As used in this subpart:

Affected source means the group of all equipment that comprise the POTW treatment plant.

Cover means a device that prevents or reduces air pollutant emissions to the atmosphere by forming a continuous barrier over the waste material managed in a treatment unit. A cover may have openings (such as access hatches, sampling ports, gauge wells) that are necessary for operation, inspection, maintenance, and repair of the treatment unit on which the cover is used. A cover may be a separate piece of equipment which can be detached and removed from the treatment unit, or a cover may be formed by structural features permanently integrated into the design of the treatment unit. The cover and its closure devices must be made of suitable materials that will prevent exposure of the waste material to the atmosphere and will maintain the integrity of the cover and its closure devices throughout its intended service life.

Existing source or existing POTW means a POTW that commenced construction on or before December 1, 1998, and has not been reconstructed after December 1, 1998.

Fraction emitted means the fraction of the mass of HAP entering the POTW wastewater treatment plant which is emitted prior to secondary treatment.

Group 1 POTW means a POTW that accepts a waste stream regulated by another NESHAP and provides treatment and controls as an agent for the industrial user. The industrial user complies with its NESHAP by using the treatment and controls located at the POTW. For example, an industry discharges its benzene-containing waste stream to the POTW for treatment to comply with 40 CFR part 61, subpart FF—National Emission Standard for Benzene Waste Operations. This definition does not include POTW treating waste streams not specifically regulated under another NESHAP.

Group 2 POTW means a POTW that does not meet the definition of a Group 1 POTW. A Group 2 POTW can treat a waste stream that is either:

(1) Not specifically regulated by another NESHAP, or

(2) From an industrial user that complies with the specific wastewater requirements in their applicable NESHAP prior to discharging the waste stream to the POTW.

Industrial user means a nondomestic source introducing any pollutant or combination of pollutants into a POTW. Industrial users can be commercial or industrial facilities whose wastes enter local sewers.

New source or new POTW means any POTW that commenced construction or reconstruction after December 1, 1998.

Publicly owned treatment works (POTW) means a treatment works, as that term is defined by section 112(e)(5) of the Clean Air Act, which is owned by a municipality (as defined by section 502(4) of the Clean Water Act), a state, an intermunicipal or interstate agency, or any department, agency, or instrumentality of the federal government. This definition includes any intercepting sewers, outfall sewers, sewage collection systems, pumping, power, and other equipment. The wastewater treated by these facilities is generated by industrial, commercial, and domestic sources. As used in this subpart, the term POTW refers to both any publicly owned treatment works which is owned by a state, municipality, or intermunicipal or interstate agency and, therefore, eligible to receive grant assistance under the Subchapter II of the Clean Water Act, and any federally owned treatment works as that term is described in section 3023 of the Solid Waste Disposal Act.

POTW treatment plant means that portion of the POTW which is designed to provide treatment (including recycling and reclamation) of municipal sewage and industrial waste.

Secondary treatment means treatment processes, typically biological, designed to reduce the concentrations of dissolved and colloidal organic matter in wastewater.

Waste and wastewater means a material, or spent or used water or waste, generated from residential, industrial, commercial, mining, or agricultural operations or from community activities that contain dissolved or suspended matter, and that is discarded, discharged, or is being accumulated, stored, or physically, chemically, thermally, or biologically treated in a publicly owned treatment works.