causes a sanitary sewer overflow and the overflow can be attributed in part to the user, the user shall be required to install or upgrade a grease interceptor within 30 days after written notice from the city. In cases of sanitary sewer overflows, the city shall take appropriate enforcement actions, as set forth in the city’s industrial pretreatment enforcement plan and the sewer use ordinance, against the user.
(J) Existing undersized grease traps in use at food establishments will be evaluation on the following:
(1) The products sold by the food establishments will be evaluated by City Inspector(s). The Inspector will be given the discretion to allow or resize an existing grease trap.
(2) An existing undersized grease trap may require an increased cleaning schedule.
(3) All final decisions regarding an undersized grease trap will be determined by the Chief Building Inspector.
(Ord. 2001-10, passed 1-16-01; Am. Ord. 2007-45, passed 6-4-07)