(A) Grease interceptors shall be installed by users as required by the town Director of Public Works (“Director”) or his or her designee. Grease interceptors shall be installed at the user’s expense, when such user operates a cooking establishment. Grease interceptors may also be required in non-cooking or cold dairy and frozen foodstuffs establishments and other industrial or commercial establishments when they are deemed necessary by the Director for the proper handling of liquid wastes containing grease. No user shall allow wastewater discharge concentration from subject grease interceptor to exceed 325 milligrams per liter, as identified by method EPA Method 1664 or 275 milligrams per liter, as identified by EPA Method 413. All grease interceptors shall be of a type, design and capacity approved by the Director or his or her designee and shall be readily and easily accessible for user cleaning and town inspection. All such grease interceptors shall be serviced and emptied of accumulated waste content as required in order to maintain minimum design capability or effective volume of the grease interceptor, but no more than 75% of the total capacity of the grease interceptor. Users who are required to pass water through a grease interceptor shall:
(1) 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 baffles with 20% of the total volume of the grease interceptor being allowed for sludge to settle and accumulate, identified hereafter as a “sludge pocket”;
(2) Remove any accumulated grease cap and sludge pocket as required, but at intervals of not longer than 30 days at the user’s expense. Grease interceptors shall be kept free of inorganic solid materials such as grit, rocks, gravel, sand, eating utensils, cigarettes, shells, towels, rags and the like, which could settle into this pocket and thereby reduce the effective volume of the grease interceptors.
(3) Accept the following conditions: if any skimmed or pumped wastes or other materials removed from grease interceptors are treated in any fashion on-site and reintroduced back into the grease interceptor as an activity of and after the on-site treatment, the user shall be responsible for the attainment of established grease numerical limit consistent with and contained in division (A) above on all discharges of wastewater from the grease interceptor into the town sanitary sewer collection and treatment system.
(4) Operate the grease interceptor in a manner so as to maintain the device such that attainment of the grease limit is consistently achieved. CONSISTENT shall mean any wastewater sample taken from the grease interceptor shall be subject to terms of numerical limit attainment described in division (A) above. If an establishment desires, because of documented space constraints, an alternate to an out-of-building grease interceptor, the request for an alternative location shall contain the following information:
(a) Location of town sewer main and easement in relation to available exterior space outside the building; and
(b) Existing plumbing at or in a site that uses common plumbing for all services at that site.
(B) The use of biological additives as a grease degradation agent is conditionally permissible, upon prior written approval by the Director. Any establishment using this method of grease abatement shall maintain the trap or interceptor in such a manner that attainment of the grease wastewater discharge limit, as measured from the trap’s outlet, is consistently achieved.
(C) The use of automatic grease removal systems is conditionally permissible, upon prior written approval by the Director and the Cabarrus County Health Department. Any establishment using this equipment shall operate the system in such a manner that attainment of the grease wastewater discharge limit, as measured from the unit’s outlet, is consistently achieved.
(D) The Director reserves the right to make determinations of grease interceptor adequacy and need, based on review of all relevant information regarding grease interceptor performance, facility site and building plan review and to require repairs to, modification or replacement of such traps.
(E) The user shall maintain a written record of trap maintenance for three years. All such records will be available for inspection by the town at all times.
(F) No non-grease-laden sources (such as non-grease wastewater from toilets and showers) are allowed to be connected to sewer lines intended for grease interceptor service.
(G) Access manholes, with a minimum diameter of 24 inches, shall be provided over each chamber and sanitary tee. The access manholes shall extend at least to the finished grade and be designed and maintained to prevent water inflow or infiltration. The manholes shall also have readily removable covers to facilitate inspection, grease removal and wastewater sampling activities.
(Ord., passed 5-11-09)