Section NR 270.042 - Effluent limitations representing the degree of effluent reduction attainable by the application of the best practicable control technology currently available (BPT)Except as provided in ss. NR 270.0015, 270.002 and 270.003 and 40 CFR 125.30- 125.32, any existing point source subject to this subcategory shall achieve the following effluent limitations representing the degree of effluent reduction attainable after application of the best practicable control technology currently available (BPT):
(1) The concentration of pollutants discharged in mine drainage from mines, either open-pit or underground, operated for the production of mercury ores may not exceed the following limitations: Effluent characteristic | [BPT] Effluent limitations |
Maximum for any 1 day | Average of daily values for 30 consecutive days |
Milligrams per liter |
TSS | 30.0 | 20.0 |
Hg | 0.002 | 0.001 |
Ni | 0.2 | 0.1 |
pH | (1) | (1) |
1 Within the range 6.0 to 9.0
(2)(a) Except as provided in this subsection, there may not be discharge of process wastewater to navigable waters from mills beneficiating mercury ores by gravity separation methods or by froth flotation methods.(b) In the event that the annual precipitation falling on the treatment facility and the drainage area contributing surface runoff to the treatment facility exceeds the annual evaporation, a volume of water equivalent to the difference between annual precipitation falling on the treatment facility and the drainage area contributing surface runoff to the treatment facility and annual evaporation may be discharged subject to the limitations set forth in par. (a). Wis. Admin. Code Department of Natural Resources NR 270.042
Cr. Register, October, 1986, No. 370, eff. 11-1-86.