Section NR 211.12 - Combined wastestreams(1) Where effluent from a process regulated by a categorical pretreatment standard is mixed prior to treatment with wastewaters other than those generated by the regulated process, fixed alternative discharge limits may be established by the control authority or by the industrial user with the written concurrence of the control authority. These alternative limits shall apply to the mixed effluent. When deriving alternative categorical limits, the control authority or industrial user shall calculate both an alternative daily maximum value using the daily maximum values specified in the appropriate categorical pretreatment standards and an alternative monthly average value using the monthly average values specified in the appropriate categorical pretreatment standards. The industrial user shall comply with the alternative daily maximum and monthly average limits approved by the control authority until the control authority modifies the limits or approves an industrial user modification request. Modification is authorized whenever there is a material or significant change in the values used in the calculation to fix alternative limits for the regulated pollutant. An industrial user shall immediately report any such material or significant change to the control authority. New alternative categorical limits shall be calculated within 30 days.(2) ALTERNATIVE LIMIT CALCULATION. Alternative limits shall be derived according to the following formulas: (a) Alternative concentration limit: - (b) Alternative mass limit: - (c) Where: N = The total number of regulated streams
CT = The alternative concentration limit for the combined wastestream
Ci = The categorical pretreatment standard concentration limit for the pollutant in the regulated stream i.
MT = The alternative mass limit for the combined waste-stream
Mi = The categorical pretreatment standard mass limit for a pollutant in the regulated stream i, which is the categorical pretreatment standard multiplied by the appropriate measure of production
Fi = The average daily flow over at least 30 days of stream i to the extent that it is regulated for the pollutant
FT = The average daily flow over at least 30 days through the combined treatment facility, including Fi, FD, and unregulated streams
FD = The average daily flow over at least 30 days from:
1. Boiler blowdown, non-contact cooling, stormwater and demineralizer backwash streams. However, if these streams contain a significant amount of a pollutant and if the combination of these streams with an industrial user's regulated process waste-stream prior to treatment will result in a substantial reduction of that pollutant, the control authority, upon the industrial user's application, shall determine whether these streams should be classified as diluted or unregulated. In its application to the control authority, the industrial user shall provide engineering, production, sampling and analysis and other information necessary for the control authority to make its determinations;2. Sanitary wastestreams where the streams are not regulated by a categorical pretreatment standard; or3. Any process wastestreams which were or could have been entirely exempted from categorical pretreatment standards for one or more of the following reasons:a. The pollutants regulated by the categorical pretreatment standards used in the formula are not detectable in the effluent from the industrial user;b. The pollutants of concern are present only in trace amounts and are neither causing nor likely to cause toxic effects;c. The pollutants of concern are present in amounts too small to be effectively reduced by technologies known to the administrator of EPA; ord. The wastestream contains only pollutants that are compatible with the POTW.(3) ALTERNATE LIMITS BELOW DETECTION LIMIT. An alternative pretreatment limit may not be used if the alternative limit is below the analytical detection limit for any of the regulated pollutants.(4) SELF-MONITORING. Self-monitoring to insure compliance with the alternative categorical limit shall be conducted in accordance with s. NR 211.15(4).(5) CHOICE OF MONITORING LOCATION. (a) If a treated regulated process wastestream is combined with wastewaters other than those generated by the regulated process, the industrial user may monitor either the segregated process wastestream or the combined wastestream for purposes of determining compliance with the applicable pretreatment standards. If the industrial user chooses to monitor the segregated process wastestream, the industrial user shall apply the applicable categorical pretreatment standard. If the industrial user chooses to monitor the combined wastestream, the industrial user shall apply an alternative discharge limit calculated according to the combined wastestream formula in sub. (2).(b) An industrial user may change monitoring points only after receiving approval from the control authority. The control authority shall ensure that any change in an industrial user's monitoring point will not allow the industrial user to substitute dilution for adequate treatment.Wis. Admin. Code Department of Natural Resources § NR 211.12
Cr. Register, September, 1986, No. 369, eff. 10-1-86; am. (1), r. and recr. (2) and (4), cr. (5) and (6), Register, March, 1992, No. 435, eff. 4-1-92; CR 13-006: r. (6) Register January 2014 No. 697, eff. 2-1-14.