N.J. Admin. Code § 7:14A-13.8 - Calculation of effluent limitations using existing effluent quality

(a) Effluent limitations based on existing effluent quality shall be calculated according to the following procedure:

1. The maximum projected effluent concentration shall be calculated in accordance with the statistical method contained in the USEPA TSD, as amended and/or supplemented, unless the permittee demonstrates that the method in the TSD is not applicable and that an alternative statistical method more accurately estimates the maximum projected effluent concentrations.

i. The following conditions apply:

(1) If at least 10 data points are available, a site specific coefficient of variation shall be determined.

(2) If fewer than 10 data points are available, the permit shall require monitoring and include a reopener clause to include existing effluent quality limitations based on 10 or more data points.

(3) The 95 percent confidence interval and the 95 percent probability basis shall be used.

ii. Effluent data generated during a documented facility upset, or other unusual event which has been identified and appropriately remedied by the permittee, may be eliminated when determining effluent limitations based on existing effluent quality;

2. The maximum daily limitation shall be set equal to the maximum projected effluent concentration; and

3. The average monthly limitation shall be calculated from the maximum daily limitation according to the procedure described in N.J.A.C. 7:14A-13.6, using the sampling frequency required in the discharge permit. If the required sampling frequency is once per month or less, an average monthly limitation may be eliminated for that pollutant or pollutant parameter.

(b) Where an interim effluent limitation is required in accordance with N.J.A.C. 7:14A-13.11 for the time period prior to the effective date of a final effluent limitation, limitations reflecting existing effluent quality shall be calculated in accordance with (a) above.

Notes

N.J. Admin. Code § 7:14A-13.8