La. Admin. Code tit. 33 § IX-5905

Current through Register Vol. 50, No. 6, June 20, 2024

Section IX-5905 - Secondary Treatment

The following paragraphs describe the minimum level of effluent quality attainable by secondary treatment in terms of the parameters BOD₅, TSS, and pH. All requirements for each parameter shall be achieved except as provided in LAC 33:IX.5907 and 5911.

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 LPDES permitting authority, in lieu of the parameter BOD₅ and the levels of the effluent quality specified in LAC 33:IX.5905.A.1-3, the parameter CBOD₅ may be substituted with the following levels of the CBOD₅ effluent quality provided:

a. the 30-day average shall not exceed 25 mg/L;

b. the 7-day average shall not exceed 40 mg/L;

c. the 30-day average percent removal shall not be less than 85 percent.

B. TSS

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 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.

La. Admin. Code tit. 33, § IX-5905

Promulgated by the Department of Environmental Quality, Office of Water Resources, LR 21:945 (September 1995), repromulgated by the Office of Environmental Assessment, Environmental Planning Division, LR 30:232 (February 2004).

AUTHORITY NOTE: Promulgated in accordance with R.S. 30:2001 et seq., and in particular Section 2074(B)(3) and (B)(4)