Section 436.42 - Effluent limitations guidelines representing the degree of effluent reduction attainable by the application of the best practicable control technology currently available(a) Except as provided in §§ 125.30 through 125.32 , and subject to the provisions of paragraphs (b) and (c) of this section, any existing point source subject to this subpart shall achieve the following effluent limitations representing the degree of effluent reduction attainable by the application of the best practicable control technology currently available (BPT): (1) With the exception of operation using HF flotation, discharges of process waste water pollutants from facilities that recycle waste water, for use in the processing shall not exceed the following limitations: | Effluent characteristic | Effluent limitations |
| Maximum for any 1 day | Average of daily values for 30 consecutive days shall not exceed- |
| TSS | 45 mg/l | 25 mg/l. |
| pH | (1) | (1) |
1 Within the range 6.0 to 9.0.
(2) Except as provided in paragraphs (a) (1) and (3) of this section, there shall be no discharge of process generated waste water pollutants into navigable waters.(3) Process generated waste water from facilities employing HF flotation shall not exceed the following limitations: [Metric units, kg/kkg of total product; English units, lb/1,000 lb of total product]
| Effluent characteristic | Effluent limitations |
| Maximum for any 1 day | Average of daily values for 30 consecutive days shall not exceed- |
| TSS | 0.046 | 0.023 |
| Total fluoride | .006 | .003 |
| pH | (1) | (1) |
1 Within the range 6.0 to 9.0.
(4) Mine dewatering discharges shall not exceed the following limitations: | Effluent characteristic | Effluent limitations |
| Maximum for any 1 day | Average of daily values for 30 consecutive days shall not exceed- |
| TSS | 45 mg/l | 25 mg/l. |
| pH | (1) | (1) |
1 Within the range 6.0 to 9.0.
(b) Any overflow from facilities governed by this subpart shall not be subject to the limitations of paragraph (a) of this section if the facilities are designed, constructed and maintained to contain or treat the volume of waste water which would result from a 10-year 24-hour precipitation event.(c) In the case of a discharge into receiving waters for which the pH, if unaltered by man's activities, is or would be less than 6.0 and water quality criteria in water quality standards approved under the Act authorize such lower pH, the pH limitation for such discharge may be adjusted downward to the pH water quality criterion for the receiving waters. In no case shall a pH limitation outside the range 5.0 to 9.0 be permitted.42 FR 35851, July 12, 1977, as amended at 60 FR 33967, June 29, 1995; 60 FR 35796, July 11, 1995