Wisconsin Administrative Code
Department of Natural Resources
NR 200-299 - Environmental Protection - Wisconsin Pollutant Discharge Elimination System
Chapter NR 276 - Phosphate Manufacturing
Section NR 276.07 - Discharges from impoundments
Current through November 25, 2024
(1) A process wastewater impoundment which is designed, constructed and operated so as to contain the precipitation from the 10 year, 24 hour rainfall event for the area in which such impoundment is located may discharge that volume of process wastewater which is equivalent to the volume of precipitation that falls within the impoundment in excess of that attributable to such rainfall event when it occurs.
(2) A process wastewater impoundment which is designed, constructed and operated so as to contain the precipitation from the 25 year, 24 hour rainfall event for the area in which such impoundment is located may discharge that volume of process wastewater which is equivalent to the volume of precipitation that falls within the impoundment in excess of that attributable to such rainfall event when it occurs.
(3) During any calendar month, there may be discharged from a process wastewater impoundment a volume of process wastewater equal to the difference between the precipitation for that month which falls within the impoundment and the evaporation from the pond water surface area for that month. Such discharges shall have a pH within the range of 6.0-9.0, daily average concentrations not to exceed 35, 10, and 25 mg/1 respectively of total phosphorus, fluoride, and suspended solids, and daily maximum concentrations not to exceed 70, 30, and 50 mg/1 respectively.
(4) The 10 year and 25 year, 24 hour rainfall events for the impoundment location shall be as set forth in s. NR 205.05.
