(a) Except as provided in §§ 125.30 through 125.32, and subject to the provisions of paragraph (b) 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):
| Effluent characteristic | Effluent limitations | |
|---|---|---|
| Maximum for any 1 day | Average of daily values for 30 consecutive days shall not exceed - | |
| TSS | 20 mg/l | 10 mg/l. |
| Total Fe | 2 mg/l | 1 mg/l. |
| pH | (1) | (1) |
(b) Only that volume of water resulting from precipitation that exceeds the maximum safe surge capacity of a process waste water impoundment may be discharged from that impoundment. The height difference between the maximum safe surge capacity level and the normal operating level must be greater than the inches of rain representing the 10-year, 24-hour rainfall event as established by the National Climatic Center, National Oceanic and Atmospheric Administration for the locality in which such impoundment is located.
[40 FR 48657, Oct. 16, 1975, as amended at 60 FR 33969, June 29, 1995; 60 FR 35796, July 11, 1995]