The following terms, when used in this division, shall have the following meanings, unless the context clearly indicates otherwise. Additional definitions for terms used in this division are found in §§115.10, 101.1, and 3.2 of this title (relating to Definitions).
  (1) Affected source category--Any of the following source categories:
    (A) organic chemicals, plastics, and synthetic fibers manufacturing industry under Standard Industrial Classification (SIC) codes 2821, 2823, 2824, 2865, and 2869;
    (B) pesticides manufacturing industry under SIC code 2879;
    (C) petroleum refining industry under SIC code 2911;
    (D) pharmaceutical manufacturing industry under SIC codes 2833, 2834, and 2836;
    (E) hazardous waste treatment, storage, and disposal facilities industry under SIC codes 4952, 4953, and 4959.
  (2) Affected volatile organic compound (VOC) wastewater stream--A VOC wastewater stream from an affected source category with either a VOC concentration greater than or equal to 10,000 parts per million by weight (ppmw) or a VOC concentration greater than or equal to 1,000 ppmw and a flow rate greater than or equal to 10 liters per minute (2.64 gallons per minute), as determined in accordance with §115.148 of this title (relating to Determination of Wastewater Characteristics).
  (3) Plant--All facilities included within the same commission account number.
  (4) Point of generation--The location where a VOC wastewater stream exits a process unit.
  (5) Properly operated biotreatment unit--A suspended growth process that generates biomass and recycles biomass to maintain biomass concentrations in the treatment unit. The average concentration of suspended biomass maintained in the aeration basin of a properly operated biotreatment unit shall equal or exceed 1.0 kilogram per cubic meter (kg/m3 ), measured as total suspended solids.
  (6) Volatile organic compounds (VOC) wastewater--Water which, as part of a facility process, has come into contact with VOC and is intended for treatment, disposal, or discharge without further use in the process unit.
  (7) Water seal controls--A seal pot, p-leg trap, or other type of trap filled with water (e.g., flooded sewers that maintain water levels adequate to prevent air flow through the system) that creates a water barrier between the water level of the seal and the atmosphere. The water level of the seal must be maintained in the vertical leg of a drain in order to be considered a water seal.
  (8) Wet weather retention basin--An impoundment or tank that is used to store rainfall runoff that would exceed the capacity of the wastewater treatment system until it can be returned to the wastewater treatment system or, if the water meets the applicable discharge limits, discharged without treatment. These units may also be used to store wastewater during periods when the wastewater treatment system is shut down for maintenance or emergencies.

Source Note: The provisions of this §115.140 adopted to be effective May 27, 1994, 19 TexReg 3703; amended to be effective November 18, 1999, 24 TexReg 10095; amended to be effective May 16, 2002, 27 TexReg 4113