Section 101.12. WPDES information reporting.

  The department shall calculate effluent quantities for those pollutants whose discharge is regulated by the WPDES permit:

(1)  The department shall use the reports submitted under the reporting requirements of the permit for each calendar year.

(2)  For the purposes of this section, an analytic result reported as less than the limit of quantitation shall be applied as a zero result.

(3)  The daily flow to be used in calculating effluent quantities shall be one of the following:

(a) The monthly average flow, for persons required to monitor daily flows and report monthly average flows.

(b) The daily flow, for persons required to monitor weekly, monthly or quarterly flows and report daily flows.

(4)  The daily concentrations to be used in calculating effluent quantities shall be one of the following:

(a) The monthly average concentration, for persons required to monitor daily discharge concentrations and report monthly averages.

(b) The representative concentrations, for persons required to monitor concentrations on a weekly, monthly or quarterly basis and report a single representative value.

(5)  The department shall calculate the effluent quantities as pounds per month using the values from subs. (3) and (4) and all of the following:

(a) The department shall calculate effluent quantities for pollutants with effluent limits in effect for each month.

(b) Reported quantities shall be used in place of calculated quantities.

(c) For pollutants reported as concentrations, the effluent quantity shall be calculated as: the daily flow from sub. (3) (a) or (b) , times the daily concentrations from sub. (4) (a) or (b) , times 8.34, times the number of discharge days.

(d) For pollutants reported as quantities, the effluent quantities shall be calculated as one of the following:

1. The sum of reported quantities by month, where this represents the total discharge of the pollutant, or

2. The reported monthly average quantity times the number of discharge days.

(e) The number of discharge days shall be assumed to be the number of calendar days in each month, or the actual number of discharge days in each month where adequate information is available from the reported data to determine the number of discharge days.

(6)  The department shall mail a summary report of its calculations to the reporting person by March 1 of each year. The purpose of this mailing is to provide the opportunity for the reporting person to verify the department's use of the reported data and calculation results. Persons may request adjustments to the calculation results on the summary report with supporting documentation. The summary report must be returned by April 1 and must identify the person verifying the data. The department shall notify the person of its findings, for exceptions only, by May 1.

(7)  Quantities of substances present in water influent to a facility may be deducted from effluent quantities of such substances. To apply this deduction to municipal reporting the influent water shall be the raw water source for the public drinking water system serving the municipality, a well serving the wastewater treatment facility, or a representative private well. Facilities shall make this deduction the summary provided for their review under sub. (6) . Influent quantities shall be determined using one of the following and subtracted from the effluent quantities calculated as in sub. (5) (c) except that the difference may not be a negative number:

(a) Influent quantities of BOD and total suspended solids shall be determined by samples taken over an operational day once per month, in lieu of more frequent monitoring, and averaged for the year. Influent quantities for each month shall be calculated as the average influent concentration, times the daily flow under sub. (3) , times 8.34.

(b) Influent quantities for other pollutants shall be determined by samples taken over an operational day once per quarter, in lieu of more frequent monitoring, and averaged for the year. Influent quantities for each month shall be calculated as the average influent concentration, times the daily flow under sub. (3) , times 8.34.

Cr. Register, December, 1977, No. 264 , eff. 1-1-78; emerg. am. (2), (6) and (7), cr. (4) (c) 3., eff. 2-12-92; r. and recr. Register, February, 1994, No. 458 , eff. 3-1-94.