§ 20.20

'Grease trap' means a multi-baffle, single compartment, 10 to 50 gallon capacity device, serving one (1) to a maximum of four (4) fixtures designed for the removal of FOG from food service establishment discharges and installed prior to the effective date of this ordinance.

'Hydromechanical grease interceptor' means a plumbing appurtenance or appliance that is installed in a sanitary drainage system to intercept FOG from a wastewater discharge and is identified by flow rate, separation and retention efficiency. The design incorporates air entrainment, hydromechanical separation, interior baffling, and/or barriers in combination or separately, and one of the following:

A. External flow control with air intake (vent); directly connected.

B. External flow control without air intake (vent); directly connected.

• C. Without external flow control; directly connected.

• D. Without external flow control; indirectly connected.

'Interference' means a discharge which, alone or in conjunction with a discharge or discharges from other sources:

A. Inhibits or disrupts the POTW, its treatment processes or operations, or its sludge processes, use or disposal; and

B. Is therefore a cause of a violation of any requirement of the POTW's NPDES permit (including an increase in the magnitude or duration of a violation) or of the prevention of sewage sludge use or disposal in compliance with the following statutory provisions and regulations or permits issued thereunder (or more stringent state or local regulations): Section 405 of the Clean Water Act, the Solid Waste Disposal Act (SWDA) [including Title II, more commonly referred to as the Resource Conservation and Recovery Act (RCRA), and including the state regulations contained in any sludge management plan prepared pursuant to Subtitle D of the SWDA], the Clean Air Act, and the Marine Protection, Research and Sanctuaries Act.

C. Inhibits operation, disrupts or causes a condition within the sanitary sewer system that may cause excessive maintenance or a sanitary sewer overflow.

'Sanitary sewer overflows (SSO)' means any overflow, spill, release, discharge or diversion of untreated or partially treated wastewater from a sanitary sewer system. SSO include:

A. Overflows or releases of untreated or partially treated wastewater that reach waters of the United States.

B. Overflows or releases of untreated or partially treated wastewater that do not reach waters of the United States.

C. Wastewater backups into buildings and onto private properties that are caused by blockages or flow conditions within the publicly owned portions of a sanitary sewer system.

'Significant industrial user (SIU)' means that except where the control authority of a POTW has found an industrial user to be exempt pursuant to 40 CFR 403.3(v)(2) and (v)(3):

A. All industrial users subject to categorical pretreatment standards under 40 CFR 403.6 and 40 CFR Chapter I, Subchapter N; and

B. Any other industrial user that discharges an average of 25,000 gallons or more of process wastewater to a POTW (excluding sanitary, non-contact cooling and boiler blowdown wastewater); contributes a process wastestream which makes up 5 percent or more of the average dry weather hydraulic or organic capacity of the POTW treatment plant; or is designated as such by the POTW control authority on the basis that the industrial user has a reasonable potential for adversely affecting the POTW operation or for violating any pretreatment standard or requirement.