[Code of Federal Regulations]
[Title 40, Volume 21]
[Revised as of July 1, 2007]
From the U.S. Government Printing Office via GPO Access
[CITE: 40CFR133.102]

[Page 546-547]
 
                   TITLE 40--PROTECTION OF ENVIRONMENT
 
         CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)
 
PART 133_SECONDARY TREATMENT REGULATION--Table of Contents
 
Sec.  133.102  Secondary treatment.

    The following paragraphs describe the minimum level of effluent 
quality attainable by secondary treatment in terms of the parameters--
BOD5, SS and pH. All requirements for each parameter shall be 
achieved except as provided for in Sec. Sec.  133.103 and 133.105.
    (a) BOD5.
    (1) The 30-day average shall not exceed 30 mg/l.
    (2) The 7-day average shall not exceed 45 mg/l.
    (3) The 30-day average percent removal shall not be less than 85 
percent.
    (4) At the option of the NPDES permitting authority, in lieu of the 
parameter BOD5 and the levels of the effluent quality 
specified in paragraphs (a)(1), (a)(2) and (a)(3), the parameter 
CBOD5 may be substituted with the following levels of the 
CBOD5 effluent quality provided:
    (i) The 30-day average shall not exceed 25 mg/l.
    (ii) The 7-day average shall not exceed 40 mg/l.
    (iii) The 30-day average percent removal shall not be less than 85 
percent.
    (b) SS. (1) The 30-day average shall not exceed 30 mg/l.
    (2) The 7-day average shall not exceed 45 mg/l.
    (3) The 30-day average percent removal shall not be less than 85 
percent.
    (c) pH. The effluent values for pH shall be maintained within the 
limits

[[Page 547]]

of 6.0 to 9.0 unless the publicly owned treatment works demonstrates 
that: (1) Inorganic chemicals are not added to the waste stream as part 
of the treatment process; and (2) contributions from industrial sources 
do not cause the pH of the effluent to be less than 6.0 or greater than 
9.0.

[49 FR 37006, Sept. 20, 1984; 49 FR 40405, Oct. 16, 1984]