Virginia Administrative Code › Title 9 - ENVIRONMENT › Agency 25 - STATE WATER CONTROL BOARD › Chapter 860 - VIRGINIA POLLUTANT DISCHARGE ELIMINATION SYSTEM GENERAL PERMIT REGULATION FOR POTABLE WATER TREATMENT PLANTS › Section 9VAC25-860-10 - Definitions

Current through Register Vol. 40, No. 24, July 15, 2024
The words and terms used in this regulation shall have the
				  meanings defined in the State Water Control Law and 9VAC25-31, the 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.
"Department" or "DEQ" means the Virginia Department of
				  Environmental Quality.
"Conventional filtration treatment" means a series of
				  processes including coagulation, flocculation, sedimentation, and filtration
				  resulting in substantial particulate removal.
"Membrane treatment" means a pressure or vacuum driven
				  process using synthetic materials to separate constituents from water.
				  Membranes are used for dissolved solids or suspended solids removal. Membrane
				  treatment for dissolved solids removal includes reverse osmosis and
				  nanofiltration. Membrane treatment for suspended solids removal includes
				  ultrafiltration and microfiltration.
"Microfiltration" means a method of membrane treatment
				  designed to remove particles down to 0.1 µm in size. The treatment
				  removes cysts, bacteria, and most (but not all) particulates.
"Nanofiltration" or "low-pressure reverse osmosis" or
				  "membrane softening" means a method of membrane treatment designed to remove
				  multivalent ions (softening) and removes contaminants down to 1 nm (nanometer =
				  0.001 µm) in size.
"Potable water treatment plant" means an establishment
				  engaged in producing water for domestic, commercial, or industrial use as
				  designated by North American Industry Classification System (NAICS) Code 221310
				  - Water Supply and Irrigation Systems, (Executive Office of the President,
				  Office of Management and Budget, United States, 2017), Standard Industrial
				  Classified (SIC) Code 4941 - Water Supply (Office of Management and Budget
				  (OMB) SIC Manual, 1987), or others as approved by the department.
"Reverse osmosis" means a method of membrane treatment
				  designed to remove salts and low-molecular weight solutes and remove all
				  contaminants down to 0.0001 µm (microns) in size. Reverse osmosis methods
				  apply pressure in excess of osmotic pressure to force water through a
				  semi-permeable membrane from a region of high salt concentration to a region of
				  lower salt concentration.
"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.
"Ultrafiltration" means a method of membrane treatment
				  designed to remove particles down to 0.01 µm in size. The treatment
				  removes cysts, bacteria, and viruses as well as suspended
				  solids.
Statutory Authority: § 62.1-44.15 of the Code of
					 Virginia; § 402 of the Clean Water
					 Act.