Section 10. Definitions

Except as defined below, the words and terms used in this chapter shall have the meanings defined in the Virginia Pollution Discharge Elimination System (VPDES) Permit Regulation (9VAC25-31).

"Annual mass load of total nitrogen" (expressed in pounds per year) means the sum of the total monthly loads for all of the months in one calendar year. See Part I E 4 of the general permit in 9VAC25-820-70 for calculating total monthly load.

"Annual mass load of total phosphorus" (expressed in pounds per year) means the sum of the total monthly loads for all of the months in one calendar year. See Part I E 4 of the general permit in 9VAC25-820-70 for calculating total monthly load.

"Association" means the Virginia Nutrient Credit Exchange Association authorized by § 62.1-44.19:17 of the Code of Virginia.

"Attenuation" means the rate at which nutrients are reduced through natural processes during transport in water.

"Board" means the Virginia State Water Control Board or State Water Control Board.

"Delivered total nitrogen load" means the discharged mass load of total nitrogen from a point source that is adjusted by the delivery factor for that point source.

"Delivered total phosphorus load" means the discharged mass load of total phosphorus from a point source that is adjusted by the delivery factor for that point source.

"Delivery factor" means an estimate of the number of pounds of total nitrogen or total phosphorus delivered to tidal waters for every pound discharged from a permitted facility, as determined by the specific geographic location of the permitted facility, to account for attenuation that occurs during riverine transport between the permitted facility and tidal waters. Delivery factors shall be calculated using the Chesapeake Bay Program watershed model. For the purpose of this regulation, delivery factors with a value greater than 1.00 in the Chesapeake Bay Program watershed model shall be considered to be equal to 1.00.

"Department" means the Department of Environmental Quality.

"Eastern Shore trading ratio" means the number of point source credits from another tributary that can be acquired and applied by a facility in the Eastern Coastal Basin. Trading ratios are expressed in the form "credits supplied: credits received."

"Equivalent load" means:

2,300 pounds per year of total nitrogen or 300 pounds per year of total phosphorus discharged by an industrial facility are considered equivalent to the load discharged from sewage treatment works with a design capacity of 0.04 million gallons per day,

5,700 pounds per year of total nitrogen or 760 pounds per year of total phosphorus discharged by an industrial facility are considered equivalent to the load discharged from sewage treatment works with a design capacity of 0.1 million gallons per day, and

28,500 pounds per year of total nitrogen or 3,800 pounds per year of total phosphorus discharged by an industrial facility are considered equivalent to the load discharged from sewage treatment works with a design capacity of 0.5 million gallons per day.

"Existing facility" means a facility holding a current individual VPDES permit that has either commenced discharge from, or has received a Certificate to Construct (for sewage treatment works, or equivalent DEQ approval for discharges from industrial facilities) the treatment works used to derive its waste load allocation on or before July 1, 2005, or has a waste load allocation listed in 9VAC25-720-50 C, 9VAC25-720-60 C, 9VAC25-720-70 C, 9VAC25-720-110 C, and 9VAC25-720-120 C of the Water Quality Management Planning Regulation. Existing facility shall also mean and include any facility, without an individual VPDES permit, which holds a separate waste load allocation in 9VAC25-720-120 C of the Water Quality Management Planning Regulation.

"Expansion" or "expands" means (i) initiating construction at an existing treatment works after July 1, 2005, to increase design flow capacity, except that the term does not apply in those cases where a Certificate to Construct (for sewage treatment works, or equivalent DEQ approval for discharges from industrial facilities) was issued on or before July 1, 2005, or (ii) industrial production process changes or the use of new treatment products at industrial facilities that increase the annual mass load of total nitrogen or total phosphorus above the waste load allocation.

"Facility" means a point source discharging or proposing to discharge total nitrogen or total phosphorus to the Chesapeake Bay or its tributaries. This term does not include confined animal feeding operations, discharges of storm water, return flows from irrigated agriculture, or vessels.

"General permit" means this general permit authorized by § 62.1-44.19:14 of the Code of Virginia.

"Industrial facility" means any facility (as defined above) other than sewage treatment works.

"Local water quality-based limitations" means limitations intended to protect local water quality including applicable total maximum daily load (TMDL) allocations, applicable Virginia Pollution Discharge Elimination System (VPDES) permit limits, applicable limitations set forth in water quality standards established under § 62.1-44.15 (3a) of the Code of Virginia, or other limitations as established by the State Water Control Board.

"New discharge" means any discharge from a facility that did not commence the discharge of pollutants prior to July 1, 2005, except that the term does not apply in those cases where a Certificate to Construct (for sewage treatment works, or equivalent DEQ approval for discharges from industrial facilities) was issued to the facility on or before July 1, 2005.

"Nonsignificant discharger" means (i) a sewage treatment works discharging to the Chesapeake Bay watershed downstream of the fall line with a design capacity of less than 0.1 million gallons per day, or less than an equivalent load discharged from industrial facilities, or (ii) a sewage treatment works discharging to the Chesapeake Bay watershed upstream of the fall line with a design capacity of less than 0.5 million gallons per day, or less than an equivalent load discharged from industrial facilities.

"Offset" means to acquire an annual waste load allocation of total nitrogen or total phosphorus by a new or expanding facility to ensure that there is no net increase of nutrients into the affected tributary of the Chesapeake Bay.

