15A NCAC 02B .0403. DEFINITION OF TERMS

The terms used in this Section shall be as defined in G.S. 143‑213 and as follows:

(1)           The term "commission" means the Environmental Management Commission or its successor.

(2)           The term "director" means the Director of the Division of Environmental Management, Department of Natural Resources and Community Development.

(3)           The term "staff" means the division of environmental management, or its successor.

(4)           The term "BPCTCA" shall mean best practicable control technology currently available.  Effluent limitations determined as BPCTCA are immediately applicable and shall be complied with not later than July 1, 1977.

(5)           The term "BPWTT" shall mean best practicable waste treatment technology.  Effluent limitations established by this designation shall be complied with not later than July 1, 1983.

(6)           The term "BCT" shall mean best conventional pollutant control technology.  Effluent limitations designated as BCT will control the discharge of pollutants determined to be conventional in nature and these limitations shall be complied with not later than July 1, 1984.

(7)           The term "BAT" shall mean best available technology economically achievable.  Effluent limitations designated as BAT will control the discharge of pollutants determined to be nonconventional in nature and these limitations will come into effect on July 1, 1984, and shall be complied with not later than July 1, 1987.

(8)           The term "BAT/BMP'S" shall mean best available technology economically achievable/best management practices.  Effluent limitations designated as BAT/BMP's will control the discharge of pollutants determined to be toxic in nature.  Compliance with these designated effluent limitations must be maintained not later than three years after such limitations are developed, or not later than July 1, 1984, whichever is later, but in no case later than July 1, 1987.

(9)           The term "new source performance standards" shall mean the effluent limitations required of an industrial discharger determined under the guidance of 15A NCAC 2B .0407 to be a new source.

(10)         The term "waste stabilization pond" (also called "lagoons" or "oxidation ponds") shall mean a large, relatively shallow basin designed for long term detention of wastewater which may or may not have received prior treatment.  While in the basin, the wastewater is biologically treated to reduce biochemical oxygen demand and suspended solids.  Stabilization ponds are further defined as:

(a)           Photosynthetic Pond.  A pond which is designed to rely on photosynthetic oxygenation (i.e., oxygen from algae) for any portion of the oxygen needed for waste treatment; This includes oxidation ponds and facultative lagoons.  These ponds may have supplemental aeration by mechanical means.  With regard to hydraulic flow, photosynthetic ponds are either of the:

(i)            flow‑through type, in which the pond discharges relatively continuously throughout the year; or

(ii)           controlled‑discharge type, in which the pond is designed to retain the wastewater without discharge from six months to one year, followed by controlled discharge over a short time interval (typically about one to three weeks);

(b)           Aerated Pond.  A pond which is not designed to rely on any photosynthetic oxygenation to provide oxygen needed for biological waste treatment;  Air is supplied by mechanical means.  Aerated ponds are either:

(i)            complete mix, in which sufficient energy is imparted to the wastewater to prevent deposition of solids in the pond; or

(ii)           partial‑mix, in which only sufficient energy is used to dissolve and mix oxygen in the wastewater.  Solid materials settle in the partial‑mix pond and are decomposed anaerobically.  There will be algae in the partial‑mix aerated pond, but usually far fewer than in a photosynthetic pond.

This definition does not include polishing or holding ponds which are preceded by other biochemical or physical/chemical secondary treatment processes and designed to increase their efficiency.  The pond may be single‑cell or multi‑cell.

(11)         The term "best waste stabilization pond technology" shall mean a monthly average effluent suspended solids concentration of 90 mg/l and a weekly maximum average effluent suspended solids concentration of 135 mg/l for those waste stabilization ponds that are achieving the level of effluent quality established for biochemical oxygen demand in .0406(a)(2) of this Section.

(12)         The term "minimum treatment requirements" means the effluent limitations required to comply with the designations secondary treatment as defined in 15A NCAC 2B .0406, BPWTT, BPCTCA, BCT, BAT and/or BAT/BMP's as required of a specific wastewater discharge.  Minimum treatment requirements must be met even if the receiving waters affected can or are expected to be able to accept higher pollutant‑load levels and still meet applicable water quality standards.

(13)         The term "water quality limited segment" means a segment where it is known that water quality does not meet applicable water quality standards or is not expected to meet them even after the application of minimum treatment requirements.

(14)         The term "effluent limited segment" means a segment where it is known that water quality is meeting and will continue to meet applicable water quality standards or where there is adequate demonstration that water quality will meet applicable water quality standards after the application of minimum treatment requirements.

(15)         The term "settleable solids" means the volumetric measurement of solids after a specified settling time.  The determination of settleable solids shall be made in the following manner:  one liter of the wastewater is placed in a standard Imhoff cone and allowed to settle for 45 minutes. After 45 minutes settling, the liquid layer is gently stirred and allowed to settle for 15 additional minutes.  The volume of solids is immediately read in milliliter per liter (ml/l).

(16)         The term "oxygen consuming wastes" means those wastewater discharge components recognized as being oxygen demanding in the aquatic environment.  These are generally limited by BOD(5) and NH(3)‑N.

 

History Note:        Authority G.S. 143‑215; 143‑215.1; 143‑215.3(a)(1);

Eff. February 1, 1976;

Amended Eff. August 12, 1979; November 1, 1978; December 1, 1976.