42 U.S. Code § 6939e - Federally owned treatment works
(a) In general
For purposes of section 6903 (27) of this title, the phrase “but does not include solid or dissolved material in domestic sewage” shall apply to any solid or dissolved material introduced by a source into a federally owned treatment works if—
(1) such solid or dissolved material is subject to a pretreatment standard under section 1317 of title 33, and the source is in compliance with such standard;
(2) for a solid or dissolved material for which a pretreatment standard has not been promulgated pursuant to section 1317 of title 33, the Administrator has promulgated a schedule for establishing such a pretreatment standard which would be applicable to such solid or dissolved material not later than 7 years after October 6, 1992, such standard is promulgated on or before the date established in the schedule, and after the effective date of such standard the source is in compliance with such standard;
(3) such solid or dissolved material is not covered by paragraph (1) or (2) and is not prohibited from land disposal under subsections  (d), (e), (f), or (g) of section 6924 of this title because such material has been treated in accordance with section 6924 (m) of this title; or
(4) notwithstanding paragraphs  (1), (2), or (3), such solid or dissolved material is generated by a household or person which generates less than 100 kilograms of hazardous waste per month unless such solid or dissolved material would otherwise be an acutely hazardous waste and subject to standards, regulations, or other requirements under this chapter notwithstanding the quantity generated.
It is unlawful to introduce into a federally owned treatment works any pollutant that is a hazardous waste.
(1) Actions taken to enforce this section shall not require closure of a treatment works if the hazardous waste is removed or decontaminated and such removal or decontamination is adequate, in the discretion of the Administrator or, in the case of an authorized State, of the State, to protect human health and the environment.
(2) Nothing in this subsection shall be construed to prevent the Administrator or an authorized State from ordering the closure of a treatment works if the Administrator or State determines such closure is necessary for protection of human health and the environment.
(d) “Federally owned treatment works” defined
For purposes of this section, the term “federally owned treatment works” means a facility that is owned and operated by a department, agency, or instrumentality of the Federal Government treating wastewater, a majority of which is domestic sewage, prior to discharge in accordance with a permit issued under section 1342 of title 33.
(e) Savings clause
Nothing in this section shall be construed as affecting any agreement, permit, or administrative or judicial order, or any condition or requirement contained in such an agreement, permit, or order, that is in existence on October 6, 1992, and that requires corrective action or closure at a federally owned treatment works or solid waste management unit or facility related to such a treatment works.
 So in original. Probably should be singular.