[Code of Federal Regulations]
[Title 40, Volume 26]
[Revised as of July 1, 2003]
From the U.S. Government Printing Office via GPO Access
[CITE: 40CFR421.63]

[Page 483]
 
                TITLE 40-PROTECTION OF ENVIRONMENT
 
      CHAPTER I-ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)
 
PART 421-NONFERROUS METALS MANUFACTURING POINT SOURCE CATEGORY--Table of Contents
 
              Subpart F-Secondary Copper Subcategory
 
Sec. 421.63  Effluent limitations guidelines representing the degree of effluent reduction attainable by the application of the best available technology 
          economically achievable.

    Except as provided in 40 CFR 125.30 through 125.32, 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 available technology 
economically achievable:
    (a) Subject to the provisions of paragraph (b) of this section, 
there shall be no discharge of process wastewater pollutants into 
navigable waters.
    (b) a process wastewater impoundment which is designed, constructed, 
and operated so as to contain the precipitation from the 25-year, 24-
hour rainfall event as established by the National Climatic Center, 
National Oceanic and Atmospheric Administration, 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 the 25-year, 
24-hour rainfall event, when such event occurs.