The words and terms used in this chapter shall have the meanings defined in the State Water Control Law and 9VAC25-31 (VPDES Permit Regulation) unless the context clearly indicates otherwise, except that for the purposes of this chapter:

"Board" means the State Water Control Board. When used outside the context of the promulgation of regulations, including regulations to establish general permits, "board" means the Department of Environmental Quality.

"Central wastewater treatment facilities" means any facility that treats (for disposal, recycling, or recovery of materials) or recycles hazardous or nonhazardous waste, hazardous or nonhazardous industrial wastewater, or used material from off-site. This includes both a facility that treats waste received from off-site exclusively, and a facility that treats waste generated on-site as well as waste received from off-site.

"Chlorinated hydrocarbon solvents" means solvents containing carbon, hydrogen, and chlorine atoms and the constituents resulting from the degradation of chlorinated hydrocarbon solvents.

"Department" or "DEQ" means the Virginia Department of Environmental Quality.

"Director" means the Director of the Virginia Department of Environmental Quality, or an authorized representative.

"Petroleum products" means petroleum-based substances comprised of a complex blend of hydrocarbons derived from crude oil such as motor fuels, jet fuels, distillate fuel oils, residual fuel oils, lubricants, petroleum solvents and used oils. "Petroleum products" does not include hazardous waste as defined by the Virginia Hazardous Waste Management Regulations (9VAC20-60).

"Total maximum daily load" or "TMDL" means a calculation of the maximum amount of a pollutant that a waterbody can receive and still meet water quality standards and an allocation of that amount to the pollutant's sources. A TMDL includes wasteload allocations (WLAs) for point source discharges, and load allocations (LAs) for nonpoint sources or natural background or both, and must include a margin of safety (MOS) and account for seasonal variations.

The director, or an authorized representative, may perform any act of the board provided under this chapter, except as limited by § 62.1-44.14 of the Code of Virginia.