(c) Effluent limitations for discharges into losing stream segments.

1. (1) Discharges to losing stream segments shall be permitted only after other alternatives including land application of wastewater, discharge to nonlosing stream segment, and connection to a regional wastewater treatment facility, have been evaluated and determined to be unacceptable for environmental and/or economic reasons.

2. (2)

   1. (A) If the Division of Environmental Quality agrees to allow a discharge to a losing stream segment, the permit will be written using the limitations described below, as a minimum.
   2. (B) Discharges from wastewater treatment facilities, which receive primarily domestic waste, or from publicly owned treatment works shall undergo treatment sufficient to meet the following limitations:

(i) Carbonaceous Biochemical Oxygen Demand (CBOD₅) or Biochemical Oxygen Demand (BOD₅) equal to or less than a monthly average of ten milligrams per liter (10 mg/L) and a seven (7) day average of fifteen milligrams per liter (15 mg/L);

1. (ii) Total suspended solids equal to or less than a monthly average of fifteen milligrams per liter (15 mg/L) and a seven (7) day average of twenty-three milligrams per liter (23 mg/L);

   1. (iii) Provisions of 40 C.F.R. § 133.102(c);

      1. (iv)

(b) (b) However, at no time shall the fecal coliform content exceed a geometric mean of two hundred (200) colonies per one hundred (100) milliliters in any water defined as an extraordinary resource water or natural and scenic waterway;

1. (v) Nitrate plus nitrite nitrogen levels shall not exceed ten milligrams per liter (10 mg/L);

   1. (vi) Ammonia, NH₃-N, limitations shall be included as necessary to prevent ammonia toxicity instream and to maintain instream dissolved oxygen; and

      1. (vii) Other parameters as deemed appropriate by the division.
      2. (d) Implementation of losing stream rule.

2. (1) Existing discharges.

   1. (A) At the time of permit renewal, or when deemed necessary by the division, NPDES permittees discharging to stream segments which may be losing stream segments, as defined above, shall submit documentation as part of the renewal permit application, showing that the segment is or is not a losing stream segment.
   2. (B) If the discharge is into a losing stream segment, then the facility must be capable of meeting the effluent limitations described above, as a minimum.

3. (2) New discharges.

   1. (A) New facilities proposing to discharge to a stream which may be a losing stream segment shall submit documentation as part of the initial NPDES permit application demonstrating that the segment is or is not a losing stream segment.
   2. (B) This documentation includes, but is not limited to, stream studies or other data, showing the stream segment does or does not meet the criteria in subsection (b) of this section.
   3. (C) If the proposed discharge is into a losing stream segment, then the facility must be designed and operated to meet the effluent limitations described above, as a minimum.

4. (3)

   1. (A) For facilities in both subdivisions (d)(1) and (2) of this section, stream studies for determining classification as a losing stream segment must be conducted during the critical low flow season, when stream flow is at least one (1) cfs and representative of seasonal flow.
   2. (B) Effluent flow, when existing, can be included in the minimum one (1) cfs stream flow.
5. (4) The division shall determine the requirement for, and the content and level of detail of, stream studies, based on local topography, geological data, file data, other dischargers in area, stream flow, etc.