"Permitted design capacity" or "permitted capacity" means the allowable load (pounds per year) assigned to an existing facility that is a nonsignificant discharger, that does not have a waste load allocation listed in 9VAC25-720-50 C, 9VAC25-720-60 C, 9VAC25-720-70 C, 9VAC25-720-110 C, and 9VAC25-720-120 C of the Water Quality Management Planning Regulation. The permitted design capacity is calculated based on the design flow and installed nutrient removal technology (for sewage treatment works, or equivalent discharge from industrial facilities) at a facility that has either commenced discharge, or has received a Certificate to Construct (for sewage treatment works, or equivalent DEQ approval for discharges from industrial facilities) prior to July 1, 2005. This mass load is used for (i) determining whether the expanding facility must offset additional mass loading of nitrogen and phosphorus and (ii) determining whether the facility must acquire credits at the end of a calendar year. For the purpose of this regulation, facilities that have installed secondary wastewater treatment (intended to achieve BOD and TSS monthly average concentrations equal to or less than 30 milligrams per liter) are assumed to achieve an annual average total nitrogen effluent concentration of 18.7 milligrams per liter and an annual average total phosphorus effluent concentration of 2.5 milligrams per liter. Permitted design capacities for facilities that, before July 1, 2005, were required to comply with more stringent nutrient limits shall be calculated using the more stringent values.

"Permitted facility" means a facility authorized by this general permit to discharge total nitrogen or total phosphorus. For the sole purpose of generating point source nitrogen credits or point source phosphorus credits, "permitted facility" shall also mean the Blue Plains wastewater treatment facility operated by the District of Columbia Water and Sewer Authority.

"Permittee" means a person authorized by this general permit to discharge total nitrogen or total phosphorus.

"Point source nitrogen credit" means the difference between (i) the waste load allocation for a permitted facility specified as an annual mass load of total nitrogen and (ii) the monitored annual mass load of total nitrogen discharged by that facility, where clause (ii) is less than clause (i), and where the difference is adjusted by the applicable delivery factor and expressed as pounds per year of delivered total nitrogen load.

"Point source phosphorus credit" means the difference between (i) the waste load allocation for a permitted facility specified as an annual mass load of total phosphorus and (ii) the monitored annual mass load of total phosphorus discharged by that facility, where clause (ii) is less than clause (i), and where the difference is adjusted by the applicable delivery factor and expressed as pounds per year of delivered total phosphorus load.

"Quantification level (QL)" means the minimum levels, concentrations, or quantities of a target variable (e.g., target analyte) that can be reported with a specified degree of confidence in accordance with 1VAC30-45, Certification for Noncommercial Environmental Laboratories, or 1VAC30-46, Accreditation for Commercial Environmental Laboratories.

"Registration list" means a list maintained by the department indicating all facilities that have registered for coverage under this general permit, by tributary, including their waste load allocations, permitted design capacities and delivery factors as appropriate.

"Significant discharger" means (i) a sewage treatment works discharging to the Chesapeake Bay watershed upstream of the fall line with a design capacity of 0.5 million gallons per day or greater, or an equivalent load discharged from industrial facilities; (ii) a sewage treatment works discharging to the Chesapeake Bay watershed downstream of the fall line with a design capacity of 0.1 million gallons per day or greater, or an equivalent load discharged from industrial facilities; (iii) a planned or newly expanding sewage treatment works discharging to the Chesapeake Bay watershed upstream of the fall line that is expected to be in operation by December 31, 2010, with a permitted design of 0.5 million gallons per day or greater, or an equivalent load to be discharged from industrial facilities; or (iv) a planned or newly expanding sewage treatment works discharging to the Chesapeake Bay watershed downstream of the fall line that is expected to be in operation by December 31, 2010, with a design capacity of 0.1 million gallons per day or greater, or an equivalent load to be discharged from industrial facilities.

"State-of-the-art nutrient removal technology" means (i) technology that will achieve an annual average total nitrogen effluent concentration of three milligrams per liter and an annual average total phosphorus effluent concentration of 0.3 milligrams per liter or (ii) equivalent load reductions in total nitrogen and total phosphorus through recycle or reuse of wastewater as determined by the department.

"Tributaries" means those river basins for which separate tributary strategies were prepared pursuant to § 2.2-218 of the Code of Virginia and includes the Potomac, Rappahannock, York, and James River Basins, and the Eastern Coastal Basin, which encompasses the creeks and rivers of the Eastern Shore of Virginia that are west of Route 13 and drain into the Chesapeake Bay.

"Waste load allocation" means the most limiting of (i) the water quality-based annual mass load of total nitrogen or annual mass load of total phosphorus allocated to individual facilities pursuant to 9VAC25-720-50 C, 9VAC25-720-60 C, 9VAC25-720-70 C, 9VAC25-720-110 C, and 9VAC25-720-120 C of the Water Quality Management Planning Regulation or its successor, or permitted capacity in the case of nonsignificant dischargers; (ii) the water quality-based annual mass load of total nitrogen or annual mass load of total phosphorus acquired pursuant to § 62.1-44.19:15 of the Code of Virginia for new or expanded facilities; or (iii) applicable total nitrogen or total phosphorus waste load allocations under the Chesapeake Bay total maximum daily loads (TMDLs) to restore or protect the water quality and beneficial uses of the Chesapeake Bay or its tidal tributaries.

Historical Notes

Derived from Volume 23, Issue 02, eff. November 1, 2006; amended, Virginia Register Volume 24, Issue 21, eff. August 7, 2008; Volume 28, Issue 04, eff. January 1, 2012; Volume 29, Issue 04, eff. November 21, 2012.

Statutory Authority

§ 62.1-44.15 of the Code of Virginia.